Think how fast it would be without the floats

[supercub]

http://www.youtube.com/watch?v=gLRLhZJsCh4

441+mph

[Box A35]

Re: Think how fast it would be without the floats

Interesting how the front propeller (engine) starts independant of the rear propeller (engine).

[W J Pearce]

Re: Think how fast it would be without the floats

Interesting how the front propeller (engine) starts independant of the rear propeller (engine).

This comes up every few years....

The MC72 was powered by a FIAT AS.6 V24 which, oversimplified, was two AS.5 V12 engines back to back. The engines could be operated independently of each other even though the rear engine drove a supercharger that fed both engines.

The gear reduction for the props was taken off the the back of the engines; so it occurred between the two V-12 engine sections. The rear engine drove a shaft that was inside of the front engine's shaft. Both shafts traveled through the Vee of the front engine and to the nose of the aircraft. The front engine drove the rear prop, the rear engine the front prop.

The propeller pitch was ground adjustable. The front and rear propellers were adjusted to different pitches to compensate for the supercharger drain on the second engine (front prop), as well as efficiency differences between the first and second set of blades.

Image (if it is there) is from Italian Wikipedia, and shows the gear reduction and shafts of the AS.6:

[flyingjibus]

Re: Think how fast it would be without the floats

one of my favorite planes.

[wyhdah]

Re: Think how fast it would be without the floats

Mine too jibus. I have thought about the subject some in the past supercub and I think it would be hard to go much faster because some drag inducing cooling apparatus, to replace the job the floats are doing to cool the engine, would be needed.

Basically the floats are why the plane is so sleek.

[flyingjibus]

Re: Think how fast it would be without the floats

Basically the floats are why the plane is so sleek.

Same with my Slow Stick

[Arctic Cat]

Re: Think how fast it would be without the floats

This comes up every few years....

The MC72 was powered by a FIAT AS.6 V24 which, oversimplified, was two AS.5 V12 engines back to back. The engines could be operated independently of each other even though the rear engine drove a supercharger that fed both engines.

The gear reduction for the props was taken off the the back of the engines; so it occurred between the two V-12 engine sections. The rear engine drove a shaft that was inside of the front engine's shaft. Both shafts traveled through the Vee of the front engine and to the nose of the aircraft. The front engine drove the rear prop, the rear engine the front prop.

The propeller pitch was ground adjustable. The front and rear propellers were adjusted to different pitches to compensate for the supercharger drain on the second engine (front prop), as well as efficiency differences between the first and second set of blades.

Image (if it is there) is from Italian Wikipedia, and shows the gear reduction and shafts of the AS.6:

Thanks for sharing that. Thats a pretty simple setup, I imagined a much more complex drive system to have both props independent.

[C_roundy]

Re: Think how fast it would be without the floats

This comes up every few years....

I also gotta thank you W. J. Pearce, I have read ALOT of books that touched on the airplane. But now, finally, I understand it's drive-train.

[W J Pearce]

Re: Think how fast it would be without the floats

Glad I could shed some light on the AS.6. Like with everything else, there is a lot more to it, but it is a fairly simple concept. I'm just glad the net is moving away from the "rear engine drove a shaft through the hollow crankshaft of the front engine" description that has been around.

And I should have used better words than "operated independently" for the engine sections. I meant that engines were not coupled together. They shared a crankcase and an induction manifold, and there was only one throttle. Everything else was separate (ignition, coolant, fuel). As the video shows, one engine section could be run without running the other engine section, but the AS.6 was not intended to run that way.