---------------------------------------------------------- Kolb-List Digest Archive --- Total Messages Posted Fri 07/22/05: 41 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:56 AM - Re: M-IIIC Drivers in Iowa (PATRICK LADD) 2. 04:13 AM - Re: M-IIIC Drivers in Iowa (Chuck Stonex) 3. 04:14 AM - Re: Fw: Quiet Landings (PATRICK LADD) 4. 04:59 AM - Re: Old thread- Trips (N27SB@aol.com) 5. 05:22 AM - tom (Jimmy) 6. 05:33 AM - Re: tom o's recommended tbo for 447 (John Hauck) 7. 06:55 AM - Re: Fw: Quiet Landings (JIM HEFNER) 8. 07:24 AM - Re: Quiet Landings/Practice Dead Stick (Steve Kroll) 9. 07:34 AM - Re: tom o's recommended tbo for 447 (Jeremy Casey) 10. 07:41 AM - Re: Quiet Landings/Practice Dead Stick (robert bean) 11. 08:02 AM - Re: Quiet Landings/Practice Dead Stick (John Hauck) 12. 08:29 AM - Re: Quiet Landings/Practice Dead Stick (Rusty) 13. 08:29 AM - Re: Quiet Landings/Practice Dead Stick (N27SB@aol.com) 14. 08:49 AM - Re: Quiet Landings/Practice Dead Stick (JIM HEFNER) 15. 09:13 AM - Re: Quiet Landings/Practice Dead Stick (Ed Chmielewski) 16. 09:14 AM - Re: Quiet Landings/Practice Dead Stick (Steve Garvelink) 17. 09:28 AM - Re: Quiet Landings/Practice Dead Stick (John Hauck) 18. 09:38 AM - Re: Quiet Landings/Practice Dead Stick (John Hauck) 19. 09:51 AM - Re: Quiet Landings/Practice Dead Stick (Rusty) 20. 10:11 AM - Re: Quiet Landings/Practice Dead Stick (John Hauck) 21. 10:46 AM - Re: Re: Two Stroke Oil - personal ruin (Denny Rowe) 22. 10:52 AM - Re: tom (Denny Rowe) 23. 10:54 AM - Re: Quiet Landings/Practice Dead Stick (Chuck Stonex) 24. 11:07 AM - Re: Quiet Landings/Practice Dead Stick (Richard & Martha Neilsen) 25. 11:18 AM - 912S Rpm question (Denny Rowe) 26. 11:27 AM - Re: Quiet Landings/Practice Dead Stick (Christopher Armstrong) 27. 11:43 AM - Re: 912S Rpm question (John Hauck) 28. 12:04 PM - Re: Quiet Landings/Practice Dead Stick (Rusty) 29. 01:11 PM - Re: Quiet Landings/Practice Dead Stick (Steve Garvelink) 30. 01:21 PM - Re: Quiet Landings/Practice Dead Stick (Richard Pike) 31. 01:38 PM - Re: Quiet Landings/Practice Dead Stick (John Hauck) 32. 02:11 PM - Re: Old thread- Trips (DCulver701@AOL.com) 33. 02:29 PM - Quiet landings (flykolb) 34. 04:58 PM - Re: M-IIIC Drivers in Iowa (woody) 35. 06:30 PM - Re: M-IIIC Drivers in Iowa (Billie Futrell) 36. 06:31 PM - Re: M-IIIC Drivers in Iowa (Chuck Stonex) 37. 08:52 PM - Re: Torsional Resonance & Drive Trains (Richard Swiderski) 38. 09:01 PM - Long Sitting Rotax 582 (Kolbdriver) 39. 09:10 PM - Re: M-IIIC Drivers in Iowa (Chuck Stonex) 40. 09:10 PM - Re: VW reduction drive (Richard Swiderski) 41. 09:20 PM - Re: Long Sitting Rotax 582 (Larry Bourne) ________________________________ Message 1 _____________________________________ Time: 03:56:40 AM PST US From: "PATRICK LADD" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa --> Kolb-List message posted by: "PATRICK LADD" He didn't panic just remembered what I had told him>> Chuck, What did you tell him?. I am about to change from Challenger to Kolb and have not flown a tail dragger since I sold the Thruster many years ago. NB. The Challenger is not half as bad as this lot make out :-) Pat -- ________________________________ Message 2 _____________________________________ Time: 04:13:51 AM PST US From: "Chuck Stonex" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa --> Kolb-List message posted by: "Chuck Stonex" Pat I think you might of direct this to the wrong guy but your right about one thing, Challenger is a good plane. Golden Circle Air (T Bird) was 20 miles away until they sold it last week and it moved to Liberty Iowa and everyone flys T Bird here. It was a great plane for training but I do not want one in my hanger. I'm just hoping I can find someone to help me get some time in this M-III I am hoping to buy next week. Chuck S --> Kolb-List message posted by: "PATRICK LADD" He didn't panic just remembered what I had told him>> Chuck, What did you tell him?. I am about to change from Challenger to Kolb and have not flown a tail dragger since I sold the Thruster many years ago. NB. The Challenger is not half as bad as this lot make out :-) Pat -- ________________________________ Message 3 _____________________________________ Time: 04:14:48 AM PST US From: "PATRICK LADD" Subject: Re: Kolb-List: Fw: Quiet Landings --> Kolb-List message posted by: "PATRICK LADD" Don't come up short!! >> Hope I am not teaching granny to suck eggs here but if you line up your expected landing point with something on your plane, top of instrument panel, end of nose cone, whatever, and the expected landing point climbs above your mark, YOU WILL UNDERSHOOT . Do not try to keep the points in line as you will slowly raise your nose, lose speed and stall. Trying to stretch your glide can kill you. Conversely, if the landing point slides DOWN you will overshoot and should drop on more flap, sideslip, fishtail or whatever to lose height. Congratulations. I have never had the nerve to turn off the engine in flight unless something had already gone wrong. Cheers Pat -- ________________________________ Message 4 _____________________________________ Time: 04:59:25 AM PST US From: N27SB@aol.com Subject: Re: Kolb-List: Old thread- Trips --> Kolb-List message posted by: N27SB@aol.com In a message dated 7/20/2005 11:43:45 AM Eastern Standard Time, DCulver701@aol.com writes: > Our place is in Lake County, on lake Yale in Grand Island, Fl. Yes i > would love to see your plane with the whole trailering process. I'll be > sure to > give you a shout on the list when we get back down to Fl. Probably be in > Nov. > Dave, I finally got my DeLorme Atlas out and found Lake Yale. It is the northern most large lake on the Mount Dora Chain of lakes. It is less than 5 miles from my Dad's house. I just explored Lake Dora and Eustis last Week. I noticed that Lake Yale has a boat ramp on the SE shore. That is really good in Fla for summer flying because it gives you a headwind taxi to the ramp. If the ramp is wide enough you will have a perfect, free "Airport". I think I will go check it out in the morning and do some flying. Steve Boetto FF #007/floats do not archive ________________________________ Message 5 _____________________________________ Time: 05:22:30 AM PST US From: "Jimmy" Subject: Kolb-List: tom --> Kolb-List message posted by: "Jimmy" Either Wednesday or Thursday there was a post about engine overall and maintenance seemly from Tom, listing the TBO of a 447 to be 600 hours and a 503 at a lower time. Was this a past quote someone put on the site??????? Jimmy Hankinson 912-863-7384 Firefly 035 JYL (Sylvania) Pegasus Field (Home) 2000 Feet X 100 Feet- Grass Rocky Ford, Georgia Do Not Archive ________________________________ Message 6 _____________________________________ Time: 05:33:03 AM PST US From: "John Hauck" Subject: Re: Kolb-List: tom o's recommended tbo for 447 --> Kolb-List message posted by: "John Hauck" and | maintenance seemly from Tom, listing the TBO of a 447 to be 600 hours and a | 503 at a lower time. | | Was this a past quote someone put on the site??????? | | Jimmy Hankinson Morning Jimmy H/All: Yes. Possum pulled it out of his or Kolb's archives. I understand these TBO times are numbers Tom Olenik would recommend based on his experience repairing them, if he were the Rotax engineers in charge. Tom's numbers are similar to mine, reference the 912 series. Rotax recommends 1,500 hour TBO. I believe my 912ULS will see much more time than that before it is torn down. Don Huff has well over 2,000 hours on his 912UL and still going strong. john h ________________________________ Message 7 _____________________________________ Time: 06:55:33 AM PST US From: "JIM HEFNER" Subject: Kolb-List: Re: Fw: Quiet Landings --> Kolb-List message posted by: "JIM HEFNER" --> Kolb-List message posted by: "PATRICK LADD" > Don't come up short!! >> Hope I am not teaching granny to suck eggs here.... Pat, not at all. Good points. I learned that early on by doing spot landings at idle and as I mentioned here, my next step will be to do spot landing practice with dead stick. You really get a much better feel for the plane when you practice these things. Emergencies can be turned into non events with practice and some luck that there is a good place to aim for when it does quit. My BRS is there for that case. Hope never to try it out though. Go ahead and shut it off sometime... it's the first step to practicing something really useful and turns out to be quite a bit of fun, once you get past that first mental hurdle. Like Roger mentioned in his post, going up higher will be even more fun. Saw John H's post that someone said they would never practice this... glad you agree this is important to practice. Each to his own, but I sure want to be well practiced at this one for when the real thing happens. I'm not suggesting this for brand new fliers though. Get 100 hrs under your belt, know your plane well, practice lots of idle landings and spot landings first, then turning the engine off is not that much different. You already know how your plane handles well by then and it only performs better when you shut it off, so there are no big surprises. To me this is a key part of learning to fly safely and I was starting to feel guilty because I had put it off for so long. Hope more people will give it a try. Take care, Jim Hefner Tucson, AZ FF#022 215 hrs Do Not Archive ________________________________ Message 8 _____________________________________ Time: 07:24:25 AM PST US From: Steve Kroll Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: Steve Kroll <<<<>>>>> It was me that said that John but you misunderstood. I had already had an unannounced engine out and subsequent forced landing and it seemed to me at the time it happened that the glide was steeper with the engine off. I still don't like the idea of practicing engine outs with the ignition off. If you misjudge the distance, you can thump the airplane..... or worse, and I believe (if I survived) I would feel really stupid if I wrecked my bird while practicing dead stick with an engine that would still run. There have been many times that I have adjusted throttle during a glide to landing because I misjudged the distance. What's the old saying in flying circles...."there are old pilots and there are bold pilots but, there are no old, bold pilots". Steve Mk2 503 do not archive --------------------------------- ________________________________ Message 9 _____________________________________ Time: 07:34:27 AM PST US From: "Jeremy Casey" Subject: RE: Kolb-List: tom o's recommended tbo for 447 --> Kolb-List message posted by: "Jeremy Casey" Don Huff has well over 2,000 hours on his 912UL and still going strong. john h Last time I ask him, he was over 2300 hours...and his is certainly the hardest run 912 on the planet...full throttle, climb to 9-10K...leave the throttle right where it was and cruise 2-2.5 hours, idle power push the nose over decent (or spin it to get down quick) shut off for more gas...I always shake my head... Jeremy ________________________________ Message 10 ____________________________________ Time: 07:41:38 AM PST US From: robert bean Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: robert bean I've had a couple flameouts in my life (airplane that is) both induction icing during brutal weather. Both times no dents. -Still have never deliberately shut it down in the pattern. Guess I would want a nice BIG runway beneath. If you get a little slow 20 ft off the ground you might have a problem that the throttle would ordinarily solve. My garbage can panel has ONE switch so I won't get confused. Start/stop. BB do not archive On 22, Jul 2005, at 10:23 AM, Steve Kroll wrote: > --> Kolb-List message posted by: Steve Kroll > > <<<< that they would not take a chance practicing a dead stick > landing, > possibly breaking the airplane. >>>>>> > > It was me that said that John but you misunderstood. I had already > had an unannounced engine out and subsequent forced landing and it > seemed to me at the time it happened that the glide was steeper with > the engine off. > > I still don't like the idea of practicing engine outs with the > ignition off. If you misjudge the distance, you can thump the > airplane..... or worse, and I believe (if I survived) I would feel > really stupid if I wrecked my bird while practicing dead stick with an > engine that would still run. There have been many times that I have > adjusted