I am no aerodynamical weeezardo (THAT'S FER SURE! )....but the quest in building any plane that I build, is to keep it not only light in weight....but more importantly, keeping the frame  and control system from flexing, which will keep that model performaning better for a longer period of time before the ravages of fatique begin to take its tole.

Try to remember, that when control surfaces bend or flex this will effect not only the flight path...but also require the pilot to make constant corrections at the handle.

 Any stunt modeler who has ever built the older stock Nobler with that holyer' than thou' fuselage...or didn't take care to beef up the stab and elevators with the right selection of quality balsa....knows the feeling and what happens when flying that model in high wind conditions.

The Nobler wasn't the first or the last model to experience not only flexing of the airframe (due to design flaws...but equally AND MOST IMPORTANT IS FLEXING OF THE CONTROL SYSTEM ITSELF can reduce the flying quality and consistency of performance.

 So often many modelers beef up the airframe..but IGNOR  bushing or beefing the pushrod, bellcrank etc and choosing the right stiffness for flaps, elevators..etc.

Actually to me, the control horns themselves are the last buggaaaboo in the control line stunt model flexsation-demon thangie' that bug me the most.

It just takes ONE ITEM IN THAT FLEX FOOD CHAIN control system ...to make a "sow out of silk wallet!"
Years ago...I had a beautiful old Kenhi Panther that flew awesome in light air...but in the wind it hunted...opened up on the square corners with a bottom back-corner hourglass from HELL!

After cutting into the body....I added some plywood bushing-stops  to just one main fuselage former and that inproved the flight  performance.DAY AND NIGHT difference.

Like the duel line precision event sport kites that I fly, the frame stiffness is very important for proper tracking but equally important is the FRAME BALANCE CG POINTS THEMSELVES.
Frame flex during the power faze is important but also the balance point is equally important. If a frame (be it those kites...or a stunt model) when under flying "G" loads...the weirdest things can happen and effect the flight path. The kites however fly from specta bridles...and even a soft bridle line can effect the most perfectly constructed frame.

Being a human bein'...we tend to teach our pea brains to train our muscle memory... then we go about trying to understand  our models strange and individual habitual flight chacteristics,

 INSTEAD OF TRYING TO FIND OUT WHAT IN THE FIRST PLACE IS CAUSING these flight path changes that take place under different flying or weather wind conditions.

Amazing how many flyers just give up and simply LIVE WITH THAT LACK LUSTER MODEL and in the end, they just  LEARN TO EITHER LOVE OR LEAVE UM.

Kinda sad that we just give up on that model with the poor trim problem and then in some cases find it easier just to build another model...and go through that same process over and over again as we continue the fleeting search for the HOLY GRAIL OF STUNT MODELS.

bottom line divil...
My feeling is...that a twin or triple boomed stunt model has SOOOO MUCH GOING FOR IT!
I finally found one slide that I took of Jim's & Jack's 68 nats Torino....just before that beautiful 1st qualification flight of the day.

Jim,

Just an additional note on your question concerning longer tail moment on the boomers.

In general they had the same momments as any conventional airplane. The swept wing (eg "Sea Vixen") designs have a longer tail moment, but this is because the center of lift and therefore the CG is further aft. If you take measurement from the center of lift, you will find that there is really little, if any, difference in the respective tail moments.

As I noted on the other thread, Jack's "Sea Vixen" article mentions that he lengthen the tail moment and locked the center flaps to get more turn due to the high tail.  I had a telephone discussion a few months ago with Jack about this, and he said that the flap lock out was probably not necessary since the original short tail momant was probably the problem. At the time he had also decreased the stabilizer area to get more turn. This is why the drawing shows a radius at the leading edge of the stabilizer next to the rudders.

With a clean piece of paper, the decreased stab area would probably not be required on a new design.

BTW: Jim Vornholt won Senior at the '60 Nats with the "Carousel"

Interesting what you say about "trying to HIDE THE FACTS from the judges..by using bulbola' rounded bodys in order to "blend the mistakes.
However anyone who saw that flight of Jim's in 68 with that Torino....I THINK IT HAD THE OPPOSITE EFFECT and really impressed me and a bunch of others that were blown away by his crisp and accurate corners and shapes.
bottom line:
If your flight pattern is outstanding...the rest is gravy. Nothing seems to really HIDE MISTAKES from a quality judging staff anyhooo. Right? U BE DA JUDGE! 

If what u say is true MASTER LOU CRANE. How can you explain to  RICH LOOMIS...WHO BLEW AWAY THE COMPETITION at the 67 nats with his BOOMER!

