Aces High Bulletin Board
General Forums => Aces High General Discussion => Topic started by: Nuku on January 31, 2001, 10:30:00 PM
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In two situations already, while extending away from a furball, I end up with a similar aircraft on my 6 (i.e. La5 vs La5, P-51 vs P-51). With my aircraft cleaned up, with WEP going, I figure there is no way he'll be able to close the range to fire after the range has stabilized, with him level on my 6, static at 1.8 to 1.5.
Then, on these two occaisions, the pursuer does something I didn't think would work: they go into a shallow dive, trading altitude for airspeed. This allows them to close the distance by about 200-300 yards (1.5 to 1.2 say) but they're below me. Then they start a shallow climb back to my altitude. This should slow them down, as they just trade the KE energy back for PE (alt). By conservation of energy, I would expect them to end up back where they started, but I find that they GAINED distance on me (100 to 200 yards).
After about 3 or 4 of these, they've closed to under 1000 yards and can start firing.
I'm scratching my head here: WHERE did they get the extra energy?? The ups and downs of their sinusoidal flight path is definitely more distance than my straight-and-level flight. My flaps were up, WEP was going, I was trimmed out, and I had no fuel tanks or ord strapped on.
I've read that "unloading" the aircraft to zero-G is a good way to accelerate OUT of a fight, but I've never read that it's a good way to catch someone. Can someone enlighten me on how this works?
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The present flight model retains of lot of energy. Some say too much. An AC should slow down when climbing as you stated but in AH they don't seem to slow as much as in other sims/flight models after the AC gains E. I won't argue whether this is right or wrong- just seems to be the way it is.
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This is some thing that has always bothered me also. There is no way this could happen in reality. As long as your sure your plane and his is traveling at the same speed.
Think of it as 2 cars side by side on 2 different roads. One road stays straight and level, the other road goes downhill then back up to the same level. In real life any energy the downhill car picked up would be lost on the uphill climb. Also, the distance becomes greater while the car goes downhill, so that also needs to be covered.
There are a few planes that retain E like forver. If I named them, we'd have another flame war. So, all I can say, the E model does need some neutering.
fscott
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A few things should be mentioned. The la5's engine has a MUCH higher output if the plane is below 8k alt. The p51 also has altitudes where it performs better. The p51 is very sluggish below 15k. Above 15k the next gear in the supercharger kicks in and performance increases.
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bloom25
THUNDERBIRDS
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In the long run the pursuer will lose ground with this technique. But yes you can gain ground in the short term.
PS Conservation of energy doesn't apply - thrust and drag see to that.
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Oh GAWD! Dont change the FM! I've just re-learned to fly and fight with this E-saving thing (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
Jokes apart, try to do a landing pattern with no engine (say at 200mph TAS) and you'll understand how much E this FM retains.
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Originally posted by bloom25:
A few things should be mentioned. The la5's engine has a MUCH higher output if the plane is below 8k alt. The p51 also has altitudes where it performs better. The p51 is very sluggish below 15k. Above 15k the next gear in the supercharger kicks in and performance increases.
Good point, but just to clarify, the initial post pertained to like model planes. Not different types of planes like 51 vs La5.
-Ding
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Originally posted by bloom25:
A few things should be mentioned. The la5's engine has a MUCH higher output if the plane is below 8k alt. The p51 also has altitudes where it performs better.
listen to this guy - i was cursin up a storm last night when he caught my p51 in an la-5!!
but....how did he....i was...oh never mind..*&%#
be mindful of what tactic you are using at what altitude, the speed might not be there for you as mentioned in this thread...
(http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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If the same plane, starting from the same E-state, can gain ground by a shallow dive followed by a shallow climb, then there is an error in the FM.
This sort of tactic should cause the plane to end up farther behind than he was to start with, and slower too.
J_A_B
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Originally posted by Nuku:
I've read that "unloading" the aircraft to zero-G is a good way to accelerate OUT of a fight, but I've never read that it's a good way to catch someone. Can someone enlighten me on how this works?
Hi Nuku
They were not simply unloading, and this is a valid and aerodynamically correct procedure. I believe the technique is part of current USAF tactical doctrine. It is so effective against a similar aircraft that I've even been called a cheat for being able to catch guys who started out of gun range with a slight E advantage.
I've just submitted an article that explains how and why it works to SimHQ and I'll post the link as soon as it goes live.
Badboy
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Originally posted by fscott:
This is some thing that has always bothered me also. There is no way this could happen in reality.
fscott
Hi fscott
It does happen in reality, and modern fighter pilots use that technique to good effect. I've been doing it for years. It has probably been so effective all this time because so few people know of it.
I hope my latest article will fix that.
Badboy
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Originally posted by funked:
In the long run the pursuer will lose ground with this technique. But yes you can gain ground in the short term.
PS Conservation of energy doesn't apply - thrust and drag see to that.
Hi funked
The pilot in the example was not applying the technique correctly, or he wouldn't have been doing a saw tooth dive and climb. My guess is that he was doing that because he wasn't actually aware of the V numbers for proper application, but even so, he made it work. The fact is that this does work in the long term, the longer it is applied the bigger the energy advantage becomes.
Also, conservation of energy always applies, you just can't ignore the thrust and drag. Factor them in, and everything will balance out nicely.
Badboy
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Originally posted by J_A_B:
If the same plane, starting from the same E-state, can gain ground by a shallow dive followed by a shallow climb, then there is an error in the FM.
This sort of tactic should cause the plane to end up farther behind than he was to start with, and slower too.
J_A_B
Hi J_A_B
I believe the flight model is behaving correctly in this respect. Sorry to hold back on the details, but once you read how this works you won't just accept it, you will probably be using it yourself (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
It is a situation that doesn't come up very often because when different aircraft types are involved, normal performance disparity can negate the effect. I only use it in a similar aircraft engagement and I've had good results with it.
A typical example might be after I've been unsuccessfully bounced by a pilot who then climbs away instead of using his energy advantage to press for the kill.
It is possible to eventually catch them, but only if they allow you to, and they probably will if they don't know how it works. When your adversary understands what you are doing it is very easy to prevent.
Badboy
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Since I'm no Ph.D and said what I did based only on my experience playing other simulators (quite a lot of them), I will assume that the people who posted that this IS possible are right.
To which I ask two things:
1. How easy is this to accomplish in the real world, compared to how easy it is in the game? Why wasn't this sort of tactic ever mentioned by WW2-era pilots? Is this something which in the real world only applies to Jet aircraft with afterburners?
