Ball Links

Has anyone used the large Rocket City ball links for the pushrod to horn connections in a stunter? These links use a 1/4" dia ball and 4-40 threaded connection to the pushrod.

I'm currently building a 650 sq. in. size plane and thought these ball links might prove quite useful. I read a short article in 'Stunt News' a year or two ago on the positive use of these, but I've seen nothing since.

Any experience?

Thanks,

Fred Krueger

Fred,
I used Rocket City ball links on my 2 RD-1's. I also used them on my Bucaneer 740. They work great. I use the 4-40 on the bellcrank to flap horn and then used the 3/16 4-40 on the flap to elevator horn. I used the smaller size because of the cramped quarters by the elevator horn. I also used a carbon fiber pushrod with grade 8 4-40 screws JB Welded into the pushrod. Then I used aluminum tubing glued to the outside to prevent splitting near the ends. It worked great and is very smooth.

Fred:

Noel "we have the technology" Drindak has thouroughly tested these critters and says that they work. Take his stuff to the bank!

Central Hobbies sells nifty titanium (or stainless) ends for carbon rods that just work super with the Rocket City links.

Hall's Hobby, of Steve Moon fame, in Texas, has all of the stuff, and are in the latest Stunt News!

See Ya

The current Stunt News has Noel talking about the new bird he is building and he is using the Central Hobbies/Rocket City combination. After the test program he ran on this gear, if he uses it himself, it's good enough for me.

>I used aluminum tubing glued
>to the outside to prevent
>splitting near the ends.
>It worked great and is
>very smooth.
>
>Crist

I wrapped the outside with a few turns of kevlar thread and put a drop of CA glue.
Have another question: is any kind of lubricant necessary ? I am currently using silicone grease, but some people said it just helps collect dirt and doesn't help anything.

jmh

>>I used aluminum tubing glued
>>to the outside to prevent
>>splitting near the ends.
>>It worked great and is
>>very smooth.
>>
>>Crist
>
>I wrapped the outside with a
>few turns of kevlar thread
>and put a drop of
>CA glue.
>Have another question: is any kind
>of lubricant necessary ? I
>am currently using silicone grease,
>but some people said it
>just helps collect dirt and
>doesn't help anything.
>
>jmh

JMH,
I've used ball links on my R/C helis for years and we NEVER use ANY lube on them. Keep them dry. On my C/L planes I installed them dry.
Crist

>Have another question: is any kind
>of lubricant necessary ? I
>am currently using silicone grease,
>but some people said it
>just helps collect dirt and
>doesn't help anything.

No lube is necessary. I would guess that most petroleum-based oils/greases would not be comaptible, long-term, with the plastic.

>Has anyone used the large Rocket
>City ball links for the
>pushrod to horn connections in
>a stunter? These links
>use a 1/4" dia ball
>and 4-40 threaded connection to
>the pushrod.
>
>I'm currently building a 650 sq.
>in. size plane and thought
>these ball links might prove
>quite useful. I read
>a short article in 'Stunt
>News' a year or two
>ago on the positive use
>of these, but I've seen
>nothing since.

This is the only thing I use, they work absolutely fine, and last apparently forever. The only caution I would recommend is to make sure that you don't bottom out the threaded part in the link. This will cause a weakness at the base of the link. Aside from that, no problems at all, even after thousands of flights.

Central Hobby told me that they have dropped the stainless pushrod ends, but still sell the titanium ones. Their CF rods and the ends are expensive, but worth every nickel, I think. The small diameter ones are way smaller than Dave Brown rods or arrow shafts and stiffer. Combine with the ball links and you have a terrific setup. I'm going to them for everything I do, RC and CL. One other thing I may try is the ball-link control horns from Robart. I have used these on RC ships and love them. The only trouble is that they aren't adjustable.