Sig Kadet Senior, Rescue & Rebuild

[Joker 53150]

Yup, I'm starting yet another project. The work on the big L-19 has slowed down now that flying season is approaching and there is no way it'll be ready to fly this year. Plus, the other planes needing work are piling up and I want more large flyable planks for the season. I'll come back to it from time to time, but for now I want to get some other projects finished. The 1/4 scale Cub is approaching the finish line, the detail work on the 1/4 scale Pietenpol is also almost finished, and I've now got the electronics to update another 1/4 scale Cub (Clipped Wing version).

This Sig Kadet Senior I got from an estate sale a few weeks ago. The picture posted in the advertisement looked promising, but when I got there and was able to see it in person I found it was pretty rough. It's got some years on it and there has been nose and tail damage. The vertical stabilizer was a bit wobbly, the nitro engine was seized, and covering was janky. But for the price it was worth trying to save it. Plus, Sig still makes the kit so all necessary parts would be available. Some items I knew were going to be needed, so an order was placed with Sig for the following:

• New windshield
• New side windows (simple flat plastic sheet)
• New landing gear (just in case)
• New tail feathers
• New hardware kit

Sig's parts are fairly inexpensive and good quality. Anything I didn't need would be used elsewhere on a different project. While I was at it, I also ordered the landing gear for the Sig Kadet Seniorita kit I have, as it was missing the pieces when I bought it. The electronics going into it are the same as I used in the Sig Astro-Hog, and it'll use the same 5 cell 5000mAh packs.

So here is the Senior as I bought it. From this angle plus a generous helping of distance it looks pretty good! Oh, but wait...




Lets get a closer look at the fuselage.




The engine is seized, no idea if it can be salvaged yet, but I don't fly nitro so it doesn't matter much.




The windshield is fairly "aged"...




The pilot looks like he's taking time off from the Italian restaurant he manages.




The tail looks OK. Covering is a bit beat up and there are plenty of patches.




With the covering removed (mostly) I'm finding all kinds of repair work done at the tail. There are also a few broken glue joints which need to be addressed. This is about what I was expecting, and why I ordered the replacement tail feathers from Sig. These could be patched fairly easily, but gluing together some fresh balsa will be MUCH easier than screwing around with exhaust-soaked old stuff. There is also quite a bit of epoxy holding the horizontal stab in place. Replacing the pieces with new and using less glue should also decrease weight at the tail.




The horizontal stab has the most damage. Again, it'd be fairly easy to repair the breaks, but a new piece will be easy to build and will be much stronger.






There was some damage at the nose which was repaired some years ago. I'm not sure what the builder did, but the covering on the patch doesn't want to come off. As with the Astro-Hog rebuild I did last year, the plan is to cut off the sides of the nose (which surrounded the engine) so I can prep it for an electric conversion. Once that is done I'll re-build it around the new power plant.

 

[Joker 53150]

With the covering removed I found a lot of the balsa was "oily" from the nitro fuel and exhaust. I've seen this before when I re-built old nitro planes, and it's a bit of a pain when it comes to covering the model since the covering doesn't stick well to that oily film. I asked online about ways to deal with it, and a popular answer was "K2R" cleaner, which you spray on and let it dry. Well, I couldn't find it at my local stores so I went with another popular method that uses a spray-on de-greaser followed by baby powder. It's supposed to draw out the oils from the old gas if it's left on the wood for a day or so. To test it I sprayed the firewall and one side of the fuselage, and then covered it with the baby powder. Even if it doesn't work well, my shop smells better! Tonight I'll remove the powder and apply another coat of it.

 

[Turbojoe]

I used to use denatured alcohol to clean my glow powered planes and trucks way back when I still played with that nasty fuel. I never tried it on thoroughly oil soaked wood but on the repairs I did it worked well to clean and dry the wood. Haven't seen K2R in a long time but I do remember it smelled pretty wicked.

Joe

 

[Joker 53150]

I've got plenty of alcohol at home, some of it even denatured. The bottom hatch needs a lot of clean-up and will probably just be replaced, but it would be a great test-piece to see what the denatured alcohol can do. Thanks for the suggestion!

On a different note, this plane was interesting to disassemble. The radio gear and gas tank were surrounded by a few dozen sheets of paper towel and foam padding. I kept reaching in and pulling out more and more! If it ever caught fire it would have made a great bonfire!

 

[Joker 53150]

After one day the baby powder seems to be working fairly well. Most of it is still dry and powdery, but the stuff closest to the wood is certainly soaking up some oily residue and is now thicker and clumpy. I reapplied over a bigger area and will check it again tomorrow.

 

[rockyboy]

I have a restoration project with the same fuel-soaked balsa condition so I'm really hoping your solution works for both of us

 

[roversgonemad]

I have used the K2r, but haven't bought any in a couple years. I was able to find it at the local Ace hardware. I'll also be curious to see how the baby powder and alcohol work. I don't have anything too fuel soaked right now, but you never know when you'll find that old old plane you just can't say no to.....

 

[Joker 53150]

I'll check my Ace and see what they've got. They were closed by the time I went looking for it the other day.

Regarding the baby powder (which still looks promising), I'm not entirely sure how I'm going to clean it all off since it's such a fine powder. Most of it will easily brush off, but there will still be some in the nooks & crannies. A shot from the air compressor will probably take care of most of it, but I'm wondering if a quick rinse with water would also help. I've had a plane submerged in very wet mud for a short period of time with no ill effects to the balsa.

Thoughts?