2. Why does no other WW2 simulator allow this sort of tactic? (aside from a console game I used to have) Is this the sort of tactic that, while possible, wasn't practical with real WW2-era airplanes?
Thanks,
J_A_B
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Hi J_A_B
> Why wasn't this sort of tactic ever
> mentioned by WW2-era pilots?
I think similar aircraft engagements have been fairly rare, Spitfires have engaged other Spitfires, but that was after WWII. Even so, a protracted tail chase scenario was not very common, mainly because real pilots are much more fuel conscious than we are and an extending pilot would probably push the throttle past the wire, and push the manifold pressure to detonation. Few pilots would want to follow that, it's the sort of thing you only do if your life depends on it. Not to mention that a protracted chase is unwise if you care about survival, because it not only pinpoints your position to the bandits buddies, but it makes you very predictable. Also most real pilots who were serious about getting out of dodge, dived out of a fight, all the way to the deck if needed. In that situation it doesn't work anyway.
Also, the method used to predict that type of performance advantage wasn't developed for another twenty years, so they simply didn't know.
> Is this something which in the real world
> only applies to Jet aircraft with
> afterburners?
The theory applies equally well to both types, but arrived a little too late to make any difference to prop' fighters. It is my opinion that even had it been known, it would probably never have been of benefit. Flight sim pilots do many things that real pilots would never dream off... For us life is cheap (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
That doesn't stop us taking advantage of the knowledge now. But even in our crowded arena, full of pilots doing the damndest things, the opportunity is still quite rare.
2. Why does no other WW2 simulator allow this sort of tactic?
They do. I've used it effectively in three other online WWII simulations. Generally, I've only found it effective fighting real people flying similar aircraft.
> Is this the sort of tactic that, while
> possible, wasn't practical with real
> WW2-era airplanes?
I think so.
Badboy
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Just a simple exercise in AH:
1 - Pick up a 190A8 4x20 75% fuel.
2 - Go up with substained climb to 15k
3 - Initiate a full power WEP-ON dive to 10k
4 - Level the plane for a bit, check speed and go vertical.
5 - Check the altitude where you stall.
6 - Repeat the process 1000 more times.
7 - Calculate the average altitude of stall.
Now do it with the lighter 190A5.
Now do it with the much lighter Spit V.
Now do it with the lighter Spit IX.
Now do it with the heavier P47.
Now do it with Niki, well, better dont do any test with Niki ...
Now try to elaborate some exotic physic formulaes that explain those results. If you tested the nikki, your formulaes surely will be as much exotic as inovative.
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Originally posted by Badboy:
They were not simply unloading, and this is a valid and aerodynamically correct procedure. I believe the technique is part of current USAF tactical doctrine.
I've just submitted an article that explains how and why it works to SimHQ and I'll post the link as soon as it goes live.
I want to see that article, and I hope you have references on it.
I still want to know where the extra energy is coming from. During my private pilot training, when the engine quits, we were instructed to trim for best glide, not porpoise up and down to stretch the glide. The freight airlines don't porpoise to save fuel on those long transatlantic flights either (and I'm sure those pilots would LOVE to be able to do something mildly interesting during those long boring flights).
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http://www.simhq.com/simhq3/sims/air_combat/co-e_chase/ (http://www.simhq.com/simhq3/sims/air_combat/co-e_chase/)
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PS Badboy what I meant was that with thrust and drag in the picture, you don't get to turn all your PE into KE and vice versa.
PPS Nice article. I still don't think you will get a long term advantage with a prop plane if both planes start at maximum level speed. But it definitely works in the short term - I get into guns range against "faster" planes with my Seafire II this way all the time. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
[This message has been edited by funked (edited 02-02-2001).]
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Very cool! Thanks BadBoy!
So THAT is why this works. I use tactics like this in the Jug, but I never knew why they worked. I just marked it down to the Jug's tendancy to "work better" at high speed. I can't tell you how many times I have used a 0 G extension to get to 300 IAS or so, and then used a very gradual high speed climb in the Jug. It is one of the tricks to maintaining a good E position a plane like the P47. It's good to know why it works. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Badboy, I would LOVE to see that curve for the P47 in AH. I suspect the Jug would show a higher speed for that "most efficient" energy transfer point than many of the other planes in AH, but I may be wrong. It would be great to know of my instincts about the Jug are correct. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Lephturn - Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
"A pig is a jolly companion, Boar, sow, barrow, or gilt --
A pig is a pal, who'll boost your morale, Though mountains may topple and tilt.
When they've blackballed, bamboozled, and burned you, When they've turned on you, Tory and Whig,
Though you may be thrown over by Tabby and Rover, You'll never go wrong with a pig, a pig,
You'll never go wrong with a pig!" -- Thomas Pynchon, "Gravity's Rainbow"
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Hi Nuku,
> I still want to know where the extra
> energy is coming from.
The extra energy comes from using what you have more efficiently. I have always found this technique to be most useful against bandits who attempt a climbing extension. If they get separation and then do a maximum rate climb their prop will typically be working well below maximum efficiency, and their aircraft will also be far from its maximum aerodynamic efficiency (AoA for maximum L/D ratio) and those factors alone conspire against the extending pilot. The other reasons are explained in the article.
> During my private pilot training, when
> the engine quits, we were instructed
> to trim for best glide, not porpoise up
> and down to stretch the glide.
Absolutely!!!
IMPORTANT NOTICE
Nothing I have said has any influence on the engine out procedure for any aircraft. Please do not... I repeat..DO NOT modify your current practice! Nothing I have ever said anywhere should be interpreted in the context of engine out performance!!!
Please don't take offense at this, I just do it for fun. I enjoy helping folk to fly simulations better, and helping them to understand why the simulated aircraft behave the way they do. I have no pretensions about the way any of that translates to the real world.
However, I get nervous when folk who fly real aircraft misinterpret my words and relate them erroneously to a potentially dangerous situation! But I'm sure you don't fly as carelessly as you read, so I guess everything is ok (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Take care!
Badboy
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Originally posted by Lephturn:
Badboy, I would LOVE to see that curve for the P47 in AH. I suspect the Jug would show a higher speed for that "most efficient" energy transfer point than many of the other planes in AH, but I may be wrong. It would be great to know of my instincts about the Jug are correct.
Thanks for the kind words...
Given time, I hope to analyse all of the aircraft in AH. It is currently my favorite sim! I believe your suspicions about the Jug are correct! Higher wing loaded aircraft tend to have their V speed numbers pushed up. If I do an analysis of the P47, what would you say would be the most interesting opponent to compare it with?
Badboy
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Hmmm good question.
