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Permalink Reply by Andrew c on April 29, 2010 at 5:22am

Having used the Raven before, it works pretty well in flight, though actually landing it is really just crashing it into something (usually the ground, via a stall)

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Permalink Reply by Tim McMahan on April 29, 2010 at 8:01am

You are a UAV pilot?? Why the need for deep stall at all? why not just belly slide? I made a solid foam mockup of the fuse last weekend for part templates. My concern is that it;ll be very tailheavy, unless I pack tons of gear into the nose. I may elongate the fuse forward a little, which will help out with the tail weight, as well as give MORE room for gear.

Thanks for the reply by the way!

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Permalink Reply by Andrew c on April 29, 2010 at 9:33pm

Nope, the Raven is a unit level UAV. I'm infantry, but each company has one, and a couple infantrymen that are actually trained to fly it. The rest of us just mess around.

I don't know why stall, but it's made to break into pieces (and it's all Carbon fiber, not too worried about breaking it). If I had to guess, they teach you to do it that way so you can land it without a suitable place to slide it. The Army isn't big on teaching different ways to do things when one way always works.

The nose is fairly heavy, with the only real weight in the back the 1.5-2" tube that goes back to the rear surfaces, and the surfaces themselves. Everything else is packed into the nose.

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Permalink Reply by Tim McMahan on April 30, 2010 at 5:01am

Thnaks so much Andrew. Its really great to get some insight from someone that has even worked AROUND a military UAV. I was suspecting the deep stall to be well suited for coming in through a hole in a jungle canopy, or between dunes, etc. I hadn't thought about uncle Sam's policies, now it makes more sense, LOL!
As for the center of gravity, I don't have a $20,000 FLIR thermal camera to put in the nose, just an Ardupilot. I guess I'll elongate a little bit, then add batteries or lead. ;)

Thanks again.

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Permalink Reply by Troy Reabe on April 29, 2010 at 9:28am

Both tractor and pusher work just fine provided you design for them
a pusher is more efficent than a tractor due to not having the high speed air running over the fuse. But having the the prop infront of control surfaces alowes you to have a poor mans vectored thrust. For a uav not having the prop in front is nice incase a person ends up in the flight path.

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Permalink Reply by Tim McMahan on April 29, 2010 at 9:35am

Good call, I hadn't thought about safety. I might also be rammng buildings, cars, who knows. I live in the midwest, could be livestock, LOL! Sure looks like the pusher is the way to go. With it being EPP foam, I won't give UAV's a bad reputation. Bummer too, the tractor looked easier to design. LOL! Oh well. Raven, here we come.

Thanks!

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Permalink Reply by Troy Reabe on April 29, 2010 at 10:12am

I was going to mention when doing a pusher like this with the prop in front of the control surfaces you are going to want to do power off control testing. you do not want what the lake amphib has for problems. the prop going right over the tail gives great control but when you cut or loose the engine you notice that you are missing the athority that you want. One plane that I think would be a fun UAV would be the Long Easy or the Velocity http://www.velocityaircraft.com/ I have seen RC models of the Easy but have yet to see one for the Velocity.

And don't be mean to cows, they can feel it when you hit them with a tractor :)

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Permalink Reply by Tim McMahan on April 29, 2010 at 10:19am

I have never hit a cow, nor would I on purpose. But it would be realy funny to see. LOL! I like the Long Easy, i have seen those too. Not sure what the difference is, buyt I like the velocity more. I may add that to the list, but it's got a few planes in front of it.

Thanks!
Tim

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