Can no longer trim down after brakes, slow speed

OK, then it must be a limitation of my HOTAS :( ... don't worry, I will look for a workaround, perhaps a Macro that presses the key 17 times :)

Is it possible that your HOTAS binding is also a modifier? Because that would definitely affect your ability to press different keys.

Hola Eduardo.

First of all, sorry that you have troubles programming speed brake in your HOTAS, but I'm sure you'll find a way since Cougar software is a very powerful tool.

I confirm that the switch in the real airplane behaves so, you have to press and hold it to get to a full deflection, or deploy it to intermediate positions, that is why we implemented it that way, and it should be like this in any aircraft or at least most of them.

Also, as Kontiuka says, I would delete the toggle option, at least until we find a solution to it, or perhaps indefinetely, if we don't find an easy solution or if we want to keep it at full realism.

Or you could get rid of speedbrake multi-crew code if that's the link. Not even in the L-39 is speedbrake multi-crew working fully well.

Hola Eduardo.

First of all, sorry that you have troubles programming speed brake in your HOTAS, but I'm sure you'll find a way since Cougar software is a very powerful tool.

 

Yes, dont worry, I will try different alternatives ... and once I have one that works well, I will then update my profiles: https://www.digitalcombatsimulator.com/en/files/?set_filter=Y&arrFilter_pf%5Bfiletype%5D=70&arrFilter_pf%5Bgameversion%5D=&arrFilter_pf%5Bfilelang%5D=&arrFilter_pf%5Baircraft%5D=151&arrFilter_DATE_CREATE_1_DAYS_TO_BACK=&CREATED_BY=&sort_by_order=TIMESTAMP_X_DESC&set_filter=Filter

 

I confirm that the switch in the real airplane behaves so, you have to press and hold it to get to a full deflection, or deploy it to intermediate positions, that is why we implemented it that way, and it should be like this in any aircraft or at least most of them.

 

I see .. ok then, I will work on this a bit more and hopefully will have it sorted out soon.

Best regards,

 

Eduardo

Or you could get rid of speedbrake multi-crew code if that's the link. Not even in the L-39 is speedbrake multi-crew working fully well.

Hi Sirius.

I would rather prefer deleting the toggle function than getting rid of speed brake implementation in rear cockpit in multiplayer. BTW, could someone test it online in rear cockpit and swapping to front cockpit as well? We tested it internally but would need a more thorough test. Thank you :)

On a related topic, I've been trying to figure out why the air brake causes a pitch up moment. It just seems intuitive to me that a backwards facing force on the air brake would cause a pitch down moment. I must be missing something. Can you give a brief explanation of what forces are acting on the aircraft to make it pitch up? Does the brake drive the air into the bottom of the fuselage causing an upwards force?

It all depends on how much aft is the center of mass of the aircraft. Let's consider a C-101 flying in level flight. If the center of mass of the aircraft is far enough to the rear, the vertical component of the aerodynamic pressure created by the airbrake surface will create a pitch up moment higher than the pitch down moment created by the horizontal component of the aerodynamic pressure, since the arm of the first will be longer than the later. The center of mass is rather near to the center of the air brake, so it's not easy to see why this effect is really happening in the direction it does. But this is how it behaves, it is written that way in the manual, it is confirmed by real pilots and, more importantly, it is the real aircraft aerodynamic data that we got.

It all depends on how much aft is the center of mass of the aircraft. Let's consider a C-101 flying in level flight. If the center of mass of the aircraft is far enough to the rear, the vertical component of the aerodynamic pressure created by the airbrake surface will create a pitch up moment higher than the pitch down moment created by the horizontal component of the aerodynamic pressure, since the arm of the first will be longer than the later. The center of mass is rather near to the center of the air brake, so it's not easy to see why this effect is really happening in the direction it does. But this is how it behaves, it is written that way in the manual, it is confirmed by real pilots and, more importantly, it is the real aircraft aerodynamic data that we got.

