flying a correct coordinated turn

[jay43]

Done

 

 

When you apply collective, a series of push pull tubes translate this movement to the main rotor blades through the swash plates. The pressure applied is called “torque”.

 

 

Yes but it doesn't say TORQUE IS MEASURED BY THE SWASH PLATES does it.

 

How does anyone think the movement of the Collective or Cyclic is transferred to the rotors/blades look at a schematic drawing of the controls for the Huey and you will clearly see push and pull rods traveling from the cyclic and collective along with the anti torque pedals that transfer the pilots inputs on the controls to the swash plates to move the rotor/blades/ anti torque rotor moved by anti torque pedals.

 

Its a translation of movement not measurement that my post refers to no where in the post did I say that Torque was measured by the swash plates.

Edited August 3, 2013 by jay43

[Zentaos]

I thought torque was measured by load on the turbine, ie psi in the compressor. Kind of like how piston engine fighters (p51) engine power is measured by manifold psi.

 

Edit: I understood what you were trying to convey. I suggest reading the rotorcraft flying handbook to everyone interested in truly learning the fundamentals behind helicopter flight. Forums are such a touchy place.

 

The action of raising the collective lever, in turn raises the Non-rotating swash plate. Which then raises the rotating swash plate, that increases the pitch of the blades on the main rotor. The increased pitch adds drag to the rotating airfoil, which starts to slow down. However, the rotor rpm is governed, so as the rpm starts to lag the governor opens the throttle, which increases psi on the turbine, that in effect is increasing the amount of "torque" applied to the main output shaft. Gyroscopic precession has nothing to do with the aerodynamics involved in raising the collective. As the pitch is increased "collectively" through the rotors full range of rotation. It is canceled out anyway (except for needing to understand the physics involved) by control mixing. When you pull the cyclic backwards, the non-rotating swash plate tilts to the left, to compensate for gyroscopic precession.

 

You mentioned it here by the way.

US army video link I posted plus Huey manuals and literature I have says it is measured by the swash plates so you are right and all of the official documentation is wrong Hmmmm.

Edited August 4, 2013 by Zentaos

[Wokka]

Ok show me in said post where the mention of torque measured at the swash plates please highlight.

 

And while we are on the subject mister pilot why not explain in your words how to make a co-ordinated turn I don't see you posting up the answer to the OP yet you claim to be a helicopter pilot so how about it please enlighten me with your wisdom.

 

Look harder, I already explained it by correcting just about everything you said about it. And you said that torque is applied via the swashplates.. This has nothing to do with the torque you get from your torque indicator. Nothing. You indirectly implied that torque is measured at the swashplates.

[jay43]

Ok so what i'll do is take the TC 1-211 manual and throw it in the bin cause everything that's written there is obviously wrong and while am at it i'll contact the US army and suggest they to throw it away even though its been the manual that every pilot that has come through helicopter flight school in the army has had to read and all instructors use to asses candidates.

[jay43]

I thought torque was measured by load on the turbine, ie psi in the compressor. Kind of like how piston engine fighters (p51) engine power is measured by manifold psi.

 

Edit: I understood what you were trying to convey. I suggest reading the rotorcraft flying handbook to everyone interested in truly learning the fundamentals behind helicopter flight. Forums are such a touchy place.

 

The action of raising the collective lever, in turn raises the Non-rotating swash plate. Which then raises the rotating swash plate, that increases the pitch of the blades on the main rotor. The increased pitch adds drag to the rotating airfoil, which starts to slow down. However, the rotor rpm is governed, so as the rpm starts to lag the governor opens the throttle, which increases psi on the turbine, that in effect is increasing the amount of "torque" applied to the main output shaft. Gyroscopic precession has nothing to do with the aerodynamics involved in raising the collective. As the pitch is increased "collectively" through the rotors full range of rotation. It is canceled out anyway (except for needing to understand the physics involved) by control mixing. When you pull the cyclic backwards, the non-rotating swash plate tilts to the left, to compensate for gyroscopic precession.

 

You mentioned it here by the way.

 

That's post 36 look at 31 and 32 to acertain the first mention of torque measured at the swashplates was not in my post my post 31 refers to torque applied not measured.

