I've been working on a new helicopter platform the last few months. Based on an MSH Protos heli which I chose because it's an extremely light weight platform, weighing in at only ~1200g without battery. It has a full belt drive which I much prefer to gears as it's quieter, lower vibration and more reliable. I've had a few problems with it because the belt drive makes a really awesome Van deGraaf generator... not a good thing on a UAV. But I solved that, and am conducting test flights now.

The flight controller is a modified PX4v1. I replaced the switching regulator with a MIC29300, so that I can run it on 2S direct with the servos. Main motor power is 4S 5000, typically this heli would run on 6S 3300. Using the MSH stretch kit and 465mm Spinblade Asymmetric blades. In otherwise standard form, this heli flew for 17 minutes on an old crusty battery, in -10C temperatures.

I have now added a subframe to hold an extra battery, FPV gear with a camera in the nose, and a vibration damped NADIR camera mount to be used for aerial mapping. The idea is to develop a mapping UAV that is superior to a multirotor, offering a valid alternative to a fixed wing for short to medium range missions. The VTOL capabilities would eliminate all the nastiness of catapults, and controlled-crash landings with onboard cameras in rugged areas.  Even the price is attractive at about $400 for the basic kit with motor and ESC (no servos).

Specifications show the advantage of a heli platform. This machine has an AUW including the batteries and camera of only ~3kg. It is 80m long, and about 15cm wide not including the extended legs, and 30cm high. The blades fold for easy transport, without requiring any lose wires or vibration-prone electrical connectors as a folding multirotor does. It actually looks much bigger on the table than it really is. This seems to be very good compared to multirotors I've seen with the same performance. (payload and duration)

Vibrations are always a problem with helis, but manageable with the right design and construction techniques.


Arducopter really makes helis worthwhile. You could buy two entire heli systems including a Tx for the price of a single DJI Ace One non-waypoint controller.  Or 7 for the cost of a single Ace One waypoint enabled controller.  I strongly prefer the PX4 controller over the APM and Pixhawk, because it offers 32-bit performance in a small package that is easier to mount in a heli frame.

So does it work? I took it up for it's first photo tests yesterday, and it worked beautifully. Better than 80% photos are usable. It flies for 20 minutes in a hover with old, cold batteries (-5C). I'm hoping for closer to 30 minutes while actually moving (helis are more efficient moving than hovering), in warmer weather with new batteries.  It should have an easy cruising speed of 15 m/s with little or no reduction in flight time.  At 20 minutes, this would offer an 18km range, and 27 if it can do 30 minutes.  If you wanted to do FPV and not mapping, you could configure it with a 3rd battery in place of the SX260 and fly for... 30-45 minutes, and a range of up to 36km.  Top airspeed is still TBD, but probably 20-25 m/s.  

Wind penetration and stability is excellent compared to both multirotors and fixed-wing.  You could do a mapping mission in winds up to 40 km/h with little effect on stability or duration.


If the success continues, I'm going to consider building a large gasser heli.  This would allow flight times up to 2 hours, or payloads on the order of 10 lbs for 30 minutes.  So you could map large areas, or even perform light duty spraying operations.  I'm thinking about local application of a herbicide for things like Giant Hogweed elimination, that sort of thing. Such a large heli does pose significant danger and should only be used in industrial, agricultural or remote areas.

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  • Ok .. That didnt go so well ... The moment the heli got off the ground .. Crazy left to the ground ...

    I took the gaind for pitch and roll down from what was defoults .. Also in mp the vibrations stayd under -1 ... Also was very carefull .. But could not save the blades ... :(

  • hi

    i am failing to understand .. sorry .. but the manual ( and you david ) talk about mode_1 ..

    i dont have it ! 

    i also dont have full param list ...



    about channel 8, well .. i can move the collective without arming but not run the motor so i think it is safe enough .. 

    looks like time ti try outside .. when the wind will settle a bit. 

  • Guy,  If you are using RSC mode 2 then the input to APM 8 should not move. It should be either high or low. Try this.

    Channel 3 to 3, 6 to 6, 7 to 7 and 8 to 8. Next with channel 8 in a low output position arm the system. When it arms move the left stick a little above its bottom position. this will prevent the system from disarming after a period of time. Next switch your gear switch (CH8) on.  With in 5 seconds or so your motor should start to rotate and speed up to its setpoint.  Again, NO PINION on the motor shaft. 


