Spectra isn't a very good launcing line Dave.
There is no give in it, and lots of planes would pop off.
There is no energy that can be gained from it.
Limit the power and put mono on. No more power problems.
Just $$ problems.
David Klein wrote:
You guys really aren't looking at the international trends that are
driving the size wars. These planes are designed as the ultimate F3J
plane. In F3J, the launch power is as much as you can use, figuring
you higher some offensive lineman to tow. If F3J were to switch to
using F3b winches, the launch power is regulated. F3b has evolved to
smaller planes, that launch higher in a no wind, or downwind launch
situation. If F3J planes were to go to a regulated launching system,
the planes would get smaller, in order to launch higher faster in weak
launch conditions.
So the planes will continue to grow as long as there are large towers
with a lot of power to launch them. Bigger planes are more efficient,
so If you can launch them, you are at an advantage. Planes will grow
unless we regulate launching power.
BTW
We don't have a winch power problem we have a winch line problem. We
use crappy/heavy braided line rather than high performance Mono
filament spectra. The mono is temperamental, so I don't recommend
switching out club winch lines, but just understand the problem.
If F3J switches to F3b style regulated winches, the planes will come
back down in size, or at least stop growing.
On Dec 20, 2007 9:32 AM, tony estep < [EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
----- Original Message ----
From: Darwin N. Barrie < [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>>
...My concern is the launching equipment. With the current crop of
moldies, line breaks and winch bogging and ultimate failure are
becoming more prevelant....
======================
I wonder about this too. The Pike Perfect is the current WC plane
and the current Nats champ, at a bit over 140", and has apparently
set a new benchmark that eclipses the 132" planes, which in turn
pushed out the 3-meter (118") planes. It's all too easy to break
the line with a PP, and line breaks will presumably be even more
likely with 150" planes that have larger wing areas and can
generate more pull.
The 2-man tow setup puts a practical limit on F3J, but apparently
that limit is not fully compatible with the standard U.S. winch
setup; that is, it seems that the F3J scheme can launch bigger
planes than our typical winches like to handle. One imagines a
nightmare scenario where the planes keep getting bigger, and
eventually as clubs need to replace their launch gear, they'll
turn to super-power Injoy or similar winches, and the cycle will
repeat, and finally we'll be flying models 40% of full-scale like
the gas-power boys.
--
David Klein
Graduate Research Student
Department of Structural Engineering
Jacobs School of Engineering
University of California San Diego
--
Jeff Steifel
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