Stunt Supreme--The Airplane

[Dave Hull]

I was searching thru some old magazines (American Modeler, March 1961) for our flying field history and came across a photo of a Hi Johnson airplane that he called the "Stunt Supreme."  The caption says it has a 60" wingspan and counterbalanced flaps.

The example shown was built by Bob Beach. The article further claims that it is a "swept-wing" design, but looks pretty conventional in the picture, although the flap hinge line may be swept aft. "It is completely symmetrical--wing, stab, and thrust line are all on the same line. The leadout wires are not swept back, no offset is used in the engine, both wing panels are the same size."

"Unique flaps are aerodynamically counterbalanced 24% ahead of their hinge line. Plane is big; span is 60" with 670 sq. in. area, 44-1/2" overall length. It is named "Stunt Supreme" to match Hi's latest stunt engine."

We remember the Johnson Stunt Supreme engine, but this is first I had heard that there was a plane of the same name. Was more than one ever built? Do plans still exist?

[Dave Hull]

This might help.

[Ken Culbertson]

Interesting design.  I see that the search for the 5' corner dates back a ways.  The flap TE is straight, and the wing is swept.  I think having the pivot point on the flaps behind the LE is a good idea but not so much that it allows the flap to make a hump at the wing TE or actually allows the flap CL to go above the wing TE.  There are other ways to take pressure off of the controls.  This looks like the Friday the 13th version of a trimming nightmare.  However, if we don't try things we will never have anything better or different.  10 points for originality!   

Ken

[Steve Dwyer]

The model photo leaves me remaining uncertain how the design achieves a counterbalancing effect on the flaps. Are the lumps actually forward protruding counter weights on both the top and bottom? Here's a photo showing examples of balancing control surfaces.

[M Spencer]

YOUR pictures  above'r of MASS Balances
the muddle pictured here is of a aerodynamic ' balance .

So theres TWO .  on ar udder , the piece forward of the hinge , lightens the pedal load . But they want some , for ' control harmoniseation ' .
Similar G per movement & V c V . so they dont pull the wings off . One or two had mass ( weight ) balances , conected into the elevator cable runs ;
so as the pilot wouldnt be able to overstress the airframe easily , as the mass of the mass increased the pull required , the harder the ' turn ' was .



From Here https://forum.dcs.world/topic/126295-why-is-the-spitfire-mk-ix-still-unstable/ if you want a headache .
the PICTURE ofthe stunt Supreme has a swept hinge line , from the look of it . scooping more air the further in toward the fuse .
My original G 51 Spitfire , held track well in gusts / rought air . In manouvres . Elevator Aero. Balances . ( the bigger shape ones )
AND a ' heavy ' 3 ounce pushrod , as a dampner . ( on relitively short horns ) the figuring was maybe a bump in the air would get negated .
Seemed to work , on a good still day , featherlight & fingertips - twitch the handle from inside to outside - you could discern the inirtia , as you ' threw ' the pushrod across neutral .
BELIEVE IT OR NOT .

Anyway . a mass balance , the elevator would sit flat , or where you set it . If the cables were off . TheForce deflecting it airbourne , is countered by the aero ' bit ' hung forward -
so that mortalls cam make them move and so dont end up underground . Apparently Spitfires could pull up sharper than Me 109s , so the 109 could be led into the deck , in mist .

LOOKING at the model puicture further - you see the HINGE LINE is straight . Whereas the trailing edge appears to be going forward more , inboard . to accomodate the aerodynmaic balace flap front .

This Way , you could twist your flaps aerodynamically !


Id think youd want rather stiff flaps or it could start to get rather intresting with these .