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Next F-14 video by MagzTV


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It really depends on the circumstances, but yes, I reckon that a pilot can survive 21G for a short time (which the airframe cannot, at least not undamaged). To put it in perspective: Formula 1 driver Fernando Alonso survived a 305 km/h crash which peaked at 46G. He walked away with minor injuries.

 

Indycar driver Kenny Bräck survived a 214G (!!) crash. That's the highest recorded g-force since the introduction of crash violence recording systems.

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Can a human being survive 21g?

 

Is pulling that amount of g in the F-14 even remotely realistic in any circumstance or is this one of those issues where a PC joystick is acting like a fly by wire input and commanding unrealistic amounts of input compared to the real thing?

 

 

Recommend fast forward to 0;35....

 

What is it like to Pull 43 G's and 83 G's - History Channel

 

 

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It really depends on the circumstances, but yes, I reckon that a pilot can survive 21G for a short time (which the airframe cannot, at least not undamaged). To put it in perspective: Formula 1 driver Fernando Alonso survived a 305 km/h crash which peaked at 46G. He walked away with minor injuries.

 

Indycar driver Kenny Bräck survived a 214G (!!) crash. That's the highest recorded g-force since the introduction of crash violence recording systems.

 

Rapid onset / rapid decay is a different animal than sustained though.

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The different videos are approaching handling in different ways. Ralfi and Jabbers are comparing more directly to other modern DCS offerings and were rather surprised that their standard techniques for ACM were not working well in the F-14. The onset of roll reversal requires the virtual pilot to stop using lateral stick for roll, but the pilot also has to monitor where they are in the AOA range to know when to make this transition along with managing overall performance.

 

 

 

Magz was approaching handling from a more general perspective and much of what he was comparing to are WWII warbirds in terms of stability. :) Compared to a platform like that, the F-14 is very stable and will not drop a wing or develop any sudden uncommanded movements as you push to very high AOA. Once AOA goes above 20 or so, any sideslip may result in wing rock (not easy to track a target with wing rock), but the aircraft won't slice or roll off in this regimen. As AOA increases above 25-30 units, there is a tendency to roll off that may need rudder inputs for correction (not lateral stick!), but you can push the F-14 to very high AOA despite no FBW with excellent controllability.

 

 

 

This was one of the major breakthroughs for the F-14 versus older platforms when it first arrived, it allowed pilots to really push AOA to very high levels while still maintaining controllability and not departing. Part of this was related to the wing rock - the wing rock stabilizes the aircraft as it moves into negative yaw stability at high AOA due to adverse yaw with roll. As sideslip develops dihedral effect of the airframe induces roll, but because that initial roll causes the nose to yaw away from the direction of roll it pushes the nose back to center.

 

 

 

Where the F-14 starts to develop wing rock, the Phantom was prone to departure (roll off for the slatted F-4s and yaw off for the unslatted). So with pure pitch inputs, its hard to get into trouble with the F-14 (like nearly all the jets in DCS). However, you can get into trouble with poorly chosen inputs (like Ralfi and Jabbers described/demonstrated).

 

 

 

So if you give lateral stick above 20 units, you get roll opposite stick along with sideslip and the potential to develop yaw rate. If you hold that lateral stick past about 90-120 degrees of roll the yaw rate becomes pretty visible and could lead to a real departure. Similarly, you use rudder for rolling at ~17+ units AOA, but the roll SAS will cross-control your rudder inputs since it only monitors stick inputs for whether roll is "commanded". If you rudder roll with roll SAS on, most the time it is fine, but every so often it will cross control and create a significant yaw moment.

 

 

 

And at high AOA, you do did not monitor for excessive yaw rates in general, but things tend not to come out of no where.

 

 

 

So the F-14 is very hands on imho, but most of the dangerous things are due to bad pilot inputs not the aircraft deciding to take a swing at you. :)

 

 

 

-Nick

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21g is in the ballpark of an ejection seat bailout - so yes, it is surviveable, though sometimes with injuries.

