Talwheel Notes

Mark Boyd, 10/18/02


For these notes, I assume the reader has already read
"The Compleat Taildragger Pilot," or a similar book.  These
notes cover subjects not explained fully in these books.

1.  Since the tailwheel airplane has C.G. behind the mains,
it is unstable on landing and tries to swap ends.  Why not
just make the C.G. more forward?  Lots of reasons.

  First, the plane needs some rear C.G. or it will tip over
if you apply heavy braking.  Next, you'll run out of elevator
back pressure if the C.G. is further forward.  Aft C.G. gives
more momentum when the side to side oscillations start, but
also helps get the tail down.

2.  When soloing, the instructor either gets out of the front
seat (cub) or the back seat (champ).  The C.G. at this point 
will change.  For a cub it moves aft, meaning stall speed 
decreases, yaw oscillations have more momentum, and elevator
is very effective for getting and keeping the tail on the 
ground.  For a champ, the opposite is true.  Stall speed 
increases, the airplane is less yaw unstable, and more
back pressure is needed to get and keep the tail on the 
ground. 

3.  Why do tailwheel planes have so much adverse yaw?
Adverse yaw helps crosswind landing.  Think about it.
The raised wing is causing a lot of drag, which is helping 
to counteract the weathervaning.

  This is why planes with more adverse yaw (big ailerons
far out on the wings) have good crosswind components.

4.  Two experiences I've had with tailwheel airplanes
have been exciting.

  In the first, I was shutting down my plane to push it back
for parking.  A tailwheel pilot was on the taxiway at RHV,
taxiing by fairly fast, very close, and without any S turns
at all.  
  At about three feet from my airplane, he finally saw 
it, and slammed on both brakes.  The plane tipped up, and
hung for a split second, and then hit the prop and stood on
it's nose.  
  Fuel poured out the nose, and I was a bit
scared for the pilot.  But I focussed on carefully shutting 
down my own plane.  The pilot eventually shut off the
fuel and got out of the plane.  We carefully helped him
lower the tail with a rope.
  When I did my tailwheel training, I once heard on the
radio "what is that big slow yellow turtle on the taxiway,"   
and that was ME!  I was terribly slow and had lots of S
turns when I would taxi.  I didn't trust the brakes too
much, either.

  My second tailwheel excitement was on my first tailwheel
solo.  I got the champ started fine, taxied out, and took
off.  No problem so far.  I come in for a landing with about
a 3-5 knot crosswind.  I do my usual flare, and I've
learned not to pull all the way back or I hit the tail on 
landing.  
  But with the instructor not in the plane, this
means the tail is about a foot in the air.  This is out
of the propwash and so the rudder is less effective.
So now I have full aileron left and full right rudder,
but I'm confused why the tailwheel isn't touching.
  Fortunately the adverse yaw saves the plane.  With
full aileron, the plane stays pretty straight.  I 
roll out on just the left wheel, and at about 10 knots,
the other wheel and the tailwheel touch down and
everything is normal again.
  So I do it two more times, this time with the stick
all the way back for landing, and everything is fine.