The prototype KR2s Joe is referring to was Roy Marsh's plane, N133RM. ?Last I heard, Roy was living in California, although the plane has changed hands a couple of times since then. ?Last I knew it was also in California.
Seems to me that Dan Diehl ran a turbo VW in N4DD for a while as well, so may have some useful information. Sounds like you are taking a sound approach with this. ?Congratulations on the fine work. -Jeff Scott Los Alamos, NM > ----- Original Message ----- > From: Jeff Lange > Sent: 03/25/13 08:51 AM > To: KRnet > Subject: Re: KR> Turbo VW Tests > > Jeff, > > I do have quite a few concerns about a number of things. The crank is a GPAS > forged unit with the Force 1 prop hub. If any crank can handle the loads I > think this is my best bet. My biggest concern is the case itself. I may have > to go with a larger type 4 center bearing or go to something like the > aluminum Scat "killer case". > > Cooling the power will indeed be a challenge. The water injection will help > but only testing will tell. > > Right now I am running it like the Revmaster turbos ran, without a waste > gate. I may have to add one. I have noticed that once the boost is in, it > does not take much more throttle to get more power. I have considered a > throttle stop that is hinged to prevent a serious over boost that is deployed > during takeoff and landing but I'm not sure how that will work out. I have > looked at a few waste gates but none of them are programable. The would just > be set to pop off at whatever pressure its set at preventing over boost. > > The ignition is also set up so that if an over boost happens the ignition > timing drops to 0 but the mag is still firing at 25 degrees BTDC. Again, I am > going to have to see how it works out. Joe at Revmaster said that the > prototype KR2S was turbocharged and ran up to 6psi with the timing set at 25 > degrees. If anyone knows anything about this please let me know! > > I did drop the compression from a little over 9:1 to 8:1 by installing larger > shims under the cylinders. 8:1 is what Joe recommended. Its still higher than > the 2.5l turbo in my Subaru car, but that is running about 14psi of boost > (60"). If I recall, its CR is 7.5:1. > > There will be many test flights and inspections along the way. Initially, > I'll normalize and then slowly work up to more power. The engine will have to > be torn down next winter to see what the results are. The engine is being > torn down next month to see what it looks like inside. Its got about 50 hours > of full throttle operation at over 4000rpm's on it now and I want to see how > it's held up to that. > > I'm in no big rush since I have the KR to fly. If the Sonerai takes all > summer I am just going to race the KR at cruise power. > > Thanks! > > Jeff Lange >