At first glance I would say the F4U, but I'm thinking they are too similar. With the same engine and many similar traits, it may not be a very good comparison. They may end up being very close in this regard, so it may not illustrate very much at all.
I think the George would be a better choice. The N1K2 is one of the most populular planes in the game, so that puts it in contention. It is also a plane that many folks have trouble with as an opponent, so more information may help. The George is also the opposite of the Jug in many ways, (being a good accelerator but not so good at maintaining E at high speed) and so it should show more difference in the charts and demonstrate the theory better. The George is faily representative of the lighter more TnB type planes in the arena, so this would possibly help make the information more applicable.
It sure would help to know the critical numbers for using energy most efficiently in the P47. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) There are not many advantages we Jug pilots can exploit, so we need to maximize every tiny advantage we can!
Thanks Badboy!
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Lephturn - Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
"A pig is a jolly companion, Boar, sow, barrow, or gilt --
A pig is a pal, who'll boost your morale, Though mountains may topple and tilt.
When they've blackballed, bamboozled, and burned you, When they've turned on you, Tory and Whig,
Though you may be thrown over by Tabby and Rover, You'll never go wrong with a pig, a pig,
You'll never go wrong with a pig!" -- Thomas Pynchon, "Gravity's Rainbow"
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The article explains very well the physics of why a pursuer is able to get into guns range, but still doesn't detail how this advantage can be done more than once to *constantly* close the range.
In Shaw's "Fighter Combat", Figure A-7 shows that while Turbojets gain thrust with increasing airspeed, props LOSE thrust.
The green lines on your Es/Ps diagram (known a H-M Diagram, or "altitude-mach" diagram) are lines of constant "specific energy" (effectively PE+KE). In a frictionless closed system, any aircraft (or rock for that matter) follows those lines up and down, trading altitude for airspeed. In my tail-chase scenario, the attacker, as he dives, moves down the green line, going faster, but losing altitude. As he climbs back up, he loses airspeed and gets back to altitude exactly where he started.
In order to jump from one green line to another green line, you need to pump energy into the system. In the real-world, drag is constantly pulling you left into the lower green lines, and thrust helps you move right to the next line (or at least, helps you stay on your current line).
The blue lines on the diagram are lines of "specific excess power", which is a mixture of KE (zoom energy), thrust (raw extra energy), weight, and drag. The blue lines as overlaid on your diagram match the thrust increases with airspeed that turbine engines get at altitude. Prop engines however, don't have the "molar tooth" look: the blue lines for a WWII fighter go up and then slide constantly down (pretty steeply, like a parabola squished to the left).
In order to jump from one green line to another green line, your combination of airspeed and altitude must land on a blue line with a positive quantity. Unfortunately, the blue parametric lines in your diagram are not labeled, so I can't tell exactly where you can jump to the next green line. Actually, I don't know how you've overlaid those blue lines because in the tail-chase scenario, the attacker's Ps is zero (steady-state, thrust = drag, level flight). So a blue line through point A in the diagram would be the "0" Ps line, aka as the maximum all-balls out level speed at a particular altitude (or max-performance envelope).
All blue lines OUTSIDE the 0 Ps line are negative, meaning the aircraft CANNOT jump to the next green line. Blue lines INSIDE of the 0 Ps line mean the aircraft can move to the next highest green line (by accelerating level, or climbing).
I think this diagram is deceptive in that it shows the aircraft well inside its performance envelope. I think Ps=0 is the outermost blue line in the diagram.
Diving to gain energy works for JET fighters because if you were already at Ps=0 at the edge of the last blue line, you could follow the green line across the "dip" and into the wave of increasing blue lines to go even faster.
A prop aircraft, as I said before, doesn't have this cusp, and the Ps countours are parabolic, and not as flattened at the top. In the tail-chase scenario, the attacker is riding the Ps=0 line, and if he dives, he'll blow right outside the envelopes and never re-enter positive Ps territory to catch me.
That's where I'm confused.
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Hmmm.
I'm not going to talk about the diagrams, because they are not specific for a prop plane and I think it will confuse the issue for me. Badboy can explain the math. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Lets look at it in a situation. You and I are in P47's, roughly co E in a tail chase. We are both at 10k and 200 IAS. We both have excess power, since our planes will both do about 375 MPH at this altitude in WEP top speed. The point is that the Jug and it's prop will more efficiently convert it's extra power into altitude or speed when it is moving faster than 200. Lets just assume for a minute that the magic number is 350 Mph, WAG. (Wild Assed Guess) So as you stay level and accelerate you are transferring your excess power into energy at low efficiency. I use a 0G dive to get up around 300, and then zoom gently back up to your altitude. The closer my plane gets to the 350 number, the more efficiently I am converting my excess power into speed or altitude. You are still struggling along at a lower speed that is even less efficient, so you are converting that excess power to energy at much lower rate than I am. I am gaining energy on you, mostly in the form of speed, and closing on you.
Now lets say I have done this once, but I am not in guns range. Now I am not at my most efficient speed anymore after the zoom, lets say I fell back down to 275. I again use a shallow 0G dive to accelerate, this time to 350, and then begin a gentle zoom back up to your altitude. At this point I am now flying very close to the most efficient speed at which the Jug converts excess power into speed or altitude. You have not accelerated as quickly, since you have been flying at a slower speed and hence a less efficient speed for converting your excess power into energy in the form of speed or altitude. I can keep doing this and keep gaining energy on you as long as you are not at your most efficient speed for converting excess power to energy. Once you reach 350 Mph at 10,000 feet, you are now converting your excess power into energy at the most efficient rate, so I can't make this trick work anymore. What now?
Ok, now lets say I have done this twice, and gained on you, but not quite enough yet. You have, by this time, reached your top level speed at 10k of 375 MPH. Now, that number is over your most efficient conversion speed of 350. By the same logic I should now be able to zoom gently at 350 Mph and gain E on you. I will fall behind because of speed at first, but at this point you are not gaining energy, and I am. If I climb at 350 while you run at 375 level (you have no excess power at this point), I will be gaining energy in the form of altitude. If I have time, I should now be able to use another 0G dive to accelerate OVER 375 Mph and start catching you again. Now this may not work as well due to higher drag and what not, but I am trying to illustrate the point. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Now, at the time where you reached 350 Mph, your most efficient speed for converting excess power into energy... you could have held me at bay indefinately. If you simply set auto-trim for speed at 350 Mph and let the plane climb at that speed, there is nothing I can do. I am screwed, and no matter what I do I will not be able to gain energy on you. You will have to turn, speed up, or slow down in order for me to have any advantage to exploit.