throttle during a glide to landing because I misjudged the > distance. What's the old saying in flying circles...."there are old > pilots and there are bold pilots but, there are no old, bold pilots". > > Steve > Mk2 503 > > do not archive > > > --------------------------------- > > ________________________________ Message 11 ____________________________________ Time: 08:02:49 AM PST US From: "John Hauck" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "John Hauck" ignition off. If you misjudge the distance, you can thump the airplane..... or worse, and I believe (if I survived) I would feel really stupid if I wrecked my bird while practicing dead stick with an engine that would still run. There have been many times that I have adjusted throttle during a glide to landing because I misjudged the distance. What's the old saying in flying circles...."there are old pilots and there are bold pilots but, there are no old, bold pilots". | | Steve Hi Steve K/Gang: I don't agree with your philosophy, but that does not matter. Personally, I would rather take a chance of missing a 3,000 ft strip and learn how to fly my MKIII engine out than do it your way. I don't have any old sayings for you, but the example you used, above, doesn't fit pilots that do realistic training in the eventuality that the engine stops unannounced. Again, to each his own. john h MKIII ________________________________ Message 12 ____________________________________ Time: 08:29:13 AM PST US From: "Rusty" <13brv3c@bellsouth.net> Subject: RE: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Rusty" <13brv3c@bellsouth.net> Personally, I would rather take a chance of missing a 3,000 ft strip and learn how to fly my MKIII engine out than do it your way. I don't have any old sayings for you, but the example you used, above, doesn't fit pilots that do realistic training in the eventuality that the engine stops unannounced. ------------------- Hi John, If you have exactly the right circumstances to practice this, it would be fun, and you'd gain valuable experience. No doubt about it. However, miss that runway and end up in someone's yard, and you'll be hung out to dry for being reckless. Imagine having to convince an average jury that turning off the engine in your plane was a reasonable thing to do. Might as well just plead guilty. You could still make a case that this slight risk is worth taking, considering the knowledge that could be gained. I would never have considered shutting off the engine of a plane before I actually had an emergency situation. Now that I've logged a few minutes of (flaming) glider time, I'm actually more open to doing some real glide testing. Deep down, I think we don't really believe the plane will fly without power until we see it first hand, then it's not as scary as it used to be. Cheers, Rusty (starting to think SS-022 is a hurricane magnet) ________________________________ Message 13 ____________________________________ Time: 08:29:22 AM PST US From: N27SB@aol.com Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: N27SB@aol.com In a message dated 7/22/05 10:03:16 AM Central Daylight Time, jhauck@elmore.rr.com writes: > ignition off. If you misjudge the distance, you can thump the > airplane..... or worse, and I believe (if I survived) I would feel > really stupid if I wrecked my bird while practicing dead stick with an > engine that would still run. > John, I have to agree with you on this one. I am probably the lowest time pilot in a Kolb on the list but I put this whole thing in the same category as practicing Stalls. I would not practice stalls at 500 ft and I would not practice engine outs over a 500 ft long strip. Most Kolbs seem to act differently with the engine off rather than at Idle. It only makes sense to understand how yours will act. Remember that in Experimental your are the Test Pilot and have an obligation to understand all aspects of your own Unique Aircraft. Just my opinion. do not archive ________________________________ Message 14 ____________________________________ Time: 08:49:20 AM PST US From: "JIM HEFNER" Subject: Kolb-List: Re: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "JIM HEFNER" --> Kolb-List message posted by: robert bean > I've had a couple flameouts in my life (airplane that is) both induction icing during brutal weather. Both times no dents. -Still have never deliberately shut it down in the pattern. Guess I would want a nice BIG runway beneath. If you get a little slow 20 ft off the ground you might have a problem that the throttle would ordinarily solve. My garbage can panel has ONE switch so I won't get confused. Start/stop. BB do not archive ---------------------------------- Bob, if you practice landings at idle, you have already figured out how to set your glide angle, when to apply flaps, etc to land, so it is really no different with the engine off. I had practiced many many times pulling back the power to idle in the downwind leg of the pattern and gliding across base and turning final, adjusting attitude to keep the airspeed around 50, applying full flaperons and again adjusting attitude slightly as needed to flare and touch down... as I mentioned I land this way every time... not with power. If you never practice this, then dead stick landings are not advised... if you do, they are a piece of cake. I've got a 4200' paved strip to work with, so if I were nervous about making the runway I would have turned base before the end of the runway. When I touch down I can be stopped in 100' if I want with brakes, so there is little to be concerned with when you know how far the plane will glide from previous practice at idle. You mentioned your panel has one switch... that's great that you can reach your panel.... can't reach the panel in a FF, so the ignition switch is along side the seat... nice to have the redundancy to ensure you really mean to turn it off... it's like when you go to delete an email and it asked you if you're sure... I always complained when the fire alarm went off at IBM and we all had to leave the building in an orderly manner and go out to the parking lot and assemble there to make sure everyone was accounted for... wonder why they kept making us practice all those false alarms?? Like I said, each to his own and their own decisions about this. I was only sharing my experience, since I think it is something that can help us be prepared better when things don't go as planned. Cheers, Jim Hefner Tucson, AZ FF#022 215 hrs Do Not Archive ________________________________ Message 15 ____________________________________ Time: 09:13:07 AM PST US From: "Ed Chmielewski" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Ed Chmielewski" Steve/John/Kolbers all, This dead-stick thread is great, as it brings up a lot of valid points. As a former CFI I'll agree there's no 'right' or 'wrong' way for all circumstances, but for all but the unwilling I would demonstrate true dead-stick landings with plenty of altitude and to a runway of excess length. The students always remarked about the increase in glide without the windmilling prop, and the slip practice which resulted (to lose the excess altitude) was another side benefit. This is something that I feel should be practiced in advance, and not left to luck should the engine quit for whatever reason. As someone once told me, "An airplane should never surprise you, but it might disappoint you occasionally". Ed in JXN (MI) MkII/503 ----- Original Message ----- From: "Steve Kroll" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick > --> Kolb-List message posted by: Steve Kroll > > <<<< that they would not take a chance practicing a dead stick landing, > possibly breaking the airplane. >>>>>> > > It was me that said that John but you misunderstood. I had already had an > unannounced engine out and subsequent forced landing and it seemed to me > at the time it happened that the glide was steeper with the engine off. > > I still don't like the idea of practicing engine outs with the ignition > off. ________________________________ Message 16 ____________________________________ Time: 09:14:58 AM PST US From: "Steve Garvelink" Subject: RE: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Steve Garvelink" Aw come on guys I used to know a flight examiner that used to randomly shut the engine down take the keys out of the ignition and throw them out the window. I think he had a spare in his pocket but that was a random part of his flight test. Best to practice engine out over a large flat airfield or salt flats. Imho srglink -----Original Message----- From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of Rusty Subject: RE: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Rusty" <13brv3c@bellsouth.net> Personally, I would rather take a chance of missing a 3,000 ft strip and learn how to fly my MKIII engine out than do it your way. I don't have any old sayings for you, but the example you used, above, doesn't fit pilots that do realistic training in the eventuality that the engine stops unannounced. ------------------- Hi John, If you have exactly the right circumstances to practice this, it would be fun, and you'd gain valuable experience. No doubt about it. However, miss that runway and end up in someone's yard, and you'll be hung out to dry for being reckless. Imagine having to convince an average jury that turning off the engine in your plane was a reasonable thing to do. Might as well just plead guilty. You could still make a case that this slight risk is worth taking, considering the knowledge that could be gained. I would never have considered shutting off the engine of a plane before I actually had an emergency situation. Now that I've logged a few minutes of (flaming) glider time, I'm actually more open to doing some real glide testing. Deep down, I think we don't really believe the plane will fly without power until we see it first hand, then it's not as scary as it used to be. Cheers, Rusty (starting to think SS-022 is a hurricane magnet) ________________________________ Message 17 ____________________________________ Time: 09:28:50 AM PST US From: "John Hauck" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "John Hauck" would be | fun, and you'd gain valuable experience. | Rusty Rusty/Gang: You guys are making a big deal out of shooting practice dead stick landings. Next time you have an engine out I hope you "have exactly the right circumstances to practice this." If you have doubts you can not make a 3,000 ft runway from 1,000 feet AGL, engine off, you need all the help you can muster to survive as a pilot of any kind of powered aircraft. The FAA Daily Accident Briefs are full of engine outs, most of which are GA. Of course, we don't hear of all the experimental and UL engine outs. Couple weeks ago was the first dead stick I had shot in a longggggg time. I must admit, that moment of apprehension/hesitation when I reached for the kill switch. However, as soon as the 912 was shut down and things got quiet, I was relaxed and certainly enjoyed the flight and the landing. Was a good exercise which pointed out to me how rusty I was shooting dead stick landings. With 3,000 ft to land on, although way out of shape for it, I had plenty options of where on that 3,000 feet of sod I wanted to touch down. I must make it a point to get over to Wetumpka Airport more often and get and maintain proficiency shooting dead stick landings. I think proficiency is the word I have been looking for. john h MKIII ________________________________ Message 18 ____________________________________ Time: 09:38:49 AM PST US From: "John Hauck" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "John Hauck" |Best to practice engine out over a | large flat airfield or salt flats. | | Imho | | srglink srglink/All: Absolutely, cause that is where we are going to have our engine failures, every time. ;-) john h MKIII DO NOT ARCHIVE ________________________________ Message 19 ____________________________________ Time: 09:51:53 AM PST US From: "Rusty" <13brv3c@bellsouth.net> Subject: RE: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Rusty" <13brv3c@bellsouth.net> |Best to practice engine out over a | large flat airfield or salt flats. | Absolutely, cause that is where we are going to have our engine failures, every time. ;-) john h MKIII DO NOT ARCHIVE ----------------------- John, To continue this "logic", you should practice your next dead stick landings over