For the record we have pilots in the 1stCavDiv now which have also proved they are pilots and all say that's the way to do it I have followed what they said which is in post 31 and I lose no altitude or speed when flying coordinated turns.

Wokka I invited you to join us I see you haven't yet be nice to get another pilot on board especially one that disagrees with what the other pilots are saying for all I know you could be a chef and a part time pilot show me the proof and then I might listen to you I could say I work for NASA on here doesn't mean I do.

[26-J39]

An outside perspective here.. Chill guys, I can see there's alot of confusion in the way the debate is expressed. Going in circles lol. Regarding the OP's question, I agree with Wokka. I'm no RL pilot but I know how to fly and sorry but he's right. (No swash plate relevance in this post!)

 

No collective or rudder input during a coordinated turn. That is just plain funny..

[epokha]

I'm no expert...

 

But I just learnt the method of only using the rudder for yaw and then pulling back on the cyclic to maintain the attitude/altitude. The bank angle maintains the turn. Like in the training manual that was posted (http://www.tc.gc.ca/eng/civilaviation/publications/tp9982-exercise6-975.htm).

 

I can get it to work perfectly with no speed loss, much easier to maintain then juggling the collective and rudder pedals. Works upto 40-50 degrees after that you get low RPM warning at higher speeds..

Edited August 5, 2013 by epokha

[26-J39]

It's actually pretty simple.. A helicopter (w- tail rotor specificly) always requires constant attention to all 4 control axis. Done.

[Wokka]

lol, true.

[epokha]

You need the extra power when you enter the bank. But once that's set its easier to maintain altitude/attitude with the cyclic then trying to do it with the collective. At least it is with my setup.

[159th_Falcon]

When you apply collective, a series of push pull tubes translate this movement to the main rotor blades through the swash plates. The pressure applied is called “torque”.

 

 

Yes but it doesn't say TORQUE IS MEASURED BY THE SWASH PLATES does it.

Push pull rods transmit PRESSURE (or tension, depending on way of travel and rotorhead construction)

They do not, and can not, apply torque.

 

I thought torque was measured by load on the turbine, ie psi in the compressor. Kind of like how piston engine fighters (p51) engine power is measured by manifold psi.

 

Edit: I understood what you were trying to convey. I suggest reading the rotorcraft flying handbook to everyone interested in truly learning the fundamentals behind helicopter flight. Forums are such a touchy place.

 

The action of raising the collective lever, in turn raises the Non-rotating swash plate. Which then raises the rotating swash plate, that increases the pitch of the blades on the main rotor. The increased pitch adds drag to the rotating airfoil, which starts to slow down. However, the rotor rpm is governed, so as the rpm starts to lag the governor opens the throttle, which increases psi on the turbine, that in effect is increasing the amount of "torque" applied to the main output shaft. Gyroscopic precession has nothing to do with the aerodynamics involved in raising the collective. As the pitch is increased "collectively" through the rotors full range of rotation. It is canceled out anyway (except for needing to understand the physics involved) by control mixing. When you pull the cyclic backwards, the non-rotating swash plate tilts to the left, to compensate for gyroscopic precession.

 

You mentioned it here by the way.

 

Depending on helicopter, you are correct. (torque can also be measured by measuring how many degrees the drive shaft twists along its axis, for example)

 

You make a small mistake at the end though. A swashplate is one unit, build up out of the lower and upper halves.

As it is one part, its not physically possible that the lower section tilts forward while the upper section tilts sideways.

 

The 90 degree offset is usually created by the way the rotor head is constructed and the place where the pitch link attaches to the rotorhead.

(or rotor blade, or pitch change lever etc etc etc)

 

You need the extra power when you enter the bank. But once that's set its easier to maintain altitude/attitude with the cyclic then trying to do it with the collective. At least it is with my setup.

 

exactly!, so if we compare the situation during straight and level flight to the situation in an coordinated turn control inputs that have changed are;

cyclic

pedals

collective

(and throttle as well, could be automatic, or manual though)

 

Just like we said before.

 

Below an picture of a swashplate, incase people here don't know how it looks.

As you can see quite nicely in this picture, its one unit.

(this particular picture shows an model helicopter swashplate but overall construction is the same, just smaller)

Edited August 5, 2013 by sobek

[26-J39]

Nice post Falcon.. :)

 

oh sweet lookin swash plate!! :happy:

[lorenzoj]

Everytime I look at the components on my rc helis, part of me still thinks, "this can't possibly work or stay attached for long if it does". Has to be more then a little magic involved in this technology.

