Good morning Paul

I am sending you a sketch the way i am looking the reduction
angle drive with all components ,check it and come back on
your own view

Jean Prudhomme

Nice sketch Jean.

I took the liberty of modifying it the way I think it should be done.

IMHO using u-joints on the prop shaft adds unnecessary weight and
torsional flexibility.

It is up to you of course.

Paul Lamar

Ok Paul do you have any reference of those helicopter bearing and also
could you make a sketch of the complete prop shaft,by the way the main
gear will be at your place in one day and the rest in 3 days
Regarding the prop governer it can be feed true the casing to the
back of housing and fee pressure true middle of the prop shaft.

What is the effect of carbon fiber components to be imbedded all
the time on warm oil???

Jean Prudhomme

I don't know but it is really risky. I did not know you wanted hydraulic
constant speed props. That opens a whole new can of worms. There would
be a lot of oil in a 3 foot long 3.5 inch diameter hollow carbon
 fiber prop shaft.  200 F oil is bound to have a serious effect on
 the strength of the epoxy.

Here is some stuff on helicopter AKA thin section bearings.
http://www.timken.com/en-us/Pages/Home.aspx
http://www.timken.com/en-us/products/Pages/Catalogs.aspx

Paul Lamar

 So we have to use steel shaft as prop shaft because
 this gear set have to run in oil same as differential
 to lubricate those bearings we are concern with 7000rpm
 pinion, the carbon fiber tubing will not do the job

 Jean Prudhomme

 No like the RX8 the carbon fiber prop shaft is thermally isolated
 from the gear box. Yes the gear box does need to run in oil
 but if you are going to move the hot oil from the gear box to the
 prop it needs to go down the prop shaft. You need to make a sketch
 of exactly how you are going to get the oil into and out of the prop
 through the the prop shaft.

 IMHO this is getting far too complex with two many parts.

 Where is the payback compared to just using two engines
 with PSRU's on the wings?

 Paul Lamar


You could run a 1/2" SS or AL tube inside a 3/4 tube to get oil to and
from
the prop. Seals on both side of the hypoid gears will keep that oil
where it
supposed to be. Just more complex!

Dale Davies

That is a pretty good idea.

Paul Lamar



I'll probably get blasted for this idea, but here goes:

Since this configuration sends power to the PSRU through a shaft, how
about making a centrifugal compressor rotor as a replacement for the
flywheel?  Supercharge with a reduced weight penalty being the benefit.

Mike
-

As well you should :)
Common Mike. I know you know, as an engineer, there is no free lunch
when you super charge. To Quote P&W:

"Nevertheless, even proponents of mechanical superchargers were
aware of the drawbacks of the concept. The largest of these was
that it took a considerable amount of the engine's power to
drive the internal supercharger."


Paul Lamar