some of those mountains in Alaska :-) Seriously, I thought my post was more for than against. I'm just pointing out the sad facts of what will happen if something goes wrong. Despite your ability to hit the runway, the circumstances still have to be right. What about the Bonanza that does a straight in approach right in your way? What about the pair of RV's that decided to line up on the runway for a formation takeoff (gotta hate those guys ). Now those aren't your fault right, so that makes it OK :-) Say I turn my engine off near the airport, and someone calls 911 (which they probably would). Do you think they will be amused? I don't see how you could possibly take exception to my statement about having the circumstances exactly right. Cheers, Rusty (practicing engine outs in my van later) ________________________________ Message 20 ____________________________________ Time: 10:11:53 AM PST US From: "John Hauck" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "John Hauck" Rust/Gang: Good idea to practice normal, expected pilot procedure, announce one's intentions prior to executing. Nothing is absolute, especially aviation. Problem with aviation is gravity. Most folks are susceptible to it. Can't stop in the middle of the exercise and try to figure out what our next action is going to be. As far as Alaska, I believe I readily admitted that should the engine have shut down, I was prepared to buy the farm, as soon as I tried every other option available, and kept flying the airplane until it stopped crashing. Don't believe there is much comparison between dead stick landing practice and the type of flying I was doing in Alaska. I wouldn't ask anyone to do that, nor am I asking anyone to practice dead stick landings. Simply sharing my own personal views of what I consider important to me to be able to better survive the exciting sport we have selected. There are not many airports, GA type, that I have experienced over the years that I could not take evasive action, should the need arise during a dead stick landing, and still make a successful landing on the taxiway, sod on the side or in between the taxiway and runway. Helps to use one's head when flying. Practice helps me learn to use my head a little better. As far as someone calling 911 because they saw me shooting practice dead stick landings at the local airport, I am not too concerned with what others might do in that case. Long as I am not doing something illegal or causing a safety hazard. Pays to think ahead of the airplane and situation. Most of the time, when we lose the engine or something else causes a forced landing, we don't have time to sit up there and think. We have to react immediately without the luxury of brain storming our way out of the situation. Immediate action. Especially in those circumstances where a parachute and altitude is a major player. john h MKIII DO NOT ARCHIVE ________________________________ Message 21 ____________________________________ Time: 10:46:48 AM PST US From: "Denny Rowe" Subject: Re: Kolb-List: Re: Two Stroke Oil - personal ruin --> Kolb-List message posted by: "Denny Rowe" Dale, That reply someone posted from Tom Olenick the other day was an old response from Tom, the poster must have kept it in his computer and reposted it to the list the other day. Denny Rowe ----- Original Message ----- From: "Dale Sellers" Subject: Re: Kolb-List: Re: Two Stroke Oil - personal ruin > --> Kolb-List message posted by: "Dale Sellers" > > he was yesterday. > ----- Original Message ----- > From: "possums" > To: > Subject: Re: Kolb-List: Re: Two Stroke Oil - personal ruin > > >> --> Kolb-List message posted by: possums >> >> At 11:10 AM 7/21/2005, you wrote: >>>--> Kolb-List message posted by: "Dale Sellers" >>> >>>Tom, >>> >>>Elaborate, if you will, on preventive as well as periodic proceedures and >>>short falls of the Cuyuna II-02. I am particularly interested in >>>weaknesses >>>and pressure testing the crankcase. >>>Any other things that I should look out for. The factory reccomendation >>>on >>>mixture is 40:to 1. I've noticed that most who run them have changed to >>>50:1. What is your feeling on this? >>> >>>Dale Sellers >>>Georgia UltraStar >> >> >> I don't know if Tom is still on the list. >> >> >> > > > ________________________________ Message 22 ____________________________________ Time: 10:52:25 AM PST US From: "Denny Rowe" Subject: Re: Kolb-List: tom --> Kolb-List message posted by: "Denny Rowe" YES! ----- Original Message ----- From: "Jimmy" Subject: Kolb-List: tom > --> Kolb-List message posted by: "Jimmy" > > Either Wednesday or Thursday there was a post about engine overall and > maintenance seemly from Tom, listing the TBO of a 447 to be 600 hours and > a > 503 at a lower time. > > Was this a past quote someone put on the site??????? > > Jimmy Hankinson > 912-863-7384 > Firefly 035 > JYL (Sylvania) > Pegasus Field (Home) > 2000 Feet X 100 Feet- Grass > Rocky Ford, Georgia > Do Not Archive > > > ________________________________ Message 23 ____________________________________ Time: 10:54:53 AM PST US From: "Chuck Stonex" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Chuck Stonex" I wonder how many pilots have died because they had a real engine out and no dead stick experiance? It does not matter if was over a salt flat or a mountain range, the emergency was the same and the results varied according to the pilots personal experiances. I'm a rookie pilot, I pray I know the correct procedures if my engine should fail. How many knew Jim Lee?? He died when the 912 on a Kolb he was flying failed because he did the wrong thing. As I understand it, he was preoccupied with restarting the engine and forgot to fly the plane. I know this because I am in the process of buying one of the planes (M-IIIC) he built and was told this by his co-builder yesterday. You cannot know too much about anything your doing. Just too little. If you asked a musician in New York how to get to Carnagy Hall, he would probably tell you "Practice, practice, practice". Chuck S --> Kolb-List message posted by: "John Hauck" |Best to practice engine out over a | large flat airfield or salt flats. | | Imho | | srglink srglink/All: Absolutely, cause that is where we are going to have our engine failures, every time. ;-) john h MKIII DO NOT ARCHIVE ________________________________ Message 24 ____________________________________ Time: 11:07:59 AM PST US From: "Richard & Martha Neilsen" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Richard & Martha Neilsen" I have one observation that I would like to share with you on this tread. When you shout down that engine you aren't locked in to a specific glide ratio. In our Kolbs we have a very powerful tool that will allow you to adjust your glide to get you to the exact landing spot you want, it is your flaps. They will not extend your glide but they WILL shorten it. As for slips they aren't real effective in our Kolbs. The first thing I did when I had a engine out was establish what I figured was my best glide speed and tried to figure were it would take me. From there I knew the maximum distance I could go and used my flaps to get me to the exact spot short of that maximum where I landed. Rick Neilsen Redrive VW Powered MKIIIc ----- Original Message ----- From: "John Hauck" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick > --> Kolb-List message posted by: "John Hauck" > ________________________________ Message 25 ____________________________________ Time: 11:18:55 AM PST US From: "Denny Rowe" Subject: Kolb-List: 912S Rpm question --> Kolb-List message posted by: "Denny Rowe" John H and other 912S users, A non lister with a 912S powered Extra and a Warp drive prop needs to know what RPM to prop his 912S to at WOT level flight. He expects to see 90mph at 5300 rpm cruise, and does not get it. Can all Mk-3 drivers (Both types) who run the 912S and Warp blades (Also both types wide and tapered tips) let me know what performance they are getting so I can forward the info to him. Denny Rowe, Mk-3 PA, still working on hanger and not flying. :-( ________________________________ Message 26 ____________________________________ Time: 11:27:10 AM PST US From: "Christopher Armstrong" Subject: RE: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Christopher Armstrong" My actual dead stick experience was zero back in 1983 when I had to shut down the engine due to my BRS chute (one of the first out there) falling out of it's Velcro closed soft pack and trailing behind the airplane, threatening to hit the pusher prop or wrap itself around the tail in as it spun in the propwash. I was able to land on the runway that I took off from and even able to stop without dragging the chute more then about 20 feet. In 2002 I had my second engine out, this time due to a fuel pump failure in an Aircoupe. This time I was just able to clear some powerlines and land in a fairly decent field and due to shear luck missed the numerous big rocks bumps and holes. Neither were fun and neither required anything of me but to fly the plane near perfectly and touchdown soft and slow. Over trees or other nasty terrain the same is going to be required, pick the best looking spot, fly the plane near perfectly, and land as soft and as slow as you can, aiming the ends of the wings at the big stuff and you at the little stuff. If you are lucky the wing will bear the brunt of it and you will survive the crash. If you are not lucky you will be really smashed, or dead. Practicing simulated or actual dead stick landings simply improves your ability to judge how far you can glide, and to manage the energy you have so that you do land at that best looking spot flying as slowly as you can. I had practiced throttle closed "dead" stick landings fairly recently before each of my real emergency landings. I am very glad I did. I am not sure that having practiced real engine out landings would have improved my results significantly. It would have given me a bit better understanding of the airplanes performance, and I would have been able to judge my landings a bit better. I certainly don't think that there should be any danger to practicing real engine out landings for a competent pilot. Pilots should only do this under good conditions, a fairly calm day, a nice big runway, and no traffic around. Learning to make all your approaches such that you don't use the throttle to bail you out in the end is probably as useful, and I feel should be standard practice for Two-stroke, auto-conversion and other "experimental" engine flyers. Long flat approaches under significant power should be reserved for people flying extremely reliable engines. Christopher Armstrong ________________________________ Message 27 ____________________________________ Time: 11:43:09 AM PST US From: "John Hauck" Subject: Re: Kolb-List: 912S Rpm question --> Kolb-List message posted by: "John Hauck" to know what RPM to prop his 912S to at WOT level flight. He expects to see 90mph at 5300 rpm cruise, and does not get it. Denny R/Gang: With any non-inflight adjustable prop: 5,500 rpm WOT (wide open throttle) straight and level flight. That works out to about 5,200 to 5,300 rpm static WOT. He may see 90 mph at 5,300 rpm as above. Barnaby Waffrain redesigned the MKIIIC and came up with a streamlined Extra. For my purposes, I can fly between 80 and 85 mph at 5,000 rpm. 5,000 rpm seems to be a comfortable cruise rpm for me and the airplane. The MKIII flies well at 80 to 85 mph cruise. john h (Prejudiced to the MKIIIc I have been building and flying since 1991.) PS: Those same numbers apply to the 912UL engine also. ________________________________ Message 28 ____________________________________ Time: 12:04:29 PM PST US From: "Rusty" <13brv3c@bellsouth.net> Subject: RE: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Rusty" <13brv3c@bellsouth.net> There are not many airports, GA type, that I have experienced over the years that I could not take evasive action, should the need arise during a dead stick landing, and still make a successful landing on the taxiway, sod on the side or in between the taxiway and runway. Helps to use one's head when flying. Practice helps me learn to use my head a little better. ------------------------- John, So rather than admit that the conditions need to be right, you will maintain that having something go wrong, and become a real emergency is good, because you get to use your head better? Your