Fuselage, first up.

Its a built up profile. Aft of the wing looks a little like the tailplane structure under the 1/8" balsa skins. Forward of the wing its solid with 2 Oz CF cloth between the balsa skins and the core instead of ply doublers. The engine plates and undercarriage are recessed into the balsa to bear directly on the CF surface.

The inboard side is stiffened up and streamline with a balsa cheek cowl, which you can see in later pictures.

The wing is a little bit special. The construction method was devised as a way of getting a built-up structure to be very light using composite materials, namely rigid PVC foam, CF and S-glass. The idea was to have a moulded glass or kevlar D-box up front and idential CF/foam/glass hanging off the back of the d-box to support the film and TE. This is similar to how some fancy FF wings and combat wings are made.

Rather than make the moulds and find it didn't work, I decided to do a couple of balsa mock-ups to test the plan. One of those mock-ups was too good to ignore, so it became this very wing. Foam core sheeted with 1/16" balsa for the LE d-box, 1/8 balsa ribs and cap strips, 1/2" balsa TE and tips. Because all the ribs start out identical, I sanded off some of the 1/8 cap strips with the long sanding bar to get the airfoil even from root to tip. The airfoil started life as an Impact airfoil, but has evolved to suit the construction method. Basically that means a more forward high point at the tips and more aft curvature is some places, less in others.

All in one peice!

The LE, centre section and tailplane centre section were all covered in CF veil doped on. The other black areas are all stained. I had planned to cover it in clear film and have the coloured wood and CF areas matching and visible through the film, but this turned out to be a really bad idea, so I painted it in the end.

Power is an LA46 on uniflow with a special light muffler made out of a peice of aluminium deck chair extrusion. It weighs about and ounce, took 30 minutes to make and cost.... nothing 

The model weighs 43 ounces, span is about 56" and area must be around 650 sq. I can't remember most of the specs off hand.

So, how does it fly? Well at first it exhibited many of the failings associated with flapless models. Tail-dragging square corners for example... But with a few months of trimming and practice, it seems to fly as well as any flapped model I've had, especially in low winds. The one thing it still can't handle is a 12+ knot wind overhead. It just gets blown down the hemisphere with disturbing ease.

The experimental aspects of this model have been very successful. I've learned that is very difficult to substitute balsa where weight is such a factor and that the special construction method, while it works, isn't any kind of revelation. It may be worthy of further development when I have nothing else to do, though. As far as the flapless thing goes, it has been great not having to trim flaps, but on the other hand its good to have the option of trimming flaps! The next one will be the original fully flapped Impact derived design, with more composite content, more weight, more power.

Thanks Dennis.

I had  great day with it today. It was calm so I decided to try some new, longer lines. I went from .016" HT steel 62ft e/e to Brodak .015 SS 64ft e/e. The difference was astounding. This thing likes a bit of velocity, but I'm no good with fast lap times. I have noticed it would do the best turns coming out of the hourglass, where it is travelling quite fast and the worst at the top where it is quite slow. Going to the longer lines, a few clicks leaner on the needle and whipping into the hourglass has boosted my flight quality enormously... everywhere. After two very successful trimming sessions in the last two weeks, I think I'm going to see my scores really jump. Two weeks til the next contest

Did any of those in-flight pictures come out any good, Phil?

Thanks Phil. This one is ok:

Not as close to the wall as it looks