While installing the original Europa Rotax 912 engine mount I noted that the
mount contacts the high strength bolts on the radius between the head and
shaft rather than bearing on the underside of the head. I bought stainless
washers and chamfered the inner diameter on one side to allow contact with the
underside of the bolt head, using one washer on each mounting bolt. In a
classic case of cart before the horse, I then looked at AC43.13 and found that
they recommend using a high strength washer rather than a standard washer.
These bolts seem to be in shear rather than tension, so is use of a standard
washer allowed in this application? Or, should I chamfer the tubing through
which the bolt passes on the mounting frame to allow the bolt to seat
properly?
In the same area, I've looked through the Europa manual and the Rotax supplied
manuals a couple of times and can't seem to find the torque specification for
these high strength mounting bolts. Could someone point me to the specs in the
manual or supply same?
Regards, John A044
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