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Metal Hardware For Acrosport II Wings

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aerofan

Acrosport 2 Builder
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For those of you who are not building from kits or using CAD and CNC to cut out your parts the following article describes how I cut and shaped the metal parts for my wings.

If you will take the time to look at my other posts it should be obvious that I have absolutely no idea what I am doing and have no sense of humility.
PlansPatternsandParts.jpg
So far I've made upper, lower, and center section wing attachment brackets. Pictured here are the paper templates glued to 1/16" plywood on the lower left and the final products on the right.

Here are some of the tools an methods I've tried to get to this point.

Electric Metal Shears.jpg

This is a fine tool for cutting thin metal sheets. It allows you ample control. It's not very good at cutting 0.090 or thicker. It also tears out a strip of metal about 1/4" wide so there is plenty of waste. It is quick and simple to use.

Broken JigSaw.jpg

This did not work out so well. It broke the third time I used it. It also had a nasty habit of turning left making it really difficult to cut a straight line.

Good JigSaw.jpg

This worked out much better. With the correct blade it cut through a sheet of 0.090" 4130 like butter. It is much better to let the tool do the work rather than try and force it.

Angle Grinder.jpg

The angle grinder broke the first time I tried to change the disk. The button that locks the disk in place so you can remove the nut is held in place by a plastic tube. It is not as strong as it needed to be. To change the disk I either need to disassemble the grinder head or put the disk in a vise. Problems aside the anger grinder creates the best cuts with the least waste and is the most maneuverable. The down side it is very dangerous and it introduces a large quantity of particulate matter into the air that requires a ventilator.
Patern and Calipers.jpg
I start by drawing the part to scale on paper. Then I glue the paper to 1/16" plywood. I drill small holes so I can bold all the pieces together.
Rough Cut Ready to Drill.jpg
Some of my early attempts turned out pretty rough around the edges. After the blanks are bolted to the pattern I put them in a vise and had at them with the angle grinder. This was a mess but it worked. I dressed them up with a file followed by rough and then fine sand paper.
Blanks in vise.jpg
This method works but takes an enormous amount of time and effort. There is no chance that someone with my skill set and temperament can make all the metal pieces necessary using this method.

Mill.jpg
My combination lathe/mill to the rescue. I needed to add some extra clamps to the blanks because I did not have a vise that was wide enough to support the pieces. I was limited to taking about 4/1000 per cut and my largest end mill required several passed because it was not as wide as the brackets. This took a fair amount of time but it was easy and produced the best results.

Having proper tools makes a huge difference. I wasted lots of time, wood, and money last year because of my cheap table saws tendency to cut at odd angles.
Delta Table Saw.jpg
Problem solved. I was able to cut my spars.
Wing.jpg
Those of you who are building Acrosports will notice that the ribs are incorrect. I just wanted to see that they fit and that the spars would be parallel.

The first set of brackets I made took two weeks. I'm not proud. The last set I made to about 4 hours over two days.

I hope that there is something useful to someone here.

Cheers,

David
 

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