Author Topic: Realistic flight model?  (Read 1143 times)

Offline scottydawg

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Realistic flight model?
« on: April 24, 2006, 11:54:07 AM »
I'm curious about the flight model, in particular the 'elevator bounce' and 'rudder wibble' (my words) I get when I fly.

For example if I move the elevators and release to center, I get what I can only describe as a rubber-band like bounce, as if the plane was held in place by rubber bands.  is this realistic?

Give it a try in the MA, line your sight up with something and pull rudder and release to center. It's bizarre.  Do planes really do that?

:D

Offline Roscoroo

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Realistic flight model?
« Reply #1 on: April 24, 2006, 01:28:00 PM »
hit ctrl x   (turns off auto trim)  then see what they do .
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Offline Max

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Re: Realistic flight model?
« Reply #2 on: April 24, 2006, 01:37:52 PM »
Quote
Originally posted by scottydawg
I'm curious about the flight model, in particular the 'elevator bounce' and 'rudder wibble' (my words) I get when I fly.

For example if I move the elevators and release to center, I get what I can only describe as a rubber-band like bounce, as if the plane was held in place by rubber bands.  is this realistic?

Give it a try in the MA, line your sight up with something and pull rudder and release to center. It's bizarre.  Do planes really do that?

:D


Sounds like your jstick is producing some nose bounce. ack ack posted a link back here some time ago for a stick scale profile with minimal nose bounce. If you can't find it, PM me with your e-mail address.

What stick are you using?

Offline scottydawg

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Realistic flight model?
« Reply #3 on: April 24, 2006, 02:12:46 PM »
I'm using a MS Sidewinder Pro Force Feedback on a game port.

Offline Max

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Realistic flight model?
« Reply #4 on: April 24, 2006, 03:02:34 PM »
Doht! Excuse my lack of SA for not having picked that up in your sig.

Geez, that's an old stick. You may have worn out pots. If your calibrating in Windows and AH and the axis lines are all smooth and lined up right in the joystick setup window you might try this: grab a plane offline and sit on the runway. Using your external views, move your ailerons, elevators and rudders around with your stick to see if they're smooth, and move accordingly with your joystick.

Ackack's stick profile can be found via this link:
http://www.hitechcreations.com/forums/showthread.php?s=&threadid=162256&highlight=ackack+stick+profile

place the stick.cfg file in your AH2 SETTINGS folder

If you're still having problems, it might be time for a new stick. Best Buy sells Saitek EVO's for $35

Good luck!

Offline scottydawg

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Realistic flight model?
« Reply #5 on: April 24, 2006, 03:08:31 PM »
Thanks, Max.

I took it apart last week to see, it's all optical. However, it is a bit twitchy, probably because the gameport/soundcard PCI bus is running faster than the stick was designed for. Other than that it's a decent stick... I've done the calibration and made the moves and there's no bounceback.

Offline Strykar1

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Realistic flight model?
« Reply #6 on: April 25, 2006, 01:13:39 PM »
Are you speaking of the sudden yaw snap when you center your rudder suddenly?

If so, I have a similar effect myself, Of course I am using a Logictech Attack 3 for a stick. I dont have a Twist on my stick so I programed three of my buttons to act as my Rudder controls (Left, Right, and Center)  And when ever I use my rudder and then Center it. It snaps my plane in a hard Snap, much like your Rubber Band comparison...

If that is the Case, Then I personally believe it would be something quite similar to a real aircraft. Of course... I have no personal experience in this my self, and I could be completely Wrong.


Stryker

Offline scottydawg

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Realistic flight model?
« Reply #7 on: April 25, 2006, 01:26:18 PM »
Quote
Originally posted by Strykar1
Are you speaking of the sudden yaw snap when you center your rudder suddenly?

If so, I have a similar effect myself, Of course I am using a Logictech Attack 3 for a stick. I dont have a Twist on my stick so I programed three of my buttons to act as my Rudder controls (Left, Right, and Center)  And when ever I use my rudder and then Center it. It snaps my plane in a hard Snap, much like your Rubber Band comparison...

If that is the Case, Then I personally believe it would be something quite similar to a real aircraft. Of course... I have no personal experience in this my self, and I could be completely Wrong.


Stryker


That's exactly it, a yaw snap where the plane wiggles twice. Same with elevator.  Maybe it is realistic, hell I've never flown a real prop fighter so I have no idea.

Offline Badboy

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Re: Realistic flight model?
« Reply #8 on: April 25, 2006, 04:25:16 PM »
Quote
Originally posted by scottydawg
I'm curious about the flight model, in particular the 'elevator bounce' and 'rudder wibble' (my words) I get when I fly.

For example if I move the elevators and release to center, I get what I can only describe as a rubber-band like bounce, as if the plane was held in place by rubber bands.  is this realistic?

