News:

Precision Simulator update 10.175 (29 May 2024) is now available.
Navburo update 13 (23 November 2022) is now available.
NG FMC and More is released.

Main Menu

Pitch rate slower than real B744.

Started by Daehee, Wed, 25 Oct 2017 16:28

Hardy Heinlin

A note in advance:

I will not change the mathematical link between hardware yoke and PSX yoke. This has to be and will remain in sync 100%, at all yoke positions.

I only make modifications in the aerodynamics model. It's about the pitch effect model of the surface angles of the four elevators at the aircraft tail. It's not about USB or computer network.


Cheers,

|-|ardy


Daehee

Quote from: Hardy Heinlin on Sat, 28 Oct 2017 13:29
A note in advance:

I will not change the mathematical link between hardware yoke and PSX yoke. This has to be and will remain in sync 100%, at all yoke positions.

I only make modifications in the aerodynamics model. It's about the pitch effect model of the surface angles of the four elevators at the aircraft tail. It's not about USB or computer network.


Cheers,

|-|ardy
Hardy,
Let me ask you one thing..About aerodynamics, Is it different by aircraft model or not? I always use for testing with Korean Air model inside PSX.

Daehee Kim

cagarini

Quote from: Hardy Heinlin on Sat, 28 Oct 2017 13:29


I only make modifications in the aerodynamics model. It's about the pitch effect model of the surface angles of the four elevators at the aircraft tail. It's not about USB or computer network.


Cheers,

|-|ardy

That's a sound approach, but of course I believe it'll give you some work.
"Messing" around with the pitching moments, pitch rate and associated stability derivatives, and probably also hinge forces if these are being computed, can result in impacts on other flight dynamics features...

Let's hope for the best in the end results...




Hardy Heinlin

Good question, Daehee Kim. (By the way, you need not quote my post if you reply directly.)

The airline names will not change the aerodynamics.

Only the drag and FF correction factors on Instructor > Model > Airframe will change the aerodynamic drag and engine fuel flow. They are set to 0.0 in most model files. These are not airline specific either, but individual from aircraft to aircraft within the same airline fleet.


Regards,

|-|ardy

United744

If anything needs adjustment, it is maximum deflection, as the aircraft doesn't seem to pitch fast enough. Full up elevator at 300 kts would be pretty wild I'd imagine. Reading accident/incident reports is always interesting for pitch/roll rates sustained.

Currently the aircraft just doesn't seem to pitch fast enough, considering it should be pulling in excess of +3 g.

John H Watson

QuoteFull up elevator at 300 kts would be pretty wild I'd imagine.

.... assuming the pilot is strong enough to pull it fully up. During ground tests with simulated airspeeds of 204kts, breakout force is only 8.6lbs, but the force to pull the stick fully aft is 72~106lbs.

United744

That's an interesting point.

@Hardy: with the current maximum deflection, what is the force required to deflect it?

Jeroen Hoppenbrouwers

Getting the lack of feel feedback worked into the pitch input has always been a pain. I know Hardy has a few things different than ideal exactly because of this lack of 50 kg force feedback. A compromise is probably inevitable.


Hoppie

United744

Maybe I'm thinking of another sim, but doesn't PSX restrict control deflection based on speed? i.e. Max attainable elevator at 350 kts is less than at 200 kts, to simulate this effect?

Aileron trim for example requires "assistance" when trimming.

Hardy Heinlin

You mean yoke deflection limited by airspeed? I would never do this. Why not? Because the real 747 doesn't do this.

"Aileron trim requires assistance" is something else. This is an effect on the real deck indeed.

In PSX and on the real 747, the deflection angles of the rudder surfaces (not pedals) are limited by airspeed, and the outer aileron surfaces (not yokes) are locked out at certain airspeeds. Stabilizer motion rate is also airspeed dependent. These are no sim tricks but real 747 features.



Quote from: United744 on Sun, 29 Oct 2017 12:50
@Hardy: with the current maximum deflection, what is the force required to deflect it?

If you use the arrow keys on an Apple keyboard, I would say 10 gram. Mouse: 30 gram. Logitech joystick: 500 gram. Thrustmaster Warthog: 5 kilogram. 747 yoke: 40 kilogram.

