Newbie questions re: Learning to turn (and trying to avoid stalls)
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Cool stuff Mylonite. Blu3wolf is right, always keep your airspeed up appropriate to the maneuvre. It applies to many subjects for instance a simple climb. If you start to climb starting 250kts you will stall or bore to death. If you start with 400 kts, your airspeed will drop less and it should be relatively easy to maintain 350 kts all the way from sealevel to 20,000 ft. In any case, you will find it very hard to be at 250kts, climb and accelerate to 350 kts at the same time. The same thing applies to turns; first make sure your airspeed is right, then turn/climb/launch.
In BFM/dogfighting situations this is even more important and that’s where E-M charts come in handy:
http://www.f-16.net/forum/download/file.php?id=20016&sid=f5a2c2d0360d5acb5cec32b2092ebbd8&mode=viewThe line Ps=0 represents the amount of G’s (load factor) you can pull in full afterburner without losing energy (i.e. airspeed), in this case applicable at 15,000 ft and a combat weight of 21,000 lbs. See for instance 6 G’s and Mach .63. Lower G’s will increase your energy at that turn rate, higher G’s and you will lose energy (up to a stall in the extreme).
Apart from that, there’s no trick really, but you’ll pick it up quickly by instinct.You could also try and figure it out by yourself in the sim; pick an altitude, pick a certain airspeed and start turning to see at which G-load the airspeed remains constant. Two things to consider: the Ps=0 limit and the snap-turn rate. The former will tell you how to maintain or increase your energy, while the latter will bleed a lot of energy but give you the amount of angle available at that speed to point your nose towards the target. A diagram is less work, but less fun. Good luck!
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This is where just flying around in free mode can teach you something - it’s counter intuitive, but you can be too fast. Most - and I mean MOST, including myself - fly around way too fast when they first start out. I was having a difficult time doing head-on gun passes and asked a real fighter jock about what I was doing, described it, and he replied - “you’re arcing”…meaning I was coming to the merge way too fast. So I slowed down and then I started being able to gun a Mig-29 in the face. Consistently. AND - if I missed, I found myself far better able to stern convert post merge. Consistently.
Speed gets you rate, but slower speed gets you a tighter radius. What you need to figure out is the balance between the two. What I did (and still do) to learn and practice was to go out in free flight and do low level ground reference maneuvers - usually S-turns over/across a river or road - at various entry speeds; noting bleed rate/G/radius vs pull. By doing this you have a fixed reference to judge your rate and radius of turn…and can note that just reefing on G at some high airspeed doesn’t always get you the desired result you think you’re going to get.
Do a lot of this, and note what works and what doesn’t…after a bit you’ll develop a feel for when to pull and when to relax. I did.
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Many thanks for the advice!
As I’ve continued to play around in free flight, I’ve gotten a tiny bit more accustomed to turning without getting into a stall. If I’m trying to do anything in a hurry, like keep my nose pointed at a bandit post-merge, I’m still making the same ham-handed mistakes and stalling… though maybe a little less often. (I did manage to keep a Fulcrum in sight a little better today, and even to get an AIM-9 onto one of `em.) While flying solo, I’ve been able to get into a few more stable turn situations, making nice level turns at relatively constant G.
I’m starting to notice a few more of the basics. Never having flown a real aircraft, or even any other flight simulator, it’s fascinating to discover the things that real pilots probably take for granted!
Here’s an example: Getting a rough idea of AOA from the HUD. This is super basic, but it just occurred to me today. The gun cross shows me roughly where my nose is pointed. The flight path marker (FPM) shows me where my aircraft is actually going. In stable level flight, the jet will have a tiny bit of AOA, so the gun cross will be above the FPM. Makes sense. If the FPM drifts way down (in the frame of reference of the HUD, i.e. down towards the floor of the cockpit), then the aircraft’s AOA is getting high, and it’s bleeding off energy and heading towards a stall. So, a quick way to know that you’re making a decent turn is if you can turn without causing the FPM to drop too far below the gun cross. Roughly speaking, if the FPM is still on the HUD, I’m probably not doing TOO badly. It’s when the FPM gets an “X” over it, and gets pinned somewhere along the bottom of the HUD that I know I’d better find a way to get it back in view.
I’ve flown a few turns “on instruments”, and that’s been really fun. I just stared at the center console, with only a little bit of peripheral view outside. My goal was to establish a bank angle, give it some G, keep the altitude relatively constant, and most of all, find a way to do it without sending the AOA tape into the red zone. I still haven’t come up with a “method” for this, but it’s fun to try, and a couple of times I was able to get to 6 or 7 Gs without having sent the AOA indicator into the colored bands, or at least not much.
Looking at the relationship between the gun cross and the FPM, on the HUD, is basically a shortcut for doing this in a heads-up way.
