Aces High Bulletin Board
Help and Support Forums => Help and Training => Topic started by: Lephturn on February 03, 2001, 11:46:00 AM
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A great thread... sorta buried in the General forum.
http://bbs.hitechcreations.com/smf/Smileys/default/Forum1/HTML/007806.html (http://bbs.hitechcreations.com/smf/Smileys/default/Forum1/HTML/007806.html)
Read it all guys... it's a great thread.
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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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and here is a simple picture ( i hope helpfull picture )
(http://www.raf303.org/filip/funny/chase1-SHQ.jpg)
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That is a good description of using a dive to get into guns rang... however it is not the topic of the thread above. (Well, the good part anyway. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif))
While the above works while just short of guns range, the maximum E gaining speed discussed in the thread will help you close from much farther out.
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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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yup (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
but i decided to post it here 'cuz topic is let's say "similar" (more or less) and it can be helpfull for a newbies.
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or BadBoys new article:
http://www.simhq.com/simhq3/sims/air_combat/energymgmt/ (http://www.simhq.com/simhq3/sims/air_combat/energymgmt/)
-Westy
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Originally posted by Lephturn:
A great thread... sorta buried in the General forum.
http://bbs.hitechcreations.com/smf/Smileys/default/Forum1/HTML/007806.html (http://bbs.hitechcreations.com/smf/Smileys/default/Forum1/HTML/007806.html)
Read it all guys... it's a great thread.
Read it VERY critically. Think carefully about the theory being expounded. If you do you will realize how wrong that theory is.
Dwarf
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Please explain.
I've discussed this in the thread mentioned, and it makes sense to me.
If there is something I'm missing, please point it out. I'm more than willing to admit I'm wrong if I've made an error. Do you deny that this tactic works, or that it should work? Is there some assumption here we've made in error? Even re-reading it I don't see the problem at this point.
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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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To be sure we're not referring to different articles again... and I do apologize for my mistake in thinking the 2 URLs referred to a single article... I'm talking strictly about http://bbs.hitechcreations.com/smf/Smileys/default/Forum1/HTML/007806.html (http://bbs.hitechcreations.com/smf/Smileys/default/Forum1/HTML/007806.html) and the linked article referenced within that thread.
See my post near the end of that thread for a fuller explanation. The short version is that you cannot sacrifice altitude in a prop plane without also losing Energy. And, unless you can somehow GAIN energy you cannot overtake the lead aircraft in the scenario Nuku started with.
Badboy's other article, covering EM diagrams and how you use them to properly employ your aircraft, is both correct and very well presented.
Dwarf
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Originally posted by Dwarf:
The short version is that you cannot sacrifice altitude in a prop plane without also losing Energy.
It is infact the quickest way to gain energy, unless of course you are already at your maximum speed and critical altitude.
And, unless you can somehow GAIN energy you cannot overtake the lead aircraft in the scenario Nuku started with.
I agree.
Badboy
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Dwarf
Can you fill out your profile a bit more, please? I don't mind strong opinions, but it helps to know a little more about where they are coming from.
Andy
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All you gain by diving is speed, and there's more to Energy than merely speed.
The physics of propellor driven flight are such that you can never gain enough speed in a dive to make up for the Energy you lose in altitude. Drag and propellor dynamics see to that.
Careful Energy management can minimize the loss you incur in the dive, but unless you can accelerate to a greater speed at your current altitude, or climb to a higher altitude and accelerate to the same or greater speed there, you won't have increased your Energy state.
Dwarf
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Andy -
No Thanks.
I don't ask anyone to accept anything I say without verifying it first.
This isn't about opinion, or who has the better reputation or credentials, but about which are the relevant facts.
Never accept any theory without verifying it for yourself, no matter how reliable the source. Everyone makes mistakes.
Dwarf
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Dwarf
You appear to know something about this subject...and I admit, I don't.
With regard to this statement..."Careful Energy management can minimize the loss you incur in the dive"...what techniques do you recommend to accomplish this?
You said, "The physics of propellor driven flight are such that you can never gain enough speed in a dive to make up for the Energy you lose in altitude. Drag and propellor dynamics see to that". Would you explain this please.
I just noticed your last post. You are right...this is not about anyone being 'better' at anything...but you plainly stated that another person was wrong in what he wrote. OK. That may or may not be. The burden is on you to demonstrate why. As it stands now, you are only willing to tell us to go figure it out for ourselves.
That's not very forthcoming on your part. An explanation or a reference would be better, as would be a more complete profile that would allow the rest of us to make our own judgement about the validity of your posts.
Andy
[This message has been edited by Andy Bush (edited 02-07-2001).]
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Originally posted by Dwarf:
All you gain by diving is speed,
You made the same point in another thread and I disagree.
