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DeepCove68
06-22-2005, 04:43 AM
Trim Myths.

First let€s look at two types of elevator trim systems
1. Trim on prop planes including war time planes and modern small light aircraft.

Trim is usually controlled by a wheel in the cockpit turned by hand and takes time to operate throughout it€s range. The wheel controls a small trim tab on the elevator which sticks in to the airflow and exerts a force on the elevator to keep it in position. When the plane is trimmed for a given flight condition the elevator will still be deflected in relation to the horizontal stabilizer(stab) aka horizontal tail plane. If the aircraft is trimmed in a nose up condition then consequently the elevator will be up and the stick in the cockpit will be back in the pilot€s belly. The trim tab keeps the elevator there by aerodynamic force.
Elevator authority in this case is limited and as the elevator is up, drag is increased.

2. Trim on modern large aircraft.

Due to large variations in payload weight and distribution and a large speed range modern large aircraft need a different system. This is the trimmable horizontal stabilizer THS.
In this system the trim is applied by moving the whole horizontal tail plane. When the plane is trimmed the elevator is inline with the horizontal stabilizer. Drag is minimized (saving fuel costs on those long cruise segments)and full elevator authority available. The stick is in a neutral position in the cockpit. This system is not found on wartime prop planes to my knowledge.

What does this mean in FB/AEP/PF ?

You should NOT be able to go faster by being in trim as the elevator is not necessarily in line with the horizontal stabilizer and is creating the same drag as it would if it were not trimmed.

Selecting extra nose up trim in a turn should not give a tighter turn as, in system 1 above; there is NO change in elevator authority with a change in trim.
The only benefit to nose up trim in a turn would be to reduce the stick force needed by the pilot. Stick forces are not modelled in this game (maybe a moderator knows???)

Trim takes time to apply but is applied instantaneously. I believe the little trim wheels in cockpit view spin a little too fast.


A little paper on prop pitch and over boosting engines to follow soon *.


Please discuss

Regards Deep Cove
Degree Mechanical Engineering (Hons)
ATPL holder 5500 hrs A319/320/321

DeepCove68
06-22-2005, 04:43 AM
Trim Myths.

First let€s look at two types of elevator trim systems
1. Trim on prop planes including war time planes and modern small light aircraft.

Trim is usually controlled by a wheel in the cockpit turned by hand and takes time to operate throughout it€s range. The wheel controls a small trim tab on the elevator which sticks in to the airflow and exerts a force on the elevator to keep it in position. When the plane is trimmed for a given flight condition the elevator will still be deflected in relation to the horizontal stabilizer(stab) aka horizontal tail plane. If the aircraft is trimmed in a nose up condition then consequently the elevator will be up and the stick in the cockpit will be back in the pilot€s belly. The trim tab keeps the elevator there by aerodynamic force.
Elevator authority in this case is limited and as the elevator is up, drag is increased.

2. Trim on modern large aircraft.

Due to large variations in payload weight and distribution and a large speed range modern large aircraft need a different system. This is the trimmable horizontal stabilizer THS.
In this system the trim is applied by moving the whole horizontal tail plane. When the plane is trimmed the elevator is inline with the horizontal stabilizer. Drag is minimized (saving fuel costs on those long cruise segments)and full elevator authority available. The stick is in a neutral position in the cockpit. This system is not found on wartime prop planes to my knowledge.

What does this mean in FB/AEP/PF ?

You should NOT be able to go faster by being in trim as the elevator is not necessarily in line with the horizontal stabilizer and is creating the same drag as it would if it were not trimmed.

Selecting extra nose up trim in a turn should not give a tighter turn as, in system 1 above; there is NO change in elevator authority with a change in trim.
The only benefit to nose up trim in a turn would be to reduce the stick force needed by the pilot. Stick forces are not modelled in this game (maybe a moderator knows???)

Trim takes time to apply but is applied instantaneously. I believe the little trim wheels in cockpit view spin a little too fast.


A little paper on prop pitch and over boosting engines to follow soon *.


Please discuss

Regards Deep Cove
Degree Mechanical Engineering (Hons)
ATPL holder 5500 hrs A319/320/321

Ruy Horta
06-22-2005, 04:52 AM
Following your description the Bf 109, Fw 190 and Me 262 used "modern" trim systems.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">This system is not found on wartime prop planes to my knowledge </div></BLOCKQUOTE>

Guess it is time for a rethink...

