> http://www.visionaircraft.com/
    >
    > This is a fantastic idea. Steve Rahm is a genius.
    >
    > Solid composite in the curves and sandwich in the flat sections
    > where you need it. Spray on gel coat. Lay up on glass so there is no
   need for
    > sanding. Low cost shipping. Say what you will about the rest of the
   design but
    > IMHO this is a major breakthrough in low cost aircraft fuselage
   construction.
    >
    > With the right fasteners the same trick could be used for the wing.
    > Here is my idea for that. You build the core of the wing with
   composite
    > coated foam ribs one inch thick and the spar of course.
    >
    > You then layup the wing skins top and bottom on large plate window
   glass with
    > foam cores where applicable on the flat parts. You then bend them
   over the ribs
    > temporarily. Drill the holes for the drywall anchor screws.
   Temporarily install
    > the screws. Remove the screws. Remove the skins. Coat the ribs and
   spars with
    > glue and screw down the skins. I call it the drywall anchor technique
   or drywall
    > anchor wing.
    >
    >
    > Paul Lamar

   Paul,

   Steve Rahm is a genius, and this Vision design is great.
   His wing construction method varies from the method you've outlined, but
   results in the same type of wing (sandwich top and bottom skins with
   ribs and a composite main and rear spar).  Rahm wanted to avoid any
   fuel-susceptible foams, and his design does that, as well as being
   strong and very lightweight.

   I'm not quite following your wing idea.  The foam skin panels can be
   bent only as long as there is no  epoxy/fiberglass  on the inner surface
   of the panel, so how would you bend the skins to the ribs and then glass
   the inside surfaces of the skins  in your system?  Obviously, if there's
   only epoxy/fiberglass on the outer surface of the skin it will be much
   less stiff.

   Rahm's  wing design incorporates some additional gusset-like pieces to
   provide more bonding surface between the skin that is closed in last and
   the ribs.  As you've descried your method, the only bonding surface
   between the skin and the ribs (at least in the part you close in last)
   is on the edge of the rib, and i think that might be too little (but I'm
   no engineer)

   I've got a set of his plans, and will start construction soon.  It's the
   only composite plans-built conventional (ie.e non canard) designs I'm
   aware of.  The plans are actually separate spiral-bound books that walk
   builders through every step.

   I think mine will have a 13B in the nose.  It's a little on the heavy
   side for this design (Rahm says 300lbs is the firewall-forward limit,
   and the design flies great on 100 HP, so this is really overkill), but I
   think i can make it work with careful placement of cooling system
   components.

   Mark Waldron

   I propose a one inch thick rib so that would be plenty of surface
   area for the
   skin to bond to. Epoxy bonds are are about 3000 psi.

   I would not use a complete sandwich on every square inch of the wing
   skin. It is
   unnecessary as the curvature of the skin provides the necessary
   panel stiffness
   except in the large flat areas between the ribs towards the rear of
   the cord.
   There I would use chamfered 1/4 inch thick foam to stiffen those panels.
   Very similar to the way Steve is doing the fuse. Three layers of ten
   ounce glass cloth or carbon would be fine.  The shear strength of
   the composite
   in the plane of the composite would be the same and that is what
   counts when
   it comes to the torsional stiffness of the wing. Also in so far as
   the skin
   adds to the bending strength of the wing. See the new 3D.

   Build a section with just two ribs to test the idea.

   It might be easy to install a P51 type cooling system since you are
   building
   the fuse. from composites. The P51 type duct duct walls can stiffen
   the aft
   fuse. Make sure you use the Kuchemann and Weber trumpet shaped
    internal duct
   curves. A car ram air hood scoop can be used under the fuse. up side
   down.
    That would help the CG problem and ease the cowl layout.


   Another easier thing to do is use the quick and simple cooling
   system with
   a boundary layer splitter plate  aft of the wing under the fuse.
    From the side
   it would look like a P51 duct anyway.

   Paul Lamar


-- Paul,
I'm wanting to build the 4 place Vision and put a turbo'd 13B on the
nose.  I'm wondering what you think of the Spitfire type wing mounted
coolers he's using?

http://pro-composites.com/FreedomProject/09_Firewall_Forward/Radiator%20and%20Plenums.htm

                 --drury

He is using the old fashioned S shaped ducts/diffuser which don't work very well. He needs a copy of my book "How to Cool Your Wankel" from Mazdatrix or a copy of Kuchemann and Weber "Aerodynamics of Propulsion". If you do it and use the proper shape for the diffuser make sure you have a boundary layer air bleed above the scoop. That was the problem with the Spitfire. They tried to fix it with the sledge hammer approach and made the opening larger and larger hence added a lot of unnecessary drag. The Germans were better at it.

Paul Lamar

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