effect of changed thrust line.

On Fri, 14 Nov 2008 16:16:21 -0600, cavelamb himself
wrote:

wrote:


Lowering the thrust line to below the center of aerodynamic drag would
cause nose up - OK I get that. Now where is the center of drag on a
peg? and it will DEFINETLY change with flying attitude - ie with the
flaps on, or the slats extended.

I guess what it boils down to is it will not be a HUGE effect.
On a 28" long engine, 3 degrees is roughly 1.5" offset, so 1/4" is
roughly 1/2 degree. One 1/8" washer at the firewall and one at the
engine rubber on both sides will make 1/2 degree change if I need to
do a bit od "fine" tuning.

Spec for the O200 mount is 1.5 degrees down IIRC,amounting to .75"
offset - guess I'll put in about .875 and see what happens

I thought about this a bit last night.
And a couple of thoughts seemed worth relaying.

First, (and most obviously) a new mount will be needed.
So build it as close as you can guess to what you'll need.

Adjusting the mount at the firewall end strikes me as a bit "iffy".

More that a washer or two makes for a noticeable misalignment between top
and bottom bolts. When torqued down, something it GOING to give.

Either the mount gets twisted or the firewall support structure does.
Or both?

The engine end, if rubber cushioned would be a lot more compliant.
Might consider all that when designing the new mount.

The Corvair would use a bearer style mount, wouldn't it?

Not on this plane. I'll get pics of the mount design on line soon.
I've put mounting tabs on the top and bottom rear so I'm mounting it
like a Conti O200, but using 1" diameter Licoming type homebuilder
mounts.The typical bed mount would interfere with my 180 degree header
system.

Rubber pads front and rear would give quite a bit of adjustment room.

I think Stealth got it right.

Same side alignment and a touch more down.