Restoring a 15 yr old BUSA 1/3 Sopwith Pup  
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Restoring a 15 yr old BUSA 1/3 Sopwith Pup - 6/17/2007 9:31:55 PM   
splais


 

Posts: 2746
Joined: 12/12/2001
From: Yuma, AZ, USA
Status: online 		I’m not a builder, I’m old (almost), and my hands shake when I try to do detail. I’m a screw driver and hammer kind of guy. That being said, I am starting this thread , and will continue it as things progress, documenting my restoration of a 15 year old BUSA 1/3 scale Sopwith Pup. It really starts on post #8 as I started this under another name. Please keep in mind I’m not unhappy with what I write below: it just would have been nice to have been in better condition. Hopefully there is something in here worth reading.


I'm starting to get in over my head - I also still haven't learned that you don't move anything on these big birds without doing it slowing and seeing everything in the way.

Anyway, as you can see I have broken the front edge off a wood control horn on a 15 year old Pup I have been trying to get flight ready. This is the bottom horn on a pull-pull system and the horn is built into the elevator. Before I ask about some of my thoughts; I'm open to suggestions on the best way to repair this. I guess a picture is worth at least three paragraphs of description.

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< Message edited by splais -- 7/28/2007 4:19:26 AM >
       Post #: 1

RE: Help Repairing Elevator Control Horn - 6/17/2007 9:44:02 PM   
abufletcher



Posts: 5556
Joined: 2/13/2004
From: Zentsuji, JAPAN
Status: offline 		Splais, first you really should start a "restoration thread" for your Pup so that you can keep all your questions and the suggested solutions in one convenient place.

As far as this problem, I'd strongly suggest replacing all the wooden horns with ones made either of metal or circuit board material. BTW, it's much better that this has happened now than up in the air! In the photo it looks like very weak ply with just a couple of veniers and a crumbly center vs. a good multi-layer aircraft ply.

< Message edited by abufletcher -- 6/17/2007 10:13:10 PM >

(in reply to splais)
       Post #: 2

RE: Help Repairing Elevator Control Horn - 6/17/2007 11:01:15 PM   
splais


 

Posts: 2746
Joined: 12/12/2001
From: Yuma, AZ, USA
Status: online 		You may be right about the thread; I'll think about it, but being a novice at this building and repairing not sure how valid it would be.

The horns are made out of whatever came in a 15 year old BUSA kit. This "RTF" Pup I purchased has turned into a major rebuild - the thing was a wreck! But thats for another story.

This picture is of the good control horn on the other elevator. You can see how it is sandwiched into the elevator structure. I know the kind of horns you are talking about.

Is replacing these horns something I can do with the elevator attached? Also, if you have the time, could you step me through the process? Is it as simple as just cutting the old horn out and epoxying a new horn in, or is there more to it than that? The sad part is I just finished regluing the nylon pinned hinges that were coming out, last week. I do not think I can get the pins out without damaging the elevator.

PS: I do not like the cable to horn angle you can see there, either.

Steve



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< Message edited by splais -- 6/17/2007 11:02:08 PM >

(in reply to abufletcher)
       Post #: 3

RE: Help Repairing Elevator Control Horn - 6/18/2007 1:17:07 PM   
camdyson



Posts: 842
Joined: 7/20/2005
From: Bairnsdale, AUSTRALIA
Status: offline 		Hi Steve,

YIKES!! I hate to be a killjoy, but I'd start by cutting ALL your existing elevator horns off flush, and start again (rebuilding the result of a crash takes alot longer... )

You need to use quality aircraft ply, or better yet carbon, steel or circuit board as Don says. you can restore the "old" look to these materials by addind a veneer of 1mm ply on the outsides. I'd be inclined to cut back the covering around the existing horns and check what you're gluing to, then patch around the new horns, hiding the old stumps at the same time.

Oh, shim them parrallel to the clevis too!

Man, you must have the patience of a saint with this thing!

Cheers,

Cam

(in reply to splais)
       Post #: 4

RE: Help Repairing Elevator Control Horn - 6/18/2007 2:10:58 PM   
abufletcher



Posts: 5556
Joined: 2/13/2004
From: Zentsuji, JAPAN
Status: offline
quote:

ORIGINAL: camdyson
you can restore the "old" look to these materials by addind a veneer of 1mm ply on the outsides.


But there's really no need for that since the control horns were metal on the original anyway. Seriously, if all the control horns on all the surfaces are like this they ALL need to be replaced.

