Su27 inverted depart is realistic?

[Darkwolf]

nearly no airflow on the rudder at 90° !

 

Wouldn't it be better to use disymmetric thrust ?

[Ironhand]

Hang on, watch the track closer and as he said> I see no reason why this can't be. Its plausible.

 

He primarily used his engines to turn not his rudder.

I'll have to watch them again from external view. I had switched to the cockpit in order to have the controls indicator up. Either it doesn't show a split throttle or I completely missed it. All I saw was the rudder going full over. Then again, it was 4 AM and I was still on my first cup of coffee. So that might explain a lot.

 

Using asymmetrical thrust it might be possible. But, given the AoAs involved, I can't imagine anything but decelerated, turbulent air moving past those rudders.

[Ironhand]

I'll have to watch them again from external view. I had switched to the cockpit in order to have the controls indicator up. Either it doesn't show a split throttle or I completely missed it. All I saw was the rudder going full over. Then again, it was 4 AM and I was still on my first cup of coffee. So that might explain a lot.

 

Using asymmetrical thrust it might be possible. But, given the AoAs involved, I can't imagine anything but decelerated, turbulent air moving past those rudders.

OK. I checked this morning. It's the asymmetrical thrust that's doing it. There's no apparent rudder authority in the midst of the cobra.

[theropod]

friends ,thank for your interests!

 

ironhand thank you for attentive analyzing:)

at all my tracks ,i have used rudder because of testing that if it is helping the turn movement. but i've noticed that there is no rudder function while turning down.

yes your observations true ,at the top of cobra, i've used opposite elevator to pull back left and left thrust to turn right down

 

edit: i've installed todays new patch and just performed the same maneouvre with no rudder,only elevator with supplying thrust and performed it more quicker i guess.

but more tests needed.

cobraturn test Track.trk

Edited January 9, 2015 by theropod

[BeachAV8R]

This is a problem. Just a bit of negative G without pressing any buttons is causing me to black out, and the plane enters some sort of scripted inverted behavior. I've had it happen twice on the last five missions.. The fact that you can't eject or anything means something wonky is going on...

 

I just spent 40 minutes flying a mission only to have it all for nothing because I bunted the nose slightly to join up with another flight... I wasn't hitting any buttons or anything... Very frustrating..

 

BeachAV8R

[theropod]

deleted

Edited January 10, 2015 by theropod

[GenericFloat]

This is a problem. Just a bit of negative G without pressing any buttons is causing me to black out, and the plane enters some sort of scripted inverted behavior. I've had it happen twice on the last five missions.. The fact that you can't eject or anything means something wonky is going on...

 

I just spent 40 minutes flying a mission only to have it all for nothing because I bunted the nose slightly to join up with another flight... I wasn't hitting any buttons or anything... Very frustrating..

 

BeachAV8R

 

I've noticed this on occasion as well. It happens rarely to me, but sometimes pitch it down too much too fast, and the pilot will die and the Flanker without pilot input eventually turns inverted and spins down to the deck like a leaf. I think it only happens when you're past 700kph. I don't think it's scripted however, I think it's something to do with negative gs and pilot endurance (maybe the pilot's head exploded or something). Dunno if it's a bug or not.

 

I generally think the flight model is pretty good, but very unforgiving.

[Keakaha]

Has anyone been able to perform a "kulbit" as seen in this video https://www.youtube.com/watch?v=-2dgi2NhMSw or the end over end tumbling descent in this video https://www.youtube.com/watch?v=eFjO-kWuBBE @ 44seconds and again @ 5:15 marks.

 

Or does this require thrust vectoring?

[mvsgas]

Both videos are of Thrust vectoring aircraft. So yes, thrust vectoring is needed to perform those maneuvers as seen in the video by those aircraft. Both aircraft in the video where/are prototypes and we do not have them in DCS.

Edited February 25, 2015 by mvsgas

[Fri13]

I don't believe at all that is realistic as I have hard time to believe that Soviet engineers and pilots would have allowed a such FBW and limiter that allows pilot to kill himself and do stunts just after the take off at speeds like 270-280 that crash plane on the deck with very slight movements.

 

A friend tried the take off first time after PFM release and after dozen or so take off he got once in air further than kilometer and even that ended up to inverted depart because suddenly the screen went black and caused plane to go negative pitch and after couple seconds screen came back plane was diving directly on ground. That from steady straight 800+ km/h speed.

 

When watching videos from real Su-27 cockpit the pilots can do large movements with stick, that would lead in DCS to exempt of suicide.

 

Yes the plane behaves OK at slow speeds when maneuvering radically but still something just feels wrong as I can fly with direct control better than it enabled.

[OnlyforDCS]

I don't believe at all that is realistic as I have hard time to believe that Soviet engineers and pilots would have allowed a such FBW and limiter that allows pilot to kill himself and do stunts just after the take off at speeds like 270-280 that crash plane on the deck with very slight movements.

 

A friend tried the take off first time after PFM release and after dozen or so take off he got once in air further than kilometer and even that ended up to inverted depart because suddenly the screen went black and caused plane to go negative pitch and after couple seconds screen came back plane was diving directly on ground. That from steady straight 800+ km/h speed.

 

When watching videos from real Su-27 cockpit the pilots can do large movements with stick, that would lead in DCS to exempt of suicide.

 

Yes the plane behaves OK at slow speeds when maneuvering radically but still something just feels wrong as I can fly with direct control better than it enabled.

 

I have no idea what you are talking about, the plane is extremely well behaved with FBW on! It's the most stable jet we have in the game (apart from the A10C)

[Azrayen]

That's gross exageration, OnlyForDCS...

[Fri13]

That's gross exageration, OnlyForDCS...

What is?

[Fri13]

I have no idea what you are talking about, the plane is extremely well behaved with FBW on! It's the most stable jet we have in the game (apart from the A10C)

That the plane FBW is not there dampening or changing reaction speeds based what kind a stick movement is at different speeds, making it extremely easy to push plane to inverted or requiring constant careful movement not to overshoot.

 

This even with 45cm long extension in joystick, FFB or it disabled and adjusted curves/sensitivity.

F-15, KA-50, Mi-8 and Mig-21 fly very well, A-10C has as well very sensitive control movements required.

Like with even alone trimming Su-27 for forward flight means stick is 85-95% ahead in axis range, adjusted curves or not.

 

Watching real cockpit stick movements, the plane acts totally different than in DCS to similar movements.

[Ironhand]

...

Watching real cockpit stick movements, the plane acts totally different than in DCS to similar movements.

Can you possibly link some of the videos you're referencing? I'd like to take a look at them.

[OnlyforDCS]

Sounds to me like there are a lot of people that have gotten used to the SFM handling of the bird and are now complaining that the plane is too hard to fly with the new FM. I have never flown the SFM versions of the FC3 planes in DCS World so I don't have anything to compare it to previously, but I trust the developers of the FM more than I do random people online who claim to have 'expert' knowledge on how the plane is supposed to handle. That is in adition to numerous western reports of pilots who have flow the RL Su27 and stated that it requires requires a higher workload from the pilot compared to it's western counterparts.