[SOLVED] Elevator madness.

[Sopwith]

Lovely job, thanks. 

If I pull the elevators up, at about 50% of my set pitch control (pro flight yoke) the elevator goes to the full down position and if i maintain the full elevator up input the elevator moves rapidly up and down. 

Try some mild jetstream aerobatics and you will discover what I am talking about.

It also occurs on finals if you get to slow. Easing back on the elevator suddenly results in pitch down.  

 

Edited December 17, 2012 by Japo32

[Sopwith]

Both 9 and 10, only happens in flight. 

[Cameron]

What happens if you make these adjustments with the mouse and not your hardware setup?

 

I'm curious to know the result of that first before we continue to troubleshoot this with you.

[Japo32]

1. The finals slow. The real time controls the BETA stage of the propeller with the throttle It is defined in plane maker that below a 0.02 ratio of the full throttle range the plane enters in BETA. That means the plane will loose drastically push.. so you will pitch down as you describe. You don't have to pull fully the joystick.

I put that number (0.02) because coincide with my joystick dent.. so I know when I am reaching it.

It is easy to change it. Go to plane maker.. open the jetstream (of course make a backup copy).. then in Engines menu.. to the left.. there is the "go BETA below this throttle setting". If you set to 0.0 it won't go...but won't be as the real plane. You can put other number to coincide with any mark your hardware throttle has... 

 

2. About the Elevators... I don't understand quite well... 

There is a system in the plane that is the stall warning. When on.. and you have an STALL.. the plane will automatically push forward the joystick to exit automatically the STALL. That means UNTIL the stall is exit, you cannot push it back (you can but the plugin won't let you so it will go back). It is because the stick pusher.

You can still have the STALL light warning system... BUT not the stick pusher.. how? read the manual. Page 16.

 

Thanks!

[cessna729]

Lovely job, thanks. 

If I pull the elevators up, at about 50% of my set pitch control (pro flight yoke) the elevator goes to the full down position and if i maintain the full elevator up input the elevator moves rapidly up and down. 

Try some mild jetstream aerobatics and you will discover what I am talking about.

It also occurs on finals if you get to slow. Easing back on the elevator suddenly results in pitch down.  

Hi sopwith, as Javier suspects you were stalling the aircraft and the stick pusher was going off, if you just press the stall warning lights on the dash you can disarm the stickpusher and just get the stall warning as per my short vid:

p.s. Appologies for the poor quality vid, it's my very first!

cessna729

[Japo32]

good video! if you see it more carefully with the stick pusher the lights are red.. and without them are amber.

[Sopwith]

You are right, its the stick pusher.  Thanks.  

A small point but perhaps this input (stick push) could be slowed down a bit. Its rather violent. I many years ago worked on tridents with a stick push. From neutral to full forward took about 1.5 seconds. It was a progression rather that a flick.

Cheers.

[Japo32]

Ok.. I will take a look at that.

[kerbaugh]

Hi Javier,

 

I'm hardly an expert on stick pushers but I did some research on them and have some thoughts regarding possible issues. If I'm wrong about any assumptions I apologize; I'm not trying to denigrate. You warned us about it in the manual and have given us the ability to turn it off so I’ve got no problem with it and applaud your effort to model a stick pusher.

 

That said, you did provide me one of the funniest flights I’ve ever seen. I tried to stall the plane onto the runway and it proceeded to “dribble” me down the runway. It bounced me halfway down the runway, slamming me hard enough on each bounce to obliterate any real aircraft. It would make a hilarious movie.

 

I have no experience with stick pushers but Sopwith must be correct; no real system would send the plane into negative Gs to get the nose down and no real control column could move in the blink of a computer eye.

 

Second, it is my impression that you have no delay between the stall warning and the stick pusher. Everything I’ve read indicates that the warnings come first and the stick pusher doesn’t activate until the aircraft is well into the stall regime. There should be a difference between the angle of attack at which the stall warning is sounded and angle at which the stick pusher “feels” the need to take over.

 

I’m not certain about my last observation and I’m not sure that the correct behavior can be modeled in a software flight simulator. After a real stick pusher has pushed the stick forward, it is in a new position and plane’s control surfaces are in a new configuration. Naturally your software stick pusher cannot move my hardware joystick and it seems to me that after your stick pusher is done, the elevators return to where they were before the action, which of course results in secondary stalls. (often many of them) In fact the result resembled phugoid oscillations on steroids.

 

You could model the action of the stick shaker by changing the trim, which would prevent the control surfaces from even wanting to return to their original position. On the other hand, forcing the pilot to retrim the plane might be annoying. (and not nearly as entertaining as being bounced down the runway) Also, if it occurred multiple times the trim would eventually reach full nose-down and the plane would likely become unflyable.

 

I apologize but I don’t see a good way to resolve my last point. It would seem to be the same problem you would have when disengaging the autopilot so maybe you’ve already addressed a similar issue. No matter what you decide, Sopwith has a good point. It’s bound to be more palatable if you do it smoothly.

 

Anyway, this is a great plane and I only want help make it better. I confess that I want to know all I can about big planes and their systems but I prefer flying smaller stuff. This plane is the best of both worlds and destined to become a favorite. I’ll bet that more people can say that about your planes than those of any developer in X-Plane. Thank you so much for everything you've done.

--

Gary

[Cameron]

Gary,

 

As Javier said in the post just above yours and in response to the fact that it is suggested there should be a delay, he is already looking into this.

[Japo32]

Yes yes.. as said.. I will investigate about the delay in the stick pusher and soft move.. I think I can be success with this.. I have an idea. But I do not plan work in this right now.. First comes the liveries, then a little vacations. and then I will go back again for some work. Even If there are not big bugs, I would like to concentrate in releases with new stuff to add, that way people only don't see corrections but new stuff...

Anyway.. step by step.

 

Thanks for the support.

[cessna729]

First comes the liveries, then a little vacations. and then I will go back again for some work.

And a very well earned vacation it will be too!

:)

cessna729.

[Intrance]

Just my 2 cents about the stick pusher;

 

It is a pretty violent mechanism. At the first flight of the day you also check stall protection. First left button to test, next right button, then both to activate stick pusher. When testing the stick pusher, you better hold on tightly to the yoke, or it will slam into full down pretty hard. There is no gradual motion in 1,5 or 2 seconds.

[hiddenace]

Yeah personally i think the stick pusher is fine! my issue was with pitch and roll seemed really mushy it felt like i was flying a cessna with a turbo prop. hand flying is near impossible without rolling my airplane Also i have a significant ROLL to the Right. any one else experience it?

[Cameron]

Yeah personally i think the stick pusher is fine! my issue was with pitch and roll seemed really mushy it felt like i was flying a cessna with a turbo prop. hand flying is near impossible without rolling my airplane Also i have a significant ROLL to the Right. any one else experience it?

 

Sounds like engine management and the side effect of torque.

[Japo32]

Yes.. the roll to the right is as said several times because the plane has 2 CCW engines.

I am touching a little the flight dinamics to make them a little bit more heavy in flight.