logic escapes me. Rusty (my last reply to this thread) Do not archive ________________________________ Message 29 ____________________________________ Time: 01:11:02 PM PST US From: "Steve Garvelink" Subject: RE: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "Steve Garvelink" What was meant by that is don't put yourself at un necessary risk while practicing. Doesn't mean you cant put an imaginary target on the area to see how proficient you are becoming. I used to do engine off with my eiper all the time and became quite proficient at landing on the point every time. srglink -----Original Message----- From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of John Hauck Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "John Hauck" |Best to practice engine out over a | large flat airfield or salt flats. | | Imho | | srglink srglink/All: Absolutely, cause that is where we are going to have our engine failures, every time. ;-) john h MKIII DO NOT ARCHIVE ________________________________ Message 30 ____________________________________ Time: 01:21:36 PM PST US From: Richard Pike Subject: RE: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: Richard Pike I have followed this thread with a lot of interest, and a lot of amazement. There are a half dozen grass strips within an hour of here that are at least 2,000 feet long, and several of them are surrounded by pasture fields where an off-airport landing would be nothing worse than a nuisance. No excuse not to go practice dead stick landings. Back in 1984, when all I had was a Maxair Hummer - an ultralight that had maybe half a Kolb's agility - I used to fly over a 2,000' grass strip at various altitudes and headings and turn the engine off and practice making spot landings at a predetermined place on the strip, figured it was cheap insurance. Have not practiced as many on the MKIII, but have done enough to know how it behaves. So far I have had two unplanned engine outs on the MKIII and each was nothing more than a great nuisance, with no damage. (Unless you count the green stains from the cow manure slung on the wings) Something that has not been mentioned so far is the mental and emotional spike that happens when the engine quits and you are totally unprepared psychologically for it. In my younger days, I did a bit of boxing, and the first time somebody really busts you in the nose with a good stiff jab, and Tweetie Bird starts flying around your head, your brain wants to draw a blank. You are mentally and psychologically unprepared for such a barbaric event to happen. But after you get used to it, then it's just something you deal with. Having an engine out is a bit like that. Suddenly everything gets quiet, and the brain wants to draw a blank. But if you have previously gotten used to it, then it's just something you deal with. I expect that there are many pilots on the list who are much more competent than I, but IMO, competence also consists of being able to stick your airplane into a 500' strip, dead stick, ten times out of ten, and still be able to use it afterward. Can I do that? Probably not right now, but I plan to be able to do it by this time next year. Richard Pike MKIII N420P (420ldPoops) do not archive ________________________________ Message 31 ____________________________________ Time: 01:38:49 PM PST US From: "John Hauck" Subject: Re: Kolb-List: Quiet Landings/Practice Dead Stick --> Kolb-List message posted by: "John Hauck" maintain | that having something go wrong, and become a real emergency is good, because | you get to use your head better? Your logic escapes me. | | Rusty (my last reply to this thread) Rusty/All: You're worse than a TV reporter. Your changing my stuff and trying to put words in my mouth. ;-) Reread my post. First paragraph first!!! I'm not maintaining do diddly squat. Want to do a dead stick landing, announce your intentions, make sure it is safe, then execute it. If the situation changes, try to make a good decision.................... Before you grade me on logic, try reading and understanding what I wrote correctly. john h DO NOT ARCHIVE ________________________________ Message 32 ____________________________________ Time: 02:11:58 PM PST US From: DCulver701@AOL.com Subject: Re: Kolb-List: Old thread- Trips --> Kolb-List message posted by: DCulver701@aol.com Hi Steve, read your post on locating Lake Yale on your map. Our place is on the N.W. corner of the lake, just above a big Baptist retreat, off of Hy. 452. Its called Sunlake Estates, a retirement community with approximately 250 homes. There is a marina with about 40 boat slips, with the boat ramp being a short distance away. There,s also a public dirt ramp directly adjascent to our community. Should be easy to spot. Best regards, Dave Culver ________________________________ Message 33 ____________________________________ Time: 02:29:26 PM PST US From: "flykolb" Subject: Kolb-List: Quiet landings --> Kolb-List message posted by: "flykolb" Kolbers: I have had three dead stick landings. 1 - In the pattern on downwind, unexpected engine out, landing no problem 2 - just took off from short grass strip, unexpected engine out, landing no problem. 3 - just took off from my grass strip, "kind of" expected engine out, turned back but was high. Dove for strip. Flaps would not do it so did away with flaps and just dove. Landed on the last 1/3 of runway (2000' grass strip), no problem. It is amazing how that big fan keeps the pilot cool. When it stopped it got very warm! Jim Mark III ________________________________ Message 34 ____________________________________ Time: 04:58:20 PM PST US From: "woody" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa --> Kolb-List message posted by: "woody" I told him that if something happened like getting unexpectedly airborn don't panic just fly the plane. He was a pilot but it still took him 3 passes to figure out the right approach to land. No panic to get it back down just kept flying untill he got things figured out. Perhaps I am to used to Kolbs. Flying a Challenger was the most frighteneing experience I had had in years. I was not prepared for the extra rudder needed to stop a turn. These planes need rudder or it won't get out of a turn, The extra stiff rudder pedals and lack of concern about rudders in the Kolb had me circling for 10 minutes (felt like hours) trying to figure out what to do next. Finally a hard kick to the rudders got some movement and I straightened up. Quite frightening. I tried another Challenger that day with the same result and need for rudder. Still could not keep the nose from wandering around. I do understand the aircraft exported to the UK have bigger rudders and may be less needy of rudder input. You're going to love the Kolb ----- Original Message ----- From: "PATRICK LADD" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa > --> Kolb-List message posted by: "PATRICK LADD" > > He didn't panic just remembered what I had told him>> > > Chuck, > What did you tell him?. I am about to change from Challenger to Kolb and > have not flown a tail dragger since I sold the Thruster many years ago. > NB. The Challenger is not half as bad as this lot make out :-) > > Pat > > > -- > > > -- > > ________________________________ Message 35 ____________________________________ Time: 06:30:51 PM PST US From: "Billie Futrell" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa --> Kolb-List message posted by: "Billie Futrell" I would just like to add a little to what Woody has just said about a Challenger. I was going to buy a Challenger before I bought my Kolb. A friend of mine had a Challenger with the long wing so I flew with him for 3 hrs.I won't to tell you that was all I wanted. The first hr I was chasing the thing all over the sky. You want to make a correction to the left, so you give it aileron and it goes more to the right and then to the left. The second hr I figured out that you had to fly with rudder, and a lot of that and follow up with aileron. The only problem was before the hr was up I had cramps it the calves of my legs so bad I could hardly use my the rudder peddles. The third hr was not any better and when I left the field that day I knew I did not want a Challenger. I'm glad I go a kolb. Bill Futrell MK111Xtra912 Do not archive ----- Original Message ----- From: "woody" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa > --> Kolb-List message posted by: "woody" > > I told him that if something happened like getting unexpectedly airborn > don't panic just fly the plane. He was a pilot but it still took him 3 > passes to figure out the right approach to land. No panic to get it back > down just kept flying untill he got things figured out. > Perhaps I am to used to Kolbs. Flying a Challenger was the most > frighteneing experience I had had in years. I was not prepared for the extra > rudder needed to stop a turn. These planes need rudder or it won't get out > of a turn, The extra stiff rudder pedals and lack of concern about rudders > in the Kolb had me circling for 10 minutes (felt like hours) trying to > figure out what to do next. Finally a hard kick to the rudders got some > movement and I straightened up. Quite frightening. I tried another > Challenger that day with the same result and need for rudder. Still could > not keep the nose from wandering around. I do understand the aircraft > exported to the UK have bigger rudders and may be less needy of rudder > input. > You're going to love the Kolb > > > ----- Original Message ----- > From: "PATRICK LADD" > To: > Subject: Re: Kolb-List: M-IIIC Drivers in Iowa > > > > --> Kolb-List message posted by: "PATRICK LADD" > > > > He didn't panic just remembered what I had told him>> > > > > Chuck, > > What did you tell him?. I am about to change from Challenger to Kolb and > > have not flown a tail dragger since I sold the Thruster many years ago. > > NB. The Challenger is not half as bad as this lot make out :-) > > > > Pat > > > > > > -- > > > > > > -- > > > > > > ________________________________ Message 36 ____________________________________ Time: 06:31:49 PM PST US From: "Chuck Stonex" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa --> Kolb-List message posted by: "Chuck Stonex" I am actually very excited about flying this M-III. I talked to one of the orginal builders and got a very positive history. He actually told me what the plane was like. the only thing different was that according to him it had aluminum diamond plate on the floor. Now it has smooth aluminum for some reason. There are no indications of damage so maybe someone need the diamond plate for something else. I do want to get rid of the 618 on it though. See if I can get a 582 or equivilent. Chuck --> Kolb-List message posted by: "woody" I told him that if something happened like getting unexpectedly airborn don't panic just fly the plane. He was a pilot but it still took him 3 passes to figure out the right approach to land. No panic to get it back down just kept flying untill he got things figured out. Perhaps I am to used to Kolbs. Flying a Challenger was the most frighteneing experience I had had in years. I was not prepared for the extra rudder needed to stop a turn. These planes need rudder or it won't get out of a turn, The extra stiff rudder pedals and lack of concern about rudders in the Kolb had me circling for 10 minutes (felt like hours) trying to figure out what to do next. Finally a hard kick to the rudders got some movement and I straightened up. Quite frightening. I tried another Challenger that day with the same result and need for rudder. Still could not keep the nose from wandering around. I do understand the aircraft exported to the UK have bigger rudders and may be less needy of rudder input. You're going to love the Kolb ----- Original Message ----- From: "PATRICK LADD" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa > --> Kolb-List message posted by: "PATRICK LADD" > > He didn't panic just remembered what I had told him>> > > Chuck, > What did you tell him?. I am about to change from Challenger to Kolb and > have not flown a tail dragger since I sold the Thruster many years ago. > NB. The Challenger is not half as bad as this lot make out :-) > > Pat > > > -- > > > -- > > ________________________________ Message 37 ____________________________________ Time: 08:52:41 PM PST US From: "Richard Swiderski" Subject: RE: Kolb-List: Torsional Resonance & Drive Trains --> Kolb-List message posted by: "Richard Swiderski" Kolb Gear Heads: Below is an article I found on torsional resonance which is an incredible insight into what is lurking in all our engines. It's a fascinating story. If you are building or modifying a reduction drive this will be a sobering read. All others, it will give you an appreciation of the engineering that makes our fun possible. I don't know where I originally acquired this, so I can't give due credit to the author. PS: In this article, there is an illuminating insight into spag clutches that we were wondering about a while back. Richard Swiderski SlingShot Turbo Suzuki still in the oven. PROPELLER DRIVE SYSTEMS AND TORSIONAL VIBRATION Don brings his unique experience in testing of aircraft to these pages. A graduate of Northrup University and life long interest in new aeronautical concepts, his concerns for safety and progress of auto engine conversions prompted this article. Hopefully, his information will create a better awareness of the engineering challenge facing experimenters in modern aircraft power plant development. We welcome additional articles on the subject. MCM By Donald P. Hessenaur As aircraft engine prices continue to rise beyond the reach of most who would like to build and fly their own aircraft, many are turning to alternate power sources. This is not a new phenomena. From the Wright brothers on, many have designed, built or converted engines to aircraft use. At one time or another engines have been used from automobiles, motorcycles, outboard motors and even snowmobiles, with varying degrees of success or failure. AUTO ENGINE CONVERSIONS Today many automotive engine conversions are appearing on the aviation scene. They are definitely a viable alternative. The automotive engine today is veny advanced technically and relatively low in cost when compared to Lycomings and/or Continentals. Unfortunately, automotive engines are designed and optimized for the automobile and not for aircraft. Generally auto engines operate at a much higher RPM. The torsional vibration characteristics of a given engine, connected to a transmission, drive train and wheels, are quite different from that of the same engine, connected to an aircraft propeller. The damping action of the tires on the road and the inertia effects of the mass of the automobile are not even close to the damping/inertia effects of a propeller turning in air. TORSIONAL RESONANCE In recent years, I have developed a concern that many of the individuals and/or companies involved in the development of auto conversions do not seem to have an understanding of the problem of torsional vibration. I'm notsaying that this is true in every case. Some appear to have a profound knowledge of torsional vibration but others seem to dismiss it as a minor problem. They feel all they need to do is just stick in a rubber damper, freewheel clutch or some other quick fix and maybe the problem will go away. My experience has been that torsional vibration just doesn't go away. It can be the life or death of an entire project, not only technically, but it can also lead to a financial black hole for the individuals or company involved! The potential for success in such a project would be much higher if the individuals involved knew what they were dealing with and would use valid aircraft engineering procedures during the design and development of an engine. Creativity and experimentation should be encouraged but one must also realize that 9 times out of 10, what was thought to be a new and original solution to a problem has probably been tried by a number of people in the past. The same laws of physics, dealing with torsional vibration, are still in effect today, as they were 20 to 50 years ago. I would be the first to admit. I do not have all the knowledge on vibration in rotating systems. Nevertheless, I have had some unique experiences with tonsionals and other associated vibration problems. It is my hope that by relating them, someone will be saved from some grief. FIRSTHAND EXPERIENCE in the past I have had the opportunity to have worked on three interesting projects each of which involved torsional vibration problems to one degree or another The first was the Avian 2-t80 gyroplane which was developed in Georgetown, Ontario, Canada in the early 60's. The performanoe and handling of this gyroplane has not been surpassed by any other in its class to this day. The second was the BD-5 'Micro" kit aircraft developed in Newton, Kansas by Jim Bede in the early 70's. The third was the RotorWay RW-133 helicopter engine developed by B.J Schramm in the mid-70's. AVIAN VIBRATION ENCOUNTERS The Avian gyrocopter was a pusher design with a ducted Hartzell propeller. The rotor was an articulated 3 bladed semi-rigid, high inertia design. For this reason, a substantial drive system was required for rotor spin-up. On the original prototypes there was a 3 inch wide, heavy duty,square toothed belt that transmitted engine power from a smaller driver sprocket to a large driven sprocket at the base of the rotor hub. Occasionally, during a spin-up, this belt was stretched by some horrendous load so that the belt teeth would no longer engage the teeth on the driven sprocket causing the belt to ride up on top of the sprocket teeth. The resulting high load on the sprockets caused the structure that supported the bearings to collapse (A round toothed HTD type belt would have eliminated the riding up problem of the square tooth belt but it had not as yet been developed in the early 60's.) About this time, Avian started to develop and build their last prototype. It was totally redesigned and much improved in every way over the previous prototypes. One area of improvement was the rotor spin-up system The upper belt width was increased to 4 inches and the structure that supported the sprocket bearings was made more substantial. A new hydraulic multi-plate clutch was designed with more torque capacity and mounted over the engine near the propeller end. This improved drive gave the new prototype absolutely phenomenal jump take-off performance. The gyroplane was capable of jump take-off to 50 ft. The problem of the upper bed drive had been solved by the brute strength approach, using a stiffer support structure along with a wider belt and sprockets. Nevertheless, as time went on other problems started to show up. The lower belt drive, that took power off the engine seemed to flop a lot at various times. After a few spin ups the clutch would become very hot and eventually turn blue in color. If the cowling was removed, immediately after a spin-up the clutch would appear to have been red hot. The torsional loads going through the drive system appeared to be much higher than the original analytical numbers indicated. I had heard about torsional vibration during my college years but at the time it never hit me that the problem with the drive system involved torsional vibration. As far as I know, the clutch problem was never solved. FLUTTER & VIBRATION TESTING While at Avian I was assigned to work with a consultant who was hired to do ground vibration testing and a flutter analysis on our new prototype. This was a relatively new technology and he was the only person who did this kind of work at the time. Although he was from Tononto, Canada, he worked throughout the American aerospace industry. His equipment included a number of vibration shakers that were attached to the airframe, making it vibrate at various input frequencies. The shakers were controlled from a control panel. A number of magnetic vibration sensors were attached to the airframe, along with one that was hand held, so it could be moved around. These pickups were used to sense the resulting amplitudes of vibration at various points on the airframe. This information was then displayed on an oscilloscope. He was able to adjust the input frequency, so that various parts of the airframe would vibrate at their respective resonance frequency. The needles on the instruments, the door handle, the plexiglass in the side window, a duct support struct or the rudder could all be made to vibrate at their individual resonance frequencies. It was really weird. In fact, it appeared downright mysterious to see this engineer adjust the input frequency and shake any part he wished on the airframe.. He made a frequency survey of everything that resonated on the gyroplane. This was used to determine if anything resonated within the operating frequency range of the engine, drive system or rotor, that might cause a failure in the future. With this analysis, we found a number of parts that needed to be stiffened or redesigned so they would not vibrate or flutter in flight. During the 3 days I worked with this engineer as his assistant, I received a wealth of knowledge about vibration and resonance in aircraft. BEDE AIRCRAFT I was interviewed and offered an engineering position with Bede AincraH by Burt Rulan. My employment started on July 6, 1972. After the Avian years, my interest in the entire subject of vibration expanded and I became fully aware of torsional problems in rotating systems. Many spare hours were spent hitting engineering texts and reading numerous articles on the subject, including many by Molt Taylor. I was really curious as to how they had solved the torsional vibration problem in the BD-5. During the finst week at Bede, Les Berven was flying the BD-5 every day. When it would come down aher a flight, the mechanics would open up the engine compartment to take a look to see what was going on It wasn't long before I realized there were a number of problems they were laying to deal with. The engine was having cooling and mixture problems while trying to maintain the EGTs and CHTs below redline. The problem that really caught my attention was the overheating of the belt and sheaves. At that time they were running a snowmobile belt on variable ratio sheaves. The overheating clutch at Avian came to mind when I noticed these sheaves were quite discolored from the high temperatures involved. TORSIONALS AT BEDE During the following weeks they seemed to be doing a lot of ground testing. I had been assigned the responsibility for the weight and balance control for the BD-5 program, as I had done at Avian. Like the Avian 2-180, the BD-5 had a severe aft CG problem. One day they had been running the BD-5's engine on the ground for a period of time and all of a sudden there was a big explosion. The belt had disintegrated, with pieces all over the tarmac. These pieces of belt were as hard and bridle as bakelite plastic. As soon as I saw what happened, I knew the problem was torsional resonance. I mentioned this to the other engineers and they looked at me sort of strange. They thought I was joking and did not pay too much attention to my comment, since I was just the new engineer. HTD UNIROYAL BELT Soon after the belt incident some belt people were invited to come and look at our situation The representatives brought a number of belts such as standard V, poly V and various toothed belts. One belt that I had never seen before, caught my eye. It was a unique round toothed belt, an 6mm HTD belt. Aher all the problems associated with square toothed belts at Avian, when I saw that round toothed belt, I knew this was an exceptional design. It could be used on an aircraft and give much more reliability than one with square teeth. Best of all, the power loss was exdremely low, since it ran at low friction levels, resulting in considerably less heat buildup About this bme I was asked to start investigating various belt systems and get involved in the drive system and engine installation problems. Along with this assignment, I continued to head up a weight reduction program, particulafiy in the aft part of the ship. It was my intent to not only solve the drive system and engine installation problems but to save weight in those areas as well. Anything that could be done to remove weight, aft of the CG, would permit lead to be removed from the nose. So started working on a new drive system, using the 8mmHTD belt. Once it was put together and running, it seemed at first to perform quite well, but I soon noticed there was a lot of flapping of the belt at certain RPMs. We tightened the belt as much as we could but the flapping just seemed to persist. Nevertheless, it seemed to solve the problem for the moment and Les Berven put in a lot of flight time. Eveny