The trick is, how do we find out what that number is? Badboy, can you suggest a test method that might allow us to find that number? If you know the speed at which your plane converts excess power into energy at the most efficient rate for a give altitude, you can maximize your performance and either close on a similar bogey who is not maximizing his plane, or keep out of the guns range of somebody who is. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Clear as mud? (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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Lephturn - Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
"A pig is a jolly companion, Boar, sow, barrow, or gilt --
A pig is a pal, who'll boost your morale, Though mountains may topple and tilt.
When they've blackballed, bamboozled, and burned you, When they've turned on you, Tory and Whig,
Though you may be thrown over by Tabby and Rover, You'll never go wrong with a pig, a pig,
You'll never go wrong with a pig!" -- Thomas Pynchon, "Gravity's Rainbow"
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"Clear as mud?"
Clear as all get out (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) This topic has helped me understand some behavior I'd previously thought of as odd.
Thanks guys! I appreciate all these posts and th efforts by all to help explain what is going on.
-Westy
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Originally posted by Lephturn:
Lets look at it in a situation. You and I are in P47's, roughly co E in a tail chase. We are both at 10k and 200 IAS.
The situation I started this thread with was NOT the start of the chase, where acceleration counts. That, I understand, and is the crux of Badboy's argument (especially when the defender is climbing below efficiency, and the attacker dips to hit his most efficient speed). The bottom line is that the attacker is simply outaccelerating the defender.
It's at *steady state* when BOTH aircraft are at maximum speed (Ps=0 curve in the diagram). In your example, pursuer and attacker have already stabilizied level at 375MPH and the attacker is out of range. Now what?
By both your efficiency logic and the HM diagram, going any faster causes you to LOSE efficiency/energy. Going straight at 375MPH (the defender) is more efficient than going into a dive at 400MPH (the attacker). Prop efficiency drops at higher speeds (turbojet increases so this would work as Badboy states). By the efficiency logic, the pursuer should CLIMB at WAG speed (350MPH), then dive to catch the defender.
Stated another way, I think the distance gained in the dive above max efficiency, is lost during the climb AT max efficiency. During the dive, thrust is dropping, but drag is increasing. All that energy is pfffht.. gone. At the nadir point, as the attacker pulls up all the extra KE goes pack to PE, and while he's above 350, parasitic drag sucks still more energy out until thrust and drag two balance at 350MPH. By the time he gets back to the defender's altitude, I think he's at a deficit.
As I stated before, with prop planes, the attacker will dive right outside his performance envelope: he will generate less thrust, and parasitic drag will be greater than it was during level flight, so all the PE he converted to KE will get sucked right out, and he'll lose in the end.
The dive-zoom tactic is for a short-term snap-shot and works BEFORE both aircraft have hit their Ps=0 (max speed) points.
I'm still not convinced that once both aircraft have finished accelerating (level) that the pursuer can do anything to catch the defender if in a PROP plane.
[This message has been edited by Nuku (edited 02-03-2001).]
[This message has been edited by Nuku (edited 02-03-2001).]
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Hi Nuku
> The article explains very well the physics
> of why a pursuer is able to get into guns
> range, but still doesn't detail how
> this advantage can be done more than once
> to *constantly* close the range.
Optimal application does not involve repeating the procedure. It only needs to be repeated if the climb is started too soon, or too steeply. However, it still works when repeated because you are in effect oscillating between an optimum condition, and one only as bad as your opponents. So your energy transfer is better some of the time. It still works, but takes a little longer to get the kill.
> In Shaw's "Fighter Combat", Figure A-7
> shows that while Turbojets gain thrust >with increasing airspeed, props LOSE thrust.
Correct, but considering thrust alone doesn’t solve the problem. Because we are more interested in the maximum rate of energy transfer it is better to think in terms of efficiency, not just thrust. Prop’s produce less thrust as they get faster, but they also become more efficient, up to a point. Also the aerodynamic efficiency of the aircraft improves as the speed increases (until you reach the AoA for the best L/D ratio) and of course as the altitude increases the drag drops. It is a combination of all those factors, combined with their variation with speed, that is being represented in the diagram.
If it were only thrust that mattered, the Jet would want to get as fast as possible, and the Prop’ would be better off stationary! Neither of which is the correct thing to do and the theory wouldn’t work in either case.
> in the tail-chase scenario, the attacker's
> Ps is zero (steady-state, thrust = drag,
>level flight).
I never made the assumption that the fight began from zero Ps because it almost never does.
> I think this diagram is deceptive in that
> it shows the aircraft well inside its
> performance envelope.
The aircraft in this scenario never leave the envelope, that’s not deceptive, it is perfectly correct. The aircraft do not leave the envelope at any stage of the engagement I described.
> A prop aircraft, as I said before, doesn't
> have this cusp, and the Ps countours are
> parabolic, and not as flattened at
> the top.
That is correct, but the prop’ curves still yield a best energy transfer solution. They do so because the highest energy state along any Ps curve is the point where they are tangent to the Es curves and that is just as true for a prop’ fighter as it is for a jet. Of course the solution is different, but a solution all the same.
To imagine what it would like, picture the prop curve in Figure A-13 of shaw and imagine Es curves superimposed on them. Now the best energy transfer will occur at points where they are tangent to each other. Yes, it will look different, but the solution will be just as valid.
> In the tail-chase scenario, the attacker
> is riding the Ps=0 line, and if he dives,
> he'll blow right outside the envelopes and
> never re-enter positive Ps territory to
> catch me.
The attacker doesn’t start at Ps=0 and should only dive to his best energy transfer speed. Of course if he dives right out of the envelope, he will almost certainly have lost it completely.
> Prop efficiency drops at higher speeds
> (turbojet increases so this would work
> as Badboy states)
Prop efficiency increases with speed, up to a point. It drops when Mach effects begin to have an influence, but the best energy transfer speed is well below that point.
> As I stated before, with prop planes, the
> attacker will dive right outside his
> performance envelope:
He should only dive until he gets to his best energy transfer speed.
> I'm still not convinced that once both
> aircraft have finished accelerating
>(level) that the pursuer can do anything
> to catch the defender if in a PROP plane.
Correct. The fight will have been neutralized once both aircraft have reached top speed at critical altitude. Whatever separation they have at that point is what they are stuck with. That’s the same for jets, the main difference being that they end up a lot higher, often somewhere just above 36000ft.
Hope that helps.
