On Nov 3, 9:13*am, Ricky wrote:
A question for the physics-minded among us, or for anyone who just has
the answer.

I have heard the Airacobra was underpowered and that got me to
thinking;
Does having an engine at the middle of the fuselage (in any plane for
that matter, like the XP-58) and connected by a long shaft contribute
to a loss of power delivered to the propeller? In other words; would
there be more power delivered the closer the engine is to the prop?
Does the shaft "eat up" power in any way? I am a mechanic and pilot
and fairly knowlegable about a/c physics & aerodynamics but this has
me stumped.

Thanks in advance for your ponderings and/or solution!

Ricky

Ricky, the question you'd have to ask is, if the energy is put into
the shaft at the engine end, where could it go? One answer is heat,
the the other sound energy, but really most of it is delivered to the
prop. Long shafts do cause vibration problems, but those can be
overcome.

As it happens, there are other reasons for putting engines close to
the front of a single engine airplane. The middle is a good place to
park passengers, you avoid the weight/space issues with the shaft.

My aerodynamic question had always been why there are fewer pusher
props. In a puller some of the wind energy is used up against the
airplane. In fact one of the things that made the Mooney 201 better
than the Executive is the windscreen and cowling were redesigned to
more effectively deflect the wind. In the case of the Mooney, the wind
against the airplane is airspeed plus that contributed by the prop,
and losses go up like something of the square of wind velocity.

This could be a long thread, and some posters may actually contribute
to the discussion.