What would your best guess be on the weight?
Sopwith Pup, 1/3 Scale by Balsa USA, Rescue
- Thread starter Joker 53150
- Start date
30-ish pounds all-up. Give or take a few.
So, those who do not know... Turnbuckles for a model this size are massively pricey. Think $5 a PIECE and you need one on every line... if you are going fully scale, you need one on BOTH ends of every line. On a WWI model like this you can easily spend $100 or more just on Turnbuckles.
Yeah, I was pricing all the components this morning and think I'll get them all from Balsa USA, even though there are a few choices that are about $1 cheaper per piece. And as mentioned previously, the rigging wires on this plane are absolutely required. Even just sitting on the ground in the pits waiting to fly, without the wires the wings would collapse.
The wings will need 12 turnbuckles total, plus another 4 at the center section of the wings, plus 2-4 more for the landing gear. So basically 20 pieces.
Plus the new wire, but decent wire is still fairly cheap at around $0.30/ft, and I'll end up using around 50' or so.
You can't simply tie the cable in a knot to fix the ends, and in my case I'll be using a Nicropress tool to crimp a sleeve over the ends. Another $52 for the crimping tool, some sleeves, and cable as a "starter pack".
One item I'm not looking forward to buying are "thimbles" for the ends. The thimble is kind of a loop that the cable goes through to keep from making a sharp bend at the end. These pieces are deceptively expensive at just over $1.10 per piece (expensive for how small they are, I guess). They are used at each end of a wire run, so each wire has 2. Figure close to $40 worth of these pieces. The problem with using them in this case is that they require a 1/8" hole. Most of the wire mounting locations are no problem, but there are 8 spots where two wires are very close together and that may cause clearance issues. Using them would require replacing some hard points, which wouldn't be a big deal.
So the short version of all that is that to re-do the rigging wires with turnbuckles and fancy compression sleeves on the ends will run me close to $200. However, 25% of that is for the tool to crimp the wire so I'll have that for future builds. (Look at me justify the price!
)
Most of the rigging wire ends right now are simple DuBro metal clevises. While plenty strong for a pushrod end, I don't have any warm & fuzzy feelings about trusting a 30 pound airplane to them, especially since it's very hard to see some of the ends to know if the pin is even clipped in place! They have some adjust-ability, but some pieces are bottomed-out and can't be tightened anymore.
The wings will need 12 turnbuckles total, plus another 4 at the center section of the wings, plus 2-4 more for the landing gear. So basically 20 pieces.
Plus the new wire, but decent wire is still fairly cheap at around $0.30/ft, and I'll end up using around 50' or so.
You can't simply tie the cable in a knot to fix the ends, and in my case I'll be using a Nicropress tool to crimp a sleeve over the ends. Another $52 for the crimping tool, some sleeves, and cable as a "starter pack".
One item I'm not looking forward to buying are "thimbles" for the ends. The thimble is kind of a loop that the cable goes through to keep from making a sharp bend at the end. These pieces are deceptively expensive at just over $1.10 per piece (expensive for how small they are, I guess). They are used at each end of a wire run, so each wire has 2. Figure close to $40 worth of these pieces. The problem with using them in this case is that they require a 1/8" hole. Most of the wire mounting locations are no problem, but there are 8 spots where two wires are very close together and that may cause clearance issues. Using them would require replacing some hard points, which wouldn't be a big deal.
So the short version of all that is that to re-do the rigging wires with turnbuckles and fancy compression sleeves on the ends will run me close to $200. However, 25% of that is for the tool to crimp the wire so I'll have that for future builds. (Look at me justify the price!
)Most of the rigging wire ends right now are simple DuBro metal clevises. While plenty strong for a pushrod end, I don't have any warm & fuzzy feelings about trusting a 30 pound airplane to them, especially since it's very hard to see some of the ends to know if the pin is even clipped in place! They have some adjust-ability, but some pieces are bottomed-out and can't be tightened anymore.
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Tench745
Master member
Personally, I would probably trust the clevises. You can always remove the wire and cut new threads to give you whatever adjustment you need. Way less expensive than re-rigging the whole thing. It would get you into the air anyway until you start in on the scale retrofit. Just my 2cents. She's a beaut!
