🚀 go-pugleaf

> |A bushing motor like the OS .40 FP has much less power (about the
> |same power as strong .25" motor) than an equivalent ball bearing motor.

> I would strongly disagree with this.  The only difference between a ball-
> bearing motor and a sleeve bearing motor is the bearings.  Ball bearings
> do not have significantly less drag, they just last longer and can take
> greater stress.  But the FP is a Schnuerle ported engine, and produces
> as much power as any other 40, excepting that you cannot safely stress
> them with high nitro or tuned pipe.

Bzzzzzzzt! Wrong!

The manufacturers specs for the 40 FP as shown in the Tower catalog
show the 40 FP at about 1 hp.  Now this is probably more than most
25's which tend to be about .8 or so.  But this is definitely *less*
than most ball bearing schnuerle 40's, heck my OS 32 F spec's out with
*more* power than a 40 FP.

As mentioned by another poster, the port timing is often reduced in
budget/sport engines to reduce performance and to increase general
tolerance to abuse.  Another item specifically changed on the 40 FP
is the carburetor:  it has a *much* smaller throat diameter than the
other 40 sized OS engines.  The muffler is also smaller: the 40 FP
uses the same muffler as the 32 F which has the same bolt pattern as
the 25 FSR (so for a tuned pipe use one for a 25?).

The 40 FP will save money in the short term... but if a newbie wants
more power in the future (different plane, aerobatics, etc.) then
I just don't see how it is cheaper to buy *two* engines of any type
than to buy *one* good engine.

Steve Jahr
jahr@hprnd.rose.hp.com