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Help and Support Forums => Help and Training => Topic started by: 28sweep on May 01, 2002, 07:29:31 AM

Title: What Keep's the Dot Centered?
Post by: 28sweep on May 01, 2002, 07:29:31 AM
1) Until today when I flew I did not have rudder control-not even a twiste on the joystick.  So my question is what keeps the ball centered and my turns perfectly coordinated?  Is it like "auto-trim" or something?  Can u turn it on and off?

2) Now I have USB Ch Pro Pedals.  I installed the software and and went to set-up/joystick I think-the screen where u have x, y ,z and some coordinates?  So I push down the pedals and the coordinates change and look ok and when I fly it's all screwed up.  I guess I am looking for some help in the set-up of the pedals in AH.  I'm at work and don't exactly rember where I screwed-up this morning?
Title: What Keep's the Dot Centered?
Post by: CavemanJ on May 01, 2002, 07:57:48 AM
Sounds like you've got combat trim turned on.  Combat trim will keep the aircraft close to proper trim for full power at a given a speed.


Can't help ya with the pedals, sorry.  Never messed CH USB pedals before.
Title: What Keep's the Dot Centered?
Post by: 28sweep on May 01, 2002, 08:12:46 AM
Trim does NOT KEEP THE BALL CENTERED!!  NOT IN A REAL AIRPLANE ANYWAY!  RUDDER DOES!
Title: What Keep's the Dot Centered?
Post by: Eagler on May 01, 2002, 08:35:21 AM
hands of, rudder trim should put the ball in the center

turning, change in speed, you'll use the peds to center the ball - slight input only needed

Don't know about combat trim, don't use it
Title: What Keep's the Dot Centered?
Post by: 28sweep on May 01, 2002, 09:14:27 AM
So when u turn rudder input is required to keep the ball centered.  I have no rudder control at all.....or I didn't before- and the ball always stayed centered.......trim has nothing to do with it....ok I guess there is rudder trim but that won't keep the ball centered when u turn.
Title: What Keep's the Dot Centered?
Post by: Eagler on May 01, 2002, 09:53:06 AM
rudder trim does have something to do with it unless you always want to correct using ur rudder input ->peds, twisty stick or keyboard
"ok I guess there is rudder trim but that won't keep the ball centered when u turn."
Correct thats where ur rudder input keeps it close
Title: What Keep's the Dot Centered?
Post by: 28sweep on May 01, 2002, 12:24:58 PM
but HOW DOES THE BALL STAY CENTERED WHEN U HAVE NO RUDDER CONTROL???
Title: What Keep's the Dot Centered?
Post by: Eagler on May 01, 2002, 12:35:30 PM
Quote
Originally posted by 28sweep
but HOW DOES THE BALL STAY CENTERED WHEN U HAVE NO RUDDER CONTROL???


I don't think it will

Don't know the keys but you can control the rudder from the keyboard but I suggest a twisty stick or usb peds ... gl
Title: What Keep's the Dot Centered?
Post by: SKurj on May 01, 2002, 01:02:58 PM
i can turn all day without getting the ball centered dunno what yer problem is +)  I do use CT

I also use CH Pro Pedals USB
Z is rudder axis
x and y are left and right toe brakes


SKurj
Title: What Keep's the Dot Centered?
Post by: HFMudd on May 01, 2002, 01:34:44 PM
The ball and no trim depends on the plane and the speed.  I've assumed that that auto trim is doing something since the ball stays centered well in some planes within a given speed band.

For example: The Bf-109G6 requires a good deal of rudder at low speed to keep the ball centered.  Once above 200 or there abouts I can take my feet off the pedals (CH USB),turn and the ball stays well centered until enough speed is burned off.  Once down below 200 the ball drifts again and rudder input is needed.

In short, while I would a agree with the statement that "Trim does not keep the ball in the center, rudder does!"  I don't think that is the same as "The AH algorythm that manages the trim of the rudder will not adjust the rudder within in a given speed band to keep the ball in the center."

Perhaps HiTech will chime in here?
Title: What Keep's the Dot Centered?
Post by: 28sweep on May 01, 2002, 03:04:14 PM
So here I go again....when I took real flying lessons (I logged 10 hours in a 172) I rember that EVERY turn required BOTH stick (wheel) and rudder.  The stick (wheel) rolled the airplane and the rudder coordinated the turn and kept the ball centered (yes u can also pull back on the stick and use elevator in a turn).  Like my first 3 hrs. the instructor told me not to bother with the pedals and use the wheel and I rember the THE BALL WAS NEVER CENTERED during this time (almost never).  Now I fly much more complex aircraft (in the Sim I mean) and I have no rudder control at all and I am doing extreem turns and I look up and the ball is always centered.........how is that possible?  The bigger and more complex aircraft require more careful turn coordination and a Lancaster is a lot more complex than a Cenesna 172 !!!!!!! I know MS Flight Sim. has an auto coordination feature.  Is that what is going on here??????????
Title: What Keep's the Dot Centered?
Post by: Eagler on May 01, 2002, 03:41:07 PM
try hitting ctrl X while in AH and see if your ball moves

I think combat trim is control X. Also make sure it is disabled in your options before you take off
Title: What Keep's the Dot Centered?
Post by: HFMudd on May 01, 2002, 03:49:53 PM
To paraphrase The Matrix, "So you think that's real air you're flying in?" and "Remember, there are no trim tabs."

