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Hi Dave; How far downstream of the turbo are you measuring your TOT? I measure mine about 16" downstream and so far in static ground runs I only see about 550C max. But I also measure both rotor exhaust ports and while I see temps of 950C, only 2" further downstream where the two streams enter the turbo I measure the TIT at usually 50C or more lower. So distance certainly does allow the the flame to cool, but I also assumed that the turbo was converting some of the heat energy to mechanical energy along with the mechanical energy it is already harvesting from the exhaust gas flow.
I hope to get better data soon but smokey skies from nearby forest fires have darkened our skies and kept me on the ground. Been doing some hi-speed runs on the inactive runway between water-bombers coming and going from their base which use that runway as a taxiway, while I'm trying to get a handle on this tailwheel thing. I think it will be much easier when I can just fly it off, instead of just the tail.
Dave
That’s great news. TOT is the outlet temperature? If so I would have expected it to be lower. The last coupe of years I have been successful in keeping climb EGT’s under 1600F on most flights. High OAT and quick fuel stops are the exception. But I think the heat soaked engine and super charger is the cause. Performance actually increases after climbing and everything cools off. Typical F/A for initial climb is 11.3 :1 for 1600F EGT’s. I ended up with an O2 bung on each rotor and tuned for a near perfect match between 28-40” MP. Unfortunately the EGT spread varies a lot in other flight conditions. I’m slowly working on a turbo FWF to replace the supercharger. I’ve done most of the work on the header with he exception of wastegate, down pipe and bungs. The turbo is located as faraway from the exhaust ports as I could mount it in hopes of dropping EGT’s a little more.
Link to photos
Bobby
Sent from my iPad Hi Bobby,
Yes, no new torbo failures since I decided to keep TOT (the only place I measure exhaust) less than 890C. Basically, I treat it like an aircraft engine. Rich of peak for climbing and decending (TOT around 810C) then lean at altitude when the MAP is lower (around 870C). Peak TOT is around 915C.
Dave Leonard Dave
How is the turbo holding up? Is keeping EGT’s under 1600F keeping it alive?
Bobby 500 hrs Sent from my iPad Thanks Kelly! Yes, I am still using the flywheel and strongly suggest not using the flex plate. Adaption was easy with a trip to a local machine shop. Details are in the archives. Dave, Not aware of a flexplate/flywheel replacement made specifically for use with Tracy's redrive but Dave Leonard (Turbo/13B-RV6) adapted an aluminum racing manual transmission flywheel to his redrive after his flexplate developed serious cracks while qualifying to race at the Reno National Air-Races several years ago.
Perhaps Dave will jump in here with how he did it.......I know there are a series of E mails in the archives with photos of how he did it....As far as I know he still is flying with this flywheel........FWIW
Kelly Troyer
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