Oilburner_TAW
06-22-2005, 05:24 AM
This has always been my problem with il-2's trim system. Using a CH stick you can trim the stick itself (outside of the game) or use the in-game trim control. There should be a net 0 effect on speed. However, this is not the case.

ElAurens
06-22-2005, 05:35 AM
Not exactly a rethink, as the vast majority of WW2 era aircraft that have trim use the system like DeepCove68 describes, and even the German aircraft use a wheel and chain system to operate their trim setup. So trim will still take some time to dial in on a real aircraft as there has to be some "gear reduction" on the trim wheel to allow for enough mechanical advantage agianst the pressure of airflow at speed.

To wit, you cannot go from level (or no) trim to full up or down in an instant like you now can in the sim.

Looks like the old trim bug is back. Can RBJ be far behind?

http://forums.ubi.com/images/smilies/51.gif

DeepCove68
06-22-2005, 05:40 AM
I stand corrected in the 109 and 190.Did all versions have moveable stabs.What about the 109E with the struts or did the tail move with the struts attached
Are there any allied planes that have a trimmable horizontal stab that you know of Horta?
Must admit I was surprised to find photos of trimmable stab on these old planes.

VF-29_Sandman
06-22-2005, 05:49 AM
so does this mean that the german's were pioneer's in the way moderen planes now trim? hmmm mebby

VW-IceFire
06-22-2005, 08:19 AM
My question is why did they neglect rudder trim if it was seemingly so important to maintain an aircraft in straight and level flight. What must a virtual pilot do to keep the plane trimmed level.

Except in US build aircraft, you just cannot trim for level and walk away to get a drink anymore.

VF-19
06-22-2005, 09:13 AM
I find the new trim settings quite nice. The main advantage I find that it works faster, which is really useful when you start in the air for some campaign missions or in quick missions.

Also, since I only have 2 rotaries on my X-45, the quicker response makes trimming rudder really easy, as it's assigned to the keyboard.

And besides, when I'm getting shot at, I'm not really concerned with using the trim to give myself an advantage, as I'm more concerned with saving my precious behind.

And then even if I would use the trim to my advantage (if it works), I'd be in a disadvantage afterwards as the plane would be out of trim, ruining my shot.

jarink
06-22-2005, 10:14 AM
Read the title and thought this was about mythylogical trims exploding.

My joystick's rudder is out of whack requiring me to trim to make up for it (even with adjusted joystick settings). Really stinks flying planes without rudder trim.

I don't find this to be too much of an issue considering there are so many 'cheats' regarding trim since this is a computer game. There's "trim on a slider", joystick settings (can't adjust stick sensitivity on most planes, warbird or no, that I've ever seen), and the joysticks themselves. HOTAS in a Hurricane? Not hardly.

Still, interesting arguments, especially concerning speed.

LEXX_Luthor
06-22-2005, 11:36 AM
ElAurens:; <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">To wit, you cannot go from level (or no) trim to <span class="ev_code_yellow">full up or down</span> in an instant like you now can in the sim.

Looks like the old trim bug is back. Can RBJ be far behind? </div></BLOCKQUOTE>
FB/PF trim was not made for slider use. You can't do instant trim if you don't map trim to a slider. Realistic flight models require fast acting trim over small trim adjustments for proper control of aircraft. Anyway, according to the more reliable posters here and at simhq, the RBJ slider trim exploit no longer works after Patch 4.01. I dunno.

Deepcove:: <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The only benefit to nose up trim in a turn would be to reduce the stick force needed by the pilot. Stick forces are not modelled in this game (maybe a moderator knows???) </div></BLOCKQUOTE>
Nose down trim is the same way. A certain amount of stick forces are modded by Default by the simple requirement of gaming hardware. Without trim, you must hold the stick or rudder off center. That means you exert force on your hardware. With trimming, you can let go of the stick or rudder and maintain constant flight attitudes.


If Slider trim still allows cheaters using slider trim during the Online Dogfight, then I suggest Oleg make elevator trim a Server Option that can be turned OFF when the Dogfight begins.

