Aircraft climbs like mad after take off

[AMEDooley]

It won't clear anything unless you have random faults in the mission. if your mission is designed with out it, what is it actually doing? The point of the BIT is to see if there are any faults in the system, with no random failures there wont be anything but a passed BIT.

[Nospin44]

You only need to set the takeoff trim for carrier launches.

 

You set TO trim for any takeoff. That's why its called takeoff trim.

[Revelation]

You set TO trim for any takeoff. That's why its called takeoff trim.

 

No. You do that during the startup procedures. You can takeoff from land without ever pressing the button to reset the trim without any consequence; other than some annoying warnings.

 

You set trim for carrier launches during the pre-flight checklist.

[Nospin44]

No. You do that during the startup procedures. You can takeoff from land without ever pressing the button to reset the trim without any consequence; other than some annoying warnings.

 

You set trim for carrier launches during the pre-flight checklist.

 

You litterally stated you do not need to set trim for takeoffs outside the carrier. Then state you set it during startup.. that IS setting the trim.... Dont understand what your trying to say.

[Hog_No32]

I think it is a bit of semantics (as so often during forum discussions):

 

First of all, the OP wanted to know what the reason for the unexpected and unusual pitch up behavior could be, trying to follow the standard procedures (hence, no need to discuss what is technically possible without following the procedures).

 

I think we all agree that to a achieve the normal and desired flight characteristics the plane needs to be trimmed for takeoff. 12 nose up for a field takeoff and 16-18 for a carrier launch.

 

„Setting“ the takeoff trim can be achieved in different ways, but the normal procedures prescribe to always press the T/O trim button (which by the way not only set the stabs to 12 up but also neutrals the roll and yaw trim). That sets the trim for a field takeoff. For a carrier launch you additionally have to manually trim it further to 16-18 to have the correct takeoff trim set.

 

@Bladders46: Could you maybe attach a screenshot of your FCS page just before you start your takeoff roll? Or a track file (...but I won’t be able check that before Tuesday when I get back to my rig).

Edited June 2, 2019 by Hog_No32

[Ala13_ManOWar]

It happened to me a couple times, I believe it was related to having run the FCS test while forgetting to set flaps to up-auto, so after airborne auto-T/O-trim wouldn't return to 0 as it does when flaps up and it remains in 12 stab up configuration (seen in FCS page and also in stabs physically pointing upwards). Also trimming doesn't work properly so it can't be undone. It's just I forget sometimes to set flaps because I use the three position switch in the Warthog, the switch is hidden behind the throttles :doh:, and I try to do the start-up by heart.

 

I think it's just a failure in following the checklist in it's entirety and in the correct sequence. I know there are short checklists (which I don't use) but I'm sure those also do the minimum required and in the correct order.

 

S!

[Badders46]

I will try and grab screenshot if I can (I fly in VR) and attach it here

 

I have started to do flaps up for the FCS test and it seems to climb a lot still but I can put up with this... I watched a video this morning of F18s taking off and their elevators/stabs were nowhere near as angled as the DCS trim but I guess they might not have been the exact model? Think they were Super Hornets...

 

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[Count Sessine]

I get this too sometimes. Can't figure out what causes it, fyi.

[FalconPlot16]

i set my stab trim to 16 degress (43000 weight) still having that issue i bet it has something to do with flaps

[Knives]

I will try and grab screenshot if I can (I fly in VR) and attach it here

 

I have started to do flaps up for the FCS test and it seems to climb a lot still but I can put up with this... I watched a video this morning of F18s taking off and their elevators/stabs were nowhere near as angled as the DCS trim but I guess they might not have been the exact model? Think they were Super Hornets...

 

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FCS Test bit is bugged. There are several complaints about it.

 

But, remember to Reset the FCS before swithching flaps to auto.

 

Another thing make sure the NWS is disengaged and flaps to Auto before performing the FCS test.

 

There is a couple of points you have to remember:

 

Takeoff trim is very important to ensure the aircraft lift off and climb away from ground. 12 degrees for airfield and 16 to 19 for carriers (depending on how much you are heavy).

 

And all of that, of course with Half flaps. The flaps are necessary for flying under a certain speed so that the wing can generate enough lift.

 

There is a term called flap speed. Each configuration of flaps has a certain speed.

 

I think for F-18 the flaps speed are as follow:

 

Half flaps = 250 knots

Full flaps =175 knots

 

If your speed is at or below 175 lower the flap to full, and above it rise it to half.

 

Below 250 lower your flap to half, and above it rise it to auto.

 

The takeoff configuration is considering lifting off with half flaps and gear down. So when you raise the flap the nose will go up and the same happens when raising the gears. So nose up is expected when you are accelerating and lowering your drag. You have to correct for that if you wish by pitching down and re-trim.

Edited June 2, 2019 by Knives

[maxTRX]

I haven't seen any video footage of OP's "mad climb" so I can't speculate whether it's related to his controls setup or something else...

Somehow I strongly suspect he's experiencing Hornet's unfinished PA mode (FCS). Just throwing it out there... again:smartass:

[Wizard_03]

It happened to me a couple times, I believe it was related to having run the FCS test while forgetting to set flaps to up-auto, so after airborne auto-T/O-trim wouldn't return to 0 as it does when flaps up and it remains in 12 stab up configuration (seen in FCS page and also in stabs physically pointing upwards). Also trimming doesn't work properly so it can't be undone. It's just I forget sometimes to set flaps because I use the three position switch in the Warthog, the switch is hidden behind the throttles :doh:, and I try to do the start-up by heart.

