Bearcat plans, as requested...

[Pat Johnston]

Pete, as requested, the plans for the Bearcat.  This is the 40/46 size version of my 700 inch, 60 size Bearcat.  The Bearcat is pretty easy to build, especially for a semi-scale plane.  John Brodak build his prototype for the kit at 40 ounces, but at 45 ounces it will still fly wonderfully.  An equivalent flying plane is the Brodak P-40B.  The Bearcat is lots of fun and a ball to fly.
Pat Johnston
Round Nose Designs
Skunk Works

[Pat Johnston]

Might be able to attach a photo.

[David M Johnson]

Can you send those again?  I drooled on the first set...

Too cool. Thank you
David Johnson

[Balsa Butcher]

Thanks Pat, great looking bird - both plans and pic. The standard 3/32 fuselage sides should make for easier building than some other semi-scale designs. May have to give it a try. 

[Pat Johnston]

I have developed a little trick on the fuselage sides.  The original method laminates a chunk of 1/4" sheet over the front end of the 3/32" sides.  Instead, I use a front side of 3/8" stock which is but glued to the back 24" (plus or minus) of 3/32" side material.  A little internal doubler can keep this joint nice and tight.  Then the front 3/8" sheet side can be nicely rounded for a good looking round front end of the nose.  A laminated joint is eliminated with the ensueing problems of a thin lamination to do finish work on.  A much better solution.
Pat Johnston
Ever Designing
Skunk Works

[Balsa Butcher]

I like that solution Pat. With a little, careful sandpaper and razor plane work(and some 3/8 contest grade balsa) one could have a nice round fuselage contour with very little weight gain and a stronger fuselage to boot. Question: Plans show 1" dihedral on under each wingtip...is this correct? Brodak recently posted a change from 1" dihedral to 1/2" on the Spitfire, just wondering if this AD also applies to the Bearcat. 

[Pat Johnston]

I think that both planes should have 1" of dihedral.  I'll check the masters and find out.  If so, I suspect that the change on the Brodak plans should not be there.
Pat

[Balsa Butcher]

It's on the main Brodak web site under "Announcements". My interpretation of 1" dihedral under each wing tip would make it 2" of dihedral for the wing. 1/2" under each wing tip would be a total of 1" for the wing. I read the plans as recommending 1" per wing tip or 2" dihedral. Maybe John interpreted it differently.

[Geoff Goodworth]

I'm always confused about where we measure the dihedral on a stunt model with a thick symmetrical airfoil.

On gliders with airfoils that have flat or undercambered airfoils, the dihedral is clear. On stunt models, I assume that is it measured at the centreline of the airfoil and that requires some compensation/calculation.

Maybe we need some clarification of that point.

[Pat Johnston]

Geoff,
Good point about measuring the dihedral.  It is to be measured from the centerline of the root to the centerline of the tip.

As far as the Brodak Bearcat and Spitfire go, the dihedral should still be in the 1" range.  That said, there could be a possibility that something closer to 3/4" to 7/8" may be just a little better.  A lot of this depends on things like the weight of the wheels and what weight wood is where.  Also the amount of cockpit detail which is somewhat above the CG.  This is a little of the "Black Art" part of the design when estimating the actual vertical center of gravity.
Pat