Did some googling on military UAVs and it came up with this nice site, listing 30 UAVs currently in use and for future deployment.


http://www.popsci.com/technology/gallery/2010-02/gallery-future-drones

I found the inverted v-tails on some of them interesting, can anyone enlighten me on the advantages they present compared to normal v-tails or even more conventional tailplanes? I've seen one or two blog posts with similar mods, but it seems all it does is save weight.


http://uavkes.blogspot.com <- our blog


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Comment by Ryan on March 25, 2010 at 2:08pm
There isn't awhole lot of different between V-tail and Inverted V-tail. The calculation is the same. However inverted V-tail is slightly better for jaw control in coordinated turn.

The main advantage with inverted V-tail when in use with twin boom aircraft design is for structure rigidity and of course help with protecting "genius" from the prop, and give you a place to push the plane :)

That's a nice photo of the Shadow 200.
Comment by Mike Bakula on March 25, 2010 at 2:15pm
I agree with stikmunkey, inverted-V provides some pro-verse yaw. If you size the elevons and set the v-angle correctly, you can get coordinated turns with little or no aileron, for your design condition. (And the twin-boom setup really is safer.)
Comment by Andrew Burns on March 25, 2010 at 2:36pm
We're going for that layout in our design because:
- Twin boom pusher is safer to be around on the ground
- V tail has slightly lower drag
- No protruding cantilever structures (like fins) so it's stiffer and less likely to catch on things
- Keeps more of the control surfaces up away from the prop wash, at least the middle of the prop wash
- As you can see in that photo the top makes a good place to put antennae :P
Comment by Melih Karakelle on March 25, 2010 at 2:59pm
Standart V tails works like counter aileron and reduces aileron effect.
Inverted V tails works like an aileron and plane can turn perfect without aileron.
Aileronless design = removable and rigid wings.
Comment by Irfan Mohamed on March 25, 2010 at 3:45pm
Thanks for all the help, I'll definitely be considering this setup in a future project :)
Comment by Xander on March 25, 2010 at 4:12pm
So the V tail can function as the only control surfaces on the plane? Would that fly similar to a flying wing without any true yaw (roll and pitch to turn)?
Comment by Ryan on March 25, 2010 at 4:43pm
In theory yes - it works OK for small light weight plane but when you go to a larger platform, you would still want aileron to correct bank angle because there would be a larger mass (wing) to move around...don't think the ruddervator alone can give you enough response.
Comment by john bero on March 25, 2010 at 6:53pm
How does it do in a flat spin situation? I know the standard V tail configeration has some negative history with unrecoverability. Sort of an Urban myth. Anyone?
Comment by Ryan on March 25, 2010 at 8:20pm
At typical UAV high wing loading (all that I've flown so far), if your're in a spin which means your onboard INS, autopilot, and other systems had failed, then it doesn't matter what tail configuration you have - you'll be wishing for a ballistic parachute!
Comment by Firefly on March 29, 2010 at 4:26am
One of the big advantages I have heard in favor of inverted V tail designs is its stability in cross wind situations. For an example when hit by a cross wind gust on landing the inverted V will cause the airplane to pitch up as opposed to diving into the ground. It shouldn't make any difference when used with an autopilot but many military UAVs are remotely piloted during landing.

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