Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
#201
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
ORIGINAL: AmishWarlord
That's some really nice wood those ribs are made of. Sig did a good job in balsa selection there. Was this a older kit or is this a new production one?
That's some really nice wood those ribs are made of. Sig did a good job in balsa selection there. Was this a older kit or is this a new production one?
From the look of some of the wing ribs Sig should sharpen their die-cutters or convert the kit to laser cutting. Some of the ribs suffered some die-crunching. The ribs are die-cut, the wing tips are laser cut from ply, and many parts are ink printed and you get to cut them out. The fuselage is basically scratch building from sticks.
Sig is not kidding around when they call this kit a "Craftsman's Kit". It is a lot of work but with that I am getting a lot of satisfaction that it is coming together.
SunDevilPilot
#203
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
I started working on the laminations for the wing tips. Currently I have the laminated balsa installed on the right wing. I decided it would be best to pre-bend the wood to roughly the shape needed to make the process a little easier. I soaked the wood for about an hour in some hot water then wrapped it around a large metal pot. The pieces were strapped around the pot with a band clamp and left to dry over night. The results were some nicely pre-bent balsa, much easier to work with.
Next step is to install the leading edge material then I will jump over to the other wing and repeat the process. After that I will sheet the tips and begin the process of carving out the leading edge.
SunDevilPilot
Next step is to install the leading edge material then I will jump over to the other wing and repeat the process. After that I will sheet the tips and begin the process of carving out the leading edge.
SunDevilPilot
#205
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
The leading edge and the wing tip sheeting is installed on both wings. I have also started to rough shape the leading edge of one wing. The rough shaping was done with a 9 1/2" hand plane. I will get the leading edge close with the hand plane then finish the shaping with a sanding bar.
There is something refreshing about freshly planed shavings of wood!
I picked up a Lie Nielsen hand plane for this project. I have a hobby one, which is a joke compared to the Lie Nielsen. The plane takes off paper thin curls of balsa with ease.
SunDevilPilot
There is something refreshing about freshly planed shavings of wood!
I picked up a Lie Nielsen hand plane for this project. I have a hobby one, which is a joke compared to the Lie Nielsen. The plane takes off paper thin curls of balsa with ease.
SunDevilPilot
#206
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
That's exactly how I prepared the leading edges on my Cub wings.
Anything that I can hack, saw, slice, chop off or otherwise remove in big chunks is great because it makes the sanding that much quicker and easier.
My massive, 12" diameter rotary power sander is great for taking down blocks too, as on the nose. Just got to go easy.
Anything that I can hack, saw, slice, chop off or otherwise remove in big chunks is great because it makes the sanding that much quicker and easier.
My massive, 12" diameter rotary power sander is great for taking down blocks too, as on the nose. Just got to go easy.
#207
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RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
Dude, I gotta have one of those planes. I have the JOKE hobby plane that does more harm than good, so I end up sanding most of the L.E.
#209
Banned
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
ORIGINAL: roncannell
Dude, I gotta have one of those planes. I have the JOKE hobby plane that does more harm than good, so I end up sanding most of the L.E.
Dude, I gotta have one of those planes. I have the JOKE hobby plane that does more harm than good, so I end up sanding most of the L.E.
You have a sample with picture just a few posts away.
Zor
#210
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
ORIGINAL: roncannell
Holy Cow, nevermind, I googled the price, sorry Phil I will have to borrow yours.
Holy Cow, nevermind, I googled the price, sorry Phil I will have to borrow yours.
SunDevilPilot
#212
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
Wingtip sheeting and caps strips are complete. Next step is to shape the leading edge and the outer edge of the wingtips. Should not be too difficult, I just need to take my time as there is no way to put back the material once it is sanded off.
SunDevilPilot
SunDevilPilot
#213
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RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
Beautiful wing Phil. I just removed the covering off my GP Clipped wing. I decided to recover it to remove the weight the paint added. It was hard to tear off that $200 Nelson paint Job. and I always wanted a Hazel Sig Design. But it was just gonna be a hangar queen. So it probably will not look nearly as good but some garden variety Monocote should lighten up. I may splurge for some Solortex.
Monday I am bringing out my new Triplane for a maiden. Bring your camera.
Monday I am bringing out my new Triplane for a maiden. Bring your camera.
#214
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
Did the clipped wing cub fly heavy? It looked really nice.
I'll be there Monday and I will definately bring the camera. When are you going to be there.
Phil
I'll be there Monday and I will definately bring the camera. When are you going to be there.
Phil
#215
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RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
The clipped wing was quite heavy, I was surprized how much the paint added. Really the main problem I had with this Cub was ground handling. Not just typical Cub ground-handling but Demonic ground-loop handling. I realize that weight had nothing to do with ground handling problems but I figured ounce I tore into it I might as well see if I can make it into a nice aerobatic Cub. So we'll see. I built the thing like a Sherman Tank with the expectation of overpowering it.
