Pump driven prop????

[Montblack]

On the stern of some paddle-wheelers are the paddles. One I've been on had
its paddle-wheels run by pumps. Pump line ran out of the engine room and
terminated in a smallish box next to/attached to the wheel's axle.

Would that idea work for aircraft. Pump driven prop?

One advantage would be aerodynamic streamlining of the cowl. The nose of the
plane could be almost bullet shaped ...engine might be mid plane - anywhere
really. Engine's prop shaft no longer an issue.


Montblack

[[email protected]]

Mountblack said:-

> Would that idea work for aircraft. Pump driven prop?

Yes, however:-

Hydrostatic drives shuch as this are fairly common in
heavy construction equipment and the like however
there is a problem.

There is too much loss even for ordinary car use and the
fuel consumption is unacceptably poor.

I would guess that this would be an even more serious
issue in aircraft.

[Morgans]

> wrote

> Yes, however:-
>
> Hydrostatic drives shuch as this are fairly common in
> heavy construction equipment and the like however
> there is a problem.
>
> There is too much loss even for ordinary car use and the
> fuel consumption is unacceptably poor.
>
> I would guess that this would be an even more serious
> issue in aircraft.

Indeed, there would be, and one large problem is called weight. It wo8uld
be extremely heavy.

Also, those loss issues bring up another problem. When you have loss, what
happens to that energy? Energy can not be created or destroyed, and that
energy put into loss shows up as heat. Boatloads of heat that must be
dissipated, and that will take a lot of radiator, and air to go through it.
That will cause wind resistance, which will slow the plane, so much as to
make a biplane seem speedy.
--
Jim in NC

[Tater Schuld]

> wrote in message
oups.com...
> Mountblack said:-
>
>> Would that idea work for aircraft. Pump driven prop?
>
> Yes, however:-
>
> Hydrostatic drives shuch as this are fairly common in
> heavy construction equipment and the like however
> there is a problem.
>
> There is too much loss even for ordinary car use and the
> fuel consumption is unacceptably poor.
>
> I would guess that this would be an even more serious
> issue in aircraft.

not to mention heat issues due to friction and the fact that it adds another
link in the chain to fail.

oh, and weight. those hydraulics aint light

[[email protected]]

Montblack wrote:
> On the stern of some paddle-wheelers are the paddles. One I've been on had
> its paddle-wheels run by pumps. Pump line ran out of the engine room and
> terminated in a smallish box next to/attached to the wheel's axle.

My guess is that this offers certain advantages such as preventing
the paddles from back-driving the drive train when the engine is
throttled down and also making it possible to use valves to reverse
the paddles direction.

Such a system will also be more efficient for low speeds than for
high speeds.

>
> Would that idea work for aircraft. Pump driven prop?
>
> One advantage would be aerodynamic streamlining of the cowl. The nose of the
> plane could be almost bullet shaped ...engine might be mid plane - anywhere
> really. Engine's prop shaft no longer an issue.
>

A drive shaft is a far more efficient means to transfer mechanical
energy from the engine to the prop.

Consider the P-39 Airacobra. Engine was behind the pilot, the
prop out in front.

--

FF

[TerryJ]

Too heavy to fly but....
here is a hydrostatic diesel hog though.
http://www.findarticles.com/p/articles/mi_m0FZX/is_12_70/ai_n8681022
"Montblack" > wrote in message
...
> On the stern of some paddle-wheelers are the paddles. One I've been on had
> its paddle-wheels run by pumps. Pump line ran out of the engine room and
> terminated in a smallish box next to/attached to the wheel's axle.
>
> Would that idea work for aircraft. Pump driven prop?
>
> One advantage would be aerodynamic streamlining of the cowl. The nose of
> the plane could be almost bullet shaped ...engine might be mid plane -
> anywhere really. Engine's prop shaft no longer an issue.
>
>
> Montblack
>