Makes sense. Thanks for the explanation.

On a related topic, I've been trying to figure out why the air brake causes a pitch up moment. It just seems intuitive to me that a backwards facing force on the air brake would cause a pitch down moment.

 

Hello,

 

About this subject, it seems that the flight model is still being tweaked a bit, as now rather than a pitch up moment, we are having a gradual pitch down, as seen on this video:

 

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I first trim the aircraft for level flight, then open the airbrake .. I'm now using momentary joystick buttons, rather than keyboard key-presses) that I hold until the airbrake is fully extended or fully closed. You can see that the aircraft now pitches gradually towards a nose down attitude.

 

What is strange, is that this time I saw no evidence of automatic trim on the trim visor .. as the manual of the real plane says, there should be an automatic trim applied that should keep the plane more or less level:

 

 

On spanish only, sorry, dont know if CASA ever made an english manual.

 

Regarding my HOTAS, after a lot of testing I came to the conclusion that commanding the airbrake trough key presses gives a very different effect than commanding it trough the standard joystick interface ... so, in order to get my HOTAS to work better, I chose to bypass the keyboard emulation of the Thrustmaster Cougar and assigned two buttons to the standard DirectX buttons of DCS, like this:

 

 

I will now update my two profiles, for EB and CC, as the ones currently on ED's User's Files have a very bad actuation of the airbrake that can lead even to the loss of pitch up authority on the pilot's stick.

 

Best regards,

 

 

Eduardo

Edited February 7, 2019 by Rudel_chw

Hi Eduardo, sorry to dismantle your arguments :), but we didn't change anything in the trim coding or anything related to it, except deleting the option to use Air Brake Toggle. I also confirm that there is no difference in trim speed using keyboard or joystick buttons, and that must be related to your Thrustmaster Cougar as you say. Trim speed in our simulation is according to real aircraft.

Good that you managed to make a macro for your Cougar, great job! :thumbup:

If you want to try out the pure aerodynamic effect of the air brake, without its automatic pitch trim function linked to the air brake switch, you can open the guard of the Emergency Elevator Pitch Trim Switches. In this case, you will notice that extending the speed brake will create a pitch up moment that you will have to compensate with the control stick, or the emergency pitch trim switches.

Hi Eduardo, sorry to dismantle your arguments :), but we didn't change anything in the trim coding or anything related to it, except deleting the option to use Air Brake Toggle.

 

It's so strange, as previously the airbrake extension caused a pitch up, while now it causes a (more gradual) pitch down.

 

I also confirm that there is no difference in trim speed using keyboard or joystick buttons, and that must be related to your Thrustmaster Cougar as you say. Trim speed in our simulation is according to real aircraft.

 

I've stopped using the keyboard for the speedbrake operation, as at least on my case I couldnt get it to work. The manual of the real aircraft says that there shouldnt be a change on pitch, as the system compensates for it .. but I dont experience that on the sim.

 

Good that you managed to make a macro for your Cougar, great job! :thumbup:

 

:) It's not really a macro: The Cougar's native mode of operation is like it is a programmable keyboard ... I press a button, and the device produces a keypress. DCS never gets to see the Cougar as a joystick, it is misled into thinking that I'm pressing keys on the keyboard.

 

As the Sim was behaving different with key commands than with joystick button presses, I used a facility that the Cougar has in order to pass the value of Buttons DX24 and DX25 directly to the Sim .. the sim (for those two buttons only) can see the joystick buttons being pressed, instead of receiving the equivalent keyboard keypresses.

 

If you want to try out the pure aerodynamic effect of the air brake, without its automatic pitch trim function linked to the air brake switch, you can open the guard of the Emergency Elevator Pitch Trim Switches. In this case, you will notice that extending the speed brake will create a pitch up moment that you will have to compensate with the control stick, or the emergency pitch trim switches.

 

Thanks a lot for the info, will give it a try this weekend :)

Best regards and thanks for the patience.