Give it a try in the MA, line your sight up with something and pull rudder and release to center. It's bizarre.  Do planes really do that?

:D

Yes, and the correct term for what you describe as elevator bounce is a pitch oscillation. It is a normal characteristic of the control response and flight dynamics of an aircraft. There are other types, but what you are seeing is called a short period pitch oscillation. That type of oscillation is normally damped by the tail plane, and the degree of damping depends on the longitudinal stability, longitudinal dihedral, position of the center of gravity, the movement of the center of pressure on the main wing and fuselage, and the area, aspect ratio, angle and distance of the tail from the center of gravity. In most aircraft where the controls have low to moderate control power, and are handled gently, pitch oscillations are not significant. However, fighters are intended to respond quickly to their controls, they are generally less stable than other aircraft and their control power is relatively high and they have less pitch damping because that would reduce their transient maneuverability. The situation is further complicated because stability in roll, yaw and pitch all have an affect on each other. In the Aces High flight model that is accurately accounted for and the differential equations that describe the motion in one axis are coupled with those for the other two axis, and they are solved numerically as simultaneous differential equations providing a high degree of fidelity to real aircraft motion.  Even so, most real fighters are rarely handled in a way that causes them to behave badly in this respect. Real pilots don’t handle their controls sharply, by snatching the flight control backwards and then releasing them, if they did the pitch oscillations would be apparent, particularly at the lower end of the aircraft’s speed range. Real pilots tend to make control commands that are positive but steady, for flight sim pilots, who don’t suffer the same physical restraints, control movements and responses are inclined to be far more dramatic and for that reason, even though the aerodynamics may be exactly the same, the flight sim pilot may experience control responses, in terms of oscillations, that few real pilots would normally see.

The good news is that because this is a control response, it is something you have the ability to influence with good manual control technique. You simply don’t need to make sudden or sharp control demands. One area where this is particularly important is in the influence this has on gunnery. When you are trying to track a target and hold a guns solution, it is important to make smooth changes of direction so that you can minimize any oscillations that spoil your aim. That’s why it can often be easier to get a kill when the bandit is holding a steady turn, and also why a good guns defense involves sudden and frequent changes of direction. All of that is the same for both real and sim' pilots.

I have found from experience that the design of some flight controls actually exacerbate this affect, particularly when they allow you to generate large control movements in very short times. Other flight sticks ease the problem, and I’m also convinced it is not just the physical design of the stick at play, the electronic characteristics of the stick also has an influence on the control signals received by the game and my own experiments with many different sticks show that this can result in a difference in the stability of the aircraft observed in flight simulations.

Regardless of what stick you use the pitch oscillations can also be damped out to some extent in Aces High by using the control settings. However, too much pitch damping can have a negative affect on your reaction times in combat so it is important to find a stick that enables you to achieve a good degree of stability with as little pitch damping as possible.

Hope that helps…

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Offline Schatzi

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Realistic flight model?
« Reply #9 on: April 25, 2006, 04:45:51 PM »
Very interesting information Badboy. Thank you!


>S< Schatzi



PS: What kind of scares me is that i actually understood the first paragraph without having to read it twice :lol
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Offline scottydawg

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Realistic flight model?
« Reply #10 on: April 25, 2006, 05:01:53 PM »
Quote
Originally posted by Schatzi
Very interesting information Badboy. Thank you!


>S< Schatzi



PS: What kind of scares me is that i actually understood the first paragraph without having to read it twice :lol


Yeah, wow. That was a great post Badboy, thanks very much for that astute explanation. Didn't even make my brain hurt once.

Do you have any recommendations as to good sticks? The wife, bless her heart, has given me the okay to hurt the Amex for a new PC (and stick, I assume!).  She has no idea...

Offline Badboy

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Realistic flight model?
« Reply #11 on: April 25, 2006, 11:34:15 PM »
Quote
Originally posted by scottydawg
Do you have any recommendations as to good sticks?


Yep, I recommend CH gear. The usb version of the 568 Combatstick provides the best combination of in game stability and precision that I've seen. I use it in combination with their pro throttle.

The only down side is that it's a tad expensive, so if you know anyone with that equipment, it would be a good idea to try it out first.

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Offline Widewing

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Realistic flight model?
« Reply #12 on: April 26, 2006, 12:18:51 AM »
Quote
Originally posted by Badboy
Yep, I recommend CH gear. The usb version of the 568 Combatstick provides the best combination of in game stability and precision that I've seen. I use it in combination with their pro throttle.

The only down side is that it's a tad expensive, so if you know anyone with that equipment, it would be a good idea to try it out first.
 


I agree, CH Products is the way to go for the finest level of control. I have the FighterStick, Pro Throttle and Pro pedals. Not inexpensive, but very nice hardware. However, the CH gear is not without some issues.

