---------------------------------------------------------- Kolb-List Digest Archive --- Total Messages Posted Fri 10/24/03: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:22 AM - Re: Vortex Generators (Thom Riddle) 2. 06:58 AM - Re: Vortex Generators (Bob Bean) 3. 07:47 AM - Re: Vortex Generators (Richard Pike) 4. 12:25 PM - Re: Vortex Generators (Ben Ransom) 5. 12:48 PM - 2SI gearbox service () 6. 01:33 PM - Re: 2SI gearbox service (Olenik Aviation) 7. 02:24 PM - Re: Vortex Generators (kuffel) 8. 02:27 PM - Re: Vortex Generators update - success! (HShack@aol.com) 9. 03:31 PM - Re: 2SI gearbox service () 10. 04:17 PM - 912S Hi Torque Starter and Slip Clutch (John Hauck) 11. 04:26 PM - Medical (Paul Petty) 12. 05:35 PM - 912S starter and slipper clutch upgrade (Erich_Weaver@URSCorp.com) 13. 07:15 PM - Re: 2SI gearbox service (Don Gherardini) ________________________________ Message 1 _____________________________________ Time: 06:22:19 AM PST US From: "Thom Riddle" Subject: Re: Kolb-List: Vortex Generators --> Kolb-List message posted by: "Thom Riddle" I have made my VGs but not yet installed them on the 84FS377. My goal is to reduce landing and take-off speed to a minimum. My quandary is this. Since the short legs on the aircraft preclude a full stall angle of attack in 3 point stance, does it make sense to install the VGs at the separation point at full-stall angle of attack or at the 3-point angle of attack? The only way I know of estimating these separation points is by finding the top of the airfoil at the angle of attack under these two different conditions and assuming the separation point is slightly behind that. Based on the reading I've done, these airfoils tend to stall at approximately 14-16 degrees AOA and normal cruise is around 4-6 degrees, so if this is correct, then we are only dealing with an AOA range of 10-12 degrees. I have fabricated a simple angle of attack gauge and will install this hoping to verify current AOAs under different conditions before VGs and then again after installing the VGs. I have read most of the archives on VGs but still don't know the best location for the VGs for minimizing the take-off and landing speed in ground effect. Any insight will be appreciated. Thom Riddle 84FS377 ________________________________ Message 2 _____________________________________ Time: 06:58:42 AM PST US From: Bob Bean Subject: Re: Kolb-List: Vortex Generators --> Kolb-List message posted by: Bob Bean Thom, to further confuse the issue.....I noticed in the recent "custom planes" an article on stc'd vgs for a late model taylorcraft. They were located very far up front. The price was pretty steep too for a handful of aluminum strips. -BB do not archive Thom Riddle wrote: >--> Kolb-List message posted by: "Thom Riddle" > >I have made my VGs but not yet installed them on the 84FS377. My goal is to >reduce landing and take-off speed to a minimum. > >My quandary is this. Since the short legs on the aircraft preclude a full >stall angle of attack in 3 point stance, does it make sense to install the >VGs at the separation point at full-stall angle of attack or at the 3-point >angle of attack? The only way I know of estimating these separation points >is by finding the top of the airfoil at the angle of attack under these two >different conditions and assuming the separation point is slightly behind >that. > >Based on the reading I've done, these airfoils tend to stall at >approximately 14-16 degrees AOA and normal cruise is around 4-6 degrees, so >if this is correct, then we are only dealing with an AOA range of 10-12 >degrees. I have fabricated a simple angle of attack gauge and will install >this hoping to verify current AOAs under different conditions before VGs and >then again after installing the VGs. > >I have read most of the archives on VGs but still don't know the best >location for the VGs for minimizing the take-off and landing speed in ground >effect. Any insight will be appreciated. > >Thom Riddle >84FS377 > > > > ________________________________ Message 3 _____________________________________ Time: 07:47:20 AM PST US From: Richard Pike Subject: Re: Kolb-List: Vortex Generators --> Kolb-List message posted by: Richard Pike I like Jack Hart's method of flying the airplane off in ground effect and noting the airspeed. Tape your vg's on and do it again, note the airspeed. Try them further forward and then back and