flyrotary@lancaironline.net Mailing List Archive

Let me first clarify, my reference was for a Turboprop or turboshaft. Tracy is correct that on TurboJets and TurboFans the 75% Air is routed around combustion chamber, cools it and then mixes with the hot gases to provide thrust. In a turboprop/shaft engine almost all of the heat energy is used up by the turbines that it passes through. In fact on the C-20J After a two hour flight you could put the exhaust covers on instantly because the exhaust tubes were not hot. A traditional auto turbo is a turbine wheel and a compressor. Take two of them and you almost have all the parts you need to build a cheap Turboprop putting out a few hp. Bob I think what you are saying is that it would be improbable to use the air to cool the oil or water temperatures and so I would have to route the air directly over the combustion chamber, just like in the turbine. Basically drilling additional holes in the rotor housings. So I guess my thought is to try and harness that exhaust energy we are producing to provide for something. Maybe have the turbine wheel turn a generator/alternator. Mark Glasair SII - 30% complete 13b MSP - 5% complete On Jan 27, 2012, at 9:26 AM, Rogers, Bob J. wrote: If you add another turbo to capture the remaining exhaust gas, the compressor portion will generate compressed air, which can be directed to flow over an oil cooler or a radiator, but the air will be much hotter than the outside air available for cooling. When the air is compressed, it is heated by as much as 100 degrees. The temperature rise is a function of the amount of compression. That is why you need an intercooler before such air is routed to an engine intake for combustion. I doubt that the air from a compressor stage of the turbo would be cool enough to help reduce the water or oil temperature very much (if at all) and the volume of air would not be significant compared to the volume of air available in the free stream of outside air. Plus you have the added weight of the turbo to deal with. In short, it would not work. Bob Rogers Mustang II, powered by Rotary 13B Turbo -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ernest Christley Sent: Friday, January 27, 2012 11:09 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: engine exhaust Mark McClure wrote: The 13b MSP is putting out exhaust temps of 1600F. So using the same principles in reverse, the remaining energy powers a compressor (turbo) and that air is then used to assist in the cooling. So the question is: What have I oversimplified? Mark There is so much about the rotary that is completely unexplored. An option that I'm investigating with my installation is to have a blower attached to the shaft between the engine and PSRU. The goals are: - to make more of the propeller efficient by removing the high pressure area from between it and the cowling - remove that high pressure area at the nose and - use it to increase manifold pressure - increase the manifold pressure - in a extremely simple and lightweight method. I've seen the videos of people making jets out of turbos. I've not run a single number, but it seems like it would be possible to duct the output of a really thick radiator to the input of a large turbo. The pressurized air would cool the turbo and get heated in return, then combined with the exhaust to produce thrust. I do seem to remember someone on this list doing an analysis and coming to the conclusion that a "rotary jet" was not viable, but if you're getting a list of drag reducing benefits, dealing with the exhaust (one of the worst pain points we've had to deal with), AND getting some measurable thrust ... you'll get listed as a hairy chested hero. -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html