Cat Launch after a first trap

Hello,

I was wondering if the pull up done by the FCS after being launched by a catapult was correct.

With the exact same loadout, weight, flaps and trim :

If you have just started the plane and took off from the carrier, the pull up is not aggresive (barely any Gs and ~8 units of AoA) and you have good authority on the Stabilizers.

If you launch from a catapult after having trapped a first time, the pull up will be hard (more then 4 Gs and around 14 units of AoA) and for some reason, even with full stick forward the plane will not go nose down.

I'm pretty sure there is a problem here but please explain if i am doing something wrong :).

Cheers,

Rex.

EDIT : I'll get some tracks and/or maybe a video tomorow.

Hmm... Have you checked your trim settings?

Hmm... Have you checked your trim settings?

It is written in my first post that indeed trim was the same.

EDIT : And correct. Sorry i misread your post

Before a cat launch I always press and hold the TO TRIM button until TRIM appears in the left DDI, then afterwards I manually set 16° nose up trim according to my weight as per the manual. Never had any extreme pitch after launch.

The one time I did have a crazy pitch-up moment was when I failed to do the above procedure before launch.

Before a cat launch I always press and hold the TO TRIM button until TRIM appears in the left DDI, then afterwards I manually set 16° nose up trim according to my weight as per the manual. Never had any extreme pitch after launch.

 

The one time I did have a crazy pitch-up moment was when I failed to do the above procedure before launch.

I'm testing it right now, will post when i have the results, but it's not a trim issue.

I have (once) had an issue with extreme nose up and not responding well to forward stick, but I've done many cat launches after hot refuel/rearm and I don't usually see any difference. Is it repeatable every single time for you?

Every time this happened to me, it was because I left flaps in auto and flicking them down and up fixes the FCS's desire to be the next Space-X. The other thing is that the stabs reset to 12 ^ if you reset trim and they should be set to the take off weight as far as I understand, so depending on your weight, trimming seems to be counter productive as you have to set it again correctly. Loaded weights are stabs from 16-19 and you have to consult the manual for the number against your checklist weight.

I found one tacview file that was complete, i had a hard time landing so it's a bit long but it does showcase my problem :

First launch : 43000Lbs, 5xMk-83s, two tanks, 2xAIM-9Ms, flaps half, trim 17°NU

Rotation at 155 kts, 9.8° of AoA, 1.1G pull

After hot rearm : 43000Lbs, 5xMk-83s, two tanks, 2xAIM-9Ms, flaps half, trim 17°NU

Rotation 154 kts, 13° of AoA, 1.2G pull and i had a hard time getting the aircraft to the desired attitude

This is only one example with a heavy loadout but i had the problem with much lighter loadouts and always after a first landing.

This was on a multiplayer server with a stationnary carrier, the aircraft started wings folded, cold with no payload.

https://drive.google.com/file/d/1RzbfywLgxFwX7ZahJZ-qeA4RkpEZj_81/view?usp=sharing

First launch at 5:10:50ZULU, second at 5:28:48ZULU

Another test after today's update, this time with a moving carrier (around 25kts head wind) and same behavior, first launch, i stay at around 9° of AoA and i do not need to push full stick forward to keep the aircraft level.

Second launch, the aircraft takes 14° of AoA and alot more forward stick is needed to keep the aircraft level.

The track showed that i crashed instead of trapping so i only have a tacview file.

https://drive.google.com/file/d/1UaZ8Tms3W7kdyeLpa2CPiSixRLOcGcX-/view?usp=sharing

This post can be moved to the bug section, my friends are also experiencing this behavior.

P.S : I've also attached the mission i was using.

I have been doing multiple cat launches after landing - lot of fun.

I always hit Take Off trim button along with full flaps prior to launching and do not have any issue.

Not sure if that is right or wrong procedurally, but seems to work good for me.

To the OP. Is your trim for T/O the same as for landing?

Here is a video, i have the controls indicator at the bottom right, as for the AoA indexer on the HUD it shows similar figures to what was in the tacview i sent in my last post because it was the exact same mission and loadout.

