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Just a little additional input here. This off-set to the left thing doesn't
seem to me to be as pronounced as many seem to be implying. My Hyde type
mount is 1/2"off center on the firewall, but the buggar is almost
an inch thick and the engine doesn't sit up against the puck to allow line
clearance, so at that distance from the firewall the off-center distance
is less than 3/8" which puts almost 2&3/4" of the shaft to the right
of center. Now I grant you that the segment to the left of center is heavier,
but by how much? The whole shaft weighs 5.6 ounces.If we say that 3/4 of
the weight is to the left of center, then there is 4.2 ounces left of center
and 1.4 oz. to the right of center.Don't forget that this monster has a
spinner and a prop bolted to it's long end and they total somewhere in
the neighborhood of 7 ounces. Let' see now 7 plus 1.4 equals 8.4 ounces
right of center and 4.2 ounces left of center.Hmmm,....Oh yeah, lets not
forget that there's a header contributing to the picture also. Its hanging
off the left side of the aircraft and it weighs 1.2 ounces,
so now we have 5.4 on the left and 8.4 on the right, so we've narrowed
it down to only a 3 ounce differential.Now I really don't know if it affects
our execution of snaps or tight high-G corners, but I think that the
aircraft is still in a state of dynamic imbalance. I think that I
can come awfully close by statically balancing, but is it perfect? I don't
think it's even close.And I also think that if you could fly an aircraft
that was in perfect dynamic balance, you would really be able to tell the
difference and it wouldn't take someone with the ability of a Troy to be
overwhelmed with awe.
<br>I remember when setting up my first Heli that the instructions emphasized
balancing the blades, and they didn't want you to just hook up the blades
to the blade holders and the shaft and balance the whole thing as a unit,
but the individual blades were to be balanced against each other to be
absolutely certain that the balance point was at exactly the same distance
out on each blade. Otherwise the dynamics would be off, even though the
head, as a unit, was in balance.
<br>Just a little more grist for the mill.
<br>Georgie
<p>Bob Pastorello wrote:
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<font face="Arial"><font size=-1>Nat,
I'd tend to agree - the moment arm of the mass offset is so minimally-different
from a conventional inverted motor. Actually, some mass moment would
actually move CLOSER to longitudinal centerline with a side-mounted motor,
thus reducing the dynamic imbalance. As someone else pointed out,
we statically-balance with a mass offset left of center.</font></font><font face="Arial"><font size=-1>
How little difference could there actually be?</font></font><font face="Arial"><font size=-1>
Maybe tenths of an ounce in moment?</font></font>
<br>Bob Pastorello, Oklahoma
<br>NSRCA 199, AMA 46373
<br><a href="mailto:rcaerobob@cox.net">rcaerobob@cox.net</a>
<br><a href="http://www.rcaerobats.net">www.rcaerobats.net</a>
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<div style="FONT: 10pt arial">----- Original Message -----</div>
<div
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><b>From:</b>
<a href="mailto:natpenton@centurytel.net" title="natpenton@centurytel.net">Nat
Penton</a></div>
<div style="FONT: 10pt arial"><b>To:</b> <a href="mailto:discussion@nsrca.org" title="discussion@nsrca.org">discussion@nsrca.org</a></div>
<div style="FONT: 10pt arial"><b>Sent:</b> Wednesday, January 14, 2004
9:02 PM</div>
<div style="FONT: 10pt arial"><b>Subject:</b> Re: Sideways engine?</div>
<font face="Arial"><font size=-1>If lateral balance is attained with
assymetric weight distribution then the plane would be dynamically unbalanced,
that is there would be assymetric forces during accelerated roll . I suppose
this might be noticeable with significant assymetric weight distribution,
but probably not with what we are talking about. Mike Nauman where are
you ?</font></font></blockquote>
</blockquote>
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