Sopwith Corner

nomma · 2 February 2005, 10:38 AM

Hi all,

I haven't seen a common thread for all of us building Sopwith aircraft. So here it is. I hope that we are able to share experiences, successes and mistakes...

I am building a Pup myself. I started planning last summer, so I am still in the very early phases. I have routed out the rib webs, done the capstrips, glued and routed the wing spars, have produced CAD of almost all metal fittings (THAT was a project in itself...) and I am currently figuring out how to produce the leading edges (or "nosings" as they are called).

The nosings have a "knob" or "heel" (I don't know the proper English word for it) for each rib. The capstrips are glued and screwed to this. I have attached some pics of it. My plan is to cut these "heels" first, by making a box jig and use a router with a ball bearing bit. Then use another jig to cut out the "gaps" for the capstrips, and finally a third jig to cut the straight edges of the top and bottom sides. After assembling the wing my idea is to use a small planer to round the leading edge.

Is there a better or simpler way to do this? The third photo shows the top and bottom parts of the box jig for the "heels".

Best regards,

Magnus Lord, Sweden

nomma · 4 February 2005, 01:33 AM

I am almost ready with the CAD drawings. The Sopwith people really knew how to complicate things

. Not one straight 90 degree bend... The clip CADs look like you have misread most of the dimensions...

This is the clip that sits on the bottom rear wing spar, holding the interplane wing strut and the internal and external wing bracing. The strut socket will be welded on top of this clip. Also there will be a doubler lug for the bent bracket holding the bracing, which is both riveted and welded. I heard that they had had some bad experience with welding, and didn't trust it entirely, so they used both riveting and welding together. Anyone heard this too?

NEW: Changed CAD to a better one. This is a wing spar box. The second pic shows the flat pattern that is used for laser cutting.

I think I may have shown CAD drawings before. Well, it's better than nothing...

I am using Solid Works' sheet metal function.

Brad · 4 February 2005, 07:10 AM

Nomma,

I have some pictures from the San Diego Aerospace Museum of their Pup- it is in the "lobby" area, uncovered. If you would like I could send them to you on CD. (They're too big to post!) Send me a private msg on the forum if you want them. I already have to make a copy for another guy, but I've been too busy to get it done- it won't be a big deal to just burn another CD.

I took them with a "disposable" camera, so they aren't the best quality, but some of them might be useful or interesting.

(I didn't forget, Gregory- I just haven't had time to do this at home yet!)

Brad

nomma · 4 February 2005, 10:08 AM

Thanks a lot, Brad!

Very generous of you! I'll post you a private message.

Best regards,

Magnus

wolfenbill · 4 February 2005, 12:51 PM

Do you have a router table? It seems that such a table would be ideal to cut that forward radius. It would take a few passes but it shouldn't be too big of a problem. I have looked at this part before and imagined a few ways to make it. You seem to be on the right track. Wish I could be there to help you solve this problem.

nomma · 4 February 2005, 02:18 PM

Wolfenbill,

Thanks for your advice! Yes I have a plunge router (my old one gave up last week, so I bought myself a new DeWalt, which I am looking forward to use) with a router table. I also have access to a larger spindle moulder, which I use for the spars. I have a friend who produces the cutters from my CAD files, which is very convenient.

I cannot use the moulder cutters for the knobs of the leading edge though. The radius is too large. So I plan to use the plunge router in the table, with a router bit with the ball bearing at the bottom instead of the top. I hope this will make the jigs simpler and the setup more stable.

The new router bit will hopefully arrive next week. I'll let you know how it works, of course.

Best regards,

Magnus

kitfoxdave · 4 February 2005, 04:52 PM

I also have about 20 picks I took of the Naked PUP with a disposable camera at the San Diego museum...Let me know and I will get them scanned and try to post them for you.

Great project!

I had been thinking maybe steel tube fuselage to avoid all the turnbuckles!
(and improve crashworthiness)

Dave

nomma · 4 February 2005, 11:34 PM

Dave,

Thank you very much! I have five different email addresses with a 5 MB limit each, so if they are less than 25 MB it's ok to email them.

Your question on the steel frame is interesting - it is all about what your goal is. Originally when I started thinking about this project, I just wanted to build a Pup-like aircraft with a fixed engine, to be able to fly a lot. But while studying the aircraft and history, I changed goal and I am now building as "authentic" as I can. It means that I will try to use the correct material everywhere, use a LeRhone, buy or produce the correct instruments etc. It makes it harder and very much more time consuming (mostly research), but great fun too.

I will however use some modern production methods like CAD, laser cutting, etc.

Best regards,

Magnus

kitfoxdave · 5 February 2005, 05:35 AM

I will try to get them all into a Yahoo photo album in the next few days and send you the link....

I would like to build one to fly a lot. The prospect of overhauls every 50 hours or so is not what I am looking for...
It is a really neat airplane, I saw my first replica at Rhinebeck when I was about 12 years old. I still have the Program from the show!

3-d cad is a godsend on a project like this. you can solve most problems without wasting material.

Good luck with the project.

Dave

nomma · 9 February 2005, 12:13 PM

Thank you very much for the pictures Dave! Interesting to see!

You have to enjoy the small things of life, don't you. Today all the screws I ordered from Ryder's of Bury, UK, arrived. They had found several old boxes of brass screws in their basement, which they now donated to the Pup project. Thanks a lot, Ryder's! The boxes look really great. Almost a pity to break the seals...

I have now invested in a used spindle moulder of my own, which will arrive this week. Looking forward to start working on the spars and struts again.

I have also produced a simple steam box to start steaming and shaping the capstrips for the ribs. I have no idea whether it will work. We will see...

Best regards,