But firstly, the method doesn't depend on gaining energy during the dive, no one said it did. The main reason for diving is to get you to the speed where you do gain energy at the fastest rate, as quickly as possible. The speed for best energy transfer. You could accelerate to it in level flight, it would just take longer.
Now, regarding energy gain in the dive, you will gain energy in a dive whenever you do it with positive Ps, just as you would at any other attitude. However, if you do the dive at 0g you will gain more energy than you would if you had stayed level because your induced drag would be much lower. The speed for maximum energy transfer is below top speed and so you will still have positive Ps and still be gaining energy when you pullout.
In the other thread you said:
First you have to burn some E converting from straight flight to the dive
I disagree. If you push gently to zero g you will see an immediate reduction in drag.
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
Not so, drag is less at zero g than it is in level flight, speed for speed.
the difference in Drag between velocities of 500 fps and 525 fps is 25625 x Coefficient of Drag).
Since Cdo would be about the same at both those speeds you are saying that an increase in speed of 25fps would result in 25625 times more drag. Infact the drag would only increase by a small percentage of its original value.
Badboy
[This message has been edited by Badboy (edited 02-07-2001).]
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Originally posted by Andy Bush:
With regard to this statement..."Careful Energy management can minimize the loss you incur in the dive"...what techniques do you recommend to accomplish this?
Use a gentle push to 0G to initiate the dive. Be smooth in all stick movements. Use the absolute minimum G necessary to make corrections or initiate any maneuver. Stay coordinated and as close to neutral trim force as you can. Just basic E conservation stuff.
You said, "The physics of propellor driven flight are such that you can never gain enough speed in a dive to make up for the Energy you lose in altitude. Drag and propellor dynamics see to that". Would you explain this please.
I won't bore you with the math (it's really arcane and tedious). If you want to check it for yourself, see:
Theory of Flight by Richard von Mises,
Chapter V starts his discussion on Drag
Chapter XI is where he starts talking about propellors
and Chapter XIV is where he discusses performance
or
Theoretical Aerodynamics by L.M Milne-Thompson
He takes things up differently, and you'll be all over his book.
Dwarf
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You can potentially use a dive to gain Energy if you terminate the dive at a speed that still permits positive Ps and you don't dive too low. Start the dive from too high a speed or terminate the dive at too high a speed and you lose Energy every time in a prop plane. Dive too far and you won't be able to regain current altitude at current speed either.
A zero G pushover results in an immediate (and transitory) reduction in Drag, which leads to an immediate (and growing) increase in speed which causes an immediate (and exponentially growing) increase in Drag, which leads to a need to initiate a pullout at some point. That loads up the airframe even further, bleeding off some of the speed you dove to attain. Drag is now having a big ole lunch on your E. At some point, you need to initiate the climb... which once again loads up the airframe and bleeds off speed/momentum that you need to carry you back to where you started.
IF you started from a low enough speed and terminated the dive while you still had a Ps credit, and were very, very careful about the loads you applied at every stage, AND IF you accidentally hit your magical maximum energy transfer speed going back up, you might possibly make it back to where you started with some kind of Energy credit. Not likely, but possible.
Drag is certainly less at a given speed at zero G than any other loading. See above for why that really doesn't matter much.
What I said was that the difference in the squares of 525 and 500 is 25625. That is the additional amount that gets multiplied by the Coefficient of Drag to help give you your new total Drag. Drag may only increase by a small percentage as a result but that percentage is certainly greater than the percentage increase in speed, and speed is only a small percentage higher also. Further, Ps is reduced at best and falls to zero or below at worst as a result.
All of which adds up to this being a very long-shot tactic in practice, even when the conditions are perfect and you hold your mouth just right.
It would be far better Energy Management to preserve or increase your existing altitude and go looking for a different target.
Dwarf
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Originally posted by Dwarf:
I won't bore you with the math (it's really arcane and tedious). If you want to check it for yourself, see: Theory of Flight by Richard von Mises,
Dwarf
Judging by the absurd drag calculations you posted earlier, you would be better advised to read it again yourself.
Badboy
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Dwarf
First you claim that you can't gain energy in a dive... Now you say:
You can potentially use a dive to gain Energy
You are contradicting yourself!
if you terminate the dive at a speed that still permits positive Ps and you don't dive too low. Start the dive from too high a speed or terminate the dive at too high a speed and you lose Energy every time in a prop plane.
What you are saying then, is that if you do it the way I said, it works?
IF you started from a low enough speed and terminated the dive while you still had a Ps credit, and were very, very careful about the loads you applied at every stage, AND IF you accidentally hit your magical maximum energy transfer speed going back up, you might possibly make it back to where you started with some kind of Energy credit. Not likely, but possible.
You are correct, it is possible. That's the point I've been making all along.
What I said was that the difference in the squares of 525 and 500 is 25625.
No, what you said was...
(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)
Which is very different. I don't think anyone who actually knew what they were talking about could make a mistake like that... do you?