Badboy
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Originally posted by Lephturn:
The trick is, how do we find out what that number is? Badboy, can you suggest a test method that might allow us to find that number? If you know the speed at which your plane converts excess power into energy at the most efficient rate for a give altitude, you can maximize your performance and either close on a similar bogey who is not maximizing his plane, or keep out of the guns range of somebody who is. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
The best way is to actually produce the curves for it. I can do that, and I already have the data for quite a few of the AH aircraft. What I am short of right now is time!! As well as my full time teaching job, I'm on the point of signing the contract for another strategy guide. I just wish I didn't need to sleep (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
It may take a little while, but I will come up with the goods eventually... I promise!
Badboy
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Hmm, i can see this working for jets (after all, delta wings aren't very efficient at low speeds, so speeding up would lower drag, thus netting you energy), but I'm not sure why it works in prop fighters. Is the "magic" speed here the speed above which the prop starts "braking" the plane, or are we talking about engine performance at various alts only?
Rickenbacker
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Rickenbacker,
I think this has a lot to do with aerodynamic efficiency of the airframe in combination with the efficiency of the prop at various speeds. I think the combination of those two factors lead to this effect. What I mean is, I think your prop/airframe combination is better at turning excess power into energy (alt or speed) at higher speeds. The result is that you can increase your energy faster when the plane is at a higher speed. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
The efficiency of the engine at different altitudes is not really the issue here IMHO, although it certainly does factor into the overall equasion. Some planes get a nice boost of power when the second stage turbo kicks in at a certain altitude, so a smart pilot will factor that knowledge into the equasion as well. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Here is something for you to try, just to see the effect. This is something I was advised to do back in WB 1.01 by my amazing squad mates. Take a Pony, and set your auto-trim for speed to 325. Now, when you get a co-e enemy chasing you, just engage auto-speed and watch what happens. The Pony will out-climb many "better climbing" airplanes if it climbs at that speed. I use the same trick in the Jug. Granted, this isn't maximum "climb", as my altitude is not going to go up that fast; however, my overall energy state (altitude or Potential Energy/PE and speed or Kinetic Energy/KE combined) will increase at a higher rate than in a low speed climb.
Badboy,
Thanks for all the great work! I look forward to seeing those numbers when you get them done. The AH community thanks you!
------------------
Lephturn - Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
"A pig is a jolly companion, Boar, sow, barrow, or gilt --
A pig is a pal, who'll boost your morale, Though mountains may topple and tilt.
When they've blackballed, bamboozled, and burned you, When they've turned on you, Tory and Whig,
Though you may be thrown over by Tabby and Rover, You'll never go wrong with a pig, a pig,
You'll never go wrong with a pig!" -- Thomas Pynchon, "Gravity's Rainbow"
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<punt> This deserves to be higher up on the list than lots of those other posts full of... well... stuff. <G>
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Yeah I agree... That was a great article Badboy. I'm looking forward to seeing it applied to AH. Leph's Jug/Niki comparison suggestion would be very interesting.
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I have a better one. Try turning a nik with a zeke. Then try to run. No wep, and notoriously slow, the zeke will catch you in the short dash.
This drove me crazy after they cut the acceleration on the nik. Finally it dawned on me, the zeke wasn't bleeding E in the tight turn. I was. Solution. Trim the nik through the turn. These aren't real planes, trim makes a huge difference, in the game.
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Yeah, the Zeke is "slow", but it is "quick". (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) The Zeke's top speed is not very high, but it is very light. Because of it's light weight it is actually a pretty good accelerator from low speeds. Don't try to run from it from a low speed start, or it WILL catch you in the short term. Any Hog or Jug driver who gets slow with a Zeke better have some separation before trying to dive away! Although the Zeke will perform badly at high speed, the short-term acceleration is still pretty good, and it will catch the heavier planes for a short time.
Hey easymo... are you using combat trim? Just wondering. I think the combat trim negates much of the advantage that the manual trim tricks used to give you, but maybe I'm wrong.
------------------
Lephturn - Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
"A pig is a jolly companion, Boar, sow, barrow, or gilt --
A pig is a pal, who'll boost your morale, Though mountains may topple and tilt.
When they've blackballed, bamboozled, and burned you, When they've turned on you, Tory and Whig,
Though you may be thrown over by Tabby and Rover, You'll never go wrong with a pig, a pig,
You'll never go wrong with a pig!" -- Thomas Pynchon, "Gravity's Rainbow"
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Leph. Come into H2H we will find out (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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easymo,
I don't get much personal time to spend online... so when I do get it I tend to spend it in the main. Between my very busy job and my duties as a trainer, I'm a busy boy. However, I have been meaning to check out H2H sometime just so I can answer questions about it. I'll see if I can find you around.
Still, if you have a feeling one way or the other, why don't you post it? Anybody else have an opinion on manual vs. combat trim?
------------------
Lephturn - Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
"A pig is a jolly companion, Boar, sow, barrow, or gilt --
A pig is a pal, who'll boost your morale, Though mountains may topple and tilt.
When they've blackballed, bamboozled, and burned you, When they've turned on you, Tory and Whig,
Though you may be thrown over by Tabby and Rover, You'll never go wrong with a pig, a pig,
You'll never go wrong with a pig!" -- Thomas Pynchon, "Gravity's Rainbow"
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FWIW I use manual trim.
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Combat trim here. (Trim should not affect anything except stick forces and therefore it should not change E retention or turn performance.)
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So the quickest route between two co-alt points in the air is not a straight line ?
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No point in using manual trim when you have combat trim that does the job for you in 2 keypress and you don't have to keep it ON.
Basically, I hit combat trim when I need my aircraft to be trimmed, and hit it again and again and again and again, but never leave it on.
------------------
Nath_____
9./JG 54 "Grünherz"
(http://pobox2.zyan.com/~nath/haha.jpg)
A captured Bolshevik pilot once stated, "In battle, the fighters with the green hearts are generally in the minority. But when they're there, things realy heat up. They're all aces!"
[This message has been edited by Nath-BDP (edited 02-05-2001).]
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Seems that plane 2 (the chaser) is faster during both the down and up line. Could the trade-off, then, be that extra speed gained outweighs the angle-of-flight penalty? Not just a question of E, but one of simple geometry? Maybe the trick is to gain the speed during the descent, but to set the angle of the ascent back to the beginning altitude to arrive back at the original airspeed and altitude immediately after leveling out?
[This message has been edited by Biggles (edited 02-05-2001).]
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Interesting stuff Badboy. I found this works in the Tiffie really well, although until now hadn't figured out why.
Going into even a co-alt fight I unload 2k-5k worth of alt to crank the tiffie up and always seem to come out better. Going co-alt flat never seems to work well.
