splais

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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.

abufletcher

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.

splais

My Feedback: (25)

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

camdyson

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

abufletcher

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.

abufletcher

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.

BobH

My Feedback: (2)

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.

splais

My Feedback: (25)

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 []

splais

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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...

abufletcher

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.

Frank Sopwith

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

BobH

My Feedback: (2)

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.

pettit

My Feedback: (23)

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.

splais

My Feedback: (25)

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

splais

My Feedback: (25)

I've decided to use this Pup as a training tool for all the things I've never done before in repairing a bird. I can always go back and start over again.

Below is a sequence of pictures for my elevator control horn repair.

Step 1: use a hot knife with #11 blade to cut out the old horn. Worked great on was a very clean remove on my second try on the other side.

Step 2: insert the new metal horn, position and make some wedges to hold it in place.
Step 3: Epoxy it in place.
Step 4: Cover and paint. It appears to be rock solid and now the angles are all OK.

As a side note, I tryed a test on the old broken horn. I CA'd the broken piece in place and put a layer of epoxy over it. I clamped the old horn in a vise and hooked a clevis up to it. Pulled on it with about 4x the force it would ever get flying and it did not break again.

abufletcher

Looks great!

splais

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I built my first aerodynamic flying wire. The first pic is of the mess I'm replacing. The last two pics is of the support wires I crafted for the undercarriage using Proctor cables and eyebolts. The wheel is a painted dubro vintage 9" wheel.

The flying wires have a Proctor #7 turnbuckle with Proctor flat flying wire soldered into the clevis end of the turnbuckle. The other end is soldered into a Proctor clevis end screwed into a Robart 2-56 clevis and then painted flat black.

BobH

My Feedback: (2)

Steve its good to see you have everything sorted out..

splais

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Yes, I'm learning a great deal - no matter how good I do I think I can do it way better next time - this stuff is harder than it looks and easier than you think.

splais

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Well after taking a look at my first attempt at flying wires it just wasn't good enough.

Pictured below is my new version I soldered the Proctor flat wire into a Dubro 1/4 scale clevis. It looks much better and much closer to scale fittings on the real Pup.

Phase I is nearing completion; but first test flight is delayed further. I found another bad wing wire so I'm going to redo them all before trying to fly this bird. I probably need to replace the aileron control horns also anyway.

eagledancer

i hope you used silver solder on those flying wires, not silver bearing solder or common soft solder.

splais

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When I get home tonight I'll tell you exactly what I used. I did intend to use SS; but because I'm new at this, who knows [X(]

splais

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To paraphrase - Houston, do I have a problem [] Keeping in mind that I haven't yet actually started the real wires, am I using the wrong solder? It is Benzomatic Metal Works silver bearing, lead free, acid core solder.

Thanks

splais

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Of Turnbuckles & Flying Wires – the secret passion of Ernest Hemingway

Sometimes it amazes me how wrapped up in you can get in one part of a planes construction. I’ve determined I need to replace the flying wires. Thought it would be easy, then I learned there was cable, flat wire, scale wire, turnbuckles, clevis’ safety wire, and on and on.

I’m using Proctor Flat Wire and the wires will be attached at each end by screws. What goes between the screws and the flat wire is the issue. Turnbuckles look neat but are not very scale. The real Pup had scale flying wires with clevis’ very similar to those in picture #4.

Picture #1 is of a Proctor turnbuckle that has the flat wire soldered to the clevis end. You will note that there is no way to properly install safety wire when this turnbuckle is mounted with a screw to the plane.

Picture #2 is a really cheap looking setup I came up with first using a Robart clevis and threaded Proctor turnbuckle end. As you can readily see, it looks like crap.

Pictures #3 & #4 are a new flying wire end I came up with using the Dubro ¼ scale HD clevis on the fixed end and adding a threaded rod end coupler. I’m also going to experiment with replacing the coupler with a 4-40 screw that has the flat wire soldered to the head. My concern with this idea is the strength of the connection. I am not real confident in my soldering yet and I’m thinking that if I trim down the coupler on both ends it will still be strong and look a lot more compact.

Picture #5 is the new better looking adjustable wire end.

Back to picture #1 for a moment. I can come up with no idea how to lock this turnbuckle in place other than using locktite and epoxy. I think I have decided on the "non-turnbickle" method for a more scale, hassle free look.

BobH

My Feedback: (2)

Steve the turnbuckle would be "locked" in place using safety wire to keep it from turning.