V. E. Welch wrote:

For you gentlemen that are currently running rotaries that have been
substituted for lycomings; how did you determine the location of the thrust
line in order to correctly fabricate your motor mounts?

Vince
RV-8A
under construction

One way of doing it is put the cowl on there and use
a string and  a level to mark a place on the firewall based 
on the prop hole in the cowl. 

You can also set the tail up with the firewall vertical
and use a clear plastic tube with water to locate the center
of the hole in the cowl and a corresponding point on the 
firewall.

Some designs use about a degree and a half of downthrust on 
a tractor. Some use a little side thrust.
 
Paul Lamar
 
The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org