I’m still no great shakes as a “turner”, but the most interesting thing I’ve looked at so far are the E-M charts, like TwanV pointed out, above. In another thread, I found a reference to the “HFFM” manual, and that’s where the E-M diagrams are. I think I’m beginning to understand them a little bit - they’re cool!
The E-M charts give me some specific scenarios to shoot for, as I try to develop a `feel’ for making good turns. Here’s how I’m interpreting them. I’ll use p. 123 of the HFFM as an example. This is “Turn Performance - 15,000 feet” for the F-16C Block 52.
Looking at this graph, I see two axes (Horiz: speed, Vert: Turn rate in deg/sec), and three sets of lines. The lines represent turn radius, G, and P-sub-S.
A word about P-sub-S… here’s what I think it means: I think it means something like “The sum of kinetic energy and gravitational potential energy”. One can be traded for the other, and the overall amount of energy can be decreased by drag or increased with the engine. I’m guessing the P-sub-S curves indicate the rate of rise or sink that the aircraft will experience if you’re making a level turn under the parameters indicated by the graph’s two axes and by the G lines and the radius lines.
Since I’m trying to build the basic skill of a level turn, I think the [P-sub-S = zero] line is telling me the set of conditions that should result in a level turn. Some combinations of throttle, airspeed, radius, and G will allow me to maintain a constant altitude. Others will result in a plane that’s ascending in a spiral. Others will result in a place that’s descending in a spiral. As an example, there’s a point on the [P-sub-S = 0] line where I’d be at 15,000 feet, in full afterburner, pulling 4G, at 0.65 Mach. That ought to result in a constant altitude. In contrast, if I went to 5G at the same Mach and full AB, my turn would tighten to 3000’ radius, and I’d be sinking at 400 ft/sec. I don’t think I could keep the FPM on the horizon line if I was maintaining these new parameters.
I don’t know if I’m reading the graph right, but that’s how it looks to me.
I’ve tried going out in free flight and doing this, but I haven’t been able to creep up to, and attain, any given set of parameters yet. There are still too many things to monitor: Bank angle, back stick pressure, altimeter, Mach meter/airspeed indicator. Having never done any real or simulated aircraft flying before, it’s a job of work, whoof! But it’s super fun, trying to keep all these plates in the air. :juggle: One of these days!
The comment about practicing near the ground was really interesting. With the tiny number of hours I have in the sim so far, I’ve been amazed at how relatively easy it seems, to fly near the ground. Terrain flying is so much fun! I suppose everyone goes nuts flying NOE when they first start the sim, but gosh I enjoy it. I’m amazed how rarely I crash, given what a noob I am. I assume it’s just the presence of such a big, nearby visual reference that makes it possible. Something about having the ground nearby makes everything feel much more intuitive.
Fun journey up the learning curve - thanks for the advice and for listening to my out-loud thinking! Someday I’ll be out there in the campaign, making decent turns! (And ramp-starting, and taking off, etc… can’t forget to develop the other skills, too!) Need to learn about Discord, too.
Mylonite470
(I have a weird screen name because I used my PlayStation username when I set up my BMS account. I should have given it more thought!)
(Mylonite is a type of rock. Viper drivers at Luke AFB could find plenty of it in some of the mountains around Phoenix.) -
In combat start your initial manœuvre never below Mach 0.8 to keep your energy
If you fly for instance Mach 0.8 with low weight , and low alt you will be above PS = 0 curve and will be able to sustain 7-8g no problem indefinitely
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Sounds like you’ve figured it out - the gun cross is your nose, the FPM is where you are going. The difference between the two is your AOA - so don’t bother trying to read numbers so much as learning to “quantify” AOA at a glance at the relative positions of those two markers, bearing in mind that you’ll hit a limit at 25 and then no matter how hard you pull that’s all you’ll get and the jet will start to lag your inputs…and at worst you’ll stall.
Next comes speed - now you can adjust your pull; relax if you’re bleeding/pull harder if you’re not/add throttle if required. You’ll find you only have so much G available at a given altitude no matter how fast you’re going; and then you’ll want to pay attention to radius of turn and how small you can make that…which again, may mean you need to slow down and/or let the jet fall if you are high enough and have the room - trade altitude for airspeed. That’s part of the energy balancing act. But what you want to do is stay in the “corner bucket” to maintain best turning performance…remember that you can be too slow or too fast.
Another ROT to remember - lead to close/lag to pursue and know when you need to do which….and worry more about where your aircraft is going - not your nose - until you are in a state where your weapons will bear. Which depends on which weapon you are using.
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Thanks very much, Stevie, those sound like good, simple rules of thumb. Nice and straightforward.
