REFLECTOR: Roll trim mod suggestions

[Epstein Lawrence Jay]

I am concerned that this type of modification adds a failure mode which could be deadly.
The factory trim may not seem elegant, but it works. With the Factory system, there is no way to have a "runaway trim" (it could happen, but you can easily override it).
Runaway trim on your system could be catastrophic.

My $0.02.

Larry Epstein


On Dec 11, 2013, at 1:42 AM, Brooke Wolf <bwolf1 at tds.net> wrote:

> Don
> 
> I have the factory setup on mine and it is not a problem.  The string and pulley system may seem a little cheesy but, surprisingly,  it works.  I too was concerned about its utility.  On the ground, without air loads, it seemed to slip quite a bit.  The only thing I did different during the build was to coat the string with  a little belt dressing.  It still slipped (on the ground).  I haven’t touched it since.  It works just fine in the air.  Frankly, since beginning flight, I haven’t given it much thought.  It is just not an issue.  I trim subconsciously in both roll and vertical modes with the standard “coolie hat” switch.  Somehow without thinking about it, the airplane stays trimmed in both modes.  
> 
> BTW,  the check is in the mail.  Thanks
> 
> Brooke
> 
>  
>> 
>>   1.  Roll trim mod suggestions (Don Johnston)
>> 
>> From: Don Johnston <numa at comcast.net>
>> Subject: REFLECTOR: Roll trim mod suggestions
>> Date: December 10, 2013 at 9:51:58 PM EST
>> To: "reflector at tvbf.org" <reflector at tvbf.org>
>> Reply-To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>> 
>> 
>> Requesting suggestions from the hive mind...
>> 
>> After hearing all the comments about the stock roll trim slipping, I decided that I would go another way. When I saw Geoff's solution, I felt it was perfect. 
>> 
>> Except he has a motor with a .25" shaft where mine is 5/16". The pulleys for the 5/16" shafts are only available in a larger diameter and that caused interference issues with the aileron torque-tube bellcrank and cables. 
>> 
>> So I decided to go with a system similar to what is in my Cessna. Chains!  Absolutely no slipping with chains. And it works great. Positive motion and no slipping. In fact, it will pull the spring around the pulley. Which causes it to derail and get caught in the bellcrank. :-(
>> 
>> I'm wondering if anyone has any suggestions on how to put in a (simple) motion limiting mechanism. It would have to be on the motor or chain. My first thought was microswitches that reverse the motor direction. But I cant' figure out how to trigger the switches. 
>> 
>> Don
>> 
> 
> _______________________________________________
> To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
> 
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20131211/daffea17/attachment-0001.html>