[NSRCA-discussion] Pull-Pull

[Dennis]

Just remember that everything you introduce into the airplane increases
weight. Weight is our enemy. While some ideas sound like they will work and
probably will, do they really need to be done? I have found that pull-pull
cables do loosen in time and may not loosen the same rate on each side of
the elevators. (right and left) I check my elevator half's for track at
least once a month. I have only found the need to realign a couple of times
and have always used pull-pull on my elevators. I always employ the K.I.S.S.
method and have the idea of weight in mind in everything I do on the
airplane.

Dennis

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Fred Huber
Sent: Wednesday, January 10, 2007 1:34 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] Pull-Pull

Someone mentioned adding a tensioner....

If the tension is high enough... no slack will get introduced.  But hinge
load could be a problem requiring a very heavy (possibly ball bearing) hinge
right at the control horn. (depending on how much tension is needed to
overcome maximum flight load)

In a way you have tensioners already... they are called grommets.  As the
servo gets loaded it can shift.  Squeeze the pull-pull cables together close
to the servo arm and watch what loading the system does.

----- Original Message -----
From: "Dave Burton" <burtona at bellsouth.net>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, January 10, 2007 10:23 AM
Subject: Re: [NSRCA-discussion] Pull-Pull


> Maybe I just don't get it, but any kind of tensioner or sliding servo is
> just going to introduce slack into the rudder or elevator system when
> under
> load. Why do you want that? Seems to me you would want the cables as rigid
> as possible. That's how I've always set them up.
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Fred Huber
> Sent: Wednesday, January 10, 2007 10:19 AM
> To: NSRCA Mailing List
> Subject: Re: [NSRCA-discussion] Pull-Pull
>
>
> Tensioner... servo mounted on sliding tray (we should al remember how to
> do
> that from doing elevons without computer mixing... CF tubes instead of the
> old nyrod on wire inherant slop should dissapear.) with a spring to pull
> the
> servo in the opposed direction to the pull-pull wires.  (simplest
> mechanicly... not sure if its the lightest)
>
> You could play with the idea...
>
> Run pull-pull back to a free pulley that is pulled by the tensioner
> spring,
> taking the side load off the servo.  Slightly more complex and adds the
> weight of the pulley, but should reduce servo wear.
>
> If you like having a bellcrank to adjust travel relationshoip between
> servo
> and pull-pull... mount the bellcrank on the sliding servo tray.
>
>
> ----- Original Message -----
> From: "Jay Marshall" <lightfoot at sc.rr.com>
> To: "'NSRCA Mailing List'" <nsrca-discussion at lists.nsrca.org>
> Sent: Wednesday, January 10, 2007 9:07 AM
> Subject: Re: [NSRCA-discussion] Pull-Pull
>
>
>> Well then, no logical reason. All, including myself, agree that it works;
>> I
>> also use it. It would also seem that if a tensioner is used, as with
>> timing
>> belts on a car, that the
>> trim-change-with-temperature-due-to-fuse-expansion
>> problem would disappear.
>>
>>
>> -----Original Message-----
>> From: nsrca-discussion-bounces at lists.nsrca.org
>> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Ron Van
>> Putte
>> Sent: Wednesday, January 10, 2007 9:15 AM
>> To: NSRCA Mailing List
>> Subject: Re: [NSRCA-discussion] Pull-Pull
>>
>>
>> On Jan 10, 2007, at 8:09 AM, Gene Maurice wrote:
>>
>>> I have been using pull-pull on elevators for 15 years with great
>>> success. It
>>> is a little more difficult to setup, but once done, it is
>>> completely idiot proof.
>>
>>
>> Gene - I'm absolutely sure someone will say, "Well, you should know",
>> but not me.  <VBG>
>>
>> Ron Van Putte
>>
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