Turns are making more sense now, and I find that I can avoid high AOA (and stalls) better after some more practice.
I’m getting up to 0.8 Mach before turning, like Mav-jp suggested, and that seems to make me less prone to stalling once I initiate the turn. I just try to keep the FPM visible in the HUD, and that seems to work well, too. I might not be making the best turn at any given moment, but I am at least able to keep turning, and that feels really good after all those stalls. Sometimes it’s a descending turn, sometimes ascending, sometimes I’m at MIL power, sometimes I’m in AB, but at the very least, I’m going around in a circle as though I were engaged with a bandit. As I make these “FPM on HUD” turns, I am playing with making small variations to bank angle, back stick pressure, and throttle, and I think I’m building a little bit of feel for it. There’s a long way to go, but it seems like I’m starting to wire a tiny bit of “feel” into my nervous system, and that feels really good.
I think a big part of what I’m enjoying about Falcon BMS is that it affords a chance to acquire new skills. I find the whole topic of skill acquisition to be really interesting.
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As I’ve continued to play around in free flight, I’ve gotten a tiny bit more accustomed to turning without getting into a stall.
Alright, so lets start with some terminology notes. A stall is where the aircraft loses lift due to the airflow over the wings getting interrupted, no longer being smooth. Before a stall, an increase in angle of attack results in an increase in lift. During a stall, this is no longer the case.
In an F-16, the flight computer keeps you away from the stall. You can pull back on the stick all day and not stall it. You may not get the nose any higher, but this is not due to a stall, rather the flight computer ignoring your stick back input.
I’m starting to notice a few more of the basics. Never having flown a real aircraft, or even any other flight simulator, it’s fascinating to discover the things that real pilots probably take for granted!
mmm, nope. Real pilots study it extensively, to learn it in detail.
Here’s an example: Getting a rough idea of AOA from the HUD. This is super basic, but it just occurred to me today. The gun cross shows me roughly where my nose is pointed. The flight path marker (FPM) shows me where my aircraft is actually going. In stable level flight, the jet will have a tiny bit of AOA, so the gun cross will be above the FPM. Makes sense. If the FPM drifts way down (in the frame of reference of the HUD, i.e. down towards the floor of the cockpit), then the aircraft’s AOA is getting high, and it’s bleeding off energy and heading towards a stall. So, a quick way to know that you’re making a decent turn is if you can turn without causing the FPM to drop too far below the gun cross. Roughly speaking, if the FPM is still on the HUD, I’m probably not doing TOO badly. It’s when the FPM gets an “X” over it, and gets pinned somewhere along the bottom of the HUD that I know I’d better find a way to get it back in view.
I’ve flown a few turns “on instruments”, and that’s been really fun. I just stared at the center console, with only a little bit of peripheral view outside. My goal was to establish a bank angle, give it some G, keep the altitude relatively constant, and most of all, find a way to do it without sending the AOA tape into the red zone. I still haven’t come up with a “method” for this, but it’s fun to try, and a couple of times I was able to get to 6 or 7 Gs without having sent the AOA indicator into the colored bands, or at least not much.
Alright, there is a foolproof method to achieve this, but its not useful for you. Try it though: Accelerate to 650 knots or more, then pull the stick all the way back for 9G. The AOA indicator should stay out of the colored section.
There is a relationship between lift and angle of attack. For low angles of attack (say less than 40° for many wings), an increase in angle of attack causes an increase in lift. To get to 9G, you need to generate 9 times as much lift as there is weight.
There is also a relationship between lift and airspeed. For all airspeeds, an increase in airspeed causes a large increase in lift. For a given gross weight, you need a fixed amount of lift to get to 9G. So, we could go to a high angle of attack at a low airspeed, or we could go to a small angle of attack at a high airspeed.
So, if you want to get a high G turn, have a high airspeed.
The problem with this is that above 450 knots, your turn rate decreases, and your turn radius increases drastically.
Looking at the relationship between the gun cross and the FPM, on the HUD, is basically a shortcut for doing this in a heads-up way.
I’m still no great shakes as a “turner”, but the most interesting thing I’ve looked at so far are the E-M charts, like TwanV pointed out, above. In another thread, I found a reference to the “HFFM” manual, and that’s where the E-M diagrams are. I think I’m beginning to understand them a little bit - they’re cool!
They are VERY cool! They are also key to understanding the performance of the F-16 in a high G turn.
The E-M charts give me some specific scenarios to shoot for, as I try to develop a `feel’ for making good turns. Here’s how I’m interpreting them. I’ll use p. 123 of the HFFM as an example. This is “Turn Performance - 15,000 feet” for the F-16C Block 52.
Looking at this graph, I see two axes (Horiz: speed, Vert: Turn rate in deg/sec), and three sets of lines. The lines represent turn radius, G, and P-sub-S.
