Rc Scratch Build 20CC Just Aircraft Highlander

by Rafael R. | November 10, 2016 | (12 Ratings) Posted in Projects

 

Hey Flite Testers, I'm working on a project and thought I would share my progress. A little over a year ago I was looking through YouTube and stumbled on a video of a Just Aircraft Highlander. I directly wanted to build that plane. So I searched the Internet for Plans and found a 54 inch version of this plane from Scott Swanson . I liked his plans but since I already had a lot of small planes I felt the need for something bigger. I decided to upscale his plans by 164,7% equivalent to a scale of 1/4,25. This would keep the length of the plane under 1,5m and it would still fit in the back of my car. It was my first giant scale airplane. I learned a lot by trial and error and I’m by no means an expert on this topic but I still hope you are interested in my project. I’m very happy with the way it’s come so far.  It was a fun process…  

The specs are:

  • Wing Span: 225,9cm.
  • Scale: 1/4,25
  • Flying Weight: 4,95kg
  • Motor: DLE 20CC Gas Engine
  • Prop: Menz 17x8 
  • Receiver Battery:  Zippy Flightmax 1100mah 6.6v LiFePo4
  • Ignition Battery:  Zippy Flightmax 1100mah 6.6v LiFePo4
  • Servos: 7x HobbyKing Ball Bearing Analog Servo 39g/4,5kg/0,13s
  • Receiver: Spektrum Ar9020 with two Satellites

Wing construction:

Scotts plans call for balsa build up wing. In the past I had a bad experience cutting a bunch of ribs out of balsa and trying to align them all. So I decided to cut my wing out of styrofoam using a hot wire foam cutter

My hot wire foam cutter.

The templates for cutting the wings.

After cutting the wing out of a styrofoam block I epoxied 4mm plywood ribs to the root and the middle of the wing. They secure and keep the two wing tubes aligned.

For extra stability I reinforced the top and bottom of the wing with 20mm fiberglas band soaked in 24 hour epoxy resin.

In the next step the still wet band is covered with a strip of doubled up tape and is than...

...sandwiched between wing shells. 

While drying the wing is pressed betwenn two wodden board to keep it flat and straight.

Here you can see the two wing tubes I was mentioning earlier aswell as the now dryed fiberglas band. I cut a small hole in the wing to make space for the wing connector and for all the wiring.

Next the aileron and flap servo wires get installed.

With the wiring now in place the wing can be covered with 1mm balsa.

The finished wing root before covering.

The wing tip was constructed using 3mm balsa.

The wing before covering. In order to save weight I removed every second wing section. The wing is still strong enough and I saved 50g per wing. This might not seem like a lot for an airplane this size, but it adds up overtime.

Picture of the wing servo mount. I made in total four of them, two for the ailerons and two for the flaps.

The finished wing from the bottom.

The finished wing from the top.

Fuselage Construction:

The fuselage was build mostly according to Scotts enlarged plans. Nevertheless I used pine strips instead of balsa strips in many places to account for the greater weight.

The four main fuselage formers.

The formers are then connected with 5x10mm pine stock.

Then the rudder is added... 

 and with the firewall and the cockpit structure in place it starts to look like an airplane.

Working with pine instead of balsa wasn't always easy. To fill up small gaps in the joints I used pape soake in thin CA. Later i drilled a small hole through all structual joints and glued in a toothpick for added strength.

The last important step is to glue on the fuselage side covering made from 1mm aircraft plywood.

Starting the engine for the first time was really tough. I had absolutly no experience with gas engines and nobody around me who could help me. But once the carburator was wet it started fine with just a few flips of the propeller. I used a digital tachometer to check the RPM of the engine which made adjusting the carburator a peace of cake. Once I was satisfied with the engine performance ... 

...I installed it into the airplane. By now only three things were left. I had to laminate a custom cowling, I had to construct and build a landing gear and I had to cover the whole fuselarge.

Unfortunately I have no pictures of the cowling lamination. But I want to tell you one thing. A shiny cowling need a lot of sanding and filling and by a lot i mean around 10 hours!


Landing gear Construction:

The landing gear was build using 4mm spring stell and 5mm rass tubing. 

