May I ask the following via the forum, because I don't want to add to
Andy Draper's bulging electronic in-tray or list of telephone calls...
I've just had a look at the Mod 70 description (Thank you, Steve D) and
wondered whether any of you have discussed, with Andy or PFA
Engineering, the possibility of fatigue of the new unrestrained mass
balance arm.?
The new design, without the bracing cables, looks a recipe for a fatigue
failure at or near to the TP18B fitting. (From vibration in the
horizontal plane).
It would make for some peace of mind to know that a fatigue analysis or
tests have been conducted to demonstrate that the thicker wall tubing of
the arm will be sufficient, in itself, not to suffer fatigue as it
oscillates between the rubbing strips.
Why didn't the new design retain the cables? It is a minor weight
penalty, would its retention be overkill/over-engineering.?
Regards,
Dave Moore
Monowheel 550
Aberdeen UK
|