P.S. : Don't mind the horrible recovery ^^

To the OP. Is your trim for T/O the same as for landing?

Yes my trim was correctly set for my loadout, both launches.

It would be very nice if a moderator could move back this post to the bug section, which is where I originaly posted but due the lack of evidence was moved here.

I have already asked a moderator a few days ago, but did not get an answer, usually these requests are dealt with pretty quickly. (I'm not complaining)

Yep early access.

I can take off from cat position trim 0 and without cat launch in a light jet.

Trim 16 right know seem to really jerk the jet.

I can land on the boat by going hard aoa 20 over the wires and not brake the jet.

So early access ;)

I had the same issue before. What I did to resolve it, after going through the shut down procedure and before shutting down the right engine I turn off the Mission computer. First I trun off MC 2 for 10 sec then MC 1 for another 10. If you do so you will see both DDI blink "Stand by" then every thing is restarted except few things related to HSI and others few.

Also make sure after you set the takeoff trim, the numbers on the left matching the number on the right on FCS page. Sometimes if you applied left or right trims, it remains and do not reset.

Doing all the above I launched from the carrier 3 times after refueling and rearming just as my first.

Sent from my E6833 using Tapatalk

This issue is still very much present in game, every time I launch from a catapult after landing or take off from a runway after landing, with the same payload and trim setting then on first take off, not touching the controls, the FCS pulls up way harder and prevents me from pulling the nose down with the stick, the same can be observed if you bolter on the ship, the FCS will pull up hard after you leave the ramp and it's almost impossible to pitch down for a few seconds.

EDIT : i'll come around to gather the essential information and create a bug report.

If I'm staying in the pattern I'll go to flaps full and start pitching down so I don't bust 600 feet. You have to man handle the jet a bit but with 16° NU it's to be expected.

On a normal launch I get the flaps up immediately and then there' no need to be rough on the controls.

If I'm staying in the pattern I'll go to flaps full and start pitching down so I don't bust 600 feet. You have to man handle the jet a bit but with 16° NU it's to be expected.

 

On a normal launch I get the flaps up immediately and then there' no need to be rough on the controls.

We're talking about a departure here, the FCS acts as if you boltered even if you have landed and when you take off for the second time, it's pulling up and really doesn't allow you to pitch down (the exact same behavior observed after a bolter).

This can't be correct, the FCS gives you good authority and pulls up enough to keep your aircraft at 8.1° of AoA just after rotating if the airframe you are using has not flown beforehand.

Also an F/A-18C pilot who tested the DCS module described the behavior of the FCS after a bolter is incorrect, and that along time ago, i'll try and get the video, in the mean time the youtube channel is called A.E.W.

Have you tried cycling flaps to Auto and back to Half before takeoff?

Have you tried cycling flaps to Auto and back to Half before takeoff?

I'll have to do more tests with heavier payloads but it seems that with a fairly light aircraft the problem is no more or at least alot less noticable, but that's probably just me, after cycling the flaps, thank you.

But this is not indicated in the DCS manual, I don't think it is in the landing lesson, this is something that has to be added.

Attached is the NATOPS checklist, it's not complete but putting the flaps in auto is one of the first items. I should have dug this up ages ago.

Regards,

Rex.

No problem!

I've had uncontrollable pitch-up takeoffs as well in various scenarios but its been completely solved by cycling the flaps back to Auto and then to Half, it seems to reset the FCS/Trim mode and puts things back to normal. Its now become part of my normal checklists.

I've never payed a lot of attention to this detail. But as developers they are probably wanting to get all the systems completed in the module before they tweak the flight model and systems to perfection. Sometimes adding things break things later on. Also, tweaking is best done with all systems completed. Then when they are tweaking the flight model they can make sure it works with everything they coded in.

I'd say keep giving them data though. As we have seen, the moderators keep a close eye on things and I'm sure they forward these concerns to the developers whether it is in bug reports or not.