 

[Joker 53150]

The powder appears to be working pretty darn well. This afternoon I started by wiping off as much of the fuselage as I could reach, as the powder was moistened by the oils and was sticking a bit to the wood. After that, I took it outside and hooked an air nozzle up to my compressor and removed as much as I could with air. The powder has drawn out enough oil to really stick well to the firewall, and in the picture you can see a gray appearance to the black firewall, thanks to the residue that didn't come off with air. It'll need to be brushed or maybe removed with a brush and water, we'll see what happens. The fuse was taken back to the shop and coated with more baby powder, and I'll probably let it sit until Thursday before removing it this time.

I'm going to borrow the plans from the Kadet Senior kit I gave my dad a few months ago so I can use them as a guide to re-build the upper cabin side window areas. These are just too far gone considering they carry the weight & force from the wing. I can easily re-build them and splice them into the rest of the fuselage - cheap insurance against a catastrophic flight failure...

From the last picture I posted a few days ago you will also notice I cut off the side "cheeks" that go on either side of the motor. They were beat-up, fuel-soaked, and would simply have been difficult to work with, so I'll take it all right back to the firewall as I move forward with this frame-off restoration.

 

[RCMAN]

Love it, you will never see a foam board airframe last that long. Nothing like balsa and wood!

 

[Turbojoe]

It's working like pleasant smelling kitty litter. I never tried it on a plane but diatomaceous earth like is used for pool filters is amazing at sucking oil spills out of concrete. I wonder how it would work on wood. Looks like you're getting good results with the baby powder.

Joe

 

[Joker 53150]

So far so good! I'll fire up the compressor tomorrow and give it a thorough blast of air, followed by a barely damp rag. Tonight I'll just give it a quick brush followed by fresh powder.

 

[Joker 53150]

Love it, you will never see a foam board airframe last that long. Nothing like balsa and wood!

No argument from me on that. Foam is certainly nice and cheap, and super fast to build with, but it's just not my cup-o-tea.

 

[Joker 53150]

By tonight the powder treatment will be done. Checking it last night, the only thing it's not really absorbing is the weird filler the builder used around the windscreen. It scrapes off, but is somewhat "waxy" in consistency so I'm trying to keep from spreading it around. After I return from a work trip next week I'll evaluate how much of the old structure will be cut away. The tail where the horizontal stab mounts will be a quick re-build, and I'm probably going to replace most of the upper cabin area below the wings. The original plan was to also replace the firewall, but the powder appears to have done well enough that it won't be necessary. So that'll be a game-time decision as I start pruning the damage.

 

[Joker 53150]

It could be argued that I'd have been better off just building the Kadet from scratch again, but there is a certain satisfaction I get from rescuing a plane that otherwise may end up in a landfill. This fuselage was borderline, and I'm pushing forward with the work now that I'm back from a few days work in Dallas (we got to have dinner ON the field at Texas Stadium, which was pretty cool).

I've stripped the fuse down, removed any broken bits, any spongy wood, and any pieces that weren't securely glued. At the front, this meant all of the upper cabin structure and at the back it's quite a few sticks. Once I get the plans from my dad I'll start putting it all back together with pieces I've got on-hand, plus the new tail surface kit from Sig. The dismantling of the tail might look severe, but it'll be pretty quick and easy to put back together.

 

[Turbojoe]

Looks like you're hacking yours up pretty good in the rebuild. What are your thoughts related to the cabin area? Does it need a little CF? I've seen a few posts on other forums where guys have reinforced that area. None really said why. I guess they just thought it needed it.

My kit is still in the factory shrink wrap until I make some room. I sold off a few kits but that's a much bigger pain in the ass than I ever imagined!! Sure wish I could find a deserving local entity to give about 20 airplanes to so I could free up a little space. I really need the room but it would piss me off to no end to give a bunch of planes away only to see them on Craigslist or ebay within a week! Who can you trust anymore?

Joe

 

[Joker 53150]

A little CF wouldn't be a bad idea, and I may run some vertically down from the wing saddle into the side-sheet for the fuselage. If I were to fly it gently it wouldn't be a big deal, but I want it to last and I don't want to worry about it.

Another option would simply be to use harder balsa and mortise & tenon the pieces to lock it all together. I'm getting away from the rubber bands that held the wing on, in favor of a bolt-on wing. Some additional structure will be required to make that happen, but again it shouldn't be too major. In the end, I want the forces on the wing saddle to get transferred down into the fuselage better than they were.

To unload some planes, maybe approach a Boy Scout troop (or something similar) and offer to give flying lessons. Anybody who completes the "TurboJoe School of RC Flight" and also does a bit of community service gets a free airplane!

 

[Joker 53150]

Tooling around on Ebay I found something interesting. A guy is selling re-printed copies of the Kadet Senior plans, fairly cheap. I may just buy them so I don't need to get the plans from my dad from his kit. Then I could cut this copy up and keep his original mint.

But what is even more interesting is that he also prints the Kadet Senior plans at 150% and 200% size. The 150% pushes the wingspan to 117" and the 200% is 156"! As much as I enjoy giant scale planes, 156" span is a little big, even for me. But I may order the 150% plans, along with plans for a 100" span Ugly Stick. Maybe...!

 

[Turbojoe]

You know Sig sells the plans for only $10.99. LINK I don't know what shipping would be though. I bought a bunch of Kobra landing gear, canopies and plan set a few years back and I remember shipping being very reasonable. Of course if you still wanted larger scale you'd have to have that done local.

Joe

 

[Joker 53150]

I'd certainly buy direct from Sig if I only wanted the Senior plans, but the same seller has a lot of plan sets and I'm trying to bundle for cheaper shipping.