see how it flies just above touchdown in ground effect, and you will hit the sweet spot. Besides, it's fun flying down a long grass runway at slow speeds in ground effect, you can have fun during the tests. Richard Pike MKIII N420P (420ldPoops) At 09:22 AM 10/24/03 -0400, you wrote: >--> Kolb-List message posted by: "Thom Riddle" > >I have made my VGs but not yet installed them on the 84FS377. My goal is to >reduce landing and take-off speed to a minimum. > > >I have read most of the archives on VGs but still don't know the best >location for the VGs for minimizing the take-off and landing speed in ground >effect. Any insight will be appreciated. > >Thom Riddle >84FS377 > > ________________________________ Message 4 _____________________________________ Time: 12:25:00 PM PST US From: Ben Ransom Subject: Re: Kolb-List: Vortex Generators --> Kolb-List message posted by: Ben Ransom Thom, You might be making this more complicated than necessary. How do you really know you would want the VGs located at the "point of separation" anyway? [on the theoretical side I would think the vgs would need to be in front of that point.] And, of course that point will change when you put the vgs on. I'd pick the location used by others, flight test, relocate, etc. As Richard says -- a great bit of fun in itself. -Ben --- Thom Riddle wrote: > --> Kolb-List message posted by: "Thom Riddle" > > > I have made my VGs but not yet installed them on the 84FS377. My > goal is to > reduce landing and take-off speed to a minimum. > > My quandary is this. Since the short legs on the aircraft preclude a > full > stall angle of attack in 3 point stance, does it make sense to > install the > VGs at the separation point at full-stall angle of attack or at the > 3-point > angle of attack? The only way I know of estimating these separation > points > is by finding the top of the airfoil at the angle of attack under > these two > different conditions and assuming the separation point is slightly > behind > that. > > Based on the reading I've done, these airfoils tend to stall at > approximately 14-16 degrees AOA and normal cruise is around 4-6 > degrees, so > if this is correct, then we are only dealing with an AOA range of > 10-12 > degrees. I have fabricated a simple angle of attack gauge and will > install > this hoping to verify current AOAs under different conditions before > VGs and > then again after installing the VGs. > > I have read most of the archives on VGs but still don't know the best > location for the VGs for minimizing the take-off and landing speed in > ground > effect. Any insight will be appreciated. > > Thom Riddle > 84FS377 > > > > > > > > ===== http://mae.ucdavis.edu/~ransom __________________________________ ________________________________ Message 5 _____________________________________ Time: 12:48:41 PM PST US From: Subject: Kolb-List: 2SI gearbox service --> Kolb-List message posted by: Kolbers, I got my GB-1 gearbox together yesterday with new seals. They cost a grand total of $13.11 delivered from ZDE. I used Yamabond sealant when I reassembled the gearbox and after letting it set up overnight I installed it and prop today and took a couple trips around the pattern to test out the job before venturing away from the airport. Whew Wee do these things ever climb on cool buoyant days, the VSI bounced between 1100 and 1700 FPM and I was at 600 AGL before I crossed the numbers on both take offs. After the second landing, I parked on the taxiway and jumped out to check for leaks. DRATS! found that I must have had a void in the bead of Yamabond around the top front aluminum seal plate and I was loosing a little gear oil. Pulled it back off and will tear it down clean it up and try again tonight with high temp silicon instead of Yamabond. Man it is nice out and I was hoping to put a couple hours on her today. Maybe tomorrow. Dennis Rowe, Mk-3, PA ________________________________ Message 6 _____________________________________ Time: 01:33:20 PM PST US From: "Olenik Aviation" Subject: RE: Kolb-List: 2SI gearbox service --> Kolb-List message posted by: "Olenik Aviation" Denny, It's probably coming from that vent....plug it with some RTV. Otherwise it will always leak a little gear lube. Not much, but a little looks like a lot when the air is smearing it around. Tom Olenik Olenik Aviation http://www.buyitsellitfixit.com -----Original