Re: A perfect 1/4 motor F1D flight

From: Mark F1diddler <f1diddler_at_yahoo.com>
Date: Tue, 07 Jun 2011 15:02:49 -0000

--- In Indoor_Construction_at_yahoogroups.com, "izgo" <izgo@...> wrote:
>
>
> Now Nats are over im bumping this topic. > On 1/4 tests:
>
> What you think about a 8+ minutes flight with quarter motor? I bet is good, but what if climbed too much? Instead is better a 7 minutes flight climbing 7 meters only? or 8 minutes climbing 1/3 of (a tall) site height?
>
> Any comments will be apreciated.
>
>
> Thanks. Ignacio.
>

Ignacio,
I was hoping someone would take a stab at your original question, but it was so general that the answers would have required so many "ifs," and would seem like nothing new. There are no secrets to long flights except to juggle all the little balls together that we normally address individually. A 1/4 motor flight is the most useful when you are climbing 1/4 the height of your intended site. And even then, the eventual site may have different conditions rendering the tests not as useful--for example different altitude densitites of the air. 8 minutes on a 1/4 motor sounds okay, but how high is "1/3 of a tall site?" Whatever height you reached, multiple by 4, and that is the presumed site where your test gave useful information. Since you are trimming for the Serbia hall, I recommend climbing only 5.7 meters on 1/4 motor. (But haven't flown there myself.)

How this plays out with specific RPMs per your earlier posted question is where the variables make general answers merely general, and would be concepts you probably already know. (Example, "Use up as many motor turns as possible, landing ideally at zero turns", if using VP.) I recall you once mentioned Fliagra article (in Files Section of Ind_Const.) where I mentioned the RPM profile of my low ceiling F1d. But that was merely what I ended up with that day considering my smallish prop, (17.5") the VP spring I had on that day,(I forget what,) and the motor I settled on (8.3" loop, IIRC,) to which I adjusted VP for the 23 ft scrubblable ceiling. Change any of those items, and the RPM profile would have been different. But one general RPM rule I've concluded for my style of VP F1d is I don't want to see lower than 33 at any time, nor higher than 62 at any time. Your miles may vary. HTH.
Mark F1diddler
Received on Tue Jun 07 2011 - 08:04:37 CEST