Comment by fibrewire on July 20, 2011 at 12:25am

When I say large blades, I mean blades that serve the same purpose as an airship. So these blimp-blades would be covered with photovoltaic film, would make the variable-pitch quad rotor extremely light, and make it possible to cruise high altitudes practically and indefinitely. The blades could charge the vehicle's electronics and power the onboard electronics. A quad-rotor airship...

Comment by Coptaire on July 20, 2011 at 3:02am

If the control surface impacts the airflow in this T (supposing top is closed and bottom open), this is how it impact a sort of turbulence, where the airflow can fill the T, more or less.

As the open T side is rigidly oriented downward, the influence of the control surface could be limited, except if proper dimensioning of the whole system is adequate.

There is a lot of MAV example where a ducted fan/shroud propeller features vectoring vanes, on 2 axis, and this is a proven design.

As far the Huge Quadrotor is concerned, I understand that the servo at each fan is to counter the rotation generated by 4 CW fans.

After this "neutralization", I understand the attitude stabilization and governing is the same as used in our quad kopter.

A last remark is to notice the huge powerplant needed (LiPo characteristics) to get enough thrust from these ducted fan, based on high speed airflow, where tubing the airflow is just a first step to take advantage of aerodynamics. This is high voltage, high amps project not guaranteeing a manageable and satisfactory thrust to weight ratio.

My ongoing Propeller Shrouded Project (already 2 shrouds builds for test bench experiment is aimed at maximizing the propeller/multiblade custom rotor thrust by aerodynamics to get more thrust, or to reduce the needed power.

I have no particular belief, I just build custom shroud, stator, rotor based on different studies, and I just measure the outcome by experiment, to conclude if it is worthing shrouding, or not, applied to RC scale dimensions (Reynolds number impact).

 

My upcoming tri-shrouded, and quad-shrouded is perhaps at the opposite of this huge thing, consideirng the aim of reducing the powerplant.

 

Comment by Chris on July 20, 2011 at 5:55am

old shit with bad efficencty and much noise, bad control stability.

impellers are not a good choice for a hover platform

the Levitake.de Copter is more then 3years old

here has some one tried to make some tests with the chassis from levitake, but its not good

http://forum.mikrokopter.de/topic-21754.html

Comment by Coptaire on July 20, 2011 at 9:47am

@Chris

the Levitake.de Copter ???

But, but, it is not my impeller based UFO !

Please visit my Propeller Shroud Project, you will see my homemade shroud, not exactly the same thing!

Soon, you will be able to criticize my tri-shroud/quad-shroud.

Comment by bGatti on July 20, 2011 at 9:54am

Vectored Thrust!

It should be pointed out that this design includes a servo at each fan.
With advanced control algs, this could be quite agile and stable (turning a fan can provide Immediate gyroscopic-control ; followed by vectored thrust ; followed by differential thrust.)

Have fun with that.

Moderator Comment by Roberto Navoni on July 20, 2011 at 12:38pm

An other solution is to use 1 motor and variable pitch propeller

http://www.virtualrobotix.com/video/hg3-willy

... we yet fly last year in that configuration .... this year instead i develop a lot of heavy lift as

VR Dragon

http://www.virtualrobotix.com/profiles/blogs/foxteam-support-and-im...

best

Roberto

Moderator Comment by Roberto Navoni on July 20, 2011 at 12:48pm

Another Example of Heavy lift developed using mp32 :

http://www.youtube.com/rnavoni#p/u/27/cXRwh7zsD8s

 

Comment by Cliff-E on July 20, 2011 at 6:37pm

That would never fly, but the design... it all depends.

I've built a 36" tricopter using 65mm ducted fans, was able to lift and hover at 4ft, BUT no yaw stability and precision yaw control sent the thing spinning. The control laws are somewhat different from what I found (can't say due to job). And having servo-actuated vectoring is in the end a bad idea--too much weight and complexity for the thrust EDFs put out.

I do have a 1260APM laying around and 4 55mm ducted fans... nice recipe for another experiment here. :)

Moderator Comment by Roberto Navoni on July 21, 2011 at 5:44am

I CW for stbilize that kind of Quad you need to put flap above the ducted fans so you can govern the yaw. I doing a lot of test on a special huge quad and that is better solution

 

Developer Comment by John Arne Birkeland on July 21, 2011 at 6:00pm

Since the topic is big, here is a full size octo.

http://www.youtube.com/watch?v=_3yjpX54s_U

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