How To Do These Manoeuvres in DCS?

[Punkmonkey22]

See vid from 3:35 - 3:55. Every time I try and pull hard "slides" through the sky at low speed like this I just get lots of warnings and a slow turn. 

What is the method for forcing the back of the plane around like that, and is it even modelled in DCS? I know this is a CF-18, not a Charlie, but given it's based on the older A model I would have thought it was possible.

 

[Tenkom]

Hmm.. I haveb't done it but I feel like that should be quite possible to do in DCS. With some practice mind you.

[Hulkbust44]

Even with the latest AoA FM changes, we still seem to be lacking roll/ yaw rate and authority when trying to do loaded rolls. Specifically above 22 alpha as I recall.

Sent from my moto g stylus 5G (2022) using Tapatalk

[TheFreshPrince]

I have a feeling that it's a general problem in DCS where the planes are not as responsive and maneuverable at slow speeds as they should be. They always feel a bit slow in response and stiff, so you can't really reproduce airshows. SU27 and MIG29 are other examples. 

[Czar66]

This was a while back and it is possible to do slower and better. It was really sloppy too on my part.

Yaw and Roll to the same direction while pulling on the stick. Mess around with the F3 view zoomed in on a safe altitude and play with the plane like you're controlling a RC plane and you'll get the point.

[TheFreshPrince]

vor 17 Stunden schrieb Czar66:

This was a while back and it is possible to do slower and better. It was really sloppy too on my part.

Yaw and Roll to the same direction while pulling on the stick. Mess around with the F3 view zoomed in on a safe altitude and play with the plane like you're controlling a RC plane and you'll get the point.

Yeah but this doesn't look like in the video at all... In DCS the plane also becomes extremely unstable after such maneuvers, which you cannot see IRL. 

Edited July 27, 2024 by TheFreshPrince

[Czar66]

13 minutes ago, TheFreshPrince said:

Yeah but this doesn't look like in the video at all... In DCS the plane also becomes extremely unstable after such maneuvers, which you cannot see IRL. 

 

I didn't capture that to match the video. That was years ago and before the FCS update. I showed the rear end being pushed around like OP mentioned.

It is possible to do much close to what the video shows. There is nothing "extremely unstable" phenomenon if you pull high AoA and maneuvers in the 18 if you know how to handle the plane.

Mushy? Yes.

Extremely unstable? Exaggerating.

Go to 5k to 10k ft -> F3 camera -> zoom in (rCtrl + *) -> play with it.

Edited July 27, 2024 by Czar66

[Punkmonkey22]

On 7/26/2024 at 11:02 PM, Czar66 said:

This was a while back and it is possible to do slower and better. It was really sloppy too on my part.

Yaw and Roll to the same direction while pulling on the stick. Mess around with the F3 view zoomed in on a safe altitude and play with the plane like you're controlling a RC plane and you'll get the point.

Thank you for showing similar can be done. I think I need to play with the throttle differently when I try it, sounds like they push max throttle as they start the slide. All timing I guess

[Figaro9]

What a great display, thx for sharing!
I tried that part you mentioned today in dcs based on swiss and canadian display programs & manuals.

Square loop and rudder roll 325 KCAS, 

 

1. 500ft gnd, 325kts, max ab, max G pull to the vertical. 
2. unload for a vertical extension to 3500 feet AGL. 
3. pull 25° AOA to inverted flight (maximum of 10 seconds).
4. VV ~10 above horizon, airspeed 135-200 KCAS, pull 25-30o AOA 90° nose down
5. At a minimum altitude of 2500 feet AGL or 300 KCAS (whichever occurs first) pull 25° AOA to level flight no lower than 300 feet AGL
6. turn 40° away (left) from display axes. 
7. pull to 45° nose up 25°aoa Rudder Roll (full rudder right, aileron neutral, elevator for 25°aoa), minimum airspeed 180 KCAS.

 

can't say if the rudder roll in the 18 is done by rudder only or with aileron too. I tried both, but to capture and hold 25° aoa with rudder only is far easier.

 

I did one demo close to the program above and one a bit crispier..

airshow 28-7-24 crispy.trk airshow 28-7-24.trk

Edited July 28, 2024 by Figaro9

[DmitriKozlowsky]

On 7/24/2024 at 10:58 AM, Punkmonkey22 said:

See vid from 3:35 - 3:55. Every time I try and pull hard "slides" through the sky at low speed like this I just get lots of warnings and a slow turn. 

What is the method for forcing the back of the plane around like that, and is it even modelled in DCS? I know this is a CF-18, not a Charlie, but given it's based on the older A model I would have thought it was possible.

 

You have to disable AOA limiter/ flight envelope protection on left side console near throttle. Turn it back ON after maneuver. However your stick and rudder skills have to spot on or you will depart the aircraft. Probably into spin.

[MeatServo]

It's doable. You risk departing if you do more than 3 much like the real thing.