 

 

Eduardo

If you want to try out the pure aerodynamic effect of the air brake, without its automatic pitch trim function linked to the air brake switch, you can open the guard of the Emergency Elevator Pitch Trim Switches. In this case, you will notice that extending the speed brake will create a pitch up moment that you will have to compensate with the control stick, or the emergency pitch trim switches.

confirmed. when I open the guard, the air brake causes a pitch up moment.

 

I did find a small bug while testing this though.:P

 

If you open the guard and use the emergency trim nose down for example and close the guard without returning the emergency trim switch to its centre position, the next time you open the guard, the nose will continue to trim down. Same for emergency trim up. All is fine if you remember to return the switch to its centre position.

confirmed. when I open the guard, the air brake causes a pitch up moment.

 

I did find a small bug while testing this though.:P

 

If you open the guard and use the emergency trim nose down for example and close the guard without returning the emergency trim switch to its centre position, the next time you open the guard, the nose will continue to trim down. Same for emergency trim up. All is fine if you remember to return the switch to its centre position.

The switch should return to neutral. Will check that.

It's so strange, as previously the airbrake extension caused a pitch up, while now it causes a (more gradual) pitch down.

That's not right. The airbrake behaves exactly as before, it makes the a/c pitch up when extending it. When using the "autotrim function" (emergency guard closed for example) the airplane will stay aprox. at the same pitch attitude if you are at slow speed. It you are flying at high speed, above 300 kts, like the manual says, the trim speed is not able to compensate the airbrake pitch moment and the aircraft will pitch up a bit. If you are flying slow, the trim speed is able to compensate the airbrake effect and therefore there's almost no pitch change. And this demonstrates, once again as other kind of tests show, that our flight model is correct, also in this aspect of the flight.

 

I've stopped using the keyboard for the speedbrake operation, as at least on my case I couldnt get it to work.

It must be on your case as you say, because it works exactly the same as using a joystick button and as in the real aircraft.

The manual of the real aircraft says that there shouldnt be a change on pitch, as the system compensates for it .. but I dont experience that on the sim.

The simulation reflects exactly the behavior of the real aircraft and what's described in the manual. Sorry, but you seem to be a bit confused with this. Read above :)

:) It's not really a macro: The Cougar's native mode of operation is like it is a programmable keyboard …

I know perfectly how to program the Cougar, I had one for many years since it arrived to the market and I still use it, I've made many advanced profiles for it, though it's a long time since I don't program it. BTW I have it with the FSSB R2 mod from Real Simulator :)

Thanks a lot for the info, will give it a try this weekend :)

Best regards and thanks for the patience.

 

Eduardo

You are welcome. There seems to be some confusion with how the airbrake and trim interaction works. I tried to explain it several times but maybe I'll have to write again a more thorough explanation of the system.

The switch should return to neutral. Will check that.

It appears visually to return to neutral but doesn't act so.

It appears visually to return to neutral but doesn't act so.

Yes, saw the problem. Thanks for the report. Solution pending.

Hey Vibora,

 

The C101 (at least the CC) constantly adds nose up or nose down trim as long as the speed brake button is held in either the retract or extend position, regardless of the position of the speed brake. This seems really dangerous as it could result in large shifts in the pitch trim, particularly before takeoff. I know that checking trim is part of the takeoff checklist, but it just feels very unlikely that an aircraft manufacturer would leave this dangerous "feature" in a flight-worthy training aircraft. Is this really in the real C101?

 

Shouldn't the trim adjustment halt once the speed brake reaches a fully open or closed position?

 

Appreciate all your fine work, looking forward to getting educated on the C101!

Hi EinsteinEP. It's simulated as the real aircraft. That's how it works in the real aircraft. Try to bind it to a spring-loaded switch (like the real one) of your HOTAS if you can.

That's how it works in the real aircraft.

 

Thanks for the confirmation! Seems like a really poor aircraft design choice.