REFLECTOR:Gear Speed

Dave Black reflector@tvbf.org
Thu, 25 Dec 2003 16:43:20 -0500


Ronnie,

> Good note Scott B.  I wrote one along the same thoughts as
> yours and decided to trash it.  I think my gear works great
> and Velocity has a good design. 

It IS a good design. It's simple and reliable, as long as the gas strut is in
good working order. But as we have seen, the gas strut becomes weak over time,
and often does not get replaced when it should. Is this a design problem? Or
is it a maintenance problem? One could make a case either way. But one thing's
for certain: If a spring replaced the gas strut, less maintenance would be
required and overall system reliability would be increased. 

The original main gear design involved gas struts. It was a simple and elegant
design. Trouble was, owners did not always check the strength of their struts,
and occasionally a linkage went undercenter upon landing. With the main gear,
the hydraulics have no ability to hold the gear down (it's all done by the
overcenter linkage). So there were a number of "collapsed upon landing"
accidents. Eventually the overcenter mechanism was redesigned and the gas
struts were replaced with springs. 

Obviously the nose gear is not as critical as the main gear. Plus, as long as
the hydraulics are working, they help hold the nose gear down even if the
overcenter comes unlocked. But nose gear problems are preventable. All we need
to do is ensure our side guides allow NO place for the gear to become stuck,
make certain the gear drops smoothly by gravity, and check regularly that the
gas strut is powerful enough to force the linkage overcenter WITH AUTHORITY. 

Because this last item has bitten the Velocity community so many times, I vote
for either replacing the gas strut with a spring or at least assisting it with
one. This should be a simple mod rather than a redesign.

Dave Black
Shortwing RG