Thunder Tiger Trainer – Repair, Refurbish and Conversion to Electric Power

I purchased on craigslist this Thunder Tiger Trainer N40TT which included a FM transmitter and a small box of miscellaneous parts. The plane is really old, dusty and rusty. It needs repair to the wing covering and a major repair to the horizontal stabilizer. I wanted the experience of refurbishing a balsa plane and the price was right so I decided to take on the challenge.

Here are photos from the craigslist ad.

Overall view.
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View of damaged horizontal stabilizer.
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Joker 53150

Mmmmmmm, balsa.
Mentor
Is that vertical stab fully sheeted, or is that covering? If it's sheeted you may be able to get by squeezing a little glue in there. The safe money says to tear into it and make sure it's secure, otherwise your flight may be a little short!
 
Is that vertical stab fully sheeted, or is that covering? If it's sheeted you may be able to get by squeezing a little glue in there. The safe money says to tear into it and make sure it's secure, otherwise your flight may be a little short!

It appears to be a solid piece of balsa. Right now I'm planning to glue and/or place a piece of heavy duty packing tape along the leading edge.
 
I removed the nitro engine, throttle servo, fuel tank, FM receiver and switch, landing gear and control rods. After removing the old hardware, I thoroughly cleaned the plane. I used Simple Green cleaner with a micro fiber cloth to remove the dirt, dust and grime. I blew out the interior of the fuselage with canned air. I put the remainder of the plane (airframe with three servos) on a scale and it weighed 2lbs 1 oz.

Fuselage interior before.
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Fuselage interior after.
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I don't like to keep stuff that I'll never use and I also don't like to throw stuff away that someone else could use. So I placed two ads on eBay. One for the engine parts and one for the transmitter parts. Bidding starts at $5 for each. I'll find out if one man's junk is another man's treasure...

Engine parts main photo on eBay.
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Transmitter parts main photo on eBay.
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Joker 53150

Mmmmmmm, balsa.
Mentor
Good luck with your sale. I did something similar with a plane I bought at a swap meet - I wanted the plane, but not the nitro engine that was in it, so I asked the internet if it was worth anything. The engine was un-used and had no muffler, and to me it was a paperweight. Turns out it was a desirable brand/size/vintage and sold for more than I paid for the entire plane! :)
 
I tested the throttle servo that I removed from the plane and it did not work, so I decided to do some internet research on Airtronics servos. I found out that the Airtronics servos on this plane have the older type connectors and that their wiring configuration is different than “standard” modern day servos. I switched the wires at the connectors by pushing on the tabs with a T-pin. Once I changed the servos to the “standard” wiring configuration they all worked fine. Now that the servos are working, I plan on using them instead of replacing with new ones. I’ll keep the throttle servo as a spare.
 

agentkbl

Illegal Squid Fighting?
I was reading this thread, just going "Why does Thunder Tiger sound familiar?"
Turns out my dad has a 1/8 scale nitro truggy, the Thunder Tiger ST-1, known to me as the TTST-1. lol.
 
The plane had wire main landing gear that was rusty. It also had 2-1/4” foam wheels which were bad and seemed too small. I’m a newbie and this plane will truly be a trainer so I want strong landing gear. I added some support to the fuselage interior (a piece of wood yard stick) where the main landing gear mounts. I installed a new Carl Goldberg glass fiber landing gear with new 3” Dubro Super Lite wheels. I hope this is not too much additional weight and is not overkill.

Old main landing gear

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New main landing gear

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The wire gear is actually quite resilient. There's a reason almost all of the trainers have wire gear. That wire can take a lot of pounding before it fails, and it absorbs energy with it its ability to flex. Make sure your new gear is not too tall. On a tricycle gear setup, you need to have the nose a skosh high, one for angle of attack, and also to keep your prop out of terra firma. The glass gear will probably be fine, but don't be surprised if you rip the bottom of the fuse out with a rough landing. The wire gear has more flex, where the fiberglass gear is quite rigid, and will transfer more energy to the fuselage.
 
The wire gear is actually quite resilient. There's a reason almost all of the trainers have wire gear. That wire can take a lot of pounding before it fails, and it absorbs energy with it its ability to flex. Make sure your new gear is not too tall. On a tricycle gear setup, you need to have the nose a skosh high, one for angle of attack, and also to keep your prop out of terra firma. The glass gear will probably be fine, but don't be surprised if you rip the bottom of the fuse out with a rough landing. The wire gear has more flex, where the fiberglass gear is quite rigid, and will transfer more energy to the fuselage.

The new gear has almost the same angles and dimensions as the wire gear that was removed. The plane may sit slightly higher with the larger diameter wheels. I also plan on also putting a 3" wheel in the nose gear so it should be a wash. Thanks for the advice. Lesson learned...bigger and stronger is not always better. :(
 

Joker 53150

Mmmmmmm, balsa.
Mentor
The stock landing gear wires are an old-school method which works well, as long as the wood doesn't get too beat up. The Kadet Senior I'm re-building uses that style, and I'll probably do a little surgery to clean it up a bit. Both styles work, and I like the look of your new gear better. You may want to use bigger washers on the bolts to spread the load out a bit.
 
I have never used film covering so my intention was to do as little covering on this project as possible. Unfortunately, this project will require more covering work than I expected. The wing has holes at the ribs on both sides, top and bottom. I don’t want to take the time and effort to remove all the covering and redo the entire wing. I decided to remove the covering around the wing ribs to the sheeting and just iron on large patches. I figured the sheeting would give me a nice smooth flat surface to iron on the patches. Hopefully I won’t have any problems with the new film sticking to the existing covering.

Top of wing before removing covering
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Bottom of wing before removing covering
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Wing with covering removed
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Joker 53150

Mmmmmmm, balsa.
Mentor
Are you going to try and blend in with the existing colors, or simply do a large single-color patch? The new covering will probably stick to the old stuff, but be extra careful on the leading edge of that new covering, as any spot not secure will open like a flap allowing wind in. Once that wind starts pushing into the wing cavity it's like more and more of it will come lose.

I think you said this was your first try with covering, so my suggestion is to simply go for something that works, with little focus on making it look good. Get it patched and airworthy, followed by another victory of seeing it in the air. If you're happy with how it flies you can always go back later on and make it pretty.
 
Are you going to try and blend in with the existing colors, or simply do a large single-color patch? The new covering will probably stick to the old stuff, but be extra careful on the leading edge of that new covering, as any spot not secure will open like a flap allowing wind in. Once that wind starts pushing into the wing cavity it's like more and more of it will come lose.

I think you said this was your first try with covering, so my suggestion is to simply go for something that works, with little focus on making it look good. Get it patched and airworthy, followed by another victory of seeing it in the air. If you're happy with how it flies you can always go back later on and make it pretty.

Yep, I agree with you. My goal is to get this plane airworthy by spending as little time and money as possible...and gaining some building experience in the process. I don't care about exactly matching the existing graphics. I plan on just doing two red patches on the top and two white patches on the bottom. I think that will look good enough.
 
Good luck with your sale. I did something similar with a plane I bought at a swap meet - I wanted the plane, but not the nitro engine that was in it, so I asked the internet if it was worth anything. The engine was un-used and had no muffler, and to me it was a paperweight. Turns out it was a desirable brand/size/vintage and sold for more than I paid for the entire plane! :)

eBay auctions have ended. I paid the craigslist seller $30 for the plane and I made $20 for selling the parts on eBay. I didn't cover the cost of the plane but I do feel better about not throwing parts away that others will use.
 
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