One unhappiness was with the throttle. It has no tensioning device, which means that by simply resting one's hand on it, you can accidentally pull the engine out of WEP. Inasmuch as I'm a Design Engineer, I designed and built a simple spring detent that works well (but surely voided the warranty) by causing the throttle shaft to snap into the detent during the last 1/8th inch of travel and staying there until about 2 pounds of force is applied rearward. In my opinion, the lack of a tensioner is a design oversight. Every aircraft I've ever been in has a throttle tensioner or lock.

The FighterStick was designed for large hands. It is very awkward to reach the POV hat switch, requiring one to stretch one's thumb. I fixed that too, by machining a hand rest out of black Delrin (a machinable plastic) bar stock. I milled out the center to conform to the profile of the stick, split the piece, drilled tapped and counterbored it for two 6-32 screws. It simply clamps onto the stick. It raises my hand by 3/4 of an inch and provides a confortable rest. No more stretching for switch access.

Considering the initial cash layout, plus the time and effort fixing the deficencies of the stick and throttle, this was a rather costly investment.

There's an upside, and that is absolute precision and far better reliability than other manufacturer's hardware.

I strongly urge anyone considering CH Products gear to try it before you buy it. One exception would be for the Pro pedals. These are perfect right out of the box. You can use the Pro pedals with the X52 or X45 stick and throttle.

My regards,

Widewing
« Last Edit: April 26, 2006, 12:21:36 AM by Widewing »
My regards,

Widewing

YGBSM. Retired Member of Aces High Trainer Corps, Past President of the DFC, retired from flying as Tredlite.

Offline B@tfinkV

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Realistic flight model?
« Reply #13 on: April 26, 2006, 12:22:47 AM »
excelent post badboy, i was going to post the layman's version:



basically when youre pulling hard back on the stick the plane is not flying 'straight' through the air, more it is at a high angle of attack and pushing forwards from the belly and leading edge of the wing. When you then rapidly return the elevators to neutral the plane jerks back into a zero angle of attack forward motion, creating the bounce.


this is a very realistic flight characteristic, although in most civilian light aircraft you barely notice it, and you controls give you alot more space for smoother inputs, especialy in an aircraft with driect wired control setups suck as most older planes and almost all gliders.

a cheaper or less well made joystick in a simulation will great increase the problem.

I fly with a saitek cyborg setup with a small amount of deadband on each axis, the default sensitivity scale, and absolutely no damper anywhere.

on a cheap stick in particular over-dampening can make even basic flight a challenge

another get around for cheaper stick users is to manualy return the stick to neutral instead of letting it spring back. you would do this without thinking it using a real stick or yoke, you would very rarely let the controls pull themself back to neutral, certainly not infront of an instructor.
« Last Edit: April 26, 2006, 12:33:01 AM by B@tfinkV »
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Offline Simaril

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Realistic flight model?
« Reply #14 on: April 26, 2006, 08:08:37 AM »
Quote
Originally posted by Widewing

...snip...

The FighterStick was designed for large hands. It is very awkward to reach the POV hat switch, requiring one to stretch one's thumb. I fixed that too, by machining a hand rest out of black Delrin (a machinable plastic) bar stock. I milled out the center to conform to the profile of the stick, split the piece, drilled tapped and counterbored it for two 6-32 screws. It simply clamps onto the stick. It raises my hand by 3/4 of an inch and provides a confortable rest. No more stretching for switch access.

.....snip.....


I strongly urge anyone considering CH Products gear to try it before you buy it. One exception would be for the Pro pedals. These are perfect right out of the box. You can use the Pro pedals with the X52 or X45 stick and throttle.

My regards,

Widewing



Widewing,

Thanks for the excellent information. I'm using the Saitek X52, and have absolutlely loved the spring sensitivity, controllability, and responsiveness. I found immeditae improvements in smooth flight control, and especially in fine gunnery. I've also loved the CH pedals, right out of the box.

In fact, if anyone's looking for a good stick/throttle combo but isnt ready for the CH plunge,  I highly recommend X52. The only caveat: with extensive AH use (I play about 50hrs per month) I've had Saitek products show some wear after 10-12 months. (experience was with the X45, not sure baout the X52) I very happily bought the BestBuy product warranty, adn traded my X45 in each time a hat stopped responding quickly.....so for my one purchase, I got 2 straight up replacements, and was able to upgrade to the X52 for the 3rd when the X45 left production for only an extra $30. This time, I didnt get the wrranty because I've planned to take the CH plunge for my next stick.


Now for a question I've never asked another man.  

What's the distance from your wrist crease to the tip of your middle finger? :lol

I dont have ready access to a Fighterstick to try for comfort, and if my hand's the same size as yours I might have a problem.....
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