Hardy Heinlin

Quote from: Britjet on Fri, 27 Oct 2017 17:06
I don't see a problem with small inputs on approach. It looks ok to me.
I was more thinking of large upset recovery rate..
As Hardy says, it depends on a lot of factors..

Peter.

I must admit I too haven't been happy with the nose down rate. But since nobody complained in the last few years, I thought it was a good compromise for everyone (opinions always vary, also among 747 pilots).

I would suggest to increase the nose down rate so much that it's the same as the nose up rate. Do you guys really want to increase the nose up rate as well?


Regards,

|-|ardy

Daehee

Hello,

I recorded some movie with my friend.

Please review and write your opinion.

1. Real-word B744 training sim from CAE(Level-D).. flied by real world B744/B748i Captain.
Unfortunately, we can't see yoke position, because he recorded during his training. But, he tested and check response speed. CAE is more faster(0.5 sec) than PSX.
https://youtu.be/P4rE86Pfils

2. PSX .. flied by real world B744/B748i Captain.
https://youtu.be/nPOn1EattrM

3. PSX .. flied by me.
I don't have any real world experience.. only have PMDG. PSX controlling is difficult than PMDG.
https://youtu.be/GcoKDgB431k

4. Steep turn.. flied by real world B744/B748i Captain.
Just for controlling test.
https://youtu.be/oQjV1y5gSwM

Our opinion is more faster(around 0.5 sec for pitch response) than now, that is best for pitch response rate..

What does mean both 'Gary Oliver' and 'Chris Kilroy' said? Is that meaning of pitch rate by some tweak?
>>Gary said : My joystick program in our Sim inputs 1.35x the actual deflection into PSX...
>>Chris said : I, like Gary, also have the pitch axis in my sim set to about 1.33x based on the feedback...


Best Regards.
Daehee Kim.

Hardy Heinlin

#32
Hello Daehee Kim,

thank you for the videos. Regrettably, the number "0.5" alone without a target rate makes no sense to me. There is no delay in PSX that would keep the rate at 0 for a certain time. There is an inertia with a gradual acceleration from 0 to the target rate. Anyway, PSX 10.7 will have a greater nose down rate (effective for deflections beyond 50%). Recovery from high nose up attitudes will be a lot easier. Flight control in the normal mid range will be as easy as before (at least in my opinion; also, it agrees with what I experienced in Lufthansa sims).

I just learned one new thing though. The trend vector on the ND in that CAE sim also works on the ground, and even below 80 kt groundspeed. Is that an airline option? Do you know if this also works at taxi speed?


Thanks,

|-|ardy


What kind of test is this? https://youtu.be/vPJnYPqnlkw
I see the yoke icon in PSX moving up and down just a little bit. Is that full deflection on your Saitek yoke? When your Saitek is at max deflection, the yoke in PSX should be at max as well. If it isn't, the USB calibration is not correct and, of course, manual flying will not be easy.

United744

QuoteIf you use the arrow keys on an Apple keyboard, I would say 10 gram. Mouse: 30 gram. Logitech joystick: 500 gram. Thrustmaster Warthog: 5 kilogram. 747 yoke: 40 kilogram.

hehe - not quite what I meant.

What are the aerodynamic loads as simulated in PSX on the elevator at maximum deflection, at say 250 kts? You obviously know what the deflection angle is, so can compute this value?

Another way to look at it - how much pitch authority do we get?

Hardy Heinlin

The load force and hydraulic anti-force is irrelevant. The elevator has always full authority in relation to the yoke position. The spoilers, however, cannot fully extent at very high speeds. The model just uses an empirical function of airspeed, not indirectly via force and anti-force which would lead to the same result anyway. That would be like modelling fuel molecules to calculate fuel temperature :-)

United744

Well that's interesting then. If we do indeed have full elevator deflection available, then why the apparent discrepancy?

Hardy Heinlin

Because the opinions of PSX users vary, and I always try to make everyone happy. So I have to make changes in my model. Whenever I change something from status A to status B, there will be a discrepancy between A and B. In version 10.7 we will get C ...

It's not about elevator deflection per se. It's about its effects in the aerodynamics model.

United744


Britjet

Hardy,

A video on its way to you shortly. It may help but I realise all the aforesaid..
Peter

United744

Does any aircraft have as much nose down authority as nose up?? I thought due to lift, the pitch up authority was always greater, ignoring positive and negative g limits (negative g always being more limiting).