A word about P-sub-S… here’s what I think it means: I think it means something like “The sum of kinetic energy and gravitational potential energy”. One can be traded for the other, and the overall amount of energy can be decreased by drag or increased with the engine. I’m guessing the P-sub-S curves indicate the rate of rise or sink that the aircraft will experience if you’re making a level turn under the parameters indicated by the graph’s two axes and by the G lines and the radius lines.
Alright, so P sub S is Specific Excess Power. This has a strong relationship with Total Mechanical Energy, which is the sum of kinetic energy and gravitational potential energy. Lets say the aircraft is at a point on that graph where it has Ps of 0. This means that for that combination of airspeed, altitude and G, that with the power setting on the graph (either MIL or MAX AB), the aircraft will not gain or lose total mechanical energy (which Im just going to call energy from now on). If the Ps value is positive, this means the aircraft will gain energy for that G, and it will result in either an increase in airspeed or an increase in altitude (or some combination thereof). If the Ps value is negative, the aircraft will lose energy for that G. The Ps = 0 line then shows you the steady-state sustained performance of the F-16 for that altitude and all airspeeds on the graph.
You will also note that there are different graphs for different power settings (MIL/MAX AB), different drag values (drag index = 0/50/100/150/200/250), and different altitudes. Then the graph values get modified by air temperature and density, and then the graph has values for varying airspeed and G to get turn rate, turn radius and specific excess power. It is typical, but not universal, to indicate Ps in feet per second.
Since I’m trying to build the basic skill of a level turn, I think the [P-sub-S = zero] line is telling me the set of conditions that should result in a level turn. Some combinations of throttle, airspeed, radius, and G will allow me to maintain a constant altitude. Others will result in a plane that’s ascending in a spiral. Others will result in a place that’s descending in a spiral. As an example, there’s a point on the [P-sub-S = 0] line where I’d be at 15,000 feet, in full afterburner, pulling 4G, at 0.65 Mach. That ought to result in a constant altitude. In contrast, if I went to 5G at the same Mach and full AB, my turn would tighten to 3000’ radius, and I’d be sinking at 400 ft/sec. I don’t think I could keep the FPM on the horizon line if I was maintaining these new parameters.
I don’t know if I’m reading the graph right, but that’s how it looks to me.
Constant energy state, not necessarily constant altitude or airspeed. But if you are at the performance on the Ps = 0 line, then holding altitude constant will mean holding airspeed constant if you hold the appropriate G. If the temperature and density match standard day conditions (which the graph assumes), and you are at the altitude for the graph.
For the example you cited, if you hold your bank angle at 75° for that 4G turn and 0.65 IMN, you will be level. Actually with that bank angle and G, you will be level, regardless of airspeed. But at 0.65 IMN, you will hold airspeed, as according to the graph you have zero specific excess power, and so no ability to accelerate without trading altitude.
If you then instantly increase G to 5G, without altering bank angle, you will start to climb, and you will start to slow down, such that your total mechanical energy will decrease at 400 ft/sec (you could convert that into joules if you like I guess). Your altitude will actually increase though, and your airspeed will decrease. If you hold that G and bank angle long enough, your angle of attack will keep increasing as your airspeed decreases, and if you keep holding that G you will run into a FLCS limiter, where the F-16 flight computer will start to push the stick forward, decreasing your available G for you, until the aircraft reaches 26° angle of attack, at which point the aircraft will start to nose over, even if you hold the stick all the way back.
I’ve tried going out in free flight and doing this, but I haven’t been able to creep up to, and attain, any given set of parameters yet. There are still too many things to monitor: Bank angle, back stick pressure, altimeter, Mach meter/airspeed indicator. Having never done any real or simulated aircraft flying before, it’s a job of work, whoof! But it’s super fun, trying to keep all these plates in the air. :juggle: One of these days!
The comment about practicing near the ground was really interesting. With the tiny number of hours I have in the sim so far, I’ve been amazed at how relatively easy it seems, to fly near the ground. Terrain flying is so much fun! I suppose everyone goes nuts flying NOE when they first start the sim, but gosh I enjoy it. I’m amazed how rarely I crash, given what a noob I am. I assume it’s just the presence of such a big, nearby visual reference that makes it possible. Something about having the ground nearby makes everything feel much more intuitive.
Helps that you are flying an incredibly high performance, incredibly easy to operate aircraft. The F-16 has the advantage of a flight computer which does the complicated stuff for you, so you can focus on combat flying.
Practicing near the ground can be a useful reference, but it obviously adds in its own risk factors. Real F-16 pilots do practice this flying after they complete the air to air section of their syllabus, in their Low Altitude Step Down Training section.
