FreePilot Pre-Maiden Status


Hi Guys,

Its been some time since I gave any public updates to you people (contributors have got weeklies) on the status of the FreePilot project. Now as the project nears completion, I am posting photos and the current status for you people to comment on , advise, criticize , etc. I have run into some issues, most of which have been solved, but still need some help on the others.


  • All body work finished except canopy.
  • Everything bench tested.
  • Some ESC issues (summarized below)
  • XBee joystick control perfected.
  • Latest ArduPlane 2.5 (with modifications) loaded.
  • Battery and voltage sensor connected to APM on-bench.
  • Airelons tested to breaking point (still works perfectly)
  • Custom control rods attached (flexible plastic)
  • On the inside, spruce spars in original design replaced with fiberglass.
  • Everything else to get it flying.

To Do and Issues:

  • Make the canopy (almost finished)
  • Fix ESC heating issues: The 20A JDrones ESC is overheating on bench, without the motor running and just APM drawing from the BEC. My battery is a 11.1v 25C 2200mAh Turnigy pack, which should be suited for the ESC, but it still heats up, even after adding a beefy heat-sink on top. The MOSFETs on the bottom cannot be touched after a minute. I think I need a beefier ESC.



Heat-sinked ESC (which still gets too hot)



Just-arrived Turnigy LiPo recessed in the body


APM, GPS and Xbee recessed in the body


Servo connected to right aileron using my 'specialized' push rods


Top View without Canopy

Let me know what you guys think, whether it will it fly or not, etc. 

If you want a photo-log of the entire project, its down below :

Parts Arrived (courtesy of Martin)

Electronics Assembled

Airframe 1

Airframe 2

Battery and Charger (courtesy of Sandesh)


If anyone is interested in contributing towards the advancement of FreePilot please PM me!

This project would not have been possible without the generous contribution of :

  • Sandesh (for batteries and charger)
  • Martin (for APM, servos, Xbees, Motor, ESC and more)
  • Crasher (ESC and motors pledged)
  • Jaron (for airframe design which I have modified to suit my needs)
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  • Moderator

    You're right, they have poor lift/drag ratio, perhaps the intention was never a KF airfoil?

  • I know the KF airfoils and made few planes at the past with these frames but KF works on very tiny wings under very low wing load and drags a lot.

  • Moderator

    Wing looks like a Kline/Fogleman wing ( hence the weird looking wing form, but yes thick trailing edges are not advised.

  • Hi Mohammed,

    I guess you have to learn the aerodynamics before making your own frame.
    Wing form looking weird and very thick. Your flat back ailerons will generate big vacuum (wing form too) .
    Did you tested your plane without any electronics? It must be glide smoothly before motor flight.

  • 1. Your control horn setup looks wrong, see the diagram attached to correct it.

    2. Why use plastic for the control rod when a piece of wire with bends wil suffice

    3. What is the thickness of the ailerons?, they seem extremely thick and might provide a lot of additional drag3692489367?profile=original

  • Moderator

    Swept flying wings need their CG very far forward compared to conventional aircraft, with your battery where it is AND the motor at the rear the CG is going to be way too far back.

    Do you know how much current you are drawing? Also what is the weight of the plane?

  • I fly a similar plane and esc but I have my ESC in the airflow. If you mount your esc more on top (in direct airflow you should be fine).

    As far as your Control horns are concerned - This is something that you should really fix. The hole of the control horn needs to be exactly on top of your Hinge-line!

    Here are a couple pictures:

    or this here: (look for control horn installation)

    The Plate with the three holes in it that is just connected with a stub to your control horn should be cut of and is meant to be used as the bottom plate mounted on the opposite side of the control surface to stabilize your control horn. Check out the pictures!

    Aloha and good luck the rest looks great!

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  • Developer

    @ Greg The hinge point is in the middle of the sheet used to make the elevon. Could you please explain you angle thing. Sorry for being nooby.

  • Developer Will it be enough? Is it a switching mode one?

  • You need to look at the angle between the rotation point and the end of the arm. The one for the controlled should be parallel to the one for the servo. The angle for you controlled is way off. There should be no flexing of the control link at all. Every thing should move freely. Is your hinge point on the bottom or top of the wing surface? Control reliability is everything. With out it you will surely crash.

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