Energy Maneuverability Diagrams

[Badboy]

Originally posted by HoHun
Well, not really. The interesting thing about specific excess power is that it's highly dependend on the flight condition. By your diagram, a Fw 190 would appear to be greatly inferior to a Spitfire V throughout the envelope (with the exception of its greater top speed). In reality, it has a considerable power advantage at 1 G at all speeds, and is no worse than the Spitfire at high speeds and moderate Gs either.

EM diagrams do provide all of that information when the full range of Ps curves are included. Even when they aren’t, the same conclusions can be reached if you use an alternative source for 1g climb rate. Let me explain. The EM diagrams I have been posting look like the diagram below, which is an overlay of the Spit v 190 comparison you have used.



This second diagram shows how it would look if I included incremental Ps curves, but just for the positive Ps so that the ability of each aircraft to climb while turning can be seen. If you compare the lowest set of positive Ps curves for each aircraft you notice that the 190 has a clear Ps advantage at very low turn rates, and thus at g values close to 1g. That positive Ps advantage means it can out climb the Spitfire at low G, and at a higher speed, which means it can gain altitude and separation at the same time, which of course leads to your conclusion.



However, even using the first diagram, and acknowledging the fact that it doesn’t contain the same amount of information, I think the same conclusion could be reached with knowledge of the aircraft’s climb rates, and those curves are already published on the HTC website. Indeed, An aircraft with a better climb rate at a higher speed, is always going to have that same option, providing it has the separation to use it safely. So the conclusion you made will be generally true in that case and you don’t need an EM diagram to tell you that, which is why the same conclusion was so quickly and easily reached by the Luftwaffe pilots who employed such tactics in the 40s.  

The EM diagrams I produce, could easily provide that information, but they are primarily intended for the guys who want to know what happens when they use significantly more than 1g. So I think I’m fairly comfortable omitting the additional Ps curves for the improvement in clarity, since readers are still able to reach the proper conclusion and make the correct tactical decisions.

Badboy

[F4UDOA]

BadBoy,

Question, I thought the line represented intentanious G's. I have done testing I AH where I can pull 3G's well under 200MPH.

Is this sustained or intentanious turns?

[Badboy]

Originally posted by F4UDOA
BadBoy,

Is this sustained or intentanious turns?

Both. EM diagrams, give the instantaneous, and sustained turn rates, and depending on how far from the Zero Ps curve the instantaneous turn rate is, an indication of how an aircraft will sustain, gain or lose speed or altitude and thus energy.

On the diagrams I produce for AH, when two aircraft are overlaid, you can see both the instantaneous and sustained turn rates for each aircraft, and you can also see which aircraft will gain or lose energy more quickly during a turn at each point in the envelope. That's a lot of very valuable information.

If I included the additional Ps curves, and labelled them up, you could tell exactly what the instantaneous and sustained ability was, and make statements such as... At this point in the envelope Aircraft x has an instantaneous turn rate of xx but to sustain it, will need to lose altitude at xx ft every second, or lose speed at xx ft/sec every second. So, for every point in the envelope, you know exactly how an aircraft will turn, and if it can climb or needs to dive while doing so, and by how much. The way I draw the overlays, you can still see which aircraft has the best instantaneous ability, the best sustained ability, and you can see which aircraft will gain or lose energy more or less quickly, so if you know how to interpret it, you can still make the same good decisions.

Badboy

[HoHun]

Hi Badboy,

>The EM diagrams I produce, could easily provide that information, but they are primarily intended for the guys who want to know what happens when they use significantly more than 1g. So I think I’m fairly comfortable omitting the additional Ps curves for the improvement in clarity, since readers are still able to reach the proper conclusion and make the correct tactical decisions.

If my conclusions are self-evident because everyone knows that the Fw 190A outclimbs the Spitfire V, your conclusions are just as self-evident because everyone knows that the Spitfire V outturns the Fw 190A :-)

If you "use significantly more than 1g", you're going to lose your energy quickly, and if that's your focus of interest you're probably not using energy tactics anyway.

Your diagrams with the positive Ps graphs added makes an important step from a mere manoeuvrability diagram to a true energy manoeuvrability diagram, though I've got to admit you're right they're hard to read.

That's why I think a different way of graphing the energy information might improve the usefulness of such diagrams, and we should be looking for a different form to present the same information.

Regards,

Henning (HoHun)

[Virage]

each Ps line = how many feet per climb? (or dive if u showed the negative Ps lines)

I love the Energy fight.  Full EM charts are gold.  Thnx for this great info.

[Badboy]

Originally posted by HoHun
Hi Badboy,

If my conclusions are self-evident because everyone knows that the Fw 190A outclimbs the Spitfire V, your conclusions are just as self-evident because everyone knows that the Spitfire V outturns the Fw 190A :-)

Absoulutely, which is why I wouldn’t normally have bothered to overlay the diagrams for those two particular aircraft, it was your comparison not mine :-) There are many other comparisons that aren’t so obvious, and even I have been surprised and delighted by the results, particularly when other aircraft configurations including the use of bombs, gun pods and flaps etc, are compared.    

