Real 737 yoke roll angle?

[Flying_Fox]

Hi All,

I wonder who can tell the exact  real 737 yoke roll angle. On different yoke design samples here I see the angle (to one side) from 45 to 90 degrees, on a real 737 controls check video (time around 3:30) it looks something like 80 degrees (? - definitely less then 90).

ANA Boeing 737 Cockpit view for Take off 

Mike? 

Thanks,
Nick

[N737AG]

They can actually rotate 90 degrees in each direction


Axel

[sluyt050]

PMDG modelled their NGX about max. - + 45 deg. Doesn't seem guesswork to me.

[archen]

Look at some videos when they perform checklists. When they do the controls checklist I does look like +-90 degrees..

I'll check if I can find a video. I Think I have one on dvd

Anders

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[Nat Crea]

I would definitely go with Axel and the video over PMDG, looks like +/- 90

Nat

[mickc]

The actual mechanical range of motion of the aileron control wheel mechanism is mechanically limited to 107.5 degrees each way.
This motion is reduced due to the range of motion of the aileron PCUs to around 88 degrees.

So around 90 degrees is correct. 

The PMDG model shows around half of the yoke movement compared to the real aircraft.

Even the control wheel movement for the aileron trim is almost 30 degrees each way (57 degrees total) so 45 degrees is nowhere near full aileron deflection.

[Flying_Fox]

Thanks Mick for the detailed reply!

88 degrees - thats' what I suspected looking at the video having slightly less than 90 degrees turn.

Thanks to everybody else who contributed!

Nick

[Aerosim Solutions]

Hi all, I set up my real yokes for 90 degrees each way which was a guess so I am pleased to see it confirmed here!
Cheers Gwyn

[Sudden81]

http://www.youtube.com/watch?v=xh5mq0-LnnQ

[sluyt050]

Interesting comments and video. So, apparently 90 deg. is realistic. I am wondering what that means in practice? Is there any captain among us who can confirm that a 90 deg. deflection is really used in flight? If so, I may hope passengers are not enjoying their meals at that very moment...

[Flying_Fox]

Interesting comments and video. So, apparently 90 deg. is realistic. I am wondering what that means in practice? Is there any captain among us who can confirm that a 90 deg. deflection is really used in flight? If so, I may hope passengers are not enjoying their meals at that very moment...

Yeah, I would also like to know what maximum angle is typically used in flight, set aside the emergencies...

[Sudden81]

But is that realy a interesting question"how mush is used in flight"?

I fly real planes and very seldom u use full deflection but the range is interesting also to me as a simulator builder. Because that tells you how you need to build your  column and setup pots and gears. It also tells you a little bit of how sensitive the plans controls is.

Sadly I did not know that when I build my column! But some day I will re build it!

[archen]

As Sudden already told you. Even if full deflection is not used very much in real world you will be loosing resolution and sensitivity if not using the full travel. If 45 degrees equal with full deflection, then 22,5 degrees would equal with 50% deflection. In the real plane 22,5 degrees would equal with 25% deflection. In the end you will have to turn the wheel half as much as in the real plane to get the same deflection.


How much this really affect in the end I don't know. Just a theoretical example. Sim will always differ from the real plane, many more factors play a major role in this.

[sluyt050]

As Sudden already told you. Even if full deflection is not used very much in real world you will be loosing resolution and sensitivity if not using the full travel. If 45 degrees equal with full deflection, then 22,5 degrees would equal with 50% deflection. In the real plane 22,5 degrees would equal with 25% deflection. In the end you will have to turn the wheel half as much as in the real plane to get the same deflection.


How much this really affect in the end I don't know. Just a theoretical example. Sim will always differ from the real plane, many more factors play a major role in this.

Loosing resolution I can imagine although this is strongly dependant on the quality of the joystick card in combination with the effective range of the potmeter which is determined by the transmission ratio. So, In practise there can be well designed for a smaller yoke deflection and consequently there need not to be a resolution loss imo.

Loosing mechanical sensitivity is another story. Imo you are gaining sensitivity with a smaller yoke deflection i.e after proper calibration the variation in output increases with a smaller deflection. So, to overcome a too high sensitivity in a flight sim using a yoke with a deflection of lets say plus/minus 45 degrees, the FSUIPC S-curve slope has to be changed, i.e. sensitivity is relatively low in the beginning and high in the end. Thanks to Peter Dowson the disadvantage of a smaller yoke deflection can be overcome.

[Sudden81]

Of course you can always change the s-curve but the interesting thing IMO is how far you can turn the control wheel in a real plan. It is hard to get that fact if you down't know how it is.


   

[archen]

As Sudden already told you. Even if full deflection is not used very much in real world you will be loosing resolution and sensitivity if not using the full travel. If 45 degrees equal with full deflection, then 22,5 degrees would equal with 50% deflection. In the real plane 22,5 degrees would equal with 25% deflection. In the end you will have to turn the wheel half as much as in the real plane to get the same deflection.


How much this really affect in the end I don't know. Just a theoretical example. Sim will always differ from the real plane, many more factors play a major role in this.

Loosing resolution I can imagine although this is strongly dependant on the quality of the joystick card in combination with the effective range of the potmeter which is determined by the transmission ratio. So, In practise there can be well designed for a smaller yoke deflection and consequently there need not to be a resolution loss imo.

Loosing mechanical sensitivity is another story. Imo you are gaining sensitivity with a smaller yoke deflection i.e after proper calibration the variation in output increases with a smaller deflection. So, to overcome a too high sensitivity in a flight sim using a yoke with a deflection of lets say plus/minus 45 degrees, the FSUIPC S-curve slope has to be changed.