Thinkin back....if I remember talking with Dick Mathis at his 2nd place win in 68 about his CHIZLER. He too had mentioned that he DESIGNED the Chizler with not only fat rounded fuselage lines (to blurrr the straight line stuff) but also DESIGNED a paint scheme that would also help blurr the straight line stuff.

THEN COMES ALONG BART KLAPINSKI...with that beautiful Rakish lean lined model with the swept rudder and BLOWS AWAY THE COMPETITION.
WHY?
My unworthy guess....would lead me to believe that his win had NUTTIN TO DO WITH THE BODY LINES of his MODERN THIN RAKISH DESIGNED JET STYLED STUNTER...and simply just boiled down to his truly AMAZINGLY FLOWN PATTERN THAT RULED THE STUNT CIRLCLE  THAT DAY.
Bottom line: If you are a consistant and quality flyer....I HIGHLY DOUBT that the body design lines of the airplane will actually make much of a difference and hopefully the best pattern flown will or SHOULD BE THE FINAL FACTOR.

Schultzie,

I don't think anything I said went against your spot-on remarks that the best pattern will get the best score!

Playing with shapes of the models most often makes the flier feel better. If it helps the way a figure looks, so much the better. Even if it doesn't, but the flier thinks it does, he may pick up enough confidence to really cut loose with his best.

The long, pointy sleek models DO look good in GOOD turns and corners, but they CAN make any mistakes, even slight ones, look much more obvious. The guys who won with the long lean monsters flew their win.

"Loose nut at the back of the handle..."

I have noticed on swept wing planes the lead outs  exit in different positions, from in front of the leading edge to any positions all the way to the trailing edge. I wonder which is correct?
Willis 

Lou,
"Jim, Don, Tom...
Among y'all this is very well covered"

We are having fun discussing something different for a change.
Fuselage shapes have a definite effect on "presentation". Remember Sirotkin's "Space Hound"?.. it had a round fuselage bottom to accent the round maneuvers in the old FAI pattern.

Dennis,
You are right about the evolution of Jack's swept wing designs.
The "Sea Vixen" leadouts "look" too far forward, but I ran the numbers on it yesterday. The leadouts are about 18% of the MAC... about where we have them on our "modern" stunters!
The "Torino" leading edge sweep looks closer to conventional, with a aft sweep at the hinge line. The planform doesn't appear to be too much off the norm. In the above picture, the leadouts "look"" to be very far aft, but I'll bet that they are about where they should be. I'll have to get a set of the "Torino" plans and run the numbers.

Hey, do you think we will drive Lou nuts if we all have Boomers at the next VSC?? (Just kidding Lou)

But, it would be neat to have a lot of Jack's airplanes, as a tribute to him!

Don,

My Shark .45 does O.K. on squares.  Of course it's balanced pretty far back in the CG range.

In fact so far back that it sometimes wants to hunt a little in level flight. 

Jim Pollock   

EXHAUST SMOKE TRAILS...are sometimes....so so NOT SO  happy trails after all. I can remember judging at a contest where a tree cast a shadow onto part of the flying circle and the back ground was trees shaded by the sun...

(in other words...we were flying and judging mostly in bright sunlight but the dark background really ACCENTED the exhaust from the models in flight....

Although we tried to ignor the effect....but it was virtually calm and very little wind. The effect of the flaps being deflected and also the compression of air..(? boundry layer ground effect)?? My dement brain to typing fingers...can't seem to put this into perspective.
Bottom line:
Have you every played tennis or baseball...on a court or field that is partly shaded...Uhhh? Leo??? Delta Park....uhhh The NE side of the old Boeing Aerospace center next to the Indoor Tennis courts? All these flying spots were horrific to fly a decent pattern on....or even worse....ATTEMPT TO JUDGE THAT EVENT?

WHAT WAS THE WORST PLACE THAT YOU HAVE EVER FLOWN OR JUDGED AN PA event.

(Next!) Choosing the right color scheme FOR THE FUSELAGE OF A STUNTER  is of PRIME IMPORTANCE "VISUALLY SPEAKING!! Although one of my favorite colors for a stunter has always been Deep Dark Metallic Red and maroon trim...BUT ON A BODY LINE!!! IT CAN BE BOTH FATAL! Not only from the flyers view point but equally bad...if one has to judge that model in flight.
REMEMBER STUDIES HAVE PROVEN THAT DARK RED IS THE FIRST COLOR THAT OUR EYE CAN NO LONGER SEE WHILE IN MOTION. (That is unless you have BAT OR BARN OWLS ultra violet...cones installed in your optic nerve cells and demented EYEBALLS!)

Anyone make sense of this drivil crappolllaaaaaaaaweirdo....thought pattern. See what happens when your job for almost thirty years has been suckin toooooooooooommmmaaaany paint fumes. (or was it the Rainier Brew?)