Tail Wheels & Tail Booms snapp'n

Hmmm,
I have repaired maybe 15 broken booms including 3 that I have cardinal
knowledge of and it is my humble opinion that the tail wheel dragging
sideways has little to do with snapping the boom. In all 3 of my
personal recollections, the tail was off the ground during the event
(2 had wheels, 1 had a skid). I watched a Discus come as close as it
could to breaking its boom when it landed beside me, only a bit deeper
into the barley field at Camby, Ca The left wing tip caught a clump of
barley and around it came, tail off the ground, spun 180, T-tail laid
over a good 30 degrees, then the boom came down and she just sat there
and shook for a moment. What determines weather you break the boom or
not is speed, ground loop below 40 knots and you will probably come
out unscathed, do it above 40 and she's likely to break (Libells
reduce by 10 knots). What's really going on is simply this, The wing
can take it quite well because it has a spar, the boom doesn't and
one side goes into compression while the other is held in tension,
compression looses and buckles inward, do it hard enough (speed) and
she snaps off, tail wheel had very little to do with it.
As always, just my humble opinion,
JJ

JJ,
If I may add.... The torsional load of the T tail, especially with
lead weight installed is a big factor as well. I do not believe the
style of tail wheel is a factor in tail boom fractures.
The style of landing, on the other hand...

Rex

Guys - Tail up prevents catching on rough ground
and reduces side-load on tailboom if in crops.
Tail up if you start to groundloop !
See ya, Dave

On Nov 20, 5:32*pm, Dave Nadler wrote:
Guys - Tail up prevents catching on rough ground
and reduces side-load on tailboom if in crops.
Tail up if you start to groundloop !
See ya, Dave

I have to disagree here as far as suggesting some technique thet is
planned.
Tail up almost ensures a ground loop.
Tail down reduces the likelyhood of a groundloop substantially.
Very few ground loops occur as a planned event(the "I'm running out of
field" event). The strong majority are surprises caused by catch a
wing.
I most cases, the lower energy in the event that come from a slow held
off landing significantly reduces the likelyhood of a fuselage
breaking event.
If you lose it, you don't have much time to try to raise the tail.
Just squeeze the brake hard and hope for the best.
Another opinion FWIW.
UH

Sorry if I wasn't clear:
Tail up AFTER ground-loop starts or is inevitable,
not first. There's plenty of time to respond.
This is *after* a fully held off tail-first landing.
Seen it done multiple times ;-)
Do wish I had a video of the 22 going around.

PS: Most of these guys have Tost brakes so
squeezing won't do anything...

On Nov 21, 6:14*pm, Dave Nadler wrote:
Sorry if I wasn't clear:
Tail up AFTER ground-loop starts or is inevitable,
not first. There's plenty of time to respond.
This is *after* a fully held off tail-first landing.
Seen it done multiple times ;-)
Do wish I had a video of the 22 going around.

PS: Most of these guys have Tost brakes so
squeezing won't do anything...

The most important reason for forward stick in a ground loop is not to
save the tail boom, as it will come crashing down at the termination
of the event anyway. Keeping the nose buried helps prevent an inverted
wingover as the wing accelerating forward develops enough lift to turn
the ship upside down. This can be fatal and almost was to Joe Conn at
Chester, SC in his ASW-17 many years ago.

And, further to the subject, all pilots should know how to execute an
intentional ground loop should they be faced with the need (fence,
road, embankment, etc.) Stick full forward, wing down, full rudder in
direction of down wing. This is part of German gliding instruction.
Should be here as well.