Al Gietzen wrote:

This [403 lbs.] is not much heavier than an IO360 installation, and I estimate the CG
a couple of inches further forward than the Lyc, resulting in a moment for the engine
package that is very close to being the same.  Definitely lighter than [an] IO 540.

Russell Kent responded:

Further forward than the IO-360 installation?  Don't you mean further rearward? Or did
you mean further forward than the heavier IO-540 installation?

Paul Lamar responded:

It's a pusher Russell. That is the problem when people don't respond by putting their
messages at the end of the old message. From just the Subject heading you would no
necessarily know that.

No, I knew Al was referring to the pusher Velocity aircraft.  What I don't get (and
perhaps I don't understand C of G), is that making the tail heavier (20B vs IO-360)
moves the center of mass towards the tail (i.e. "rearwards"). Center of mass and center
of gravity are essentially the same here, correct?

Russell Kent

CG of the engine or CG of the airplane? If the CG of the engine (which is 
what I think Al was referring too) moves forward so too does the CG of
the aircraft. What Al was saying (I think) is the CG of the heavier rotary engine moves
forward reducing the moment about the reference line (usually the the nose of the
aircraft) and giving the same CG location to the aircraft.

Paul Lamar

 
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