---------------------------------------------------------- Zenith-List Digest Archive --- Total Messages Posted Thu 10/23/03: 21 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:43 AM - Crash 701 (Bob Miller) 2. 06:05 AM - Re: Crash 701 (David Barth) 3. 07:12 AM - Re: Crash 701 (Flydog1966@aol.com) 4. 12:19 PM - Re: Crash 701 (Weston, Jim) 5. 01:28 PM - Rotax throttle control (H. Robert Schoenberger) 6. 02:05 PM - Re: Crash 701 (HINDE,FRANK (HP-Corvallis,ex1)) 7. 02:57 PM - Re: Rotax throttle control () 8. 03:08 PM - Re: Crash 701 (Jon Croke) 9. 03:08 PM - Re: Rotax throttle control (HINDE,FRANK (HP-Corvallis,ex1)) 10. 03:08 PM - Re: Rotax throttle control (Larry McFarland) 11. 04:19 PM - 701 throttle (ZSMITH3rd@aol.com) 12. 04:22 PM - Thanks (Brandon Tucker) 13. 04:27 PM - Re: Thanks (Dave Pepper) 14. 04:33 PM - Re: Rotax throttle control (Gary Gower) 15. 05:10 PM - Re: Crash 701 (Gary Gower) 16. 05:58 PM - Re: Crash 701 (Wayne McIntosh) 17. 08:05 PM - Re: Crash 701 (Chesterman Family) 18. 08:31 PM - Re: Crash 701 (Bruce Bockius) 19. 10:22 PM - Re: Rotax throttle control (barry mayne) 20. 10:29 PM - Re: Crash 701 (Brenton Battles) 21. 10:55 PM - Re: Crash 701 (Gary Gower) ________________________________ Message 1 _____________________________________ Time: 04:43:40 AM PST US From: "Bob Miller" Subject: Zenith-List: Crash 701 --> Zenith-List message posted by: "Bob Miller" Jon, I want to thank you for your accident report, as that is EXACTLY the kind of thing I might have done. Your report may well have saved some lives. Please get over the embarrassment--you handled the airplane properly or you would have been killed. Bob Miller ________________________________ Message 2 _____________________________________ Time: 06:05:10 AM PST US From: David Barth Subject: Re: Zenith-List: Crash 701 --> Zenith-List message posted by: David Barth Jon. Thank you so very much for sharing your "embarrassing" story with us. It has to be tough to write about but it could very well be that your sharing of this story might prevent the loss of lives. Glad you are OK. You have a great attitude and I am glad you will be getting back on the building train. Thanks again for sharing. David Do Not Archive > The cat is out of the bag! I was laying low about > this incident because I > am so EMBARASSED about what happened! > ===== David Barth 601 XL Plansbuilder Still making parts. Nose Ribs Done and about half the rear ribs for the wings. Stab and elevator waiting for skins. Flaps, ailerons and Rudder ready for inspection. __________________________________ ________________________________ Message 3 _____________________________________ Time: 07:12:21 AM PST US From: Flydog1966@aol.com Subject: Re: Zenith-List: Crash 701 --> Zenith-List message posted by: Flydog1966@aol.com In a message dated 10/22/03 9:33:02 PM Eastern Daylight Time, Jon@joncroke.com writes: << only went to about 4000 rpm, instead of 5200 or so. She just barely made it over the high tension wires at the end of my strip and really wasnt climbing much at this engine speed. >> Thanks for the report Jon, it is valuable to prevent anyone else(me!) from doing the same. I do have a couple questions . Is'nt the Rotax 912 making enough horsepower @4000 rpm to fly? Anybody on the list know the h.p.@ 4000rpm? I think the proto-type 701 was flying with a 53 hp Rotax 503. Also, If the plane"really was'nt climbing much at this speed" , sounds like it was climbing....why did it descend into the trees? But anyway, you did a fine job , kept your cool,and flew it all the way to the ground...er..tree tops. Keep up the positive out look,and have fun building the next even better! Phil ________________________________ Message 4 _____________________________________ Time: 12:19:08 PM PST US Subject: RE: Zenith-List: Crash 701 From: "Weston, Jim" --> Zenith-List message posted by: "Weston, Jim" Jon, Great attitude, and very responsible of you to pass on this important info. Even though it was embarrassing. By the way, don't be embarrassed. I'll bet a months salary that everyone on this list has made a mistake or two in life. BTW, I have a Stratus Subaru on a 601HDS and your experience still applies, since I have the same carburetor arrangement. Jim Weston McDonough, Ga -----Original Message----- From: Jon Croke [mailto:Jon@joncroke.com] Subject: Zenith-List: Crash 701 --> Zenith-List message posted by: "Jon Croke" > Just read an NTSB report about an accident with