    David R. Boulanger

  • thank yiu david :)

    i dont havve the full param list in this heli installation .. i dont know why.

    when i connect the hexa copter i do get it.

    i updated the MP to last ver. and i got the ch8 in the rsc !

    but i am puzzled about something.

    ch8 of the rx is connected to ch7 on the apm. so the gear sw is activating ch7 .. the ch8 is where the throttle connected ( ch3 of the rx ) so when i pull left stick up ch8 is moving .. is that the way it should be ?

    i need to disconnect the rx from apm to reflash it .. usb will not connect while rx is connected .. i will do that tomorrow.

    thanks for the support !

  • Robert, thanks for the encouragement and the update on 3.2.

    My HK 450ProV2 FBL (and associated bits) is sitting in Vancouver clearing customs as we speak (type?) and I've got the Pixhawk+GPS sitting on my desk waiting for it all to arrive. I'm really pumped to get started on this build! I just hope my schedule leaves time to get this done.

  • Guy,  I'm glad you are making progress.  I still think things may not be set up properly. Be careful.  Have you looked at all your parameters in the full parameter list in mission planner?  They are all explained reasonably well in the wiki.


    David R. Boulanger

  • wow !

    only removed the corve from ch6 .. and everything is working incl. arm !

    i still dont understand why :) ..

    but in MP, the rsc is still empty.

    i think i will reflash and install new MP

    thank you so much !

  • Guy, Channel 5 looks good.  It looks like you are using a pitch curve coming out of 6 into 3 on the APM. This is where I think you are confused. Your left stick that is usually throttle on a airplane is your pitch. Try 3->3 and if you gear switch is channel 8 then 8->8. Take your pinion off the motor before you test any of this.  If you have done all your radio calibration right You should be able to arm by holding the left stick down and to the right for about 5 seconds.

    But again, There should be no throttle curve and pitch curve coming out of the radio. It should be in airplane mode or ACRO as some radios say.

    I am not familiar with  the er9x. I am just trying to help the best I can.


    David R. Boulanger

  • Hi David.

    thank you.

    the MP ver. is 1.2.97 build 1.1.5167.24804

    the apm ver. is : arducopter v 3.1.3 ( on terminal page )

    i guess i am missing something big here ...

    all the right side of the heli settings in MP the pull down menues are empty, nothing to select there ...

    the channels from the rx to the apm are

    1 -> 1

    2 -> 2 

    3 -> 8 

    4 -> 4 

    5 -> 5

    6 -> 3 

    7 -> 6

    8 -> 7 

    i got it from the picture on this page:


    there is a table also under the picture, that say ch8 shoud get the throttle ( input ) so i guess i should set the radio to give thr to ch8 ? 

    my radio set that way:  (er9x )

    4 channel trainer plain

    ch1 -> 100% ail

    ch2 -> 100% ele

    ch3 -> 100% thr ( throttle )

    ch45 -> 100% rud

    ch5 -> -97% id0 ( mode stab )

    ch5 -> -48% id1 ( mode AH)

    ch5 -> -15% id2 ( mode loiter)

    ch5 -> 17% ail( mode rtl)

    ch6 -> 100% master:ch3 curve (-30/-10/30/60/90)

    ch7 -> 100% knob3

    ch8 -> 100% gear 

    ch6+ch7 are advised in the wiki to be used to trim the craft and save the setting in air 

    ch8 is the trigger for the motor run ( as i get it ... )

    can't find how to arm the heli ( other then the button in MP )

    if i did not understand correct .. please correct me :)

    thanks !

  • Brian, don't worry about what Denny is saying.  He's just trolling because he's upset about me calling him out earlier. 

    I'm not offended by his comments because I know for a fact our code is better than all 3 of DJI's offerings, which are virtually unsupported now (apparently you can't even find a Naza-H for sale anymore?).  And then it's in a completely different class from Skookum and the German systems.  If somebody thinks those other systems suit their needs better, they are of course totally free to use them.  But Arducopter is the ONLY system that brings true UAV functionality to Helicopters at an affordable price.

    And just a reminder that 90+% of the code for helicopters is EXACTLY THE SAME as used on multi-rotors.  The only difference with helicopter code is some of the functionality (ie: Ch8 motor start, etc.) and the flight dynamics.

    And I'd like to take this opportunity to say that I think it's a fair statement that the flight dynamics code in Acro mode for Pixhawk with the 3.2 release will be at least as good as a mediocre FBL controller, if not the higher end ones.  But then will also have all the same UAV functionality you've come to expect of course.  I've made a good bit of progress on the dynamics front and I'm pretty happy with where it's at.

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