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Random Pitch, please help"


GeorgeSloan
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HI guys im finding this aricraft almost impossible to fly, the SU27 pitches up massively almost as soon as i take off throwing me straight into the clouds and beyond until i either fight it or stall. Are there any controls that could be wrong that could cause this to happen, trim certainly isn't doing the trick!

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If your controls are setup properly it is the trim then. You need to constantly change your trim as you increase and decrease airspeed. With takeoff you can expect a large nose up effect because of how fast your airspeed is increasing. Try using afterburner for take off but once your off pull back on the throttle and you shouldnt have to trim as much. But like i said eariler if your controls are set properly its trim you need to do. as much as I find it hard to believe that an aircraft requires so much work with the trim this is probably one of the few cases where you are constantly changing trim. Also, i've yet to run out of trim as some have said.

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1. Check your controller axes. Make sure everything is mapped properly. For the Su-27 consider giving the input response a curvature of between 15-20 for both roll and pitch - this should help to make fine adjustments easier.

 

2. Prior to taking off are you pressing the "S" key at all? If so, DO NOT under any circumstances ever press the S key. What it does is that it disconnects the flight control system and gives you direct boosted control of the control surfaces. This is great for doing manoeuvres such as the Kobra but for inexperienced pilots means death as the aircraft becomes HIGHLY unstable with the FCS disengaged.

 

3. On takeoff, especially with a light load and use of afterburner, you will experience a strong nose-up tendency when you raise flaps. Something to be careful of.

 

Hope these help...

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I can't help but wonder if the pitching is not excessive: I have noticed that around 3-5km MSL, it is impossible to trim this bird for level flight. Full-forward trim still allows the aircraft to nose up unless checked with forward pressure on the stick. I feel like this should not be the case.

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I can't help but wonder if the pitching is not excessive: I have noticed that around 3-5km MSL, it is impossible to trim this bird for level flight. Full-forward trim still allows the aircraft to nose up unless checked with forward pressure on the stick. I feel like this should not be the case.

 

I don't have this problem - Have you edited your curves ? What joystick are you using ?

Cheers.

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I have the same happen, low fuel and no weapons, somewhere around a 1000 TAS, i believe, i reach the gimbals limit, and i can no longer make it trim downward.

 

I'll get tracks of it later.

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I was thinking of starting a thread about this as well. What the heck is wrong with this plane? I entered the Su-33 cockpit and 5 minutes later I had no trouble performing turns, landing, flying straight. I switched to Su-27 and that thing can't fly straight without leaning to the left or to the right for a second. It also keeps climbing and I have to sit down on my joystick in order to prevent it's nose from going into a 15+ climb. I didn't even press the suicide key for disabling fly by wire system yet the plane goes breakdancing when you pull the stick harder. When trying to land, I can't fly straight, it keeps leaning to the left or to the right. One last thing, are the wheels made from paper or something? I can't press W without one of it messing up and then going into a drift, resulting in flames and this happens when I am driving on the runway with 40 km/h. This does not happen on the Su-33 nor the Su-25/Su-25T. When I played the mission Su-27 - Base Defense, it took me around 15 respawns/restarts to actually make it to the runway successfully without one of the wheels getting obliterated because of pressing W while moving at 40 km/h during taxi.

 

Help!

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I was thinking of starting a thread about this as well. What the heck is wrong with this plane? I entered the Su-33 cockpit and 5 minutes later I had no trouble performing turns, landing, flying straight.[/Quote]

That's because the Su-33 still has the old "it flies like it's on rails" flight model, AKA Standard Flight Model.

 

 

I switched to Su-27 and that thing can't fly straight without leaning to the left or to the right for a second.

Not sure what this is about unless you have, perhaps, an uneven weapons load. The Su-27, unlike the Su-33, has a flight model which reacts to uneven loads and drag.

 

It also keeps climbing and I have to sit down on my joystick in order to prevent it's nose from going into a 15+ climb. I didn't even press the suicide key for disabling fly by wire system yet the plane goes breakdancing when you pull the stick harder.

The only time I've ever experienced it breakdancing is when I was unknowingly fighting one of the AP settings. It will react to changes in airspeed but it seems like you're talking about more than that. Unless, of course, you are fighting the trim. You do have to constantly trim for airpeed. According to Yo-Yo, this is actually how the Su-27 is set up. When the Flanker's FBW system was being designed, someone thought it would be a good idea to mimic how light aircraft behave because so many pilots were already familiar with that.

 

One last thing, are the wheels made from paper or something? I can't press W without one of it messing up and then going into a drift, resulting in flames and this happens when I am driving on the runway with 40 km/h. This does not happen on the Su-33 nor the Su-25/Su-25T. When I played the mission Su-27 - Base Defense, it took me around 15 respawns/restarts to actually make it to the runway successfully without one of the wheels getting obliterated because of pressing W while moving at 40 km/h during taxi.

FWIW, which isn't much, I have only blown a tire on rare occasion and, when it happened, I was sort of expecting it. You need to be careful of the airspeed at which you are make turns and how sharp those turns are, especially at speeds over 20 km/hr. In landing, if you touch your brakes before you're below about 120 km/hr make sure you don't stand on them. Just a quick on/off.

 

As mentioned, the aircraft is beta but I think we'll find that, while things will be tweaked, I wouldn't expect any wholesale changes.

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Ironhand, KUDOS to you for taking the time to respond to these mushrooming threads about how terrible the FM of the Su27 is...

 

It's not me, it's the plane...*sigh* is getting old. No one even takes a moment to consider the fact that maybe, just maybe the plane behaves the way it does on purpose.

