|
Incident report:
We have several reports on the Lazier of the bolts
holding the prop on the
hub shearing off. Laboratory testing showed that these bolts are the proper bolts but that
they had failed from bending, following progressive fatigue. The bolts had been installed
approximately 1 hour prior to failure, and had been torqued to the proper requirements.
In 1984 Ultraflight Sales Ltd. issued an alert warning of the possible vibration
problems associated with using non standard propellers on their craft.
We also have reports of prop bolt failure on 64 inch props, when used on the Beaver,
Maxair and Chinook aircraft.
Suggestions:
Sorry folks your on your own on this one, as far as the Lazair goes.
A solution that
has worked for the other aircraft mentioned above is the use of the GSC systems ground
adjustable propeller. This propeller uses an aluminum hub with 6 bolts, plus 6 dowel pins,
which screw into the Rotax reduction drive, flange and fit into blind holes in the back of
the propeller hub. These dowel pins relieve the bolts of any stress.
For
more information on the Lazair click here.
Lazair
Pilots forum |