I really, honest to gosh, don't know how HTC does their Combat Trim software wise so I'm *really* going out on a limb here but I would venture to guess that the actual aerodynamics of the way a trim tab works is not really modeled.  Instead some lookup goes on in the background that says, "For speed X at bank Y deflect the rudder Z degrees."

How 'bout this.  Instead of pretending you are flying the Cessna 152 you probably took your lessons in, how about pretending you are flying an Aircoup with linked ailerons and rudders.
Title: What Keep's the Dot Centered?
Post by: HFMudd on May 01, 2002, 03:54:44 PM
I have a question for the RL pilots out there...

I have never flown anything other than a Taylorcraft and that was some time ago in the glory days when I lived at home and my Dad owned a plane.  (And three hours in a 777 full motion simulator but that hardly counts.)  In higher performance aircraft (200+ mph) how well does the ball stay centered during a turn without rudder input?
Title: What Keep's the Dot Centered?
Post by: DAVENRINO on May 01, 2002, 05:06:42 PM
HFMudd,
-----------------------------------------------------------------------------------
To paraphrase The Matrix, "So you think that's real air you're flying in?" and "Remember, there are no trim tabs."

I really, honest to gosh, don't know how HTC does their Combat Trim software wise so I'm *really* going out on a limb here but I would venture to guess that the actual aerodynamics of the way a trim tab works is not really modeled. Instead some lookup goes on in the background that says, "For speed X at bank Y deflect the rudder Z degrees."
-----------------------------------------------------------------------------------
I don't know anything bout sim programming, but I would guess you have made the correct assumption.  I do know a lot bout RL planes.  Jet transport and fighter ac handle turn coordination through yaw dampers and computers.  You never touch the rudders in a jet tranport except for takeoff, landing, and engine out operations. Some modern jet ac,such as the 777 even handle most of the engine out ops.
DJ229
Title: What Keep's the Dot Centered?
Post by: DAVENRINO on May 01, 2002, 05:34:28 PM
...cont

HFMudd,
The yaw damper computers also keep the ac from tail-wagging in turbulence.  The yaw dampers are so important that a DC10 ,for example, must have 2 of the 4 installed systems operational before it can take off.

WW2 airplanes didn't have yaw dampers but maybe HT modeled them to fly as if they did.

DJ229
Title: What Keep's the Dot Centered?
Post by: DAVENRINO on May 01, 2002, 06:18:08 PM
...cont

The rudder input to coordinate the turn is mainly necessary to counter the drag resulting from the lift created by the aileron diplaced downward.  Any time you create lift, drag is also created.  An aileron farther out on the wing also creates more yaw such as on aircraft with unusually long wings such as gliders.  The faster you go, less aileron is required for the same roll rate resulting in less yaw and less rudder required.  A DC10 locks out the outboard ailerons when the leading edge devices retract somwhere between 250-270 knots. Jet transport ac also use spoilers in combination with ailerons to reduce drag and resulting yaw. Hope this explaination more than it confuses anyone.
DJ229
Title: Re: What Keep's the Dot Centered?
Post by: Puck on May 01, 2002, 06:43:29 PM
Quote
Originally posted by 28sweep
2) Now I have USB Ch Pro Pedals.  I installed the software and and went to set-up/joystick I think-the screen where u have x, y ,z and some coordinates?  So I push down the pedals and the coordinates change and look ok and when I fly it's all screwed up.  I guess I am looking for some help in the set-up of the pedals in AH.  I'm at work and don't exactly rember where I screwed-up this morning?


X Axis: Left brake
Y Axis: Right brake
Z Axis: Rudder

I don't use the CHController software for AH, I just set everything in the Stick Setup dialog.  It's a pain sometimes, because it seems if I ever unplug anything I have to re-assign all the axis and buttons, but it's bulletproof otherwise.
Title: What Keep's the Dot Centered?
Post by: Mino on May 02, 2002, 06:30:25 AM
Keep one this in mind.  A Cessna 172 or a Taylorcraft fly at low speed.  Lets say 150knots or less.  At those speeds the rudder does have a much greater effect.

But....

At higher speeds the rudder effect becomes much less.  If your cruising along at 350knots, it does not have much effect at all.

The rudder is the control that you use to keep the ball centered.

Now to keep the ball centered, you use your rudder the same side the ball moved  IE: "Step on the ball".

This works in AH.  At low speeds you have a great deal of effect upon yaw using the rudder, at higher speeds much less.

Personally, I don't pay much attention to it, except on take off or high altitude turns.