Sopwith Snipe Project

sheppo · 21 October 2009, 06:51 PM

Gday Nick

Did you use cerrabend or similar inside the tue during the bending operation?

Chris

Nick · 21 October 2009, 11:32 PM

Quote:

Originally Posted by Joe Perkel

Nick,

Any tendency for springback here?, If so was it much, or negligible?

I see the end result is that it took the form well for assembly, but wonder if it needed some persuasion. The top center section on the Baby, has two 3" radius bends that reverse direction on the same piece.

Beautiful results as always!

Quote:

Originally Posted by Sheppo

Gday Nick

Did you use cerrabend or similar inside the tue during the bending operation?

Chris

Hi Joe and Chris,
This stuff is much easier to bend than it would have been had we gone the 4130 route which would be a bit of a nightmare I’d think. I didn’t use any kind of filler and it hasn’t deformed. Just minor springback, easily coaxed into shape.
The bend radius on this is 4” inner or 4 ½” to the outer however the rudder was only 2” in a couple of places and took a bit more persuasion. Basically it’s easy to bend but it’s essential to keep the edge at right angles to the former.
I had a bit of trouble with my first go bending the rudder leading edge until I got the hang of it. It naturally just wants to twist and bend round the flat part so you have to have a way to stop that. There’s bound to be a better way but I found tacking the guide strips around the former worked and kept it edge on.

Cheers, Nick

ulpilot · 22 October 2009, 02:57 AM

Excellent workmanship! And I'm not saying that just because your using my tubing.

Nick · 23 October 2009, 01:50 PM

Quote:

Originally Posted by ulpilot

Excellent workmanship! And I'm not saying that just because your using my tubing.

Thanks Vet, much appreciated. I was wondering whether you may be able to suggest a better way to bend this as I still have the wings and Aileron trailing edge to bend up. Possibly a system of rollers maybe, but would need to be made to fit either side of the same streamline profile.

Cheers, Nick

ulpilot · 24 October 2009, 03:45 AM

Quote:

Originally Posted by Nick

Thanks Vet, much appreciated. I was wondering whether you may be able to suggest a better way to bend this as I still have the wings and Aileron trailing edge to bend up. Possibly a system of rollers maybe, but would need to be made to fit either side of the same streamline profile.

Cheers, Nick

I have an automotive brake line bending tool that works great on round tube. I think a couple of changes and it will work for the A&P tube. I'll post a picture tonight with an explanation.

Vet

ulpilot · 24 October 2009, 06:10 PM

Here is a picture of my brake line bending tool. With a little practice one can make bends of almost any radius. It would be easy to make one for bending A&P tubing.

First I would make the steel roll with to different grooves. First a "U" shaped groove that fits the wider side of the tubing. Then a second "V" groove to fit the backside of the tubing. This will allow bending the tube for both inside and outside curves. These should be deep enough to hold around half the width of the tube.

The upper cross piece should also have 2 grooves. A "U" groove inline with the "V" in the roll, and "U" inline with the rolls "V". This is what will hold the tubing from rolling over when bending.

Note that the cross piece is not directly over the center of the steel roll, but offset.

Another idea is in the pdf file I sent out with the tubing. Sandwich 3 plywood disks 1 slightly smaller than the others, to create a slot to hold the tube.

Hope this helps.

Nick · 24 October 2009, 11:44 PM

Many thanks Vet for posting that, much appreciated. That's a great help.

Cheers, Nick

Nick · 20 November 2009, 11:52 AM

Took Vet’s advice and made a former for bending out of 3 sheets of MDF as per the Tony Bingelis books, and that works a treat. I found for bending the 4 ½” radius if I bent it round the 4” it sprang back to about 4 ½”. The hole in the middle is for clamping it in the vice. I bought one of those pipe bender gadgets but it wasn’t quite strong enough and it bent the tool instead, but as Vet said, with a bit of modification it would be good for tweaking here and there.

Then started setting up the jig which needed holes for the control horns to go through. Made them a few months ago as are the same as the Rudder control horn.

Then pinning, brazing, welding all the various fittings and hinge stops

Then back to the jig to pin all the ribs in place before brazing them.

Once done, a clean up, then a prime and paint

Then hang on the wall until it’s time to assemble

Cheers, Nick

bristol scout · 20 November 2009, 12:17 PM

HI Nick,
I don't know why it has taken me this long to say it but this is workmanship of the very highest order---just utterly admirable----your love of this subject is self evident----people like you-- and John McKenzie (though we've had differences John and me!) are absolute incomparable masters.

Cheers,
Dave.

Nick · 20 November 2009, 07:08 PM

Hi Dave ,
Many thanks for your kind comments and much appreciated. I am in awe of the knowledge and work of both John McKenzie and of Koloman Mayrhofer. I’m nowhere near that league, but as a first time builder am learning all the time as I go. It’s certainly a good way to learn lots of new (old) skills.

Cheers, Nick