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Bench top for 9A ailerons/flaps

skelrad

Well Known Member
Friend
What’s the length of the ailerons and flaps? The manual says you need a 2x8 foot perfectly flat bench. I’m just wondering if it’s truly 8 feet, or if they just said that out of convenience of cutting an MDF panel in half. My workbenches can be pushed together to be 8 feet long, but they wouldn’t be perfectly flat because of the joint between them. I was thinking of grabbing a free hollow core door on Craigslist for a bench top, specifically for building the ailerons and flaps. Doors are not 8’. Would that work, or do I need to go grab MDF? My experience is the doors tend to be just as flat, if not flatter, than most 2x8 stock.
 
You want a FLAT surface and long enough

You may be best using one of your existing tables and getting some straight 2x4s and screwing them on edge to the side and ends making sure they are fastened straight and flat frame and then putting a piece of 3/3" on top. You want the table to be correct and long enough. I cant remember how long it is but I do not think it is 8'. I will be at my hangar later today and will check.
 
2x8 ply

I used 2’x8’x3/4” mdf. Have the store rip the mdf at 2’ on their panel saw. Mdf is heavy and hard to Handel a 4 x 8.

With the remaining 2’, cut two pieces 3 1/2” ( perfectly straight) with a good table saw. These will act as a strong back vs. 2x4 stock. Attach together with an 1 1/2” lip from the edge of the 2’x8’. (Glue and Counter sink 1 1/2” screws) The 1.5” will allow for clamping. The 3 1/2”x 1 1/2” piece will act as a strong back keeping your work top straight. You can then attach to your work bench. Personally i would not use 2x4 stock as the strong back unless you can rip it straight.
 
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the ailerons are just a bit over 48", the flap spar is 80 5/8" I used 1x3's between the mdf panels because they were straight without ripping them, and i dont have a table saw
 
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Work surface

I used a 8’ solid core door - surplus from a church remodel. I also bonded a 1/2x4 steel flat bar to the back side along one edge to use as flat bucking bar to rivet the trailing edges/ wedge. Useful for all the trailing edges on the 9.
 
-9 flaps are just about 7', but having a little extra space on the ends is nice. I'd built several EAA101 tables, I put two of those together to make a flap table, using wood shims under the legs to get them level and flat to each other. Then I got a sheet of 3/4 MDF and some 2x2s to build the sacrificial top, and clamped that across the benches - the MDF-2x2-MDF sandwich isn't exactly rigid, so the benches supply the flatness. You want something that's good and stout, you'll be putting healthy amount of weight on it to hold things flat, so you want a surface that will not sag or warp. You also need some clearance underneath for clecos to stick through.
 
My 2cents worth

I built a table specifically for the flaps as Van's called out in the plans, using a single 2400 x 1200 x 25mm MDF ripped in half and assembled with 75mm x 50mm timbers in between. This sat on my regular bench, but to help with weight I put a couple of rope handles in each side so it was easy to move around. I'm really glad that I did this- I followed the plans to the "T", including all the drilling into the MDF for cleco's or clecoing directly into the table, especially for the trailing edge. Both flaps turned out within 2mm of perfectly straight over the length.
 
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