I was doing some high speed taxi testing today and almost took out the lights at the end of the runway when my left rudder pedal snapped off. My pedals are .035" wall 5/8" steel tube per the plans. They are made of pieces cut at a 45 degree angle and welded instead of being bent like some are. A weld with hardly any penetration that was also ground smooth by the original builder broke right by the pedal. The extra stress of the hydraulic brake and pedal brought out a problem that never surfaced before it had brakes on the pedal. Are other people using the same size tubing with brakes on the pedals?
I will add half sections of 3/4" tubing over all the joints and reweld everything to keep it from happening again. I also plan on shortening the arms that go to the master cylinders to give me more leverage with less pedal pressure. Can anyone with effective brakes that don't require a lot of pressure tell me what distance your master cylinder attaches from the fulcrum point of the pedal? You can see my current arrangement at http://www.engalt.com/flight1.htm in the first picture. The attach point of the master cylinder end is 1 3/8" above the center of the rotating point on the pedal and about 1 5/8" back. The straight line distance is about 2 1/4" from the rotation point of the pedal to the master cylinder clevis end point. I think I need to shorten that to closer to 1 1/2" to have effective braking without overloading the pedals or the rudder horn. Comments?