Drag may only increase by a small percentage as a result but that percentage is certainly greater than the percentage increase in speed, and speed is only a small percentage higher also.
Ohh boy... Now you are really talking nonsense!
All of which adds up to this being a very long-shot tactic in practice, even when the conditions are perfect and you hold your mouth just right.
You started by saying it wouldn't work, even calling it fantasy, now you say it is a long shot... Contradicting yourself again!
It would be far better Energy Management to preserve or increase your existing altitude and go looking for a different target.
Then do that, that will certainly work too, but meanwhile the guys taking my advice will be getting the kills you let get away. Not to mention, that they won't be getting killed as easy as your buddy Nuku (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Badboy
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Originally posted by Badboy:
Judging by the absurd drag calculations you posted earlier, you would be better advised to read it again yourself.
Badboy
OK, you don't want to take the easy way out.
Total Drag is the sum of all the component drags the entire aircraft experiences. The parasitic drag formula for each component is:
Dp = Cp x(air density/2) x Velocity squared x Area
Dp = parasitic drag for that component
Cp = Coeficient of drag for that component
For any given altitude all terms on the right hand side of the equation can be reduced to a constant except for Velocity.
Because the density of air is such a tiny number (0.001267 slugs per cubic foot at 20k in a standard atmosphere), this constant is always considerably less than 1.0.
Every part of the aircraft is going to experience parasitic drag no matter what G loading you impose. The magnitude of that parasitic drag is directly the result of the Velocity you are operating at, squared.
If you operate at a Velocity of 500 fps, you multiply that constant by 250,000.
If you operate at a velocity of 525 fps, you multiply that constant by 275,625.
The difference in those two numbers is 25625. And, that is the difference in the magnitude of the Drag the aircraft experiences between those two speeds at a loading of zero G.
Dwarf
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Let's back up a minute.
Nuku presented you with a situation that you've already conceded (in another thread) is impossible. YOU took that to mean he didn't know what he was talking about and propounded a theory to explain how it might be possible.
The simple fact is, that for the conditions he set forth, and as you have already conceded, your theory doesn't work. (Except maybe in some simulations whose physics modeling no one seems willing to question. [EDIT]Possibly making this the next chapter in "How To Game The Game", right along with AW's spin turns and WB's warp rolls.[/EDIT])
In all practical situations involving prop aircraft it doesn't work. (regardless of the speeds employed).
I'm simply willing to allow that... theoretically... it might work under certain VERY special circumstances. Circumstances far different from the ones Nuku set out.
Dwarf
[EDIT] It is a viable jet tactic though.
Also keep in mind, as was also pointed out in the other thread, that props don't exhibit the molar shaped plot you're basing this theory on.
[This message has been edited by Dwarf (edited 02-07-2001).]
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Originally posted by Badboy:
Dwarf
Then do that, that will certainly work too, but meanwhile the guys taking my advice will be getting the kills you let get away.
Badboy
hmmmmm... guess you've never heard of Drag-n-Bag.
Dwarf
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Ok, the parts you copied from a book looks alright... Then you said:
Originally posted by Dwarf:
The difference in those two numbers is 25625. And, that is the difference in the magnitude of the Drag the aircraft experiences between those two speeds at a loading of zero G.
Dwarf
You are saying that the difference in the magnitude of the drag on the aircraft between those speeds is 25625... When a difference in speed of 25ft/s would probably only result in a difference somewhere inbetween one and two hundred pounds of drag. The figure you are suggesting is absurd.
Badboy
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Just something to think about:
We certainly have a simplified model in a simulation like Aces High, as compared to the real thing in any case. There is no way it could model EVERY possible nuance and change. Isn't it possible that something like this that would rarely work under special circumstances in real life might just work most of the time if done right in a computer game?
Dwarf, what I can tell you is that it seems to work in Aces High and Warbirds. Badboy has come up with a plausible explanation for why it works. Now maybe in real life the added complexities of flight might make it almost impossible to capatalize on this type of thing, but in the sterile, simplified environment we deal with, it works just fine.
I think the simplified "world" we deal with may have something to do with the results. (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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Originally posted by Dwarf:
The simple fact is, that for the conditions he set forth, and as you have already conceded, your theory doesn't work. (Except maybe in some simulations whose physics modeling no one seems willing to question.
You are confused. I have only ever agreed that it doesn't work in one special situation. It's an exception.
I'm simply willing to allow that... theoretically... it might work under certain VERY special circumstances. Circumstances far different from the ones Nuku set out.
Again, the condition in which it doesn't work is the one Nuku set out, i.e. when both aircraft are at their maximum speed. That's a special case, and very rare. When the aircraft are above their maximum energy transfer speed, the technique still works, it just doesn't begin with a dive.
