T3 the Vertical Horizontal one


This one should be easy if you have any of the current crop of Kickstarter VTOL airframes, of course I will award less points so you might not win.

The task is simple.... (not)

Auto take off

Autonomous hover for at least 1 minute after take off

Transition to winged flight and fly no higher than 120m

Then circle radius 80m for as long as you can. (This makes the circle 500m a turn)

This of course points to the current delivery drone mania. To get noticed by Amazon try for greater than 24km about the distance their machine can deliver (apparently)

We will make this a six month contest as its hard. On the plus side its building time in the Northern Hemisphere.

For extra points some sort of silly cargo that makes me smile. Super bonus points added for an autonomous vertical landing as well. (All landings to be vertical)

If you can make a multirotor fly that far then all well and good, but I will be looking for the least amount of power used in event of a draw. 

The longest distance wins.

Good luck, I look forward to May 2nd 2016 and the fruit of your labors.

Glittering prizes TBA

Let the pointing out of my Swiss cheese thinking commence...

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  • Hmmm, no other entries or tests yet?

  • Developer
    Mhh I smell real DIY spirit :) thanks for sharing your work!
  • Developer

    For those you want to try a QuadPlane for this challenge, some docs here:

  • T3

    I all, we are thinking about an entry, fortunately that there's still some time left, it is going to be hard.

    See you soon

  • Yes, thanks Rob.  Just can't bring myself to get into bigger R/C heli's, but you may change my mind.  I flew CH-46's, which get's rid of that nasty tail rotor.  Makes me want to create a tandem rotor BBot variant.  Never enough time.   Great info on the ESC's.  We will need to compare.

    And thanks again to Gary for picking VTOL for this T3.  It's apparent that people have some cool ideas.  I can't wait to see more data when they start flying.  We have managed to try a few different designs but never get enough time to test them well before we are on to the next project.


  • Thanks Rob for sharing all this info. Didn't know either and was surprised that  ESC's could make a difference in efficiency.

    I think you've made a very convincing case, both theoretically and practically,here and elsewhere,  that helis are simply more efficient than MRs in general. And your case for helis behaving better in wind that MR's is also compelling. In that regard, I wonder how an MR with tilt rotors would perform ... along with difference in efficiency in hover vs forward flight ... Haven't seen any info on efficiency of MR in loitering vs forward flight, and speed vs efficiency ratios, btw. I hope this competition will shed some light on this.

    That said I don't think a heli (and a fortiori MR) stands a chance against a fixed wing (with just 4 light rotors for VTOL just to take off and land, when it comes to flight time or flight distance switch to forward flight with a good mix on the controller)  You just can't beat aerodynamics and the physics of wing lift ... just consider that Maynard Hill 12 years ago crossed the Atlantic (1800 miles) and before that had flown as long as 38 hours with a model fixed wing. ok, it was with gas engines, optimized, etc ...  but I am sure you'll agree that any current  heli or MR cannot come even close to this. Adding the weight of rotors, escs, etc ... for necessary VTOL would certainly reduce performance, but would still make it a slamdunk for a fixed wing.

    That said, great competition, and let the fun begin!

    Btw, it may be good for this round to be a bit more precise on "extra points" Re: payload. Weight makes such a big difference ....


  • Rob

    Great comparisons as usual!

    But I'm wondering how your quad would perform if you would add a pusher prop and motor to the rear for forward flight. I'm guessing some 20-30% better. Even better if you add some little wings...;-)

    I'm hoping to post some VTOL flights over Christmas when I get some hobby time.

  • The new helicopter designs don't have that many small parts.  Check out the Goblin 380 design.  Elegance in Simplicity.  It doesn't even have adjustable swash links.  Just molded single piece.  There are exactly two adjustable links on the entire thing.  Now, imagine that thing with no tail drivetrain. ;)  Helicopters can be very simple.  They just don't get much development work anymore because they are old.  Everybody wants to work on the new hotness. ;)

    Check out the HobbyWing XRotor ESC's.  They are the most efficient ESC's on the market.  I was already a big fan of HobbyWing because of their quality and reliability.  I didn't know there was really any efficiency difference between ESC's, but then I stumbled upon this:

    I have promoted their use to other people, and everybody who has used them has been happy.  That includes some people with very large multirotors who have struggled with some "high end" ESC's.

  • Always interested in the details Rob.  Very interesting data.  We are also running KDE's.  A bit of a mix right now until we settle on a good power setup.  Right now it looks like BBCopter will work best with the 475kv and 14in props at 6s.  Should handle 10 pounds without real issues.  Just got a flight report back from one of our partners and they got 22 minutes out of that setup at 11.5 pounds running a 10,000 6s.  But again mostly hover work.  What we do not know is if the "fuselage" of the BoxBotix has any real benefits for forward flight in terms of drag reduction.  Easy to compute the wetted area of our design but might be a bit hard to compare to a more traditional quad frame.  I guess the proof may be in the pudding as they say.  My guess is we may need to spin closer to 24in props to get anything close to a the kind of times you are getting with a trad heli.  The irony is, I am an old helicopter pilot, and I have no interest in building and maintaining a heli.  Too many small parts for me.


  • Ok, just did a back to back test of the two machines.  That's the1530g Tarot 660 quadcopter with 15" props, and 2 4S 8000mAH Multistar 10C batteries, with NO payload.  And, the 1680g Protos 500, with a 200g camera, and the exact same batteries.  Both machines flew the exact same mission at the exact same 15 m/s speed.  Here's the trick though.  There was a light wind, about 15-20km/h blowing.  You can really see the effect of this on the quadcopter. Each graph contains 4 laps, and you can see the large power increase on the quadcopter flying the upwind legs. The helicopter was much less affected.  If the wind was even higher, the difference would be even worse.  In fact, the quadcopter was using 100% throttle on the upwind legs.  The helicopter was also using 100% throttle, but... not really.  I run minimum rotor speed, which can be increased when needed.  Last week I flew the same flight plan in 40 km/h winds without problem.  The helicopter allows the easy ability to tailor the flight power to the requirements.  In fact one thing I'd like to add soon is automatic variable rotor speed according to requirement. 

    Overall, it's pretty clear which machine will be able to cover a greater distance. The helicopter probably flying almost twice the distance if you were to add the same 200g load to the quadcopter.


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