Robbe Arcus Motorglider

Robbe Arcus Motorglider

Introduction

This article is about my first "build" of a rc airplane, and it is also my first article on Flite Test. In this article you will read about the build of the Arcus and maiden flight. I hope you will enjoy the article. And please leave a comment!

Background

I started with the rc hobby in the summer of 2015 when I got a Hobbyzone Duet because I graduated to High School. After charging the bateries, "reading" the manual, etc. I went to a local football pitch and had my first flight. Unlike so many maidens, it went perfect! I didn't crash and I had no difficculty flying towards me. 
I flew there a couple of times and got pretty good at flying it. Then I heard that a rc model club moved to the village I live in. So I went to the flying field and asked if I could fly there. They said: "Ok, show us what your're at." I took off and flew without any problems, I only almost had a mid-air with another aircraft... They were quite impressed that I could fly a rc plane without any training or help. 
And so they asked me if I wanted to come over again some day and so I did. One time a club member said that he had an "old" plane laying around that I could have, the Arcus.
And +/- 2 months later it's flying almost perfectly.

Specs

Wingspan: 1800 mm or 71 Inches
Length: 1200 mm or 42 Inches
Powerplant: D-Power Brushless Motor AL28-09, 1380KV
Prop: 10 x 5 full carbon, folding prop
Esc: Hobbywing Skywalker BL, 20A 
Battery: Zippy Compact 1000mah 2s, can go up to 3s with 9 x 5 prop
Servos: Hitec HS-53, 8 gram servos 

The Build

I started this build with installing the servos for the rudder and elevator. These are mounted in the canopy on small wooden planks to give them extra secureness. (see picture below)

 Next, I installed the aileron servos on the wings. Here the problems started. A servo extension was already installed but it had very small ends on it so soldering was impossible. I had to, carefully, pul out some more of the wire to be able to have enough of the material to solder. Because of this I riped some of the foam making a small channel. This, although it was an accident, helped me with routing the wire. 
To fasten down the servo I used heavy duty doublesided tape. It was the only glue/tape I had laying around so I decided to try it. It turned out to work really well. Finally, I closed off the channel with a piece of tape. (see pictures below)

 Finally I had to install the motor and esc. This was the hardest and most frustrating part of the build. It was because I didn't have anything to fasten the motor to. The original kit cane with a special, plastic motor mount tray but I didn't have that and I couldn't find it online. So I had to figure out another way to install it. It went to a local hardware store and found some PVC 32mm tube with a closed end.
I drilled 4 holes in it and screwed the motor on it. This as a whole I glued in the nose of the airplane using PU-glue (poleurethane glue), the glue expands into some sort op tacky foam. This can be seen in the picure below. Also this is surprisingly strong.
The esc I just friction-fitted in using a piece of foam. (see pictures below)

In the picture above you might notice the small module in between the two servos. That's one of Graupner's telemetry modules. This one measures my battery's overall voltage and the voltage per cell. 

The Maiden

The maiden went surprisingly well. I had no big issues whatsoever.
When I arrived at the flying field I immediately started to assemble the plane, making my connections and checking the CG. Everything was fine so she was ready for her first test-glide. A clubmember threw the plane for me and it glided pretty nicely, probably around 20 meters (65 ft) on 2 meters (6.5 ft) height. Everything was ok so she was ready for her first flight.
I slowly gave full throttle and the clubmember threw her. The plane started a 45 degree climb. I had to give a little bit of down input to compensate for the high lift wing, but that's completely normal for a motorglider.
She flew absolutely amazing! Real gentle on the turns and stalls, very manoeuverable and with a pretty good penetration. This would be a great second or third airplane for anyone who has never flown a 4 channel airplane before, but also the more experienced pilots among us can have a great amount of fun with this plane. On a summer-afternoon when there's lots of lift this plane will soar forever!

 She really has a presence in the air, hasn't she?

How can something that big look so small in the air.

Conclusion

I absolutely love this plane! It is fun and easy to build, looks great and most importantly: it flies great. I would definately reccommend this plane to any pilot with some flying experience. Unfortunately this plane is out of production and is very hard to get, as well as replacement parts. But if you get the oppurtunity to buy one of these: DO IT, you'll have years of fun with this if yoy don't destroy it ;). 

Please give me feedback on my article so I can, if necessary, make changes to this article and use your feedback for the articles to come. A small video on the Arcus will be on YouTube in the near future!