Re: Re: Thermodynamics of rubber bands

From: Bill Gowen <wdgowen_at_gmail.com>
Date: Wed, 23 Jun 2010 12:53:32 -0400

At Lakehurst last summer and at USIC this year I broke many motors (mostly 5/99) at torques about 90% of what I can wind to in my 75 degree home work area.

  ----- Original Message -----
  From: Tapio Linkosalo
  To: Indoor_Construction_at_yahoogroups.com
  Sent: Wednesday, June 23, 2010 11:04 AM
  Subject: Re: [Indoor_Construction] Re: Thermodynamics of rubber bands


    
  nick wrote:
>
>
> 'Above 40C (something over 100F) the rubber tends to get soft and break
> abruptly.'
>
> Aha - Belgrade temperature!!!

  Yup. The temperature sensitivity varies from batch to batch, and the
  best (like 1999) are most sensitive. I recall that way back then in F1B
  Eurochamps 2000 I had prepared motors of May 1999 (it was ample then!)
  for morning and fly-off -rounds, and had some motors from 1998 batch for
  the heat of the day, as that latter batch was known to stand the heat
  better. Quite needed, for in the afternoon the temperatures were above
  40C in the shade, but no shade around on the open flying field! That was
  one hot contest!

  -Tapio-


  
Received on Wed Jun 23 2010 - 09:53:39 CEST