Replies to This Discussion

Permalink Reply by bGatti on October 16, 2010 at 6:36pm

One large prop is more efficient than n smaller props; The advantages of a quad are the simplicity and efficiency of direct drive motors juxtaposed against the complexity of a cyclical etc. These advantages are presumably lost as the cost and size of the vehicle goes up. Your fixed pitch quad rotor of any size will crash, and with it whatever you carry; an adj. pitch rotor on the other hand allows for a dead stick landing, so your odds go up.

I suspect someone will build an n rotor with sufficient props to lift a human (~50-70)? and such may be safely redundant, but arguably a heli would be more effecient. (however, might it be oddly quiet - having a high frequency and lacking the main source of whoop-whoop (the tail crossing)?

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Permalink Reply by Sebastian Gralla on October 17, 2010 at 1:52am

there is / was a Quad that can lift a human:

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Permalink Reply by Chris McNair on October 17, 2010 at 7:00am

Would not want one of those front blades to come off and hit you!

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Permalink Reply by John Ryan on October 18, 2010 at 2:12am

yes there it is. That could use a face lift, something colorful like a parrot might be nice, and rubber guards surrounding the blades for a bit of safety perhaps. It might look more balanced if the pilot were in the middle and protected by a glass canopy. The booms could be further apart, and that fat thing sticking out the end can go too.

I wish I had too much time, up-sizing the Arduquad would make a fun challenge even if it didn't work.

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Permalink Reply by Arthur P. Meiners on December 2, 2010 at 4:53pm

There is a company in the US working on a very large quad design which could be used e.g. to get people off of very high skyscrapers in case of fire. It looks somthing like an oil rig with four large enclosed rotors and a ramp with walking bridge which will extend a bit from the front to allow people to step onto the top of the thing. Hasn't flown yet, but I think they have some working scale prototypes which are still quite large and may have flown by now. When moving from an old computer I lost the link, but you should be able to find it in Google when searching for e.g. quadrotor rescue missions.

And the US military / aviation industry seem to be working on a replacement for the Hercules aircraft which would be a sort of double-winged Osprey with four tilt-rotors and would be able to lift a tank and crew VTOL. http://en.wikipedia.org/wiki/Bell_Boeing_Quad_TiltRotor

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Permalink Reply by flynx on June 10, 2011 at 1:52pm

I was doing some market research on large electric power systems and I found this brushless motor:

 

http://www.icare-rc.com/plettenberg_predator.htm

 

which can generate 65 lbs of thrust swinging a 30x10 prop.  4 of those would make 260 lbs lift.  The motor itself weighs under 4 lbs so if you could keep the weight of the batteries and vehicle under about 100 lbs then you could lift a light person.

 

Ballpark between $16,000 and $18,000.

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Permalink Reply by Pbreed on June 10, 2011 at 3:33pm

Try this:

http://www.geekosystem.com/guy-builds-working-hoverbike/

 

IMHO Should be 4 counter rotating blades with hybrid electric drive.

 

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