"Pedal turn" versus "Conventional turn"

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quicksilver

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Unread post03 Jan 2019, 16:05

gta4 wrote:My takeaway:

1) horizontal pirouette = pedal turn.

2) vertical pirouette = J turn
https://www.youtube.com/watch?v=NQv5IZqndTY

Haha never though super bug could reverse heading that fast.


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Unread post03 Jan 2019, 21:10

Just some quotes wot I picked out however there are many more but youse can find them ye-selves I think. Thanks to OP.

Super Hornet Total Flight Control Systems Integration Process 2000 p011127 pp12.pdf (1.5Mb)

download/file.php?id=29246 (PDF 1.5Mb)
Operational Lessons Learned from the F/A-18E/F Total Flight Control Systems Integration Process
8-11 May 2000 Mr. Robert J. Hanley; Commander David A. Dunaway [USN]; Mr. Kenneth P. Lawson

"...OPERATIONAL EVALUATION (OPEVAL)…
...In addition to the impressive pitch pointing and departure resistance of the Super Hornet, there are several performance characteristics at high AOA that will allow the Super Hornet to dominate the engaged maneuvering environment. During early operational tests, the inability to generate yaw rates at angles of attack above 25 degrees was identified as a major limitation to air to air combat. At that time, the use of sideslip and sideslip rate feedback to prevent departures had also limited the maneuverability of the airplane to an unacceptable level. Through an aggressive process of design and close interface with the operational community, the flight control logic was modified to allow proverse sideslip within a specific AOA and airspeed range. This change did not decrease departure resistance but significantly improved the ability of the Super Hornet to rapidly reposition the nose from a nose high to a nose low position. In addition to impressive pitch pointing, the Super Hornet has the combined roll/yaw axis to use in quickening the transition from nose high to nose low conditions. This maneuver is akin to the pirouette maneuver performed by the heritage Hornet with the notable exception of precise control. In the case of the heritage Hornet, the pirouette is essentially a controlled departure that quickly transitions the aircraft from nose high to nose low. Once the maneuver is initiated, the pilot is essentially along for the ride. By contrast, in the Super Hornet, the maneuver can be performed with good control throughout. In fact, the F/A-18E/F is easily transitioned from a pirouette to a precise guns tracking solution at virtually any point in the maneuver. A precipitous byproduct of the Super Hornet pirouette maneuver is an impressive horizontal plane maneuver that generates tum rates similar to maximum instantaneous tum rates but at airspeeds less than 150 knots. The maneuver is performed at full aft stick stall by invoking the pirouette maneuver for 2-3 seconds from a tum or level flight. Once initiated, the aircraft roll/yaws through 40-60 degrees of tum at which point the pirouette control inputs are removed and the aircraft is recovered back to level flight. This maneuver can be repeated in sequence to create an impressive "effective" instantaneous tum rate. This maneuver is frequently used as a secondary threatening maneuver after the pilot has used the impressive pitch pointing for a first shot advantage.

In summary, there is no single maneuvering characteristic that makes the F/A-18E/F an effective maneuvering platform. It is the synergy enjoyed by combining the effective pitch rate, pilot confidence that comes from departure resistance, high AOA maneuverability, pirouette, and deck transition. Although Air Combat Maneuvering (ACM) is usually avoided as much as possible and only used as a last resort, it is an excellent benchmark of maneuverability. The Super Hornet has proven to be an impressive ACM platform. Pilots have found that the Super Hornet is most effective when using an aggressive position fight. The pitch pointing provides the first shot capability, the departure resistance and high AOA maneuvering allows the Super Hornet to maintain the threatening position and lastly, the pirouette/deck transition allow the Super Hornet to achieve quick follow up shots. For a conventionally designed aircraft with relatively low thrust to weight ratio, the Super Hornet is one of the premier ACM aircraft available today....

...LESSONS LEARNED
Some important lessons learned from the Super Hornet development include:...

...5. Wing design is still an art. Prediction of "wing drop" like phenomenon is still a "black art". Hopefully, the National AWS program will shed new light on this topic.