 

I think it's just a failure in following the checklist in it's entirety and in the correct sequence. I know there are short checklists (which I don't use) but I'm sure those also do the minimum required and in the correct order.

 

S!

 

FCS Test bit is bugged. There are several complaints about it.

 

But, remember to Reset the FCS before swithching flaps to auto.

 

Another thing make sure the NWS is disengaged and flaps to Auto before performing the FCS test.

 

 

FCS ibit is performed with flap switch at half not auto. After engine start before taxi, press FCS reset (the flap switch was set at Full before starting the engines) then select auto flaps and press FCS reset again this time hold the paddle switch simultaneously, then select half flaps and perform the FCS bit. Then trim check yada yada..

[Badders46]

Thanks again chaps! I'll give this a go and see how I get on. Appreciate all of your help!

 

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[Ala13_ManOWar]

FCS ibit is performed with flap switch at half not auto.

Unless that's a recent change in the process, that's not what my checklist (following the start-up mission) says. On the contrary, flaps auto just before BITest, and half right after.

 

 

S!

[Wizard_03]

Unless that's a recent change in the process, that's not what my checklist (following the start-up mission) says.

 

 

S!

 

Not sure what checklist your referring too but that’s the procedure for the pre-flight FCS ibit. (Assuming the FCS successfully reset on the first push of the button).

Edited June 2, 2019 by Wizard_03

[backspace340]

Two things -

 

1. You don't have to run any BITs or fire tests or anything (assuming you have random faults off), there are no negative consequences from skipping them in DCS. As long as you press the T/O Trim and FCS Reset button on a field and set your flaps to half, you don't need to do anything else to have a perfectly normal take off.

 

2. You can cause a 'mad climb' by setting your flaps to auto before takeoff. I'd suspect the problem lies there - but a track would help confirm what's going on.

[Ala13_ManOWar]

Not sure what checklist your referring too but that’s the procedure for the pre-flight FCS ibit. (Assuming the FCS successfully reset on the first push of the button).

IIRC just noted down the start-up mission steps. But it wouldn't be the first time something changes later, that's why I say I can't discard that. Anyway my checklist steps do work and it doesn't only when I forget something starting up from memory. BTW my FCS resets fine if I previously push twice master caution button as noted by Wags in his start-up video. I guess problems arise when people start saying "this is not necessary, that isn't either, I cut corners in my start-up and everything is fine". If you cut corners regularly it's easier to miss some necessary step.

 

2. You can cause a 'mad climb' by setting your flaps to auto before takeoff. I'd suspect the problem lies there - but a track would help confirm what's going on.

Yep, I think there's something with that either, since you didn't flaps up because they were already there auto-trim doesn't disengage properly. Just lowering flaps to half and raising again should do the trick.

 

S!

Edited June 3, 2019 by Ala13_ManOWar

[P.Carrasco =Keep Flying=]

I also have that feeling right after taking off and picking up the flats and the landing gear, a small more sudden rise, nothing that hinders the takeoff, as the other pilots have spoken, is normal and expected due to aerodynamics.

[BuzzU]

I just tested it. It will do it if you take off in auto flaps. Take off in half flaps and it's fine.

 

At least for me.

[Preendog]

Not to necro this but,

 

Has anyone learned why the trim gets nose-up after doing an auto flaps takeoff?

[BuzzU]

Fly by wire has a mind of it's own. I could do without it.

 

Then again it could be a bug.

[sthompson]

... I watched a couple of videos where it suggests that you don't touch the stick and just let the aircraft lift when its ready. This is what I have been doing but it just seems to climb incredibly steep ...

 

Other responses seem to have missed this detail in your procedure. Earlier you said that you are only doing shore takeoffs. Are you really not touching the stick for a shore takeoff? That approach is correct for a carrier launch, but not for a runway takeoff. On a runway I pull back the stick gently at about 100-120 knots and it takes off without significant pitch up. Wheels up as soon as I'm airborne. Flaps to auto around 250 knots.

 

Flight control setup for runway takeoff is as follows: After engine startup I push FCS reset twice and takeoff trim button once and flaps to half before taxiing. That's all. (FCS BIT test seems unnecessary.)

[Badders46]

Other responses seem to have missed this detail in your procedure. Earlier you said that you are only doing shore takeoffs. Are you really not touching the stick for a shore takeoff? That approach is correct for a carrier launch, but not for a runway takeoff. On a runway I pull back the stick gently at about 100-120 knots and it takes off without significant pitch up. Wheels up as soon as I'm airborne. Flaps to auto around 250 knots.

 

 

 

Flight control setup for runway takeoff is as follows: After engine startup I push FCS reset twice and takeoff trim button once and flaps to half before taxiing. That's all. (FCS BIT test seems unnecessary.)

Maybe I need to try rotating a bit earlier (manually) as I watched a couple of videos where it says to let the aircraft rotates on its own... Maybe when I rotate I have too high airspeed and therefore excess lift?! Have been flying the Mustang and Spitfire since Monday so haven't had chance to fly the '18! Thanks guys, I really appreciate your input

 

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[BuzzU]

Are you saying if you set the flaps to half down before taking off it still does it?

[Zyll]

At half flaps, unless you are heavily burdened, an airfield takeoff should actually just pull itself off the runway without needing to apply any pitch. It should be very smooth