Warbird Information Exchange

Hello! New member but I've lurked here for years. If this is the wrong section feel free to move the thread.

Has anyone attempted to stretch-form new portions of the bf109 aft fuselage? I'd like to try making some for a non-flying replica. I have a CNC machine capable of making the molds from a hard wood like maple. Pretty sure that would work for at least a set of fuselage shells. Or maybe delrin?

Are the non-flanged sections of fuselage stretch formed at all, or are they just cut from flat sheet? Does anyone know of any books or resources for how to stretch form and tables to determine what thickness I need to start with? Can anyone recommend an alloy that will form well, and be strong enough for ground handling without heat treatment? 6061T4?

Sorry for all the questions, this aspect of metal forming is very new to me. Thank you!

You might do a search on Craig Charleston in the UK or Flug Werk in Germany. I think Airframe Assemblies on the Isle of Wight in the UK might also have done this already.

There was a good article with quite a few good photographs of Craig Charleston's shop and his forming of -109 fuselage skins in an old issue of Warbirds Worldwide. The magazines come up often on Ebay but I don't know the issue # off the top of my head.

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Excellent, thank you. I will search for that issue. There are a few with Black 6 on the cover, I suspect it's one of those.


Research is paying off, this company in Germany stretches their 109 skins on 'slippery' plastic forms. This little project is starting to look doable!
http://www.leichtbau-gmbh.de/formenbau.htm

I love the simple jig Meier Motors uses for building 109 fuselages. Putting the thing together seemed very daunting until I ran across this.
http://meiermotors.com/images/stories/B ... 0Kopie.jpg

Found this pic of Airframe Assemblies' stretcher on their Facebook page. Looks like a very basic bottlejack contraption.
https://sphotos-a.xx.fbcdn.net/hphotos- ... 8438_n.jpg

I suspect that the one Airframe Assemblies is using still requires some wooden hammering to form the flanges after the hydraulic cylinder has done its job.

Check out these guys as well

http://hegis-me109.blogspot.co.nz/

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The link DaveM2 provided might be the right one for you, as you plan a static project, and Hegi`s one is a static one too. Maybe there are some aspects you do not need to follow when not building an airworthy plane. You can follow this project here as well, if you like:

http://warbirdforum.de/forum/thread.php ... d18c479079

You will need to register though.

Michael

I really like the aluminum over wood method. I've thought about wood ribs wrapped with masonite, but hadn't considered a hybrid.
This guy makes some really nice german planes that way. http://www.luftwaffewest.com/me109.htm

Still want to attempt stretch forming them the original way, it looks like an interesting process.



Maybe, and that wouldn't be a dealbreaker. Before I learnt that they were stretch formed, I was planning on just hammering them over wood forms like a typical fuselage rib flange would be done. I figured the small flush-skin offset could be bead-rolled, then strap the skin over the form and hammer the flanges down. This might still be an option.

Holy Schmitt!!
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Sounds like a really neat project. Best of luck, please keep us posted.

Andy Scott

Sounds like a reasonable approach, but then I wonder why they don't appear to have ever been done that way before? Maybe you can give it a try and report back?

You could also take a sheet metal angle and shrink it to the proper flange shape and then just fasten the joggled skins over the top.

You might want to buy Tim Bartons series of books "Metalshaping" - The Lost Sheet Metal Machines" #1-7, although only 1-4 have been published so far.

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Ordered! Can't wait to check these out. Looks like lots of good info for doing cowlings and fairings. I also have some interest in doing an aluminum car, so the info will cross over big-time.




I think I will try a section this way before I go through all the trouble of stretch forming. I'm fairly certain the results will be the same either way. I'll be back with an update once I've read Barton's books and smacked some aluminum around.