Bob, if there is any pull to the right then its more than offset by the yaw
to the left caused by (take your pick) 1. Torque 2. "P" Factor 3. Air Swirl
{:>). It may be that the small difference in an already fairly light
prop does not have a lot of impact. On the other hand there may a Lot of
gyroscopic precession when I rotate and that is what keeps me on the runway
heading (more or less){:>)
----- Original Message -----
Sent: Monday, December 12, 2005 11:42
AM
Subject: [FlyRotary] Re: "P" factor? Re:
Static Engine RPM
Ed,
Not being the number crunching type, where
does Gyroscopic Precession come in to play? With the larger prop, do you
notice any effect when the nose is rotated up? The way I picture it,
there should be some momentary pull to the right.
Bob Perkinson
Hendersonville, TN.
RV9 N658RP
Reserved
If nothing changes
Nothing changes
No familiar with the SA-16, Bob, but are both props turning same
direction or opposite - would make a significant difference in whether there
is a swirl (my spell checker says OK {:>)) effect or not. If in
opposite directions then I would agree, if both props rotating in same
direction then harder to say.
For a long time I thought that Torque was the major cause, however, I
remain convinced (at this point) that the low rolling and large yaw force is
primarily caused by swirl. Having encountered prop swirl on take off roll
too close behind Finn's RV3 there is no question in my mind that prop swirl
is a powerful force. But, regardless whether torque or swirl (or
combination), the 2.85 gear box and larger prop makes a considerable
change.
I don't recall whether Tracy adjusted his motor mount for his 2.85 and
larger prop or not.
Ed A