Dwarf, you seem to be making use of several common fallacies in your arguments that will no doubt fool many, particularly those who don’t appreciate the subtitles of the way in which you have been manipulating the thread. So just for those who haven’t seen those methods before, I’ll explain what you are doing. I don’t believe you are doing it deliberately, because you don’t seem to be that smart.
One of the most common fallacies in polemics is simply failing to accept the burden of proof or asserting a claim without presenting a reasoned argument to support it. That of course would leave most arguments a little hollow, but not if you follow it up, as you have done, with a few more fallacies. All of your messages have begun by making assumptions that no one has disagreed with. By doing that you are using a ploy known as the "Straw Man", a technique of directing your argument against a point that isn’t in dispute simply because it is easier to refute. Of course I agree that if both aircraft are already at their max speed, diving is not the right thing to do… it won’t work, and I believe I have clarified that twice in one thread or another, once before you arrived. Naturally you need to ignore that fact so that you can make repeated attacks on the same point, because like the straw man, it’s easy to knock down. Your arguments also contain several other fallacies. You make creative use of the "Non Sequitur", the false implication that one thing leads logically to another, or simply that because there is a situation in which it doesn’t work, the technique doesn’t work at all. So, in order to reinforce that fallacy you repeat the same point in one guise or another, namely that the technique doesn’t work under the conditions set out by Nuku, which is a nice combination of the "Straw Man" and "Circular Reasoning". All you have really done is to repeat the obvious several times. Arguing that your claims are true by repeating them in different words and in different threads doesn’t make your point more valid. Nothing you have said is any truer after the third repetition than it was the first time. You have rounded all that off quite nicely by performing inept computations and repeatedly contradicting yourself… An aircraft can’t gain energy in a dive, and then it can… The technique doesn’t work, and then it does. I don’t believe you really have a clue!
The simple fact is that it does work. Aerodynamic theory predicts that it works, and the flight models of almost every current WWII simulation are sophisticated enough for us to observe it in action. Deal with it!
Badboy
[This message has been edited by Badboy (edited 02-07-2001).]
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This whole thread is intriguing since I can't really understand how what Badboy says will work (though in no way am I claiming it won't).
My question is, in a pursuit such as has been described (not already at max speed) where does the extra E come that allows you to catch the aircraft? My understanding of aerodynamics is related more to physics than actual aerodynamics but what actually causes the increase in E that would allow closure on the lead aircraft? The 0 G pushover doesn't generate E, though it does aid in acceleration, thus producing more speed, an obvious component of closure. I understand what you are saying, but why does the total maneuver result in a net gain in E (since you would have to both accelerate and climb back to you previous altitude to effect the intercept).
The path that the pursuing aircraft must fly is longer than the flat path, the acceleration component could be greater with 0'G, but the resultant speeds would lead me to believe that the drag over the leg of the flight the pursuer flies would be higher than the fleeing aircraft. The only way I could see a gain would be in something like prop efficency if the pursuit aircraft accelerated better in a higher speed range than the lead aircraft.
Maybe Dwarf and/or Badboy can clear this up for me... like I said, I'm not saying anyone is wrong, but I'm trying to figure out in my mind why this would work. Everything I know about physics says it shouldn't in a prop plane.
-Soda
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Leph -
I agree totally.
This is a simplified situation and not all "real world" effects can, or should be expected to carry over.
I believe this is one.
Is it worth doing the series of integrations necessary to prove it? Nah.
The only thing I'd really like to caution people about is that what Badboy outlines is really a jet tactic. Jet engines are marvelous things in many ways and permit some maneuvers that just don't work with a prop plane. Props make routine a couple of things that are highly dangerous in jets as well, so overall it balances out.
While I firmly believe he booted it in this instance, I'd like to repeat what I've said elsewhere about his article on EM diagrams.
Excellent work. Something everyone should read at least twice.
Dwarf
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Originally posted by Badboy:
Ok, the parts you copied from a book looks alright... Then you said:
You are saying that the difference in the magnitude of the drag on the aircraft between those speeds is 25625... When a difference in speed of 25ft/s would probably only result in a difference somewhere inbetween one and two hundred pounds of drag. The figure you are suggesting is absurd.
Badboy
I'm not suggesting anything. I'm merely pointing out to you the actual numbers that really apply to the situation you propose.
Dwarf
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Dwarf
>>Props make routine a couple of things that are highly dangerous in jets as well, so overall it balances out.<<
And what might these be? In the context of air combat maneuvers, that is.
Andy
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Originally posted by Badboy:
Again, the condition in which it doesn't work is the one Nuku set out, i.e. when both aircraft are at their maximum speed.
Ok, Lets backup again. Nuku started that thread by asking how "when both aircraft are at their maximum speed", the pursuing aircraft was able to catch him utilizing a series of dives.
How was your asserion that under other circumstances you believed it was possible, in any way responsive to his question?
Talk about straw men and manipulating a thread. The conditions, and your theory that exploits those conditions pertain both to a different type of aircraft, and a different situation than he was asking about.
