With permission of INAV editors, below is text of short article I
submmitted to go along low ceiling F1d plan now posted our in Files
section. Just FYE (For your entertainment.)
Mark F1diddler
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This design, "Fliagra"--is supposed to stay up longer. As an
analog to patented designs, it's available over-the-counter, without
prescription. Fliagra set Cat 1 AMA record of 27:50 on 8/27/08.
(These statements have not been evaluated by the FDA.) The weights
I describe are what my brand new F1d parts weight, but by the time
they are contest or record trial-ready (meaning repairs) , there's
usually not much ballast to add, if any. Thank you to Bill Gowen for
drawing this plan.
My philosophy for low ceiling F1d flying is that the first task is to
use up all rubber turns--not easy to do with typical 9" motors and
19" props. Toward that end, I have gravitated to fatter motors (8.4
or 8.5" long, unstretched) and smaller props (17.6".) The problem
remains in how to achieve pitch change that avoids bumping a Cat 1
ceiling (mine, 22 feet) for entire flight, yet delivers the very
highest RPMs during final 6 minutes of descent. The perfect VP
spring ought to deliver such a profile, but I haven't found it yet.
Rather, after a quick (2 minute) climb almost to ceiling, a slow
descent at 38-39 RPMs, and second climb at increasing RPMs, I
usually bump the ceiling from about 14 minutes past launch through to
about 21 minutes. I assume that's where much energy is being wasted--
with unnecessary climb torque. I get a desirable high RPM (59-61)
descent for final 6-7 minutes. But if the perfect VP spring were
able to keep model off the ceiling completely, I believe it would buy
another minute or two of time. Then, goal is to do the same thing
with a bigger prop for another 1/2 or 1 minute, maybe. Springs
I've tried: 9 wraps of .009" wire, 10 of .009", 8 of .009", 8
of .008", 6 of .008" and 4 of .008". Please email me if you have a
suggestion for better VP spring. F1diddler_at_yahoo.com
Mark Bennett
Received on Tue Sep 23 2008 - 14:25:08 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:45 CET