Turboprop or Turbofan powered experimentals

[steveinindy]

I talked to Epic last year since they are the closest to what I am trying to achieve. The sales guy pretty much told me to bugger off because I wasn't looking to buy one of their kits (as I would kind of expect). Nothing on the market at the moment meets the criteria- more so the safety aspects rather than strict performance- I want so I have to design it myself. This is not to mention that I am enjoyed the academic and practical exercise that is designing an aircraft from the ground up. I will talk to CompAir and see what they suggest. Surprisingly, the Lancair guys at Oshkosh this year were quite willing to discuss the particulars of designing and building a pressurized aircraft with me.

[hogheadv2]

May want to look into this site, they were at Oshkosh in the Exp. area. http://www.diemechturbines.com/

[danielpace]

I'm primarily looking at one of the RR M250-B17Fs at the moment although I might talk to the PWC folks next week at Airventure about what they have to offer. The original plan was to use an aviation diesel but that doesn't seem feasible due to a lack of sufficient horsepower in the currently available models with the exception of one.One of the major issues is that my design is a canard design so it has a pusher arrangement. Once I realized that the diesel option was more or less not viable, the first option I considered was putting a turbofan into the design, but from a fuel consumption standpoint that doesn't seem particularly viable either. My desire not to use a 100LL powered engine for safety reasons (not to mention avoiding having to re-engine once 100LL goes away) limits me to either a diesel or a turboprop then.

Have you looked at the Deltahawk turbo diesel?

[steveinindy]

Have you looked at the Deltahawk turbo diesel?

Yeah, they are non-certified at the moment so they are not viable options. Also, they are not very powerful given their weight and fuel consumption. The only advantage they have is that the initial purchase price is cheaper.

[Mike Switzer]

If I wasn't busy with other things (including structural engineering on a tube frame aircraft) I might try a modern redesign of a Junkers Jumo Diesel. The big problem with diesels (as I learned when I was working for a major diesel engine manufacturer in Illinois) is that in diesels, cast iron is reliable, & heavy. Aluminum is light, but it flexes too much under the combustion pressures & sooner or later you have a problem.

I'd love to put something along the lines of a 6-71 or 8V-71 in an aircraft if they didn't weigh almost as much as a empty 172...

[hogheadv2]

Here is more power pusher running on gas. Read the site, does sound like they may be certified in some planes. http://www.v8aircraft.com/
Mould not be hard to add a preasure equallizing turbo to go for 18-20,000 ft. EFI cures all the mixture and timing issues, back-up crank trigger but 8 seperate coils are a great idea.

[steveinindy]

Thanks for the suggestion but I'm not going to use a converted engine. I just don't like the idea, nor do I want to use anything that runs on gas, especially automotive gas. I'm pretty much settled on a turboprop of some type with the two most likely options being a RR500 or some variant of the PT-6A.

[Mike Switzer]

Unless I can find a light diesel I'm putting a blown small block ford in mine. That is the most reliable engine I have ever worked with. (My buddy is trying to talk me into using a blown Lincoln MK8 engine but I'm resisting...)

[steveinindy]

More power to you (literally and figuratively). I'm not sure I trust the idea of using automotive gas for reliability reasons at altitude and in the event of a crash, I'd prefer to be packing the least flammable fuel possible around. There are those who claim the reliability issues are overstated, the flammability issue is moot (usually prefaced with "Well, you aren't planning on crashing are you?") and that there is no significant difference between an automotive engine and one designed purposefully for an aircraft. However, I'm willing to pay for that piece of paper that says the engine was designed to meet the stated standards for the industry. This is especially a factor since I may eventually (if the design is a success) go for standard category certification of the design.

[Mike Switzer]

If I'm running a gas engine it will be able to run 100LL, lots of places you cant get mogas. Just a matter of fitting aviation plugs to your heads.

Ideally I want to be able to run farm (no tax) diesel and burn jet fuel when travelling but there isn't any engine out there that I think is light enough.

My truck has a 7.3 Powerstroke in it & it is one of the best engines I have ever worked on (I was actually on the design team for the fuel system) but it weighs over 750lb, the power to weight ratio is way out of whack there. Even with 65 psi in the front tires they look like they are low.