Id like to again take the opportunity to recommend trying out the Aircraft Handling Characteristics exercises included in your install folder, and also available online: http://falcon.blu3wolf.com/Docs/Basic-Employment-Manual-F-16C-RoKAF.pdf
Page 3-40 (found on PDF page 88 ) is the first of the AHC exercises, and is the first set of exercises flown by real F-16 pilots.
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Ps is your specific Power (net). It is a measure of how much energy per second you would be adding to the jet given some conditions. If you are maneuvering at Ps 0 then your total energy (kinetic, potential) is constant. If negative you’re shedding energy. If positive you’re adding. Kinetic and potential are interchangeable. You can imagine dropping altitude but speeding up or the reverse or any combination where the addition comes out to plus, minus, or zero. The units are in feet per minute of climb which can apply kinetic or potential. It’s weird to think of adding kinetic energy in units of “feet per minute climb” but energy is energy.
~440-450 knots is your best turn rate potential but you can’t maintain maximum potential for very long if you actually try to use it. “Corner” is a good place to be to be as ready as possible to do something. Sustained turning is best ~330 knots. If you fly 440 corner sustained you’ll be super ready to do an awesome turn but your actual turn rate in this condition will be poor. Once you drop below the 280-350 knot sustained band everything starts to suck and it’s really hard to recover. If your fight gets this slow you probably shouldn’t be thinking about good turn rates but scissors and other slow trickery.
A good practice and what real pilots do is a constant speed turn. Example you’re at 28,000’ at ~4/5th throttle tootling along at 300 KCAS. You pass steerpoint 2 heading to steerpoint 3 for maybe ninety degrees of heading change. One way to do this is to set throttle to MIL and bank for the turn and pull just hard enough to maintain speed, neither 299 nor 301. Then on roll out throttle back for cruise. This kind of “pulling the stick acts like the throttle” thinking translates well to dogfighting.
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Thanks very much, Stevie, those sound like good, simple rules of thumb. Nice and straightforward.
Turns are making more sense now, and I find that I can avoid high AOA (and stalls) better after some more practice.
I’m getting up to 0.8 Mach before turning, like Mav-jp suggested, and that seems to make me less prone to stalling once I initiate the turn. I just try to keep the FPM visible in the HUD, and that seems to work well, too. I might not be making the best turn at any given moment, but I am at least able to keep turning, and that feels really good after all those stalls. Sometimes it’s a descending turn, sometimes ascending, sometimes I’m at MIL power, sometimes I’m in AB, but at the very least, I’m going around in a circle as though I were engaged with a bandit. As I make these “FPM on HUD” turns, I am playing with making small variations to bank angle, back stick pressure, and throttle, and I think I’m building a little bit of feel for it. There’s a long way to go, but it seems like I’m starting to wire a tiny bit of “feel” into my nervous system, and that feels really good.
I think a big part of what I’m enjoying about Falcon BMS is that it affords a chance to acquire new skills. I find the whole topic of skill acquisition to be really interesting.
Good work! You’re onto it - getting steady on the stick is part of it too. I’d suggest watching airspeed over Mach for maneuver entry though - that’s how most entry conditions are specified. So…vary your altitude, enter a turn at 0.8 Mach, and see/watch how things change wrt airspeed and bleed rate. Good stuff…
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I really enjoyed this book, and helped immensely with my flying generally. What it made me realise more than anything else is the importance of AoA. The author gives a great example of where the Wright Brother’s Flyer had a flag at the end of pole so that they could see the angle of attack. Those boys new a thing or two about flying that was promptly forgotten.
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Thanks very much for the book recommendation, rmax! I just ordered a copy. That looks like a great book for a new, non-pilot person like me to learn a lot of fundamentals from. The “See How It Flies” book on Blu3wolf’s website looks very informative, too.
Years worth of studying and learning to do, that’s for sure!
It would be interesting to know what percentage of F-16 pilots have had prior civil-aviation experience (or even computer flight sim experience) before joining the military. I assume it’s a large percentage, but I don’t really know.
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It would be interesting to know what percentage of F-16 pilots have had prior civil-aviation experience (or even computer flight sim experience) before joining the military. I assume it’s a large percentage, but I don’t really know.
I cant speak on behalf of F-16 pilots, but I can note that the Royal Australian Air Force recommends only a little flight time to prospective pilot applicants. Totally inexperienced pilots will find the first few hours very overwhelming, but experienced pilots will find it hard to relearn how to do everything the air force way. Its hard to break habit patterns. They dont disallow experienced pilots, but they do find that most commercial pilots find it more difficult to unlearn everything.
