Orange Hawk Source Code - RC Groups
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Mar 19, 2013, 08:51 PM
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KatanaGuy's Avatar

Orange Hawk Source Code

The "Orange Hawk" used my modification of the MultiWii 2.1 opensource flight controller software and hardware architecture. I've polished the code and am attaching it here. The following pages will link to this blog post:
Introduction to the Orange Hawk Project (0 min 0 sec)

The attached ZIP file has the following text included with it:

Version 1.0 Released 19 March 2013

This Codebase is for the Orange Hawk VTOL Hybrid, released March 2013.
It compiles in Arduino 1.0 and Processing 1.5.1, using MultiWii 2.1 as the base code.
The Processing library controlP5-0.7.5 is used in the MultiWiiConf utility.

In August 2011, the author, Steve, decided to pursue a life-long goal of making a VTOL dream machine.
The goal was to create an aircraft capable of hovering and VTOL operations, but with the efficiency of
a fixed-wing aircraft. Inspiration for this project came from news clips such as the IAI Panther and
Mini-Panther, presented on YouTube such as this example here:
Panther UAV (2 min 10 sec)

Further, the author has been actively engaged in UAV design and experimentation for 9 years, starting with
electric R/C aircraft at age 13, and had concurrently attempted other ideas for VTOL aircraft.

Also, the efforts of "leadfeather", "cass3825", "foam and tape", "EddieWeeks" and "RCvertt" on the VTOL forum were inspirational. Although this group developed code based on MultiWii 1.7/1.8
for their efforts, I decided to forge ahead on my own modification of the more recent 2.1 version and try
to keep things simple. Their code is available in various threads, and a primary version can be found at, or at , cass3825's blog. I've modified the MultiWiiConf
utility for this code, and have other modifications such as a general purpose mechanism controler started.

The airframe I've constructed, called the "Orange Hawk" design, is a Tricopter Delta Wing with a Bicopter
front cassette assembly, which means that the front motors are actuated independently. Details on
the airframe itself, including the design decision, theory, motor selections, airfoil, and other metrics
are to be detailed in a AIAA Student Conference Paper to be presented at the AIAA Region VI Student
Conference in March 2013, and will be fully detailed after that date.

Information on the Orange Hawk VTOL design can be found at these threads as of 19 March 2013:

Thanks for you interest, and enjoy flying!
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Mar 19, 2013, 09:41 PM
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jjmelo's Avatar
subscribed! awesome work!
Latest blog entry: The 'Nocchio - 22" FPV Wing
Apr 22, 2013, 02:51 PM
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Darth_Elevator's Avatar
Wow, this looks so awesome! Do all three motors pivot for fixed wing flight or just the back motor? Either way, I'd love to see this in person. Are you going to sWARm next week?
Apr 22, 2013, 04:14 PM
Design, Build, and Fly
KatanaGuy's Avatar
You bet! I'm going to be there, might even put the O-Hawk up in the fray (within reason).
Apr 22, 2013, 04:48 PM
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Darth_Elevator's Avatar
Originally Posted by KatanaGuy
You bet! I'm going to be there, might even put the O-Hawk up in the fray (within reason).
Thanks, Steve, I wasn't planning on going to sWARm, but you've just given me a very good reason to try my best to make it down there. Good luck if you launch it into the fray.
Dec 18, 2013, 09:03 AM
Registered User
i have few doubts
1) why is the tail rotor-prop different than front ones?
2) can I use the yaw mechanism of tricopter design for yaw control of wing in forward flight(after transition)?
3) can i make the same model using KK2.0 board?
Dec 18, 2013, 12:39 PM
Design, Build, and Fly
KatanaGuy's Avatar
1) The reason that the rear prop is larger is because of the way I've distributed the weight. I intentionally placed about 50% of the vehicle weight on the rear motor, and the remaining 50% is distributed between the front two. As the front two motors are higher Kv, and therefore more efficient in forward flight at high speed rather than static thrust in hover, they have to be loaded much lighter, otherwise, the disc loading is so high that they enter the vortex ring state much like the V-22. The rear motor is optimized for hover only, and is inactive during forward flight.

