1.2m depron Acrobat build

by apnewton | April 20, 2015 | (13) Posted in Projects

I was keen to try some aerobatics with powered planes but none of my existing motor gliders was up to the task. Too "glidey" and not enough rudder. So this is what I came up with. It uses a few different build techniques including a very narrow tail forming part of the fuselage and a full flying elevator.

 

It has a 1.2m x 180mm 12% chord Armin wing and a 700mm fuselage both made from 6mm depron covered with 75 micron document laminating film. That is the thicker of the commonly used laminates and it added lots of strength. 

For the fuselage I usually cover the depron or foamboard with tape first then make it into a tube. This time I started with flat panels of uncovered depron.

The sides were glued on top of the bottom panel, which defines the width of the front area.

The tail halves were glued together giving the taper curve, then top and bottom panels added. 

The fuselage was then covered with 75 micron laminate. 

This added a great amount of strength, especially to the narrow tail area.  

The 2826/10 1400kV motor is mounted to 5mm plywood with ventilation holes drilled out. Initially I built in some down thrust but I am still testing to find the right amount. Plastic washers can be added or removed to vary the angle. 

The most radical feature of this design is the flying elevator. The whole horizontal stabiliser pivots on a 3mm carbon fibre rod which also acts as the spar. The rod passes through a brass tube glued into the tail. The inner diameter of the brass tube must be just bigger than the CF rod to give free movement but minimal wiggle. To hold the brass tube firmly there are 25mm discs of foam sandwiched between ID card plastic on either side.

Watch the build video below for full details

This plane has turned out to be a great performer with unlimited vertical and great aerobatic capability as well as being a surprisingly smooth flyer.

 Overview and build video

 Beginner's aerobatics and slope flights

 Onboard views over Corio Bay on a lovely calm day

 SPECS

Armin wing span - 1.2m (47") 

Airfoil chord - 190mm (7") including 45mm (1.5") ailerons

Airfoil thickness - 23mm (12%) using 9mm formers 

Spar - Skyshark P4X 7.5mm x 850mm, 57mm back from LE

Fuselage Length - 700mm (27.5")

Flying weight (2200mAh LiPo) - 770g

Full span Ailerons / Flaperons

Full flying Elevator

Large Rudder

TGY 9018MG servos x 4 

Motor - Turnigy 2826/10 1400kV with 9x4 prop

ESC - Plush 40A

 MATERIALS and LINKS

 Newton Airlines Blog

 Underwater, Kites and RC Website

 
 

COMMENTS

Flyingninja on April 30, 2015
Do you have tiled plans?

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apnewton on April 30, 2015
Sorry no. I don't work from plans
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DaytonRiverRat on April 22, 2015
Great design. Love your control al low levels. Here in the middle of the US, I don't have a lot of slope soaring opportunities, you make it seem effortless (I know it isn't).
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apnewton on April 23, 2015
Ha, not always in control. Slope soaring is easier, seriously. The plane is always out front and mostly at eye level. You must give it go some time.
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flying panda on April 30, 2015
Simple and smooth, well done
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apnewton on December 23, 2015
Thanks flying panda
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KiwiRCFlyer on April 22, 2015
Really enjoy watching your channel. Very informative and inspiring.
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apnewton on April 23, 2015
Thanks Kiwi.
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HarleyRev on April 20, 2015
awesome plane ! Thanks for sharing !
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apnewton on April 23, 2015
It surprised me how smooth it was.
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Miracle Air on April 20, 2015
We'll done! Love it!
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apnewton on April 30, 2015
Thanks
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stormboy on April 21, 2015
That elevator design is clever. I would have never have thought of that. Great build video.
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apnewton on April 30, 2015
Very kind of you, thanks
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MOcchionero on December 23, 2015
Exceptional. Great plane... Super video... Very enjoyable. Thank you for posting.
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apnewton on December 23, 2015
My pleasure. I'm about to try a proper symmetrical airfoil on it.
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kellyboy on January 7, 2020
Great looking and simple little plane! I would have loved a bit of detail on laying up the wing. Is it all depron bent over with a former or 2 in the centre or CG point?? Well done from Qld, Australia.
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1.2m depron Acrobat build