2 Jun 11
I finally got fed up with the heavy wing situation. I've read of several "solutions" to the problem, but I've been skeptical of them. Most recently I read about Matt Dralle's change the aileron bracket to solve the problem. He said a tiny change made a large difference in correcting his heavy wing. I REALLY did not want to remove the ailerons and wallow out the bolt holes in the aileron brackets and reinstall and test fly and order new brackets and redrill them and remove and reinstall the ailerons. The main reason for not wanting do do the bracket fix was because my ailerons were different (in relation to the wing) by only 3/100 of an inch.
So, I decided to try the "squeeze the trailing edge of the light aileron" trick again. I first spoke to Van about it at SnF 2010 and he said use two 6 inch long 2x4s to protect the trailing edge and squeeze with channel lock type pliers. Well, that seemed drastic to me and the 2x4s are too thick, so I tried squeezing by hand - after all, everyone said it is easy to over do it. The had squeeze made no difference.
So, I cut two 12" long, 1" thick particle boards about 4" wide and using channel locks gave a slight squeeze to the left aileron trailing edge. Went flying and found very little difference. I think I allowed the edges of the wood to touch and therefore the squeezing action was applied to the wood and not to the aileron. I tried again making sure the pieces of wood were not touching. This time, the change was dramatic. I had squeezed too much and now the airplane wants to roll left! So, I'll have to slightly squeeze the right aileron to correct and fly again.
12 Jun 11
Well, I haven't totally abandoned the original wheel pant air dam idea, but I'm going to try a different approach. Tufting indicates the airflow control with the original air dams is very good. The air is flowing exactly as expected, but there was very little speed increase. So, I'm going to try another approach.
The way I made the first air dams was time consuming and the finished fiberglass pieces required LOTS of finishing work - sanding, filling, shaping, sanding, filling, etc. I want to minimize some of that work, so I'm going to use roof flashing to make an aluminum shape over which to lay fiberglass. I believe I can better control the shape and the surface of the aluminum form will provide a more finished shape - thus needing less finishing work. The roof flashing is about .010 thick and thus us easy to handle and to cut. I'm trimming it to the minimum size and then I'll lay fiberglass over it, remove it all and remover the aluminum.
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The thin aluminum is taped in position. It's eacy to see the fairing will direct air to flow under the tire while not allowing it to enter on the sides. The air dam portion of the original fairings is gone. With this arrangement, the fairing can be brought very close to the ground in front. the sides and aft portion will be trimmed to allow more ground clearance. | |
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The unfaired pants clearly show the portion that will be faired. | |
22 Jun 11
Short flight today to test aileron squeezing to see if heavy wing situation is corrected and to video tufting of the Speedy Cuffs.
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Left is Drift camera mount on gear leg
Right are links to video of the tuft tests |
Here is a video of the standard Van's pant/strut combination. As suspected, there is significant turbulence in the acute V angle between the pant and the strut Video of standard pant tufting
Next is a video of tuft testing after installation of my Speedy Cuffs.
My initial take is that I will extend the trailing edge of the Speedy Cuffs in order to create a smoother transition to free stream air. |
The heavy wing problem is over corrected. Now I will have to squeeze the right aileron trailing edge a bit to correct the overcorrection. At least something is working.
30 Jun 11
Time for the annual Condition Inspection. Back to flying when it's done.
Next update 1 Jul 11