 

Also depends on the direction. One can sustain more gees forward/backward/sideways than up and especially down. That's why the Heinkel Lerche draft had the pilot laying on his belly in forward flight for example. That just bucks if you want to look up then to follow a bandit in dogfights rdlaugh.png

 

So pulling 21G in a turn is a lot more stress to the body than accelerating or decelerating 21G in a plane with common seat arrangement.

 

Ejections have a very high risk of breaking the vertebrae. Interestingly the discogenics hardly suffer from that, but they tend to break easily after a few decades by just "living" (most commonly by just doing one's job, either too much or too little sports)... rainbowdashwink.png

dcsdashie-hb-ed.jpg

 

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The different videos are approaching handling in different ways. Ralfi and Jabbers are comparing more directly to other modern DCS offerings and were rather surprised that their standard techniques for ACM were not working well in the F-14. The onset of roll reversal requires the virtual pilot to stop using lateral stick for roll, but the pilot also has to monitor where they are in the AOA range to know when to make this transition along with managing overall performance.

 

Magz was approaching handling from a more general perspective and much of what he was comparing to are WWII warbirds in terms of stability. :) Compared to a platform like that, the F-14 is very stable and will not drop a wing or develop any sudden uncommanded movements as you push to very high AOA. Once AOA goes above 20 or so, any sideslip may result in wing rock (not easy to track a target with wing rock), but the aircraft won't slice or roll off in this regimen. As AOA increases above 25-30 units, there is a tendency to roll off that may need rudder inputs for correction (not lateral stick!), but you can push the F-14 to very high AOA despite no FBW with excellent controllability.

 

This was one of the major breakthroughs for the F-14 versus older platforms when it first arrived, it allowed pilots to really push AOA to very high levels while still maintaining controllability and not departing. Part of this was related to the wing rock - the wing rock stabilizes the aircraft as it moves into negative yaw stability at high AOA due to adverse yaw with roll. As sideslip develops dihedral effect of the airframe induces roll, but because that initial roll causes the nose to yaw away from the direction of roll it pushes the nose back to center.

 

Where the F-14 starts to develop wing rock, the Phantom was prone to departure (roll off for the slatted F-4s and yaw off for the unslatted). So with pure pitch inputs, its hard to get into trouble with the F-14 (like nearly all the jets in DCS). However, you can get into trouble with poorly chosen inputs (like Ralfi and Jabbers described/demonstrated).

 

So if you give lateral stick above 20 units, you get roll opposite stick along with sideslip and the potential to develop yaw rate. If you hold that lateral stick past about 90-120 degrees of roll the yaw rate becomes pretty visible and could lead to a real departure. Similarly, you use rudder for rolling at ~17+ units AOA, but the roll SAS will cross-control your rudder inputs since it only monitors stick inputs for whether roll is "commanded". If you rudder roll with roll SAS on, most the time it is fine, but every so often it will cross control and create a significant yaw moment.

 

And at high AOA, you do did not monitor for excessive yaw rates in general, but things tend not to come out of no where.

 

So the F-14 is very hands on imho, but most of the dangerous things are due to bad pilot inputs not the aircraft deciding to take a swing at you. :)

 

-Nick

Thank you for this, very well stated!

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The over-G thing concerns me. It'd be nice to have some form of artificial damping on the controls - at least to compensate for the fact that there's no arsefeel or feedback from a lot of joysticks. Something of an anti-frustration feature. That's one of the strengths of the Bug - it makes up for the inherent hamfist of a rough stick.

 

 

 

I've over-G'd mustangs pulling out of dive attacks simply because the game decided to momentarily pause while the damage to the enemy occured, then read my control input which held for the entire pause - wheras the exact same pull on three runs of the same mission had no effect.

 

 

 

Then again, I'm playing with an Xbox controller rather than a stick at the moment. If it's not my car consuming my cash, it's something else like putting fuel in my car, or driving long distance in my car, and getting 20mpg in my car - and those're european gallons.

