REFLECTOR:Gear Up
John Dibble
reflector@tvbf.org
Sat, 03 Apr 2004 09:30:16 -0600
Scott B,
Why is the fork made of cast aluminum? Cast metal doesn't bend, but cracks under
stress. Wouldn't a steel fork that bends under (excessive) stress be better?
Good comments on the main gear heat issue. Rather than upgrade my matcos (stronger
brakes = more heat), I think I'll upgrade my TOL skills.
John
Scott Baker wrote:
> Fred,
> I don't think it's quite fair for anyone to criticize the factory for a
> busted nose wheel fork if it is of the old (smaller) design. The factory
> has mentioned this time after time after time in the VV that the old forks
> should be replaced. The factory subsidized the cost of the new forks. If
> someone is operating an old fork today - they are ignoring the warning from
> the factory. So please don't lay blame on the factory for an "almost
> mishap" when your older fork developed a crack.
> In regards to the main wheel getting stuck on the lip at the bottom of
> the wheel well. This was caused as you know when the main gear leg warped
> when it became overheated after being exposed to the excessively hot heat
> from the brakes. Overheated brakes and the problems that come from
> overheated brakes has also been the subject of repeated articles in the
> Velocity Views. If you ride the brakes or do repeated hard braking, a lot
> of heat develops around the brake disk, which is then transferred to the
> gear leg. Too much heat leads to a softening of the gear legs. And if
> there is any stress on the gear legs when they are soft, the legs will warp
> to relieve the stress. We need to a) understand that this situation is
> possible, b) try to avoid overheating the brakes, and c) when the brakes are
> overheated, do something about it like throwing a wet towel around the leg
> and/or pulling the aircraft forward about 15' after it has been stopped so
> that the pressures on the gear leg are neutralized, and lastly d) look for a
> warped leg during the preflight, just in case a,b,and c have been ignored.
> If the wheel or lower portion of the gear leg looks crooked, the geometry of
> the gear has obviously changed - and therefore the clearances of the gear
> going into the wheel well will be changed and there is a possibility of
> getting wheel stuck in the well. The lip at the wheel well presents a ledge
> where hardware can catch and hang-up when this happens - so yes, I agree
> with you that not having a lip is better than having a lip - but eliminating
> the lip does not eliminate the possibility of a stuck gear ... the tire
> could easily wedge itself against the wheel well and the gear could be stuck
> to the point that it might not come down. Again the root of this paragraph
> was overheated brakes and warped gear legs.