It seems like there is a severe "two camps" division in DLG launch
technique. "Dick Barker"-style has the release at max speed with the
inside (grasping) wing almost stationary. The other camp is the
"Equal Speed"-style where the throwing hand moves forward quickly
during release in the direction of flight (no rudder pre-set needed).
I think Dick's method generates greater velocity (on the outside
panel at least), but is really a no-win trade off.
(NOTE: I don't fly DLG, but am shopping for a design so I can start.
These comments are based on observation only. IHLGF video
rewind-pause-slo-mo, Twister video rewind -pause-slo-mo, Endless Lift
rewind -pause-slo-mo, etc.)
Barker-esque analysis: The difference between the slower "inside"
wing and the outside wing has to be equaled out in order to continue
the launch without a snap-roll. The rudder preset causes drag. The
positive side is that the pilot's spinning is constant through the
launch and the launching hand is brought from behind the body,
alongside the body, and then across the front to release (pretty easy
to develop a good style).
Equal-speed analysis: There is no pre-set drag except for elevator
to tweak the release attitude. There is much less stress on the
fuselage (in the boom area at least). The speed of launch at release
is the only compromise. The launching hand comes from behind to
along side the pilot's body. At that point, the body stops rotation
(inasmuch as it contributes to a better launch speed) and the launch
hand continues on its path in the direction of launch to release.
Still, the advantage is the swinging weight and inertia gained during
the spin (and less airframe stress). The Wurts-Javelin does this
with the pre-launch run. Isolate the arm from the body (encase
yourself in cement except for your throwing arm) and both styles have
similar launch potential.
When you use the Barker-esque launch, don't you give up a good amount
of speed (energy) in straightening the flight path out...and is that
equal to the Equal-speed launch energy?
>Anyway:
> Why should the tail extend below the boom?
> Would that make it look like a + (plus) tail?
> Doesn't that dork out landings?
> Couldn't you just make the rudder twice as tall?
Theory is that the twisting load on the boom during launch is too
great. When countered by the rudder, having it centered on the boom
makes it less twisty.
Not a "+" tail, Dick Barker makes his a T-tail.
Landings aren't too bad, and most are hand-catches in competition anyhow.
Twice as tall rudders make the twisty situation worse.
- David
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