He was asking why a particular apple was rotten. You started telling him about oranges. Why use his legitimate question to confuse the issue by introducing a whole different set of circumstances?
Simple. You had a theory you wanted to expound and you'd written an article about that theory you wanted to flog. So you hijacked the entire thread, and confused everyone who had identical concerns simply to tease them into reading your latest essay.
An interesting exercise in situational ethics.
The simple fact is that it does work. Aerodynamic theory predicts that it works, and the flight models of almost every current WWII simulation are sophisticated enough for us to observe it in action. Deal with it!
Badboy
I don't know about anybody else, but it's self eveident to me, that if two aircraft are accellerating from a speed well below their max, one aircraft can do so faster than the other by diving and then using that speed and geometry to shoot down the other aircraft. I think most of us can get that without fancy charts or an article, or hijacking Nuku's thread to inflate your ego.
Starting your own thread about how to make a minimum time, maximum energy climb would have been the logical and ethical thing to do. Just as disproving my numbers would be the logical thing to do. But, they say when you can't argue the facts you argue the law, and, when you can't argue the law, you destroy the character of the witness.
If it works, do it is a philosopy that seems to fit you. Have fun with it.
Dwarf
[This message has been edited by Dwarf (edited 02-08-2001).]
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Originally posted by Andy Bush:
Dwarf
>>Props make routine a couple of things that are highly dangerous in jets as well, so overall it balances out.<<
And what might these be? In the context of air combat maneuvers, that is.
Andy
Anything involving low speed flight or maneuvering. Props tolerate stalls and spins rather well. Such gyrations tend to make the clean air converter in jets stop working.
Dwarf
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Soda,
The way I understand it is thus:
The extra E to get to max speed (say 375) from a slower speed (say 200 Mph) comes from the engine. The question is, does the propellor/airframe combination convert that extra power from the engine into energy better at a higher speed? If the answer is yes, then a 0G dive to that magical "most efficient" speed, and a subsequent gentle zoom to maintain that speed, would convert that extra engine power into energy at a faster rate than flying at a speed below the magic number.
The only question to be answered is whether a higher speed can more efficiently convert engine power to energy, and whether it's enough to compensate for the E you may lose in the pull-up into zoom. Badboy will get time to do some tests and charts at some point, and then he we'll know for sure. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Lephturn - Aces High Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
Check out Lephturn's Aerodrome! (http://users.andara.com/~sconrad/)
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Soda -
My take on it is essentially the same as Lephturn's.
There should be two basic choices. Best prop efficiency speed and best airframe efficiency speed.
The overall solution will probably be the best compromise between those two speeds. But, it's also possible that absolutely maximizing power transfer or absolutely minimizing drag proves to be the vital component. Ideally, for a few aircraft at least, the two basic speeds will be close enough together that there isn't much to choose between them.
Practically speaking, most folks will just dive until they feel they have enough speed, level until the angle back to the bad guy looks right, ease back up to him, and start ripping his belly open once they get to decent guns range.
Dwarf
[This message has been edited by Dwarf (edited 02-08-2001).]
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Originally posted by Dwarf:
I'm not suggesting anything. I'm merely pointing out to you the actual numbers that really apply to the situation you propose.
Dwarf
You merely pointed out that an increase in speed of about 25ft/s would cause drag to increase by a magnitude of 25625, when in fact it only increases by a little more than 100lbs. That's about 200 times smaller than your figure. An increase in drag of the magnitude you stated is nonsense.
Badboy
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I've really got to stop responding to this nonsense.
Exactly what part of component drag don't you understand? Exactly what part of Coefficient of Drag don't you understand? Exactly what part of V^2 don't you understand?
Dwarf
{For those who haven't yet walked away in utter frustration]
To reiterate the bone of contention here:
We've already agreed that for the stated case of 2 aircraft both at max speed, diving accomplishes nothing.
We've already agreed that when both aircraft are still accelerating, one can do so faster by diving than the other can by remaining level.
We've even agreed that when the diving aircraft gains enough of a speed advantage he can ease back up to the fleer and rip his guts out.
What's still at issue is whether it's possible for a prop aircraft to enter an evolution where he descends from an altitude and then returns to it having gained Energy in the process. I say no. He says yes.
[EDIT] More correctly stated... that he can return to that altitude having gained more energy than if he had continued accelerating in a straight line, although I'll stand by my no the other way, too. {/EDIT]
He claims to have data supporting his allegation. We haven't seen it yet.
[This message has been edited by Dwarf (edited 02-08-2001).]
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Lept/Dwarf,
I was thinking along the same lines as you both, basically, you are finding what would be considered a "sweet spot" where you thrust is maximized (engine most efficiently converting hp to thurst through the prop) while also entering a spot where the airframe is performing at a percentage less drag (compared to thrust). A good mid-high speed accelerator (say from 275-350 )would therefore have an advantage getting to that mid speed as soon as possible and using that higher speed acceleration to catch a plane that has a more linear (or exponential) drag increase.
