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Is the MiG-29 PFM correct now?


Xtan

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I think he's referring to the nose lowering tendency as they open and thrust increases.

 

I am wondering whether there isn't a direct aerodynamic effect involved as well - i.e. as airflow enters the intake duct(instead of passing it), you could imagine that this would cause a "down force" effect.

JJ

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I am wondering whether there isn't a direct aerodynamic effect involved as well - i.e. as airflow enters the intake duct(instead of passing it), you could imagine that this would cause a "down force" effect.

Perhaps...though the manual only specifies the increased thrust.

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The thread is about the MiG-29, not sure why you mention 'other aircraft types'. :)

 

I didn't - he did;

 

The only unusual thing I see here is the thing with the intake duct. The rest is common for most other planes.

 

But anyway, I didn't know what he was talking about initially, thanks for the clarification.

 

NP :)

JJ

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Perhaps...though the manual only specifies the increased thrust.

 

Well maybe I am wrong, but thats not exactly how I interpret it:

 

Premature aggressive rotation leads to early liftoff due to significant vertical component of thrust adding to aerodynamic lift. If the gear is then raised too early, the momentary loss of total lift associated with lower intake duct opening causes a momentary decent and possible contact of the A/C structure with the ground.

 

The first part talks about thrust adding to aerodynamic lift, while the latter about loss of lift when the gear is raised and ducts are opening...although the thrust increases(?).

 

...During lower intake duct opening, a noticeable thrust increase and a nose lowering tendency are experienced.

 

More like two different effects conspiring to complicate things. :)


Edited by Alfa

JJ

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Well maybe I am wrong, but thats not exactly how I interpret it:

 

 

 

The first part talks about thrust adding to aerodynamic lift, while the latter about loss of lift when the gear is raised and ducts are opening...although the thrust increases(?).

 

 

 

More like two different effects conspiring to complicate things. :)

You're probably right. But, since they open at 200 km/hr in the sim and I usually rotate at around 210-220 depending, I've never really noticed anything. Tried purposely rotating early and the nose did drop as they opened but I'm not sure that it wasn't just my stick control.

YouTube Channel: https://www.youtube.com/channel/UCU1...CR6IZ7crfdZxDg

 

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In the attached track, I take off with 100% fuel in full AB. At the beginning of the takeoff run I pull the stick completely.

 

 

Watch the aircraft from outside at 1/4 speed. The nose gear lifts off the runway at 75 Km/h. The aircraft has so much desire to rotate even at such ridiculously slow speed, I actually have to push the stick to stop the nose up motion. By the time the speed reaches 130 Km/h, I'm already at the required 10 deg standard takeoff pitch attitude, with the stick pushed completely!

 

 

I'm not saying the real flight manual says to pull the stick completely on takeoff. It doesn't.

 

 

But the behavior I described above is laughable. There is no supersonic aircraft of any era that can be rotated on takeoff at 75 Km/h. Not even close.

 

 

I know when the axial air intakes open at 200 Km/h there is a nose down moment and an additional stick pull is necessary to maintain the pitch, this is described in the real flight manual. In simulator the additional stick pull is moderate and I see no problem here. But in the attached track I tried to maintain precisely 10 deg pitch during takeoff run and immediately after getting airborne. The feel of the aircraft in pitch is incredibly wobbly. As if it has almost no angular inertia. Several very fast control inputs are necessary but precise pitch control is close to impossible IMO. And no, it's not a matter that I don't use enough curvature on pitch axis. I use much much more curvature than I usually do on fast jets, but it's still kinda in vain.

29TO.trk

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I think this conversation is moot, since every other model in the past always changes but:

The nose gear lifts off the runway at 75 Km/h.

 

Could you do that without AB? I could not. So I wonder how much of it is control related, (the interaction of the flight controls) and how much is it about the thrust. It could be the alignment of the thrust or how much the thrust is affecting pitch.

 

Lets keep in mind that we are doing stuff in DCS no pilot attempts in RL. Probably a reason for that.


Edited by mvsgas

To whom it may concern,

I am an idiot, unfortunately for the world, I have a internet connection and a fondness for beer....apologies for that.

Thank you for you patience.

 

 

Many people don't want the truth, they want constant reassurance that whatever misconception/fallacies they believe in are true..

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...So I wonder...how much is it about the thrust. It could be the alignment of the thrust or how much the thrust is affecting pitch.

