LJ wrote:
Not realy.I don't know what your asken me?

Ernest Christley wrote:

LJ wrote:

Also level the plane as it would fly though the air.Only my $0.02.
LJ


And use the measurement to the engines CG. You do know where the CG
is on each of the engines, don't you?



CG isn't something unique to airplanes. Every object within the reach
of gravity has a 3-dimensional point where all the objects weight could
be thought of as being concentrated...engines included.

Take the riduculous case. You have an aircraft engine that stretches
from station 8 to station 10, as the designer put it on paper. The
engine weighs 100# and the CG is at the center. The moment arm is 900.

But you want to substitute the new SuperRev engine, 'cause it only
weighs 75#. 900/75 = 12, so you need to move the engine out 3 stations.
Now the engine will stretch from station 11 to 13. Now what if it is
the same length, but somehow all the weight got concentrated in the
front end. The front end would need to be placed on station 12, and the
back end would be on station 10.

Engines are not homogeneous chunks of metal, and the CG can vary
considerably from one configuration to another. When I bought my
rotary, it was nice and balanced around the center. When I removed the
manual flywheel (~30#) the thing practically flipped up onto the other end.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."