Re: Sanding, How Much 4 Attachments?

[Alan Shaw <wingco@iu.net>]

CBrock5000@aol.com wrote:

> Can someone tell me how far i am to sand for external attachments such as the
> elevator hinge attachment to canard.

None

The elevator hinge arms in the canard is locked down inside mechanically by way
of the large holes pre-drilled in them and the potted micro-GLASS getting under
the thick canard skin.  Even my carbon stiffened canard dramatically flexes in
turbulance so these attachments are not improved much by small thin tape glass
around the base even if bonded down to the glass under the filler.
I noticed even on my plans that the slot is 3/8" just as in the Velocity plans.
Personally I've been making this slot 1/4" or less for years but sometimes they
have to be enlarged to get the premounted elevator hinges to line up.  When a
slot gets enlarged to 1/2" or bigger then I like to sand down 1 1/2" around down
to the glass and put four or more layers of bid up to the edge of the hinge arm.

The most important "hint" is to take a 1/8" drill bit in your fingers and scrape
out 1/4" of foam out from under the edge of the slot.  When you pot the hinge
arms pack this area under the canard skin and your hinge arms will be "locked"
in.

There are three angles to align with each of these arms and the potted resin
glass mix exotherms and gets hard VERY fast.  Do your dry runs then just four at
a time then the middle last.  The arms are soft aluminum and can be bent a little
in the end to help with final line up.  If you get any that really don't line up
they will bind and should be extracted and re-potted.  Hinge arm extraction is a
whole nother book so ask me that one if you need it.

There are a lot of things I would have like to seen incorporated into the plans
and parts over the years based on my 30 years experience but Velocity is not my
company.  Yes, I do have a jig that mounts these hinge arms for the 173 and could
make them for the XL and STD.  Do you think it is worth the $400 extra I would
have to charge to make this tooling a do this step?

Alan Shaw