"MrV" wrote in message
oups.com...
truthfully the idea is to make an OKAY craft. i'm thinking 150 to
160kts with okay fuel burn.
now if i'm right i'd be running the tranny in like 4th gear. isn't
this where its designed to spend a good deal of its time ?

if i remember right, a car engine's output is not perfectly circular
its kinda eccentric. and something is neccessary to convert the
irregular motion into the circular motion for the prop


If you are thinking of the top gear in a trans with overdrive, the overdrive
isn't designed for high torques (read the owners manual - "do not tow
trailers in overdrive"). Plus it will speed the prop, not slow it down. If
you are thinking 4th out of 5 gears in the typical trans with overdrive,
then you have direct drive - not much pont in bolting on a trans just to get
out what you put in, eh?

The auto trans has everything you don't want and nothing you do. No gears
would be a better choice than the wrong gears.

The torque output is not exactly constant, but the flywheel damps most of
that out. A propeller, on the other hand generates torque pulses as it goes
by cowling and stuff - that can cause problems if you are trying to run a
drive shaft. Pusher aircraft are "worst case". Note that most piston engine
aircraft have the prop bolted right on the end of the crankshaft - nothing
required to account for the torque pulses from the engine (Ignoring the
cases where you excite the resonant frequencies of the prop).

--
Geoff
the sea hawk at wow way d0t com
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