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Touring Motor Gliders Association (TMGA)

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  1. Last week
  2. L. Adams

  3. brasov


  4. Eric Greenwell

    Phoenix 912 engine loses 500 rpm during climb

    The problem was found and corrected last week. It was just luck that I got the information needed to solve the problem: during a ground test at full throttle, a video recording of the exhaust pipe caught two puffs of black smoke about 20 seconds after the engine RPM dropped by 500 and a strong vibration started. The video recording was intended to measure the effect of the exhaust diverter on the exhaust pipe. After seeing the video of the puff of smoke, my mechanic (Jim) consulted the Lockwood people, and all agreed a sticking exhaust valve was the most likely cause of the RPM loss and vibration. Jim did the valves on all the heads, and the engine runs smoother and about 300 rpm faster at full throttle on the ground. The #1 cylinder exhaust valve was the culprit, with thick black, almost "gooey' deposit about 1/2" long on the valve stem from the valve head up. The valve was tight in the guide, and the guide was difficult to ream out, but both valve and guide were in good condition, once the deposit was removed. The other exhaust valves were in good condition, but perhaps with more deposit on them than normal. I did not get a picture of the #1 valve, but the attached image shows the worst of the other valves. On #1 the entire deposit was as black and thicker the black ring on the pictured valve. Jim was not sure what caused the heavy deposit on the #1 exhaust valve, but offered several suggestions: The extended idling I do while soaring (gliding) might not be keeping the valve hot enough to prevent deposits from forming. I estimate I've idled in flight about 200 hours out of the total 600 hours of engine time. Possibly, lead from using 100LL might cause a sticking valve, but most of my flying is with E0/91 AKI fuel, so that isn't likely. He suggested I test the E0 mogas I've been using; I did so, and it tested good (no alcohol) so it's probably not the fuel The only time he's seen such a thick, almost gooey deposit, was in plane with tanks sealed with the wrong product for fuel with ethanol. Not likely my problem, as none of the other 50+ planes have had any problems. Of course, I want to avoid this problem in the future. One way is to do my soaring with the engine off, propeller feathered, as was intended by the designer! There can be difficulties with that approach, but I think I can cut the engine idling time in half with only a bit more effort while soaring. Another possibility is some additive that reduces the build-up of carbon on exhaust valves, but I don't know what it is. Any ideas? Thanks to those that responded with ideas about the problem. Even though none of them solved the problem, they did get me and others think more carefully about the situation.
  5. Earlier
  7. brasov

    Brasov IS28M2.jpg

  8. Jim Lee

    Dynon autopilot service bulletin

    All USA Phoenix with Dynon autopilots have the SV 32 autopilot servos which are not affected by this bulletin.
  9. Eric Greenwell

    Dynon autopilot service bulletin

    My servos are the standard rotary style, not the linear actuator style, so I'm not affected. I doubt any Phoenix has used the linear style.
  10. Has anyone checked out the issue involved in the latest SB from Dynon regarding the autopilot? https://dynonavionics.com/bulletins/support_bulletin_080219.php TECHNICAL SERVICE BULLETIN: SV42T SERVO PULLEY Original Bulletin: August 2, 2019 PLEASE READ THIS BULLETIN IN ITS ENTIRETY BEFORE CONTACTING DYNON AVIONICS Description Dynon Avionics has received reports of cracked pulleys in the SV42T linear actuator servo. This can cause poor autopilot performance and presents a risk of interfering with the flight controls. Applicability and Affected Equipment This bulletin affects the pulley on the Dynon linear actuator, which may be found on: Some Dynon Avionics SV42T Autopilot Servos (P/N 101008-003 / 101058-003) Some SV32 and SV42 servos retrofitted with the Dynon linear actuator Fig 1: Dynon SV42T servo with linear actuator Unaffected Equipment The following equipment is NOT affected by this service bulletin SV32, SV32L, SV32C SV42, SV42L, SV42EL, SV42C SV52, SV52L, SV52C Additionally, Dynon Certified installations are unaffected by this service bulletin. Interim Operating Recommendations Due to the nature of the issue, we recommend complying with this service bulletin before further flight. However, it is up to the owner/operator to determine the airworthiness of the aircraft for flight. Solution Perform the following: If you received your SV42T or linear actuator assembly before 12/13/2011, it is unaffected and can remain in service. If you received your servo, or linear actuator assembly after this date, inspect it as follows. Inspect the pulley for a crack from the center of the pulley through shear screw bore. (Fig 2) It may be necessary to engage the autopilot on the ground and apply force to the control surface in order to load the pulley to make the crack visible. If a crack is found, remove the servo from service and return to Dynon for repair/replacement. If no crack is found, inspect the pulley to determine whether it is affected: Unaffected pulleys have a crosshatch weave pattern in their material weave and a plastic-like smooth texture. Inspect the pulley for texture and visually with a magnifier. If a crosshatch weave pattern is present (Fig 3), the pulley may remain in service. Affected pulleys have a unidirectional wood-like “grain”, and a finish that appears dull looks similar to wood. If your pulley matches this description, remove from service and contact Dynon for repair/replacement. To remove the servo from service, you may opt to remove the entire servo assembly, or if more convenient you may remove the entire linear actuator sub-assembly by following the “Servo Arm / Capstan Removal and Replacement Instructions” on the Dynon Documentation Website. Whether you remove the servo or linear actuator, ensure that any remaining linkages are secured and do not interfere with flight controls. If you choose to remove only the linear actuator, disable the servo circuit electrically to prevent misleading autopilot behavior. This can be accomplished by disconnecting the wiring to the servo and/or removing its fuse or turning off its circuit breaker. Fig 2: Affected pulley design with crack Fig 3: Serviceable pulley design Time in Effect This technical service bulletin is in effect indefinitely or until superseded by a future bulletin. Notice to Special Light Sport Aircraft (S-LSA), Dynon Certified, and other Non-experimental Customers You are solely responsible for ensuring that your aircraft is airworthy. In the case of S-LSA aircraft, owners may need special authorization to service the aircraft if such operations are not permitted in the maintenance manual. Please refer to your aircraft maintenance manual or contact your aircraft manufacturer concerning this service bulletin. This service bulletin does not affect installations of SkyView HDX that are approved under Dynon’s STC program. Additional Questions? Contact Dynon Avionics Technical Support via phone (425-402-0433) or email support@dynonavionics.com
  11. Eric Greenwell

