As I mentioned, I totaled the first Predator UAV, due to the combination of an underpowered motor and the marginal controllability of that design's V-tail-only steering. I spent last weekend replacing it with a different Nitro Models Predator, which has ailerons. Unfortunately, that model is currently out of stock at Nitro Models (I had a kit I'd bought some months ago), but on the off chance that it comes back in stock and someone out there wants to build it right, here are some tips:

  • For the ailerons, you'll need micro servos like the Futaba S3114s. When you're threading the servo extension cables through the wing, wrap the connectors with tape and taper the wrapping into the wire, to avoid connector edges that will catch on wing bulkheads.
  • You definitely want steerable landing gear. There are a lot of good tips on how to do that in this thread. One of the things that stumped people was how to use servo mixing for the V-tail and still use the rudder to steer the nose gear. The answer is to use a VeeTail hardware mixer, with a Y-connector from the receiver going to the nose gear servo and the VeeTail input. The VeeTail board is also compatible with the UNAV PicoPilot autopilot, which we'll be using later.
  • I used a Hacker A30-28S motor with an 8x6 pusher prop. I had to use 1/2" spacers to get it far enough back to clear the fiberglass rear cover. And even then I needed another 1/4" nut on the prop shaft to get the prop far enough back to clear the cover. (BTW, if you use the Hacker you'll have to trim away an eighth of an inch around the open in the back of the fiberglass cover to clear the prop mount.
  • I made the wings removable. This involved putting little hooks in the side of each wing and drilling a corresponding hole in the fuselage on each side. A short rubber band, threaded through the fuselage with a paper-clip hook, keeps the two wing halves from falling off.
  • I put two spruce rails on the bottom of the plane, just ahead of the landing gear (ie, right on the center of gravity) , and put screws sticking out them at the front and back sides of each. This will serve as our payload attachment point, and the screws sticking out are for rubber bands. It fits our stabilized camera mount beautifully.
  • It remains to be seen how well the UNAV PicoPilot flies this plane. UNAV warns against planes with ailerons and little dihedral, which is the case here. Until I test it in autonomous mode, consider this just a very cool looking R/C aerial photography plane.

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Comment by Ahmad Usman on September 10, 2007 at 6:48am
Excellent work....

T3
Comment by icebear on September 13, 2007 at 3:54am
Chris, looking great - will be fin to see how it develops.
Re. the Picopilot and ailerons, I have one installed in my Viking which has huge ailerons and very little dihedral and it is working great.
I used a Veetail OMNI mixer to mix in some rudder with ailerons to create smooth coordinated turns.
If the plane is relatively stable I don't see any problem.
Just make sure it is setup to fly straight and turn equally right/left on rudder input and setup with very mild turnrate with an OMNI mixer and you'd be fine!
/Icebear
Comment by bobusia on November 6, 2012 at 12:10pm

Mam do was pytanie gdzie można dostać schemat budowy i zarysu wszystkich elementów ?

Bo chciałbym sobie sam z pianki taki uav zrobić.

Comment by sergio gamboa on November 19, 2013 at 9:43am

any can help me with the software for picopilot system?

Comment by sergio gamboa on November 19, 2013 at 9:43am

hello, I got picopilot system, but I have the software, someone could facilitarelo? thanks

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