Thanks very much for the information and advice on the front mounts. One
issue I still have to deal with is the CG. The engine needs to be as far
forward as
possible in order to avoid adding weight in the nose to stay in W&B. A
3" (or 2") 90-degree angle in front of the engine will space it a little
farther aft
than ideal.
Scott Gettings
Well you can always use a Schertz beam under the front (car) end housing.
Not the front cover. The front end housing.
That will move it well forward. What about the prop location and cowl?
Will that still fit with the engine moved one inch aft? If you move it
two or three inches forward will it still fit?
BTW with the engine moved one inch aft of a point... that is a moment of
300 inch pounds.
That can be balanced CG wise by having ten pounds 30 inches forward of
that
point. In other words it all depends on what type of shoes you are wearing
and the shoe size you wear :) Hiking boots might move the CG too far
forward :)
Sorry about the lame attempt at humor. If it is 50 inches forward of that
point
it only requires six pounds to balance. Where is the battery?
We still need to talk about the rear mounts.
BTW here is the way Rino Lacomb did it. I have a lot more pictures if you
need
them.
Paul Lamar
Paul,
Speaking of CG, I was originally concerned about the weight of the Mazda
Rotor engine in the Vision which has a firewall forward limit of 300 lbs.
I know there are a number of ways to off-set the difference between this
limit and the 13 B all-up weight.
The method I prefer is to move the wing position forward so as to minimize
the installation requiring the battery behind the pilot with all the wire or
extra weight in the tail etc.
I did ask the designer if this could be achieve and he agreed that it could.
I suggested that a poor designed engine package could weight up to 400 lbs
with 2 batteries intercooler turbo etc. His calculations indicated that an
extra 100 lbs would require a forward movement of the wings of 4".
I understand these changes can affect the dynamics of the elevator and
rudder, making them more sensitive to pilot inputs, so I wouldn't want to
move beyond that and 400 lbs is a good round number. If I built to that
standard I could always lengthen the engine mounts if the weight was
significantly lower. I could always make the distance 2" for a 350 lb
package etc.
My question is how does one calculate the distance of the wing movement, in
these circumstances, to confirm wing positions.
George ( down under)
You mean as far as the new CG calculations are concerned or the effect it has
on the handling characteristics?
To calculate the new CG position you need to know the weight of the wing.
Not something that is easy to come up with unless it is already built.
Paul Lamar
The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2004 All world wide rights reserved.