helicopter thrust

[helicopter2009]

Does anyone know how thrust of a typical helicopter change in forward flight along azimuth angle? What about other manoeuvers?

[Non-PC Plod]

It is not clear what you are trying to ask. You may need to get help with a technical translation into English of what you want.

[helicopter2009]

I don't know how the thrust changes with the azimuth angle ( thrust of a helicopter as a function of azimuth angle). Is there anyone who can helps?
thanks Agaricus bisporu (http://www.pprune.org/members/11154-agaricus-bisporus)
Agaricus bisporu for his/her hint.

[Miles Gustaph]

...I trust that the rotor head wont fly off when a helicopter moves into translational flight....

...you could have a legal trust as part of a leasing deal...

...and your trust in the pilot will change if he flys around so as to make you sick...

[ShyTorque]

My english probably not good enough but I trust helicopter irrespective of azimuth angle.

[Miles Gustaph]

But is trust proportional or inversely proportional to the azimuth angle?

[ShyTorque]

I use the formula:

Torque = once bitten, twice Shy.

[zhishengji751]

This might help.. (Aerodynamics of flight)

Basic Helicopter Handbook (http://www.geocities.com/flyingmouse1/Chapter_2.html)

[Agaricus bisporus]

You will find chapter and verse in books or on the internet. The subject of helicopter aerodynamics is far far too large to be answered here, but as I recall it all condenses down somehow to "Big Green Arrows" and "Little Green Arrows"

"Thrust" is a word little used in Helicopter-speak, except in complex descriptions of force-vectors affecting rotor systems and aerodynamics. In such cases it is always attached to other term/s to define it, as in "Forward" thrust "Vector". It's use alone, as you did, is almost meaningless because it is not defined.

Note it's spelling, thrust with an "h", the word you used is totally different, which explains a lot of the posts above.

Happy reading!

ps. Best to get your own knowledge of terminology and language correct before you grizzle at people who do know it correctly...?

[topendtorque]

and I can say with some feeling,
trust in the helicopter game is neither yer arz nor yer muth.

an' trust me,

how long before the colour blind gentlemen of our constituency get the screamin' s***s with the blas*** colour coded entree server.

fair dinkum SP that has got to take the cake as pprune's worsarz nightmare.

[helicopter2009]

I have seen basic helicopter handbook. But it couldn't help. thanks anyway.

[[email protected]]

Go on then - I'll bite:ok:

Helicopter 2009 - in zero wind (or zero forward speed if you prefer) at a given pitch angle, a rotor blade will produce the same lift (thrust) throughout its 360 degrees of travel.

If you add wind from the front (or forward speed), the blade moving forward from a position over the tail (the advancing blade) will experience increasing airspeed until it is at 90 degrees to the fuselage and then the airspeed will reduce until it get to the nose where it will have the same airspeed as it did over the tail. From nose to tail, the blade (now the retreating blade) will experience reducing airspeed as the wind is coming from behind it - the minimum airspeed position will be at 90 degrees to the fuselage opposite to the maximum airspeed position, then the airspeed will gradually increase again until the blade is over the tail once more having completed a full 360 degrees.

If you increase the airspeed over an aerofoil at a given pitch setting, you will produce more lift (thrust) and if you reduce airspeed you produce less lift.

That hopefully answers your question that lift (thrust) does change in azimuth on a helicopter, but only when there is a difference of airspeed around that azimuth due to wind or forward speed.

[WASALOADIE]

The Chinook has an Aft Propulsion Unit (APU), a small jet engine in the aft pylon to give forward thrust thereby allowing the rotors to purely generate lift. The crewmen move from side to side and the CofG change makes the a/c move left or right.

[ShyTorque]

Yes, we've all seen the size of those Chinook crewmen.

[zhishengji751]

The Chinook has an Aft Propulsion Unit (APU), a small jet engine in the aft pylon to give forward thrust thereby allowing the rotors to purely generate lift. The crewmen move from side to side and the CofG change makes the a/c move left or right.

How does it turn/change azimuth? :)

[WASALOADIE]

The front crewman goes right and the back crewman goes left or vice versa, this is DCP (Differential Crewman Position). Pitch is achieved by the crewmen moving forward or aft which is known as Longitudinal Crewman Trim (LCT). Pitch can also be varied by increasing or reducing the power on No1 engine which in turn increases or reduces the speed of the rear rotor thereby increasing or decreasing the lift. Or alternatively by increasing or reducing the power on the No2 engine which gives the same effect on the forward rotor head. If you increase the power on both engines then the lift is increased on both rotor heads and the a/c will lift vertically.

[ShyTorque]

If you increase the power on both engines then the lift is increased on both heads

Both crewmen's heads? :E