your airplane. Hope > you are ok ________________________________ Message 5 _____________________________________ Time: 01:28:04 PM PST US From: "H. Robert Schoenberger" Subject: Zenith-List: Rotax throttle control --> Zenith-List message posted by: "H. Robert Schoenberger" List . . . I've been following the details of Jon's accident. He's a great guy - always willing to answer my construction questions. I'm just thankful that he wasn't injuried or killed. I'm far from installing the engine on my 701, but have a curiosity question as to why the Rotax throttle assembly is as it is. As I understand the situation from Jon's explanation, when you apply full throttle it is the spring which opens the carb and not the cable. What happens if the spring breaks in flight, particularly on takeoff? I was always taught that fail safe is best but this does not seem to be the case here. Hap Schoenberger 701 tail done, working on right wing ________________________________ Message 6 _____________________________________ Time: 02:05:22 PM PST US From: "HINDE,FRANK (HP-Corvallis,ex1)" Subject: RE: Zenith-List: Crash 701 --> Zenith-List message posted by: "HINDE,FRANK (HP-Corvallis,ex1)" Ya...as soon as I saw Jon's reply it had me thinking if I could replace the cable with a solid push/pull rod direct to the carbs. It was just so sad that the engine vibration did not shake the throttles open and you had found the issue further away from the ground. Frank 601HDS Stratus with Ram heads -----Original Message----- From: owner-zenith-list-server@matronics.com [mailto:owner-zenith-list-server@matronics.com] On Behalf Of Weston, Jim Subject: RE: Zenith-List: Crash 701 --> Zenith-List message posted by: "Weston, Jim" Jon, Great attitude, and very responsible of you to pass on this important info. Even though it was embarrassing. By the way, don't be embarrassed. I'll bet a months salary that everyone on this list has made a mistake or two in life. BTW, I have a Stratus Subaru on a 601HDS and your experience still applies, since I have the same carburetor arrangement. Jim Weston McDonough, Ga -----Original Message----- From: Jon Croke [mailto:Jon@joncroke.com] Subject: Zenith-List: Crash 701 --> Zenith-List message posted by: "Jon Croke" > Just read an NTSB report about an accident with your airplane. Hope > you are ok ________________________________ Message 7 _____________________________________ Time: 02:57:57 PM PST US Subject: RE: Zenith-List: Rotax throttle control From: --> Zenith-List message posted by: There are a LOT of Rotax engines flying; don't get too creative on how they "ought to work". The strong springs will give you power if you allow them to. 400+ hours on my 912S and no issues. GGP ________________________________ Message 8 _____________________________________ Time: 03:08:02 PM PST US From: "Jon Croke" Subject: Re: Zenith-List: Crash 701 --> Zenith-List message posted by: "Jon Croke" Actually, it is not accurate to say that it descended into the trees. I was about 10' off the runway when I applied full power from my go-around and got 4000 rpm or less; then JUST crossed above the power lines at about 25' ; then couldnt quite make it to about 50' when the trees arrived in my path. So, I WAS climbing but way too little.... my gear caught the top of the trees and they sucked me in! I beleive that 4000 rpm is enough for cruise straight and level, and very little climb. Good question about the performance in the days of the Rotax 503 (52 hp)! Probably was less than spectacular performance? > --> Zenith-List message posted by: Flydog1966@aol.com > > In a message dated 10/22/03 9:33:02 PM Eastern Daylight Time, > Jon@joncroke.com writes: > > << only went to about 4000 rpm, instead of 5200 or so. She just barely made > it > over the high tension wires at the end of my strip and really wasnt climbing > much at this engine speed. >> >Is'nt the Rotax 912 making > enough horsepower @4000 rpm to fly? Anybody on the list know the h.p.