On the topic of prior experience though, its worth noting that they dont get straight into an F-16 on joining the military. USAF pilots flight training starts out in Undergraduate Pilot Training (UPT), in a T-6. You graduate from that as a qualified pilot, and if you scored well enough to get onto the Fighter track, you go into Intro to Fighter Fundamentals (IFF) in a T-38. Then you learn fighter combat, air and ground. Once you graduate from that, again if there are slots available and if you scored at the top of your class, then you can get into F-16s, in Initial Qualification Training (IQT), and that is followed by Mission Qualification Training (MQT), once you get posted to your squadron.
So by the time an air force pilot gets to training the exercises described above, in an F-16, they already know a great deal of theory about flying, and have a great deal of experience in other aircraft. And they have spent weeks and weeks studying the F-16, how it works, and how it flies, so that none of it should come as a surprise when they do finally get in the air.
For the new simulator pilot, its a lot to take in at once.
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My copy of “Stick and Rudder” arrived, and I’m finding it to be a really interesting book! I’m a little less than halfway through, so far.
I really enjoy reading Langewiesche’s explanations of how airplanes work, in a practical, from-the-pilot’s-POV way. It’s really interesting the way he emphasizes the Angle of Attack. Having discovered - in a crude way - that I was inducing a high AOA during my first attempts to turn the simulated F-16, this really caught my attention.
I also like his writing style. I get the impression that when he first wrote the book, back in the 1940s, he was somewhat frustrated with the then-current ways in which pilots were taught. I gather that he wished a lot more emphasis were placed on the AOA and its fundamental importance. I also like how he’s quite honest when he’s about to give the reader an oversimplified or not-quite-accurate explanation, but takes great pains to justify why he thinks it’s a useful `white lie’. I also love how he tells it straight when he warns the reader that it’s going to take a little while to explain something properly.
Earlier in this thread I speculated that P-sub-S might mean “the sum of kinetic energy and gravitational potential energy”, and I was wrong about that. What I was describing was something closer to “total mechanical energy”, I think. And so I learned a little more about what P-sub-S really is, and how having a positive, nonzero P-sub-S could allow you to do things (like gain altitude during a turn that has certain parameters) that you couldn’t do if your P-sub-S was negative. Langewiesche’s Chapter 3 - “Lift and Buoyancy” - reminds me a lot of P-sub-S, at least in my limited, most-definitely-incomplete way of understanding it so far. I don’t want to go out a limb and claim that “aha, the subject of Chapter 3 is specific excess power!” I’m not sure enough, yet, to make that claim with any vehemence. Need to study this stuff some more. But it sure sounds like it. Fascinating stuff!
And I love the terms he uses for “this mysterious quality” ! He describes how pilots often call it “lift”, even though they don’t mean it the way an engineer does. Then he goes on to propose the names “The Zoom Reserve”, “Potential Excess Lift”, “Remoteness From The Stall”, “Lowness of Angle of Attack”, and my personal favorite - “Firmness of Sustentation” I love it!
Someday I want to be able to say to myself “I got that MiG kill in Falcon BMS because of my aircraft’s superior Firmness of Sustentation at that point in the dogfight”. That would be a total hoot! Would be a great title for a Youtube video of a dogfight, lol.
Tons and tons more to learn, but this book makes learning some of the basic basics of flight a lot of fun.
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Study of the coefficients of lift and drag and their ratio is enlightening. US Navy aviation education is historically superior and emphasizes alpha in a way that land-based did not. They had to understand slow speed flight to operate from ships. Understanding of aerodynamics has a kind of staged progression from lay to civil aviation to naval aviation to aero engineering. The trade off between the pure science of knowing and utility of convention to operate at a certain level is appreciated. A lot of people get caught up in doctrine of a particular school of thought. Ask a lay, pilot, and aerodynamicist what’s a stall and get three different answers all operationally correct to the world they want to apply it to.
P-sub-S, as a physicist, I like to break down into parts. It’s all right there in the name. “P” is power. Power is time-rate-of-energy-change. It’s not E, energy, itself but the rate of adding and subtracting from that bank account. The “sub S” is better appreciated by taking the scenic route. “sub S” means “specific” and it’s called “sub” for “subscript” because they write the S as a little letter below as a label to describe a distinct kind of power, specific power. Specific is used in engineering commonly but in an uncommon way. It refers to the intrinsic property as opposed to an extrinsic one.
An example goes like this: What is more valuable, sand or gold? Gold, naturally. But I have a gigaton of sand and you have a nanogram of gold. My huge pile of sand is worth more, has a greater extrinsic value, than your tiny speck of gold. But you aren’t interested in my particular mountain of sand and your particular speck of gold. You want to learn about sand as compared to gold in general. We invent a new measure called specific value which is the value per a specified amount (e.g. kilogram). Looking at the specific value of sand and gold we compare their intrinsic properties or properties which depend only on the kind of sample object, not the size of it.
