Cozy MKIV - Chapter 13 (Section 5)

Rudder Pedals/Master Cylinders

Start Date: April 26, 1996

rudder pedal installation So, I finally got the rudder pedals from AeroCad (they shipped them just after getting back from Sun & Fun). I was a little disappointed - the aesthetic and dimensional quality left something to be desired (even at $150 less than the Brock pedals). Definitely usable, however - but not show quality. Anyway, I fitted the pedals as shown with the 5/8" diameter tubing. I opened up the holes in the NG-30's for the oilite bushings and then installed the pedals as per the plans with foam, nutplates, and flox.

pedals and master cylinders I bent up a couple of 1/16" aluminum tabs for the rudder pedal springs, and verified that they would NOT interfere with the master cylinders.

Using MATCO master cylinders and the AeroCad pedals, I had to improvise a bit. I made the bits and pieces for the brake actuator tubes and rods (using the AeroCad plans as a base). I floxed and glassed angle brackets to the nose floor for the cylinder mounts, and left the tubing and rods oversize so that I could adjust the pedal position later.

You can also see the brake fluid reservoir caps bolted to the top of F-5. This seemed like a convenient and accessible place to locate them. I mounted them with nutplates.

End Date: April 30, 1996

12/31/2011 Addendum:

After flying for a couple of years, I modified the rudder pedals to get the full 2.5:1 ratio from the pedal to the brake Master Cylinder by lowering the position at which the master cylinder attaches to the vertical arm of the pedal.

You can see the metal/phenolic Rube Goldberg spacer I made to lower the attach point of the brake MC.  If I was a welder, I'd have just moved the existing tabs downward. I also installed a stop, forward of the pedal vertical, (angle bracket aluminum) so that the pedal can't come forward and the brake MC cylinder can't become disconnected from the push tube.

I also increased the diameter of the torque tube that runs between each pair of pedals - there was too much "wind-up" from side to side under hard braking. I used a  tube that fits on the outside diameter of the lower pedal tube, rather than fitting inside of it. I also replaced the bolts for the torque tubes with taper pins - that removed some play in the system as well, and the rudder/brake system feels much "tighter" now, especially with metal hard lines and SS/Teflon hoses.

In the above picture, you can see the larger tubing, the taper pins and in the background, the SS/Teflon hoses from the MC's to the reservoirs mounted on F-5. You can also see bronze oilite bushings in the NG-30's for the rudder pedal tubes.


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