@ 4000rpm? > I think the proto-type 701 was flying with a 53 hp Rotax 503. Also, If the > plane"really was'nt climbing much at this speed" , sounds like it was > climbing....why did it descend into the trees? ________________________________ Message 9 _____________________________________ Time: 03:08:03 PM PST US From: "HINDE,FRANK (HP-Corvallis,ex1)" Subject: RE: Zenith-List: Rotax throttle control --> Zenith-List message posted by: "HINDE,FRANK (HP-Corvallis,ex1)" If a spring breaks on TO the throttle will be fully open anyway so no problem. Frank -----Original Message----- From: owner-zenith-list-server@matronics.com [mailto:owner-zenith-list-server@matronics.com] On Behalf Of H. Robert Schoenberger Subject: Zenith-List: Rotax throttle control --> Zenith-List message posted by: "H. Robert Schoenberger" --> List . . . I've been following the details of Jon's accident. He's a great guy - always willing to answer my construction questions. I'm just thankful that he wasn't injuried or killed. I'm far from installing the engine on my 701, but have a curiosity question as to why the Rotax throttle assembly is as it is. As I understand the situation from Jon's explanation, when you apply full throttle it is the spring which opens the carb and not the cable. What happens if the spring breaks in flight, particularly on takeoff? I was always taught that fail safe is best but this does not seem to be the case here. Hap Schoenberger 701 tail done, working on right wing advertising on the Matronics Forums. ________________________________ Message 10 ____________________________________ Time: 03:08:35 PM PST US From: "Larry McFarland" Subject: Re: Zenith-List: Rotax throttle control --> Zenith-List message posted by: "Larry McFarland" As I understand the situation from Jon's explanation, when you apply full throttle it is the spring which opens the carb and not the cable. What happens if the spring breaks in flight, particularly on takeoff? Hap, This problem is an awkward design which was carried into the 601s as well. I changed my Stratus to a solid wire and connecting link between carbs, despite their angle to eah other. Just couldn't bear to leave such a critical operational element to springs. Larry McFarland ________________________________ Message 11 ____________________________________ Time: 04:19:17 PM PST US From: ZSMITH3rd@aol.com Subject: Zenith-List: 701 throttle --> Zenith-List message posted by: ZSMITH3rd@aol.com Another way of understanding the 912 throttle spring arrangement: The springs keep the carburetors WIDE OPEN. The throttle, that thing sticking through the instrument panel, is used to CLOSE the carbs by PULLING it rearward. When you PUSH it, as in the 701, you are allowing the springs to PULL the carbs into a more-open position. There is a "friction block" which you, the throttle operator, and they, the springs, work against. The builder adjusts this item. The idea here is that if your throttle rods all fall off, you will have a wide-open, balls-to-the-wall power plant. The mag switches then become your engine speed control. But at least you'll have power. Hope this adds some measure clarity to the issue. Zed Smith/701/R912/90% there, 90% to go. DO NOT ARCHIVE ________________________________ Message 12 ____________________________________ Time: 04:22:44 PM PST US From: Brandon Tucker Subject: Zenith-List: Thanks --> Zenith-List message posted by: Brandon Tucker Jon, Thanks for sharing your story. Your intelligence and great attitude is a tribute to the kind of people on this list. Respectfully, Brandon Tucker 601 HDS Starting on wings Do not archive __________________________________ ________________________________ Message 13 ____________________________________ Time: 04:27:26 PM PST US From: "Dave Pepper" Subject: Re: Zenith-List: Thanks --> Zenith-List message posted by: "Dave Pepper" It's great that we can all learn from each other's trials and tribulations. Thanks. Dave Pepper 601HD/912S 90% > Jon, > > Thanks for sharing your story. Your intelligence > and great attitude is a tribute to the kind of people > on this list. > > > Respectfully, > > Brandon Tucker > 601 HDS > Starting on wings > > Do not archive > > __________________________________ > > ________________________________ Message 14 ____________________________________ Time: 04:33:45 PM PST US From: Gary Gower Subject: Re: Zenith-List: Rotax throttle control --> Zenith-List message posted by: Gary Gower We had the same thoughts a week ago, our idea was for the posibility of the springs to fail... So we made a simple "backup" without modifying the Rotax highly enginered idea (in fact is a good one, has worked OK for years)... We added a little of "liquid rubber" to the end of the cables where they go through the bolt... Is the rubber they sell in little cans to use in tools handles. Is very strong and doesnt interfear with the movement of the bolt or the cables. I will post a photo