The shallow dive makes total sense, unloading the aircraft, finding the "sweet spot" also is understandable. On the flip side, drag, the enemy of this procedure, increases with speed, as well as the fact that all the maneuvers (save the initial 0 G pushover) occur at higher speeds and thus the drag penalty should be higher. It would take one mighty soft hand on the stick to not completely bleed away all the possible advantage you could get by simply pulling 1G of extra pull-up at the last climb of the chase.
Interesting concept, though I suspect it is VERY dependant on aircraft involved. I'd still love to see some results of testing Badboy, if you can get around to it. It sounds like a mighty fine line of performance to walk, but sometimes that's all it takes to bag a kill.
Thanks for your response,
-Soda
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Yep, this will necessarily be aircraft dependent. I suspect if it works out anywhere, it's going to work out in the P-51 and the Jug.
I'm hoping on the Jug. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Lephturn - Aces High Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
Check out Lephturn's Aerodrome! (http://users.andara.com/~sconrad/)
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Ok, Lets backup again. Nuku started that thread by asking how "when both aircraft are at their maximum speed", the pursuing aircraft was able to catch him utilizing a series of dives.
How was your asserion that under other circumstances you believed it was possible, in any way responsive to his question?
Because the guy chasing him had managed to catch him. Had they both been at maximum speed that shouldn't have happened, the most likely alternative was that the original assumption of maximum speed was at fault.
He was asking why a particular apple was rotten. You started telling him about oranges. Why use his legitimate question to confuse the issue by introducing a whole different set of circumstances?
The original question was circular. "If an aircraft is at its top speed, how can it go any faster?" It can't, the conclusion is a point stated in the premise. If the aircraft actually did go faster, the aircraft could not have originally been at its top speed. I genuinely believed that must have been the case. No other situation would have explained the outcome. Nuku wanted to know how it could have happened and I did my best to explain it.
Simple. You had a theory you wanted to expound and you'd written an article about that theory you wanted to flog.
I'm not sure what you mean by flog? If you mean to sell for money, that's not true. Everything I've done or written about Aces High as been 100% free and gratis. Those articles were born of a desire to help others, no reward, other than perhaps a little kudos has ever been anticipated. However in this case, I must say I regret ever posting it. You may enjoy these endless diatribes, I do not.
I don't know about anybody else, but it's self eveident to me, that if two aircraft are accellerating from a speed well below their max, one aircraft can do so faster than the other by diving and then using that speed and geometry to shoot down the other aircraft.
You are now agreeing the procedure is correct! That's amazing, you have been arguing all this time that it won't work, and here you state that it is self evident.
I think most of us can get that without fancy charts or an article, or hijacking Nuku's thread to inflate your ego.
Actually I was trying to be helpful. I have always believed that you only get out of life as much as you put in. When I enjoy something I'm doing I believe in giving something back. That's what I thought I was doing... Now I'm not so sure it was the right thing. Try to help, and look what happens. I have a feeling my first two Aces High articles may be my last.
Badboy
[This message has been edited by Badboy (edited 02-08-2001).]
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To help everyone understand the process at immediate issue here -
D = (Cd(density/2)Area)V^2
Let's take one density - say 8,000 feet = 0.001869 in a standard atmosphere.
Let's take one aircraft component - a wing.
Let's assign our wing an area of 250 sq ft.
Let's assign our wing a Coefficient of Drag = 0.0006.
Now the first part of the Drag Equation looks like this:
0.0006(0.001869/2)250 = 0.000140175
This becomes the constant to use to test against Velocity.
Using the already stated V of 500 fps and 525 fps:
First Result: 0.000140175 x 250000 = 35.04375
Second Result: 0.000140175 x 275625 = 38.63573438
38.6 - 35 = 3.6
3.6/0.00014 = 25714
which is the difference in magnitude of the two results based on our constant.
Remarkably close to 25625 for rounding off the results.
Dwarf
[EDIT] NOTE; I used the bare square footage of the wing to keep things simple.
An actual wing would have a wetted area 2+ times the planform area.
Exactly how big the + would be is dependent on the exact profile of the wing.
[This message has been edited by Dwarf (edited 02-08-2001).]
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Dwarf
You have displayed some mighty fine book learnin'.
With regard to your statement about jets and their response to 'stalls and spins', this knowledge comes better from hands on experience rather than reading some aero text.
So, how much actual jet fighter time do you have? Got any experience in high AOA behavior? Ever rode thru a departure (BTW, that's what we call a 'spin' entry these days)? What exactly happens when you stall a fighter when pulling G?
Anyone can argue theory. How much practical experience do you have?
