| Home | Articles | CP reprints |

From CP68, Page 7. July, 1991

This is a subject that has been addressed before but we continue to hear from builders who are having problems in this area. We are revisiting this problem because recently we have received two reports from builder/flyers who have had this problem on airplanes with 300 to 500 flying hours on them. These were not new airplanes. Originally the problems were associated with new airplanes doing taxi tests with wheel pants on. All the braking used while learning to drive a different airplane like an EZ, simply overheats the brake discs. This heat radiates into the strut and literally boils the epoxy out of the strut locally opposite the brake disc. Well, we are now finding out that this scenario also holds true on older airplanes. At one time, we had figured that the strut, over a period of time, gets postcured by repeated heat cycles due to braking and, thus, the heat distortion temperature goes up and makes the strut less prone to this type of problem. We still believe this to be true but only to a point. If you, for example, go to check out a new EZ pilot and have him or her conduct high speed taxi runs and stops on a runway, be certain that you will have this failure occur if you do not remove the wheel pants. There simply is not enough cooling available with wheel pants on to allow for this kind of operation. Normal take-off, go somewhere, then land operations do not put the thermal load into the discs that high speed taxi and runway flight tests do.

For additional protection from this radiating heat damage, install a 1/8" thick aluminum plate between the axle flange and the gear strut such that it extends up an inch or two above the brake disc and is somewhat wider than the strut. This will act as a heat reflector to reflect radiating heat from a red hot brake disc. You will still need to wrap the strut with Fiberfrax and aluminum foil tape to insulate the glass strut.