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Thanks, everyone. Consensus seems to be "try the thrust change"....
and I'll do that. Good points and things to refresh memory about
dynamic effects when changing throttle settings.
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Happy Monday!
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Bob<br>---- "george w. kennie" <geobet@gis.net> wrote:<br>
>IMO it sounds like the center line of the engine shaft is above the center
line of the wing acting like down thrust. Additionally, as I recall,
don't those Yaks have really long gear legs, ?......this would produce
additional drag producing even more down thrust effect, then when you
cut the power all of these force factors are effectively removed,
which the elev setting has been overpowering at normal R.P.M. Without
these factors in effect, the up elev now produces enough force to
cause ballooning at the reduced setting. You will probably need to add
a couple of degrees of up-thrust in the engine and this should not
make it pitch to the belly, if anything I would expect it to
exacerbate the canopy pitch requiring additional corrective mix, but
like I say, just MO.<br>>G.<br>><br>><br>>----- Original
Message -----<br>>From: Bob Pastorello<br>>To: NSRCA Mailing List<br>
>Sent: Monday, May 22, 2006 6:53 AM<br>>Subject: [NSRCA-discussion] Thrust
Line Trimming<br>><br>><br>>Hello - I have a BME 30% Yak, (and
had a TOC/Aviation Models Yak), and both pitch to the canopy when
power is reduced in vertical climbs (also on level cruise power
deceleration, too). Elsewhere, fly well, and doesn't exhibit bizarre
incidence problems, and both needed UP elev. trim for level upright
flight.<br>><br>>ON the RCU threads on these two, owners report
needing to carry up elev trim, also, but haven't gotten any insights
on the engine thrust question.<br>><br>>I have measured, and there
is currently NO up or down thrust in the motor referenced to
centerline.<br>><br>>Could these planes actually need some UP
thrust??<br>><br>>Bob Pastorello<br>>www.rcaerobats.net<br>
>rcaerobob@cox.net<br>><br>><br>
>------------------------------------------------------------------------------
<br>><br>><br>>_______________________________________________<br>
>NSRCA-discussion mailing list<br>>NSRCA-discussion@lists.nsrca.org<br>
>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion<br><br>--<br>Bob
Pastorello, El Reno, OK, USA<br>rcaerobob@cox.net<br>www.rcaerobats.net<br>
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