6. As more aircraft are able to exploit the high AOA region, new tactics will have to be developed. These tactics must be analyzed to determine exactly what kind of rates are necessary to be lethal in this environment without undue penalty to the airplane design in other areas (again, everything is a trade). To date, even with HANG and HAIRRY, it has been difficult to pin down critical design guidelines for high AOA tactical utility.

7. Regardless of how sophisticated, a FCS can do nothing without control power.

8. Designer engineers must realize that what they think is important is not always what a pilot thinks is important. Case in point, if the engineers think it is a great idea to design an airplane to be flown with "reckless" abandon by providing superior departure resistance in the flight control system automatically, they may actually (and probably will be) taking away some of the tactical utility of the aircraft. There was (and is) a lot of truth to the fighter pilots view of the world that you have to fly "to the edge of the envelope", the point just prior to a departure, in order to maximize the effectiveness of your aircraft in combat. As shown in the F/A-18E/F and the initial inability to perform a pirouette maneuver, too much artificial departure resistance inhibits the pilot from tapping into the maximum capability of the aircraft. There comes a point where you have to let the pilot judge where and how to use the edge of the envelope vice the engineer and the DepRes type system.

9. And lastly, the team wanted to eliminate the time consuming process of modifying flight control laws, which plagued the F/A-18A/B development. This was done by incorporating a "dial-a-gain" function in the test aircraft that would allow for limited changes to control laws in order to optimize the existing OFP more efficiently rather than having to produce a new OFP every time a small gain change had to be made. The F/A-18A/B had over 110 OFP changes, over 70 of which flew on the test aircraft. In contrast, the F/A- 18E/F had less than 10 OFP changes."

Source: http://www.dtic.mil/dtic/tr/fulltext/u2/p011127.pdf [attached 'text readable' PDF on previous page & above]
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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Unread post04 Jan 2019, 05:20

https://youtu.be/Nf5A13atLHQ

Just in case you all were thinking only the SH could pull off spectacular maneuvers. I saw this video last year and was floored, never have I seen such maneuverability from a legacy Hornet. I've seen many shows and F-18 demos and it is nearly as spectacular as the SH. I was able to chat with a legacy F-18 pilot and was informed Hornets have flown like this from the beginning. Asked why we in the states were not privileged to see this demo, the Brass, made that call.
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Unread post04 Jan 2019, 06:26

gta4 wrote:http://www.f-16.net/forum/viewtopic.php?f=22&t=52907

Now we know the "pedal turn", is a high yaw rate maneuver, not a conventional turn. So it is neither sustained turn, nor instantaneous turn. However, since the angular velocity (28 deg/sec) is constant, pedal turn is equivalent to a sustained turn of 28 deg/sec, because it changes its heading at a steady 28deg/sec, and an enemy fighter could not counter it unless it performs a sustained 28deg/sec turn (conventionally or yawing).

Is this understanding correct?


It was a feature of the F16 AFTI and also that the reversed arrow of the X29 could provide given that yaw on the latter would mean the wing inside the turn would get all the lift and flex upward also. Not sure why neither were further pursued, maybe too advanced.
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Unread post04 Jan 2019, 07:22

strykerxo wrote:https://youtu.be/Nf5A13atLHQ

Just in case you all were thinking only the SH could pull off spectacular maneuvers. I saw this video last year and was floored, never have I seen such maneuverability from a legacy Hornet. I've seen many shows and F-18 demos and it is nearly as spectacular as the SH. I was able to chat with a legacy F-18 pilot and was informed Hornets have flown like this from the beginning. Asked why we in the states were not privileged to see this demo, the Brass, made that call.

:doh: it is not Asif we have not seen THIS Video before - search the forum using the string Nf5A13atLHQ and yous'll get 12 hits not counting this one above today. Jeepers we get it - the SWISS Hornet is YOU BEAUTEH - we remember SION 2017.

search.php?keywords=Nf5A13atLHQ&terms=all&author=&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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Unread post04 Jan 2019, 08:17

strykerxo wrote:https://youtu.be/Nf5A13atLHQ

Just in case you all were thinking only the SH could pull off spectacular maneuvers. I saw this video last year and was floored, never have I seen such maneuverability from a legacy Hornet. I've seen many shows and F-18 demos and it is nearly as spectacular as the SH. I was able to chat with a legacy F-18 pilot and was informed Hornets have flown like this from the beginning. Asked why we in the states were not privileged to see this demo, the Brass, made that call.


