cannot reproduce F-15 Speedbrake fails to open until ~55 button presses

[Nealius]

Worked fine up until today, and I haven't changed any of my keybinds. [B] for speedbrake toggle, also mapped to HOTAS. After startup, engines stable, canopy closed, drop flaps and open speedbrakes to check function, the speedbrakes fail to deploy regardless of [B] or HOTAS presses. In the attached track, after switching to F2 external view, I pressed the [B] key approximately 55 times before the speedbrake partially opened. After that it started to function normally.

F15speedbrakes.trk

[Flappie]

I tested with the Caucasus terrain and it works just fine (attached track):

1. Batteries ON (RShift + L)
2. Right Engine ON (RCtrl + Home)
3. Left Engine ON (RAlt + Home)
4. Waiting for engines gauges to stop moving...
5. Speedbrake ON (B) woked right away.

I tested your track with Marianas, took over during the engines spool up, and this time I was able to reproduce your issue.

I then created a new mission on the Marianas terrain with default mission editor settins: no issue.

I then tested with a temperature of 30°C and a QNH of 758 like in your track: no issue.

I have no clue what happened to your mission... Can you please test my track? Once engines are spooling up, hit Escape and click Take Control.

F-15C_cold_speedbrake.trk

[Nealius]

Yours works fine. In the original Marianas mission, I have two Eagle clients: "Eagle" and "JASDF Eagle." The JASDF Eagle is the only one with the bugged speedbrake.

I tested all the variables I could think of: units I added post-2.7.8, factions, liveries, unit name, I even deleted the unit entirely and remade it. No change. I added a third Eagle elsewhere on Andersen and this third Eagle works normally as well. Only "JASDF Eagle" at Parking 176 is bugged. 

I tried moving the jet to 175, and it worked at first. Then after moving the parked Eagles up one slot each to fill the gap left by 176, the bug came back.

Ultimately I moved the entire stack of jets, parked and client, one column east and that resolved the issue.

I tried to reproduce with a new mission, but it wasn't reproducible. It seems there's a weird issue with missions made pre-2.7.8 with that specific column of parking slots on Andersen. 

 

[RhineHornet]

I noticed this as well. IIRC, after startup firts move the control surfaces to their limits (like a preflight check) and then try to deploy the speedbrake with "B" - that worked for me most of the times that issue came up. Just a wild guess, maybe the speedbrake only works after enough hydraulic pressure has been established? Don't know if such a thing is even modelled for FC3 models...

[Sacarino111]

24 minutes ago, RhineHornet said:

I noticed this as well. IIRC, after startup firts move the control surfaces to their limits (like a preflight check) and then try to deploy the speedbrake with "B" - that worked for me most of the times that issue came up. Just a wild guess, maybe the speedbrake only works after enough hydraulic pressure has been established? Don't know if such a thing is even modelled for FC3 models...

Hi.

Yep, I think it is the hidraulic pressure thing... Will try now.

Saludos.

Saca111

[Nealius]

On my end it's not a hydraulic pressure thing. When testing I hit [B] immediately after engines stabilized at 67% RPM. Other Eagles in the same mission don't have a problem. If I move the bugged Eagle to a different parking spot, it's fixed. When I move it back to 176 it's bugged again.

Speedbrake operation in general is annoying with the binary presses. When forming up and needing a quick tap of the speedbrakes, they always fail to stow and get stuck at some intermediate position, needing to be extended and retracted again.

Edited November 28, 2021 by Nealius

[Sacarino111]

Hi.

Sorry, I culdn t reproduce the issue. Smae plane, same country, same parking slot, I could open/close the brake with just one engine on. I'm affraid it is your mission. probably some flight deletted in that spot or similar...

Try a fresh new mission and see if it persists.

Saludos.

Saca111

[WilliamLink]

I thought I could add my 2 cents on this issue. I've noticed this issue with the speedbrake for quite some time, and I don't know whether this is actually a bug or it's how it is designed in the real jet (my guess is this is actually how it's supposed to work), but your speedbrake won't come out when you have a high Angle of Attack. Anywhere above 25 units of AoA makes the speedbrake not operate.

I'm not sure what causes the AoA sensor in the Eagle to go nuts when you're stationary on ground (maybe wind incidence angle?), but you can watch, in a fully stopped and engines off condition, that your AoA Gauge keeps jumping from 0 all the way up to 45+ units, and whenever the needle passes the 25 mark, it prevents the speedbrake from operating. This strange AoA sensor behavior also happens on other jets (I've experienced that with the SU-25 - when its AoA passes a certain limit, the annoying warning sound goes off - and in the Flankers as well), so maybe it is caused by wind. For the Eagle, the side effect of this high AoA is the speedbrake won't move.

Also, when you're in the air, get your speedbrake out and pull a high alpha maneuver, and watch your speedbrake retract automatically when you have the high angle of attack, and it'll come back out when the AoA goes down. This behavior is what leads me to believe this issue is actually a design choice, not a bug. But I may be wrong on that, it needs investigation.

Edited June 12, 2022 by WilliamLink

[Nealius]

This must be related to turbulence set in the mission editor, then. Turbulence causes the AoA sensors to come alive while on the ground in all of the modules, and they're more lively the higher you set turbulence.