once in a while we would have a failure but we would replace or repair the part and keep going. During this time we actually had more of a problem with the snowmobile engine. Various magazines were coming out with articles on the BD-S. It was becoming very popular and kit sales were climbing. ENGINE MOUNT FAILURE One significant event that occurred was the failure of the engine mount due to fatigue. The mount was welded upchrome-moly tubing and had a strange crystallized break. When I saw it, I knew it had something to do with the torsional vibration that was still in the system. A new heavier piece of tubing was welded in to make it stronger and beefier but during the next few flights it proceeded to break again. At this point a new heavier engine mount was fabricated and installed but soon after another failure occurred. This time the engine mount survived but the sheet metal channels that transferred the engine load into the fuselage, along with portions of the fuselage itself,were severely cracked. Also, numerous rivets were starting to work loose in the airframe. All that we had accomplished was to transfer and chase the problem from one area to another. The torsional problem was still with us. The biggest problem I had was that no one would believe me. At least the belt was holding up and no longer a problem. MYSTERIOUS SHAFT FAILURE The drive system difficulties were totally overwhelmed by the problems with the two stroke engine. To keep the planes flying for demonstrations and air shows, we were forced to place the highest priority on keeping the engines running. (If only the Rotex 562 had been available, we might have eliminated a major problem with the BD-5!) Cooling was a real difficult problem and one evening I and many of the engineering personnel stayed almost all night to find a solution. Burt was really frustrated with this cooling problem. In a last ditch effort, he got one of the giant portable electric shop fans, hooked it up to a large duct and then attached the duct to the open BD-S engine compahment. He felt if we couldn't get the engine to cool properly with this fan, there was no way we were going to get it to cool in the air. We ran the engine at full power and cycled the engine off and on a number of times. All of a sudden during one of the runs, something broke loose and the engine immediately went up to a very high RPM and seized. We found the propeller could turn freely without turning the drive belt or the engine. We looked all around and through everywhere and couldn't see where any break had occurred. No shaft had broken, nothing had failed that we could see. It was a real mystery. BD-S HTD belt drive components Tests were run on various belt widths to establish useful life recommendations. The drive system we had at that time used the HTD belt with the original upper main shaft. If I remember correctly, the O.D. of this shaft was about 3 inches and approximately 4 feet long. I am not sure of the wall thickness but it may have been .125 inches. This shaft had a machined bearing support fitting on each end, with the propeller mounted on the rear hub fitting and the HTD sprocket mounted on the front sprocket fitting. These end fittings were mounted to the inside diameter of the shaft, with three AN-4 bolts on each end, screwed radially into the shaft. The bolts were quite short so the threads went right up to the head, placing threads right in the shearing intersection between the fittings and the shaft itself. It was these 3 bolts at each end that transferred the torque from the HTD sprocket to the propeller hub at the rear. This was the configuration of the upper shaft when I arrived at Bede. Having bolts transfer torque in shear through the threaded area is not exactly a textbook design procedure but it had held for a year or more. TORSIONALS STRIKE AGAIN So we got the mechanic and started taking everything apart. When we pulled out the upper shaft, we found that all 6 bolts, 3 on each end, had failed precisely at the same time Now this was weird or like black magic. You would think that if something was going to fail, maybe the rear end would be ready to go but the front end might break loose first, relieving the load, then the back end would not fail. But no both ends of the 4 foot shaft failed precisely at the same bme, with all 6 bolts failing the same way. They were all crystallized and appeared to have been working in there for some time. By this time, Burt and the others had become believers in torsional resonance. Immediately we got on the phone, woke Jim Bede up and clued him in on what had happened. Within a week or so Jim brought in Al Beaufrere, a vibration expert from Long Island. I was assigned to work with him to solve the torsional problem. He came up with two different test drive systems. They were quite heavy and complicated but they did give us a direction in which to go. While Al was at Bede, I tried to learn all I could from him. This knowledge: combined with what I had picked up previously, gave us the insight that eventually led to a solution to our dilemma. THE MOLT TAYLOR DYNAFLEX SYSTEM After Al left, I started to design a new drive system, using the principles learned. It was about this time that many of the engineering staff were moved into the new Bede Product Development building. I was given an office withan other engineer named Larry Heuburger, who belive helped design the Derringer twin engine airplane. Larry knew Molt Taylor quite well and was able to persuade Jim Bede to let him design and build a small dynaflex coupling out of aluminum. I must say he did a beautiful job and came up with a real neat small dynaflex, which mounted right onto the engine. They used it with the HTD belt system and large upper shaf that I had running at the time. Ot appeared to successfully dampen out the torsional vibration. At the same time they were testing the dynaflex system I was coming right along with the design and fabrication of my new drive system. I forget just how long they flew the Molt Taylor system but one day an in flight failure occurred and Les had to deadstick the plane in. With all the engine problems this was quite a common occurrence so it was no big deal. It was found that the dynaflex had broken loose from the engine. A closer examination revealed that the crankshaft had broken clean off. The break was completely crystallized and it was difficult to discern whether it was a torsional break or a lateral break. We were not able to determine why this failure occurred. It may have been due to the rocking couple of the engine. Unfortunately, this failure ended funkier work on the dynaflex system. THE BROOMSTICK SHAFT I had come to the conclusion, based on the information from Al Beaufrere, that we needed to drastically lower the torsional frequency of the drive system by lowering its torsional spring constant. Stan Welles, our stress analyst, came up with a 6061-T6 aluminum shaft, with an outside diameter of 1 inch and a .095 inch wall thickness. This shaft came to be known as our "broomstick shaft". The same tubing size was used for both the upper main shaft and the lower jackshaft. Very soft rubber, donut type flexible joints were mounted on each end of the jackshaft. This lower shaft assembly transferred the power from the engine to the lower HTD sprocket while allowing for engine motion. The sprockets were made of a rag-filled bakelite type plastic by the Budd Corporation and are no longer available. They had wear characteristics, designed to be compatible with the HTD belt and had considerably less wear than anodized aluminum sprockets. Also they were lighter in weight. The lower sprocket was mounted on an adjustable casting that was mounted on the rear bulkhead of the engine compartment. The belt went up to the upper sprocket, which was attached to the forward end of the upper shaft. The drive ratio was 1.6 to 1.0. Bearings within the sprockets took the belt loads, which were relatively low since the belt was not preloaded. There was no need to have a tight belt with a torsionally soft system. Since the upper main shaft was only 1 inch OD, two bearings were mounted along its length to tune out lateral vibrations. Another bearing was mounted off the rear hub to take out the propeller loads. (Later, after I left Bede, Dan Cooney added another bearing towards the rear, to more effectively take out gyroscopic propeller loads ) FRlCTlON JOINTS The shaft end fittings on the lower jackshaft and the propeller hub on the upper shaft were attached with press-shrink friction fits. The fitting for the upper sprocket on the forward end of the upper shaft was a removable collet type friction fit. These friction fits were more than sufficient to carry the torque of the engine and were one of the design guidelines given to me by Al Beaufrere for joints subject to torsional vibration. This was a very, very lightweight system. The weight of the entire drive system was reduced by over 40 percent and this went a long way towards solving the aft CG problem in the BD-5. For test purposes, the prototype drive systems were designed and fabricated with zero safety factors. The first version of the "broomstick' drive did not have a freewheel clutch and when we first ran the system, we found out there was still much to be learned before the torsional problem was solved. LOW FREQUENCY TORSIONALS The vibration characteristics of the new prototype system was quite different from the previous systems. One could tell something radical had changed. The resonant point had been lowered below 600 RPM, the starting RPM of the engine. With such a low frequency and high amplitude of vibration, it was possible to visually hear and see the resonance occurring. One could see torque reversals occurring at the prop. The aircraft would violently shudder and shake itself apart, if allowed to continue. As the throttle was advanced, the RPM would get hung-up at the torsional point. Les could give it full throttle and it would just soak up all the energy from the engine, preventing the RPM from going through the torsional barrier. Occasionally, more by chance than anything, the RPM would pass through the resonance and then become super, super smooth. Likewise, when the engine was shutdown, the RPM would momentarily hang-up at the resonance point. All of a sudden, the plane would shudder and shake until all the energy of momentum was used up. Then the propeller would stop rather abruptly. It was the weirdest thing. Although we were successful in moving the torsional resonance point to a lower energy level, we had not eliminated the problem. Numerous experiments and tests were tried. At times, we were able to go into resonance with the ignition and fuel off using only the electric starter. About the same amount of shudder and vibration was produced through the aircraft when excited by the engine compression alone, as it did when the engine was running under its own power in resonance. At this point, we started to realize we had something here that was really mysterious. This led to an experiment where we replaced the two spark plugs with compression release valves, hooked up to a common control handle. With the engine and system turning over using the starter alone, the vibration and shudder in the plane instantly disappeared and became as smooth as silk, as soon as we opened the compression release valves. As soon as we would close the valves, the vibration and shudder would return. We could start and stop the resonance at will. Clearly, it could be seen that the resonance could be excited by compression strokes alone. The thing that blew our minds was that even when the input energy was low, the output loads were still as destructive to the airframe as when the input energy was high INFINITE LOADS? When we started to look into torsional resonance theory we found an explanation. Without any damping in the system, theoretically the peak load at resonance reaches infinity. That's why the input load had very little effect on the output load. Now many have said that it was just theoretical and there isno situation where any material would have zero damping qualities. Well, how much was the damping effect? We do not really know at this point. If the damping were to bring the load down to one tenth of infinity, that would still be a big load. What I am getting at is this: The loads are very high during resonance and are not