Here's the issue with the clevises - they are all (currently) used on all 8 wires that support the full weight of the plane while in flight, while the rest of the wires are bolted at each end. If one or two fail I'm probably fine, unless they both fail at the same strut. This is a lot of plane capable of much damage in a crash, so this is insurance. They're of unknown vintage and with unknown wear & tear so I really don't want to trust the ends OR the wire and crimps. I could just replace them with the type of clevis already in use, but this is stronger, more adjustable, and is a great scale detail. Believe me, I'd MUCH rather spend the money on new covering for it, but the structure gets attention first, even if it keeps me from flying it this year. Here's what I really want to avoid - jump ahead to around the 1:37 mark...
Speaking of structure, I found a couple small problems with the "bones" of the plane. When moving the wing panels around I heard some rattling of balsa pieces in one of them. I'll do some inspecting to see if I can tell where it came from, hopefully it's just some minor damage. One of the wing tips for the upper wing is also a little loose and will be addressed. The tail group is also a little wobbly and should be taken care of before flight.
Speaking of structure, I found a couple small problems with the "bones" of the plane. When moving the wing panels around I heard some rattling of balsa pieces in one of them. I'll do some inspecting to see if I can tell where it came from, hopefully it's just some minor damage. One of the wing tips for the upper wing is also a little loose and will be addressed. The tail group is also a little wobbly and should be taken care of before flight.
Yeah, many thanks to the guys who design the stuff and make it available for free!
Amen to that. I talked with a guy this morning after a swap meet, who has built or re-built 4 of the big Pups, and the first thing he said was "replace those wires with turnbuckles!" There were a number of other recommendations, but from his experience any slack can be deadly, and he also told me about a couple other cables which should be required, like the "X" bracing at the ends of the wing struts. They're in the full-scale, but the kit shows them as optional. Evidently they help keep the lower wing from trying to pull out of the seat somehow. Again, cheap-ish insurance. It sounds like my 50cc Quadra will work alright, although it's on the lower end of power recommendations.
It's nice to learn a lot of the tips from somebody who's experienced it!
Nice work with the weathering/shading!
I removed the prop and cowl to gain access to the carb and fuel lines. The cowl was held on by about 25 screws around the perimeter or the cowl, and unfortunately they are not evenly spaced so it would drive a scale enthusiast nuts! (Willsonman) The carb came off easily, and when I turned it to more easily cut the gas line, the line cracked and fell off. Yeah, it's been on there for a few years...!
With the carb off I took it to my shop and found I had the right gaskets on-hand to rebuild it, so that task is out of the way. The plug looks good, but I ordered replacements to be safe. Since both Quadra 50s I have are equipped with the same plug and carb, I ordered a couple rebuild kits and plugs. The carb rebuild kit I use covers a lot of different Walbro carbs so they'll get used eventually. Quadra-specific parts like gaskets are in thin supply, but it looks like B&B Specialties in Indiana still has them available, so I'll order new gaskets for the engine while they're available, especially the intake and exhaust gaskets. The ones currently installed *might* be good, but gaskets are cheap and I don't want to take it apart again.
As it sits right now, if I had enough fuel line I could plumb it and have it ready to run fairly quickly. With work travel coming up in a few days it'll be next week before I get time to really go through it. The gas tank needs to be pulled along with the old gas lines so I can re-do the clunk hose and install a new bung in the tank. Can't wait to see this engine cough to life again!
With the carb off I took it to my shop and found I had the right gaskets on-hand to rebuild it, so that task is out of the way. The plug looks good, but I ordered replacements to be safe. Since both Quadra 50s I have are equipped with the same plug and carb, I ordered a couple rebuild kits and plugs. The carb rebuild kit I use covers a lot of different Walbro carbs so they'll get used eventually. Quadra-specific parts like gaskets are in thin supply, but it looks like B&B Specialties in Indiana still has them available, so I'll order new gaskets for the engine while they're available, especially the intake and exhaust gaskets. The ones currently installed *might* be good, but gaskets are cheap and I don't want to take it apart again.
As it sits right now, if I had enough fuel line I could plumb it and have it ready to run fairly quickly. With work travel coming up in a few days it'll be next week before I get time to really go through it. The gas tank needs to be pulled along with the old gas lines so I can re-do the clunk hose and install a new bung in the tank. Can't wait to see this engine cough to life again!