(in reply to camdyson)
       Post #: 5

RE: Help Repairing Elevator Control Horn - 6/18/2007 3:33:29 PM   
abufletcher



Posts: 5556
Joined: 2/13/2004
From: Zentsuji, JAPAN
Status: offline 		I've been looking at that first photo again and I looks like the control horn is in the wrong position. The attachment point (i.e. the pivot point) looks like it's well behind the hinge line.

The second photo looks ok though.

(in reply to abufletcher)
       Post #: 6

RE: Help Repairing Elevator Control Horn - 6/18/2007 11:22:48 PM   
BobH


 

Posts: 4423
Joined: 4/1/2003
From: Springfield, VA,
Status: offline 		I might be tempted to glue the broken part back on and then sandwich the entire affair betweem some G-10 of a decent thickness.. say 0.030 or so. If you epoxy the G-10 to both sides of the broken part I believe it will be plenty strong enough. Do the same thing for the other side of the elevator so you have a matched set.

_____________________________

BobH.

(in reply to splais)
       Post #: 7

RE: Help Repairing Elevator Control Horn - 6/18/2007 11:53:20 PM   
splais


 

Posts: 2746
Joined: 12/12/2001
From: Yuma, AZ, USA
Status: online 		I actually thought about just cutting them all off a little and drilling new holes. the plane only needs a 1/2" of throw according to manual. But that doesn't solve the bad angle issue. But then I came up with a fix for that. But then I thought this might be a good time to learn how to replace a control horn if I really want to be a "restorer" Besides, as noted, the "Ackerman" on the elevators is all messed up

< Message edited by splais -- 6/19/2007 12:09:46 AM >

(in reply to BobH)
       Post #: 8

RE: Help Repairing Elevator Control Horn - 6/18/2007 11:54:57 PM   
splais


 

Posts: 2746
Joined: 12/12/2001
From: Yuma, AZ, USA
Status: online 		This project has taken several turns before reaching it’s present point. First I was just going to fly her and see how she did before deciding how far to go with an upgrade. Then after looking her over I thought about a entire strip-off and rebuild in my favorite Pup’s colors and all the scale upgrades I could afford. Then after trying to get her flight ready I almost decided to throw it away and take on another project. Now I’ve compromised into something between doing just as little as possible and something a bit more.

This plane was purchased long distance, site unseen (except pictures), in RTF condition (supposedly); equipped with a spring-start G62 (stock muffler) and Airtronics electronics with some sort of ancient Japanese smoke system installed. Weight is 31 pounds. Hasn’t been flown in four or five years according to seller.

The plane was basically BUSA stock with no strut “X” supports, undercarriage supports and only a minor dash upgrade. Pull-pull on elevator and rudder, wing root mounted aileron servos per BUSA plans. BUSA wing wires with brass turnbuckles. The Vickers gun was a very unscale add-on. All wing linkages and servos were installed “under” the covering with no access panels provided.

Forget adding scale touches at this time; while I had expected to do a lot of work; this plane was/is not airworthy and is taking a major overhaul just to get it that way. The following is what I had to start with:

- Covering in poor condition with many patches, small unpatched holes and paint cracking on all roundals
- One turnbuckle broken and three others in the process of breaking.
- Cracked firewall.
- Missing cowl mounting block.
- Broken smoke fuel line.
- Gas tank falling apart.
- 15 year old out of date airtronics servos (not an issue, was going to replace anyway).
- Elevator hinges falling out on both sides.
- Stock wire wheels falling apart.
- Undercarriage wood stuts coming apart.
- Pull-pull systems worn out.

To date I have:

- Replaced all electronics and re-plumbed the fuel and smoke systems.
- Re-hinged the elevator.
- Repaired cracked firewall.
- Installed Aces of Iron pilot.
- Installed undercarriage and wing strut support wires.
- Repaired worn/damaged pull-pull setup.
- Patched and painted several holes.
- Replaced the wheels with painted Dubro Vintage Wheels.

Still to do:

- Replace all flying and landing wires.
- Replace elevator control horns.
- One additional, still unresolved problem – excessive slop in aileron bellcrank linkage system that is not caused by the servo.

Now for the good part. Started the engine up this past weekend fairly easily and she seems to be running just fine.

Restoration on hold waiting for parts on order…:

- 1/3 scale Vickers gun kit.
- Flying wire, control horns and misc small parts from Proctor and Reeves.

Pictures coming shortly...


