Chuck,

good call. 2" of additional span sounds just perfect for a 15. I was wondering about those ribs but it sounds like it might be less work in the end than coring a foam wing. The top wing sheeting shouldn't have it tipping the scale at more the 6.5 oz like your previous one.

I actually just started planning out another small model (see my latest post in the Tsunami thread) for an identical 300W motor that I picked up (in theory as a spare...). I went for 43-1/4" span but the design has flat wide wing tips. The effective lift span is 40". It also has 310 squares compared to the Pico's 270.

I plan to hollow out the wood as much as I can without compromising strength. One thing that I was considering is producing oval shaped openings in the LE sheeting in between the spaced out outer ribs. This removes a fair amount of material. If done properly, it shouldn't weaken the structure significantly once covered. Of course, the model doesn't need to stand up to vibration. Someone built a full scale 58.5" span model to 3.5 lbs AUW so I'm sure it should be doable to build a 75% scale to < 2lbs AUW.

In any event, depending on your thoughts and outcome for the 42" Brushfire, I think I might go with that size too for the Webra 12 as I'd like to use a muffled pipe as opposed to the open pipe which is 2" shorter. The longer fuse should help to accommodate the longer pipe.

If you made tracings for the ribs, please preserve them! I sure could use them! Someone has to do the heavy lifting...

I look forward to some pics!

David.