CF18 Demo Manual is unclass in the public domain. Maneuvers described generally work as they should. 25 degree AOA stick, roll, and rudder. I started mine out a bit messy this run as I haven't practiced them in a while, but second 360 worked out.

https://www.faa.gov/sites/faa.gov/files/about/initiatives/airshow/CF-18_Fighter_Demonstration_Manual.pdf

Edited August 12, 2024 by MeatServo
Clarification

[DummyCatz]

On 7/28/2024 at 10:53 PM, Figaro9 said:

can't say if the rudder roll in the 18 is done by rudder only or with aileron too. I tried both, but to capture and hold 25° aoa with rudder only is far easier.

Pedal and lateral stick provide similar roll responses at around or above 25° AOA IIRC, due to the two-way interconnect between the rudder and ailerons. So you're fine with either the aileron or the rudder.

BTW if above 35° AOA, the Pirouette logic will be activated by using combined pedal and lateral stick inputs. But it seems that the AOA is not that high in the demo video.

[Figaro9]

On 8/12/2024 at 5:23 AM, DummyCatz said:

Pedal and lateral stick provide similar roll responses at around or above 25° AOA IIRC, due to the two-way interconnect between the rudder and ailerons. So you're fine with either the aileron or the rudder.

BTW if above 35° AOA, the Pirouette logic will be activated by using combined pedal and lateral stick inputs. But it seems that the AOA is not that high in the demo video.

I agree. The pilot is hardly pulling 34° aoa in the video. According to the manuals and programs provided above, 25° AOA is used to rudder roll. Most likely cause from 25° to 35°AOA the roll rate decreases quite a bit…

Btw, the pirouette logic is already induced at AOA>25° and KCAS<210kts if full rudder and full lateral stick in the same direction are paired.

Also agree, > 25° AOA, fcs commands similar control surface deflections for rudder and lateral stick inputs. 

Digging a bit deeper, looking at the ‚roll performance enhancement at high aoa’ graph, it seems that at 25° AOA the roll is not only crisper than at higher alpha. Combining lateral stick and rudder does not improve the roll rate here (it doesn‘t hurt either), while it significantly does at alpha > 30°.

Conclusion: It looks like rudder only rudder roll at 25 Alpha does the crispest job. Adding lateral stick does neither hurt nor improve the roll rate here.

Edited August 13, 2024 by Figaro9

[DummyCatz]

2 hours ago, Figaro9 said:

 

I agree. The pilot is hardly pulling 34° aoa in the video. According to the manuals and programs provided above, 25° AOA is used to rudder roll. Most likely cause from 25° to 35°AOA the roll rate decreases quite a bit…

Btw, the pirouette logic is already induced at AOA>25° and KCAS<210kts if full rudder and full lateral stick in the same direction are paired.

Also agree, > 25° AOA, fcs commands similar control surface deflections for rudder and lateral stick inputs. 

Digging a bit deeper, looking at the ‚roll performance enhancement at high aoa’ graph, it seems that at 25° AOA the roll is not only crisper than at higher alpha. Combining lateral stick and rudder does not improve the roll rate here (it doesn‘t hurt either), while it significantly does at alpha > 30°.

Conclusion: It looks like rudder only rudder turn at 25 Alpha does the crispest job. Adding lateral stick does neither hurt nor improve the roll rate here.

Yes you were correct about the pirouette logic activation criteria, my memory fails me.

The current problem is that, the logic may not be correctly implemented in DCS. IRL it introduces a bias signal (sum of lateral stick and rudder that is greater than an equivalent of 3 inches*) into the sideslip feedback path, creating what is essentially a sideslip command. The sideslip feedback directly feeds to the aileron and differential stabilators, regulating the amount of adverse yaw and hence sideslip generated by the aircraft.

But as elaborated in another post of mine, there's a bug in the sideslip feedback path, that feeds erroneously to the rudder. The aerodynamic implementation of adverse yaw is also questionable. Let's see how it'll get sorted out.

As a result, the FCS in-game will use more rudders than expected. But yeah, it's only a problem when AOA is greater than 25 deg.

 

*ref https://trace.tennessee.edu/utk_gradthes/2372

Edited August 13, 2024 by DummyCatz

[MeatServo]

Here, I did a better one after practicing a bit.

[fagulha]

On 7/30/2024 at 6:24 AM, DmitriKozlowsky said:

You have to disable AOA limiter/ flight envelope protection on left side console near throttle. Turn it back ON after maneuver. However your stick and rudder skills have to spot on or you will depart the aircraft. Probably into spin.

Are you refering to GAIN ORIDE switch right beside the FCS Reset?

[Talvid]

InDCS I can only do an exaggerated barrell roll like that when I'm fast and straight and level, never right after a slow speed high AOA turn.  

[TheFreshPrince]

What I notice from the video and GIFs in this thread is that you have to blast full AB in DCS to do any maneuver, especially the slow speed ones and you're still on the edge of falling out of the sky. While in the video it looks much more like mil power, sometimes even less (can't see any orange flames) and it still moves effortless. Something aint right there. 

[BuzzU]

I used to fly in RC Pattern Competition. Precision Aerobatics.

We called what you're doing a Snap Roll.

Edited November 30, 2024 by BuzzU