An F-16 and B-52 are in a dogfight. The B-52 has a huge potential energy and kinetic energy advantage over the F-16. Think back to physics class E is a function of mass and the B-52 has no shortage of that. It also has a power advantage with 7 more jet engines. Despite this energy advantage the F-16 flies behind the B-52 and wins the fight. Why? For all the B-52s E and P advantages it had a lot of M to haul around. Maneuvering is a function of the E and P divided by mass which are Es and Ps. That’s the specific energy and power or how much energy and power each pound of bomber can call its own. Comparing Es and Ps between the B-52 and F-16 shows why the F-16 won. The F-16 has more E and P per pound of gluteus maximus; it had superior Es and Ps.
As far as “gut feel” words, they have their place. In operation the academic parameters may not be readily accessible mentally. Natural feeling paramters “firmness” “spriteliness” etc. are absolutely valid references.
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need more speed for higher G turning. 400knots, 4G steady is a good practice cause that speed (0.9 mach) and Gs is what you often do in tactical movement.
if you can’t keep it steady within a full 360 turn… then just keep pulling the stick for 720, 1080 or even more till your can make it solid. -
Thanks for posting that video, Ironhead. That really gives me something to shoot for. I really like the way you’re executing those turns. No fuss, no muss, just straight into a 4G turn. The altitude tape stays steady, the airspeed tape stays steady, and the G-meter stays steady, right at 4G. Then a reversal and right into the same turn, going the other way.
Oh, what throttle setting do you use in that turn? Are you in afterburner?
Turn goals for yours truly! I would love to be able to turn my virtual F-16 that way.
So far, I’m pretty far from being able to do it, but I’m practicing. Trying different things, seeing what works, what doesn’t. Hoping to develop the `touch’, someday, to be able to go right into a turn like that.
At present, I’m not getting very close. Bleeding off airspeed, FPM going up or down, getting into “mushing AOA/airspeed”, and the like. But someday, someday, the
touch' will (hopefully) come! Trying to wash off the (imaginary) temporary tattoos on my hands that say "Armour Star". Maybe I should learn the basics of how to change my Cougar's SSC sensitivity, too. I'm still pretty intimidated by keyfiles, the CCP, Foxy, TARGET, and the like, but maybe it's worth taking on those dragons, too, see if that helps. So far I've gotten my HOTAS buttons
realistically’ mapped, purely through the BMS interface. It might be time to take a deeper dive into how controllers interface with the sim. Then again, it’s a poor craftsman who blames his tools… time to cue up another practice session. -
Thanks for posting that video, Ironhead. That really gives me something to shoot for. I really like the way you’re executing those turns. No fuss, no muss, just straight into a 4G turn. The altitude tape stays steady, the airspeed tape stays steady, and the G-meter stays steady, right at 4G. Then a reversal and right into the same turn, going the other way.
Oh, what throttle setting do you use in that turn? Are you in afterburner?
Turn goals for yours truly! I would love to be able to turn my virtual F-16 that way.
So far, I’m pretty far from being able to do it, but I’m practicing. Trying different things, seeing what works, what doesn’t. Hoping to develop the `touch’, someday, to be able to go right into a turn like that.
At present, I’m not getting very close. Bleeding off airspeed, FPM going up or down, getting into “mushing AOA/airspeed”, and the like. But someday, someday, the
touch' will (hopefully) come! Trying to wash off the (imaginary) temporary tattoos on my hands that say "Armour Star". Maybe I should learn the basics of how to change my Cougar's SSC sensitivity, too. I'm still pretty intimidated by keyfiles, the CCP, Foxy, TARGET, and the like, but maybe it's worth taking on those dragons, too, see if that helps. So far I've gotten my HOTAS buttons
realistically’ mapped, purely through the BMS interface. It might be time to take a deeper dive into how controllers interface with the sim. Then again, it’s a poor craftsman who blames his tools… time to cue up another practice session.4Gs and afterburner would mean accelerating unless in quite a climb.
Perhaps your stick is overly sensitive, or perhaps you are a bit ham-fisted. You want a linear response from your stick - no alteration of sensitivity as you move the stick in other words. And you want to be able to make small, precise inputs - a stick which has slop in it is going to make that difficult to impossible. Ideally, you take your hands off the stick, the aircraft keeps doing what its doing. You grab the stick and apply a little back pressure, the nose starts to rise slowly. You apply some roll input, establishing and maintaining a steady roll rate, keeping the stick pressure back, putting the aircraft into a barrel roll. You control the roll rate so as to avoid losing excessive altitude.
