CG hook on aerotows -- the followup

Well, that was certainly an informative and oft entertaining set of replies
from my post a week++ ago. I think the combined experience of everyone who
responded would add up to a number even Carl Sagan would admire. I thank
everyone who took the time to respond to my original question; all the other
stuff was bonus material.

A number of pilots, some by direct e-mail, pointed out that when correcting
for a dipped wing during the early part of take-off, rudder and not aileron
should be used. I fully understand the reason behind this (it wasn't
overlooked in my training), however, my question was about the Pilatus B-4
in particular. This glider, unlike the five or six others I've flown since I
started (2-33, 1-26, L-33, 1-36, G-103, SK-21, and more than a few chairs),
has significant weight on the tail while sitting on the ground, which with
my light weight in front requires a fairly good airspeed to pick up off the
ground, even with the stick all the way forward. Alas, until the tail is off
the ground, full rudder deflection doesn't do squat!!!.

I was reminded of this again this last Sunday, when I flew the B-4 with a
significant crosswind component. On one particular take-off, I started with
the main/tail-wheel line a few degrees off the runway centerline. Sure
enough, a wing started dipping, to which I instinctively applied opposite
rudder, which didn't do a thing until the tail started to fly, and when that
happened, my off-center heading was suddenly a lot worse.

The situation described above does not seem to have an unambiguous way to
handle it. Am I wrong, or is the best hope to keep the fingers crossed and
on the release handle?

-ted

"Ted Wagner" wrote in message .. .

snip


The situation described above does not seem to have an unambiguous way to
handle it. Am I wrong, or is the best hope to keep the fingers crossed and
on the release handle?

-ted

Many standard class pilots have found that use of partial airbrakes
during the early part of the takeoff roll will greatly improve aileron
effectiveness and help to prevent wing drop. It's a long time since I
flew a B4 and I never used the technique for that type. It may or may
not help.

BTW it's just about as controversial as aerotow on CG hooks so standby
for another long thread.

Another factor may be tow plane acceleration. Tow pilots that launch
2-33s all day may not give enough accleration for standard class
gliders. I want the tug to be at full power 2-3 seconds from start of
roll.

I'll let someone else warm up the *fingers on release* topic.


Andy

Ted Wagner wrote:

A number of pilots, some by direct e-mail, pointed out that when
correcting for a dipped wing during the early part of take-off, rudder
and not aileron should be used.

I used to fly a Standard Austria off a "hot & high" airfield with a
prevailing cross wind on the narrow take off runway. The Austria was
also a bit tricky to control during the early part of the launch.

I was not the only pilot to experience some interesting take-offs from
this site. I can recall "interesting" takeoffs with Std Cirrus, Elf,
Libelle, ASW15 and ASW20's. Even the single Astir could be a handful in
certain conditions.

We learnt a number of tricks:

- Keep your hand very close to the release, and use it at the first sign
of trouble. (Pilots who aborted t/o were given special priority to get
back in the launch queue to encourage them to release too soon too
often rather than too late once too often).

- Make sure that the spectators, cars, parked gliders and other hard
and/or expensive obstacles are well clear of the side of the runway
before you launch. Particularly on the upwind side. Thats where you are
going to end up when you ground loop.

- Use less than full aleron and/or rudder while the glider is moving
slowly. If you put in too much aleron you stall the down aleron wing
that you are trying to lift and bang it is hard on the ground! The
Austria had an all flying V tail. It was possible with full elevator
input to stall the tail and loose rudder control, and vice versa.
(Note, all this while rolling down the runway below stalling speed. At
flying speed the Austria had excellent elevator and rudder control).

- I lined up the Austria pointing at an angle across the runway, away
from the cross wind. The weather cock effect would turn the glider into
wind and onto the centre line during the initial role. (Other pilots in
other ships did the same).

- Find an experienced athletic wing runner. As wing runner you should
run the downwind wing. It is natural for the wing runner to "hold back"
a little when the wind tries to weather cock the glider and swing the
wing forward out of your hand.

- Tail wheels made life easier than skids. Wheels role in their
direction of rotation and resist being pushed sideways. Skids slide in
any direction with the same amount of friction.

- However, while the tail wheel is on the ground, the rudder has very
little effect. Some pilots used full elevator to keep the tail wheel
hard on the ground during initial role and let the wheel control the
direction of travel. This did not help with the Austria - it just
stalled both the elevator and rudders see above.

- The 15m pilots used negative flaps on the initial role. This usually
worked for them.

- Some guys tried using airbrakes during the initial part of the launch.
This was said to be effective with the Elf and the LS4.

- Of course nose tow hooks helped too, but it was not always enough for
the Libelles.

- Water ballast makes it worse - but that was not an issue with the
Austria.

Some how the two seater trainers had no trouble. When I bought into a
Nimbus II, I found the launch games a thing of the past!

There was a Pilatus B4 the field but I can't remember it having
problems. Perhaps because it had a very experienced pilot and it did
not fly very often.

Have fun

Ian