DeepCove68
06-22-2005, 11:54 AM
Stick Forces could be moddelled in one way.
High stick loads sap strengh over time. I remember in the free demo of Fighter Ace that came with the CFS2 CD that a Heartbeat noise could be heard at high G. Perhaps some simillar noises including deep breathing could be incorporated to the sim to simulate fatigue from to much G loads in sustained turn fight and high stick and rudder forces. As breathing and fatigue becomes stronger the effect of your controls is reduced UNLESS your trimmed.
Just a thought
DeepCove

LEXX_Luthor
06-22-2005, 12:06 PM
A certain amount of stick forces are modded by Default by the simple requirement of gaming hardware. Without trim, you must hold the stick or rudder off center. That means you exert force on your hardware. With trimming, you can let go of the stick or rudder and maintain constant flight attitudes.

irR4tiOn4L
06-22-2005, 12:08 PM
funny that - i still dont know how to use trim in the sim, as i never use it while flying - i simply maintain control over the stick and twist rudder at all times. Maybe i should learn how to use it?

LEXX_Luthor
06-22-2005, 12:15 PM
Irational:: <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">funny that - i still dont know how to use trim in the sim, as i never use it while flying - i simply maintain control over the stick and twist rudder at all times. Maybe i should learn how to use it? </div></BLOCKQUOTE>
Mee Too before New FM. We never needed to learn how to use trim before New FM for two reasons...

(1) Old FM simply did not need much trim. Some, but not this much.

(2) Old FM trim controls were disabled in an attempt to prevent Online cheating, so the little trim that was needed by Old FM was best ignored as it was easier to just compensate by directly exerting stick/rudder forces.

Tully__
06-22-2005, 12:36 PM
I'll have to test... I'll be home from work in about 4 hours. I'll try & post results later in the day.

Ruy Horta
06-22-2005, 12:52 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DeepCove68:
I stand corrected in the 109 and 190.Did all versions have moveable stabs.What about the 109E with the struts or did the tail move with the struts attached
Are there any allied planes that have a trimmable horizontal stab that you know of Horta?
Must admit I was surprised to find photos of trimmable stab on these old planes. </div></BLOCKQUOTE>

Deep Cove,

Like someone else pointed out the fact that you made a slight mistake doesn't mean you do not have a point "in general".

I honestly wouldn't know of any Allied types, but yes also the Emil employed this system.

From a ready at hand source (and as such not infallible data) the range of tail trim on an Emil was +3 to -8 dgr.

DeepCove68
06-22-2005, 03:27 PM
Horta
I must admit I was a little embarrased to learn about trimmable stabs on 109/190. Should have done more research.What source are you using ?
If it's a net link I'd be interested to have a look?
Thanks Deep Cove

TX-EcoDragon
06-22-2005, 03:55 PM
Originally posted by DeepCove68:
Trim Myths.

First let€s look at two types of elevator trim systems
1. Trim on prop planes including war time planes and modern small light aircraft.

Trim is usually controlled by a wheel in the cockpit turned by hand and takes time to operate throughout it€s range. The wheel controls a small trim tab on the elevator which sticks in to the airflow and exerts a force on the elevator to keep it in position. When the plane is trimmed for a given flight condition the elevator will still be deflected in relation to the horizontal stabilizer(stab) aka horizontal tail plane. If the aircraft is trimmed in a nose up condition then consequently the elevator will be up and the stick in the cockpit will be back in the pilot€s belly. The trim tab keeps the elevator there by aerodynamic force.
Elevator authority in this case is limited and as the elevator is up, drag is increased.

2. Trim on modern large aircraft.

Due to large variations in payload weight and distribution and a large speed range modern large aircraft need a different system. This is the trimmable horizontal stabilizer THS.
In this system the trim is applied by moving the whole horizontal tail plane. When the plane is trimmed the elevator is inline with the horizontal stabilizer. Drag is minimized (saving fuel costs on those long cruise segments)and full elevator authority available. The stick is in a neutral position in the cockpit. This system is not found on wartime prop planes to my knowledge.

__________________________

No??? You might wanna take a closer look at the LW aircraft. . . and the Piper Cub.
__________________________

What does this mean in FB/AEP/PF ?

You should NOT be able to go faster by being in trim as the elevator is not necessarily in line with the horizontal stabilizer and is creating the same drag as it would if it were not trimmed.

_________________________
Um, no, you will go faster when in trim as there is much more to it than localized drag on the surface/tab itself, the entire aircraft will present a different frontal area depending on trim configuration of the rudder and aileron rigging, as well as different angle of attack on each surface, additionally given the constant PIO that you will encounter if the elevator is out of trim you will also have an overall increase in induced drag and decreased efficiency. Trim while watching GPS ground speed and it's pretty darn obvious, in particular when at higher speeds, but even in a 115 knot cruiser a 5 knot increase is common when going from climb rudder trim to cruise rudder trim.
___________________________________________

Selecting extra nose up trim in a turn should not give a tighter turn as, in system 1 above; there is NO change in elevator authority with a change in trim.