Message----- From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com]On Behalf Of rowedl@highstream.net Subject: Kolb-List: 2SI gearbox service --> Kolb-List message posted by: Kolbers, I got my GB-1 gearbox together yesterday with new seals. They cost a grand total of $13.11 delivered from ZDE. I used Yamabond sealant when I reassembled the gearbox and after letting it set up overnight I installed it and prop today and took a couple trips around the pattern to test out the job before venturing away from the airport. Whew Wee do these things ever climb on cool buoyant days, the VSI bounced between 1100 and 1700 FPM and I was at 600 AGL before I crossed the numbers on both take offs. After the second landing, I parked on the taxiway and jumped out to check for leaks. DRATS! found that I must have had a void in the bead of Yamabond around the top front aluminum seal plate and I was loosing a little gear oil. Pulled it back off and will tear it down clean it up and try again tonight with high temp silicon instead of Yamabond. Man it is nice out and I was hoping to put a couple hours on her today. Maybe tomorrow. Dennis Rowe, Mk-3, PA ________________________________ Message 7 _____________________________________ Time: 02:24:34 PM PST US From: kuffel Subject: Re: Kolb-List: Vortex Generators --> Kolb-List message posted by: kuffel Thom, <> The official answer according to the NACA/NASA Technical Reports I've read over the years is to place VGs so the vortexes they generate are just tangent to each other at the trailing edge at stall. And there is a modest tradeoff between number of VGs and chordwise location. Unfortunately, determining when the vortices are tangent requires a wind tunnel with smoke or extensive tuft testing. It is a lot easier to set the number of VGs by other considerations such as rib location and determine the chordwise location in flight test. Personally, I would do this flight testing at altitude and use IAS and controllability as my guide. Then the tail wheel will tell you if you need longer gear legs for maximum performance 3-point landings by consistently hitting the runway first. Tom Kuffel Whitefish, MT Building Original FireStar ________________________________ Message 8 _____________________________________ Time: 02:27:18 PM PST US From: HShack@aol.com Subject: Re: Kolb-List: Vortex Generators update - success! --> Kolb-List message posted by: HShack@aol.com In a message dated 10/21/03 7:29:08 PM Eastern Daylight Time, rwpike@charter.net writes: > Vince Nicely has persuaded me to gap seal the horizontal stab to the > elevators, and I had planned to put some VG's in front of the stab bottom > trailing edge, as the MKIII needs more elevator authority, so tell me more > about how they affect the rudder? (Once you've already got 50 or 60 of the > stupid looking things making your airplane look like a porcupine, what's a > few more?) > > On my Firestar II, I just noticed a good bit more rudder authority. Before, in a slip I could turn her sideways maybe 25 degrees [WAG]; now, it's more like 35 degrees. I put them on my horizontal stab [like you said], but it's difficult to judge effectiveness as I already had plenty. When I saw the significant drop in stall speed [5 mph] after installing 7 on each main rib, I, too figured more is better. I installed one on each false rib, and indeed the stall dropped another 2 mph, but now the stall was violent & would have been dangerous at low altitudes. I took 'em off the false ribs. I also put three on each side of my fuselage, just in front of the widest part. Don't know if they help or not, but my top speed is a little higher & fuel mileage is significantly better than several other local Firestars. Of course, it could be the "C" box w/ 3.47:1 ratio & Warp Drive 68" dia. taper tip prop..................... Howard Shackleford FS II SC ________________________________ Message 9 _____________________________________ Time: 03:31:43 PM PST US From: Subject: Re: Kolb-List: 2SI gearbox service --> Kolb-List message posted by: Tom wrote > Denny, > > It's probably coming from that vent....plug it with some RTV. Otherwise it > will always leak a little gear lube. Not much, but a little looks like a > lot when the air is smearing it around. > > Tom Olenik > Olenik Aviation > http://www.buyitsellitfixit.com Tom, I already plugged the vent per Rogers advice, the oil I was loosing was blowing little oil bubbles around