"Buck style" bellcrank failed after 300 flights

[Serge_Krauss]

Several years ago I ordered two of these from Tom. They arrived compromised in adhesion and were not centered. I sent them back and received two new ones that were slightly better. I won't use them. I like Brett's, as shown in forum pictures, and do not think that the outside manufactured ones measure up in quality. I hated to write this, but the defects were noticeable. - SK

[Air Ministry .]

Comisrations,
Theres a chance id be somewhat put out , were it me .

I relate Stunt Ships , if ' All Weather " planes , to say rally cars , or moto-X / Enduro motosickles . Somewhat bounced around and ' stressed ' .

Therefore ' Service Life ' , is related to durability . Envisage a FoMoCo like test cycle device , operating it thousands or millions of cycles . 

" I still wonder if this isn't an artifact of the crash.  Chris, was this indeed the "up" line?  Coming downhill in the hourglass, the controls are neutral, pulling from a neutral position, so we are saying that the "Netzeband wall" (hinge moment) is what did this? We're talking about a 12 to 15 lb. pull, 20 at most. I'm not convinced that this was the failure.  "

Flying in knew zeelund , whilst the Americas cup twits were chickening out , as their boats blow up if theres a chop & thirty knot winds ,

the two kilo Spitfire , G 51 , on a grass circle / center - would have you dragged on Std Shoes , downwind . If it was damp . As it sometimes is when it rains .
Thered be a pull of at least 50 POUNDS .
Golf Shoes ( studded ) Kicking ones heels into the ground , leaning back . Often both hands on handle .Twanging a line in Sq bottoms on .018 7 strand steel .

Therefore if we do a 200 % operating load multi cycle test , And a destruction - cycling - test . We'd see how it ' GOES ' . 

[PJ Rowland]

I know this is a slightly older thread, but one thing bothers me about it..

300 flights is a very short time for failure, and I noticed Chris said

"  I put a lot of flights on planes and it lasted for 300. My guess is that most people who use the crank don't fly that much. "

Well Ive used the Tom Morris / Brett Buck bellcrank on all my models since 1998, when I would purchase them off windy.
I never had one single failure, and flew this same bellcrank system on the Lancaster, which weighed 120oz.

On my regular competition ships I have had no problems with the bellcrank ever wearing out.
Now I as for total flights,  I have my own circle and can fly as long as I like. 300 flights? Id do that in a week, no problems.

Im not going to comment on the failure beyond saying Ive installed the same purchased product for 20+ years, and have certainly pushed "number of flight" envelope beyond 3000 flights on more than 2 plan.

The last major failure of a control system I had was breaking a titanium 4.40 bolt. Due to a faulty manufacturing process.. so that CAN happen..

This is Bretts point, its hard to associate your name if you dont have 100% control over the finished product.
I personally started using the bellcrank because it was endorsed by a World class engineer and pilot, so yes I believe the products I have purchased and use have been nothing short of "exceptional" and a 100% success rate.

[Ken Culbertson]

I have my own circle and can fly as long as I like. 300 flights? Id do that in a week, no problems.