Re: 10/97 and 7/99 tan II rubber

From: Yuan Kang Lee <ykleetx_at_gmail.com>
Date: Fri, 17 Jun 2011 02:21:56 -0000

Many of you offered your experience with 10/97 and 7/99, and your comments were much appreciated.

I have used 7/99 extensively for my EZBs. Based on flight times, I think it is pretty good. I am not a diligent rubber tester, so I have not compared the 7/99 closely with other batches.

I have found that it can be wound to high turns at high torque -- whether it unwinds with high torque compared to other batches, I don't know. I have found that most 7/99 motors are good and can be wound hard at least a few times.

I have from time to time substituted 2/99, 10/97, 4/10, 7/10, 3/02. Each time, I have found the 7/99 to be better. But these are not controlled comparisons, and other factors may be in place: motors may not have been well broken in, motors were of of smaller cross section.

I will try 10/97 for low ceiling flying in the future. As others have said, 10/97 is "torqy" but does not give enough turns.

At USIC 2011, I also used 7/99 for LPP. These motors are roughly .085", compared to .030" for my EZB. I found these thicker motors to be very brittle. Of the 6 LPP motors I made, 4 had severe cuts on them after one hard wind. Of the 2 remaining, I could get 2 hard winds on each before breaking.

It appears to me that a thick 7/99 motor (.085") is much more brittle than a thin 7/99 motor (.030"). Can anyone think why this is the case? I won't be using the 7/99 for LPP anymore.


Regards,
-Kang


--- In Indoor_Construction_at_yahoogroups.com, "ykleetx" <ykleetx@...> wrote:
>
> Thanks, Max, Bob, Aki, Steve for your feedback.
>
> Seems like there is very little knowledge of 7/99, except from Bob, and that it is excellent!
>
> Seems like the feedback on 10/97 is also very good and held a Cat II F1L record. Not as good as 5/99 (of course not) but lots of torque perhaps not enough turns.
>
> I'll be doing some tests on EZB motors that are around .024" x .4g and compare these batches to the 3/02 I have.
>
> -K
>
> --- In Indoor_Construction_at_yahoogroups.com, "ykleetx" <ykleetx@> wrote:
> >
> > What does everyone think of these two vintages? I would love to hear your experience, opinion, advice. Rumors are okay, too. I recently bought some and now would like to test and use it. Thank you.
> >
> > -K
> >
>
Received on Thu Jun 16 2011 - 19:21:59 CEST