__________________________________

Not so. In an aircraft or flight regime where stick forces are high a reduction in stick forces as provided by trim will obviously increase the G available to the pilot since the lbs/G is decreased in doing so.

__________________________________

The only benefit to nose up trim in a turn would be to reduce the stick force needed by the pilot. Stick forces are not modelled in this game (maybe a moderator knows???)

________________________________________

Stick forces are modeled in the sim, have you flown the 109? Try flying it and notice the feel as you increase speed, in particular on the pitch axis.

________________________________________

GazeH0und
06-22-2005, 07:13 PM
Bah, was hoping to read about mythical exploding trim..
oh well http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

LEXX_Luthor
06-22-2005, 07:13 PM
Thanks TX, that explains much.

TX:: <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">...you will go faster when in trim as there is much more to it than localized drag on the surface/tab itself, the entire aircraft will present a different frontal area depending on trim configuration of the rudder and aileron rigging, as well as different angle of attack on each surface, additionally given the constant PIO [..Pilot Induced Oscillations..] that you will encounter if the elevator is out of trim you will also have an overall increase in induced drag and decreased efficiency. Trim while watching GPS ground speed and it's pretty darn obvious, in particular when at higher speeds, but even in a 115 knot cruiser a 5 knot increase is common when going from climb rudder trim to cruise rudder trim. </div></BLOCKQUOTE>
I never thought that much of this, and Ya out of trim I always do constant over-corrections back and forth or "PIO." I learned something today. Also, always over-correcting is frustrating, and physically tiring to the real pilots I guess.

Thanks~~!!~~!!!

NonWonderDog
06-22-2005, 07:46 PM
Flying out of trim will of course be slower, but what if you happen to have the Iron Grip of Doom(tm) and manage to hold the plane perfectly in trim without touching the wheels? I can't really see how it would be much different than using the trim tabs. Keeping the tabs level with the control surface seems like it could reasonably be the least draggy position, too.

Now, obviously, no one could do this without inducing small oscillations and no decent pilot should even think about it if there's a trim wheel right there... but it's very possible in the sim. It's especailly possible if you have a joystick with hardware trim.

If one uses hardware trim on their joystick and rudder control instead of the in-sim trim controls, will they actually be slower? Should they be slower?

Nimits
06-22-2005, 08:57 PM
Without getting into aerodynamic arguments, the trim we have with 4.01m (and the amount required to keep the plane in trim) corresponds much, much, much more closely to my actual flight experiance than 3.04m. 3.04m was not at all realistic in its implementation of trim.

gates123
06-22-2005, 11:21 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VW-IceFire:

Except in US build aircraft, you just cannot trim for level and walk away to get a drink anymore. </div></BLOCKQUOTE>

Not true all planes can be trimmed out to perfection barring any rpm or speed changes. German planes especially trim out nice when the rpm's are set to economy revs. Take a 109 or 190 to altitude and level out after the elevator is trimmed and their roll due to torque will balance out at around 35-50% throttle depending on airspeed. I went downstairs to get a glass of water once and my A6 didnt move while i was gone. Gotta find the sweet spots in the rpm to fix the aileron roll but it would be nice if we could change the trim on the ground for higher rpm's

LEXX_Luthor
06-23-2005, 12:02 AM
Dude/Dudette, setting trim before flight. What a great idea. Oleg should add a trim setting next to the gun convergence. For planes that had controllable trim, this will be ignored. Awsum.

Ruy Horta
06-23-2005, 12:53 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DeepCove68:
Horta
I must admit I was a little embarrased to learn about trimmable stabs on 109/190. Should have done more research.What source are you using ?
If it's a net link I'd be interested to have a look?
Thanks Deep Cove </div></BLOCKQUOTE>

Using various sources, incl. my memory, but not the Internet (which I only trust when it comes to primary source material). The Bf 109 and Fw 190 feature relatively frequently in my book collection (and primary document collection).

The ready at hand source I used for the Emil numbers was:

Aero Detail 1
Messerschmitt Bf 109E
Shigeru Nohara & Masatsugo Shiwaku
Dai Nippon Kaiga, 1995
ISBN 4-499-20593-X

Regards,

Tully__
06-23-2005, 01:38 AM
Stick forces are modelled in this sim. The sim equates joystick input as pounds force on the stick, not a certain angle of deflection. Where aircraft speed is high enough that the maximum available deflection force is not sufficient to fully deflect the controls, trim should help with turning.

