Ace bandages only put pressure on the curved parts 

That simple, build a cylindrical fuselage.

I think you'd have to bring the pressure down enough so that you boiled the water out of the balsa (without crushing it), or use vacuum + heat, or figure out a way to pull a vacuum but get airflow.  None of these seem to be easy to me, although the vacuum + heat method might be doable with little more than the right bag material and a day in the kitchen when SWMBO isn't home.

If you could pull a vacuum and heat it up to 200 degrees F or whatever "wood bending" temperature is, you should get a better "mold", too.

At 20 degrees C (roughly room temperature) the vapor pressure of water is around 2.3kPa -- compare that to atmospheric pressure of about 100kPa.  So at room temperature, to boil off the water in the balsa, you'd need to pull well over 29 inches.  Even then, you'd only be just starting to make things boil, and who knows what water's affinity for wood does to the boiling point?  You may end up squeezing more water out of the poor wood than you do boiling it off.

Bake things at 100C, and the vapor pressure of the water goes up to atmospheric -- so to get the stuff to boil off, you only need to pull a nominal vacuum.  This means either:

• you can pull whatever you want to get the molding to work, or
• you'll dry that sucker out so bad it'll turn to dust when you let it cool.

Unfortunately, it looks like you have to get pretty close to 100C to start seeing real effects, because the vapor pressure is a mostly exponential function of temperature.  See:
http://en.wikipedia.org/wiki/Vapour_pressure_of_water

Could you vent your vacuum form to a cavity stuffed with silica gel packets? Alternate idea...there's a beaded product that goes into a plastic dehydration bowl thingy...maybe easier to pack into the form. Any FM or hardware store should have it.   Steve

Edit: Another idea just whacked me in the noggin. You can buy an electric powered doodad that is supposed to keep your boat dry, etc. It's cylindrical, and has a 110v. cord out one end. I have no idea how it works, but I saw it in the Cabela's cattledog. This is more your speed, Howard! Technology that is a puzzlement...perfect!  

Here it is, in all its glory. Apparently a convection heater.  Have you considered a controlled air leak, to get some airflow through the length of the molding?

http://www.cabelas.com/product/Golden-Rodreg-Dehumidifier/733530.uts?Ntk=AllProducts&searchPath=%2Fcatalog%2Fsearch.cmd%3Fform_state%3DsearchForm%26N%3D0%26fsch%3Dtrue%26Ntk%3DAllProducts%26Ntt%3Ddehumidifier%26WTz_l%3DHeader%253BSearch-All%2BProducts&Ntt=dehumidifier&WTz_l=Header%3BSearch-All+Products

Howard i have tried the wet balsa in the vacuum bag with no success. The wet balsa and the mold buck with ace bandages work great on Impact,SV22 and Saturn. The flat parts of fuse hold down perfectly.
Photo#1 Molded balsa shell
photo#2 SV22 fuse
photo#3 wet balsa ace bandage over fuse buck
photo#4 composite wood and carbonfiber SV22 And Impact fuse. NOTE:The two fuselages are molded balsa composite
Jose Modesto

Not much filling and no warping. It is a little on the heavy side though.

Wonder if there was a way to mill the granite down to shells just some tiny fraction of an inch thick, just to say you have a granite plane....!

Howard,  if you are using contest grade balsa,  you don't need to wet the wood.   The atmospheric pressure is enough to form the wood to what ever you are using for a mold pattern.   Just look at what happens to a metal can when the air is pulled out of it.

Howard,
Why wouldn't it work simply to add dry pieces of scrap balsa on top of the flat areas for the ace bandage to press against?