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Engine Questions

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Hey gang,I think this may have been asked before...but here goes:1) What would happen if I took my 231 V-6 out of my Buick (aah, what an engine) and put it in a Cessna? I guess what I'm driving at here is the differences between car and airplane engines. I would think that if an auto engine would have some application in airplanes that General Motors and Ford would be competing for some of the market.2) I don't think this one has been asked before...On my car, the water pump, alternator, compressor, and power steering pump are all mounted on the front of the engine (well, technically it's the left side since it's a FWD car...but I digress), and the output shaft goes into the transmissions, which is on the other (rear/right) side. Where are the accesories mounted on an airplane? I would think that the propeller were attached to the output shaft of the engine...but where does everything else go?Maybe someone knows of a good, detailed picture/cutaway of an engine somewhere on the Internet.Thanks, guys (and gals)!

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Theoretically, you could install a 231 V6 in an airplane, but I don't think it would be worthwhile. Auto engines are generally quite a bit heavier than aero engines, especially when you consider that you would need to install the rad for cooling. I don't believe that the 231 would have enough power (read torque) to keep a Cessna aloft as well as a Lycoming or Continental, since auto engines produce max power at different parameters than aero engines do. Another point to keep in mind, aircraft engines are set at higher power settings than auto engines are normally run at, and left there for a while. The 231 is a great engine, but how long would it last spending most of it's time revving at about 75% of the engine's designed redline? Then there is the money involved getting certification for approval to install on an aircraft. I think that this is the main reason you don't see companies like GM and Ford lining up to get thier engines in aircraft, the cost for certification is HUGE. As a side note, GMs Allison division built turbine engines before they sold the designs to Rolls Royce. Many Bell 206s are running around under GM power.As for where all the accesories are on aero engines, they are at the rear (except for the alternators on some larger engines). The prop is driven off the front of the engine, sometimes through a gearbox to reduce the prop RPM to a lower value than the engine RPM, but the smaller ones are generally direct drive off the crankshaft. On the back of the engine, there is a section called the accesory gearbox. This is where the engine driven fuel pump, hydraulic pump (if applicable, magnetos, oil pump, starter, tach generator, vacuum pump, and everything else applicable is located. The exception is on some larger engines, where the alternator is gear driven rather than belt driven. belt drives are normally at the rear, gear drives are generally at the front. The accesory gearbox is just that, a gearbox driven off of the rear of the crankshaft, with several mounting pads on the rear face for mounting accessories. Hope this answers your questions!

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Auto engines have been used for some home-built aircraft and are not uncommon. As previously stated, they're designed to produce about 20% power around 80% of the time, where aircraft engines are designed to produce about 75% power at cruise. But conversions are done all the time.Auto engine manufacturers are not anxious to go through the expensive process for FAA engine certification, for airframe manufacturers that are slow to try anything new, and because of the liability exposure. Couple that with the relatively few units they would sell and you can see it's not a very lucrative market.

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