The two landing gear legs after painting.

All the pieces of the landing gear hung up for painting.

 The finished landing gear.

After covering the fuselage looked amazing. After over 12 months of work she was almost ready for flying. I still had to cover the right wing but that didn't stop me from assembling the whole plane to finally get a feel for the size. Because so far I only had  a few plans and a big vision in my mind. The first time I assembled the complete plane. It's huge! It just barely fits into my basement. 

The finished plane:

Maiden flight:

It was the first time for me to fly a large scale gas plane so I was excited to get it in the air. Last check before takeoff...

...and with half throttle...

...the Highlander took off and was in the air in no time!

Flying this large scale plane and hearing the sound of the gas engine were both a really fun experience!

COMMENTS

MikeRobey on November 12, 2016
Nice build and nice article. It was both interesting and enlightening to see how a traditional foam core wing goes together. Result looks stunning. Well done!
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ttprigg on November 12, 2016
Great work Rafael. Your build is well documented with with lots of good solutions (removing foam sections and toothpick reinforcements). I just don't know that I would be willing maiden it... I was hoping for a video but your still photos captured the perfect moments!
Thanks for putting the article together.
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Rafael R. on November 13, 2016
Thank you for the kind words. I want to add a flying video soon. We currently have really bad weather and I hope that we get a nice day to fly again soon.
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earthsciteach on November 12, 2016
Congrats on building such a spectacular model! Thanks for sharing!
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Rafael R. on November 13, 2016
Thank you.
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FlyingMonkey on November 12, 2016
Not sure if you're a Facebook user Rafael, but you're getting some very positive comments from the guys here... https://www.facebook.com/groups/1510169962560076/
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Rafael R. on November 13, 2016
Thank you for the tip with the facebook group! Lots of great projects there.

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Krümelmonster on November 13, 2016
Very nice documentation of your build. Congratulations for a very clean build and well looking airplane. But why should somebody drink Paderborner export voluntarily?;)
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Rafael R. on November 13, 2016
Thank you. The beer belongs to my dad and we all know that nobody is perfect. ;)

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frankenplane on November 17, 2016
What do you mean the wings don't fold back.... Actually wow what a great plane, I am a real fan of the justaircraft guys and could tell at a glance you had done one. Great work.
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Kaiser Soze on November 17, 2016
Great job !! Nice work and documentation. I would like to do one of these also, as soon as I have the shop cleaned up that is. Looks like a neat and clean design. Where did you get the plans for the foam cutter? I've never seen one like that before.
Eric
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Rafael R. on November 21, 2016
There are no plans for the foam cutter. I got inspired by old wood saws. However the construction is really simple. For the main H frame you can use steel or wooden booms. Then you bolt them together with machine screws so they can still turn. On one side you mount the wire and on the other side you mount a Turnbuckle and a rope in order to tighten the wire. To power the foam cutter i used a brushed ESC as described in the Flitetest Hot Wire Foam Cutting episode.
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Paulshort on November 17, 2016
Great article. Well written and some very inventive solutions
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JamesWhomsley on December 6, 2016
Great work on the plane and the article. I very much enjoyed reading this.
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stefanostergren on April 10, 2017
Hey Rafael!
My name is stefan and I work as the Community Engagement Manager at Flite Test.
Do you happen to have VIDEO of your maiden flight or ANY FLIGHT for that matter? If so Please send it to my Email: stefan@flitetest.com
I would like to showcase this build and I think having video in the episode would be a GREAT added bonus!
Just let me know! THANKS!
keep up the great work!
Blessings,
Stefan
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stefanostergren on April 19, 2017
Hey Rafael!
Stefan again, Is there anyway you could still possibly send me some of your FLYING footage from your highlander? If you have it? That would GREATLY help the episode. If you have anything that we could possible use, please shoot me an email at my email: Stefan@flitetest.com

Thanks my friend!
Blessings,
Stefan
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Hawki on April 24, 2017
Hi there Rafael ...
I just had to comment on your beautiful project. The workmanship is an inspiration to many of us to just do it right. You have a lot to be proud of and I will hopefully see more outstanding work like this from you in the future.
My very best,
dave
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