Re: Article, "Fliagra" F1d.

From: izgo <izgo_at_yahoo.com>
Date: Sat, 26 Mar 2011 00:29:21 -0000

Mark, sorry I'm bring back this old tread, but its very interesting for me, and not much else found using yahoo search feature.

I like to know about the springs, if you have managed to make a conclusion on best springs for CatI (maybe CatII too) VP tunning.

Thanks!
Ignacio-




--- In Indoor_Construction_at_yahoogroups.com, "Mark" <f1diddler@...> wrote:
>
>
> 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
>
> _____________________________________________________________________
>
> 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_...
> Mark Bennett
>
Received on Fri Mar 25 2011 - 17:29:24 CET