IE - in a co-alt fight with a yak if i merge level, post merge the yak is always better off. If I dive about 20 degrees nose down before the merge to grab speed, and the yak does the same, I always come out better off (eg, if we both go vertical post merge, in the first instance the yak usually has me, in the second I have him).
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Originally posted by Suave1:
So the quickest route between two co-alt points in the air is not a straight line ?
Short answer… No it isn’t.
Of course the shortest route is a straight line, but it isn’t always the quickest (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
If you wanted to get from point A at 5000ft to point B 200 miles away at the same altitude, in the shortest possible time, it would make sense to climb to an altitude where your true airspeed is faster. It follows that you would want to get to that altitude with as much energy as possible, in the shortest time possible, and a best energy transfer climb would help. If you were starting from low speed, it would also pay to accelerate as quickly as possible, and that means unloading. So the quickest route between those two co-alt points could well involve an initial dive and climb schedule.
I guess everyone has heard the phrase:
“The shortest distance between two points is a straight line”?
That phrase works nicely for two dimensional geometry, but when you get into 3D, that phrase can sting you in the tail.
Take a look at the box in this diagram…
(http://www.netcomuk.co.uk/~badboy/PDF/box.jpg)
There is a point at the center of each end of the box, 1” up from the bottom at one end, and 1” down from the top at the other. To get from one end to the other you must remain in contact with the surface of the box. With that in mind, what is the shortest distance from one point to the other?
Now, when I see the first correct answer, I’ll explain what that has to do with air combat (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Badboy
[This message has been edited by Badboy (edited 02-05-2001).]
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39.........
[This message has been edited by SKurj (edited 02-05-2001).]
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Originally posted by SKurj:
39.........
Sorry Skurj, I had it the wrong way up (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Refresh the page and you should see the new one.
Badboy
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41.1?
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I'll try 45, for kicks.
Jay.
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Hi,
Jay, that's what most folk would say, but there is a shorter route.
Pinner, the answer is even less than that.
Badboy
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Lotta misinformation in this thread.
Badboy's article, and pretty diagrams present a very nice theoretical fiction that simply does not translate into real life.
Is it possible to use the technique outlined to close on a fleeing opponent? Not really.
What would it take to make this technique work? A perfectly frictionless environment. With perfect interception of all datum points and then only if it were possible to perfectly convert from one Energy state (Kinetic Energy) to the other Energy state (Potential Energy or altitude), with no losses at any point in the procedure.
Friction (Drag) and varying Ps states throughout insure that the theory never becomes reality.
First you have to burn some E converting from straight flight to the dive (which can be neither too shallow nor too steep) and then you have to burn more E converting from the dive into the climb (which also has to be at only one perfect angle). All the while Drag is more than negating every Erg you gain in the dive (remember Drag increases with the square of the speed, not linearly - the difference in Drag between velocities of 500 fps and 525 fps is 25625 x Coefficient of Drag).
If you're very, very good and very very clean, you can minimize the Energy lost during the maneuver (zero G noseover at both ends), but there will always be an Energy loss when merely returning to your starting altitude.
The maneuver Badboy describes is useful for one thing and one thing only... minimum time to get from altitude A to altitude B with maximal energy gain at arrival.
When altitude A equals altitude B, such gyrations are only something to do to pass the time.
If you somehow manage to use something similar to catch a fleeing bandit, it wasn't because you did anything right (you didn't), but because the bad guy made even bigger mistakes than you did.
If the sim you're flying models things differently, there is something fundamentally wrong with the sim.
Dwarf
PS. If you still want to believe in Badboy's fantasy, I've got a Perpetual Motion Machine I'm willing to sell for a really reasonable price... considering.
[This message has been edited by Dwarf (edited 02-06-2001).]
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Ok guys,
The way to figure out the quickest route around that container is to open it up and lay it out flat, in 2D where we can rely on the fact that the shortest distance between two points is a straight line. If we do that it looks like this:
(http://www.netcomuk.co.uk/~badboy/PDF/box-2.jpg)
You can see that it will fold up into the original container, and that the shortest route is exactly 40.
If you draw that line while it is flat and fold it back up, the shortest route looks like this:
(http://www.netcomuk.co.uk/~badboy/PDF/box-3.jpg)
You need to go diagonally to the bottom, cut across the corner, go diagonally up the side to the top, across the top and then diagonally down the far end. That's the shortest route and it isn't a straight line.
What has all that got to do with Air Combat?
Ok try to imagine this... Replace that container with the energy egg (That's the egg shaped surface that aircraft maneuver on)and replace the points on that container by points on the energy egg starting where you are, and ending where you want to be. Does the shape of route in that last problem bring the high yo-yo to mind? Could that be why it works so well?
(http://www.netcomuk.co.uk/~badboy/PDF/egg.jpg)
Of course, with two moving aircraft we can't just measure distance anymore, because the situation is very dynamic. When I can produce a proof for the energy egg as convincing as the one for the rectangular container, it will make a nice article... until then it is just something interesting to think (or argue) about (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Badboy
[This message has been edited by Badboy (edited 02-06-2001).]
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Nice example. Well illustrated.
What do either it or the Hi Yo-Yo have to do with a situation where the bogey is not maneuvering and you have no overtake speed?
(Which IS the situation posed at the beginning of this thread)
Dwarf
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Originally posted by Dwarf:
Nice example. Well illustrated.
Hi Dwarf,
Thanks, and Welcome to the boards!
What do either it or the Hi Yo-Yo have to do with a situation where the bogey is not maneuvering and you have no overtake speed?
(Which IS the situation posed at the beginning of this thread)
Dwarf
The two situations are really only very loosely related. I was responding to the point someone made about the shortest distance between two points. It was a digression.
When you say:
Start with Nuku's original proposition:
2 aircraft travelling the same direction at max velocity. Aircraft B is out of guns range of aircraft A, but has no overtake speed. Therefore aircraft B is at a state where Ps = 0. Its engine/prop/airframe is maxed out.
In that situation, of course I agree. I also agreed with Nuku when he said it. I didn't cover the "Both aircraft at max speed" situation, because although some fights may well end up there, they don't generally start there. However, that point was covered earlier in the thread.
I also believe that the situation Nuku described did not start that way either, regardless of his description. If it had started that way, it probably wouldn't have ended the way it did, as you rightly point out.
Badboy
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Originally posted by Badboy:
I also believe that the situation Nuku described did not start that way either, regardless of his description. If it had started that way, it probably wouldn't have ended the way it did, as you rightly point out.
