This might be a little late but I've seen it mentioned several times in the old KR news letters. You don't use brakes attached to stock RR rudder pedals. You are not the first and will not be the last to find this out the hard way. The stock RR rudder pedals are not strong enough for the extra breaking force no matter how they are welded. For that matter the rudder horn is also a weak point depending on how much you had to grind away to give proper rudder travel. That is why I chose to use heel breaks. Just another reason the test period is tough. Hope you didn't break anything important. Happy landings. ----- Original Message ----- From: "Brian Kraut" <eng...@earthlink.net> To: <kr...@mylist.net> Sent: Sunday, September 07, 2003 5:44 PM Subject: KR>rudder pedals
> 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? > >
