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Dan Thomas

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Why does nobody just stick two large diameter co-axial counter-rotating rotors on top and steer the thing hang-glider style by mounting the assembly on a gimbal?
I used to have a link to a video of a Russian effort similar to that. Can't find it now. The machine didn't work. Any crosswind just makes the thing uncontrollable, which means that as soon as you start moving in any direction it goes crazy. The rotors start generating asymmetric lift due to the crossflow affecting the advancing and retreating blades.

There were a lot of attempts at vertical flight in the early days of aviation. It wasn't until guys like Igor Sikorsky developed the articulated rotors, with lead/lag and flapping functions, that such machines became controllable. They had to learn it the hard way so we don't have to. One has to study helicopter theory to see why things are the way they are.
 

Sockmonkey

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I used to have a link to a video of a Russian effort similar to that. Can't find it now. The machine didn't work. Any crosswind just makes the thing uncontrollable, which means that as soon as you start moving in any direction it goes crazy. The rotors start generating asymmetric lift due to the crossflow affecting the advancing and retreating blades.

There were a lot of attempts at vertical flight in the early days of aviation. It wasn't until guys like Igor Sikorsky developed the articulated rotors, with lead/lag and flapping functions, that such machines became controllable. They had to learn it the hard way so we don't have to. One has to study helicopter theory to see why things are the way they are.
Was the one you're talking about co-axial or single rotor?
 

Aesquire

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I suspect the Electric Mosquito designer didn't want the power drag from the tail rotor drive. ( that the gasoline version uses ) Looks weird but clever, each motor/prop can run at max efficiency. And have zero draw on power when off.

As to coaxial with simple props & not articulated rotors? Doing yaw with differential power requires more throttle or you sink. Stability issues in forward or any other direction flight. Better with a Hiller flying platform.
 

John.Roo

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Letohrad / Czech Republic
I have to loose some weight - I beleive it could be a goo fun with this product :D

PD-ANY is a new concept drone, “Don’t use a drone to carry your payload, turn your payload into a drone”. This unique and easily adaptable platform concept can be attached to virtually any item. It allows you to transport even heavy packages via their four or six adaptable motor arms.
PRODRONE’s goal is for the PD-ANY to make virtually any item fly the same as a conventional UAV through optimizing the best height and position of propellers. Further development, PD-ANY may have a counter-rotating propellers, wireless interaction between motors, and automatic calibration.


1 unit basic parameters:
- payload 15 kg
- weight 4 kg
- flight duration 10 min
;)
 

Dan Thomas

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Still can't find that super-basic fixed-pitch rotor helicopter that didn't work. Here's another one, though:

An engine failure at altitude would probably be fatal. There also seems to be no yaw control.

Now, contrast that with the success and controllability of a fully-articulated rotor helicopter:
 

Sockmonkey

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Still can't find that super-basic fixed-pitch rotor helicopter that didn't work. Here's another one, though:

An engine failure at altitude would probably be fatal. There also seems to be no yaw control.

Now, contrast that with the success and controllability of a fully-articulated rotor helicopter:
That first one wasn't bad control-wise, as out of control in a chopper generally equates to a horrible crash.
But yeah, you want to add some articulation so the blades can lead, lag, and flap.
A tail fin the that tilts side-to side in the rotor wash would give yaw control.
 

Aesquire

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Simply, the complexity and efficiency tradeoffs of having various forms of hybrid drives vs. Old boring gas guzzling engines alone, pretty much demand compromise.

If you replace the gas guzzling engine with a gas guzzling engine, plus generator, plus motor, plus batteries, plus control electronics, it's an over all negative. You need a lighter, more fuel efficient engine with only a small reduction in power to get an improvement of range per unit fuel used.

that's relatively easier in a car in one sense since cars operate at low power settings at cruise. But ironically also easier in a different way in a plane that operates at steady high power output, at cruise.

There's a lot of potential with small motors & props being uncoupled with the main power plant, hybrid or battery, and we're in early days yet.
 

Dan Thomas

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Check out the Archer Aviation Investor Presentation Feb 10th 2021 (PDF Download).
50 pages of really interesting projections.
Some serious money backing eAviation here:

Yup. More vaporware. I'll be waiting to see it fly and carry those four people at 150 MPH for a whole 60 miles. That's less than a half-hour of flight.
 

Dan Thomas

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Archer Aviation "e-Plane" gets a $1bn order from United Airlines........that's serious money!
(Archer could remove 2 seats and install a range-extender).
Must be for experimental purposes. No airline is going to buy an airplane that carries only four people for only 60 miles, after which a lengthy recharge is necessary. Or two people with an ICE range extender. Airlines barely make any money as it is, carrying hundreds at a time. Small commuters running over short distances have to charge a lot more per mile to cover the costs.
 
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