Badboy
OK. Very glad we agree on the main point.
Thanks for your clarification.
The article on EM diagrams and how you use them is the best I've seen on that subject to date. I join everybody else in offering my congratulations and my thanks.
Dwarf
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Nuku -
Here's some additional possibilities that may explain what happened.
1. Netlag - you may have encountered a situation where, while it looked to you like the range had stabilized, he really still had some overtake. The defender's view of things is always the least reliable.
2. Trim - while you believed you had the plane cleaned up as best it could be, you might have been just enough out-of-trim that you couldn't reach your true top speed while he could.
3. Weight - he may have been just enough lighter than you were that he could get an extra couple mph out of his airframe.
If he had a slight bit of overtake or a tiny bit higher top speed, he could exploit that by diving slightly to help him close.
Or it could be something else entirely, including other things that have been mentioned.
Dwarf
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Badboy the second picture in your article is for SUPERSONIC JETS!!! It´s the typical curve for a supersonic jet, how to build up E. The dive is used (following the green line) to break through the sound barrier ! With a dive you break very fast through this barrier, and it is at the end faster to do this dive and then begin a supersonic climb.
First from sealevel a "normal" climb to 30-40k, until the macheffect shows up, then the dive, then the supersonic climb.
A 0G dive can bring you imo only ONCE nearer to an identical aircraft. Don´t forget: you push your stick forward (0G) and you begin a dive. But sooner or later you have to PULL to bring up your nose again. That means you MUST fly now a manoevre with more than 1G! And during this manoevre you loose the advantage that you got with 0G.
The flight path is longer
Drag increases with more speed (when you´re flying faster than a special speed, which is different for every aircraft (often close to best climbing speed))
During manoevering you have to deflect your control surfaces > drag
Diving means flying lower > higher air pressure > more drag
Thrust decreases with more speed for a propeller driven plane
0G advantage is nullified during pullout (1.xxG pullout)
Near topspeed the induced drag is very low compared to zero lift drag. The advantage of a 0G dive is not very big near topspeed. That is different if you start your dive from low speeds.
It is possible that a dive allow you to shoot from a closer distance, but only if you begin to shoot from a lower position. If you return to the same altitude your E-Status should be worse imo.
niklas
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Hello all,
Great posts being put up on this thread... but with all this knowledge of physics and whatnot, we should be nicknamed Einstein and be used plasma engines to zoom to the moon every day.
One thing to keep in mind is that this is a physics engine that is very different. The real world is based on simple rules that govern most all movement and behavior (ie conservation of energy and other laws). The rules of the AH physics are bent and tweaked to improve playability and game balance.
But if real life physics were applied, the situation stated at the beginning probably could have been accomplished. Conservation of energy.. ie energy is not destroyed or created, it is only converted into different forms. Say the pursuing pilot puts his a/c into a slight dive to gain some sort of closure rate. He is trading alt for speed. In a matter of time, he will end up within the desired range of his opponent, yet at a lower altitude. Should he pull up and trade speed for altitude, he should not end up in the starting position due to continuing thrust output. He simply cannot trade his kinetic energy acquired from the dive back in for his exact original potential energy. Energy is lost with the friction of the air (aka drag) over the aircraft. The aircraft's thrust is making the plane constantly accelerate. If there were no acceleration from thrust (terminal velocity achieved and no deceleration) the net energy lost would equal the net energy gained. In otherwords, no accel, and no difference in PE and KE ratio as the pilot dives and climbs. AH's engine is tweaked to allow energy to be conserved much more efficiently than a more realistic flight model would. The KE is not converted properly as PE is obtained. IN the end, you end up with more KE as you regain your original PE. Crazy? Yes. Almost seems as if AH has found the answer to perpetual motion!
If this scenerio were to take place in a frictionless environment, small amounts of energy would not be lost. Plus, without any friction the aircrafts would be constantly accelerating. Anyway, excluding thrust and including a constant velocity.. if this maneuver of trading PE for KE, and later KE for PE, was to be executed, the object would end up with no change in distance from when it started.
In the longrun, it all depends on how well you can determine how well you can conserve energy in your aircraft. If you know the simple, basic rules of physics, you can use that to build your knowledge and understanding of most everything.. umm.. physical.
These are just my thoughts, please don't blast me if I'm wrong about any of it (http://bbs.hitechcreations.com/smf/Smileys/default/tongue.gif), thanks.
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-=///Octavius\\\=-
(aka Executor)
VMF-323 "Death Rattlers"
MAG-33
Maz203@aol.com
[This message has been edited by Octavius (edited 02-15-2001).]
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Er... My $.02
Badboy is pretty much correct. To use what he's talking about, you either have to have a zillion hours in the plane and be VERY observant, or you need the Ps charts for all conditions (fuel weight, altitude, ext. stores, etc etc.) It doesn't apply "only to jets", the curves just look a bit different thats all.
In practice, you use the charts to get some rules of thumb, and attempt to use those areas of the chart where you have the advantage. Realize that all it takes is for you to mis-assess your opponent's energy level a little bit, and all your planning did was make you die more intelligently.
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eagl <squealing Pigs> BYA
Oink Oink To War!!!
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So the quickest route between two co-alt points is the shortest distance afterall . Not a roller coaster track . Octavius nailed it .
[This message has been edited by Suave1 (edited 02-17-2001).]
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Suave1,
Everything I've said is correct. If you read the previous posts carefully, you will see that. Also I believe that eagl is agreeing with me.
I simply can't address the faulty reasoning from other posters, there are just so many issues, it's overwhelming.
However, this thread was continued here:
http://bbs.hitechcreations.com/smf/Smileys/default/Forum2/HTML/000611.html (http://bbs.hitechcreations.com/smf/Smileys/default/Forum2/HTML/000611.html)
That speaks for itself.
At the risk of repeating myself, the facts are:
1) It is possible to draw Ps (P sub s) curves for every aircraft, regardless of type.
2) It is possible to superimpose those curve onto Es (E sub s) curve.
3) The maximum energy state along any Ps curve is where it is tangent to the Es curve.
4) Such a point will always exist, regardless of aircraft type.
5) That point will lie somewhere between the best climb speed and the top speed for that alt.
6) The speed at that point yields the best energy transfer, call it V sub t or just Vt.
7) Best energy transfer gives you maximum energy gain in minimum time.
8) Every powered aircraft, regardless of type has such a Vt speed.
9) It can be used to gain an energy/time advantage over an aircraft that doesn’t use it.
10) If you start a fight below that speed energy transfer will be optimised by diving to it at 0g.
