Sbach 342 Empennage – Build Update 2

I had hoped to get most of the empennage, the tail feathers, done by the first weekend after starting work on the Sbach 342. Well…

Making Some Progress on the Sbach 342

Horizontal stabilizer fitted and epoxied in place.

Horizontal stabilizer fitted and epoxied in place.

I tried to get the horizontal lined up just right. I spent time measuring and making sure that each half out of the fuse was the same distance. To me this is “centered”. I then measured from the tips to the center of the motor box. There was about a half inch difference. After wiggling things around to correct this I thought I was good. I mixed up some 30 minute epoxy and added some microballoons. Standing behind the plane everything looked to be pretty close!

Testing Elevator Fit

Testing Elevator Fit

I took some T-pins and put on one half of the elevator just to see how it would look. I’m really excited!

Empennage Partially Complete

Empennage Partially Complete

The following night I hinged both elevators. This process was again pretty painless. I did see that my  horizontal is not even on the left and right. It looks like I may be an 1/8 of an inch off! I don’t understand why the tip to center of the motor box would be off. I’ve done this on other planes and haven’t had any issue. Hopefully this won’t negatively affect the flying.

I also cut out one side for an elevator servo. Installation of the servo was kind of weird. I didn’t take a picture of how the servo mounts in but I’ll try to do it when working on the other side. The hole in the monokote isn’t big enough for a standard sized servo. After cutting the section out I was starting to get upset because I had just cut a sizable chunk out and didn’t know what to do. Looking across the fusealge at the other side I could see dotted lines on some ply in the same place where the other elevator servo would go. I guess they made it so you could run a set of smaller servos. Anyhow, I cut the ply out so that my standard servo would fit in fine. The frame to hold the servo wasn’t glued in very well and I had to to apply some thick CA to get it reseated and fill in some gaps.

After getting the servo all set in I went back to the manual to double check that I hadn’t read anything wrong. It turns out that I didn’t. There isn’t any info that mentions cutting out the servo mount for a standard sized servo. They do clearly show a standard size servo in its place. My only concern was that looking at the instructions it showed the elevator halves connected by a wire. This would allow a single servo to drive the whole control surface. My Aviator and Red Bull 540 are setup this way. I didn’t have the U shaped wire to connect the two halves so I just assumed that this Sbach 342 was designed for dual elevator servos. My concern ended up being that now I have two large standard sized metal gear servos at the back of the plane. This would make the relatively light plane tail heavy. I’m going electric with it so I’m hoping the large 5000mAh 6s battery will be heavy enough to balance it out. I’m planning to run a separate flight pack battery so that should add a little more weight to the nose which should help some more.

Up Next…

In the next post I’ll be detailing the rudder and tail wheel installation. I’m also going to be doing some reenforcing of the landing gear area. I want the Sbach 342 to last more than one landing! The one build and review that I read on this plane said that this area is especially weak on this model. I’ll be using some 1/8″ and 1/16″ ply to help redistribute some of the forces that are applied there. I’m also thinking of adding a piece of ply along the bottom of the fuse near the landing gear instead of just the stringers which are there now.

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About Mike

I'm a software engineer. Look into the about page for more information about me.

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