in the photoshare. A photo is better than 1.000 words... Yes, in the photo you will also see the modified angle, is only for aesthetics, has an angle from the firewall to the lower part of the 7-F7-1SP channel, works the same but is more "aircraft look". I have no time to load more photos to my photo page, I will try to load only the modified ones... Saludos Gary Gower --- "H. Robert Schoenberger" wrote: > --> Zenith-List message posted by: "H. Robert Schoenberger" > > > List . . . I've been following the details of Jon's accident. He's a > great guy - always willing to answer my construction questions. I'm > just thankful that he wasn't injuried or killed. > > I'm far from installing the engine on my 701, but have a curiosity > question as to why the Rotax throttle assembly is as it is. As I > understand the situation from Jon's explanation, when you apply full > throttle it is the spring which opens the carb and not the cable. > What happens if the spring breaks in flight, particularly on takeoff? > I was always taught that fail safe is best but this does not seem to > be the case here. Hap Schoenberger 701 tail done, working on right > wing > > > > > > > > __________________________________ ________________________________ Message 15 ____________________________________ Time: 05:10:03 PM PST US From: Gary Gower Subject: Re: Zenith-List: Crash 701 --> Zenith-List message posted by: Gary Gower Hi Jon, I am really glad you made it, I had a crash landing in one of my ultralights some time ago and also got out without a scratch, That brings a very special love to the plane that saved our live... Yes, I fully rebuilt that one and still keep it and fly it. I have two comments: (I know this one will bring up a discussion (hopefully we can come out with something good about it) One is if your engine was stoped by branches, probabbly the "strike" was not too hard and more kind of progressive, what ruins the crankshaft is with the floor or any hard object like the tree wood, because it stops with a single Bang! Dont know what is needed to check your engine... probably she is sound and safe like you. Another one: The 701 prototype had less weight that the ones we are building now (if we can believe it can be built lighter). The preformance was almost in the "critical" side. If you have the ZAC Demo Video, there is one with a 503 in a longer take off over some houses, I think in Africa... That is an example. The 912 gave a new life and personality to this airplanes, the "look" remained the same... this ugly beauty :-) Saludos Gary Gower --- Jon Croke wrote: > --> Zenith-List message posted by: "Jon Croke" > > > Actually, it is not accurate to say that it descended into the trees. > I was > about 10' off the runway when I applied full power from my go-around > and got > 4000 rpm or less; then JUST crossed above the power lines at about > 25' ; > then couldnt quite make it to about 50' when the trees arrived in my > path. > So, I WAS climbing but way too little.... my gear caught the top of > the > trees and they sucked me in! I beleive that 4000 rpm is enough for > cruise > straight and level, and very little climb. Good question about the > performance in the days of the Rotax 503 (52 hp)! Probably was less > than > spectacular performance? > > > --> Zenith-List message posted by: Flydog1966@aol.com > > > > In a message dated 10/22/03 9:33:02 PM Eastern Daylight Time, > > Jon@joncroke.com writes: > > > > << only went to about 4000 rpm, instead of 5200 or so. She just > barely > made > > it > > over the high tension wires at the end of my strip and really > wasnt > climbing > > much at this engine speed. >> > > >Is'nt the Rotax 912 making > > enough horsepower @4000 rpm to fly? Anybody on the list know the > h.p.@ > 4000rpm? > > I think the proto-type 701 was flying with a 53 hp Rotax 503. > Also, If > the > > plane"really was'nt climbing much at this speed" , sounds like it > was > > climbing....why did it descend into the trees? > > > > > > > > __________________________________ ________________________________ Message 16 ____________________________________ Time: 05:58:20 PM PST US From: "Wayne McIntosh" Subject: Re: Zenith-List: Crash 701 --> Zenith-List message posted by: "Wayne McIntosh" Phil, If you look at the published Rotax data you will find that a 80 HP rotax 912 at 4000RPM is putting out 58 horsepower. But that data is for an engine running at full throttle. Jon was not at full