If you ever wanted to know what a Bell 47 Helicopter gear box looks
 like take a look at this.



http://cgi.ebay.com/ebaymotors/BELL-47-M-R-transmission-helicopter-part-/320585434705

 The price is a bit steep so this is probably as close as I will ever get
to
 one.

 Erik

 Here are some pictures I took when adapted to a rotary.

 Paul Lamar

 Paul,

I didn't see a torque damper in the pictures?  Does it even have one?  Do
you have any pictures?

The prop attachment seems a little flimsy.  Is this a tapered shaft or
what?

Mark

No torque damper. Dave Garber had some Bell engineers check it
for 6000 RPM input and they said it was good to 1000 HP.

The prop shaft is probably the weak link as I don't think
any calculations were made on the gyro reactions due to A/C stall
or spin situations. One needs widely separated ball or roller
bearings to deal with gyro bending moments of up to 600 foot pounds.

I borrowed the airplane from Dave and ran it up at Sun n Fun
in 2005. 45 inches of HG was Dave Garbers imposed limit.
Estimated power was 350 HP each of two engines at 6500 RPM.
It could blow down trees :) Well over 400 HP has been had
from turbo 13B's running on gasoline and higher RPM's.

Paul Lamar




Paul,   I bought an F350 super duty Ford transfer case planetary last week
on e-Bay for $87.50 with free shipping. It is from a 4407 series and the
ratio is 2.72 to 1.   The sun gear and six pinion planetary weigh 10-1/4
pounds the ring gear 2 pounds and the input splined range adapter is 1/2
pound, total  12-3/4 pounds.  The planet orbit diameter is 4.99" and the
ring gear pitch diameter is     6.239" with an OD of 7.022"  The planet
gears are helical and have a width of 1.123" Torque capacity is much higher
than the E4OD since it sees the 2.85 torque multiplication of the
transmission.  As expected it shows no wear because it is only engaged when
the 4 wheel drive is in low lock. It doesn't look like any machine work will
be necessary on these parts but if I use the stock mainshaft that will need
shortened. The range gear slider which inputs to the planetary has a large
fine tooth spline and there are some bearing seats on the shaft that make
it  usefull. I figure a hollow output propshaft over the output spindle of
the planetary carrier. The intended application is on a turbocharged
quadrotor which might get me out of my comfort zone with the E4OD output
shaft diameter. Possibly someone will start making  something with a
constant speed prop before I need it, if not this looks like a good choice
so far.

george grimes

Take some pictures George. Sounds good.

Paul Lamar