Actually legacy Hornet flight control software has been upgraded about 15 years ago to allow many of the same maneuvers that SH could pull off. Interestingly this whole upgrade was proposed that exact same year that the "Operational Lessons Learned from the F/A-18E/F Total Flight Control Systems Integration Process" Spaz posted earlier was released. Probably someone realized that the same things could be done with legacy Hornets by simply upgrading software. Pretty damn impressive that all this could be done with only improving FCC software!

https://ocw.mit.edu/courses/aeronautics ... _brief.pdf

Need to upgrade the FCC software
– Mishap Prevention
• Suppress out of control flight modes
• Improve departure resistance
– Improve maneuverability at high AOA
• Improve roll performance above 30° AOA
• Implement “Pirouette” Feature


Some other intresting files like more detailed info about Hornet flight control software development can be found in the same directory:
https://ocw.mit.edu/courses/aeronautics ... ure-notes/
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Unread post04 Jan 2019, 09:40

hornetfinn wrote:
strykerxo wrote:https://youtu.be/Nf5A13atLHQ

Just in case you all were thinking only the SH could pull off spectacular maneuvers. I saw this video last year and was floored, never have I seen such maneuverability from a legacy Hornet. I've seen many shows and F-18 demos and it is nearly as spectacular as the SH. I was able to chat with a legacy F-18 pilot and was informed Hornets have flown like this from the beginning. Asked why we in the states were not privileged to see this demo, the Brass, made that call.


Actually legacy Hornet flight control software has been upgraded about 15 years ago to allow many of the same maneuvers that SH could pull off. Interestingly this whole upgrade was proposed that exact same year that the "Operational Lessons Learned from the F/A-18E/F Total Flight Control Systems Integration Process" Spaz posted earlier was released. Probably someone realized that the same things could be done with legacy Hornets by simply upgrading software. Pretty damn impressive that all this could be done with only improving FCC software!

https://ocw.mit.edu/courses/aeronautics ... _brief.pdf

Need to upgrade the FCC software
– Mishap Prevention
• Suppress out of control flight modes
• Improve departure resistance
– Improve maneuverability at high AOA
• Improve roll performance above 30° AOA
• Implement “Pirouette” Feature


Some other intresting files like more detailed info about Hornet flight control software development can be found in the same directory:
https://ocw.mit.edu/courses/aeronautics ... ure-notes/


I think it was in hushkit or foxtrot alpha, the Navy pilot explaining that the legacy Hornet being smaller and lighter is a bit more nimble than the super hornet, with greater sustained rate of turns
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Unread post04 Jan 2019, 10:34

boilermaker wrote:I think it was in hushkit or foxtrot alpha, the Navy pilot explaining that the legacy Hornet being smaller and lighter is a bit more nimble than the super hornet, with greater sustained rate of turns


I agree with this and the big motor legacy Hornet (like the Swiss one in the video) also has better T/W ratio especially when lightly loaded. I think big motor legacy Hornet (C/D) is very underrated fighter aircraft that actually had and still has (for 4th gen fighter) very good all-around performance with the latest software and updates.
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Unread post04 Jan 2019, 14:05

gta4 wrote:However, since the angular velocity (28 deg/sec) is constant, pedal turn is equivalent to a sustained turn of 28 deg/sec, because it changes its heading at a steady 28deg/sec, and an enemy fighter could not counter it unless it performs a sustained 28deg/sec turn (conventionally or yawing).

Is this understanding correct?

I'm not gonna (again) explain why, but I want to object that this is patently not how it works.
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Unread post04 Jan 2019, 15:31

lbk000 wrote:
gta4 wrote:However, since the angular velocity (28 deg/sec) is constant, pedal turn is equivalent to a sustained turn of 28 deg/sec, because it changes its heading at a steady 28deg/sec, and an enemy fighter could not counter it unless it performs a sustained 28deg/sec turn (conventionally or yawing).

Is this understanding correct?

I'm not gonna (again) explain why, but I want to object that this is patently not how it works.


