Variable pitch Techpod

Hey everyone, Here is something cool that I have been working on that I think you may enjoy.
Variable pitch prop
So, I had been pondering how to make an inexpensive variable prop. I was thinking about using a heli head from a hk450 or perhaps a tail rotor. I eventually saw a post here, on diydrones, where a guy was using a tail rotor from a HK500 (can't find post). I got inspired and found a HK600 tail rotor has the same shaft diameter as the turnigy G10 I use on the techpod. this is what I have come up with.
I measured 15 degree max forward pitch and 12 degree reverse pitch. at 15 degrees forward pitch it drew 40 amps from a 3 cell lipo and puts out just under 5 lbs thrust.
I got the blades here and the tail rotor assembly here. I removed one side of the tail rotor plates and replaced both the shaft in the tail rotor and the shaft in the motor with one long 5 mm shaft. I had to notch it a few times for the set screws.I then made a plate to help support the rotor plate so I could then brace it with some 4-40 all thread rod and nyloc nutsI also made a custom motor mount for the techpod.
After the motor was secured, I cut out a mount for the pitch servo. Then I cut a hole in the foam so I could attach the servo mount to the techpods rear fuselage brace. I grabbed a bell crank from the local hobby shop and mounted it to the rear brace as well.
I have the techpod mostly assembled and should have the batteries for it later today. I hope to be able to start test flying over the weekend. If everything works out well, I plane on offering this as an mod kit for the techpod.

Check out this and the latest techpod news at Hobbyuav.com

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  • Moderator

    Wayne, I love the Techpod, wish I could buy another plane right now... (if I did the wife would...)

    I wonder how it would compare numbers to say this one: http://www.hobby-lobby.com/evp_pro.htm


  • Maybe a curved blade like from a fixed pitch helicopter or some blades from a folding type prop could be adapted.
    I honestly wouldn't expect any benefit on a plane this small/slow though.

    The other issue is electric motors don't really have the power curve to benefit from a variable pitch prop.  You can have a bigger prop for more static thrust, and the load will decrease in flight.

    The ability to feather them would be neat to reduce drag though.

  • 100KM
    The blades I have on it now are just for experimenting. I would like to find or make an APC type blade.

    No the blades dont feather. They dont go to 90 degrees. I would also like to see a hollow shaft set up.that would be much more compact.

    Being able to tune the pitch mid flight for climbing or cruise could lead to better efficiency.
  • MORE blades... :-D It would add so much weight/complexity that the gains wouldn't be much, but the wow factor.. 

    6 Blade Tail rotor - cnchelicopter.com

    I'm curious if this could be used like a folding propeller, and reduce the drag when motor is not needed??

    Looks cool..

    Also like Josh said, slowing is down to make a short landing would be pretty sweet too..

  • I think reversible ESC is much more reliable.

  • Throw it into beta for a short field landing?
  • Interesting development.  What do you hope to gain from this vs. simply using FP props?  I think you may find these are less efficient, but I'd like to see what your testing shows.

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