Topic: Twin Mustang.

Pete
Will the same aerodynamic theory behind BERP tips on helo blades work on props? Since part of their job is to reduce compressability on the blade behind and allow the blade to operate more efficiently at transonic speed.

It will, but Mr Reynolds will drastically alter the results and I dont think there would be any any gain: in fact I think there would be a reduction in efficiency (otherwise it would already have been done).  The shape of blades and the tips are optimised for forward flight at a particular forward speed - like airliner winglets, not vertical performance acting as an air screw.  As you say, the shape of the tip is designed to be more efficient in the transonic region, but that shape also reduces the size of the tip vortices and modifies the way those vortices are shed so that they do not interact with the following blade.  BERP blades are much less efficient in the hover than the straight metal blades they replaced (was very noticeable when the Lynx got new composite blades back in the last centuary when I was on 815). 
Pete, a WAFU
 

Having now built a new patio and fenced off the garden so that we can let my daughter play outside, Building the twin can resume shortly. 'Watch this wotsname'.

I have a few(hundred) kits in stock, (as i store them for Mike)  and clearing up the workshop today i found 4 OS 32s...............  now who dares me!!   and how ineficient would 4 engines be and is anyone capable of molding a carbon center wing capable of holding 4 fuselages!!

Dave

wish my workshop had that kinda clutter laying about.. i can swap you some nuts, rusty screws and a spider

r u thinking of a quadstang or a P164? now that would be worth seeing. if anyone can do it i am sure 'the boy' can!! can you put up a visual of your vision?

Consider yourself dared Mr S. That would be so entertaining :angel:
Pete Tindal or maybe Alan Brown could be pursuaded to do the wing. If it was me I think I would just do it the same as the glass funfighters wing, only press the carbon under the skin instead of the 24grm  glass cloth. That would be incredibly strong.