Well this was my old post and now I know why, especially after I read about how F-15/16 defeated X-31 in Sep 1994. That was an epic battle. X-31 already had helmet mounted sight in its inventory, but F-15/16 had enormous energy in the vertical and created an altitude sanctuary (source: X-31 flying beyond the stall. https://www.nasa.gov/sites/default/file ... _Stall.pdf). The mighty X-31 used to own USN F-14D/18C with serious exchange ratio advantage, however after pitting against F-15/16, X-31 found a tough counter.

Honestly X-31 is a lot more maneuverable than Su-27 and Mig-29s (variants of 1990s era), I guess that is why Russian 4th Gen did not cause big panic in western world, as opposed to Russian propaganda.

This is why I am interested in climb rate and acceleration, in addition to nose pointing capability. I think F/A-18E/F a good ACM platform not only for its nose authority, but also for its good subsonic acceleration (slightly better than Su-27SK below 550 kts). If you check my previous post there was an estimation of F-35A's acceleration.
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Unread post04 Jan 2019, 17:19

Yeah sorry I did go back to see the timestamp for the quoted text. Figures that's what happens when I check forums right after I wake up.
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Unread post04 Jan 2019, 20:02

One of my instructors taught me how to fly using nothing more than pedal turns and elevator trim tab.

From take off to lining up for final, I have flown entire sorties (except for landing) with nothing but pedals and trim tab.

Once you hit the pedal, the difference in wing speed causes one wing to lose lift, the other to gain lift, and then you are in a banked turn. Don't ask me about if it's coordinated or not because I don't ever recall looking at gauges.

I recommend any pilots here on this forum to give it a shot. Of course we're talking about a trainer and not a Tomcat but I bet the Tomcat would have been a blast for that.
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Unread post04 Jan 2019, 20:15

"Well this was my old post and now I know why, especially after I read about how F-15/16 defeated X-31 in Sep 1994. That was an epic battle." (my emphasis added)

Use of the currently popular term 'epic' suggests a drama that, apart from an IFE, largely does not exist in flight test. The quote below from the NASA doc is germane.

"Evaluating handling qualities during close-in combat is particularly challenging because it is a very dynamic environment where angle of attack is constantly (and considerably) changing. X-31 testers therefore sought a more structured type of flight test to validate the subjective judgments of good handling qualities that were reached during the close-in-combat tests."
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Unread post05 Jan 2019, 00:18

crosshairs wrote:One of my instructors taught me how to fly using nothing more than pedal turns and elevator trim tab.

From take off to lining up for final, I have flown entire sorties (except for landing) with nothing but pedals and trim tab.

Once you hit the pedal, the difference in wing speed causes one wing to lose lift, the other to gain lift, and then you are in a banked turn.

Well yes, it is completely possible to fly with only the rudder in gentle flight regimes. Simple rudder-only R/C model aircraft have existed for a long time... the pedal turn relevant to this conversation is a leap beyond the rudder turn you're talking about. Since the effect of the rudder changes from yaw to roll as AoA increases, the "trick" here is just the opposite to what allows your rudder turn to work; at high AoA, the control laws need to prevent the rudder from rolling the aircraft and instead generate pure yaw authority.
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Unread post05 Jan 2019, 06:44

hornetfinn wrote:
boilermaker wrote:I think it was in hushkit or foxtrot alpha, the Navy pilot explaining that the legacy Hornet being smaller and lighter is a bit more nimble than the super hornet, with greater sustained rate of turns


I agree with this and the big motor legacy Hornet (like the Swiss one in the video) also has better T/W ratio especially when lightly loaded. I think big motor legacy Hornet (C/D) is very underrated fighter aircraft that actually had and still has (for 4th gen fighter) very good all-around performance with the latest software and updates.


Thanks Hornetfinn, makes me wonder how the YF-17 or F-18L might have handled, had the FCS been available at the time since they were several thousands of pounds lighter without the carrier requirement.

With handling like that, short of TV, the Hornet would be hard to outclass WVR. It also explains why the Western fighters have not pursued TV and the Russians use it as there only selling point. Does the F-16 have similar characteristics that we haven't seen?
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