Hi Edward,
You are correct. Resolution was the wrong word to use..  What I meant was sensitivity.. A small movement will result in more deflecting in relation to a 90 degree setup but as you mentioned this can also be corrected in Fsuipc calibration.

Regards,
Anders

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[mickc]

I guess it comes down to how similar you want it to be compared to the real aircraft, after all isn't that what we are all "simulating" ?

Its not uncommon to use up to 60 degrees of travel each way to keep the 737 level during a gusty final approach, so depending on your flight model, too much sensitivity can lead to over-correction.

I also tend not to use FSUIPC curve/slopes for the ailerons, as there is no control surface acceleration or "null zones"on the 737.

One of the biggest things you will notice if you every fly the real thing is just how much you need to move they yoke to get the aircraft to respond compared to smaller aircraft, especially at lower airspeeds.

[sluyt050]

I guess it comes down to how similar you want it to be compared to the real aircraft, after all isn't that what we are all "simulating" ?

Its not uncommon to use up to 60 degrees of travel each way to keep the 737 level during a gusty final approach, so depending on your flight model, too much sensitivity can lead to over-correction.

I also tend not to use FSUIPC curve/slopes for the ailerons, as there is no control surface acceleration or "null zones"on the 737.

One of the biggest things you will notice if you every fly the real thing is just how much you need to move they yoke to get the aircraft to respond compared to smaller aircraft, especially at lower airspeeds.

I agree mick it would be most realistic to have a realistic deflection. Unfortunately, I have about + - 50 deg.
What I don't quite get is your remark as there is no control surface acceleration or "null zones"on the 737..
Imo the advantage of using S-curve correction is larger than the disadvantage (is there any?).
Could you elaborate on the disadvantage as you see it?

[archen]

When using the S-curve you will get some acceleration. When not using S-curve in calibration deflection is parallell to wheel input. When using S-curve, deflection is lower the closer center you are, the more you turn the wheel, the more deflection per wheel input degree you add. In example:

When turning the wheel 10 degrees you get 15% deflection. 20 degrees 40% deflection. 40 degrees 90% deflection 45 degrees 100% deflection.

When turning the wheel without S-curve you get a linear deflection output the whole travel.

[mickc]

I agree mick it would be most realistic to have a realistic deflection. Unfortunately, I have about + - 50 deg.
What I don't quite get is your remark as there is no control surface acceleration or "null zones"on the 737..
Imo the advantage of using S-curve correction is larger than the disadvantage (is there any?).
Could you elaborate on the disadvantage as you see it?

I mean that the aileron operation on the real aircraft is 1:1,  i.e.  you move the control wheel 70% and the ailerons move 70%  there is no change in the relationship of the control wheel travel to the aileron travel. - where on say an Airbus the ailerons move at a greater rate the further the sidestick is pushed.

In my opinion, FSUIPC curves are better suited to joysticks when you only have +/- 30 degrees of movement so that you have you have better control closer to the centre of travel, or for setups that may have non-linear pot mechanisms etc.

There is no specific disadvantage of using them, again, its a personal preference 


EDIT:  Archen said it better and quicker while I was typing my post 

[sluyt050]

May be I am too fast but can we conclude that to overcome limited yoke deflection the use of S-curve correction will help to get a more realistic yoke sensitivity, particularly around the center? The magnitude of this correction stays a matter of personal preference.

I recently read somewhere that a captain tested a non-certified flight sim and in the end his remarks were that the yoke roll movement was too sensitive and the forces too low as compared to the real thing.

[archen]

Yes I believe you get a better feel if you lower the sensitivity near Centre but you should be aware of the the higher sensitivity on the higher deflections but maybe you don't use that much of input so it might be worth to lower sensitivity for near-center-inputs.

Try different curves to find one you like.. I guess it's a matter of how you want it to feel.

Anders

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[Maurice]

Does all this really, really matter in a home sim? Unless you are a real 737 pilot, you really have no idea how a real yoke feels especially since you most likely do not have force feedback that varies with how fast you are going when you use the ailerons or rudders.

So this discussion is pretty much academic since none of you will be able to achieve an accurate reproduction of a real aircraft control forces unless you build it to CAE standards.

In the end, each of you will adjust the curve (or not) to your preferred feel and it will very likely bear little resemblance to how the real airplane reacts, so why worry about it? It will be as real as it gets to your eyes only and that is all that really matters.

A long time ago, I had a chance to fly a 747 CAE simulator and later a 737 CAE simulator. In both cases, I was very surprised by how hard it was to turn the yokes and there is no way I wanted that in my own sim so I adjusted the leverage to suit my taste and did not care how my flying guests felt about it. This was my sim built the way I liked it. 

Maurice

[Sudden81]

And whit that statement where does it stop. Blue backlight, black panels, Airbus yoke because it is better feeling, 777 gear handle. It is the small things that makes the difference. For example I have flown the full motion sim in Lelystad whit Flyengravity panels and backlight and you instantly notice that the real backlight is better and that FDS is far closer to the real thing when it comes to panels.

It is only my opinion but if I I could get as close to the real plan as possible I am happy

White that sad If someone asks how mush the real controls travel he probably is interested in that, not in how far someone's control wheel turns in there home cockpit.

Always aim hi and get as close as possible whit out breaking the budget.

But everyone is absolutely free to do as they which of course.

By the way I have also bin to a Level-D CAE sim.

Best regards Jacob

[sluyt050]

We, being serious flight simmers like to be as close to the real thing as possible. The real thing is the reference. So, a lot of discussions are just going about that. But there is no penalty if one likes to deviate from that for various reasons. Whatever is the outcome, the longing for the reference remains. That's probably the reason a sim is never finished, a topic we all know well, which is good. Main part of the fun is the way and the creative process to get it as real as possible. I have to stop here before getting really philosophical.