entirely dependent on the input load. THE FREEWHEEL CLUTCH The idea for the freewheel clutch came from our machinist, Ray Johnson, and I must give him the credit. He came in one day and told me that when he was a kid, his dad had a thrashing machine on the farm They would run the belt from the tractor to the thrashing machine and it had a freewheel device on it so that any vibration coming from the old two cylinder John Deere would be somehow taken care of. The minute he said "freewheel clutch", it rang a bell. After previously seeing the oscillating torque reversals of the prop I knew we needed some way to allow a torque reverse to occur without the bounce back. I had been looking at centrifugal clutches, manual clutches, etc. that could be used to disengage and allow some slip. We even tried a test with a super loose belt with idler pulleys but the slop still wasn't enough. The torsional amplitude was just too great at the low system frequency we were dealing with. Immediately after Ray mentioned the freewheel clutch, I started investigating and found a Borg Warner clutch that was used in automatic transmissions It was a double cage, full phasing sprag clutch. The double cage caused all the little cams inside to engage precisely at the same time. I had previously had experience with freewheel roller type clutches at Avian but we had problems with the brinelling of the clutch races when one roller would engage before the others and momentarily take the full torque, causing eventual clutch failure. The doublecage full phasing, sprag clutch solved this problem. It took a month or two to design and have the clutch parts made. The clutch itself was mounted on the front of the upper plastic sprocket. It had its own bearing to maintain the clutch concentricity. The inner clutch race was integrated with the collar that transferred the torque to the upper 1" shaft. The heat treat for the clutch races and collet was somewhat complicated and expensive but at that point we weren't looking at the cost, as much as just trying to find something that was lightweight and workable. At that time I was under tremendous pressure at Bede to try to get this system working. After a lot of hard work the parts were made, Everything went together beautifully and the clutch was mounted in the airplane. About that time, our engine company had some problems and we could not get any engines. I had the drive system in the ship shortly after New Years but it sat until sometime in March before we were able to get an engine to test it. So, I was sitting that whole time wondering if it would work. Finally the engine arrived. The mechanics installed it and started it up. It was super smooth. There was no sign of any shudder or vibration in the aircraft due to orsionals. The first tests were so successful that Les took the plane up. He came back with a big smile on his face and told us it was the smoothest drive system he had ever flown. Jim was relieved and happy, like, real happy! We had solved the torsional problem. Dyno test stand used for RotorWay engine development, air show demonstrations, and producting engine run-ins. DUAL FREQUENCY SYSTEM According to theory when the stiffness of a given system goes to zero, the resonance point also goes to zero RPM. With the freewheel clutch, the torsional frequency would go to zero whenever a torque reversal occurred For that moment in time, the RPM would then be above the resonance point and the engine would have no problem powering up into the operating RPM range. In this regard,the BD-5 soft system with the freewheel clutch was a passive dual frequency system, that functioned much like the active dual frequency system used in the Continenta Tiara family of geared aircraft engines FREEWHEEL CLUTCH - PARTIAL SOLUTION! It must be understood that the freewheel clutch is only part of the solution to the torsional resonance problem. Lowering the resonant point below the starting RPM of the engine is the other essential part of the solution. Simply installing a freewheel clutch in a system, where the torsional resonance point is still in the operating range, may give the appearance of success for the short term but not for the long term. In a low frequency, torsionally soft system like that developed at Bede, the clutch chatter frequency is low and the amplitude of rotational vibration is high, as the RPM passes through the resonance point. Also, this occurs at the point when the engine is just about to start and the energy level in the system is quite low. Exerpt from professional Rotorway operation and maintenance manual which contains detailed step by step instructions. This photo shows a setup for checking drive pulley run-out. A model publication for auto conversions It is true, the loads can be very high at the resonance point, but this occurs during a torque reversal which disengages the clutch and causes these loads to go to zero. These characteristics are good for long clutch life, which means a smaller clutch with a lower capacity is all that's required. This saves both weight and cost. On the other hand, in a higher frequency, torsionally hard system, the clutch chatter frequency is high and the amplitude of rotational vibration is low. With this type of system, the energy level is high. These characteristics tend to shorten clutch life. A system of this type will require a clutch with a much higher capacity, since torsional resonance is still a problem. The clutch and all other drive system components will then be subject to limited life considerations. I know of many who have tried using a freewheel clutch in a hard system as the solution to the torsional resonance problem, but I do not know any who have succeeded in the long term. For these reasons, I can not recommend the use of a freewheel clutch with a torsionally hard system 161 photos and 10 drawings throughout the manual fully illustrate the operation and maintenance of the RW133 engine. This picture suggests an acceptable method for installing the engine in the airframe. LATERAL VlBRATlON PROBLEMS Although we had solved the torsional vibration problem at Bede, lateral vibration problems still needed to be addressed. They had set up a test stand in an old gutted mobile home beside the Bede shop and the engine mechanic who was an expert in two-cycle engines was doing a lot of experimenting to improve the engine One day he and his assistant were working right beside the engine, in front of everything. The lower jackshaft was turning about 6000 RPM and he was adjusting the carburetors when he stepped aside slightly to get a wrench. All of a sudden there was a big explosion and a hole appeared in the wall of the test stand building. The lower jackshaft had broken loose from its rubber couplings and was hurled like a missile through the wall It travailed almost to the next building, nearly going through the wing of a Beech 18 and then burying itself in the Kansas gumbo mud. The energy involved was just unbelievable. If the mechanic had been standing where he had been just seconds before, he would have been killed. Once the system was put back together, we ran it with a strobe light on the jackstand. Immediately we saw that the lower jackshaft was not maintaining its concentricity with the engine crank on the forward end nor the sprocket on the aft end. The rubber couplings were too soft. The system was modified to use spherical bearings on each end to locate the lower jackshaft so it would not start this lateral vibration due to the centrifugal force acting on the shaft. This change solved this problem. There was also a lateral vibration problem with the lower sprocket. After hooking up the strobe light, we found the lower sprocket support was putting an undulating wave of vibration into the rear bulkhead of the engine compartment. This explained why all the rivets on the outside skin at that bulkhead were always coming loose. One day this vibration was particularly bad and we had Burt come by to take at look it. When he saw it, he just looked sort of shocked, turned whiteand went off mumbling something about not letting Les see this because we'll never get him to fly it again. I think it was at that point that he sort of gave up. This, along with the many other problems with the engine seemed to be the last straw as far as Burt was concerned. It was about a week or two later that both Burt and I left Bede Aircraft. Before my last day, I turned the design responsibility for the drive system over to our landing gear man, Al Thompson. I gave him instructions on how to redesign the lower sprocket mount. He did a superb job and the new mount solved the lateral resonance problem in the lower sprocket. ROTORWAY While at RotorWay, B.J. Schramm assigned me the job of designing and building a water dynamometer test stand for the RW 133 helicopter engine. The engine was mounted vertically, just like it was in the helicopter The dynamometer had a fairly heavy, high inertia rotor and was connected to the engine by a drive shaft with two universal joints. This test stand was used not only to develop the engine but to later fully test and run each customer's engine before delivery. The test stand was designed and built with a good appearance so that it could be used at Oshkosh and other airshows to demonstrate the engine, showing the actual torque and horsepower output to potential customers. One day, while testing the engine, all hell broke loose. The jackshaft with the two universals had broken off the engine and was flailing around, shaking the test stand quite violently. If I had been anywhere close, I would not be among the living today. We found that the upper part of the crankshaft had broken off. The break was all crystalline and it had the characteristics of a torsional fatigue failure. I mentioned to B.J. that the crank material sure looked strange. That was when I found out the crank was cast iron. The RotorWay engine was based on the Volkswagon engine but was highly modified to produce the power required for the helicopter. Although the volks engine had a forged crank, the RotorWay engine required a special crank with a long stroke. Since the engine was only in the development phase, B.J. used a cast iron crank. Soon aher this failure, B.J. had a new forged crank developed to replace the cast iron crank. One thing for sure, a cast iron crankshaft is not the best way to go, when trying to deal with torsional vibration. CLUTCH SPRING SOLUTION B.J. got in touch with the people who manufactured the dynamometer and found out that hooking a 4-cylinder engine to one of these dynos can be a problem. Any engine that produces 2 power strokes per revolution is bad news when it comes to torsional vibration, we were told. They suggested installing clutch springs, from an automobile clutch assembly, between the engine and the water dynamometer to solve this torsional problem. (This is the same idea Lou Ross uses on his gear boxes.) We also put a guard around the jackshaft so that if another failure occurred it would be contained I saw the test stand a few years ago and it appeared to be in good shape and still in use. The spring idea seemed to have worked out. DRIVE SYSTEM CONFIGURATIONS Any time a propeller is connected to an engine in any way other than directly to the crank it would be wise to realize that torsional vibration can be a problem. Basically, there are three propeller drive system configurations: 1. Propeller speed-reduction unit alone 2. Propeller speed-reduction unit with a shaft drive 3. Propeller shaft drive alone TORSIONAL RESONANCE FREQUENCY * Where k is the torsional spring constant, i.e. the torque (T) required to produce an angle of twist (a) of 1 radian in the shaft to which the propeller is attached. * Where d is the diameter of the propeller shaft. * Where G is the shearing modulus of elasticity of the shaft material * Where L is the length of the shaft in inches. * Where f is the frequency of the torsional vibration. * Where I is the mass moment of intertia at the propeller From the above formula it can be seen that: The torsional frequency can be lowered by: 1. Decreasing the diameter of the shaft(s) (d) 2. Decreasing the shearing modulus of elasticity of the shaft material (G) 3. Increasing the mass moment of intertia of the prop (l) 4. Increasing the length of the shaft (L) The torsional frequency can be raised by: 1. Increasing the diameter of the shaft(s) (d). 