...

I was just stopping by to say just that. I took control of Fox One's track and waited for the full afterburner to kick in before releasing the brakes. The resultant unloading of the front strut combined with the added thrust component was enough to kick me up to 6° pitch with the control stick untouched.

 

I've attached Fox One's track with me taking control. I waited until full afterburner thrust was developed before releasing the brakes. (You'll know you're there because you'll start rolling with the brakes still fully engaged.) As the brakes release, you can see the front strut fully unload and pitch the nose up. Interestingly enough, the nose rotates at around 65-70 k/h with my hand completely off the stick.

 

BTW, the trim is at the default takeoff trim which is actually slightly nose down. Or, at least, it looks like Fox One just accepted the default takeoff trim.

MiG-29A Fox One Track TO2-V.trk

YouTube Channel: https://www.youtube.com/channel/UCU1...CR6IZ7crfdZxDg

 

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In my opinion the FM has been made too difficult to master for an average simulation user (like me). I land well with all the simulated models (even with the Mig-21!) Because I faithfully follow the indicated landing procedures. But for two days I'm trying to make a landing with the "new" Mig-29 (following the instructions on the flight manual of the real Mig-29 !!!) and the result is that on dozens of attempts only a couple have gone well. Engine power management is a nightmare and it is already a problem to reduce speed. Then the plane bounces unrealistic even in level flight up to the touchdown. Moreover, despite the parachute and the brakes, at 250/300 km / h the plane stops right at the end of the runway. And be careful not to touch the rudder on the run ... the plane crashes catastrophically (there is no command for the NWS!). Below is a graph of the Mig-29 landing procedure (the real one).

Landing.pdf

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flavnet said:
In my opinion the FM has been made too difficult to master for an average simulation user (like me). I land well with all the simulated models (even with the Mig-21!) Because I faithfully follow the indicated landing procedures. But for two days I'm trying to make a landing with the "new" Mig-29 (following the instructions on the flight manual of the real Mig-29 !!!) and the result is that on dozens of attempts only a couple have gone well. Engine power management is a nightmare and it is already a problem to reduce speed. Then the plane bounces unrealistic even in level flight up to the touchdown. Moreover, despite the parachute and the brakes, at 250/300 km / h the plane stops right at the end of the runway. And be careful not to touch the rudder on the run ... the plane crashes catastrophically (there is no command for the NWS!). Below is a graph of the Mig-29 landing procedure (the real one).

I saw this post and flew a mission based on the PDF. Uploaded it to YT and, then, discovered a post from you in another thread indicating that you now are having success. Congratulations! Glad you got it sorted out. Anyway, I'd hate my effort to go completely to waste. So here's the video, anyway, in case it might help someone else.

 

 

 

 

I also have one of a road landing that I'll post a bit later today.


Edited by Ironhand

YouTube Channel: https://www.youtube.com/channel/UCU1...CR6IZ7crfdZxDg

 

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b_pCzVjDyjQ

Perfect! 2 questions:

 

1. Always left runway side - a habit from formation landing?

 

2. What are you looking at on the left panel after landing?

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...

 

The trim now resets correctly to center.

 

The autopilot is still a bit mad....

...

 

If you're referring to aileron trim, then it's not truly centering. That's what your image is indicating. The AP is continually have to retrim to adjust for the roll.

YouTube Channel: https://www.youtube.com/channel/UCU1...CR6IZ7crfdZxDg

 

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This is happening with neutral aileron trim; it's not a new thing -

 

https://forums.eagle.ru/showthread.php?t=222109

That's because "neutral" is not actually centering it. That was and continues to be the issue. If it were truly centered, none of this would be happening because there would be no continual correction required. You're right. The aileron trim thing has been there from the start. Unfortunately it has not yet been fixed.

YouTube Channel: https://www.youtube.com/channel/UCU1...CR6IZ7crfdZxDg

 

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Perfect! 2 questions:

 

1. Always left runway side - a habit from formation landing?

 

2. What are you looking at on the left panel after landing?

 

1. No particular reason. I just seem to gravitate to the left side. Maybe the margin between the grass and runway helps my judgement. Since all these are of me alone, it doesn’t create a problem.

 

2. Glancing down toward the keyboard to locate the “W” key... :)

YouTube Channel: https://www.youtube.com/channel/UCU1...CR6IZ7crfdZxDg

 

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