Typically, 1/2" slabs. The Flite Streak was odd, at 7/16", at least the original TF kit. Most designers that use a "built-up profile" use 1/2" for the edges and wing/engine/stab area, 3/32 x 1/2 diagonals (or foam core) with 1/64" ply outer sides, or perhaps 1/16" or 3/32" sheet balsa.

Some "Profile Stunt" rules may specify maximum fuselage thickness, often using the same specs as CL Profile Scale, which is apparently 3/4". I always wonder if there is any + tolerance on stuff like that, to allow for paint and such.   Steve
  

Tim,

I see you're still up?

OK, does that mean I shouldn't build my original Flite Streak? What kit is yours or scratch?

CB

The old J. Roberts kits for Carrier were 3/4" wide, 1/2" longerons with 1/8" sides. I think 3/4" is still the max.

If you are looking to build a larger model with a 46-60 engine, figure on using a 3/4 in. fuselage.  That fits the rulebook definition.  The bigger motors need the extra thickness to get a stiff enough front end.  I use 3/8 x 3/4 in motor mounts that go right to the surface of the fuselage.  The doublers are fiberglass or carbon fiber, at least 8 oz/ sq.yd for glass.  Carbon fiber could be less, 4 oz/sq.yd.  You can use 1/16 in. ply and 5/8 in. core wood for more stiffness pm a 60 powered plane.

For a stunt stick type plane(~3 in. tall fuselage), nice, light 3/4 in. wood all the way back to the stab should be OK and not make the plane tail heavy.  If you are going for something more scale, the fuselage should be built up behind the spar, either using a foam core and 1/16 in. sides, or some kind of geodetic 1/16 in. strip core. Rather than using 1/64 in. ply for the sides, go with solid medium balsa and .2 or .5 oz. cargon veil applied with epoxy for added sitffness.

If you are looking to build a larger model with a 46-60 engine, figure on using a 3/4 in. fuselage.  That fits the rulebook definition.  

(Deleted)

Overall, Phil's post has some usefull information.  However, the comment about what "fits the rulebook definition" needs some clarification.

There is no specified "rulebook definition" for a profile fuselage or a specification for a profile stunt fuselage minimum or maximum thickness.  There are no AMA official rules for any CL Profile Stunt event nor is there any unified unofficial rules for CL Profile Stunt.  Different contests might have their own defined fuselage width allowances for such contests, but my experience is that many do not.

The rulebook does contain paragraph 10, CL General, that gives a profile definition that outlines certain aspects of how the fuselage of a profile model should appear.  The CL General section also gives a table for the maximum fuselabe width for the several official CL Profile events - 1/2A Proto, Scale Racing, Slow Combat, Navy Carrier, Slow Rat Racing and Rat racing.  That table table also gives the maximum width "with additional reinforcements" for each of these events as provided for in this section of the rulebook.

Then, in the CL Profile Scale rules, a maximum fuselage and engine nacelle(s) width of 1 inch is specified with an allowance of a total width 1 1/2 inches for a cowl or cowls.

Otherwise, most of the the information provided in this thread is useful with the exception of the wrong specification in another post about Profile Scale.

Keith

Here's a typical West Coast profile stunt plane:  http://s1213.photobucket.com/albums/cc469/JimAron/Current%20Projects/Hydra%20B36/?albumview=slideshow

Here is something a little more normal for the Profile event in the Northwest.
Pat Johnston

Here's a typical West Coast profile stunt plane:  http://s1213.photobucket.com/albums/cc469/JimAron/Current%20Projects/Hydra%20B36/?albumview=slideshow

I hope everyone realizes that this link is a double slide show. The part showing Jim's rebuild is a must view. Thanks for posting, and yes, I'm interested in the profile fuselage responses, but have nothing to add there.

SK

My most recent is sort of a compromise, aimed at torsional stiffness. It's 1/2" medium balsa core, with some lightened trussed aft area. 1/16" ply doublers  extend back to the high point, where they are butted against 1/16" balsa sheeting. Nose has a 1/2"+ balsa tripler, and all of the fuselage except the right nose is covered with a layer of 45-degree bias .56-oz fiberglass, applied with West Systems resin. The plywood under the engine lugs is cut away and replaced by aircraft aluminum tapered pads for about 1.5 degrees of out thrust. So the engine does not crush the plywood. It is actually pretty light - and very stiff.

SK