Sopwith Baby Project - Page 13

Nick · 9 February 2008, 02:25 AM

Quote:

Nick and Joe:
Any preferences for capstrip and 3-ply suppliers (A/C Spruce, Wicks, other?)?

Have bought stuff from both of them & both excellent to deal with. The main issue with the ply is who has got the size you want. The Snipe has an oddball size for the main rib ply of 3/20" which equates to 3.81mm so I ended up using a 4mm ply from a local supplier.

Joe
What size ply does the Baby have for the main Ribs? Is it a more readily available size?

Nick

Joe Perkel · 9 February 2008, 03:01 AM

Quote:

Originally Posted by Nick

Joe
What size ply does the Baby have for the main Ribs? Is it a more readily available size?

Nick

Nick,

I guess I got lucky there,...3/16" easy enough, they have in stock.

Took a quick peek at Spar stock (Wicks) and shipment issues. It seems that 10' and 14' lengths are available via special shipping. Outboard wing panels for me are 121.625" (10.135').

So how do I deal with that silly little .0135",...buy 14' and cut back to that 10.135' or splice two short pieces that can be shipped UPS???

drrivah · 9 February 2008, 05:38 AM

RE: Post #114 on original Sop Snipe and Dolphin wing and A& P 121 trailing edge discussion, wing details (lower left mainplane near wing root, both) of Pup replica (San Diego ASM) below. Leading edge nosing left intact, and trailing edge oval rather than tear drop section. Relevant detail from original Pup plans below. Was nosing lightened on all original Sop leading edges, and were original trailers always A & P 121 on Sop main planes?

-pete

Joe Perkel · 9 February 2008, 06:56 AM

Quote:

Originally Posted by drrivah

RE: Post #114 on original Sop Snipe and Dolphin wing and A& P 121 trailing edge discussion, wing details (lower left mainplane near wing root, both) of Pup replica (San Diego ASM) below. Leading edge nosing left intact, and trailing edge oval rather than tear drop section. Relevant detail from original Pup plans below. Was nosing lightened on all original Sop leading edges, and were original trailers always A & P 121 on Sop main planes?

-pete

Pete,

Nice images!

I have Pup and Strutter plans for reference. Have noted that the nosing is the same for the Baby & Pup but did not yet look at the Strutter.

Have also noted that both specify the A&P 121 section, including the wingtip and center section bows?! This is causing me a bit of confusion as to how to proceed.

Options appear to be,...

- similar tubing as close to original as possible?!

- Off the shelf trailing edge solutions?!

- laminated wooden bows with off the shelf trailing edge?!

Addendum to post: Looking at the Strutter in France, I see the wingtip bow is round tubing (steel). Not being home, I now recall the ends of both spars on the Baby accept 1/2" round tubing.

Nieuport pilot · 10 February 2008, 06:58 AM

I have tried to make the AP 121 trailing edge using rollers. I didn't have much luck as the tube wants to twist and bend as it passes thru. Without spendin alot of time making a bunch of rollers in a row to handle this I have decided to just take 3/8 x .035 mild steel tube and cruch itto 1/4. I am using it on my Pup and Hantiot Hd.1 projects and by the time you cover the parts it should look fine.
Rick Bennett

drrivah · 10 February 2008, 07:22 AM

Hi Joe: 1/2" x 0.035 round 4130 seems to be specified on many light homebuilts for wing tip bows. I have seen trailing edge (tubes) fitted to ribs with copper strip fittings, and the Jenny seems to have lots of copper (vs steel) fittings on empennage. Not sure how copper compares with steel or why one vs the other.

Hi Rick, how much difference in aerodynamic drag when trailing edge is A & P 121 vs 1/4 to 1/2 round or oval tube? Also, if you crush tubing or roll it, do people generally magnaflux to check on integrity of the reformed pieces? There must be some technical trick to rolling long lengths of A & P 121 without the twisting you mention. I recall Achim keeps the tubing in tension as it pulls, rather than rolling it out with the rolled end free. Did your trials keep the tube in tension or was the rolled end free?

Thanks.

-pete

Nieuport pilot · 10 February 2008, 07:41 AM

The larger the trailing edge the more drag. How much, I don't know. My Nieuport uses 1/2 trailing edged and it flies fine. All these WW1 types have LOTS of drag anyway.
When I tried to form the AP121 I just cranked it thru the one set of rollers. Sometimes it would come out ok for a foot or so and then twist. Since one side of the tube is larger than the other side it just doesn't want to stay straight. I am sure I could have solved the problem by adding more rollers but decided I didn't want to spend the time.
To me a 90 percent perfect machine flying five years sooner is more important. Someone else may want to spend the time. I love to build but also fly and am not getting any younger.
No need to check mild steel for cracking but 4130 can be a problem if bent too sharply. There was No 4130 in any original WW1 type so why bother for parts like this.
Rick Bennett

Joe Perkel · 10 February 2008, 09:28 AM

Quote:

Originally Posted by Nieuport pilot

I have decided to just take 3/8 x .035 mild steel tube and cruch itto 1/4. I am using it on my Pup and Hantiot Hd.1 projects and by the time you cover the parts it should look fine.

Rick Bennett

Aha...a reasonable solution,.. I knew there would be someone with one!

I don't recall who's tubing smasher jig I saw on the Dawn Patrol site, (perhaps yours Rick), but I suspect this is the best likely solution here to stay closer to authentic. A bit of work but, that's ok with me.

Thanks Rick, Pete!

baldeagle · 10 February 2008, 10:21 AM

I made some oval tubing for the trailing edges of the ailerons on my 1926 Ryan by welding a ring to the end of the tubing, and pulling it through rollers with a come-a-long hooked to a pickup truck. Kind of crude, but it worked OK. Don't remember the size of the tubing, probably 1/2" or 3/8" by .035".

Joe Perkel · 10 February 2008, 01:04 PM

Quote:

Originally Posted by baldeagle

I made some oval tubing for the trailing edges of the ailerons on my 1926 Ryan by welding a ring to the end of the tubing, and pulling it through rollers with a come-a-long hooked to a pickup truck. Kind of crude, but it worked OK. Don't remember the size of the tubing, probably 1/2" or 3/8" by .035".

Yet another entirely clever idea! Will have to test this and see what results,..thanks Andrew!

Thanks to all who responded to my initial confusion over the A&P Section, and the trailing edge in general. Now sufficiently confident to move on with the CAD model of the wing structures with the original A&P profile, knowing fully well construction solutions are there.