Good info Tapio, I think that the flight times in Slanic agree with your values. I did tests on 5-99 in preparation for the 2002 WC at Slanic and got similar drops in power between my normal testing temperature of 20 to 22 deg C and testing at 10 deg C. I did this both in my back yard ( in the shade) at 10 deg and in Mark Schaefer's cave in Dayton at around 50 deg F. What was strange was the turns and maximum torque were not that different but the foot pounds per pound value was down. I did not run enough tests to create the kind of data that Garry would like to have but the results were definitely there. I always wanted to do the same tests at 30 deg C but never got around to it, and the only rubber I used was 5-99 as it is all I use in competitions.
By the way Tapio, how is your F1M flying these days and did you get your VPs working?
To those of you who haven't met him, Tapio attended USIC and West Badin with us a few years back while he was living in Canada working on his PHD degree. We did some serious F1M flying at both meets.
Fred Tellier
----- Original Message -----
From: Tapio Linkosalo
To: Indoor_Construction_at_yahoogroups.com
Sent: Monday, February 26, 2007 6:10 AM
Subject: Re: [Indoor_Construction] Flight Temperature
On Mon, 26 Feb 2007 dgbj_at_aol.com wrote:
> This temperature difference would make a 4 or 5 percent difference in energy
> (about 0.3% per Fahrenheit degree). The energy relations for rubber must be
> calculated on an absolute temperature scale. There is not a 15% energy
> difference between the temperatures you mentioned.
Wrong. The figures that I quoted were normalized from the slope parameter
of the regression model fitted to measured data (also other data points
than 15C and 30C). For a regression model it makes no difference where the
zero point of the temperature scale lies, any interval scale on X-axis
(the independent variable) will do. The 10% difference in energy return
between 15C and 30C is a correct value, and is actually observed in the
measured data, not just derived from the regression model. It may be
questioned, however, for what temperature range the reduction of the
energy return remains linear. Definately this will NOT apply down to
absolute zero, and also the increase in energy return will saturate
somewhere between 30 and 40C, above which the rubber will get too soft to
store the energy.
-Tapio-
[Non-text portions of this message have been removed]
Received on Mon Feb 26 2007 - 09:41:17 CET
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:44 CET