Roll rate to slow. (1.5.4.)

[CoBlue]

Latest patch 1.5.4.

 

The roll-rate is app. 3-2 times slower then before, the 21 rolls more like a WWII fighter now. At 7-900km/h the slow roll rate is very apparent.

What was the reason for dumbing it down?

 

Look at the videos & compare:

https://youtu.be/0-cEdwgYdAw?t=9m8s

https://youtu.be/0-cEdwgYdAw?t=6m29s

 

A roll with the gear out app. 220°/s.

 

Edited July 15, 2016 by CoBlue

[Fri13]

Please add a video of the DCS Mig flying then so it can be compared.

[CoBlue]

Please add a video of the DCS Mig flying then so it can be compared.

I can't make videos.

It's very apparent in the sim how slow the roll rate is.

[Frederf]

DCS roll rate seems very AOA dependent. At 2°AOA it takes much longer than 0°AOA. From wings level at 1/16X speed it took me 53s to complete one roll which is 3.3125s real time.

 

I'm getting peak roll rates of 270-320°/s. I'm also able to snap roll from static wings level back around to wings level in about 2.1-2.6 seconds pretty reliably.

 

The video shows about a 2.0s 360 (7.9 at 1/4 speed) with a visible bunt for low AOA before the maneuver. I can manage about 9.0 (1/4th speed) a similar maneuver.

 

The DCS might be a little slow possibly in initial and final response as opposed to peak roll rate but the air show pilot is doing more tricks than the average sim pilot. It's definitely a maneuver using all 3 axes.

 

My process is bunt to UUA-1 1° (about zero AOA) simultaneous strong right rudder for about 1/8 turn. When (right) turn builds up to >90dps reverse rudder to full left. Stick pulls back from slight forward pressure to ~20% aft through inverted and then back to slight forward smoothly in the roll. In the last 1/8 of turn full left rudder and left stick to stop roll at wings level.

 

If DCS -21 is deficient in roll it's not by much. Slightly negative AOA combined with intelligent use of rudder results in very high roll authority.

[gavagai]

Mig-21 rolls like a fat cow in 1.5.4. The roll rate in 1.5.3 was comparable to the videos.

 

Just to be sure I played with the aileron boost switch to make sure it's working. The switch works, so the terrible roll is intended.:disgust:

 

I really hope something can be done to bring the old roll rate back. Pretty please?:sad_2:

[bkthunder]

I want whatever roll rate is the closest to the REAL aircraft's roll rate.

 

Now the point is, why is there such a huge difference between iterations of a flight model that should be in the "finishing touches" part of the development, and has been sold throughout as "realistic"?

 

Oh well... for now it stays in the hangar. I have no interest in flying something that might as well be a complete fantasy aircraft. I learn how to fly this thing, and the next patch it behaves in a very different way. I want a simulation, and I want to trust this simulation.

[Neuman]

I want whatever roll rate is the closest to the REAL aircraft's roll rate.

 

Now the point is, why is there such a huge difference between iterations of a flight model that should be in the "finishing touches" part of the development, and has been sold throughout as "realistic"?

 

Oh well... for now it stays in the hangar. I have no interest in flying something that might as well be a complete fantasy aircraft. I learn how to fly this thing, and the next patch it behaves in a very different way. I want a simulation, and I want to trust this simulation.

 

Do you Have nomograms "Roll rate at speed" or similar? Unfortunately In the flight manual for "Izdeliye 75" I couldn't find information about this.

[CoBlue]

If DCS -21 is deficient in roll it's not by much. Slightly negative AOA combined with intelligent use of rudder results in very high roll authority.

AFAIK as a general rule, you are not supposed to use rudder in a fighter jet in maneuvers, rudder is only used for cross-wind landings.....maybe I'm wrong, but that's what I've heard from many former military pilots I've flown with.

Using rudder to roll the Mig-21 sounds strange.

With it's short wingspan the 21 should roll much faster that it's doing right now. It's supposed to be agile.

I would certainly not call it "close to the real thing" as it is now & I can only achieve high roll authority past M1.0.

[gavagai]

AFAIK as a general rule, you are not supposed to use rudder in a fighter jet in maneuvers, rudder is only used for cross-wind landings.....maybe I'm wrong, but that's what I've heard from many former military pilots I've flown with.

 

You need a little bit of rudder when you turn the Mig-21 for the simple reason that the outside wing has a little more drag than the inside wing (same as every aircraft), and the old jet doesn't take care of that for you the way newer fighters do.

 

But for simply rolling the Mig-21 rudder is silly. It's not a WW1 scout. It's a delta-wing interceptor.:doh:

[Fri13]

AFAIK as a general rule, you are not supposed to use rudder in a fighter jet in maneuvers, rudder is only used for cross-wind landings.....maybe I'm wrong, but that's what I've heard from many former military pilots I've flown with.

 

I read from here the phrase "Step on the ball" or something about coordinated turns, so everytime when you are turning you should use leg on the side where the slip is going to get it on center etc.

