Spin recovery switch used in displays???and some questions.

[Ala12Rv-watermanpc]

I love the FM's so I spend a lot of time just flying and trying to carry the plane to its limits, of course the hornet is not the exception and having such an amazing low speed flight capability Im having a blast with it...One of the most amazing display videos I have ever saw is this one:

 

 

Among other things because of the camera angle where you can better watch the evolution of the maneuvers...well, watching this display I wonder if that pilot has enabled the "spin recovery" switch to make most of them??, for instance the ones at 22sec and 2:57sec...I have tried to perform these maneuvers multiple times and managed to get very close but not yet there as good and nice as in the video...I know the hornet in the video is not using the pylons (we cant yet do that at FM level, only cosmetic according with bignewy) so maybe the effect of them is critical in order to be able to perform these maneuvers but after messing arround a bit flying with the spin recovery switch enabled I have noticed that obviously the plane lets you make much more aggresive mix commands (pitch+roll) and also rudder allowing me to get closer to what I see in the video so thats why I ask this.

 

Also, pitch authority feels a bit superior when in spin recovery mode which feels much slower when its off...in many hornet display videos, I see at some point the pilot performs an EXTREMELY aggressive pitch pull up, setting the plane 90º over the horizon at a matter of a second...this seems not possible with the spin recovery switch off. Here you have an example of this at 40 sec mark (also note how the plane is almost "hanging" in the air pretty much stopped in both loopings in this amazing display and how in the second one the plane "skids" at extremely slow speed which I think is only possible with the spin recovery swith on):

 

 

Another thing I would want to ask to you guys with knowledge, what exactly the spin recovery swith does to the FCS??

 

Finally, another thing I would like to know if its normal (I guess its just product of being a WiP product) is that I have noticed that when I enable the spin recovery, sometimes the plane makes a sudden and MAINTAINED pitch down for a few seconds, followed by a sudden instant pith up (hands off the stick so not my fault) and I would like to know if you did noticed this also?

 

thanks!

Edited June 14, 2018 by watermanpc

[Alfa]

As for the first question - I don't know, but I doubt it.

 

 

Another thing I would want to ask to you guys with knowledge, what exactly the spin recovery swith does to the FCS??

 

The switch doesn't actually do much itself - in "SPIN RCVY" position it just forces "spin mode" to appear on the DDI and initiates spin recovery mode automatically if/when the right circumstances are met - giving instructions to the pilot where to put the stick.

 

With the switch in the "NORM" position, the FCS will only display "spin mode" on DDIs when the right circumstances are met and give instructions to the pilot where to put the stick - the actual recovery mode is then only activated if the pilot complies.

 

But IIRC in both cases the FCS will only stay in recovery mode if the pilot follows the on-screen instructions - otherwise it will transition back to CAS mode, which is why I don't think you can use spin recovery in the way you suggest.

[uunilenkki]

And spin mode drives the leading edge flaps full down.

[26-J39]

NATOPS:

 

 

2.8.2.6 Spin Recovery System. The spin recovery system, when engaged, puts the flight controls in a spin recovery mode (SRM). This mode, unlike CAS, gives the pilot full aileron, rudder and stabilator authority without any control surface interconnects and all rate and acceleration feedbacks are removed. The leading edge flaps are driven to 33° ±1° down and the trailing edge flaps are driven to 0° ±1°.

Spin recovery system engagement depends on the position of the spin recovery switch.

[probad]

you want the paddle switch to override the g limiter for better instantaneous rates and aoa, not spin recovery lmao

Edited June 14, 2018 by probad

[Ala12Rv-watermanpc]

thanks for all your answers mates!...well, so I guess its not used when performing a display though I find not possible to achieve the kind of authority showed in the video otherwise...maybe the pylons are the key here...

 

Thanks also for pointing out what the switch exactly does :thumbup:

 

About the pedal turn, yeah its one of the maneuvers I would like to do...as of now, I got really close by starting the pull at about 330knts then stopping at 90º and then pulling hard again at about 220knots...however in the video the hornet slides with much more energy and more aggresively than what I could achieve...If I try with more speed then the plane follow the flight path very tight and no slide take place...slower doesnt give me enough speed to achieve the last part of the looping.

 

The paddle switch doesnt seem to have any effect on flight control other than disabling the G limiter so you can pull more g's but at slow speeds/high alpha maneuvers I cant notice any effect when using it...

 

So, anyone managed to perform these maneuvers with full success??:) (again, maybe we have to wait for the no pylons FM to be included in order to be able to do it)

 

thanks!!

[Joker328]

Isn't there also an FCS override switch somewhere (separate from spin recovery)? I can't confirm at the moment, but maybe that is what you are looking for.

[IvanK]

Spin mode Its not used in displays. The "pedal turn" you are referring to is invoking "Pirouette logic" which is a specific maneuver that the FCS will permit given specific AOA and Speed limits and specific flight control inputs. In fact when Pirouette logic is invoked certain Yaw rate limits are modified by the FCS that might otherwise call Spin mode.

 

 

Spin mode switch is not something you play with unless you are really in deep S... and the auto engagement of Spin mode has NOT occurred.

