OS 91FX

[Nat Penton]

Ihncheol-      The 17X10N cut to 16 is slightly less load than the  16X10.
Some time ago I measured the thrust @ 13+ lbs with the 2 blade and 11+ with
the 4 bl, 20% nitro. Occasionally I run the 17X10N uncut. I rarely check
rpms, just performance. The main problem we all have, I believe, is engine
mounts. What we have availible may be allright for the four strokes, I dont
really know, but it is not for the two strokes. I'm working on that. Damn
they fly good when you get good isolation . The 91SX-H gave me a little
problem with carb seal, also the short shaft is a pain. Can't tell
difference otherwise.
----- Original Message -----
From: "Ihncheol Park" <PatternFlyer at msn.com>
To: <discussion at nsrca.org>
Sent: Sunday, October 26, 2003 1:46 AM
Subject: RE: OS 91FX


> Nat,
>
> What are the differences between running the 17x10N cut down to 16" and
> normal 16x10?
> Also, from a pro_performance spreadsheet which I downloaded from a
website.
> Thrust = 2.83E-12 x RPM^2 x D^4
>
> 15x8 @ 10K rpm (actually running rpm): 15.9 pound of thrust show up.
> 17x10 @7800 : 15.96 pound
> 16x10 @8000 : 13.18 pound
>
> Not really sure if the equation is meaningful at the actual running.
> Are you using the larger diameter prop to reduce noise?
> I also heard you were using 91SX-H.
>
> Ihncheol Park
>
> -----Original Message-----
> From: discussion-request at nsrca.org
> [mailto:discussion-request at nsrca.org]On Behalf Of Nat Penton
> Sent: Saturday, October 25, 2003 10:25 PM
> To: discussion at nsrca.org
> Subject: Re: OS 91FX
>
>
> Matt I will add additional  info. Have been running the 91FX over two
years
> and it will carry my 8+ lb airplanes to the moon. On fuel - was using
> Ritches 20%, now 30%,idles under 1500. Pipe length- 26 to 28" depending on
> which pipe, most power from ES 2 stk(1 9/16 OD), Favorite props 17X10N cut
> to16" and 15.5X12, rpms around 7700. Using Hanno (same as 140RX) backplate
> pump. Can be installed with simple tools and a little ingenuity. O yes 2
> headshims. Stock bearings good for about 30 flts, Boca sealed well over
100,
> leave all seals in place. Provide crankcase cooling for longer bearing
life.
> Have not tried 15CC Hatori or MACS but plan to. Headers are from Karl
> Mueller,very nice.
> ----- Original Message -----
> From: "David Gundling" <DGundling at compuserve.com>
> To: <discussion at nsrca.org>
> Sent: Saturday, October 25, 2003 8:34 AM
> Subject: Re: OS 91FX
>
>
> > Message text written by INTERNET:discussion at nsrca.org
> > >The 91 FX is stronger than the ys 91 4 cycle with some margin. Stretch
> the
> >
> > pipe a bit with an extra long header and run the larger prop. The set-up
> > will
> > amaze you with its output and quietness. Good friend Nat is using it on
> his
> >
> > X-Press turning a 17x10 N cut down 1/2 inch. Plenty of power for the 8-9
> > pound
> > plane.
> >
> > Matt K<
> >
> > Matt,
> >
> > Thanks.
> >
> > Dave
> > # To be removed from this list, send a message to
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> > #
> >
> >
> >
>
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