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Don,
I'm just a bit ahead of where you want to go, but way behind on the rest of the plane. I'm wingless in the garage at home, test running in the yard with the tail tied to a cedar tree.
I'm building an RV-8 with a turbo 13b. I welded up my own exhaust manifold mounting a Turbonetics 60-1 using an 'on center' TO-4 turbine housing. The compresor faces forward and a cone shaped K&N filter is direct mounted to the compressor housing. The exhaust is an S shaped 2.25" pipe that crosses in front of the firewall and exits out the center of the cooling air exit (cowl flap area) parrallel to the sheet metal ramp. The pipe is supported with a clevis to the engine mount plate (between the block and oil pan) so it all moves in harmony with the engine/turbo, yet can grow a bit from heat. So far the turbo muffles the engine fairly well.....but I have not gone to War Emergency Power.....yet.
I 'borrowed' David Leonards radiator advice, and mounted it under the chin, making a fairly generous scoop, which I tested today.
the oil cooler is mounted on the right side and uses the entire airflow from the right cowl cheek opening. Separate air paths for radiator and oil cooler helped solve my previous cooling failure.
I ground ran for 20 minutes today, building up RPM as it warmed up, and the temps are stable. I chickened out and held at 3850 RPM for the last 5 minutes, the highest I've gone yet. water temp stable @ 154F, Oil stable at 172F. Tracy's engine monitor gives direct HP readout based on fuel flow, so it varies as you adjust the mixture, but I ran up to about 50HP with firm temperature control. This was very exciting for me becuase it's enough power that the fuselage is starting to buck and shake like there might be some power there, and promises of more.
I have not done anything with the left cowl cheek opening yet. Air entering here goes right to the tubo air filter, and washes over the fuel injectors, turbo assembly, and spills out the bottom with the heated radiator air.
To keep from choking the heated radiator air, I'm thinking of making a duct to carry the left cheek air out the left side of the cowl, where I could mount an intercooler. I've trial fitted a stock Mazda intercooler here, I would need to remake the air tubes into/out of it. The important part of this is cooling the fuel system and isolating the turbo heat from anything it could damage. Dave warned me of this early on, and I have not forgotten it.
Constructive comments are always welcome!
Scott
PS, I'm working very hard to keep this simple and light. Weight adds up fast!
-----Original Message-----
From: David Leonard <wdleonard@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sun, Feb 7, 2010 3:24 pm
Subject: [FlyRotary] Re: N.A. Renesis to turbo
Hi Don,
Kinda busy right now but will have some time tuesday night. You did a great job on your plane and should be able to pull off an excellent turbo conversion.
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
On Sat, Feb 6, 2010 at 6:21 PM, Don Wallker <drwalker@gbis.com> wrote:
Dear list, Turbo flyers and especially David Leonard,
I've 16 flying hours on my RV-8 with a Renesis and all of Tracy's stuff and a Catto 76/88. The airplane flys great, just like an RV, no gliding time, and about 36 hours on the ground. SPECS
Full throttle 8,000' 174 mph indicated, 2450 on the prop, water 185, oil 205,
Climb out 110 mph, rate of climb, 1250'/min. Field elevation 5046.
These are not bad numbers, but I would like better. I've been influenced by some of the the local jet jocks who say that there is no such thing as too much horsepower and they are right! N113BR seems to be performing about like a 160-170 HP RV. So I am investigating turboing it! The idea is to have a little better than sea level performance on take off (designed for 210HP N.A.) and turbo normalizing at cruise. Up to 12000' would be nice.
During the air races this year, Dave Leonard showed up and I was very impressed by his airplane. He was able to turbo and inter cool it and have it all inside an RV cowl, so I'll likely base my installation on his. Plus, he has been through the learning curve of 3 or so turbos so he knows what to do, what not to do and what would be better if he were to do it all over again.
I've spent the afternoon looking through the archives, reading as much as I can find about turbos, and downloading all the photos I can. Here is what I am tentatively planning on doing.
Get one of Techwelding's Renesis exhaust flanges made from 304 SS and have my local waterjet guy copy it and make one out of 321SS. I'll weld 321 SS and manifold it together and run it into the bottom of the turbo that will sit right in front of the exhaust. The turbo will have additional support. Run the turbo outlet air from it through a stock RX-7 inter cooler sitting in front of the left cheek opening and then out to the right side of the engine, probably routing it under the PSRU and then up to a throttle body and manifold. Then four al tubes over the top of the engine into a cut down and welded up stock RX-8 intake manifold. The exhaust out of the turbo will run down and out in the usual center of the back of the cowl opening. I am thinking of trying one of Burns Stainless all SS mufflers. It is basically a glass pack, but instead of glass, they are using stainless steel wool and they say it is holding up for the rotary racers. They make it any length you want and is about 4 lbs with their SS vs 9 lbs with the hushpower 2 I'm using now. The combustion air intake to the turbo will be on the aft left side of the cowl via an NACA duct opening as Dave's is.
The oil cooler will have to be moved to under the engine. I will build up a fiberglass scoop, probably based on Van's scoop and modify it to have a bigger opening and be farther forward, closer to the prop. I will probably have the oil cooler made a little larger (Techwelding) than the one I have now.
That's the basic idea at this point. I'll finalize my plan, prebuild as much as possible before tearing the airplane apart and try for as little down time as possible. I'm looking for the list's critique here, plus questions that I will have missed. The following are a list of questions that I have.
1. Which turbo should I use, which orientation and who should I use to do the work, plus what is the approximate price? TO4 hybrid? Dave and Steve Brooks mention BNR turbo as a modifier. Who manufactures the turbo?
2. What is the ideal situation with a waste gate? Full open or not, or, or?
3. I read about a N.O.oil line solenoid to the turbo bearings. I assume that if the Turbo fails, you turn it on to the N.C. position to prevent oil from being pumped down your exhaust? I assume the oil that is used is routed back to the sump.
4. What size exhaust is optimum? It seems Dave is running 2.5 inch.
5. What size throttle body should I use and what would be a good one? One throttle body or two? 4. What size injectors should I use, and where should the secondaries be placed? Dave is using 480cc and staging is at 32 inches. Are you using the same for the primaries and is there an idle problem with the larger injectors?
5. Anyone out there turboing a Renesis? Anyone flying one?
6. My compression is 9.7 to 1. Any problems with this higher compression ratio as long as I use an inter cooler and keep the boost no higher than 35"?
And lot more questions, but that's all I can think of now.
So If any of you can add any thought, let me know.
Don Walker
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