"AT-6 Texan" Herr Kit #114 Rubber Power to RC Conversion

[TooJung2Die]

Whoops. Reminds me of when I tried to glue servos in using thin CA. What's stopping you from just screwing them in?

I think everybody learns the CA and servos don't mix lesson. 😆 I cut the ears off the servos to make them fit better. Servos are working again. The only good thing about having to do something twice is you should be able to do it faster and make it better. No point posting another wing photo; repairs are complete and it looks no different. 😎

 

[BATTLEAXE]

@TooJung2Die i like how this is going together. I am seeing some tricks you have going on in this that I will copy cheat and steal. Great work

 

[telnar1236]

The plane looks great. That's too bad with the servos. Sealing the seams on the servos with a very thin layer of painters tape can help prevent these issues, and then you can mount them using a very judicious application of CA to save weight. I've never had any issues using that method.

 

[danskis]

Yep...I'll never use CA for servos again. It was medium CA but still....
Others in the club wrap their servos with painters tape.

 

[TooJung2Die]

Painters tape? That would make peeling it off in the future less of a hassle. 👍 I disassembled the stuck servos and easily removed the tiny blobs of glue that were binding the gears. While the servos were apart I used a toothpick to coat the gears with the excess grease you'll find clumped around the gear train. I used 'scotch' tape to seal the servos before gluing them back into the new servo trays.

All the major assemblies are sanded and ready to cover. Gussets were strategically added to the wing trailing edge. Balsa to mount the aileron control horns is added. Everything is taped together and the electronics are positioned inside to get a ballpark idea of where they need to go to achieve the correct CG without adding ballast.

The airplane is balanced on a piece of 1/4" square stock under the wing main spar. A 450mAh 2S battery slightly forward of the wing main spar got the balance just right. At this point, before covering and painting, it weighs 4.8 ounces.

Jon

 

[Willy Nillies]

Very nice! This should be a real floater at that weight!

 

[TooJung2Die]

The covering is finally going on. I'm using 1.5 mil standard document laminating film from laminator.com. Easy pieces first so I get used to this film and the best iron temperatures. That's the huge 500 foot roll of film I bought. I'll never use it up.

Doculam is perfect for delicate balsa frames. It shrinks gently. This is my covering tool kit. The bean bags are good for holding wings without breaking balsa.

Here's a trick I learned for using document laminating film. Leave plenty of excess film overhang and don't trim it until after the film has been shrunk tight. If there are wrinkles that don't shrink out you can apply the iron to the tacked down edge and pull out the wrinkle.

This first wing panel turned out smooth and wrinkle free. The excess has not been trimmed off yet. Crank up the heat so the film softens and it can be stretched over compound curves like the wingtip in the photo.

Jon

 

[rockyboy]

Looking great! I need to make sure on my next one to leave that wingtip overhang longer so I can pull it like you did - that looks really smooth out there...

 

[TooJung2Die]

Wing is completely covered.

The covering film wrapped nicely over the wingtips. The top including the tips is covered with a single piece of film.

The wheel fairing is fitted and glued in place.

Bottom of the wheel fairing. The bottom balsa piece from the kit was not used. I couldn't see any useful purpose for having open holes for wheels that don't retract so I made the bottom closed up.

Jon

 

[TooJung2Die]

First strip of fuselage covering on the bottom tail. This fuselage is going to be a challenge. Every surface is a compound curve. I needed to use the heat gun and glove technique to get this little strip stretched and smoothed out.

Jon

 

[speedbirdted]

Looking great. What will be your paint scheme? I personally like the RNZAF colors. It's pretty simple, and you don't see it done very often.

 

[TooJung2Die]

New Zealand has a colorful livery. I'm inclined to use a simpler, more common scheme. Fewer colors and less masking equals a better chance for success.

 

[Jesse Dupreez]

The covering is finally going on. I'm using 1.5 mil standard document laminating film from laminator.com. Easy pieces first so I get used to this film and the best iron temperatures. That's the huge 500 foot roll of film I bought. I'll never use it up.

View attachment 191269

Doculam is perfect for delicate balsa frames. It shrinks gently. This is my covering tool kit. The bean bags are good for holding wings without breaking balsa.

View attachment 191270

Here's a trick I learned for using document laminating film. Leave plenty of excess film overhang and don't trim it until after the film has been shrunk tight. If there are wrinkles that don't shrink out you can apply the iron to the tacked down edge and pull out the wrinkle.

View attachment 191271

This first wing panel turned out smooth and wrinkle free. The excess has not been trimmed off yet. Crank up the heat so the film softens and it can be stretched over compound curves like the wingtip in the photo.

Jon

is that just like laminating pockets?

 

[TooJung2Die]

is that just like laminating pockets?

That's what I've heard. From what I've read the pockets are the same material but thicker film.

 

[TooJung2Die]

This fuselage was, by far, the most difficult covering job I've done to date. It took a week of working on it over several sessions. It took 26 pieces to cover and almost every one was a compound curve.

The heat gun was needed on every section. The hardest sections had a combination of convex and concave surfaces like the little section right behind the cockpit and the battery hatch. There were a lot of do-overs but it was a valuable learning experience.

Jon

 

[Bricks]

All that work and cannot even see the covering.

 

[TooJung2Die]

All that work and cannot even see the covering.

Or my mistakes! 🙂

 

[rockyboy]

Looks great from here!

 

[TooJung2Die]

The elevator is hinged using monofilament. Mono is great when the wood is too thin to slot. When the push rod length is just right a couple of drops of CA on the heat shrink tubing locks it in place. The control horns are gift card plastic.

The ailerons are hinged using Tyvek mailing envelope. The push rods are made from short Z-bend wires connected with heat shrink tubing.

The wing is supposed to be glued to the fuselage. Since this is going to be a belly-flop lander I added bamboo skewers to hold the wing on with rubber bands.

How much weight does document laminating film add?

Before covering it weighed 4.79 ounces. Covering, mounting the electronics and finishing the control surfaces added 0.64 ounces. I'd estimate the film added 0.5 ounces to the airplane. The CG moved to the rear as expected and now the battery has to be right behind the firewall. It'll be interesting to see how much weight painting it adds.



Jon

 

[TooJung2Die]

I've always wondered how much weight the covering film and paint adds to the weight of an airplane. I never stopped to weigh the model between steps until now. Paint does not add as much weight as I thought.

That's 5 airbrushed coats of very thin acrylic paint. I stopped adding coats while the paint is translucent and the balsa frame can be seen though the covering. One coat of clear aerosol lacquer on top of that. The black acrylic trim was masked using Scotch Removable 811 tape and brushed on. The paint job only added 0.4 ounces. At this point with the battery on board it weighs 5.82 ounces (165 gram). Ready to fly it'll be well under the 7 ounce, 200 gram goal. Not bad for an airplane with a 30 inch wingspan.

Next steps are attaching the canopy and applying the decals.

Jon