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Help keeping the nose up during high bank angle maneuvers


SPS48A
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I'm trying to fly the Thunderbird's solo routine in the F16 and I am really struggling keeping the nose up during high bank angle maneuvers. I keep losing altitude, gaining altitude, or crashing when performing:

 

Slow rolls

4 or 8 point rolls

knife edge pass

max rate circles

any turn with bank angles greater than 60 degrees.

 

I try using the rudder to keep the nose up but I end up crashing or at best widely off my starting altitude. To keep from hitting the ground in a high speed circle turn I find myself reducing bank angle periodically and nosing back up and then increasing bank angle again. Doesn't look all that smooth or good.

 

Anyone have any suggestions on how to manage the nose angle in high bank or roll maneuvers.

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Hi!

Confirmed.

In DCS (latest OB version) knife edge pass requires more than 800KIAS (which is obviously wrong).

For info, it was less than 800KIAS on the last time I tried the Stable (something about 600-700KIAS IIRC, better, but still wrong. It should be much less than this).

We have FM issue and/or FLCS (rudder authority) issues here.

(Note that roll behavior is wrong also.)

Regards.


Edited by Dee-Jay
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What he tries to say is that currently you have not enough Rudder Authority to keep the Plane stable. Except if you are very fast as Dee-Jay has confirmed.

Which i can confirm also.

 

The Gs are not the Problem in that case.

 

Well this Plane has a long way to go until its finished, so developing an Hind seems to be a good idea now. What can go possibly wrong if you distribute the Devs even more?

Otherwise we would be in Danger that the F-16 or F-18 gets completet which is something we should strictly avoid as it seems..... :mad:

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dunno what i'm doing wrong or simply don't understand OP test, but on my side, i was able to fly between 550-600 KIAS, straight, no turnings, so 1g or slight pression on the stick for 1.5g-2g or so, at 60-70 deg bank angle, without loosing altitude, i tried to turn for about a few minutes in circles, going from 350 kias to 600 kias+ altering g's from 2 to 5-6+ without loosing altitude between 60 to almost 90 deg bank. Got to say i was using rudders though. I made my test between 720-740 ft Using OB with latest patch.

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I'm trying to fly the Thunderbird's solo routine in the F16 and I am really struggling keeping the nose up during high bank angle maneuvers. I keep losing altitude, gaining altitude, or crashing when performing:

 

Slow rolls

4 or 8 point rolls

knife edge pass

max rate circles

any turn with bank angles greater than 60 degrees.

 

I try using the rudder to keep the nose up but I end up crashing or at best widely off my starting altitude. To keep from hitting the ground in a high speed circle turn I find myself reducing bank angle periodically and nosing back up and then increasing bank angle again. Doesn't look all that smooth or good.

 

Anyone have any suggestions on how to manage the nose angle in high bank or roll maneuvers.

 

Go to E-publishing.af.mil, look for the AFI 11-246V1. That is the USAF demonstration instruction and there are no releasability restrictions on this publication. All the maneuvers will describe there including aircraft configuration.

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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What he tries to say is that currently you have not enough Rudder Authority to keep the Plane stable. Except if you are very fast as Dee-Jay has confirmed.

Which i can confirm also.

 

The way the Knife edge pass is describe in the USAF instruction, it is suppose to loose altitude.

For example:AFI 11-246V1, page 110, para 5.20.2

If it becomes apparent the aircraft may descend below 400 feet AGL, roll out of the bank and clear the show line.

If it is normal to maintain altitude with rudder during the knife edge pass, why add this notice?

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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Because at key point you may not have the required speed. So, rather than aborting the pass, you can accept a bit of altitude loss.

 

I will try to retrieve a HUD tape I've seen recently showing a Thunderbird knife edge pass at high altitude (with no altitude loss). IIRC, it was a video of a German flying in backseat.

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FWIW although from a crowd perspective a knife may look flat, the knife edge isn't flat from the cockpit, you will need 5-7° of pitch at the start of the maneuver. So you're arcing the pass from one side to the other. However, there is a lack of rudder authority in the ED Viper.

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So I understand:

Minimum speed entry is 400KCAS or 674 feet per second. Minimum altitude entry is 400 feet AGL.

The knife edge pass should be 8000 feet long, so it should take 12 seconds. You have to raise the nose 5 to 7 degrees, establish a climb before banking the aircraft 90º. If it becomes apparent the aircraft may descend below 400 feet AGL: abort, but it should not loose altitude.

 

Is that what we are saying?

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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This is an old post. I remember reading this OP when I was a teenager... in a certain old Falcon game...