the aluminum seal ring in front of the prop shaft. The pressure buildup from heat in the gearbox was bubbling out the seam in one little spot. I can't pressure test the beast before installation because I still have not found a male 1/16 NPT to hose adapter. Thanks for the input though. Sincerely, Dennis Rowe ________________________________ Message 10 ____________________________________ Time: 04:17:02 PM PST US From: John Hauck Subject: Kolb-List: 912S Hi Torque Starter and Slip Clutch --> Kolb-List message posted by: John Hauck Hi All: Despite the southern part of Alabama and Mississippi covered up in a thick blanket of fog, Miss P'fer and I had a great flight down to South Mississippi Light Aircraft, Lucedale, MS, and back today. By the time I got in the local area of Lucedale the fog had started lifting and we breezed right in. Didn't take long to do the starter and slip clutch install. Test start was a pleasant surprise. The new starter kicks the engine over much quicker. Touch the start switch and the 912S is idling with no low speed vibration. The violent start ups are history. Logged 5.2 hours, 2.5 down and 2.5 back. Flew 400 sm on the nose. Averaged 80 mph for the entire flight. About 5 mph quicker than my standard of 75 mph I use for flight planning. Burned 25 gal 93 octane MOGAS. Figures out to 16 mpg. I had to pickup 5 gal of 100LL in Monroeville, AL, to make sure I had my normal reserve when I landed at Gantt International Airport. Burned 5 gph. I turned the 912S 5,200 rpm for the majority of the flight. Now that I have these updates done I am anxious to get the new 72" Warp Drive three-blade fast taper prop installed and see how it does. Ready to load up and head to Alaska. BTW: Ronnie Smith has indicated he wants to put his name in the pot to go with John Williamson, Tom and Betty Kuffel, and me, next summer. He is repairing a 912 powered Kit Fox that he hopes to make the flight in. Anyone else that is interested in going with us, departing on or about 1 July 2004, put your name in the hat and start getting ready to fly and have an adventure of a lifetime. Take care, john h DO NOT ARCHIVE ________________________________ Message 11 ____________________________________ Time: 04:26:30 PM PST US From: "Paul Petty" Subject: Kolb-List: Medical --> Kolb-List message posted by: "Paul Petty" Kolbers, Today was a great day! The postman delivered my long awaited for medical certificate! Talked to my CFI and this weekend is not looking good weather wise but next week is looking better for my first solo! Off to the shop to finish my hinges on the horz stabs. do not archive pp ________________________________ Message 12 ____________________________________ Time: 05:35:09 PM PST US Subject: Kolb-List: 912S starter and slipper clutch upgrade From: Erich_Weaver@URSCorp.com 10/24/2003 08":34:39.PM@matronics.com, MIME-CD complete at 10/24/2003 08:34:39.PM@matronics.com, Serialize by Router on SMTP102/URSCorp(Release 5.0.11 |July 24, 2002) at 10/24/2003 08:34:47.PM@matronics.com PRIORITY_NO_NAME --> Kolb-List message posted by: Erich_Weaver@URSCorp.com I was also interested in the new starter and clutch for the 912S, but wasnt sure I really needed it. Phil Lockwood of Lockwood aviation was at Copperstate and I asked him directly. His answer: "if you are not having any difficulty on startup, you do not need the upgrade." I dont see how the starter and clutch will help with vibration during flight, but I await John Hauck's report. Phil did recommend that I get the gear box inspected after 300 hrs, but I believe that was regardless of whether you have the new starter and clutch. One last note: for anyone considering the change that is not based near a Rotax service station, the gearbox can be relatively easily removed for shipping to Lockwood or whoever for installation of the slipper clutch. Installation of the new starter is relatively straight forward and can be done by the end user. Check with Lockwood or your personal favorite for the specific how-to directions. regards, Erich Weaver ________________________________ Message 13 ____________________________________ Time: 07:15:50 PM PST US From: "Don Gherardini" Subject: Re: Kolb-List: 2SI gearbox service --> Kolb-List message posted by: "Don Gherardini" Denny.....Shoulda used HondaBond..!!!! hehe Don Gherardini Sales / Engineering dept. American Honda Engines Power Equipment Company 800-626-7326