I should be at the field Monday between 7am and 10 am.
I should be at the field Monday between 7am and 10 am.
#216
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
Well...
The wing tips are approaching their final shape. They still need some work, including some rounding, but I have removed a lot of the material. I am using a combination of some Permagrit sanding bars (Really efficient at balsa removal) and a sandpaper sanding bar. I worked on the tip at the front and rear then blended in the sides. Was not difficult once the work was under way. Holding the sanding bars is a good workout on the fingers though.
SunDevilPilot
The wing tips are approaching their final shape. They still need some work, including some rounding, but I have removed a lot of the material. I am using a combination of some Permagrit sanding bars (Really efficient at balsa removal) and a sandpaper sanding bar. I worked on the tip at the front and rear then blended in the sides. Was not difficult once the work was under way. Holding the sanding bars is a good workout on the fingers though.
SunDevilPilot
#218
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
The design of the Cub is definitely from the days gone by. It is probably twice as strong as a modern design but then again are some of the modern planes really built for a long life. I know of several Sig Cubs that are still flying and are about 20 years old. Dave's GP Cub is about 20 years old. I hope to get a lot of enjoyment out of mine so hopefully it holds together.
Phil
Phil
#219
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
SunDevilPilot,
you are absolutely correct.
20 years on a Sig Cub and it'll still be a youngster and ready for lots more use.
Mine was built about 1984-1985. After hundreds of flights on wheels and floats, about 12 years later, I sold it off to a guy who managed to butcher it pretty well although it still survived him. Some 5 or so years after that I bought it back and restord it to what it was. I finally lost it around 2006 due to radio interference.
While fling over mid field, at about 30 feet altitude, it went into a violent snap and spin to the left, with no control inputs. Instant toothpick fatory. No radio hardware problems. Used that exact radio - including servos, RX, battery and switch for many years afterwards without incident.
That's about the only thing that can kill these planes. They are extremely sturdy, reasonable weight for the size, have great presence in the air, look great and fly fabulously. You just can't go wrong with one. And your version looks great.
you are absolutely correct.
20 years on a Sig Cub and it'll still be a youngster and ready for lots more use.
Mine was built about 1984-1985. After hundreds of flights on wheels and floats, about 12 years later, I sold it off to a guy who managed to butcher it pretty well although it still survived him. Some 5 or so years after that I bought it back and restord it to what it was. I finally lost it around 2006 due to radio interference.
While fling over mid field, at about 30 feet altitude, it went into a violent snap and spin to the left, with no control inputs. Instant toothpick fatory. No radio hardware problems. Used that exact radio - including servos, RX, battery and switch for many years afterwards without incident.
That's about the only thing that can kill these planes. They are extremely sturdy, reasonable weight for the size, have great presence in the air, look great and fly fabulously. You just can't go wrong with one. And your version looks great.
#220
My Feedback: (50)
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
I can happily say that my old girl has about 19 years on her. She is the full wing sig cub with some modification done to it. Still had the same covering on her until a couple years ago when she was hit as i was back taxing down the runway.
#221
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
All the pre-planning for the flaps seemed to have worked out. I carefully parted the aileron and flap from the left wing and everything went as planned. I used an xacto knife to cut with the grain and a razor saw to cut across the grain. As instructed i took the handle attachment off a razor saw and used it to cut the ribs. While I was a bit skeptical this method worked without issue. I still need to true up the parts bringing them to their final dimensions then I will add the hard points for the hinges. Once that is done I will add the trailing edge of the wing and the leading edges of the aileron and flap.
Glad it worked as I was a little nervous to cut into my wing.
SunDevilPilot
Glad it worked as I was a little nervous to cut into my wing.
SunDevilPilot
#222
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
I have started to figure out how I am going to do the flap hinging. To do so I made up a template of the wing to see how the flap would function with the hinge moved around. I tried several different orientations of the hinge and this is what I came up with. This is most likely how I am going to configure the hinge. From my research I have found the hinge line of a real PA-18 is rear of the leading edge of the flap. However, I am not sure I want to go to the length it takes to cut such a hinge into the flap. With the hinge as it is there will be a small amount of air escaping from the bottom of the wing to the top which should help with the issue of ballooning with flap deployment. Thoughts?
Despite the hinging I have started to add the hard points into the surfaces.
SunDevilPilot
Despite the hinging I have started to add the hard points into the surfaces.
SunDevilPilot
#223
Thread Starter
RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
At the last Gunsmoke scale event at my flying field there was a Balsa USA 1/3 scale Super Cub that was awe inspiring. He has the scale flaps and ailerons on his model but as you can see they are quite complex. I don't think I have that level of detail in me.
SunDevilPilot
SunDevilPilot
#225
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RE: Sig 1/4 J3 Kit converted to PA-18 Super Cub (Build)
SDP, Im thinking less included angel on the flap hinge pin, this will increase the gap created when the flap is lowered.