< Message edited by splais -- 6/19/2007 2:37:16 PM >

(in reply to splais)
       Post #: 9

RE: Help Repairing Elevator Control Horn - 6/19/2007 12:25:01 AM   
abufletcher



Posts: 5556
Joined: 2/13/2004
From: Zentsuji, JAPAN
Status: offline 		I'd definitely take a "get 'er done" attitude and only do what you need to get the model into the air. Don't bother with any fancy scale stuff until you know you have a flightworthy model.

I'm not sure that just glueing some layers of G-10 material on the sides would work since the horn could still snap off at the base given the age and poor quality or the ply. But you could cut through the elevator on one (or both) side and slip the new horn in next to the old ones.

But really, I'd just replace them completely. Replacing horns is a pretty basic repair and shouldn't be any challenge. Just cut out the old and glue in the new. Then add a fabric patch.

BTW, there's really no reason to BUY control horns -- they are so easy to make.

(in reply to splais)
       Post #: 10

RE: Help Repairing Elevator Control Horn - 6/19/2007 11:34:14 AM   
Frank Sopwith



Posts: 118
Joined: 1/20/2007
From: Westervoort, NETHERLANDS
Status: offline
quote:

ORIGINAL: abufletcher; But really, I'd just replace them completely. Replacing horns is a pretty basic repair and shouldn't be any challenge. Just cut out the old and glue in the new. Then add a fabric patch. BTW, there's really no reason to BUY control horns -- they are so easy to make.


I agree with Don (as an experienced BUSA pup flyer for many years) I would never use wooden control horns on a 31 Lbs plane!
Just use circuit board (Tufnol or Novotex to be precise) and replace them all, it is worth the job!

Frank


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BLue Skies Happy Landings

(in reply to abufletcher)
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RE: Help Repairing Elevator Control Horn - 6/19/2007 12:22:47 PM   
BobH


 

Posts: 4423
Joined: 4/1/2003
From: Springfield, VA,
Status: offline 		I didn't read that it was a 1/3 scale plane duh me! I'd rebuild things until they are correct as well. Makes sense if you plan to keep it and fly it.

_____________________________

BobH.

(in reply to Frank Sopwith)
       Post #: 12

RE: Help Repairing Elevator Control Horn - 6/19/2007 1:57:30 PM   
pettit



Posts: 2164
Joined: 12/19/2001
From: Durham, NC, USA
Status: offline 		I would definitely pull out the center aileron servo and associated bellcranks/pushrods and make arrangements for separate servos at each aileron.

Easy to add a servo plate and fish the wires through the ribs, maybe where the pushrods went.

No slop in that type of linkage, in respect to the "Rube Goldberg" bellcrank setup as shown on the antiquated plans.

_____________________________

Dick Pettit
Associate Editor, R/C REPORT Magazine
"You Can Buy Better,
But You Can't Pay More"

(in reply to BobH)
       Post #: 13

RE: Restoring a 1/3 Sopwith Pup(Repairing Elevator Con... - 6/19/2007 2:36:48 PM   
splais


 

Posts: 2746
Joined: 12/12/2001
From: Yuma, AZ, USA
Status: online 		I think all you guys are just sitting back giggling at all the work suggestions I have given up getting this bird in the air for at least a few more weeks while I learn how, and complete all these mods. My shop looks like an old time Sopwith factory out of WWI

Petit: I had used a mirror and cut a whole to look at that aileron setup. Can't for the life of me figure out why the plans didn't call for burying the servo out by the aileron. the suggested system is a mess. Maybe it had something to do with long electronic runs in servos back 15 years ago. Don't know if BUSA still suggest that; but installing this 90 degree angle double pushrod and bellcrank system; and then covering it all up with no access panels was not a good thing.

Bob/Abu: I experimented last night and found if I heat a #11 blade I can slide it right down through the epoxy. Removing the old horn appears to be relatively simple. My plane was build with the ability to remove the horizontal/vertcal stabilizer assembly, which will make working on the control horn easier. Since I just rehinged the thing a week ago, I'm going to try and remove/replace the elevator horns without detaching the control surface.

Anyone: the plane is covered with Antique Coverite. I'm having a problem getting the new material to stick to the old material when I'm patching, especially when it (the old) is painted. Any suggestions? Because I have used alcohol to clean the old surface, but that doesn't seem to help.

Steve

< Message edited by splais -- 6/19/2007 2:54:05 PM >

(in reply to pettit)