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not sure this is even related - i've only had this a couple times - and this is in the f-15 (i only fly the f-15) but i've heard guys in the flanker report it also..

 

but i've had a blackout on the take-off roll

 

again, only (maybe) three or four times ---- ever

 

but its an *instant* black screen - then in a couple/few (excruciating) seconds vision fades back in

 

just wondering if "maybe" these issues could be related - seeing as both are FC3

 

??

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That's because the Su-33 still has the old "it flies like it's on rails" flight model, AKA Standard Flight Model.

 

Sorry, I didn't know the aircraft was in beta. I had no clue really why the Su-27 and the Su-33 had such a big difference in control but now I get it.

I guess the difference applies to the tires as well, whatever I do I can not blow a Su-33 tire but I can barely manage to not blow a Su-27 tire at the same time.

 

By the way, when trying to air refuel what should I trim, yesterday I did my first successful air refuel (with Su-33 of course) even though I had to retry like 10 times I was able to hold each time for more than 10 sec and from 40% refueled to 100%. But I read somewhere that you can make the plane not lean sideways and maintain altitude, as for the speed I don't know if it can be trimmed I just kept spamming B for the air brakes whenever I was going to exceed the tanker's speed. :joystick:

 

Thanks for your reply, helped a lot.

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...

 

It's not me, it's the plane...*sigh* is getting old. No one even takes a moment to consider the fact that maybe, just maybe the plane behaves the way it does on purpose.

More than anything, it's a matter of expectation. FBW systems are trajectory control systems making an aircraft a sort of point and shoot affair. Point your nose in the direction you want and you'll keep moving in that direction even if your airspeed, etc change. In point of fact, if you read the description of the Flanker's FBW system in our manual, you'll realize that that is also the underlying system the Flanker has.

 

If you stop reading at that point, however, you miss some salient paragraphs which follow, the ones stating that the Flanker has an added airspeed trimming law. This law causes the leading edge of the horizontal stabilizer to deflect down as airspeed increases and up as it decreases. In other words, it'll raise the nose as speed increases and drop the nose as it decreases. This is what I was referring to above. Someone, somewhere along the line decided that adding this law would make the Flanker safer and/or easier to learn to fly.

 

EDIT:

Sorry, I didn't know the aircraft was in beta...

 

...yesterday I did my first successful air refuel (with Su-33 of course)....

It's beta but, like I said, I don't think there are going to be any wholesale changes in how it handles.

 

Congratulations of refueling. :) It's been a very long time since I've done anything interesting in the Su-33, so I don't have much I can share concerning that platform.


Edited by Ironhand

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whatever I do I can not blow a Su-33 tire but I can barely manage to not blow a Su-27 tire at the same time

 

Planes with SFM also have 'SGPM' - standard ground physics modelling. You cannot make the tyres on the Su-33 slide, and because of this you cannot burst them when turning/braking. This mean people can develop bad habits with no feedback.

If you keep your speed to realistic levels - particularly during turns - you shouldn't be having tyres burst while taxiing. If you watch your speed & are still having problems, then as Ironhand said, you might want to check for control conflicts.

 

Also - the flaps increase lift, but also cause a nose down pitch (by moving the center of lift backwards). As you lift the gear and flaps, you have to trim the nose down to remove the pitch up that occurs as you lift the flaps (& the opposite as you drop the gear and flaps to land). You should start doing this as soon as you hit "G & F"

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Cheers.

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...

 

Also - the flaps increase lift, but also cause a nose down pitch (by moving the center of lift backwards). As you lift the gear and flaps, you have to trim the nose down to remove the pitch up that occurs as you lift the flaps (& the opposite as you drop the gear and flaps to land). You should start doing this as soon as you hit "G & F"

:) Or you can "cheat" like I often do and dial in some nose down pitch before you start your takeoff roll. That minimizes that initial pitch shift when you retract the gear.

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You cannot make the tyres on the Su-33 slide, and because of this you cannot burst them when turning/braking. This mean people can develop bad habits with no feedback.

 

Yes, when I decided to begin flying the Flanker, I started with Su-33 because I wanted to do carrier landing, when I gave the Su-27 a try I was horrified and that habit I developed with the Su-33 tires is really painful when using the Su-27.

 

Thanks for reply, helpful tips. :)

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:) Or you can "cheat" like I often do and dial in some nose down pitch before you start your takeoff roll. That minimizes that initial pitch shift when you retract the gear.

 

 

:)

 

Maybe it' s 6 & 2x3 , or your's might be the better option with a non-FFB stick.

 

I use an MSFFBII & if I hold trim down (or up as the gear & flaps lower) the trim is added at pretty much exacly the same rate aas the pitch increases, so if I start trimming down as soon as I've retracted the gear & flaps, the stick forces stay pretty much constant to hold the plane in the intended path, the stick just moves forward (or back)..

Cheers.

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:)

 

Maybe it' s 6 & 2x3 , or your's might be the better option with a non-FFB stick.

 

I use an MSFFBII & if I hold trim down (or up as the gear & flaps lower) the trim is added at pretty much exacly the same rate aas the pitch increases, so if I start trimming down as soon as I've retracted the gear & flaps, the stick forces stay pretty much constant to hold the plane in the intended path, the stick just moves forward (or back)..

Ahhh... that makes sense. My stick is definitely not FFB. :)

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I'v also noticed that Su-27 trim-scales the joystick, -100 always corresponds with cockpit stick fully forward and +100 fully backwards, regardless of trim. I wonder how much this contributes to controlability issues. IIRC Su-33 doesn't do this. Does this come with AFM?

Abandon all hope, ye who enter here.

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