My Fokker DVII Project

[scott5952]

Do you know what temper 3003 it was? It should have been followed with 3003 H something. I have included a comparision of the strength of 2024 and 3003. 3003 is obviously weaker, but on the other hand it is way less likely to crack in service.

Given that the box is really only a spreader bar you might be perfectly OK using some of the higher temper 3003 alloys. Basic I would just run a column stength / stability check and see if you get resonable results. Because of the large area involved you will obviously be fine in tension.

[Jeff Brooks]

yes, it is 3003 H, and I am unsure what is the right type now that it has come up in the forum. I want to make another one to see if the bends can be made cleaner. so I might as well load test the this one. I imagine the load test would involve crushing it end to end. and measuring how much weight is can take. any suggestions about the testing process I should be aware of before I do this would be welcome.

[scott5952]

Well, you could test it - but because the section is just a square it would also be really easy to calculate. This just basically boils down to a simple compression crippling / column stability problem.

But.... if you were going to build another one anyway, why not just order some 2024 in the O condition. This is dead soft material and will bend as easy as the 3003 you are using. When you are done forming, just send the section out and have it heat treated to the T4 condition. The heat treating is very inexpensive. The only issue you will have is that it will warp a little during the process, but this can easily be removed.

As a word of warning though, I would place some temporary pop rivets in to hold the section when you send it out (maybe 10 or so) to minimize the warpage. When you get it back though, drill these out and replace them as standard AD or D rivets. (don;t totally rivet it first as you don;t want your rivets heat treated too!)

[jumpinjan]

Originally Posted by Jeff Brooks

I imagine the load test would involve crushing it end to end. and measuring how much weight is can take.

I would think about the static forces involved first. At my first, quick look, the box is in tension. Next, what are the forces the undercarrage wing will exert on it, and so on.

[wilhelm]

Great work but where did you get your struts or did you make them yourself.

Wilhelm

[Jeff Brooks]

I ordered the metal from aircraft spruce and followed Achim's jig design to make them. my pieces are not as accurate as Achim's ... I don't have a mill to cut the parts. I cut a template out of cardboard, trace it onto the flat stock, use a drill, angle grinder & dremel tool to get the basic shapes. I am using gas welding.

[Roadhog]

Dear Jeff, All that I can say is "WOW." You are actually doing what so many of of have dreamed about. A few weeks ago, I received a book called "German Aircraft Cockpits 1911-1970" by Peter W. Cohausz. It is published by Schiffer Military History Books and available through Edward R. Hamilton Bookseller (he has a web page) for I believe $45 or $49, instead of its original price of $69.95.

One of the WWI aircraft featured in the work is the D-VII on page 48. You might want to take a gander at this since the photographs were worth the cost of the book to me (a military history writer).

Now sir, when can we expect an Albatros D-III? Good luck with your project and may God speed. Roadhog "Memento mori."

[Roadhog]

Dear Jeff, By the way, Peter W. Cohausz's book has a chapter on the Albatros D-V also. Roadhog "Memento mori."

[Jeff Brooks]

roadhog,
Thanks for the heads up ... i will track it down and get it.
I just spent the morning with Maximum08. We were comparing notes and exchanging parts.
I waste a lot of time learning to build a particular part, and it is a shame to have another builder go through it needlessly! He and I were talking about exchanging a few small pieces in trade. To cut down the wasted time in the learning process.
Those axle box openings I made were a bear to figure out how to do ... now they are easy!! Now I could easily crunch out those pieces in a short time! (anyone need axle box openings for a 2 " axle? ... I need a few small pieces in trade)
I am now going through the same learning process with working with aluminum!!!

[Jeff Brooks]

I realized that I had placed one of the engine support tubes in the wrong place ...

so I cut the tube off and cleaned away all the filler metal, being VERY CAREFUL not to grind into the tube.


I cut and spliced in new tubing in the correct position.