The only thing I can guess is some kind of frictional condition where you have some rivets sheared off between the torque tube and the airfoil of the flaperon. It bites on the ground and then when you are in the air it just starts to slip under flying load conditions....
http://www.avidfoxflyers.com/index.php?/topic/530-go-kart-to-matco-brakes/&page=1 Hey Vance: I would suggest you read this thread to assist you in understanding what can be done and what to expect regarding the brakes you have and how they can be made to work within the limits/understandings of the physics that have been achieved.
I'll add this... I run my matco tail wheel with compression springs as I think most people are doing. and like the above video run them loose enough to keep any binding from interfering with the unlocking mechanism. I am also running with a light tension spring in the mix. running it inside the compression spring to keep the unlocking mechanism under a constant spring tension that will ensure the wheel stays locked until I want it unlocked. This is not something matco specifies but after reading in their literature that the mechanism is designed to release with light spring tension.... as well as addressing the reality that without constant spring tension it can come unlocked.... the obvious answer is to do the dual spring setup to accommodate the mechanism...On my last tail spring setup I got the compression springs for steering the tail wheel too tight and it won't release without some added horsing
Depending on how fussy you are about the appearance of the welds inside you could get a piece of non conductive carbon rod to fit perfectly inside of the pipe shell you are welding on and control exposure to oxygen and give any melt thru essentially no place to go. Coming up with a place to get a piece of carbon rod to fit exactly inside and completely compliment the radius will be a perhaps bigger challenge than it is worth.
I concur with Joey"s sentiment.. Don't fly this plane until you get a full understanding of what is creating this anomaly and rectify it. I would suspect some sort of in congruent deployment of the flaps when the flaps are in full position deployment. What is causing it if it is the problem I couldn't tell you.... At a keyboard it is just all speculation.
If it has what is described as a round kitfox type cowl, what you are probably looking at is that aftermarket cowl that Lee Dubay developed for the avids. Avid did offer it with their kits as an option for a while. Called it the Avid Avenger package.
One thing you could try is to get an after market windshield washer setup and install it into your plane and use it to spray water on the rads as required to control heating. i do have on installed on my model c with internal rad and use it from time to time on hot days in climb out.
In terms of desquirrelifying my own avid, I did these things. On my matco tail wheel I run compresson springs a bit loose with weight on the tail as well as then having a light thin tension spring run up the center of the compression spring to keep the steering arms under constant tension so the tail wheel can't come unlocked inadvertently. Pivot bolt geometry of the tail wheel can/will have an impact on the handling of the aircraft on landing and deceleration. Positive caster steers easier but is typically more squirrely than neutral or negative caster. Ran positive caster for a long time on my plane and because of it learned to land/ taxi using brakes only for directional control. For me the best rule of thumb became to use the brakes to steer the plane in a straight line, use the steerable tail wheel only when you need to turn the aircraft. The most important thing I did was rework the toe brakes on my plane so I could be confident I had full effective control in taxi and landing. Joey's thread Gocart to matco brakes covers that change up.
Well I suppose there is a formula for determining optimum ratio for piston sizes in a hydraulic brake setup but I don't know what that is. Multiple caliper or caliper piston setups would preclude the use of larger mc pistons so as to mitigate excessive piston travel to get fluid activating the caliper pistons. Final success is about building a leverage structure that can successfully turn leverage into line psi...not only on paper but on the plane itself.
Hey Joey. Ya still kickin. Interesting to hear about the intensifier experiment with your plane and how it worked out. With the avid rudder bar brake pedal design a smaller piston in the mc should lead to more pedal travel and less mechanical leverage. But I think the crude math i did a long time ago showed the intensifier would help like 10 percent with the avid setup on paper with the single w62 caliper on the hydraulics improvement end of things squared off against the mechanical loss.