 

Hey I did a pretty accurate video of a solo AF Demo:

 

Knife edge is at about 10:35

but you're not gonna get perfectly lvl flight. Demo pilots usually either do it with the wings perfectly vertically or sometimes with an angle (110 degrees bank angle) to get the aircraft perfectly lvl. In my demo I kind of combined the 2 techniques. But the idea is that you go past 90 degrees to use forward pitch to undo the loss in attitude.

(you can see my inputs on this matter)

 

But I had no problems doing all the maneauvers as described in the USAF AFI 11-246

...Maybe I had some problems doing them right, but....


Edited by Theodore42
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This is an old post. I remember reading this OP when I was a teenager... in a certain old Falcon game...

 

Hey I did a pretty accurate video of a solo AF Demo:

 

Knife edge is at about 10:35

but you're not gonna get perfectly lvl flight. Demo pilots usually either do it with the wings perfectly vertically or sometimes with an angle (110 degrees bank angle) to get the aircraft perfectly lvl. In my demo I kind of combined the 2 techniques. But the idea is that you go past 90 degrees to use forward pitch to undo the loss in attitude.

(you can see my inputs on this matter)

 

But I had no problems doing all the maneauvers as described in the USAF AFI 11-246

...Maybe I had some problems doing them right, but....

 

Don't know if you were suggesting it is my old post, but it is not. Never the less, thanks for that video. Very cool. You obviously have better command of the Viper than I do. Thanks for the demo. Very nice! During the knife edge, did you depend on rudder at all, didn't seem to be much if any. Again, thanks for posting the video.

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Go to E-publishing.af.mil, look for the AFI 11-246V1. That is the USAF demonstration instruction and there are no releasability restrictions on this publication. All the maneuvers will describe there including aircraft configuration.

 

Thanks for that document. Part of the problem is not enough speed and obviously not enough practice. I wasn't watching speed that closely but it seems I was trying to do them around 300-350K. I will try to follow the document more closely. Thanks again.

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Don't know if you were suggesting it is my old post, but it is not.

Nah, I mean way back in the early 2000s was when I was a teenager and this was an OP on the forums of the first serious study sim of an F-16. Just funny to see this topic come up again.

 

For the record, DCS F-16 is much better :)

 

BTW I had a lot of fun following the descriptions of the maneuvers in the manual.

To experience the same effects described in an actual demo manual :thumbup:

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Okay ... so here we go, Knife edge pass:

 

Entry at 450KCAS, altitude level about 6600ft during 10s @ 470 - 480KCAS (could be longer as you see "pitch" attitude remains stable):

 

We don't see much there:

 

...

 

Now in DCS, clean configuration, about 3000LBS fuel.

 

I can't maintain altitude level:

 

Second attempt a bit faster, not better:

?t=37

 

Slow roll ... unable to do it correctly and not the bug on yaw resonance/LCO:

?t=116

 

 

2nd slow roll attempt, yaw oscillation are even worse. I can't complete the maneuver:

?t=138

 

Descending NOE to increase aero pressure as mush as possible, accelerating up to 850KCAS, still no good:

?t=227

 

Then 880 - 890KCAS, Knif edge pass is "okayish", but we are way am above max airspeed.

 

(Not on the video and unfortunately, I failed to record the track, but I've also noted a serious bug on engine shutdown ... RMP below 20%, Throttle back to Idle, engine restart by its own without JFS! That would be a very safe engine IRL! ... but that doesn't exit. ;) FTIT goes off scale, no engine damage.)

...

 

I do even feel that it was somehow a little bit better on the Stable on October 2019 (almost one year ago):

 

Regards.


Edited by Dee-Jay
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Is problem that rudder doesn't have authority to achieve that beta angle for knife edge flight or that at certain beta side load lift isn't enough?

 

Yes.

This is what you would be going for in DCS:

 

The F-16 can't produce enough lift with its rudder alone to perform a perfectly level Knife-Edge Pass. To overcome this, the pilot must pass the 90 degree mark and then pitch forward to maintain level flight. Also note that the FPM is not visible in the HUD during the maneuver. The pilot must maintain level flight with the Vertical Velocity Indicator, or VVI tape (to the right of the artificial horizon on the instrument panel).

In other words, the pilot must memorize the correct inputs and then use The Force .

 

Although the manual says to do the knife edge at 90 degrees:

 

5.20.1. Maneuver Description: Enter the 1,500’ show line at 500 feet AGL and 425 knots.

At 4,000 feet prior to show center, raise the nose to five to seven degrees, establish a climb,

and apply stick pressure to roll 90 degrees toward the crowd. Hold this attitude until 4,000

feet past show center. Use top rudder to hold the nose above the horizon and forward stick

pressure to keep the aircraft on the show line. To complete the maneuver, unload, roll wingslevel, and perform a repositioning maneuver.


Edited by Theodore42
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