Hi Larry,

The short ans. is:

1. Along the cord line (fore and aft), most of the force is located around the high point of the wing, in our CL planes case this is most often where the main spar is located.

                                      .    .   
                                .                .
                           .                       .
                        .                             .
                     .                                  .
                 .                                        .
              .                                            .                                                                  . .
         .                                                   . . . . . . . . . .......................................... . . .   .

         
        < ----------------------------  AIRFOIL CENTER LINE ---------------------------------->


The above is a very simple "crude" graph (due to my poor dot drawing skills ;-), but it gives you an idea of how nonlinear the lift forces are distributed along our airfoils.

Any spars located fore or aft of the high point are usually there more for torsional stiffness than for combating lift forces trying to fold the wing, but they do help a little. The Morris (Russian) wing system is in the perfect place.  ;-)

2. If you are looking for the forces along the span of the wing it is amazing to see how concentrated it is near the center. As an example in our very highly stressed RC ACRO planes the CF tube spars are only about 32" long in a 110" span wing. The female part in the wing usually extends another few inches to distribute the forces smoothly to the rest of the wing, without a sheer point. Then very light spars continue for the remaining 1/3 of the wing out to the tip. This reflects the force distribution on the span of the wing. There is very little stress on the outside 1/3 of each wing half, no need for big spars out there.

The Morris system is well done (I have one). Once the unit is attached to the wing spars (thread, or CF) the system becomes bullet proof. This attachment is the only potential weak point if not done well.

IMHO all CL designs will someday come into the modern world and leave their 1940s construction methods behind. Someday they will all be plug in wings using CF (or aluminium) tubes, like the vast majority of all other models today. Easy to construct (for a factory, or DIY builder), light, very strong, and inexpensive. This also makes take-apart very easy. :-)
 
In CL it may be easier to use Two smaller tubes (1/4", like arrow shafts or CF tubes like we use in our tail surfaces in our larger planes) one on top and one on the bottom. This allows for a conventional location of the bellcrank, but there are easy solutions for this issue too.


THE LONG ANSWER:  Begins below ;-)

http://mdob.larc.nasa.gov/Conference/gumbert/cfd01_gumbert.pdf

More Ref. materials here:

http://www.amazon.com/s/?ie=UTF8&keywords=aerodynamic+engineering&tag=googhydr-20&index=aps&hvadid=3771221187&ref=pd_sl_380t0q8wuc_b

If you were not 400 mi. away I would loan you some of my text books on this. They make for exciting reading. ;-)

Regards, 


     .                                                                                     .

Your right Larry, that would help in trimming the plane, especially a new design like yours. It would be very easy to do in the tail/stab too. It is a simple, neat system that we use. It would work great in CL.

I wish I was not so lazy, I would like to build a CLPA plane that copied the construction of my beautiful Extra 300L with CF tubes in the wing and in the tail. Even at 108" wide and 98" long it comes apart quickly and then easily fits in my minivan along with my smaller 78" plane. :-)

Our CL planes would take up so much less room in our shops/homes/cars if they were take-apart. And they would be easy to ship to faraway contests too.

Your new take-apart plane is awesome, I look forward to seeing it fly in 2010 :-)

Warm Regards,