Re: 2017 SS rubber [1 Attachment]
So cross.up, am I correct that your motors are breaking at 70 wonder turns on a 15:1 winder? That is very odd, as 70 turns on a 15:1 winder is only 1050 turns in the motor. An A6 motor should be able to take many, many more turns (which is probably why you are frustrated). Try this. Forget the spreadsheet for a moment, and make a short loop of your intended A6 motor. Wind that loop until it breaks. Record the torque before the rubber broke, and the number of turns to reach that torque. Use those values to get an estimate of turns per inch that your actual motor can accept.
When you go to wind a motor for your next flight, stretch the motor out to 5-6x length (or more....I don’t know if it’s right or not, but I stretch my motors until they are pretty tight, then come in a few inches) and wind in half of your anticipated turns. So if you are shooting for 200 winder turns (3000 turns on the motor), put in 100 winder turns while stretched. Slowly come in as you put in the remaining turns. Pay attention to the feel on your winder handle. The turning action will get noticeably firmer as you approach max torque/turns. Once I start feeling the handle firm up, I will stop winding and use my free hand to feel the rubber. If it feels really tight, I will come in more to decrease tension. If, after coming in a bit more, the rubber is still really tight, You could try adding more turns carefully, or call it good and load on the model or back off to launch torque, if needed.
Give that a try and see if you don’t get a better wind.
Sent from my iPhone
> On Apr 27, 2018, at 6:09 PM, Don Slusarczyk don_at_slusarczyk.com [Indoor_Construction] <Indoor_Construction_at_yahoogroups.com> wrote:
>
> [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 * <dpgbkpgdnccnbibl.png>
>
> 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 [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.
>>
>
> --
> Don Slusarczyk
>
Received on Sat Apr 28 2018 - 00:35:33 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:49 CET