Those are facts!
The only remaining question is what are the actual Vt speeds for each aircraft. That, in my opinion, is the last remaining piece of the jigsaw. Unfortunately my current schedule means it may be a while before I can return to that problem.
Meanwhile The simple fact is that it does work. A lot of people have already confirmed it and have been doing it for a long time already. It is also rather easy to confirm. It doesn't just work in Aces High, it also works in Warbirds, Air Warrior, MSCFS, and EAW... Infact almost every other WWII sim since Chuck Yeager's Air Combat.
The Aerodynamic theory explained above predicts that it works, and the flight models of most of the sim's that replicate it are not so shabby that something that major would be wrong.
Lastly, on your question regarding the shortest distance between two points... After reading these boards I could easily believe that the shortest distance between some folk's brains and their mouths is via their arse, and I agree that would disprove my theory (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Despite that, I believe the example I posted previously with the box and the energy egg is sound. As yet, I haven't seen a better explanation for why the yo-yo works so effectively... unless of course you intend to post one?
Badboy
[This message has been edited by Badboy (edited 02-17-2001).]
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Originally posted by Dwarf:
What do either it or the Hi Yo-Yo have to do with a situation where the bogey is not maneuvering and you have no overtake speed?
(Which IS the situation posed at the beginning of this thread)
Dwarf
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Originally posted by Dwarf:
Badboy was right and I was wrong.
Congratulations, Badboy. Well done.
Dwarf
[This message has been edited by Badboy (edited 02-18-2001).]
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[This message has been edited by Jekyll (edited 02-18-2001).]
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That's quoting Dwarf out of context, in his thread he's just saying that it works in AH. What he did would also work in real life, if the plane was not at max speed for the alt that it was at prior to the dive. If it was at max speed and dove, and climbed slowly back to that alt, shouldn't the speed that it had accumulated ebb as the plane would decelerate back to it's max speed for that alt ? What I disagree with is that a plane can catch up from kilometers behind to another plane of the same type that is going max speed co-alt, by using this method .
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Originally posted by Suave1:
That's quoting Dwarf out of context, in his thread he's just saying that it works in AH.
That's not out of context, it is the main point of the discussion! I will concede that it was probably not worth quoting... After all, the only thing remarkable about Dwarf's posts was that he was able to contradict himself faster than I could respond.
What I disagree with is that a plane can catch up from kilometers behind to another plane of the same type that is going max speed co-alt, by using this method .
That point has been made several times in several threads, and I agree with it. I've never said otherwise, accept to clarify the fact that there is only one speed and one altitude in which it is strictly true. That is when the two aircraft are at their top speed close to their critical altitude. A very unlikely situation for an engagement to begin, don't you think?
If the aircraft are above that altitude then an initial dive to critical altitude is best. Below that altitude it is better to climb at the best energy transfer speed to an altitude where you can continue the chase with a higher true airspeed than your opponent. Which brings us to the point that if you begin to do that from a speed below best energy transfer speed, you can get to it as quickly as possible at zero g. Which of course is exactly where we started!
Lastly please consider this... I'm amazed at the number of people willing to claim that a thing is wrong, simply because they don't understand it! I just wonder how many more will jump on the bandwagon?
Badboy
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Badboy, you always say dive to maximum energy transfer speed.
Do you know the typcial max.e.tspeed for a WW2 prop fighter? Often somewhere between 130-180mph IAS! You really don´t need to DIVE to this speed. If you come out of a sustained turn you´re very close to this speed, maybe your speed is even higher!
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Originally posted by niklas:
Badboy, you always say dive to maximum energy transfer speed.
Obviously you should only dive to that speed if you are below it. If you are already at or above that speed, of course you don't need to dive. I'm sure many folk would have missed that point, thank you for clarifying it.
Do you know the typcial max.e.tspeed for a WW2 prop fighter?
When I have the time I will produce the "Energy Transfer" diagrams for the AH aircraft and post them along with the "Energy Maneuverability" diagrams. When I have that information, I will also revisit my article and bring it up to date. Of course I will take the opportunity to clarify many of the misunderstandings expressed in these threads at that time.
Meanwhile, if you already have that information, perhaps you will post it? If not, I see no point in pursuing this discussion until such time as the actual AH data is available.
Badboy
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Originally posted by Badboy:
When I have the time I will produce the "Energy Transfer" diagrams for the AH aircraft and post them along with the "Energy Maneuverability" diagrams. When I have that information, I will also revisit my article and bring it up to date. Of course I will take the opportunity to clarify many of the misunderstandings expressed in these threads at that time.
Meanwhile, if you already have that information, perhaps you will post it? If not, I see no point in pursuing this discussion until such time as the actual AH data is available.
Badboy
Badboy,
I just came accross this thread by way of your article, so forgive me for beating the poor old nag.
I didn't read everyone's input here, but I caught most of it, and read all of yours (I think).
The one thing you keep coming back to is that you will chart the AC in Aces High.
When are you going to contact Piper, Beech, Northrop, NASA etc. and get some data on real planes.
This is after all, a simulator of WW2 aircraft, no?
The entire discussion and the accusations that you must have cheated are based on the real feeling that we all get from the science we were taught in school and our experiences in life.
The point to be made here is that Flight Modeling may or may not be correct. If we want Simulated realism, then we have to proof things against real occurrances.
Your P/E diagram is nice, and I understand the thought, but I think there is something missing.
When the plane dives, power and energy are both increased. Easy enough.
Now that the power is at a higher state, the plane can cover more distance in a shorter time. Also easy.
Understanding also that by diving, the distance covered is already greater than that of the plane being persued.
Now what happens and I think what you lose in your theory, is that during the climb, you are adding even more distance, Gravitational effect, and burning off that power that you just gained.
I understand the concept in Jet aircraft because the turbine engine creates more power due to the "Free" compression of gasses that is made by the extra speed. This is one of the basic functions of a turbine engine. The limit of power on any turbine is it's own ability to withstand the mechanical stress.
Piston driven engines however suffer the opposite effect at some point. As you increase RPMs, you will come to a point where the power curve will drop dramatically!
Superchargers and turbochagers can only compress gas and air to a certain point where as mother nature becomes the compressor in the jet.
Hence, at the transition from the dive to the climb, in a piston driven plane, the power consumption would/could be at or beyond it's highest level, and would neggate some of your explination.
I guess the manuver would therefore be highly dependant on the speed at which it is begun.
I would enjoy hearing your thoughts on this, and if you can get some real AC data, I think we would all rest much easier.
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Sky Viper