The only time trim shouldn't help with turning or pulling out of dives is when the speed is below that where aerodynamic resistance to elevator movement exceeds maximum available stick force.

Nimits
06-23-2005, 01:49 AM
Of course in real planes, using trim to assist elevator authority, even if it worked, was highly discouraged, as it tended to break things . . .

DeepCove68
06-23-2005, 02:31 AM
"Trim while watching GPS ground speed and it's pretty darn obvious, in particular when at higher speeds, but even in a 115 knot cruiser a 5 knot increase is common when going from climb rudder trim to cruise rudder trim"

Let's not mix the issue of flying out of trim with flying out of balance. If you manage to keep your wing level and the ball in the middle with rudder as you level off, accelerate and then set cruise power and assuming you have strong thighs wether you
r trimmed or not makes no difference to frontal area No??
Lets also assume for this discussion that the pilot can maintain the stick force out of trim and not PIO.
Tully thanks for getting back to us about about stick force modelling in the sim.

TX-EcoDragon
06-23-2005, 04:03 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NonWonderDog:
Flying out of trim will of course be slower, but what if you happen to have the Iron Grip of Doom(tm) and manage to hold the plane perfectly in trim without touching the wheels? I can't really see how it would be much different than using the trim tabs. Keeping the tabs level with the control surface seems like it could reasonably be the least draggy position, too.

Now, obviously, no one could do this without inducing small oscillations and no decent pilot should even think about it if there's a trim wheel right there... but it's very possible in the sim. It's especailly possible if you have a joystick with hardware trim.

If one uses hardware trim on their joystick and rudder control instead of the in-sim trim controls, will they actually be slower? Should they be slower? </div></BLOCKQUOTE>

Yep, gotta give ya that, and there are some aircraft with such light controls that trim is hardly needed (I rarely touch trim in the Extra, and even when I do it's just for a little added precision that I would be fine without in all honesty) but these aircraft in this sim, and most aircraft are going to be a chore to fly if too far out of trim, and since we are talking about these aircraft leaving trim alone should be a rather obvious mistake in any of these aircraft. In aerobatic aircraft that have heavy controls I often fly acro sequences using "neutral trim" instead of trimming away pressures, this trim is left alone the entire time, and is set generally by noting the trim position when upright at cruise speed, then rolling inverted and trimming for that attitude, and then splitting the difference between the two trim positions, this means that I fly most of the time with constant backpressure required, it does make drawing a horizontal competition line a little bit tough since there is usually some slight correcting required to find the correct position, but the pay off is in the vertical lines and the 45's with half or point rolls on them where the equivalent force forward and aft makes drawing the perfect 45 before and after the roll a bit easier. That said, there is always some decrease in the quality of the level lines since its pretty darn near impossible to hit that perfect spot with the controls when holding a bunch of pressure. Gunnery in this situation in the much heavier controls of most of these WWII fighters would be quite a pain if done in such a trim configuration, and the flying is rather tiring if done this way as well.

TX-EcoDragon
06-23-2005, 04:13 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DeepCove68:
"Trim while watching GPS ground speed and it's pretty darn obvious, in particular when at higher speeds, but even in a 115 knot cruiser a 5 knot increase is common when going from climb rudder trim to cruise rudder trim"

Let's not mix the issue of flying out of trim with flying out of balance. If you manage to keep your wing level and the ball in the middle with rudder as you level off, accelerate and then set cruise power and assuming you have strong thighs wether you
r trimmed or not makes no difference to frontal area No??
Lets also assume for this discussion that the pilot can maintain the stick force out of trim and not PIO.
Tully thanks for getting back to us about about stick force modelling in the sim. </div></BLOCKQUOTE>

Well, the assumption can be made, and in the real world in some aircraft like a 152/172 that's often how it's done since we can feel some slip and skid, and of course use the inclinometer to augment the seat of the pants, and not have too much force required to hold it, but even in the 172 at high cruise speeds the constant left rudder that's usualy required often get's tiring after a little while. I guess I don't really see the point in setting those conditions since they don't really apply in particular to these aircraft. . . believe me you get a real tired leg if you leave the rudder in something like the P-51 in the takeoff trim position, you WILL be slacking after a little while. . .bodybuilder or otherwise.

