Brian,

You'll love this part. See the hole at the end of the elevator? That's a spot of epoxy in the hole where the tube runs for the hinges. To get the elevator off I just drill out the epoxy and slide the brass tube back out. That's going to be a lot easier to pull off the old covering and make the new cover a complete envelope.

Tim

Tim,

I really like this.

Reading up a little on frise ailerons and adverse drag/yaw, I am wondering if the frise style deflection you have on the elevator is causing the problems you described in your hammerhead maneuver???

My thought is to pull the pivot point closer to the TE of the stab to eliminate a little bit of the extra drag.

I could be completely off base.

Any thoughts?

Brian

Brian

Like full scale planes, if you center the tube in the center of the LE of the elevator it will simply pivot in place. Rotate the elevator and the gap remains the same at the hinge. If you were to cut off the actual elevator you would have an round piece of balsa the thickness of the TE of the stab that could rotate infinitely without changing the gap between the LE of the elevator and the TE of the stab.
If you were to move the tube forward it would rotate the same but when the elevator is deflected you would have a gap between the stab and the elevator. So the way I installed it is the the ultimate in clean drag-free design so I don't think it would be the issue.
The stabs are very thin and it may be possible that since I used a 12 oz fuel tank and it was balanced without fuel I'm thinking it may just want to fall forward because of balancing issues. Then if we consider the Weight X Arm = Moments formula and look at my off-road style wheels that make it look like a 4x4 red neck pre-runner, those mudder tires are sticking out in the air causing a lot of drag but also with a lot of moments of force making the plane rotate laterally , it may be possible that they are also helping to pull the nose forward.
Someday if the opportunity arrises I'd like to stick it in the wind tunnel at the University and find out what's going on. I could put on some thin pylon racing wheels and see if that affects it, and try to take off with 1/4 tank of fuel too. Then I'd know if either one of those is the issue.

Tim

edited above

This is the Dirty Birdy wing. I will put some 0.010" G10 sheeting about 1/4" wide on the top and bottom of the trailing edge of the wing that will cover the rest of the gap but you can see there will be no gaps for adverse effects.





However, could it be possible that it is too clean and not enough drag is created that keeps the tail down? I'm going with the wheel or excess fuel issue because it happens just as the stall occurs. I'll try to get some video.

Tim,

Boy, if that is how the elevator looks, than I was way off base. And that wouldn't be a frise set-up. My apologies. I don't think that is your issue any longer.

Flat out amazing craftsmanship. I definitely want to apply this method to my SK.

On the subject of the Dirty Birdy, I finaly got to see one fly the other day. Retracts and pipe. Wow! That thing sure grooved. And FAST!!! I could only imagine what the UFO must be like after seeing that.

You have good taste in airplanes, sir.

Brian

p.s. I'll try to stop posting so much.... I find that hard to do when I find something new and interresting to me.