I just stumbled across this planetary PSRU on
www.barnstormers.com, I case your looking.
Erik
By the way, I am NOT the seller.
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RD-1C 2.85 PSRU (LH ROT) ? $2,500 ? AVAILABLE FOR SALE
? new, but never run. handles 400+hp, fits mazda 13B &
20B engines. lost med. send for pics ? Contact Kevin
Lane - located Portland, OR USA ? Telephone: 503 233
1818 ? Posted September 5, 2005
-------------------------------------------------------
Tracy's site says the RD-1C is good to 300hp..
http://www.rotaryaviation.com/RD-1C.htm
Has that number been updated (upgraded) elsewhere?
Matt-
Should have no problem with that much HP. The Ford A4OD six pinion
gear set is used behind the Ford F250 Power Stroke V8 turbo diesel
with 600 foot pounds of torque. Max torque on a 3 rotor side intake
port engine is about 240 foot pounds. However that is assuming
you keep the oil cool.
BTW the torque out of the prop end in case anybody still thinks
airplanes fly on torque is 685 foot pounds.
HP = T x RPM / 5252 therefor HP x 5252 / RPM = input torque
400 HP at 8000 RPM would then be only 263 foot pounds input torque.
400 HP at 7000 RPM would be 300 foot pounds in case you are turbo
charged.
I know you know this Matt. It is for some of our new subscribers.
Paul Lamar
Paul
I've seen these calculations before. The Ford pinion gear set is
used in the
rear end of the truck correct? It bothers me comparing the torque
seen out
of a truck engine before the transmission in a low duty cycle
vehicle with
the torque the Ford gear set experiences connected to large prop having
transient loads in flight. Wouldn't an analogy be trying to spin the
tires
of the truck on a gravel road with a heavy load. Quite a shock to the
helical gears right?
Didn't Dave just experience a failure because of a backfiring engine.
I am not saying the RD 1C won't handle 300+ hp but I am concerned
enough to
want it tested somehow. Straight gear ala Mistral's unit would be more
robust. More gear contact surface area. Perhaps when Tom Parks is
successfully flying with his RD 1C unit we will all have a better idea.
Doug in Japan
Not in the rear end. In an automatic transmission.
Dave's failure had to do with how the sun gear was welded to the
input shaft.
Tracy has changed the method by switching to a pin. Ideally it could be
two pins. See the illustration. My calculation assumes the sun gear and
input shaft are connected together in a manner that achieves the
intrinsic
strength of both the input shaft and the sun gear.
In theory helical gears of a given width are stronger than straight
cut gears of the same width. This is because the all important line
contact length is longer.
If you want a bullet proof 45 pound PSRU with 1000 HP capility get
your self a Bell 47 helicopter final drive. Fits the rotary
like a glove.
Paul Lamar
How difficult is it to find a Bell 47 final drive, and what do you
suppose it might cost? Sounds like it would work great on an aerobatic
Steen Skybolt with a P-port 20B.
Jim Kidd, Mequon WI
http://www.bell47asap.com/
http://www.bell47helicopterassociation.org/BELL%2047%20PARTS.htm
Try google. Just two out of 485,000
Paul Lamar
The second url has many parts suppliers even one in Australia George hint
hint. The obvious question I haven't asked yet is what is the reduction
ratio on this PSRU?
Doug in Japan
Somebody better price one of these things before you get
too carried away :)
Paul Lamar
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