 

Of course in combat maneuvers it can be different thing, but I don't see a reason why not to use it to create a slightly different slide?

[gavagai]

Rodd is correct. You don't use the rudder for BFM in a modern fighter.

 

http://www.f-16.net/forum/viewtopic.php?t=2119

 

Even for crosswind landings you don't touch the pedals in an F-16.

[BadHabit]

AFAIK as a general rule, you are not supposed to use rudder in a fighter jet in maneuvers, rudder is only used for cross-wind landings.....maybe I'm wrong, but that's what I've heard from many former military pilots I've flown with.

Using rudder to roll the Mig-21 sounds strange.

With it's short wingspan the 21 should roll much faster that it's doing right now. It's supposed to be agile.

I would certainly not call it "close to the real thing" as it is now & I can only achieve high roll authority past M1.0.

 

Terms like "your not supposed to" or "only used" , I don't get it..Most fighters now days use computing systems that calibrate the pilots inputs so yes they don't need to, propably cause the computers do those tiny adjustments. 2nd and 3rd generation fighters didn't had those helpers..Rudder is as important as any input in flight.

Most people don't really understand the use of the rudder either on prop ACs or Jet engine Acs, me included thas I started reading about it. Here is something that really helped me get the points http://www.empire-aviation.com/flight-instructors/john-e-mclain/understanding-the-use-of-rudder.html .

[CoBlue]

Terms like "your not supposed to" or "only used" , I don't get it..Most fighters now days use computing systems that calibrate the pilots inputs so yes they don't need to, propably cause the computers do those tiny adjustments. 2nd and 3rd generation fighters didn't had those helpers..Rudder is as important as any input in flight.

Most people don't really understand the use of the rudder either on prop ACs or Jet engine Acs, me included thas I started reading about it. Here is something that really helped me get the points http://www.empire-aviation.com/flight-instructors/john-e-mclain/understanding-the-use-of-rudder.html .

 

I do know the impotence of rudder.

http://forums.eagle.ru/showpost.php?p=2653189&postcount=81

Mig-21 with it's swept-wings is a different story, rudder is not as important in BFM.

Ok it probably needs some rudder if you fly a steady 20-40° bank, to stay coordinated.

Furthermore you linked article is about turns, not fast rolls.

 

Rodd is correct. You don't use the rudder for BFM in a modern fighter.

http://www.f-16.net/forum/viewtopic.php?t=2119

Even for crosswind landings you don't touch the pedals in an F-16.

 

Thanx! That was what I was looking for! I totally forgot about the swept-wings....;)

"More appropriatly, Most swept wing jets don't use rudder for turns. The amount of drag on the up wing is generally not enough to cause a noticeable adverse yaw. The F-16 does have automatic rudder compensation, but even other jets like the (A)T-38 don't use rudder to coordinate turns.

Rudder is not used in swept-wing fighter jets, you pull into a turn"

 

Can we please concentrate on the Mig-21's roll rate now!

Edited July 11, 2016 by CoBlue

[Frederf]

I can acheive 320dps roll rate and execute 360 rolls in 2s. Maybe it is a flight skills issue.

[gavagai]

Can we please concentrate on the Mig-21's roll rate now!

 

I'd like to add that at least half the scrutiny should be on the roll inertia, not just the maximum roll rate.

 

I can acheive 320dps roll rate and execute 360 rolls in 2s. Maybe it is a flight skills issue.

 

Indeed, the aileron roll is one of the most difficult maneuvers in the Mig-21bis. We'll have to post a good track or video on the proper technique.

[grunf]

It seems that even the slight amount of back pressure on the stick drastically reduces roll rate. I'm not sure it's suppose to work like this. I know the roll rate depends on the AoA, but it seems excessive.

[Wizard_03]

Yeah I think its just a matter of keeping the pitch neutral and proper rudder input. Because I can get a roll rate pretty close to the video in the OP if I use the rudder at the right time, and I wouldn't call myself an amazing pilot.

 

IMO I think the Adjustment to the FM in this respect is more accurate because if you look at the migs tiny lil ailerons and the massive rudder it kinda makes sense to me that you would need more then usual rudder input in rolls.

[CoBlue]

It seems that even the slight amount of back pressure on the stick drastically reduces roll rate. I'm not sure it's suppose to work like this. I know the roll rate depends on the AoA, but it seems excessive.

Correct.

AoA oscillations shouldn't be a factor for rolling the 21.

"Delta wing of MiG-21 with sweep of 57 º retains stable airflow to very high angles of attack"

 

Also remember we are talking about high speeds of 7-900km/h.

 

I would really like Dolphin887 to comment on this, as he's the FM coder for LN & an active Mig-21bis pilot.

Edited July 12, 2016 by CoBlue

[bkthunder]

 

I would really like Dolphin887 to comment on this, as he's the FM coder for LN & an active Mig-21bis pilot.

