Steel Instead

I decided that I didn’t like the idea of using aluminum angle as the aft support for the panel that goes under the door. This was mostly because I couldn’t think of a way to attach the aluminum angle very cleanly, so I figured I’d try to make one out of steel. I would be able to weld the steel to the fuselage, making for a much cleaner attachment. I saw that Bob specified .032 mild steel for the bulkhead at the trailing edge of the boot cowl, so I used .030 for this piece. It took me a little while to get it cut to shape and to bend it on my little toy brake, but I was very pleasesd with the finished product. I bent the trailing edge also, partly to increase the strength of the part and partly to be sure that it doesn’t chafe the fabric.

The bottom is aluminum angle, the top is the steel before bending

Aluminum Angle on top, steel blank ready to bend.

Aluminum Angle on top, steel blank ready to bend.

Aluminum Angle on top, steel blank ready to bend.

I made a paper template of the flat piece before I bent it.

I made a paper template of the flat piece before I bent it.



I was a little bit worried about welding on the longeron. Making hangar doors is one thing, but welding on an expensive fuselage is another. I had a scrap piece of 3/4″ .049 (Bob’s T11) tubing like that of the longeron, so I started practicing. Since the tube is .049 and the tab is .030, it took a little practice to learn how to keep the heat off of the thinner piece. You can see the result.

Here you can see that the longeron sample tube is .049" thick compared to the .030 tab.  I wanted to practice dealing with this difference.

Here you can see that the longeron sample tube is .049" thick compared to the .030 tab. I wanted to practice dealing with this difference.

It looks pretty good in the middle, but the ends need work.

It looks pretty good in the middle, but the ends need work.

This is a bad one.  I started using narrower pieces just to make it harder.

This is a bad one. I started using narrower pieces just to make it harder.

Here is the end after trimming and ready to fit.  Note the clearance for getting the floorboard in and out later

Here is the end after trimming and ready to fit. Note the clearance for getting the floorboard in and out later

Here you can see the cleco side clamp holding the bottom ready for tacking.

Here you can see the cleco side clamp holding the bottom ready for tacking.

Here is the left side in place

Here is the left side in place

Here is the left side in place

Here is the left side in place


I used a 90 degree die grinder with a scotchbrite pad to remove the paint on the longeron and door sill, which was quite effective. In the end I was pleased with the welding, and now I just have to make the other side.