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Agreed about the pilot's superhuman ability to pull on the stick hard enough to get g-forces so high. It's something that needs looking at in DCS in general, so the F-14 works well for how DCS is currently in that respect.

 

Loved the MiG-28 easter egg. Got me thinking if Jester would ever call an F-5 an F-5, but having now seen the discussion about the callouts corresponding to the skin I am impressed!

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As far as the F-14, has somebody gloc'd and pulled 21g's in it before?

 

No.. People who design control systems for aircraft like this try and make over stressing the aircraft quite difficult. This is usually done by an increasing Stick force per G amount, meaning that to pull the aircraft beyond its structural limits requires huge stick forces for the pilot.

 

From the Natops : "Artificial feel devices in the control system provide the pilot with force cues and feedback. A spring−loaded cam and roller assembly produces breakout force when the stick is displaced from neutral trim and provides increasing stick forces proportional to control stick displacement. Control stick forces, proportional to normal acceleration (g forces) and pitch acceleration are produced by fore and aft bob weights. Aircraft overstresses from abrupt stick inputs are minimized by an eddy current damper that resists large, rapid control deflections."

 

Regarding the flight regime of the F-14. I know that Dale Snodgrass was told to display the aircraft as a 9G jet but it would of course be very lightly loaded for airshow work.


Edited by Deano87

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Agreed about the pilot's superhuman ability to pull on the stick hard enough to get g-forces so high. It's something that needs looking at in DCS in general, so the F-14 works well for how DCS is currently in that respect.

 

This exactly is one of the main problems of pretty much any (combat) flight sim until now. Have been proposing some kind of strength, endurance and fatigue modeling (basically something that can be found in many RPGs, but more sophisticated) already for one well known WW2 sim in the past because of the turn'n'burnishness that one encountered there anywhere. People literally kept staying at 4+Gs nonstop for hours, racking up kills against those who weren't good enough at BnZing in their crates that turned worse than their adversaries.

 

This however is something that ED needs to bring to us. Having it just in a few modules made by a single dev team would limit their modules to the disadvantage over others even though it'd be more realistic.

 

And no matter how great FFB sticks are, they wouldn't limit pulling too much either rainbowdashwink.png

dcsdashie-hb-ed.jpg

 

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This exactly is one of the main problems of pretty much any (combat) flight sim until now. Have been proposing some kind of strength, endurance and fatigue modeling (basically something that can be found in many RPGs, but more sophisticated) already for one well known WW2 sim in the past because of the turn'n'burnishness that one encountered there anywhere. People literally kept staying at 4+Gs nonstop for hours, racking up kills against those who weren't good enough at BnZing in their crates that turned worse than their adversaries.

 

This however is something that ED needs to bring to us. Having it just in a few modules made by a single dev team would limit their modules to the disadvantage over others even though it'd be more realistic.

 

And no matter how great FFB sticks are, they wouldn't limit pulling too much either rainbowdashwink.png

 

That depends. You can make FFB sticks using Tesla motors if you're crazy enough.

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Pulling 21g's though.. I don't know, that's something else. I'm concerned. Surely, if being able to do that was as easy as it was displayed in the video, somebody would have done that in real life, right?

 

Read my post above this one. Control forces are too high for the pilot to pull that much. We don't model pilot strength in DCS in any noticeable way.

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Read my post above this one. Control forces are too high for the pilot to pull that much. We don't model pilot strength in DCS in any noticeable way.

 

What control forces? Unless you mean artificial ones, there are no direct control forces in the F14. As for the artificial control forces, remember that the F14 doesn't have fly by wire, there is no computer that determines the max ammount of g that you can pull dependant on the flight regime. AFAIK it doesn't even feature the limited CAS system present in the F15. Im 99% sure that Heatblur have modeled the ammount corrently, but there are at least a couple of real F14 pilots here that can confirm or deny this.