If that sounds difficult, it would be worth figuring out if the issue is with the tools or the craftsman. Either way, its something you can fix. If its a control issue, fix it! That might mean repairing or replacing the controller, or it might mean adjusting some settings. If its a pilot input error, you need to take some time to get to know your controls - no one starts out flying like Chuck Yaeger.
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I have been trying to duplicate the turn that Ironhead demonstrated in his Youtube video. Here’s a 10-minute video of me trying to duplicate the same turn:
The first 2 or 3 minutes give the general idea.
My goal is to do like Ironhead did:
Maintain 20,000 feet altitude
Maintain 4G
Maintain 400 ktsIronhead did a remarkable of getting right into the turn, and holding those parameters very steadily. As my video shows, I can’t quite get into a given set of turn parameters like that, and when I do turn, I do a lot of what I’ll call “exploring parameter space”, trying to get into the set of parameters that I’m shooting for. There’s nothing magic about 4G / 20,000 feet / 400 kts, I’m just trying to duplicate the example I was given.
During the first 30 seconds or so of my video (the one linked above), I hold things fairly steady (after a couple of hiccups while getting into the turrn), but I’m not at 4G, and after about 30 seconds, my parameters start to wander. Airspeed drops, and AOA goes up. Then I start hunting around, trying to get towards my `assigned’ parameters.
The thing that fascinates me so much about Ironhead’s demo is that they’re able to get right into the turn they want, no fuss, no muss. It looks as simple as “deflect the stick to the side until you’re at the right bank angle, then pull back to apply Gs”. And maybe that is how they do it. But it’s fascinating to see how well they’ve got that wired into muscle memory - it’s a neat demonstration of what an experienced sim pilot’s skills are like. Somehow, during those few seconds when they’re transitioning from [straight & level] to the turn, they apply exactly the right control movements to take the plane on a “path” through the [bank/airspeed/G parameter space], such that they wind up in a stable equilibrium for a full 360 degrees of turn. And they do it quickly, with no messing around, no experimenting or hunting. Neat!
In my video, we can see what it’s like when an inexperienced pilot tries to navigate the parameter space, and takes the wrong path through it. I wind up in a realm of what I’d call “unstable equilibria” - i.e. flight parameters that end up with varying airspeed, G, AOA or some combination of those things. What a fascinating challenge this is.
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Pulling too much G so your airspeed drops. Solution: less aft stick pressure.
Airspeed rapidly increasing: Not enough G, or nose too low, or too much power (or some combination of the above). Fix any or all of those.
Nose high, losing airspeed: lower the nose, less aft stick pressure.
You were losing speed when holding 4G level at 20K, so you werent going to be able to hold 400 knots. Were you flying the same aircraft, with the same weight and drag?
The thrust matters, the weight matters, and the drag matters. Most all F-16s have very similar drag if they are clean. External stores tend to make more difference than the airframe, with some exceptions. How much fuel you had remaining makes a difference - you get better performance with a mostly empty fuel tank(s). Fuel level and whatever stores you might have been carrying would be likely culprits, along with if you were flying an older F-16 which has less thrust.
As far as controlling the aircraft… it is as simple as setting power, then setting bank angle, then setting G. But it sure helps a lot to be able to do all that without consciously thinking about it, just doing it.
Also, your video makes it look like you have the basic controls sorted out. Id start looking into the aircraft handling exercises and demonstrations from this point. Page 3-40, remember. AHC and HARTS.
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Sorry I haven’t replied in a while, I spent last week hiking and 4-wheeling in the California desert. Took a couple of rest days at the place called “Star Wars Canyon / Jedi Transition” to watch planes. It’s mostly F-18s, but we had a few nice Viper passes, too. Always cool to see and hear jets flying down the canyon. Unfortunately, one of the days I was there was the day after the Thunderbirds crash, so there was the sad thought of the pilot who lost his life, and Nellis was shut down. But jets still flew, and it’s still a beautiful part of the desert.
Thanks for bringing up the issue of weight and drag, Blu3wolf. Ironhead, if you happen to see this message, do you remember the configuration of your jet during the 20Kft / 4G / 400kts turns that you demonstrated? I’d be curious to see if they’re the same as what I’m using, when I go into a dogfight with no opponent plane.
As I’ve continued to practice turns, I’m trying out combinations of side-deflection of the SSC at the same time as starting to pull Gs. That is, pulling both to the side and backwards at the same time. The tip of the SSC would trace out something like half of a parabola as it comes backward. This seems to help a bit, as opposed to purely giving side deflection, then allowing the stick to return to neutral, then pulling back for Gs. My nose doesn’t drop as much, and I may be “mushing” a little less.
Still need to do the AHC and HARTS drills. Those will probably build some good basic `feel’ for how the aircraft handles. Clearly, people like the USAF have a good reason for doing them.