    Exhaust diverter to keep fuselage bottom cleaner?

    110 hours on the diverter - belly still clean, no apparent problems. I spent about an hour searching for remarks on using diverters, tips, and extensions. I didn't find any remarks about tips, etc, causing problems. I also queried the Rotax owners group (https://www.rotax-owner.com/en/912-914-technical-questions/7470-using-an-exhaust-pipe-with-a-curved-tip") and got 178 views, but no replies. There are many cars, trucks, and airplanes using diverters like the one I use (and lots of them for sale), but the problems appear to be rare. That doesn't mean my situation isn't a problem, of course. I did find a few articles describing how mufflers reduce the amplitude of the exhaust gas pulsations, and perhaps the Phoenix muffler is doing enough of that to avoid problems. Another mitigating factor is about half of my hours are at idle, because I leave the engine running while soaring. I wish I had a vibration sensor I could put on the exhaust pipe to measure the amplitude; in the meantime, I'll record video of the tailpipe from idle to full throttle during a ground run.
  12. Phoenix motor glider based in Columbia SC at KCUB. Selling 50% partnership. Always hangered, well maintained. 700 hours and presently flying less than 100 hrs/year. Price negotiable and existing partner must approve. Turn key with hangar, insurance, local maintenance all set. Local instructors for glider endorsement and self launch available. e mail drkingery@gmail.com
  13. Cupertino Aviation Clubs

  14. brasov

    San juan river.jpg

  15. brasov


  16. Jamey Jacobs

    TMGA active?

    It's a pleasure to report that my new (to me) Phoenix has been a real pleasure to fly! So far, I have done some local touring and thermal soaring - both wonderful and successful. My Phoenix (s/n 18) belonged to Hugh Bickle who is an exceptional pilot who grew up around soaring (Paul Bickle, his dad, held many soaring records and ran the Edwards AFB flight testing for decades of spectacular milestones in aviation). Hugh took excellent care of the Phoenix along with his P-51 and other great aircraft. Jim Lee (US National Open Class soaring champion - 2019) has provided excellent instruction and support - Thanks Jim! The handling of my Phoenix is as-advertised - well harmonized, responsive and very fun! Landings do require a good set-up and attention especially in gusty conditions - but it's feeling pretty natural as long as I don't try to push it in gusty crosswinds! Here are a few pictures from a recent flight touring Yosemite National Park and a soaring flight with thermals to over 10,300'.
  17. brasov


  18. Jim Lee

    Parachute cover attachment

    Tesa transfer tape from Wings and Wheels. https://wingsandwheels.com/tapes-seals/tesa-transfer-tape.html But the most important tape is the top seal. It must be fresh tape, not old. Use Bowlus maxi seal tape also from Wings and Wheels. Retape at least once a year when you do the annual inspection when the cover is removed to inspect the parachute.
  19. Lost our parachute cover in flight this weekend. I have tried several times to retape the double-sided tape underneath as well as the white sealing tape on top. Alas, the adhesives are not sufficient under the hot summer sun and the hangar temperatures up to 115 degrees. Anyone know of better tape that is less susceptible to heat? David Sheridan U15 / #14
  20. Jamey Jacobs

    Canopy seal

    Doug, have you resolved this yet? If not, I used the Tesa Transfer double-sided tape from wings and wheels. It's working so far (about 2 weeks). I also did some research on glues which bond to silicon, but will try them if the tape solution doesn't work.
  21. brasov

    Hoffmann Propeller

    I sent 1st run Hoffman prop to Aviation Propeller in Fl. The overhaul quote was $8,200.00
  22. Kmotexas

    Carbon fiber panel

    Electro air EA-1300 / I modeled the instruments in SW and inserted a picture of the instrument .
  23. Norm

    Carbon fiber panel

    Where did you find the models for the gauges?
  24. brasov


  25. Andrew

    Carbon fiber panel

    Thanks in the process of generating the engineering to replace with a 100hp Rotax so will need to update the panel shortly. where did you get that nice ignition switch panel from
  26. Kmotexas

    Carbon fiber panel

    The File is still in REV status. When done I will post the design. just found out you own a 109 too......... material is aviation approved carbon fiber. About $900 included cutting ( without markings ) markings silkscreen about $300 ipad support ( 3D printed $80 each ) All engine instruments UMA ( set about $3500) redesign to your spec $ 50 per instrument . SolidWorks2018 is required to redesign. Klaus klaus
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