REFLECTOR: Overheated Brakes Causes Landing Gear to Bow

Wed Aug 27 11:38:56 CDT 2008

Thanks everyone for the feedback. I think that the previous owner/builder had this exact issue and had a gear leg break off much like Lou's. Looks like my path forward, clearly points to the aluminum booties.

Kirk

> From: stedmanlou at roadrunner.com
> To: reflector at tvbf.org
> Date: Wed, 27 Aug 2008 10:13:37 -0400
> Subject: Re: REFLECTOR: Overheated Brakes Causes Landing Gear to Bow
> 
> Something that you should be concerned about in this situation is epoxy 
> wicking. When the gear leg is heated up by the rotor enough to deform, the 
> epoxy is being changed back into a liquid. Gravity will then cause it to run 
> down inside the leg. After repeated heating you can leave the hot spot in 
> the leg void of epoxy and your leg will fracture at that point. That is what 
> happened to me. I have picture for anyone who wishes to see the results. The 
> bootie is the answer. It is all aluminum and replaces the portion of the leg 
> which has been damaged.
> 
> Lou Stedman
> Velocity N7044Q
> Olean, NY
> stedmanlou at adelphia.net
> ----- Original Message ----- 
> From: "Dave Philipsen" <velocity at davebiz.com>
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> Sent: Wednesday, August 27, 2008 12:25 AM
> Subject: Re: REFLECTOR: Overheated Brakes Causes Landing Gear to Bow
> 
> 
> > Kirk,
> >
> > It sounds like your warping may have been a little more pronounced than
> > mine.  Do you have heat shields?  I recently noticed one of my gear legs
> > was ever so slightly splayed outward at the bottom.  It may have been a
> > degree or two off from perpendicular.  Here's the solution that worked
> > for me.  Your mileage may vary:
> >
> > I completely removed and disassembled the wheel and brakes and axle.  I
> > then mounted the axle on the gear leg in reverse (axle pointing inward
> > toward the middle of the plane).  Then I rested the weight of the
> > airplane via the end of that axle on a wooden block (the wooden block
> > was only supporting the *end* of the axle).  The force acting upon the
> > gear leg was exactly opposite as when the wheel is mounted normally.
> > Then I used a 250-watt IR reflector heat lamp and heated the leg up at
> > about the same place where the rotor would have heated it (on the
> > outside edge of the gear leg).  The lamp was about 8-10 inches from the
> > leg.  Then, I used a ruler to measure the distance from the floor to the
> > bottom of my gear leg.  As the leg heated up and started to bend back,
> > the bottom of the gear leg would get closer and closer to the floor.  I
> > only let it go maybe 1/16 - 3/32 of an inch and then I took the heat
> > lamp off.  This procedure allowed the gear leg to bend back maybe one
> > degree or so.  After the leg cooled down I assembled the axle back on
> > the correct side of the leg, put the wheel back on (without the brake
> > caliper) and moved the airplane forward and back a few times and then I
> > checked the camber of the wheel.
> >
> > To make a long story a bit shorter, I had to do it again and let the leg
> > bend a little bit more.  Total time under the heat lamp was probably in
> > the neighborhood of 40-45 minutes. Just for good measure I wrapped that
> > area of the gear leg with some 2-inch-wide fiberglass BID tape and
> > wetted it down with epoxy.  I've probably performed 15 takeoffs and
> > landings since the gear leg "re-formation" and everything is just fine.
> > I fashioned a heat shield out of aluminum sheet metal with some glued on
> > backing made of exhaust pipe insulating cloth tape and installed it
> > while I had the axle off.
> >
> > This procedure *may* work for you if the leg is not badly disfigured and
> > if it has not been heated so badly as to cause the epoxy to actually run
> > out of the leg.
> >
> >
> >
> > Kirk Aragon wrote:
> >>
> >> Hi all,
> >>
> >> Recently, I overheated my brakes and have noticed that my gear legs
> >> have warped inward towards the rotors (in addition to small bubbling).
> >> There is currently a very small gap between the rotor and the leg on
> >> each side. I remember that someone else had this issue and
> >> Reflectorites discussed the procedures to fix this issue. Can anyone
> >> point me to that discussion as I can't seem to find it manually in the
> >> archives?
> >>
> >> Thanks
> >>
> >> Kirk
> >>
> >> N360TV
> >> SE RG
> >> TO-360-E1A6D
> >> ------------------------------------------------------------------------
> >>
> >>
> >
> > -- 
> > Dave Philipsen
> > Velocity STD-FG
> > N83DP
> >
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