I'm not sure about rubber weight and theoretical duration but at the PPCC last weekend (37' smooth ceiling) I was flying 1.22 grams of rubber in F1L, 1.10 in A6 and 2.25 in LPP. This resulted in 2 firsts, one second and a site record in A6. I also fly about the same weight rubber at Kent (max Cat 2), in our local Cat 1 sites and at USIC (116' Cat 4). I've done a good bit of talking over the last few years both privately and publicly about these numbers. Not many people seem to think they are valid which actually suits me just fine.
----- Original Message -----
From: Don DeLoach
To: Indoor_Construction_at_yahoogroups.com
Sent: Saturday, March 06, 2010 5:57 PM
Subject: RE: [Indoor_Construction] Re: Optimum Rubber
Great synopsis by Don S. That last 25-30% of rubber weight contributes almost nothing to theoretical duration.
Don D
------------------------------------------------------------------------------
From: Indoor_Construction_at_yahoogroups.com [mailto:Indoor_Construction_at_yahoogroups.com] On Behalf Of Don Slusarczyk
Sent: Saturday, March 06, 2010 9:45 AM
To: Indoor_Construction_at_yahoogroups.com
Subject: Re: [Indoor_Construction] Re: Optimum Rubber
2:1 works out mathematically but if you graph the relationship out you
will find that above ~1.4 to 1.5 to 1 the difference is off only by
about 2% of the theoretical maximum of the 2:1 ratio. Coincidentally
if you look at many 65cm rule F1Ds you find the rubber weight used then
was in the 1.4-1.5 gram range. Going above 1.5 to 1 generally is not
possible as the strength of the model can not handle a fully wound motor
of such weight. Imagine a 2.4 gram motor on a 1.2 gram F1D wound to
capacity. However some events do not follow this rule at all, LPP and
F1L are the first two which come to mind. LPP likes below 1:1 which may
be a result of the 12" prop limitation and 10" motor stick limitation.
F1L seems to like 1:1 possibly due to the motorsticks being somewhat
limited in length due to structural reasons. So it is not a steady rule
for all events.
Don
Received on Sat Mar 06 2010 - 22:38:43 CET
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