Don,
Can you tell me where your turns formula came from? I am interested because in 1995 I worked out a formula by theory (no actual rubber winding tests) but it gave good results. It took into account things like rubber density and maximum stretch. A year or so later I took some of the variables that were near enough constants and assumed that lengths would be in inches and weights in grams and used just one constant (which was near enough 44) for general use. This made my formula: 44 sq.root( L^3/w), where L is the length of the motor and w is the weight of the rubber. As you can see, my formula is the same as yours so I am puzzled that someone else would have used the same sort of reasoning that I did.
John Barker – England
From: Indoor_Construction_at_yahoogroups.com [mailto:Indoor_Construction_at_yahoogroups.com]
Sent: 27 April 2018 23:10
To: Indoor_Construction_at_yahoogroups.com
Subject: Re: [Indoor_Construction] 2017 SS rubber [1 Attachment]
[Attachment(s) from Don Slusarczyk included below]
For TSS I use this formula for max turns of a "broken in" motor.
break turns = 44.2 * Loop length *
loop length in inches = the initial loop length when tied not the length after broken in.
TSS has about a 8-10% less stretch ratio so loops will tend to need to be 8-10% longer to get equal turns.
Don S
On 4/27/2018 5:07 PM, cross.up_at_verizon.net <mailto:cross.up_at_verizon.net> [Indoor_Construction] wrote:
After the comments on the 5/99 batch "program", I'm hoping you guys can shine some light on what I'm experiencing.
After seeing the Hodson Wart A6 record was set with some 3900 turns I realize I need to wind more and better if I'm going to get to and past 6 minutes. When I first my first A6, a Stevens design I was given some "good" rubber by the guy stripping my FAI modeling purchased(in 2017) rubber. Because of many constraints including a 20' ceiling I spent more time trimming that try to pack on winds. Fast forward to this year and a 45' huge venue and I am needing a LOT more turns.
So I find and load up Bill's 2010 data in Frash's spreadsheet and see I should be putting in 230 winder turns for my weight and lenght of rubber. Lubed with FAI lube, ArmourAll or Bill's fav, synthetic shock oil, I get the recommended max torque at 20 winder(15:1) turns and by coming in to the stooge and winding slowly I can get to 70 winder turns then BLAMMO!.
I've tried and tried to no avail to do better. I have worked the rubber by working up slowly from 30 winds over 10 sessions, I've tried low initial stretch, Bills recommended 5-6 length initial stretch and nothing seems to make enough difference to matter. I get rubber batches vary and 2010 might have been a good year but shouldnt I expect more than 30%. The kicker is the last of the "good" rubber had no issue going to 100 winder turns and I have no idea how much more it could take.
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Don Slusarczyk
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Received on Sat Apr 28 2018 - 12:25:30 CEST