 

Exactly this! He can explain why the big differences in the various versions, and what is actually realistic.

 

P.s. From my very different experience in the Pitts S-2, the rudder is used in the roll, and the correct technique to achieve a graceful and fast roll is this: (in case of e.g. Left roll) Stick fully left > at the same time left rudder than right rudder for a moment, then left rudder again until level. Everything happens very fast in the Pitts, so the actual timing of the operation is almost exactly as saying "left-right-left". Absolutely no noticeable amount of pitch movement is used during the maneauver, and if you dare pushing the stick half-way through the roll, your head will bang on the canopy (yes, even with your seat belts well fastened). Anyway this is a completely different aircraft and I really don't think the Mig-21 should be flown like an aerobatic biplane.

[Frederf]

Manual talks about a roll achieved in 6-8s. Rapid rolls like we're exploiting sounds like "inertia rotation of aircraft" which they categorize as a hazardous condition.

[firmek]

Exactly this! He can explain why the big differences in the various versions, and what is actually realistic.

 

P.s. From my very different experience in the Pitts S-2, the rudder is used in the roll, and the correct technique to achieve a graceful and fast roll is this: (in case of e.g. Left roll) Stick fully left > at the same time left rudder than right rudder for a moment, then left rudder again until level. Everything happens very fast in the Pitts, so the actual timing of the operation is almost exactly as saying "left-right-left". Absolutely no noticeable amount of pitch movement is used during the maneauver, and if you dare pushing the stick half-way through the roll, your head will bang on the canopy (yes, even with your seat belts well fastened). Anyway this is a completely different aircraft and I really don't think the Mig-21 should be flown like an aerobatic biplane.

 

The question is how big - if any is the difference with more modern, delta wing but still not a fly-by-wire aircraft:

 

[ame]https://www.youtube.com/watch?v=bbDZIGcfKG0&feature=youtu.be&t=387[/ame]

 

(part related to the topic starts at 6:30)

 

It's an old but a great video.

[GGTharos]

I'm fairly confident that if you do this in a jet fighter you'll achieve a fairly unpleasant inertial roll coupling.

 

Exactly this! He can explain why the big differences in the various versions, and what is actually realistic.

 

P.s. From my very different experience in the Pitts S-2, the rudder is used in the roll, and the correct technique to achieve a graceful and fast roll is this: (in case of e.g. Left roll) Stick fully left > at the same time left rudder than right rudder for a moment, then left rudder again until level. Everything happens very fast in the Pitts, so the actual timing of the operation is almost exactly as saying "left-right-left". Absolutely no noticeable amount of pitch movement is used during the maneauver, and if you dare pushing the stick half-way through the roll, your head will bang on the canopy (yes, even with your seat belts well fastened). Anyway this is a completely different aircraft and I really don't think the Mig-21 should be flown like an aerobatic biplane.

[Hadwell]

The mig21 relies on radial G's for safe changes in direction, you need to see what direction the G's are pulling your plane, use that to roll into a corner, which is why you do rudder rolls, think of it as micro-yo-yos...

 

If your g loading is off, then it just feels wrong, sometimes just doing a full barrel roll fixes it... at least that's what I find...

 

If roll rates are supposed to be higher, I have no idea though...

[lunaticfringe]

Rodd is correct. You don't use the rudder for BFM in a modern fighter.

 

http://www.f-16.net/forum/viewtopic.php?t=2119

 

Even for crosswind landings you don't touch the pedals in an F-16.

 

You didn't actually call a pure linkage to hydraulically boosted control system "modern" in comparison to interpreted control surface commands in a FBW aircraft, did you?

 

Oh, you did.

 

Yeah, you might want to investigate flow separation at high AoA. Doesn't matter how "stable" the manual says it is- the natural effect of increasing AoA on wing-plane control surfaces (ie, ailerons) is degraded authority. Meanwhile, as flow is maintained out of that region, rudder authority is increased, and depending on the aircraft, roll axis instability can occur.

 

Thus, you invoke pedal to initiate and control roll, with increasing input as AoA increases.

 

As to comparing an F-16 to a MiG-21's control methodology, they have no basis from which to start. There is no input issued by the pilot- either through stick, or pedal, that is not interpreted across multiple channels and then directed to the control surfaces. And the Viper can use them all- including the rudder, to do what the system believes the pilot is looking for. Tap the stick to the side with enough AoA on the airframe, and it will indeed induce rudder, just like any other FBW aircraft, in the attempt to maximize instantaneous performance on an axis.

 

The Fishbed has no such interpolation. Subsequently, stating that a pilot flying an FBW aircraft doesn't use the pedals isn't indicative of what a MiG-21 pilot must do- the Viper driver doesn't hit the pedals to roll because the airplane already knows it needs to use the rudder.

Edited July 13, 2016 by lunaticfringe

[GGTharos]

Besides, it's all BS. Pilots use the rudder in BFM - it just depends on the fight itself - ie. lots of AoA = rudder coming into play.