How do you steer a single rotor helicopter

[Lan Ding Gere]

Just a question guys,

Helicopters that have the main rotor and no rotor on the tail. how is this steered.

Are there jet nozzles or something that are used like thrust vectoring that turn the copter from left to right when it is hovering for example ?

[topcat450]

Have a peek at this (http://www.scienceweb.org/movies/speed.html)

or, for more info, try looking here (http://www.mdhelicopters.com/AboutNOTAR/About_Notar.htm)

[The Invisible Cat]

What the hell is that thread doing in JB ? :* :* :confused:

There are places like Tech Log or Rotorheads for seri0us stuff like this.

MOD ERATORS
puh-lease do something !

[Lan Ding Gere]

Thanks Topcat

:)

Sorry guy's

i hadn't realised I put this in the wrong section.

I have a habit of looking in the Jetblast page first.

Sorreeeee....:( ;) ;)

[Ausatco]

A bit OTT, TIC, don't you think?

AA

[a is dum]

NOT AT ALL
TIC is correct to draw attention to this serious mishap.

We have to keep a certain standard at Jetblast, even during the fairly loose moderating level we experience these days.



:rolleyes:

[The Invisible Cat]

Lan Ding Gere

Nurries, mate.
One was not aiming at you, one is fully aware that this kind of things can happen, but as a is dum pointed out, us JetBlasters do adhere strongly to our moral values. :rolleyes:

Unknown Moderator, whoever you may be, you shall be thanked many times for moving this thread where it belongs.
May you and your offspring (when and where applicable) be blessed until the seventh generation. :ok:

[SilsoeSid]

LDG,

If you visit here, you can see the 'drum' in action.

902 from behind.....fnaaah!! (http://www.geocities.com/pprunessilsoesid/)

SS

[Hilico]

Lan

Doesn't sound as though you know much about helicopters. Well, neither do I, but one thing I do know is that the rotor on the back isn't used for steering. (It's used for pointing the body of the helicopter, which isn't the same thing. Helicopters bank in the direction they want to turn in.)

The ones that don't have a rotor on the back come in two flavours. One has a hole in the tail with a 13-blade fan in it, and that's called a fenestron. Helicopters like this are made in Europe. You probably don't mean this one, though.

The other system is called NOTAR (NO TAil Rotor). The tail, which is a lot thicker than usual, has air blown through it by a fan just behind the main rotor (you can't see it unless the machine is stopped and you have a stepladder). Some of this air comes out of a slot that runs the length of the tail. This makes the downdraught from the main rotor curve round the tail making it act like a wing and pull in one direction, against the twist from the rotor. For fine adjustment, the rest of the air comes out of a thrust-vectoring nozzle (just as you thought) right on the end of the tail. That system comes from the USA.

[SilsoeSid]

Hilico
....one thing I do know is that the rotor on the back isn't used for steering. (It's used for pointing the body of the helicopter, which isn't the same thing. Helicopters bank in the direction they want to turn in.)
Much like the wheels of a car aren't used for steering, but for pointing the body of said car. :confused:
Cars roll in the opposite direction that they want to turn. :oh:

Which design of those 2 (fenestron or NOTAR) does this fall into?

http://www.pilotlist.org/helico/rotodyne.jpg

Hilico, a technique used in the military for v.low flying to prevent disc contacting ground is to 'drive' the aircraft around.
Used in a quick hover taxi situation such as recce mission movement around obs position or anti tank into/out of fire position. Typically when there is little cover, ie Canadian Plains.

Basically, the disc vector is maintained in the 12 o'clock and all turns are made with pedal. This prevents the disc being tilted enough left or right during a turn to contact the ground. Apart from any rising ground, the lowest point of the disc is always readily in view, straight ahead.

After all, we're only drivers/airframe! :ok:

[Straight Up Again]

SilsoeSid - The Rotodyne was a tip jet aircraft, and thus did not need any anti-torque device to stop the airframe spinning.

I am curious as to it's ability to do spot turns? Does anyone know if it could, or did it just lift vertically before transitioning to forward flight, where fixed wing type control was available?

(I saw one of the tip jets at the Weston-Super-Mare museum, they were huge)

[SilsoeSid]

The Helicopter Museum at W-s-M, is quite a place. I went a while back and the Rotodyne jets were in a box ready to be placed on display. like you say Straight Up, huge.
(Anti-torque not mentioned in original question, steering is.)

I think you'll find that in the hover and in forward flight, yaw was controlled by differential propeller pitch. Once in forward flight the aerodynamic surfaces would be come more effective.

Strangely enough, Westland took over Fairey and despite commercial interest, shortly afterwards the project was cancelled.

[Hilico]

SilsoeSid, I did say I didn't know much! I didn't get taught that way of steering as a civvy, and I suspect that very few outside the military do - after all, most of them aren't required to fly below what I was taught was hover height.

The difference between a car and a helicopter is that the car is always touching the ground, so whichever way the wheels point, the car goes. The NOTAR can fly sideways and backwards at 40 or 50mph, so whichever way it's pointing isn't necessarily the way it goes.

[SilsoeSid]

Hilico, just passing on some information, didn't mean to upset you, sorry. :(

Surely you must have been taught/shown/experienced hover taxying.
So, how do you go round the corners? :confused:

[Hilico]

SilsoeSid, no offence taken. But have you seen the speed I hover taxi at? Even if it's a small bank, it's a bank.

More seriously, at my experience level, I don't turn many corners while hover taxiing - stop, pedal turn to new direction and carry on, maybe.

AND ONE MORE THING (this added 8pm local, 2nd July 04) - I've just had a look through Bailey Vol 1 and it doesn't actually mention this specific topic! Hover-taxiing isn't covered in the air exercises, and the helicopter handling section only mentions hover-taxiing in a straight line, and spot turns - nothing about 'when cornering at 10mph use pedals only and maintain level with cyclic' or (as I would think) 'use very gentle bank angles and maintain direction with pedals'.