 

MAGZ has already stated that the plane allows you to break it, though its very forgiving if you know what you're doing but extremely bad piloting will get you killed in the F14.

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Would a real pilot really have the strength to pull full aft stick and accomplish 21 g's at that speed? If not then maybe heatblur should limit the amount of stick movement available to simulate a real pilots limitations.

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What control forces? Unless you mean artificial ones, there are no direct control forces in the F14. As for the artificial control forces, remember that the F14 doesn't have fly by wire, there is no computer that determines the max ammount of g that you can pull dependant on the flight regime. AFAIK it doesn't even feature the limited CAS system present in the F15. Im 99% sure that Heatblur have modeled the ammount corrently, but there are at least a couple of real F14 pilots here that can confirm or deny this.

 

MAGZ has already stated that the plane allows you to break it, though its very forgiving if you know what you're doing but extremely bad piloting will get you killed in the F14.

 

It seems there are three components to the artificial feel in pitch: simple spring tension (like we typicaly have in a desktop stick, although probably quite a bit stiffer) that resists stick deflection from centre, bob weights that add resistance to aft stick as you pull to prevent excessive sustained G, and the eddy current dampers that resist rapid movement to prevent excessive instantanious G.

 

While G isn't specifically monitored, Deano is saying there certainly are mechanisms there to prevent exceedances. Whether you can be strong enough to overcome them is up for debate I guess, but would be pilot dependent at any rate.

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While G isn't specifically monitored, Deano is saying there certainly are mechanisms there to prevent exceedances. Whether you can be strong enough to overcome them is up for debate I guess, but would be pilot dependent at any rate.

 

Yeah I get that. What Im trying to say though is that with the F14 it's probable that at certain flight regimes pulling the stick to its max deflection might be advantageous, while at others it might kill you. The pilot is trained to recognize this, with the help of the artificial forces, and limiting the deflection rate of the stick to prevent airplane damage or pilot death, would make it much less capable in many of it's other flight regimes.

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Yeah I get that. What Im trying to say though is that with the F14 it's probable that at certain flight regimes pulling the stick to its max deflection might be advantageous, while at others it might kill you. The pilot is trained to recognize this, with the help of the artificial forces, and limiting the deflection rate of the stick to prevent airplane damage or pilot death, would make it much less capable in many of it's other flight regimes.

 

I suggest you investigate how things like bob-weights in control systems work. They are designed react to G-force. So the more G the aircraft is pulling the higher the control forces become. This means that it doesn't stop you applying full back stick at slow speed/low G but then the controls weight up as the G-loading increases, sometimes to quite high levels. Therefore it doesn't effect control limits in other flight regimes.

 

My previous answers in this thread are in relation to CYLONs questions about whether any real pilot had pulled 21G in a real Tomcat, I was explaining how the control system in the real aircraft does its best to stop the pilot from over stressing the aircraft. I am not commenting on how control forces are represented in the sim.


Edited by Deano87

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I suggest you investigate how things like bob-weights in control systems work.....

 

The reason the vast majority of A-4 Skyhawk pilots in the RNZAF fathered girls - that depleted uranium bob-weight sitting between your legs! :huh:

 

Apparently prospective girl-swimmers are stronger and more resilient to radiation than boy-swimmers.

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I suggest you investigate how things like bob-weights in control systems work. They are designed react to G-force. So the more G the aircraft is pulling the higher the control forces become. This means that it doesn't stop you applying full back stick at slow speed/low G but then the controls weight up as the G-loading increases, sometimes to quite high levels. Therefore it doesn't effect control limits in other flight regimes.

 

 

Ahh okay. Got it. So the control column stiffens up the higher the G loading. Actually this opens up very interesting potential solutions to force feedback implementation for the module too, and that is something that I would very much like to see implemented in Heatblur's F14.

 

So now the question remains how much force was required to pull back on the stick for any given G in the real plane.

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