My club president recently picked up a 50' roll of tygon fuel tubing off amazon for around $50. HHe is pretty much set for the rest of his life.
While the Quadras are on the heavy side for their power, they are very reliable engines and worth every effort to prolong their life. I appreciate the care given and thorough explanation of the process you are going over.
While the Quadras are on the heavy side for their power, they are very reliable engines and worth every effort to prolong their life. I appreciate the care given and thorough explanation of the process you are going over.
A 50' roll would be a great thing to have. I've been buying the shorter 3' sections from Tower as-needed, but a big roll should be in my future. Those 3' pieces get used up fairly quickly by the time you run the main feed line, a vent line, and a fill line (if a separate one is used). The 1/4 scale Cub I'm working on used up about 2-1/2' with a simple 2-line system. About a foot of that was just to make sure there was enough slack to be able to get the tank out without disconnecting it at the engine. The Sopwith Pup will probably need 3 or 4 feet of line total. Most of what I use is the 1/8" ID, although I keep a package of the two smaller sizes just in case.
While the carb and plug were removed yesterday I shined some light down into the cylinder on the Quadra. The top of the piston has some minor discoloring from use, and the side of the piston (as seen through the intake port) is very shiny and bright. No scuffing was noticed at all, so I'm very optimistic about the condition of this engine as it appears to have minimal time on it. The outside is fairly dusty from age, but that doesn't concern me. While the plug was out I trickled in about 1/2 teaspoon of Marvel Mystery Oil to make sure the top end is well lubed prior to spin-starting it. It has very good compression, but I'm worried about there being any crud in there, and the detergent properties of the MMO should help.
While the carb and plug were removed yesterday I shined some light down into the cylinder on the Quadra. The top of the piston has some minor discoloring from use, and the side of the piston (as seen through the intake port) is very shiny and bright. No scuffing was noticed at all, so I'm very optimistic about the condition of this engine as it appears to have minimal time on it. The outside is fairly dusty from age, but that doesn't concern me. While the plug was out I trickled in about 1/2 teaspoon of Marvel Mystery Oil to make sure the top end is well lubed prior to spin-starting it. It has very good compression, but I'm worried about there being any crud in there, and the detergent properties of the MMO should help.
Seafoam?
Nope, Marvel Mystery Oil. You're not familiar with it? It's a lightweight oil with some detergent properties. Some people add it to the crankcase oil in cars to help break up sludge on older engines, although I'd be too worried about blocking oil passages. My main use over the years has been using it to coat cylinders on motorcycles or snowmobiles when I'm putting them away for the season. Pour a small amount into each cylinder and crank the engine to coat everything. There is a cult following for MMO.
I used Seafoam on a few vehicles in the past, adding it to the fuel tank to help clean the system. No idea if it actually did anything, though.
I used Seafoam on a few vehicles in the past, adding it to the fuel tank to help clean the system. No idea if it actually did anything, though.
IT LIVES!! Wow, I really needed a nice victory like this, as the last few weeks have been terrible.
I'll fully admit that how I've got it set up right now is not super-safe, but before spending any real time on it I wanted to see what I'm up against. The throttle servo is shot, and the old fuel tank and lines still need to be removed. For now I just used industrial-grade adhesive material (blue tape) to hold the tank on top of the cowl and threw a quick string between the wheels to keep them from vibrating off (they aren't secured in place yet). Sketchy? You bet!
So a little gas was added to the tank, a new line run, and I flipped the prop a few times to prime the carb. Aaaaaaand.... nothing. No suction at all, and no spark of life. I force-fed it a little gas and got a quick burp of life, so there was a glimmer of hope. More flipping, no suction, much swearing. A little more gas and I saw it leaking between the carb and engine, so it's probably an air leak.
I have two of these Quadras, but no new gaskets (they're hard to find) so I grabbed the other engine and removed the carb gaskets which are also kind of dried out and cruddy. Doubling them up on the engine seemed to do the trick and I was able to get a little suction, eventually enough to get gas into the carb.
A few flips of the prop later and.....
I know it runs, so now I just need to make it run "right". It needs new gaskets for the carb isolator so I'll probably end up going to the auto-parts store and getting a roll of gasket material so I can cut my own. I'll also replace the throttle servo so it's easier to test. The prop hasn't been balanced for a decade or so, and that'll be done as well. These test runs were all done at less than 1/3 throttle, and I'll probably run it like that for a few more ounces of gas just to make sure it's running properly.
