Has antone seen this

[lenniegordo]

http://veratech.aero/phantom.html


WHAT da!

[rob10000]

yup, right here!
http://www.rcgroups.com/forums/showthread.php?t=575120

[CrashingDutchman]

I couldn't watch the movies on that site???

[mikel]

what about this one?

http://www.defensetech.org/archives/002815.html

http://www.flightglobal.com/Articles/2006/09/05/Navigation/196/208824/AUVSI+VTOL+rivals+line+up+for+unveiling+.html

[Tom Harper]

It was posted here a while back, but this time I watched the vids.

It's an interesting idea. It looks like the CG is at the junction of the rotor and the motor booms. But the motor alignments are wierd.

Does anybody have a sketch of how this thing is rigged?

[Unterhausen]

I still haven't figured out how they keep it from spinning out of control. I'm not sure it's useful, but I have a lot of respect for these guys.

[Tom Harper]

They are after DARPA funding. This thing might get some $$$.

I agree - definitely an accomplishment.

[TheKnife]

It ("invisible" UAV) seems similar in concept to this semi-complete RC flyer, the Maple Seed (http://www.tcrobots.org/members/rjesm.htm#robot7) (kudo's to quax for the find). I also wonder about the motor alignments as my first thought would be to make the motors push or pull at right angles (tangentially) to the spin (like a tip-jet heli) so as to maximize the thrust. Both the UAV and Maple Seed have what I'd think are offset thrust angles ... perhaps for some lift before the vehicle is totally up to spin speed ? Got me. :confused: I don't think either vehicle has full flight controls at this time. Both were/are more of a demo of prinicple type of thing. Given it's basically gyro stabilized I wonder if a cyclically operated flap on the "blade" part wouldn't give it lateral flight control ?

[thewz]

Given it's basically gyro stabilized I wonder if a cyclically operated flap on the "blade" part wouldn't give it lateral flight control ?

Maybe it uses differential thrust to alter the flight path?

It's got to have a decent electronics package...ever tried to control a heli under power after you lost the tail?

I wonder what it will be used for and why it would be considered over a basic low pitch high RP coaxial…

[Unterhausen]

the maple seed makes the offset thrust angles more obvious to me. You need downward thrust just to balance the weight of the wing. Now I gotta figure out what the upward thrust angle of the other motor on the invisible uav is for. Actually, i was thinking it could be a pusher prop.

[TheKnife]

I'm not sure I even really know what the orientation of the motors truely is. When I look at the "product brochure (http://veratech.aero/pdf/Phantom%20Product%20Sheet.pdf)", the folded-up depiction seems different from the depiction shown at the top of the brochure. The latter looks like what's shown in the "soldier's" hand on the website but then when I look at the first few frames of the 2'nd video I'm back to thinking the folded-up depiction is closer to truth. :confused: I'm not sure what is an artist's sketch and what is an actual picture or CAD drawing or some early mock-up.

EDIT: Just got a chance to re-read the other thread on this thing and the picture taken when it was shown at AUVSI looks more like what's shown at the top of the brochure. Aaargh ! Now I'm left wondering just how much of the UAV's weight is supported by the spinning blade and how much by the props ?

For the moment it looks to me (going by the folded-up depiction) that 1 prop is aligned like I think it should be, a pure pusher (or maybe a puller). All it's thrust goes to spinning the UAV. The other prop is offset so it seems to push up/down on it's arm, contributing no thrust to spinning. I think you maybe correct in that this is lifting the part of the UAV which is opposite the blade, and across the rotation center. It doesn't appear the either motor arm contributes much lift and gravity will want to pull these down. The blade lifts itself and want to tilt since I imagine the tip make more lift that the part near the rotation center. Pushing/pulling by the "wierdly aligned" motor might keep the blade part horizontal so it can deliver all it's thrust downward to make lift. Makes you wonder if 2 blades, each with a motor at it's end and connected via a "small" tube might have been a better solution ?

To answer "thewz's" questions - They bill it as a camera platform that's hard to see because all of the UAV is in rotation. So just like it's hard to see a normal heli's blades when they're rotating, it's hard(er) to see this aircraft vs a heli whose body (when hovering) is just sitting there to be seen. Not sure how big a difference it would make in real life but it's pretty cool anyway. :cool:

EDIT : To answer your other question, look at the links in the other thread to the patents online. Amazingly they change the RPM of the motors during a cycle to produce flight control. I wouldn't have thought this would be fast enough to be effective.

[thewz]

To answer your other question, look at the links in the other thread to the patents online. Amazingly they change the RPM of the motors during a cycle to produce flight control. I wouldn't have thought this would be fast enough to be effective.

That's cool! That's what I was thinking when I said differential thrust. I am surprised that it works. The impulse must be huge since it appears to be at about 700 or 800 RPM's…

I need to read the specs…

[Crusty]

Egads!!!!, I really have to ask WHY?, they mention a camera, but I can find no info on how they intergrate it or if they have even tried.
as for the invisibility claim, ...I watched the video, ...I could see it quite clearly and presume the pilot could too (unless he was just pretending to control it)
though in all fairness it is low observable

the claim of rc and gps compatible is weak...any plane, heli, boat, car
with enough room is rc or gps compatible

No data on performance at all...this is what counts to a customer..performance

[dalbert02]

I saw them at Unmanned International conference in Orlando a few months back.

http://www.rcgroups.com/forums/showthread.php?t=538447&page=2&pp=20&highlight=unmanned

As the camera in the center spins, a ground based computer takes the images and stitches them together to create a 360 degree view. Pretty cool. :cool:

-dave

[Tuner]

It seems the motors are orientated so when equal power is applied the vertical component of the 2 thrust vectors cancels out leaving a thrust vector that is parralell with the blades witch spins the craft. It seems they have their torque canceled out as well. If you create a differential between the two motors it twists the craft both with torque difference and the vertical thrust vectors not being canceled anymore. This differntial power I would think would need to be pulsed at the certain points in its rotation (usiing a gyro as reference). If it were applied constantly the craft would not tilt on its axis rather it would just wobble or flip out!

Just applying my commons sense though Im probably way off???

Everything they talk about in this design is very Possible.
But this is going to be a B##CH to control.
With a line-scan camera you could easily generate 360 degree panoramic photos or video even!
I just think this will be a long time comming for commecial use as the control sensor and software will have to be powerful.

I love this design, whats great is the physical design is so simple where all the complexity comes in is the controls.
My 3cents