2. Increasing the shearing modulus of elasticity of the shaft material (G). 3. Decreasing the mass moment of interia of the prop (l). 4. Decreasing the length of the shaft (L). Torsional resonance frequency is affected, more or less, by the propeller, engine crankshaft, connecting rods, pistons, and every part in between such as a flywheel, gears, belts, and, to a lesser extent, the valve train and accessories. TYPES OF DRIVE SYSTEMS 1. A dampened system is one that uses a vibration damper to lower the resonant loads to more acceptable levels, while leaving the torsional resonance frequency within the operating RPM range of the engine. A dampened system can be used with a propeller speed-reduction unit and/or a drive shaft (i.e. Molt Taylor). 2. A hard drive is one that has a high torsional spring constant (k) and no slop from the propeller through to the engine crankshaft (maximum rigidity). The torsional problem is overcome strength and maximum stiffness. If a belt is used it should be tensioned as per manufacturer's recommendations. (i.e. Dave Blanton type bed drive system). A hard system becomes prohibitively heavy when used with a shaft drive because of the high torsional loads involved. 3. A soft system is one that has a low torsional spring constant (k) from the propeller through to the engine crankshaft so as to move the torsional resonance frequency below the operating RPM range and preferably below the starting RPM of the engine. A soft system, using a propeller speed-reduction unit alone (no driveshaft) with a sufficiently low torsional spring constant, would be difficult to design because of space, weight, and engineering limitations. A soft system with a drive shaft, if properly designed and tested, has the potential of being the lightest and most reliable of all the systems discussed (i.e. BD-5 belt/shaft drive system). DESIGN CRITERIA RECOMMENDATIONS 1. The more cylinders the better! 2. Engine Crankshaft: -1 st choice > forged - 2nd choice> machined billet - Not the best choice > cast iron 3. Joints in Rotating Parts: - Use joints that transfer torque by faction where possible (i.e. shrink, press &/or tapered fits) - Splines are not the best choice in hard systems. - If bolted joints (i e. flanged) are used, do not use the allowable bolt shear strength to carry the engine torque through the joint. Instead, size the bolts so that they can be tightened to produce sufficient bolt tension so the engine torque can be transferred through the joint by the resulting frictionbetween the flanges (Note: It would not be a ooodidea to have any bolt threads in the vicinity on thejoint.) 4. System Slop: - In a "hard system" (i.e. Dave Blanton hypesystem) avoid any slop in the system Use a beltwith proper tension as per manufacturersrecommendations. - In a 'soft system" (i.e. the BD-5 system) some slop can be tolerated. If a toothed belt (i.e. HTD) is used, it can be run loose. Also, gears and splines are less critical (i.e. the Continental Tiara aircraft engine). If a silent link type chain is used, chaint ension would be less cntical. 5. Torsional Spnng Constant of the System - In a "hard system" (i.e. Dave Blanton type system) the main design criteria should be to achieve a high torsional spring constant without adding excessive weight. The torsional problem is overcome by brute strength and maximum stiffness - In a "soft system" (i e. the BD-5 system) the main design criteria should be to achieve a low torsional spring constant while meeting the torque requirements of the engine with a moderate safety factor. The torsional spring constant should be low enough to move the torsional resonance frequency below the starting RPM of the engine. - The torsional spring constant can be lowered by decreasing the diameter of the shaft(s), decreasing the shearing modulus of elasticity of the shaft material, increasing the mass moment of inertia of the propeller and by increasing the length of the shaft(s). 6. Freewheel Clutch: - Use only a double cage, full phasing, sprag typec lutch. This type of clutch works well with a "soft system". - Roller and uncaged spring-loaded type freewheel clutches are not recommended. - It is not recommended to use a freewheel type clutch with a "hard system." The higher energy level of resonance, in this type of system, will eventually destroy the clutch, even though the engine RPM only passes through the resonance when going up to or down from the normal operating speed. 7. Cantilever Shafts: - Mounting overhung belt sprockets or gears on cantilevered shafts should be avoided, particularly on a "hard system". - If a design requires an overhung sprocket, keep the offset and the belt width to a minimum. SUMMARY BECOME FULLY INFORMED BEFORE TACKLING TORSIONALS! It would be advisable to develop a good base of knowledge before becoming too involved in torsional problems. Most intuitive solutions are the opposite of what should actually be done when torsional resonance is involved. It is my hope that this article will bring a degree of caution to experimenters and will encourage them to seek out more knowledge on the subject before they jump in and waste a lot of their time and money. Demonstration of torsional resonance effects. A 2x4 representing the inertia of a propeller is powered by a cordless drill motor through a 3/32 inch piano wire ("soft" system). One end of the rod is bent 90 degrees and stapled securely to the wood. Energy is applied by short, rapid trigger squeezes to simulate engine power pulses. Torsional effects are visual and are heard from the slippage of the shaft in the chuck and torque reversal clicking of the gears. ________________________________ Message 38 ____________________________________ Time: 09:01:53 PM PST US From: "Kolbdriver" Subject: Kolb-List: Long Sitting Rotax 582 --> Kolb-List message posted by: "Kolbdriver" Folks, It looks like I'm going to stay put for a while, I've landed in North Central Oklahoma and need to get back to building. Big Lar and I started about the same time, and I need to get busy so I can beat him in the air. I have a 582 that has been sitting for approx 4 yrs. I've religiously kept an equal mixture of seafoam, marvel mystery oil, opti 2, amsoil and penzoil for 2cycle in the cyl and pulled the prop thru several times a week to keep things lubed up. There seems to be good compression and no feeling of any kind of binding. Other than the obvious, replacing fuel pump and thoroughly cleaning the carbs what should I be changing, cleaning etc. prior to start up.?? It does have an oil injection system. Thanks, Mike (MK III C, she's still with me, lost 2 wives and 3 jobs in the process.) ________________________________ Message 39 ____________________________________ Time: 09:10:27 PM PST US From: "Chuck Stonex" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa --> Kolb-List message posted by: "Chuck Stonex" All of these stories from you former Challenger drivers are nice ..... I just wish one of you would come help me get into this M-III I'm lookin' at. Then I can be greatful that I bought a Kolb too! --> Kolb-List message posted by: "Billie Futrell" I would just like to add a little to what Woody has just said about a Challenger. I was going to buy a Challenger before I bought my Kolb. A friend of mine had a Challenger with the long wing so I flew with him for 3 hrs.I won't to tell you that was all I wanted. The first hr I was chasing the thing all over the sky. You want to make a correction to the left, so you give it aileron and it goes more to the right and then to the left. The second hr I figured out that you had to fly with rudder, and a lot of that and follow up with aileron. The only problem was before the hr was up I had cramps it the calves of my legs so bad I could hardly use my the rudder peddles. The third hr was not any better and when I left the field that day I knew I did not want a Challenger. I'm glad I go a kolb. Bill Futrell MK111Xtra912 Do not archive ----- Original Message ----- From: "woody" Subject: Re: Kolb-List: M-IIIC Drivers in Iowa > --> Kolb-List message posted by: "woody" > > I told him that if something happened like getting unexpectedly airborn > don't panic just fly the plane. He was a pilot but it still took him 3 > passes to figure out the right approach to land. No panic to get it back > down just kept flying untill he got things figured out. > Perhaps I am to used to Kolbs. Flying a Challenger was the most > frighteneing experience I had had in years. I was not prepared for the extra > rudder needed to stop a turn. These planes need rudder or it won't get out > of a turn, The extra stiff rudder pedals and lack of concern about rudders > in the Kolb had me circling for 10 minutes (felt like hours) trying to > figure out what to do next. Finally a hard kick to the rudders got some > movement and I straightened up. Quite frightening. I tried another > Challenger that day with the same result and need for rudder. Still could > not keep the nose from wandering around. I do understand the aircraft > exported to the UK have bigger rudders and may be less needy of rudder > input. > You're going to love the Kolb > > > ----- Original Message ----- > From: "PATRICK LADD" > To: > Subject: Re: Kolb-List: M-IIIC Drivers in Iowa > > > > --> Kolb-List message posted by: "PATRICK LADD" > > > > He didn't panic just remembered what I had told him>> > > > > Chuck, > > What did you tell him?. I am about to change from Challenger to Kolb and > > have not flown a tail dragger since I sold the Thruster many years ago. > > NB. The Challenger is not half as bad as this lot make out :-) > > > > Pat > > > > > > -- > > > > > > -- > > > > > > ________________________________ Message 40 ____________________________________ Time: 09:10:28 PM PST US From: "Richard Swiderski" Subject: RE: Kolb-List: VW reduction drive --> Kolb-List message posted by: "Richard Swiderski" VW Kolbers: I am installing a SPG-2 redrive on my 100hp 3 cyl chevy sprint turbo engine. I was talking with the North American distributor today & he commented that a guy in California put one on a VW using a simple aluminum adapter plate. This gearbox is commonly used on 3 & 4 cylinder Suzuki engines & Suburu engines up to 135 hp. They are imported out of Russia. Below is contact info if you are interested. -Richard Swiderski Regarding the SPG gearbox redrive the web site and contact is: Vassili Tarakanov, Aerospace Engineer Canadian UL Instructor Air Trikes Enterprises Manager www.airtrikes.net Phone/fax (514) 685-2856 ________________________________ Message 41 ____________________________________ Time: 09:20:27 PM PST US From: "Larry Bourne" Subject: Re: Kolb-List: Long Sitting Rotax 582 --> Kolb-List message posted by: "Larry Bourne" What ?? You mean there's another record un-setter in the crowd ?? I just got in from a 3 1/2 week vacation to the *cool* wilds of British Columbia, Canada tonight, and had been having great delusions of jumping back into the Vamoose fray and getting it finished off. Hah ! ! ! At 7:30 PM it was still 108 outside. Digital thermometer in the house only goes to 99, and it took an hour and 5 minutes for it to drop to 98. This with an oversized A/C unit. Now, at 9:15, it's down to 90 and feels positively cool. :-( I now hae me doots about working on anything, but we'll see. Slow Cookin' Lar. Do not Archive. Larry Bourne Palm Springs, CA Building Kolb Mk III N78LB Vamoose www.gogittum.com ----- Original Message ----- From: "Kolbdriver" Subject: Kolb-List: Long Sitting Rotax 582 > --> Kolb-List message posted by: "Kolbdriver" > > Folks, > > > It looks like I'm going to stay put for a while, I've landed in North > Central Oklahoma and need to get back to building. Big Lar and I started > about the same time, and I need to get busy so I can beat him in the air. > > > I have a 582 that has been sitting for approx 4 yrs. I've religiously > kept > an equal mixture of seafoam, marvel mystery oil, opti 2, amsoil and > penzoil > for 2cycle in the cyl and pulled the prop thru several times a week to > keep > things lubed up. There seems to be good compression and no feeling of any > kind of binding. > > > Other than the obvious, replacing fuel pump and thoroughly cleaning the > carbs what should I be changing, cleaning etc. prior to start up.?? > > It does have an oil injection system. > > > Thanks, > > Mike (MK III C, she's still with me, lost 2 wives and 3 jobs in the > process.) > > >