Dang, I'm a bit giddy now!
Wow, I really needed a nice victory like this, as the last few weeks have been terrible.I'll fully admit that how I've got it set up right now is not super-safe, but before spending any real time on it I wanted to see what I'm up against. The throttle servo is shot, and the old fuel tank and lines still need to be removed. For now I just used industrial-grade adhesive material (blue tape) to hold the tank on top of the cowl and threw a quick string between the wheels to keep them from vibrating off (they aren't secured in place yet). Sketchy? You bet!
So a little gas was added to the tank, a new line run, and I flipped the prop a few times to prime the carb. Aaaaaaand.... nothing. No suction at all, and no spark of life. I force-fed it a little gas and got a quick burp of life, so there was a glimmer of hope. More flipping, no suction, much swearing. A little more gas and I saw it leaking between the carb and engine, so it's probably an air leak.
I have two of these Quadras, but no new gaskets (they're hard to find) so I grabbed the other engine and removed the carb gaskets which are also kind of dried out and cruddy. Doubling them up on the engine seemed to do the trick and I was able to get a little suction, eventually enough to get gas into the carb.
A few flips of the prop later and.....
I know it runs, so now I just need to make it run "right". It needs new gaskets for the carb isolator so I'll probably end up going to the auto-parts store and getting a roll of gasket material so I can cut my own. I'll also replace the throttle servo so it's easier to test. The prop hasn't been balanced for a decade or so, and that'll be done as well. These test runs were all done at less than 1/3 throttle, and I'll probably run it like that for a few more ounces of gas just to make sure it's running properly.
Dang, I'm a bit giddy now!
Every time I walk through the garage I see the Pup, and it bugs me that I haven't done anything with it yet. I'm trying to be realistic, and now figure there is zero chance of it flying this year as there are simply too many other projects ahead of it.
- My Balsa USA 1/4 scale Cub needs some final touches (only a few hours work).
- The Mountain Models EVA Bipe needs to be finished so it can be taken to Flite Fest.
- The Sig Kadet Senior is almost ready for electronics and covering.
- The Sig 1/4 scale Cub needs some engine tuning.
- My 1/4 scale Pietenpol needs windscreens and a pilot, plus I need to troubleshoot some bad flight performance last time it was out.
- The 1/4 scale Citabria needs a gas engine installed to replace the nitro.
But in the meantime, I'm collecting parts for the Pup. As mentioned very early in this thread, turnbuckles for the flying wires are expensive, and I'll need about 24-28 of them. Every time I have a chance to run past the not-so-local hobby shop I stop in and grab a 2-pack of DuBro turnbuckles. I think I've got 8 or 10 of them now...! I also found a guy on Ebay selling newly printed plans for this kit. I do have the original plans the plane was built from, but they're beat up and pretty rough. The new plans were fairly cheap and came rolled, so no fold lines to deal with.
So soon I'll just bite the bullet and clear room in the basement workshop for the Pup to reside until it gets to the front of the line. Making room for a plane this size is going to be an interesting project!
- My Balsa USA 1/4 scale Cub needs some final touches (only a few hours work).
- The Mountain Models EVA Bipe needs to be finished so it can be taken to Flite Fest.
- The Sig Kadet Senior is almost ready for electronics and covering.
- The Sig 1/4 scale Cub needs some engine tuning.
- My 1/4 scale Pietenpol needs windscreens and a pilot, plus I need to troubleshoot some bad flight performance last time it was out.
- The 1/4 scale Citabria needs a gas engine installed to replace the nitro.
But in the meantime, I'm collecting parts for the Pup. As mentioned very early in this thread, turnbuckles for the flying wires are expensive, and I'll need about 24-28 of them. Every time I have a chance to run past the not-so-local hobby shop I stop in and grab a 2-pack of DuBro turnbuckles. I think I've got 8 or 10 of them now...! I also found a guy on Ebay selling newly printed plans for this kit. I do have the original plans the plane was built from, but they're beat up and pretty rough. The new plans were fairly cheap and came rolled, so no fold lines to deal with.
So soon I'll just bite the bullet and clear room in the basement workshop for the Pup to reside until it gets to the front of the line. Making room for a plane this size is going to be an interesting project!
