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

[TooJung2Die]

This will be my first balsa WWII warbird. Okay, it's a military trainer but what could be more appropriate than a trainer for your first low wing warbird? The choice was even easier because it was a gift from a friend that doesn't like to build. Does this box really say 30 foot wingspan? 😉

Kit contents. It's an older kit and a bit different from the current Herr kit #114.

Let's get started with the easy stuff first.

Even though this kit is intended for rubber powered flight the plans have hinge lines for the rudder and elevator. That simplifies creating those control surfaces. 90% of this airplane is constructed from 3/32" balsa stick. The balsa feels very light. The goal is to build this as light as I know how.

Jon

 

[Grifflyer]

Looking forward to seeing this come together! Texans are such beautiful birds!

 

[OliverW]

Awesome! I can't wait to see the finished product!

 

[Bricks]

Are you going to use CA, to speed up the build?

Did you cover the plans with something by the picture it dosen`t look like it?

 

[Turbojoe]

You'll like the kit and the build. I've built a few Herr R/C kits but many years back I picked up the HRR108 Bonanza rubber powered kit and started R/C conversion. I didn't need to replace any of the wood. The kit is more than robust enough for R/C conversion. I used super light Hitec HB-45 servos. I made the cowl detachable using magnets. Still working on motor/battery choice and I'll do that after covering and I have a final weight to work with. For once I'll likely go with a lightweight and tame power package.

I don't usually build warbirds but I'm really looking forward to your build!

Joe

 

[speedbirdted]

Did you cover the plans with something by the picture it dosen`t look like it?

Looks like he put down wax paper, look at the upper left corner of the picture

 

[TooJung2Die]

Are you going to use CA, to speed up the build? Did you cover the plans with something?

Yes and yes. I use thin CA for almost everything on balsa builds. I love the stuff. It wasn't invented yet when I was a boy. A good CA glue joint is stronger than the surrounding balsa. The plans are covered with waxed paper as Ted pointed out.

You'll like the kit and the build. I've built a few Herr R/C kits but many years back I picked up the HRR108 Bonanza rubber powered kit and started R/C conversion.

That's very encouraging. The Herr website says kits that begin with 'HRR' are especially well suited for RC conversion. This is an older 'K' kit but I don't see any significant difference. Rudder and elevator are already there. I have to decide how to make the ailerons.

 

[speedbirdted]

I'm not even sure ailerons are needed. If it flies FF with the spec'd dihedral it'll probably do just fine with rudder and elevator only. I saw a Guillows Zero not long ago that had been built FF and had a similar amount of (non)dihedral and it seemed stable.

 

[TooJung2Die]

I'm not even sure ailerons are needed.

That's what I was thinking too. After reading as much as I can find about the AT-6 the experienced consensus says ailerons are a must for a low wing warbird unless you're satisfied with loops and circuits around the field. If you're looking to lose weight then skip the rudder and go with aileron/elevator. You don't need a rudder for flight and I'm a bank and yank pilot. But no rudder makes ROG take off nearly impossible. Decision time.

 

[GliderFlyer]

I'm watching this thread!

(hee-hee I stole that off of RC Groups)

 

[Willy Nillies]

Very cool!

 

[speedbirdted]

That's what I was thinking too. After reading as much as I can find about the AT-6 the experienced consensus says ailerons are a must for a low wing warbird unless you're satisfied with loops and circuits around the field. If you're looking to lose weight then skip the rudder and go with aileron/elevator. You don't need a rudder for flight and I'm a bank and yank pilot. But no rudder makes ROG take off nearly impossible. Decision time.

The main positive in my mind for building with just rudder and elevator is it allows you to use a UMX brick which will be lighter than having a dedicated receiver and ESC. Though, I'm pretty sure the type that use the geared coreless motors wouldn't be powerful enough to fly a 30" model. My rule of thumb for those is about 50 grams AUW or 24" ish wingspan, whichever you hit first. They do sell bricks that support 2s brushless motors (I think that's what the UMX Timber uses) but I can't speak for those.

I don't think normal servos would work for the ailerons. I think the wings are too thin. You could use linear servos or even these things. But I don't know exactly how you make a standard receiver correctly "talk" to a magnetic actuator - they only use two wires. It's something I've tried before without success.

 

[TooJung2Die]

This airplane is bigger than you think, Ted. It's bigger than the Willy Nillies line of airplanes. A pair of 3.7g servos will fit inside the wing with room to spare. If it weighs 200 grams or less when it's done I'll be happy. Most RC conversion warbirds of this size I'm reading about weigh much more.

 

[speedbirdted]

My sense of scale when it comes to small airplanes is very inaccurate. When I think rubber powered, for some reason my default size is peanut scale. I'm much better dealing with things in the 80+ inch range.

 

[OliverW]

My sense of scale when it comes to small airplanes is very inaccurate. When I think rubber powered, for some reason my default size is peanut scale. I'm much better dealing with things in the 80+ inch range.

same

 

[speedbirdted]

Though now that I think of it, this airplane will probably be able to accept full 4 function control. Just build it light

 

[TooJung2Die]

Though now that I think of it, this airplane will probably be able to accept full 4 function control. Just build it light

I agree, the fuselage is cavernous. There is plenty of room for electronics.

The left and right sides of the elevator are not joined in the plan so I made a 3/32" square strip from soft wood for the elevator leading edge.

Then I built the stabilizer. I put the elevator in the photo after the glue dried.

Tail feathers are done except for final sanding. I like the idea of 3 channel aileron/elevator/throttle. I never use rudder when I fly. The rudder has been glued solid to the fin.

Jon

 

[TooJung2Die]

Next step in the instructions is building the wing center section. Four of the ribs are doubled in front.

Having a flat bottom airfoil makes building the wing easy. You only have to pin down the center spar and trailing edge to assemble and glue the center section.

Finished wing center section.

Jon

 

[Timmy]

I always like watching people build balsa.

 

[TooJung2Die]

Here is the right wing pinned down and glued. No aileron is included in the plan, only the outline of the scale aileron. The scale ailerons looked small so I added 1.5" length to the scale aileron outline and built the frame. Pieces of waxed paper are inserted before gluing so the wing and aileron don't stick together.

Main right wing assembly placed next to the center section. The dihedral still has to be set so it has not been glued. The aileron frame is sanded to match the wing ribs. The aileron will be cut free when the time comes.

I always like watching people build balsa.

Me too! 🙂👍

Jon