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XyZspineZyX
10-24-2003, 03:05 PM
I need to know how many turns a real-world trim wheel makes, or how many degrees of arc the trum-wheel turns, or HOWEVER this question should be formated.

Are we talking 1 single turn of trim to go from one extreme to another, or did the trim wheels turn multiple rotations to go from extreme deflections?

Thanks.

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XyZspineZyX
10-24-2003, 03:05 PM
I need to know how many turns a real-world trim wheel makes, or how many degrees of arc the trum-wheel turns, or HOWEVER this question should be formated.

Are we talking 1 single turn of trim to go from one extreme to another, or did the trim wheels turn multiple rotations to go from extreme deflections?

Thanks.

<font face="Courier New">

‚ ‚ ‚ ‚ ‚ ‚ _____ | _____
‚ ‚ ‚ ‚ ‚ ‚ ‚ _\__(o)__/_
‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ./ \.

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XyZspineZyX
10-24-2003, 03:14 PM
By the way: this has nothing to do with past trim arguments!

I need to know what type of dial to use in my cockpit project. If it takes multiple turns to trim, I'll use reduction gears or something (maybe 20-turn potentiometers so i can fly with precision!).

Thanks.

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‚ ‚ ‚ ‚ ‚ ‚ _____ | _____
‚ ‚ ‚ ‚ ‚ ‚ ‚ _\__(o)__/_
‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ./ \.

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XyZspineZyX
10-24-2003, 03:20 PM
Good luck Baldie, sounds like a great project.

Every CIVILIAN a/c and some airforce cargo a/c that I have flown have multiple turns. Some as few as 3, some more than 10. As far as WWII fighters? I don't know.


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XyZspineZyX
10-24-2003, 03:53 PM
It seems i can get 3, 5, 10, and 20-turn potentiometers. I think i'm going to use 5-turn pots with these dials:

http://www.potentiometers.com/images/ehindPDC1.jpg

Kinda cool looking... similar to the real thing.

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‚ ‚ ‚ ‚ ‚ ‚ _____ | _____
‚ ‚ ‚ ‚ ‚ ‚ ‚ _\__(o)__/_
‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ./ \.

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Message Edited on 10/24/0310:54AM by BaldieJr

XyZspineZyX
10-24-2003, 04:43 PM
I don't know about WW2 aircraft trim, but I'm going to suggest that they required mutliple turns as otherwise the trim could be controlled by a lever rather than a wheel... but, again, I'm just speculating here.

XyZspineZyX
10-24-2003, 07:35 PM
I guess it depends on the aircraft... What type are you looking for?

rgds

XyZspineZyX
10-24-2003, 07:46 PM
jmmoric wrote:
- I guess it depends on the aircraft... What type are
- you looking for?
-
- rgds
-
-

It doesnt matter really, I'm not modeling any particular pit. I'm more concerned with a functional 'generic' pit since I fly several different planes in several different sims.

At best, i'll have a few of the important guages and a hand-full of switches. Trim, throttle, mixture, prop pitch will all be in there too... nothing major as i'm on a budget.

<font face="Courier New">

‚ ‚ ‚ ‚ ‚ ‚ _____ | _____
‚ ‚ ‚ ‚ ‚ ‚ ‚ _\__(o)__/_
‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ‚ ./ \.

</font>

XyZspineZyX
10-24-2003, 07:46 PM
I too think multiple turns, though I haven't a clue where to look up a reference confirmation.

XyZspineZyX
10-24-2003, 08:24 PM
This is an excellent question. I can tell you that in civilian aircraft, the ratio is such that you have to turn the wheel quite a bit to enact much change. This is as one might expect, since trim is designed for fine tuning pitch, roll, and yaw.

Of course, knuckle-draggers like RBJ will argue that you should be able to go from one extreme of the trim wheel to the other in the time it take you to move a video game joystick slider from front to back (as fast as 1/10 of a second), but I have never heard of any plane being able to do anything remotely approximating this.

I believe this is why they included the time lag for trim effect in the game.

XyZspineZyX
10-25-2003, 12:22 AM
Cessna 172's and 152"s the trim wheel has to be rotated in half turns at least 10x from one extreme to the other

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XyZspineZyX
10-25-2003, 02:23 AM
Many aircraft that have trim wheels require multiple turns to go from stop to stop, though another common type of trim is the trim lever, and this may move forward and back about 8 inches, or another common WWII type rotates only 180 degrees from stop to stop. Under most circumstances you will not need to use the extremes of the trim deflection, but you do want to be able to have fine control over the trim tab.

What type of aircraft are you attempting to emulate?


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XyZspineZyX
10-25-2003, 03:11 AM
Multiple turns. The low rotation to effect ratio is necessary for them to be useful in fine-tuning control surface pressures.

Baldie, it's your call about what you want to use for the trim controls, but most warbirds (on all sides) used controls similar to these:

http://www.flinstone.it/images/walkaround/p40greg/L%20side%20cockpit.jpg

The coffee-cup sized dials there are the trim dials. P-40, P-39, P-38, P-47, P-51, Yaks, LAs, and Fw-190s all used something pretty similar for at least some of their trim axis.

Stenciled on the side of my Dora:

"Lasst das H√¬∂llentor √¬∂ffen, es friert hier oben!"
("Leave the gates to Hell open, it's FREEZING up here!")

XyZspineZyX
10-25-2003, 03:42 AM
There was no doubt variation from one warbird to another as far as how many turns in a trim wheel. Sso I'd just go with some value that would make it a fine enough adjustment but
not too fine.

"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." Benjamin Franklin - 1755

SeaFury
10-25-2003, 03:45 AM
In the piper and cessna aircraft I have flown both the trim wheels and the trim turn handles require many many turn for full stop to full stop. I have seen aircraft with as many as 12-14 turns.

You correct in sawing trim is set in slowly and can be highly fine tuned. I have actually flown from one aerodrome to another with nothing more than rudder and the trim wheel. You can get all the way to the landing flare before you have to use the control stick. Even then you don't really need to, but it is the smart thing to do.

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