Rockets at tips of rotor blade

[simonrockman]

http://www.wired.com/autopia/2010/08/one-man-rocke...

[Amused2death]

I like that

I wonder if this aircraft would auto like a normal heli?

[Flintstone]

I think it would, same laws of physics apply.

[anonymous-user]

Check out fairey rotodyne. Bloody noisy, I mean painfully Noisy. No need for a tail rotor though.

[dr_gn]

Apparently the Rotodyne main rotor was unpowered during forward flight.

Not figured out how you get away with no tail rotor on tip powered blades...surely there is some friction in the rotor head bearings, which would tend to spin the fuselage in the same direction as the blades?

[perdu]

The Rotodyne had a pair of sod off big turboprops giving it the forward thrust so I suspect the induced forces from those on Fairey's big square box would tend to overcome any turn tendency

And she had a pair of tailfins too for directional stability


Probably over configured according to modern designs, but after all was said and done the intense howling from the tip jets made them un-user friendly

Shame, when I was a lad I'd have given an arm (either) for a flight in one, I loved the thing

[dr_gn]

perdu said:

The Rotodyne had a pair of sod off big turboprops giving it the forward thrust so I suspect the induced forces from those on Fairey's big square box would tend to overcome any turn tendency

And she had a pair of tailfins too for directional stability


Probably over configured according to modern designs, but after all was said and done the intense howling from the tip jets made them un-user friendly

Shame, when I was a lad I'd have given an arm (either) for a flight in one, I loved the thing

Yep, probably an inertia thing stopping it rotating in vertical flight, with the other factors you mention taking over in forward flight.

[Eric Mc]

It was basically a "sod-off autogyro".

[davepoth]

dr_gn said:

perdu said:

The Rotodyne had a pair of sod off big turboprops giving it the forward thrust so I suspect the induced forces from those on Fairey's big square box would tend to overcome any turn tendency

And she had a pair of tailfins too for directional stability


Probably over configured according to modern designs, but after all was said and done the intense howling from the tip jets made them un-user friendly

Shame, when I was a lad I'd have given an arm (either) for a flight in one, I loved the thing

Yep, probably an inertia thing stopping it rotating in vertical flight, with the other factors you mention taking over in forward flight.

It's a torque thingy. As the rotor on a normal helicopter is acted on by the torque from the fuselage, the fuselage is acted upon by the rotor's torque because they are connected by a shaft. There isn't a shaft in a tip-jet design, so the torque isn't transferred.

[Zad]

I wrote various bits n bobs about the Rotodyne here, but it is probably better if you just read the original Flight article here: http://www.flightglobal.com/pdfarchive/view/1957/1...

Edited by Zad on Friday 20th August 02:12

[dr_gn]

davepoth said:

dr_gn said:

perdu said:

The Rotodyne had a pair of sod off big turboprops giving it the forward thrust so I suspect the induced forces from those on Fairey's big square box would tend to overcome any turn tendency

And she had a pair of tailfins too for directional stability


Probably over configured according to modern designs, but after all was said and done the intense howling from the tip jets made them un-user friendly

Shame, when I was a lad I'd have given an arm (either) for a flight in one, I loved the thing

Yep, probably an inertia thing stopping it rotating in vertical flight, with the other factors you mention taking over in forward flight.

It's a torque thingy. As the rotor on a normal helicopter is acted on by the torque from the fuselage, the fuselage is acted upon by the rotor's torque because they are connected by a shaft. There isn't a shaft in a tip-jet design, so the torque isn't transferred.

I understand that, but my initial assumption was that if the rotor is turning, and is connected to the fuselage via bearings, then the bearings must have some friction and resistance which would tend to turn the fuselage. Take it to the extreme and imagine the bearings siezed, and the whole lot would spin around.

Of course if the rotors are small and light relatave to the fuselage, then inertia would presumably play the significant role.

[anonymous-user]

dr_gn said:

davepoth said:

dr_gn said:

perdu said:

The Rotodyne had a pair of sod off big turboprops giving it the forward thrust so I suspect the induced forces from those on Fairey's big square box would tend to overcome any turn tendency

And she had a pair of tailfins too for directional stability


Probably over configured according to modern designs, but after all was said and done the intense howling from the tip jets made them un-user friendly

Shame, when I was a lad I'd have given an arm (either) for a flight in one, I loved the thing

Yep, probably an inertia thing stopping it rotating in vertical flight, with the other factors you mention taking over in forward flight.

It's a torque thingy. As the rotor on a normal helicopter is acted on by the torque from the fuselage, the fuselage is acted upon by the rotor's torque because they are connected by a shaft. There isn't a shaft in a tip-jet design, so the torque isn't transferred.

I understand that, but my initial assumption was that if the rotor is turning, and is connected to the fuselage via bearings, then the bearings must have some friction and resistance which would tend to turn the fuselage. Take it to the extreme and imagine the bearings siezed, and the whole lot would spin around.

Of course if the rotors are small and light relatave to the fuselage, then inertia would presumably play the significant role.

Yeah there is a friction force but it will be negligible when compared to the overall forces and inertias.

[Zad]

Yaw control at low speeds is performed by varying the thrust from each prop.

[Eric Mc]

Proof of concept Gyrodyne



Rotodyne