2) The predecessor to the Orange Hawk was a tail pusher design I named the White Hawk. It used a 2-axis gimbal mechanism on the rear motor to both control yaw as a tricopter, and tilt for forward flight. I had the option to control yaw during forward flight when designing that mechanism, but decided otherwise, and so when it was tilted forward, the gimbal was in "gimbal lock", such that the motor was constrained to pointing straight back, no yaw coupling. As to why you would want to control yaw on a flying wing, it is not necessary if the wing has directional stability. Unless you want to initiate a side slip or have sufficient fuselage side area to generate sideways lift.

3) If the KK2.0 is still opensource (which I believe it is. I got my start with multicopter controllers with the KK1.0), then it should be modifiable.

Dec 21, 2013, 12:29 AM
Registered User
Thank you for your reply Steve.
Actually i already ordered 3 NTM Prop Drive 28-30S 800KV / 300W Brushless Motor (short shaft version). Will there be much difficulties in using all 3 same motor-prop?
Dec 21, 2013, 12:43 AM
Registered User
I asked about the yaw mechanism because i was thinking about a design that will eliminate the alevons and yaw and roll of wing will be controlled by the tail rotor in forward flight( keeping tail rotor in vertical direction only. Not in pusher configuration)
Dec 21, 2013, 01:14 AM
Design, Build, and Fly
KatanaGuy's Avatar
Ok, I see now.

For the yaw mechanism, that should work: It will require the motor to be kept rotating to some degree, I'd like to see how it turns out.

When I was getting the Orange Hawk's PIDs initially tuned, I placed it on a test stand as shown in this video:
Sneek Peak of the Orange Hawk (1 min 0 sec)
. I brought the vehicle to hover, with the rod participating a little as possible in the physics taking place, merely keeping the aircraft pointed straight basically. All three motors are KDA 20-22L's with APC 10x47 Slow Flight props. I flew the vehicle this configuration in all the first hovering and 50/50 flight tests, and only attempted forward flight once, and only once: In that first forward flight test, I knew the pitch speed would be low, but it was so low that even at full throttle, the aircraft could barely stay airborne and controllable, as the propeller-motor combination easily saturated at max RPM with only ~15 m/s passing through the disc(s). Hence, you can probably use 3 of the same motor, provided that the airframe can produce lift and be controllable at a low velocity. Or, with higher Kv motors, it would fly forward fine, but beware of high disc loading messing up the hover stability. (This is somewhat desired in the aerobatic quadrotor world, providing a smaller prop to the motor, allowing it to spool much faster, but aerobatic quads are pretty light anyway.... I don't know).

Hope this helps,

Mar 14, 2014, 11:22 AM
Registered User
rukie's Avatar
HI there, very nice project. I am currently looking at making one myself. But I do want it in the ardupilot or pixhawk. I am not a hard coder though.

Anyway where are you in this project? One question, do you maintain the other features of the 2.1 in this code modification? GPS hold? RTH?
Mar 18, 2014, 02:14 AM
Design, Build, and Fly
KatanaGuy's Avatar

Sorry for the delay; I would like to port this to the PixHawk, I've got an APM2.5 that I still need to unbox and get working. It's been hard enough to just maintain the 2.1 MW code, and now they are on 2.5 now! So, whoosh! Engineering it tough! I didn't get the GPS / RTH functions ported, although I'll be they will still work with the vehicle in Hover mode. In Forward flight, I'm still not at that point yet.

May 09, 2014, 05:46 PM
Registered User

Approach towards APM

How much success have you gained while working on the APM 2.5 or 2.6? at what point you are with your APM?
May 09, 2014, 05:58 PM
Registered User
Hey stephen,
Have you considered the option of using two different APM for the two flight modes (hover and fixed wing)? is it possible to use two different APM on a single platform?

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