Dual Prop Sport

Fun little plane: quickly launches into the air and is able to turn on a dime with snappy rolls and loops.   The 40" wings make it easy to throw in the back of the car.  Unlimited vertical with up to 2200mAh battery, and accelerates upward with a smaller 1300mAh.  The second motor makes for a slightly more complicated to build (more soldering, etc) but the added benefits makes it totally worthwhile.  Bonus features include detachable landing skiis and wheeled spring suspension landing gear.

Great for small plane FPV!!

Drawings, stl files, and added assembly instructions after learning from four iterations of this plane over the last year.  Now easier to assemble to get out flying sooner.  Optimized stabilizers for improved tracking during loops and landing.  All dimensions in fractional inch sizes for easy transfer to foam board (no need to print plans).

Specs:
Width: 40"
Length: 30"
Weight: 450g w/o battery
Center of Gravity: 2.0-2.25" behind wing leading edge
Flying Time: ~10 min

Step 1: Assemble the body
Link to 3d print files: 
  -  print "DPS_Chassi_3_holes": SLA, .2mm, 20% infill
Link to foam board plans
Link to assembly instructions

Step 2: Assemble the wing

Link to 3d print files

Links to standard wing: (best performance, easiest build)

    - Standard wing (v1) ailerons

Link to assembly instructions

Armin Wing schematic: (check out Experimental Airlines YouTube for more info)

Alternate wing options:

    - Standard wing (v1.1), flaps and ailerons

    - Flared tip wing (v1.2), flat with 4" flared tip

            -  Improved roll stability recommended for beginner pilots

    - Slight dihedral concept: added complexity, slight roll axis stability with limited impact to performance

             - adds ~1 deg. upward wing angle.  More complicated build

             - use any wing plans, use eight .75" foam spacers instead of four.

             - position wing stiffener over one layer of foam in middle of wing, and under at ends.

Assembly Tools Needed:

• 3d printer, SLA filament
  
• Razor blades
• Yardstick, with 1/16" increments
• Right angle
• Foam board, 5mm/.2in thick (dollar tree foam, or Flightest)
• Wing stiffener (optional), hollow carbon fiber 5-6mm square or round, 1M length (or wood dowel)
• bamboo skewers or 3mm carbon fiber rod
• Hotglue, with foamtac  and 2-part epoxy a nice to have option
  
• tape: packing tape, hinge tape (or here), etc
• Soldering iron, solder
• heat shrink to cover solder joints
• velcro

Electronics Needed:

• Battery: 1300-3000mAh 3s (2200 best for all around use, 1300 has best vertical climb), example
• 2 Motors: X2206 1500kv Sunnysky (18g) or similar with ⌀31.5mm 4-hole pattern
• 2 ESC: 10-20A, 1-2A ESC, 21mm max width, example1 or example2
• 2 Propellers: Turnigy Slowfly Propeller 7x3.8 Black (CW & CCW)
• 3 Servos: 9g (2 aileron, elevator) example1 or example2
• Receiver -  4-6 channel (6 ch for differential thrust or rudder)
• Servo extension (2 @ 6-12")
• Motor wire (18-20ga) and battery connector

Photos:

FPV with optional skis:

Spring Suspension Landing Gear

Updates:

09-June-2020 updated plans

Photos:

Wheeled spring-suspension landing gear - entire setup under 90g
  - using 3" lightweight wheels
  - better tracking over rough grass fields and not-so-soft landings

Wheeled Spring Suspension parts:
 - Brass tubing (5/32, 1/8"), cut to length as needed
 - Springs, 2" L, .025" OD, .023" wire diameter (up to .025" should work, found in local hardware store)
 - fishing line (10#, or similar)

 - Wheels,  3" lightweight wheels shown

Updates:

09June2020 updated plans, added assembly instructions

27April2019
- Added photos and stl file for wheeled spring-suspension landing gear

30March2019:
 - Version 2 completed, wing and fuselage drawings updated.
 - With the snow melting, rubber-band suspension wheeled landed gear tried out, needs work!

Fall 2019
 - Added spring suspension landing gear - works great!