The design for this lightweight aerobatic slope soarer was inspired by a DLG or discus launch glider. I wanted an ultra light sloper that would fly in very light winds and on small slopes.
Plan, specs, materials list, build and flight videos below.
There are a few unusual design features in this build.
Rudder and elevator are operated by a pull line acting against a torsion spring glued into the hinges. This means there are no pushrods along the tail boom and servos can be mounted well forward in the fuselage pod.
Torsion springs bent from 0.4mm SS wire
The trick is to make a torsion spring strong enough to operate the control surface against the airflow but not so strong as to overpower the servo. The 0.4mm SS wire provided as pushrods for the Versus DLG turns out to be perfect.
Glueing down the torsion spring on the elebvator hinge line. ID card plastic reinforcement.
Tensioning the pull line. (150lb Kevlar kite line)
The Armin style wing is 6mm depron covered with 43 micron iron-on document laminating film (sometimes called "New Stuff" by the RC community)
More glue needed here (So I discovered on a hot day!)
This is a great aerobatic sloper and will work in anything over 5kn on a decent slope. In 10kn it will work on any slope. In 20kn it's very exciting but takes some skill to stay in control.
Dimensions (Sketchup file available)
SPECS
Wingspan - 1.5m (65") Armin wing
Length - 104cm (38")
Flying weight (500mAh LiPo) - 410g
Ailerons
Elevator
Rudder
TGY 9018MG servos x 2 (elevator and rudder)
HXT900 servos x 2 (ailerons)
MATERIALS
6mm depron
43 micron laminating film
60 micron clear packing tape
2 x Skyshark P4X spars (7.6mm x 820mm)
- Wing spar 820mm
- Tail boom 700mm
150lb Kevlar kite line (pull line)
0.4mm SS wire (torsion springs)
Soft packing foam (nose cone)
4mm CF rod (wing tie down bars)
Overview and build video
Aerobatics in 10kn
Gliding on a 4m rock slope (dihedral wing)
VERSION 1.1 adjustments
After extensively testing VERSION 1.0 (above) a few issues showed up. The cut-out ailerons meant there was only a small amount of hot glue holding the sub trailing edge of the wing together. On a hot day the glue let go and the wing opened up along the aileron hinge line. I needed to reglue and tape along that area. At the same time I extended the ailerons to the wing tips for better aerobatic performance.
Due to constant pull from the springs the rudder servo started to lift out of position. Extra foam bracing and glue was added around both servos.
LINKS
Bulk Depron - http://www.tradewarehouse.com.au/more/depron-foam/white.html
Skyshark P4X spars - http://www.kitesandfunthings.com/ProductInfo.aspx?productid=SSP4XCAM0
New Stuff iron-on film - EZload laminate - GBC Australia
Blank ID cards - Ebay http://www.ebay.com.au/usr/y2store?_trksid=p3984.m1439.l2754
Newton Airlines blog (Plans) - http://newtonairlines.blogspot.com.au
Website - http://anewton.net
UPDATE 21st Dec 2014. More aerobatic action with full span ailerons and some beach level sand skimming.
0 comments