Hank Posted March 27, 2017 Report Share Posted March 27, 2017 3 hours ago, Alain B said: A car engine running at high rpm constantly will not make 500 hours without a breakage of some sort . Look at a Nascar engine , they are extensively modified , in many cases cost more then an aircraft engine ( due to the expensive parts and modifications inside ) , have special oiling system , are maintained by top mechanics , and in some case cannot even go 500 miles without blowing up , much less 500 hours . NASCAR runs a lot more than 5000 RPM--they're up in the 7500-8500 range. Keeping it to about twice normal auto use should help with life, dontcha think? Quote Link to comment Share on other sites More sharing options...
par Posted March 27, 2017 Author Report Share Posted March 27, 2017 1 hour ago, Hank said: NASCAR runs a lot more than 5000 RPM--they're up in the 7500-8500 range. Keeping it to about twice normal auto use should help with life, dontcha think? Some light reading on this subject also indicates that the LS3 is limited to 350ish HP for aircraft use. I believe it is rated for over 450 for auto use. I don't think these engines will have any trouble making it to 500 hours. The biggest downfall of these auto conversions seems to be the reduction unit. Without some serious R&D, it's difficult to make a reliable product for this task. I certainly think something could be developed. Let ok at turbo prop gear boxes that can handle and reduce much higher levels of torque and HP. Quote Link to comment Share on other sites More sharing options...
AH-1 Cobra Pilot Posted March 28, 2017 Report Share Posted March 28, 2017 9 hours ago, par said: What do you think about titanium gears? Is there a reason why this doesn't already exist? You need a hard steel for gears. The tensile strength and the wear-resistance is several times that of titanium. (Not strength per weight, of course. That is what makes titanium special.) Quote Link to comment Share on other sites More sharing options...
Alain B Posted March 28, 2017 Report Share Posted March 28, 2017 2 hours ago, Hank said: NASCAR runs a lot more than 5000 RPM--they're up in the 7500-8500 range. Keeping it to about twice normal auto use should help with life, dontcha think? True , but Nascar engine have micro-polished and extremely well balanced 180 degrees crankshaft , Carillo titanium connecting rods , up to .1 gram balanced piston , extra light and expensive valve train , and all kind of exotic stuffs build-in . Sure they will most likely run 500 hres at 4000 or 4500 rpm . In this rpm range they will not make more power then a regular out of the box aircraft engine and they cost as much if not more then a brand new Continental or Lycoming, who will probably run somewhere near 2000 hours . .Plus they need a radiator , have a complex and very expensive dry sump oiling system , they are not lighter. I dont see any advantage about them . Quote Link to comment Share on other sites More sharing options...
aviatoreb Posted March 28, 2017 Report Share Posted March 28, 2017 People like the car engine that comes from the corvair, since it already runs at correct aviation rpms. Quote Link to comment Share on other sites More sharing options...
Yooper Rocketman Posted March 28, 2017 Report Share Posted March 28, 2017 10 hours ago, par said: At this point, it's just a dream. I haven't through about exactly which model I will go with but I know it will be a lancair. I also agree with you re the engine choice. I have read a lot of negative stuff about car to plane transitions and I def don't want to pick from the two choices you listed. I'm hopeful that we will have a good turbine solution by that point as that would make for the ultimate fast plane. There are two Lancair 360 kits listed for rediculously low prices just recently. Add a decent used IO360 and some sweat and you would have a phenomenally efficient traveling machine for pretty cheap. And you could perform your own maintenance and annuals as well. https://lancairtalk.net/viewtopic.php?f=10&t=3115 Tom Quote Link to comment Share on other sites More sharing options...
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