[skouras]

No it doesn't

And as such you should not fly it as an fixed wing.

 

Two totally different things.

 

To turn in a helicopter;

Move cyclic left/right to initiate the turn

Use pedals to prevent side slipping

Move cyclic forward to keep the speed you were flying

Move collective up to compensate for the extra thrust required by the new attitude of the helicopter.

 

Please note that in certain parts of the helicopters performance envelope it may not be possible to keep both speed and altitude while making a given turn.

;)

[sobek]

Enough of the bickering.

 

Keep posts respectful towards other users or prepare to face consequences. That goes for users with AND without seniority.

[JoeDiamond]

In forward flight a helicopter shares a lot of characteristics with a fixed wing.

 

They are similar in that they are both aircraft and they both fly, and that's where the similarity ends.

[sobek]

A friendly reminder, if you don't wish your posts to end up deleted, don't engage in discussion and quote posts that are so far outside the rules that it's a given they are going to be deleted. We can't just leave one side of the discussion, it would break the readability of the thread. That being said, if you want to discuss moderation policy, we kindly ask you to abide by forum rule 1.3 and do so per PM, not publicly.

[VanjaB]

Will anyone post a .trk of a coordinated turn so we can all see what we are talking about?? I for one cant do one without adding a little bit of collective so I would like to see someone do it so we can end this discussion once and for all. Thank you.

[epokha]

Will anyone post a .trk of a coordinated turn so we can all see what we are talking about?? I for one cant do one without adding a little bit of collective so I would like to see someone do it so we can end this discussion once and for all. Thank you.

I'm not saying that you don't need to add collective at the start, its just you shouldn't need to change it once you have the right setting in place, your better off focusing on the attitude with the cyclic to make minor adjustments.

[lorenzoj]

Interesting quote from Chickenhawk,

 

"It wasn't a matter of just putting the collective in one position and leaving it there; constant corrections had to be made."

[julian265]

Normally the main rotor's thrust vector is pointing downward and backward (and a little to one side).

 

Any roll will point the thrust vector off to one side, which will reduce the downward thrust... Unless you pull more collective.

 

Therefore, if you want to maintain your speed AND altitude through a turn, you will need more collective.

 

Why get into semantics when the basics prove a point?

[jay43]

Then perhaps you should come and do a check ride with 1stCavDiv Instructor pilot who has over 2000 hrs in the Huey.

 

As this is how its done by the instructor.

Pull CP to gain 10ft hover check to set Torque PSI usually around 30psi in DCS slicks.

Theres your base level you now only need plus or minus 5 psi for take off and landing.

Flying a closed traffic pattern climb to 10ft hover check psi should be 30 psi now plus 5 on the psi nose down 10 degrees pushing through ETL is nice and smooth like this no sudden jumps no shakes or wobbles.

Maintain nose down 10 degrees climbing to 1000ft level off drop CP by 5 psi and maintain 70knts.

Begin closed traffic pattern and from the instructor don't touch the CP its set make your turn gentle 10 degrees and guess what no loss of altitude and no gain of altitude speed maintained at 70knts.

On final drop CP by 5 psi for a nice even steady decent to the ground flare and land.

[JoeDiamond]

If you are not adding power in a turn you are trading airspeed for altitude. It does not matter if you are flying an airplane or helicopter. It's physics plain and simple. When you bank an aircraft you are tilting the lift vector , decreasing the vertical component and increasing the horizontal component. If you don't increase power to replace the lost vertical component of lift you will sink if you maintain airspeed, you will slow down if you maintain altitude. To maintain both altitude and airspeed you have to add power, which in a helicopter is done by adding collective.

 

And before you ask, yes, I have 27 years of real world experience to back this up.

[lorenzoj]

I have to spend a little more time playing with it, but the procedure outlined above by jay43 seems to kinda work. My execution was a bit sloppy the first go but did look promising actually.

 

And remember that it calls for "gentle" turns of 10 degrees.

Edited August 12, 2013 by lorenzoj

[scrtagnt69]

In RL my hand rarely leaves the collective and when it does it is for 3-5 secs max.