I reckon that if the turns left are roughly equal to those backed off for a good no touch flight, the rubber thickness is well matched to the weight. After that, it's down to changing the rubber weight and matching thickness to suit.
Bob
----- Original Message -----
From: Warthodson_at_aol.com
To: frash_at_chartertn.net ; Indoor_Construction_at_yahoogroups.com
Sent: Saturday, December 06, 2008 2:52 PM
Subject: Re: [Indoor_Construction] Fwd: low ceiling high duration
Fred,
Thanks for reminding me about your files. I just downloaded them & have been entering some "imaginary" data. I haven't ever recorded "unused turns" so I will need to start recording that data before I can get any meaningful results. I think it will be interesting to experiment with different motor widths/weights & see how the results compare to the theoretical data.
Gary
In a message dated 11/27/2008 9:13:38 A.M. Central Standard Time, frash_at_chartertn.net writes:
Happy Thanksgiving, Gary and ALL,
If you go to the files section of Indoor_construction, there are two rubber motor files from me, one compiled .exe file and one spreadsheet. Both do about the same and let you enter launch and landing winder turns and rubber batch for a few batches. Then run the plot. The area between the launch vertical line and the landing vertical line is your area and it is calculated for you. You can also calculate the prop revolutions per second and the average power used during the flight. I calculate the power in milliwatts.
To answer your real question requires more knowledge than I have, but at least this can help you measure and calculate something to compare between various motors and props.
Fred Rash
---- Warthodson_at_aol.com wrote:
>
>
>
>
> ____________________________________
> From: Warthodson
> To: Indoor_Construction_at_yahoogroups.com
> Sent: 11/26/2008 9:54:31 A.M. Central Standard Time
> Subj: low ceiling high duration
>
>
> I am interested in hearing what strategies seem to work for increasing
> duration in cluttered low ceiling sites. Particularly sites where it is not
> practical to spend much time "scrubbing" because of the clutter & high likelyhood
> of getting hung up. Assume making the airplane (less rubber) lighter is not an
> option.
> Are airfoils with greater camber of any help? Would you agree that for high
> ceiling sites, cambers seem to be 3% to 5%? How about low ceilings?
> In categories with no limit on rubber weight what seems to be better:
> Low pitch props & thin rubber or higher pitches & thicker rubber, or some
> other combination? I.E. How do you optimize the "area under the curve" of the
> rubber when you are limited to a low ceiling & minimal scrubbing?
> Thanks,
> Gary
>
>
>
>
>
>
> ____________________________________
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