[bradleyjs]

I was totally impressed by the EF-18AM demo - really love the high-alpha maneuvers. I’ve seen other F-18C/F demos in the past and this was one of the better ones.

 

Watch how this pilot just floats it in for a touch-n-go and landing starting at 6:50

Edited June 14, 2018 by bradleyjs

[triplec76]

Interestingly enough I was just messing with this yesterday. At the time I didn't understand exactly what the spin recovery switch would do, I just turned it on and waited for magic, I guess.

 

 

Anyway, I got the bird spinning pretty dang good at about the 1 min mark of this video. As someone else pointed out, I later read that the switch just basically overrides any computer input or lack thereof into the controls when a pilot is trying to recover.

 

 

What I've found is that this plane appears to be pretty docile for the most part and I had to work pretty hard to get the turn rate cranked up. I didn't do a great recovery as I was more interested in what little input could be given and not crash, but I almost managed to accomplish that at the same time.

 

 

Edited June 15, 2018 by triplec76

[Ala12Rv-watermanpc]

Isn't there also an FCS override switch somewhere (separate from spin recovery)? I can't confirm at the moment, but maybe that is what you are looking for.

 

it would be interesting to know, yeah...

 

Spin mode Its not used in displays. The "pedal turn" you are referring to is invoking "Pirouette logic" which is a specific maneuver that the FCS will permit given specific AOA and Speed limits and specific flight control inputs. In fact when Pirouette logic is invoked certain Yaw rate limits are modified by the FCS that might otherwise call Spin mode.

 

 

Spin mode switch is not something you play with unless you are really in deep S... and the auto engagement of Spin mode has NOT occurred.

 

Ok, good to know (you said you were a fighter pilot IIRC) from someone experienced on this :thumbup:...Anyway, Im not sure I understand what "Pirouette logic" involves, I mean, what do you mean with that?, is something you must enable in the FCS software of the plane?, something that "auto" enables (when invoked)? or what...also, do you know what are the parameters to correctly perform the pedal turn, I would love to know it.

 

Also, if I understand correctly, you meant that the spin mode indeed auto engage at certain situations even if the switch is NOT enabled???could you elaborate on this please?, thanks.:)

 

 

 

I was totally impressed by the EF-18AM demo - really love the high-alpha maneuvers. I’ve seen other F-18C/F demos in the past and this was one of the better ones.

 

Watch how this pilot just floats it in for a touch-n-go and landing starting at 6:50

 

Yeah, its one of my favourites displays ever, together with the one in the first video...we have some quality fighter pilots in Spain ;)

 

Interestingly enough I was just messing with this yesterday. At the time I didn't understand exactly what the spin recovery switch would do, I just turned it on and waited for magic, I guess.

 

 

Anyway, I got the bird spinning pretty dang good at about the 1 min mark of this video. As someone else pointed out, I later read that the switch just basically overrides any computer input or lack thereof into the controls when a pilot is trying to recover.

 

 

What I've found is that this plane appears to be pretty docile for the most part and I had to work pretty hard to get the turn rate cranked up. I didn't do a great recovery as I was more interested in what little input could be given and not crash, but I almost managed to accomplish that at the same time.

 

 

 

 

Yeah, the plane flies quite stable even in spin mode enabled but as pointed out by some mates here, its because its not enabled constantly even if the switch is enabled...looking at the DDI's, you can see when its on/off and when you are in a flat spin the screens will tell you where to move the stick in order to leave the risky situation as seen in your video...one thing I noticed as I already stated before is that when the mode engages/disengages (spin switch on) the plane makes a sudden pitch change, I guess due to the leading edge slats change in position but I wonder if this is correct behaviour?? I mean, its VERY abrupt and could potentially be dangerous to make the change so fast dont you think?...to test it just enable the spin switch, then make some kind of hard maneuver so that the AoA increases greatly, then recover and wait for the spin mode to be turned off in the DDI's and you will see how hars the plane makes a crazy pitch bump...

 

 

Btw, cant wait to get the no pylons FM update :joystick:

 

Bye!!

Edited June 15, 2018 by watermanpc

[Vatikus]

Ok, good to know (you said you were a fighter pilot IIRC) from someone experienced on this :thumbup:...Anyway, Im not sure I understand what "Pirouette logic" involves, I mean, what do you mean with that?, is something you must enable in the FCS software of the plane?, something that "auto" enables (when invoked)? or what...also, do you know what are the parameters to correctly perform the pedal turn, I would love to know it

 

[Ala12Rv-watermanpc]

 

Very nice, thanks for sharing...will make some flight test!:)

[Alfa]

Also, if I understand correctly, you meant that the spin mode indeed auto engage at certain situations even if the switch is NOT enabled???could you elaborate on this please?, thanks.:)

 

I already explained that bit in my previous post.

 

When the switch is in "NORM" position, "Spin mode" will automatically be shown on the DDIs when conditions leading to a spin are developing - if they occur, a command to put the stick left or right appear on the DDI. If the pilot complies, the FCS will enter spin recovery mode and "Spin mode engaged" is displayed on the DDI.

 

I.e the display mode is called up automatically, but actual activation is manual.