throttle so he was way less than the 58 horsepower. Also his prop was pitched to his normal takeoff/cruise rpm. Many 912's have a reduction of 2.27:1 so at say 5800 RPM the prop is pitched to absorb 80 horsepower at 2500 propeller RPM and convert the 80 horsepower into enough thrust to climb. But at 4000RPM at part throttle with the same prop pitch and the propeller turning only 1750 RPM there just was not enough thrust to make a climb. If Jon had been a little luckier and had another 200 RPM and the trees were 5 feet shorter things may have been different. Jon definitely has "True Grit", thanks for telling us your story. Wayne McIntosh Lafayette, IN ----- Original Message ----- From: Subject: Re: Zenith-List: Crash 701 > > << only went to about 4000 rpm, instead of 5200 or so. She just barely made > it > over the high tension wires at the end of my strip and really wasnt climbing > much at this engine speed. >> > > Thanks for the report Jon, it is valuable to prevent anyone else(me!) from > doing the same. I do have a couple questions . Is'nt the Rotax 912 making > enough horsepower @4000 rpm to fly? Anybody on the list know the h.p.@ 4000rpm? > I think the proto-type 701 was flying with a 53 hp Rotax 503. Also, If the > plane"really was'nt climbing much at this speed" , sounds like it was > climbing....why did it descend into the trees? > But anyway, you did a fine job , kept your cool,and flew it all the > way to the > ground...er..tree tops. Keep up the positive out look,and have fun building > the next even better! > Phil > > ________________________________ Message 17 ____________________________________ Time: 08:05:07 PM PST US From: Chesterman Family Subject: Re: Zenith-List: Crash 701 --> Zenith-List message posted by: Chesterman Family My 701 has the 582 so I can't say about rpm and sufficient lift but 1/2 or all flap would have slowed your ground speed and may have given you the extra 5' you needed. Maybe I overpitched my prop once when installing a new GSC and when your plane lacks power it sure makes you sweat. Dave Chesterman701 flying since 1997 > --> Zenith-List message posted by: "Jon Croke" > > Actually, it is not accurate to say that it descended into the trees. I was > about 10' off the runway when I applied full power from my go-around and got > 4000 rpm or less; then JUST crossed above the power lines at about 25' ; > then couldnt quite make it to about 50' when the trees arrived in my path. > So, ________________________________ Message 18 ____________________________________ Time: 08:31:43 PM PST US From: "Bruce Bockius" Subject: RE: Zenith-List: Crash 701 --> Zenith-List message posted by: "Bruce Bockius" > --> Zenith-List message posted by: "HINDE,FRANK (HP-Corvallis,ex1)" > --> > > Ya...as soon as I saw Jon's reply it had me thinking if I > could replace the cable with a solid push/pull rod direct to > the carbs. > > It was just so sad that the engine vibration did not shake > the throttles open and you had found the issue further away > from the ground. > I didn't like ZAC's setup (same problem, springs pulled throttle open unless the friction lock was too tight for my liking) and replaced mine when building with solid push-pull wires ($5 at an auto parts store - the standard lawn mower throttle cable) and removed the springs. Yes, I understand that most a/c engines are spring loaded to full throttle as a safety feature, and that I have defeated this. It is unclear to me that a broken push-pull wire is more likely than a broken spring, however. It has worked now for 400+ hours. -Bruce/601HD/TDO/Stratus (which has same carbs & throttle setup as a Rotax) Bruce Bockius Black Forest, CO, USA bruce@WhiteAntelopeSoftware.com http://www.WhiteAntelopeSoftware.com/zodiac ________________________________ Message 19 ____________________________________ Time: 10:22:44 PM PST US From: barry mayne Subject: Re: Zenith-List: Rotax throttle control --> Zenith-List message posted by: barry mayne G'day all, Aircraft carbies are by design to be throttle open in the passive state ( no throttle cable attached ). The reasoning is that if a throttle cable or linkage breakes you will have full power. It is considered that a cable is much more likely to break than a fairly robust spring. Congrulations to Jon on keeping cool, and explaining his mistake. Barry Mayne ----- Original Message ----- From: "H. Robert Schoenberger" Subject: Zenith-List: Rotax throttle control > --> Zenith-List