In the end, in the real world, a fully trimmed aircraft will pretty much always have the advantage (despite a slight increase in drag at the trim tab itself), in speed, balanced handling, gunnery platform-wise, and with respect to pilot fatigue. . . so I don't really feel that any issues were being mixed since they aren't really separable in the first place in these machines especially.

AerialTarget
06-23-2005, 05:38 AM
Ah! But trimming the airplane will not, in itself, make the airplane go faster in real life. Is this not true?

Bearcat99
06-23-2005, 06:12 AM
One thing about trim in 4.01.... now i understand what being "on the ball" is all about.....

Aaron_GT
06-23-2005, 06:24 AM
Without trim you need to be able to control the aircraft with small, constant inputs. With the problems in feedback in PC sticks it's hard to do this accurately and so the tendency is to overcorrect, followed by undercorrection, and so on. This would add a fair bit of drag. So even with trim systems as DeepCover suggests trimming correctly is likely to lead to less drag over time than trying to manually correct in the sim.

RxMan
06-23-2005, 07:06 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The only time trim shouldn't help with turning or pulling out of dives is when the speed is BELOW that where aerodynamic resistance to elevator movement exceeds maximum available stick force. </div></BLOCKQUOTE>

Trying to get this line TULLY, shouldn't that be OVER or ABOVE the max aero resistance speed.

TX-EcoDragon
06-23-2005, 12:59 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by AerialTarget:
Ah! But trimming the airplane will not, in itself, make the airplane go faster in real life. Is this not true? </div></BLOCKQUOTE>

Well, if you leave trim at the takeoff setting and set max cruise power how fast are you going to go?? The answer is whatever climb speed takeoff trim equates to and that's obviously a lot slower than max speed, so if you aren't forcing the stick forward to oppose the forces imposed by the trim then yes, trimming to cruise speed will *in itself* make the aircraft go faster, since in truth thats what trim does, it's a means for selecting the airspeed of the aircraft will fly when left to it's own devices, with throttle controlling the condition of flight, ie climb cruise or descent.

TX-EcoDragon
06-23-2005, 01:11 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Aaron_GT:
Without trim you need to be able to control the aircraft with small, constant inputs. With the problems in feedback in PC sticks it's hard to do this accurately and so the tendency is to overcorrect, followed by undercorrection, and so on. This would add a fair bit of drag. So even with trim systems as DeepCover suggests trimming correctly is likely to lead to less drag over time than trying to manually correct in the sim. </div></BLOCKQUOTE>

Yes, and to an even greater degree in the real world were there is generally more induced drag from the slip/skid condition as well as the drag induced by deflected surfaces that we also lack in the sim, and of course high stick forces that generally would be very fatiguing to maintain . . .in the sim its not a problem to fly around with the stick held forward since there is very little force in any desktop joysticks.

TX-EcoDragon
06-23-2005, 01:35 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RxMan:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The only time trim shouldn't help with turning or pulling out of dives is when the speed is BELOW that where aerodynamic resistance to elevator movement exceeds maximum available stick force. </div></BLOCKQUOTE>

Trying to get this line TULLY, shouldn't that be OVER or ABOVE the max aero resistance speed. </div></BLOCKQUOTE>

he said the only time trim *wouldn't* help is when speed is low enough that the pilot strength model is capable of pulling the full available G of the aircraft, in something like the 109 when stick forces go up particularly high if the pilot can only pull (as an example) 80 lbs of force and the stick pressures are 20 lbs per G at say 500 kph the pilot can only pull 4G with only partial elevator travel, down at 300 kph suppose the stick forces are now 10 lbs/G the pilot can pull 8G with the full range of elevator travel. Clearly there is little need for any additional trim when the available G is 8G.

Tully__
06-23-2005, 07:23 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RxMan:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The only time trim shouldn't help with turning or pulling out of dives is when the speed is BELOW that where aerodynamic resistance to elevator movement exceeds maximum available stick force. </div></BLOCKQUOTE>

Trying to get this line TULLY, shouldn't that be OVER or ABOVE the max aero resistance speed. </div></BLOCKQUOTE>

There is a speed above which the maximum force the pilot can apply to the stick is not sufficient to achieve maximum control input ('cept in aircraft with power assisted controls). Above that speed trim will help, as trim adds aerodynamic force to the pilot force when set to do so. Below that speed, trim shouldn't add to control input as the pilot can achieve max input without the aid of trim.