Andy
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Because the guy chasing him had managed to catch him. Had they both been at maximum speed that shouldn't have happened, the most likely alternative was that the original assumption of maximum speed was at fault.
OK. I am more suspicious of sim flight models than you are. My impression was that given the stated situation, the stated result came from a flaw in the program.
The original question was circular. "If an aircraft is at its top speed, how can it go any faster?" It can't, the conclusion is a point stated in the premise. If the aircraft actually did go faster, the aircraft could not have originally been at its top speed. I genuinely believed that must have been the case. No other situation would have explained the outcome. Nuku wanted to know how it could have happened and I did my best to explain it.
Guess I trust people more and programs less than you do.
I'm not sure what you mean by flog? If you mean to sell for money, that's not true. Everything I've done or written about Aces High as been 100% free and gratis. Those articles were born of a desire to help others, no reward, other than perhaps a little kudos has ever been anticipated. However in this case, I must say I regret ever posting it. You may enjoy these endless diatribes, I do not.
Sorry you see it that way.
You are now agreeing the procedure is correct! That's amazing, you have been arguing all this time that it won't work, and here you state that it is self evident.
No, I disagree with your assertion that there is some magical evolution that will allow you (while in pursuit) to descend from an altitude and then return to that altitude having gained Energy.
Gaining speed faster diving than another plane can by remaining level was never the issue. Energy gain was (and is) the issue.
Actually I was trying to be helpful. I have always believed that you only get out of life as much as you put in. When I enjoy something I'm doing I believe in giving something back. That's what I thought I was doing... Now I'm not so sure it was the right thing. Try to help, and look what happens. I have a feeling my first two Aces High articles may be my last.
Badboy
I think that's true. Based on your other article, you have very valuable insights to offer.
I hope you don't let the fact that your enthusiasm got the best of you and I thwacked you upside the head for it, diminish that.
Dwarf
[EDIT] Now, compile your data and prove me wrong if you can. I'll be more than happy to congratulate you if you do.
[This message has been edited by Dwarf (edited 02-08-2001).]
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Andy -
Nice mousetrap, but I already said I'm not going there. You're more than welcome to be stud duck.
As far as what happens at departure, that depends on the plane. No two models behave identically.
Given your credentials, maybe you care to share what happened to the Tu-144 at the Paris airshow some years ago, when it was forced to avoid a photo-recon Mirage.
Dwarf
[This message has been edited by Dwarf (edited 02-08-2001).]
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Originally posted by Dwarf:
First Result: 0.000140175 x 250000 = 35.04375
Second Result: 0.000140175 x 275625 = 38.63573438
38.6 - 35 = 3.6
3.6/0.00014 = 25714
which is the difference in magnitude of the two results based on our constant.
Nope, according to those calculations the difference in the magnitude of the drag would be 3.6 that's all.
25625 is only the difference in the square of the airspeeds, and you never had to go to such lengths to get it, it is just 525^2 less the 500^2. You previously stated the difference in the magnitude of the drag was 25625, as you have again here, and that of course is utter nonsense.
However, if you take 25625, you can use it to find the true difference in the magnitude of the drag, like this 25625*0.00014 = 3.6 as before. Perhaps that's what you meant, if so it certainly is not what you said, and many of your previous misguided statements were based on it... So what part of that didn't you understand?
Badboy
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Dwarf
I'm not interested in being the ' stud duck' or anything else. I am interested in knowing where your expertise comes from.
>>Given your credentials, maybe you care to share what happened to the Tu-144 at the Paris airshow some years ago, when it was forced to avoid a photo-recon Mirage.<<
Heck if I know. I wasn't there. Those that were are dead. The presumption as far as I know is that the Tu pilot broke up the jet in trying to avoid a mid-air.
What does that have to do with this thread?
Let's try something simple. Assume you are flying a F-4 (hard wing) and a F-104 at 300KIAS in level flight. You aggressively pull the stick full aft with no aileron input. What happens in each case?
One other. You are in a hard turn at 300KIAS in each airplane. You aggressively apply opposite aileron while maintaining your G in order to reverse your turn. What happens?
Try to be specific...I imagine the folks here would like to know how these jets handle.
Andy
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Badboy, I hope you don't let this discourage you from writing articles!
I know there are a lot of us that appreciate your work. Whether your theory is proven to work or not is largely irrelevant in my opinion. I think many have learned a great deal from it, regardless of the outcome. I know I certainly have. Most of those folks are not going to even see this thread, let alone venture to step into the middle of this discussion.
I hope this thread will die now. It's quite clear you two have different positions, and I think you've both made it plenty clear what those are. Nothing is getting settled by continued discussion. The only way to prove or disprove this theory will be to test it. I think Badboy will likely do that at some point, and we'll reap the great benefit of his hard-earned data regardless. I find it sad that he is the only one who has promised to actually do some testing and post the results at some point. Think how much information could have been gathered in the time spent arguing on the board. Sigh.