message posted by: "H. Robert Schoenberger" > > List . . . I've been following the details of Jon's accident. He's a great guy - always willing to answer my construction questions. I'm just thankful that he wasn't injuried or killed. > > I'm far from installing the engine on my 701, but have a curiosity question as to why the Rotax throttle assembly is as it is. As I understand the situation from Jon's explanation, when you apply full throttle it is the spring which opens the carb and not the cable. What happens if the spring breaks in flight, particularly on takeoff? I was always taught that fail safe is best but this does not seem to be the case here. Hap Schoenberger 701 tail done, working on right wing > > ________________________________ Message 20 ____________________________________ Time: 10:29:32 PM PST US Subject: Re: Zenith-List: Crash 701 From: Brenton Battles --> Zenith-List message posted by: Brenton Battles John, I was really sorry to hear of your mishap but very relieved to know you came out unscathed! When you were here flying with me I think I mentioned how my confidence in my 601 had grown over time from the days when I was concerned about it's low glide ratio in an engine-out situation to my current realization that one doesn't need too much space to put the airplane down and once down, the energy dissipates rapidly. Your experience also confirms my speculation that the well-designed structure would typically absorb a great deal of energy in any impact which would tend to protect the occupants. Sorry to have this confirmed by your misfortune, but you've added a lot to your fellow builders' and fliers' insight by being so candid and thorough in writing about what went wrong. I hope you'll maintain your energies and optimism as you rebuild. Keep us informed and we'll be rooting for you. Regards, Brent Battles ________________________________ Message 21 ____________________________________ Time: 10:55:17 PM PST US From: Gary Gower Subject: RE: Zenith-List: Crash 701 --> Zenith-List message posted by: Gary Gower Bruce: Here I go, I dont want to be a "bad new teller", I normally dont make "no positive" comments, BUT this one I consider important: Solid cables are more prone to fail that flexible multicables (sp?) mainly by vibration or as the genius say harmonic resonance :-)... The only point in favor of the solid cables are that they dont bend in pushing, If you want to keep the solid cables, is OK, maybe they will never fail, but if it was my plane I will put the springs back, even the springs from the VW air cooled car's carburator are the same size but less strong, give them a look... When a carburator is not opening... I can remember one of my emergency landings with my old faithfull 503: When I aplyed power to climb, the engine maked a Vrrroooo sound (because one cable broked) and no power... open my eyes wide to look for that little clear spot and nail it... sure brings adrenaline out and a big smile once I got off the unharmed plane (ultralight)... The 601 has a little faster landing speed, need more clear space and cero rocks or bushes to make it... Sorry, just needed to tell you this. Saludos Gary Gower. --- Bruce Bockius wrote: > --> Zenith-List message posted by: "Bruce Bockius" > > > > --> Zenith-List message posted by: "HINDE,FRANK (HP-Corvallis,ex1)" > > > --> > > > > Ya...as soon as I saw Jon's reply it had me thinking if I > > could replace the cable with a solid push/pull rod direct to > > the carbs. > > > > It was just so sad that the engine vibration did not shake > > the throttles open and you had found the issue further away > > from the ground. > > > > I didn't like ZAC's setup (same problem, springs pulled throttle > open > unless the friction lock was too tight for my liking) and replaced > mine > when building with solid push-pull wires ($5 at an auto parts store - > the standard lawn mower throttle cable) and removed the springs. > Yes, I > understand that most a/c engines are spring loaded to full throttle > as a > safety feature, and that I have defeated this. It is unclear to me > that > a broken push-pull wire is more likely than a broken spring, however. > It has worked now for 400+ hours. > > -Bruce/601HD/TDO/Stratus (which has same carbs & throttle setup as > a > Rotax) > > Bruce Bockius > Black Forest, CO, USA > bruce@WhiteAntelopeSoftware.com > http://www.WhiteAntelopeSoftware.com/zodiac > > > > > > > > __________________________________