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Old March 30th 09, 06:22 PM posted to rec.aviation.homebuilt
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Default Metal vs Wood or T2 vs VP (Part II)

On Mar 29, 7:04*pm, Bob Hoover wrote:

Homebuilders could turn out some damn good airplanes on the cheap if
we can come up with a mini-production line for vacuum bagging leading-
edge sections for a couple of standard airfoils, such as 4412, 4415 or
the M6, in lengths of about 48 inches. *Properly done, the section
gets peel-ply'd on the interior and the edges get stepped. *It locks
you into a rectangular plan-form but you can come up with a good D-
cell, allowing you to produce a really good wing.


I've had similar thoughts and have done some small experiments with
the TPG process. Haven't yet found the right core material. High
density PVC foam looks promising in place of Taylors paper. I have
some to play with but started projects must be completed first.

As for being "locked" into a rectangular plan-form, I'm not so sure.
There seems to be enough flexibility in the formed leading edges to
squish them down a bit after cure. The leading edge radius stays
larger then a full scaling down but that might work out to be an
advantage when it comes to tip stall?

While I'm thinking about it - vacuum sources. Mine is a water bed
drain tool. Works great and cost little. Set it up on the lid of a
Rubbermaid type tub of water with a small recirculating pump and you
have an inexpensive and reliable source of vacuum. When your finished
everything stores in the tub for the next use. Just remember to put a
check valve on the outlet or you risk sucking in water if the power or
pumps prime gets interrupted. A good source of check valves ... power
brake hose from about any salvage auto. For vacuum control a fish
tank air valve works well enough.
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Leon McAtee