At the very worst case, Badboy's theory will prove to be wrong in the long term, and we'll have learned something about E and prop fighters. In the best case we will all have gained new insight and information we can use to be better virtual pilots. The bottom line here is that there is nothing at stake except pressing the Fly button again. There is no need to keep beating this horse, it died about 10 posts ago. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Lephturn - Aces High Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
Check out Lephturn's Aerodrome! (http://users.andara.com/~sconrad/)
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Originally posted by Lephturn:
At the very worst case, Badboy's theory will prove to be wrong in the long term, and we'll have learned something about E and prop fighters.
I don't agree that is the worst case, please allow me to explian... The issue seems to be, can the attacker gain energy more quickly than the defender? The answer is yes… by using best energy transfer. That begs the question, why does it work? That seems to be where folk get stuck... Ok, let’s review the facts.
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 I hope to resolve 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. The worst case scenario is that we may find that some aircraft are not able to take advantage of it.
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.
Another issue I want to consider when I have the Vt speeds at hand, is how the above procedure for optimising energy transfer should be tempered by the alternative strategy of optimising closure, which would involve abandoning Vt near the critical altitude to achieve maximum true airspeed. That raises another new issue… Personally, given the choice of having my Es as altitude or Speed, I tend to prefer speed, but it is a delicate balance and can be subjective because many pilots prefer to always be higher with correspondingly higher total energy, but that can be a problem in the above situation because the defender loses a lot of energy when forced into their break turn. My personal preference would be not to follow a best energy transfer solution to its conclusion. So it should make an interesting, perhaps contentious article.
In the best case we will all have gained new insight and information we can use to be better virtual pilots. The bottom line here is that there is nothing at stake except pressing the Fly button again. There is no need to keep beating this horse, it died about 10 posts ago. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Amen to that!!
Badboy
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Badz andy and dwarf nice thread!
What fine minds you all have (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Now what names do you all fly under?
Why cant i find you under the score page?
EYE
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Badboy wrote:
"Try to help, and look what happens. I have a feeling my first two Aces High articles may be my last."
I don't believe it.
Firstly, because he knows full well that his work has helped far too many people to be left undone.
Secondly, if we couldn't shut him up in Airwarrior, I doubt that you silence him here :-)
The whole argument has become much too rareified.
I gather the impression that a (superficialy) simple question was being asked by some one who wanted simple guidelines on how best to fly in the arena. Much of the effort spent here would require far too much "head down" time to be of use for the majority of us.
Both proponants seem to be saying the same thing, albeit in a perhaps over academic way.
There still remains an important point:
What do I, as a total dweeb actualy do with stick in hand to use this newfound knowledge? There's no "sweetspot" graduation on the airspeed gauge.....
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Originally posted by Seeker:
There still remains an important point:
What do I, as a total dweeb actualy do with stick in hand to use this newfound knowledge? There's no "sweetspot" graduation on the airspeed gauge.....
There really isn't anything you can do with it. I've spent a fair amount of time testing to try to find the high speed sweet spot in the P-51D and was unsuccessful. I suspect that the already known max ROC speed for each aircraft is as good as it gets.
Dwarf
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What's not known, at least by me, is what speed the best climb-rate can be attained at for my plane.
I'd love to know what the best climb-speed curve looks like from SL to say 30k in the Jug. I would think that speed would go up, the higher you get... correct?
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Lephturn - Aces High Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
Check out Lephturn's Aerodrome! (http://users.andara.com/~sconrad/)
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Originally posted by Lephturn:
What's not known, at least by me, is what speed the best climb-rate can be attained at for my plane.
I'd love to know what the best climb-speed curve looks like from SL to say 30k in the Jug. I would think that speed would go up, the higher you get... correct?
I think you'd have to acquire a pilot's manual for the P-47 and then fly according to the climb regime outlined there to know for sure what speed and rate you'd realize at any given altitude. Manifold pressure reductions along the way are probably mandated.
As I understand things, indicated airspeed should decay with alt (for constant power operation).
Dwarf
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Originally posted by Lephturn:
What's not known, at least by me, is what speed the best climb-rate can be attained at for my plane.
I'd love to know what the best climb-speed curve looks like from SL to say 30k in the Jug. I would think that speed would go up, the higher you get... correct?
Actually, I have always produced diagrams like this one:
(http://www.netcomuk.co.uk/~badboy/PDF/BClimb0k.jpg)
They are automatically produced at the same time as the EM diagrams, they show the speed for best climb rate and top speed. Normally a complete analysis for an aircraft would include a set of EM diagrams for various weights and altitudes, along with the Pa Pr diagrams. However, because of the bandwidth required for these diagrams and the relatively small amount of info, I don't normally bother to use them, I just put the info into a data plate.
Anyway, when you have a set of those, you get the variation of climb rate and best climb speed with altitude.
Hope that helps...
Badboy