 

When the switch is in "RCVY" position, "Spin mode" will be shown on the DDIs at once regardless of the situation. If conditions leading to a spin occur, spin recovery mode will automatically engage and "Spin mode engaged" is displayed on the DDI followed by instructions to put stick left or right.

 

I.e. the display mode is called up manually(by putting the switch in "RCVY" position"), but actual activation is automatic.

 

Its all in the NATOPS manual :)

[Ala12Rv-watermanpc]

I already explained that bit in my previous post.

 

When the switch is in "NORM" position, "Spin mode" will automatically be shown on the DDIs when conditions leading to a spin are developing - if they occur, a command to put the stick left or right appear on the DDI. If the pilot complies, the FCS will enter spin recovery mode and "Spin mode engaged" is displayed on the DDI.

 

I.e the display mode is called up automatically, but actual activation is manual.

 

When the switch is in "RCVY" position, "Spin mode" will be shown on the DDIs at once regardless of the situation. If conditions leading to a spin occur, spin recovery mode will automatically engage and "Spin mode engaged" is displayed on the DDI followed by instructions to put stick left or right.

 

I.e. the display mode is called up manually(by putting the switch in "RCVY" position"), but actual activation is automatic.

 

Its all in the NATOPS manual :)

 

Yeah, you are right, it behaves exctly as you described. Many thanks for the detailed info. The NATOPS manual is way too long and detailed for me right now (I have not the time to read ir I mean) so I will stick yet to the actual manual and chuck's guide...maybe in the future if I find the time...:)

[IvanK]

A little more info:

[alfredo_laredo]

To add a little.

when you have the spin switch in "NORM" flight controls are at "CAS" for normal flying.

So to archieve a spin (at least for FCS to recognize it) you need this ccriteria

--121 knots +/-15 knos

--Unscheduled Yaw rate

 

Unscheduled by my understanding means that if you use PRO spin rudder, the FCS doesnt go into spin mode, because the pilot its commanding it, so the FCS avoids entering into a spin.

 

With the switch in "RCVY" you only need.

--121 +/-15 knots

--yaw rate

 

Now you can manually go into spin by using your rudder.

 

Its way easy to enter a flat spin with differential thrust and rudder.

[strikerdg]

As much as it would be nice if the pylons being removed would make the flight model more comparable to the demos shown in this thread, the real issue is the original flight model. It’s good but flawed with hornets that are less draggy than reality and hornets with less pitch authority and high alpha capability than reality. It’s still great though! My 2 cents.

[DummyCatz]

I'm sorry to bump this up but I'd like to continue this topic due to the fact that the FM refactoring is considered finished.

TLDR: switching on the MSRM can give you better roll and yaw performance at high AOA in DCS.

 

In reality you won't usually touch the manual spin recovery mode (MSRM) switch unless you're in a spin demonstration process as described in https://trace.tennessee.edu/utk_gradthes/2312/ and https://trace.tennessee.edu/utk_gradthes/2372/. MSRM also allows you to demonstrate the notorious falling leaf out-of-controlled flight (OCF) according to the paper, otherwise impossible with the FCC OFP v10.7 upgrade, which uses a very effective sideslip and sideslip rate (beta and beta dot) feedback, driving the aileron and differential stabilators to suppress the in-phase roll and yaw oscillation characteristic of the falling leaf. MSRM turns off such feedback so that OCF can be demonstrated.

But in DCS, entering MSRM allows you to achieve a better roll and yaw performance than intended, simply because the lateral and directional stability and controllability at high AOA are extremely good in game, that a yaw departure or sideslip excursion is basically unlikely aerodynamically, without the interference of FCS. There's already been a thread describing the lack of adverse yaw and other aerodynamic effects at high AOA, so you won't be worrying about them either.

Edited April 28, 2024 by DummyCatz

[wilbur81]

On 4/28/2024 at 1:32 AM, DummyCatz said:

I'm sorry to bump this up but I'd like to continue this topic due to the fact that the FM refactoring is considered finished.

TLDR: switching on the MSRM can give you better roll and yaw performance at high AOA in DCS.

 

In reality you won't usually touch the manual spin recovery mode (MSRM) switch unless you're in a spin demonstration process as described in https://trace.tennessee.edu/utk_gradthes/2312/ and https://trace.tennessee.edu/utk_gradthes/2372/. MSRM also allows you to demonstrate the notorious falling leaf out-of-controlled flight (OCF) according to the paper, otherwise impossible with the FCC OFP v10.7 upgrade, which uses a very effective sideslip and sideslip rate (beta and beta dot) feedback, driving the aileron and differential stabilators to suppress the in-phase roll and yaw oscillation characteristic of the falling leaf. MSRM turns off such feedback so that OCF can be demonstrated.

But in DCS, entering MSRM allows you to achieve a better roll and yaw performance than intended, simply because the lateral and directional stability and controllability at high AOA are extremely good in game, that a yaw departure or sideslip excursion is basically unlikely aerodynamically, without the interference of FCS. There's already been a thread describing the lack of adverse yaw and other aerodynamic effects at high AOA, so you won't be worrying about them either.

 

Great find! Following...