🚀 go-pugleaf

From article <C0CnzE.Gn1@icon.rose.hp.com>, by jahr@hprnd.rose.hp.com (Steve Jahr):
>> |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.

I started with the 40FP on a 60" wingspan trainer, and progressed with
the same engine to a Skat Kat 500 racer.  It certainly flies well enough
for *most* aerobatics, but was slightly underpowered on my trainer.
I am satisfied with it on the Skat Kat for sport use/weekend flying,
but I am well aware that any BB 40 (Fox, Nelson etc) racing engine
completely leaves the FP in the DUST.