Strange propellor setup

[Dick]

Has anyone seen or heard of a propellor with the center hole being maybe a
10" diameter so that the prop could be driven internally by a gear?

what we're discussing here is like a starter ring gear but where the teeth
are inside and has a large enough diameter to accomodate some sort of
driving gear and a structual member not in contact with the ring gear. The
ring gear would then be attached to the prop with the very large center
hole.

Our first thought were the gears inside a auto rear end (connecting drive
shaft to axle shaft) but instead of being at right angles, looking for
driving and driven gears to be inline.

Didn't some old fighterplanes fire through the prop and spinner? How did
that work?

Thanks, Dick

[[email protected]]

On Fri, 26 Nov 2004 00:01:47 GMT, "Dick" > wrote:

>Has anyone seen or heard of a propellor with the center hole being maybe a
>10" diameter so that the prop could be driven internally by a gear?
>
>what we're discussing here is like a starter ring gear but where the teeth
>are inside and has a large enough diameter to accomodate some sort of
>driving gear and a structual member not in contact with the ring gear. The
>ring gear would then be attached to the prop with the very large center
>hole.
>
>Our first thought were the gears inside a auto rear end (connecting drive
>shaft to axle shaft) but instead of being at right angles, looking for
>driving and driven gears to be inline.
>
>Didn't some old fighterplanes fire through the prop and spinner? How did
>that work?
>
>Thanks, Dick
>
You don't want it that big in the prop, and you need some way of
supporting the prop and gear. A bearing that big is both heavy and
expensive.

However, the same system design is used in the Marcotte redrive, made
in Quebec. It is a well engineered, high quality unit.

[Dick]

Perhaps more info after looking at the Marcotte redrive and seeing the
external teeth for the belt would help.

Our basic thought was: [1] the aft tube supporting a sailplane's tail and
[2] the possibility of having a "ring" gear (with teeth facing inside)
revolving around the outside of the tube but not touching as an auto type
wheel bearing rotates about the fixed axle. The ring gear would somehow be
connected to a pro hub with blades similiar to those seen inside a jet
engine intake.

We thought the "open" inside area of the ring gear would have to be large
enough for a driving gear and 2 idlers to hold the ring gear inplace.

Instead of a convential pusher prop setup to avoid the tail & control
surfaces via a high mounted engine or twin tail fuselage booms, the
aforementioned thought bubbled up during an after-Turkey-dinner.

This may be a turkey idea but still discussing as wives sale shop <G>. Dick
> wrote in message
...
> On Fri, 26 Nov 2004 00:01:47 GMT, "Dick" > wrote:
>
>>Has anyone seen or heard of a propellor with the center hole being maybe a
>>10" diameter so that the prop could be driven internally by a gear?
>>
>>what we're discussing here is like a starter ring gear but where the teeth
>>are inside and has a large enough diameter to accomodate some sort of
>>driving gear and a structual member not in contact with the ring gear.
>>The
>>ring gear would then be attached to the prop with the very large center
>>hole.
>>
>>Our first thought were the gears inside a auto rear end (connecting drive
>>shaft to axle shaft) but instead of being at right angles, looking for
>>driving and driven gears to be inline.
>>
>>Didn't some old fighterplanes fire through the prop and spinner? How did
>>that work?
>>
>>Thanks, Dick
>>
> You don't want it that big in the prop, and you need some way of
> supporting the prop and gear. A bearing that big is both heavy and
> expensive.
>
> However, the same system design is used in the Marcotte redrive, made
> in Quebec. It is a well engineered, high quality unit.

[Dan Thomas]

"Dick" > wrote in message >...
>
> Didn't some old fighterplanes fire through the prop and spinner? How did
> that work?
>
> Thanks, Dick

The prop was on a hollow shaft driven by a spur gear, so that the
input gearing was out of the way. The gun fired through the hollow
shaft. Some German airplanes had this, I think, and the P-63 Airacobra
did too.

Dan

[Andy Asberry]

On Fri, 26 Nov 2004 00:01:47 GMT, "Dick" > wrote:

>Has anyone seen or heard of a propellor with the center hole being maybe a
>10" diameter so that the prop could be driven internally by a gear?
>
>what we're discussing here is like a starter ring gear but where the teeth
>are inside and has a large enough diameter to accomodate some sort of
>driving gear and a structual member not in contact with the ring gear. The
>ring gear would then be attached to the prop with the very large center
>hole.
>
>Our first thought were the gears inside a auto rear end (connecting drive
>shaft to axle shaft) but instead of being at right angles, looking for
>driving and driven gears to be inline.
>
>Didn't some old fighterplanes fire through the prop and spinner? How did
>that work?
>
>Thanks, Dick
>

Some 20 odd years ago, I saw an ultralight with the prop fitted around
the boom tube. I don't recall if it was at SNF or Oshkosh. It was belt
driven IIRC. I'll bet Chuck remembers.

[Dick]

now that is exactly the kind of thing that we were discussing. Hope someone
can find a picture.
"Andy Asberry" > wrote in message
...
> On Fri, 26 Nov 2004 00:01:47 GMT, "Dick" > wrote:
>
>>Has anyone seen or heard of a propellor with the center hole being maybe a
>>10" diameter so that the prop could be driven internally by a gear?
>>
>>what we're discussing here is like a starter ring gear but where the teeth
>>are inside and has a large enough diameter to accomodate some sort of
>>driving gear and a structual member not in contact with the ring gear.
>>The
>>ring gear would then be attached to the prop with the very large center
>>hole.
>>
>>Our first thought were the gears inside a auto rear end (connecting drive
>>shaft to axle shaft) but instead of being at right angles, looking for
>>driving and driven gears to be inline.
>>
>>Didn't some old fighterplanes fire through the prop and spinner? How did
>>that work?
>>
>>Thanks, Dick
>>
>
> Some 20 odd years ago, I saw an ultralight with the prop fitted around
> the boom tube. I don't recall if it was at SNF or Oshkosh. It was belt
> driven IIRC. I'll bet Chuck remembers.