How do you make a fuselage frame?

Strange question, but how do you make a curved fuselage frame, as fitted to an Avro Lancaster or whatever? I appreciate than huge presses were employed in mass production, but what if you only required one or two?

Large presses were less used than one might imagine….as all the responses illustrate forming sheet metal ‘frames’ was and is a hand skill (at most, semi-mechanised). Guillotining, folding, rolling, flange making byhammer or ‘flow-forming’ over exact patterns, curving with an ‘English Wheel’ did a lot of it.

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Form rollers 🙂

Yes, ok. But what about Lancaster frame E. In two parts, a L section which would be relatively easy. But what about the extrusion part with an open rectangular section. That’s really nasty.
Mike

You can check out this thread, http://warbirdinformationexchange.org/phpBB3/viewtopic.php?f=3&t=52024&sid=8550314fb6806a60c0d6b33568ac84f3, lots of excellent tin bending advise.

Many thanks for the excellent feedback! Another question relates to larger aircraft, such as the Halifax bomber; do these aircraft feature fuselage frames that are built in halves, then joined together, like the spitfire?

Phillip,
The Halifax formers are quite complicated in some areas such as the cockpit where frame 4/4a to 7 are made in several sections or split then Joined. in other areas the frames are similar in construction to the Spitfire. My drawings went to Canada so with luck new formers will be built.
Cheers
Cees

Being done at Tangmere, too.
http://www.tangmere-museum.org.uk/news/museums-spitfire-replica-cockpit
PP

Many thanks for the excellent feedback! Another question relates to larger aircraft, such as the Halifax bomber; do these aircraft feature fuselage frames that are built in halves, then joined together, like the spitfire?

Fuselage

Hello! Here is my GG Project! It was used in a TV fil called “Allied and alone ” about April 1940 when French , English , Polish and Norwegian forces tried to fight back germans in Northern Norway! best Jabba

Very nice video. And don’t forget the radiuses on the wooden jigs.
The drawings also indicate where the holes need to be drilled to bolt the
Metal blanks to the wooden jigs.
Cees

the you tube clip is excellent and thank you for sharing it. What I do on my frames is measure the frames from my blueprints onto a piece of ply/mdf and then use these screwed in 90degree angles that I got for making radio control aeroplane fuselages on large graph paper and then transpose these to make the jigs shape for the parts I am making. Cut out the parts for the ribs, or frames as appropriate and then screw/glue rivet them together to make the frame shape I want from that. Hopefullyif I have got the maths right I’ll end up with accurate frames.

There is a down and dirty way, which is measure and draw or even enlarge a photocopy of the frame drawing and stick it onto the wood/ metal and cut it out although accuracy might suffer as a result.

That Youtube clip posted by Oldspitty is exactly as it is done. If you were making frames for an airworthy project the metal would need heat treating following the shaping process but for a static build it could be left in the soft state.
The wooden forming blocks that each frame is formed around will obviously need to be different for each frame required but with modern CAD and laser technology this is less of an issue than it was.

Richard

Biggest issue is finding affordable accurate drawings

That Youtube clip posted by Oldspitty is exactly as it is done. If you were making frames for an airworthy project the metal would need heat treating following the shaping process but for a static build it could be left in the soft state.
The wooden forming blocks that each frame is formed around will obviously need to be different for each frame required but with modern CAD and laser technology this is less of an issue than it was.

Richard

Thats great, but it doesn’t answer the question.

Thinking it through

Strange question, but how do you make a curved fuselage frame, as fitted to an Avro Lancaster or whatever? I appreciate than huge presses were employed in mass production, but what if you only required one or two?

It is a question that in its naïveté opens up a range of fascinating possibilities. If I were tasked with creating in two weeks a decoy squadron of Lancasters with very little budget, that had to give off a metallic signature typical of a monocoque structure, that had to fool a secret agent that crawled under the wire and tapped the sides, what could I do? Given its 2015, I could in one day set up a 3D laser scanner and capture a real Lancaster 3 Dimensionally in a format that can be read by a Programmable machine. I would get a Pizza and place it and 5 litres of Coke next to a 22 year old CAD jockey and get them to slice the 3D object like a ham, then insert some cut outs to allow some standard rectangular section steel to be run the length and breadth of my sliced ham. I would then laser cut out of simple steel my slices of ham, buy a packet of cigarettes and get Trev the welder and his TA to weld the slices to the structural steel, to create a sliced ham, full sized 3D Lancaster, minus props. ( props are F28 bought on eBay as genuine WW2 Dambuster units). I would then wrap the sliced ham Lanc in foil, then fabric, then old carpet, then inject polyurethane foam into the cocoon, given that the CAD dude has made perforations in the slices to allow the void to fill. Once I remove the wrapping I would have a fully 3D Lanc that I could get some surfboard shapers to clean up the daggy bits. (I have now been called into dinner, so I have to pick this up later on)…

With a lot of hammering…Hopefully this explains it a bit.
https://www.youtube.com/watch?v=M7rXV4tdwvo

Maybe cast one if you have a pattern, or have one machined from solid billet?