Your diagrams with the positive Ps graphs added makes an important step from a mere manoeuvrability diagram to a true energy manoeuvrability diagram, though I've got to admit you're right they're hard to read.

Yep, and I’ve had similar discussions with real fighter pilots who take the use of that type of diagram far more seriously than I do, including a weapons school instructor, and the conclusion seems to be that the form of diagram I am using now is an acceptable compromise for usefulness and simplicity

That's why I think a different way of graphing the energy information might improve the usefulness of such diagrams, and we should be looking for a different form to present the same information.

Yep, take a look at the alternative type of EM diagram shown below. With this sort of EM diagram, you don’t need a multitude of Ps curves because the angle of descent or climb can be read directly off the left hand vertical axis.



From that sort of diagram, you can read off the left vertical axis what angle of climb or descent can be achieved for any flight condition (in terms of the speed, load factor and turn radius), while the time for a 360° turn under those conditions can be read from the right hand axis. For example, for that diagram, if you entered a 6g turn at 200mph, you could turn 360° in under ten seconds with a turn radius of about 450ft, but to sustain it you would need an angle of descent of about 34° which I think is too steep to be a viable option.

That was the sort of EM diagram available during WWII, and I now produce both types automatically for every new aircraft I do, but I haven’t published any yet.

Badboy

[Badboy]

Originally posted by F1Bomber


Most importantly, I have to thank badboy for putting in all the work in the EM diagrams. It has really made my flying and also fun in the arena 10x better. to you badboy.

If you got the yak9U badboy, could you please post it, all diagrams that i have made, do tend to be 50% correct well testing.

Thanks F1Bomber, glad it was helpful.

I do have the EM diagrams for the Yak9U, and the La7 etc but I was planning to publish them in an article on the Russian front at SimHQ similar to this one I did for Il2 Forgotten Battles...

http://www.simhq.com/_air/air_065a.html

So I'll let you know as soon as it is ready.

Badboy

[F1Bomber]

NP Badboy, i have tried to make acouple of EM diagrams though some tools here and there. Have matched the data up against flying on aces high and i get mabe a 10% error rate with the real data to the calculated conclusion.

Though my inbox has been going wild with "YOU GOT MAIL" message scarying the crap out of me at 3 oclock in the morning here down under. But its been a intresting read these last couple of days on the bbs. Have learnt alot and still need to learn more about flight models ect.. ect..

Now that pizza map has turned its ugly head towards me, i have found other intrested instead of taking my yak up now and then. I normaly take up a long range P51 and do scouting missions at 30K behind enemy land and bomb there factories. Or i take a P47 and head up to 30K and kill all the spits and nikis, that somehow just dont turn good up at those alts.

P.S. Its werid, i have left aces high, about 20 times and still come back because the community here is 100% much better and more mature than other games i have tried.

Well is 5 oclock in the morning and i just got another email ( you got mail ) weeee, but thanks and a big Badboy. I cannot wait until you post those EM Diagrams, my family will never hear the end of it

[HoHun]

Hi Badboy,

>Absoulutely, which is why I wouldn’t normally have bothered to overlay the diagrams for those two particular aircraft, it was your comparison not mine :-)

I could say it was chosen to demonstrate that your diagram doesn't even show the self-evident ;-) But of course, with the extra Ps lines your diagram was quite sufficient to reach the conclusion I pointed out.

The reason for my choice simply was that I needed an example where I could be sure everyone would agree on the conclusions.

>That was the sort of EM diagram available during WWII

I was surprised to see they even had these diagrams, but of course, the concept of energy manoeuvrability was undiscovered yet.

>Yep, and I’ve had similar discussions with real fighter pilots who take the use of that type of diagram far more seriously than I do, including a weapons school instructor, and the conclusion seems to be that the form of diagram I am using now is an acceptable compromise for usefulness and simplicity

I'd guess the reason is that jet fighters' energy manoeuvrability diagrams vary much more than propeller fighters'. Part of this is related to the fact that for propeller fighters, best turn rate and smallest turn radius coincede, while these are two different parameters for jets.

I still believe there should be some better way of comparing (and understanding) propeller fighters - I'll try to experiment a bit and post my results here :-)

Regards,

Henning (HoHun)

[Badboy]

Originally posted by HoHun
Hi Badboy,

I was surprised to see they even had these diagrams, but of course, the concept of energy manoeuvrability was undiscovered yet.

Yep, and although the approach is different, the original diagrams are every bit as informative and as deserving of the “energy maneuverability” title coined by Boyd & Christie in 1964 for their more recent evolution of the same idea.  

I'd guess the reason is that jet fighters' energy manoeuvrability diagrams vary much more than propeller fighters'. Part of this is related to the fact that for propeller fighters, best turn rate and smallest turn radius coincede, while these are two different parameters for jets.

Strictly speaking, the best turn rate and turn radius for prop’ fighters don’t exactly coincide, they occur at different points in the envelope for exactly the same reason they do for Jet fighters. It is just that because the speeds are so much lower, the difference is not very significant, and for that reason almost never modelled in WWII flight sim’s.

I still believe there should be some better way of comparing (and understanding) propeller fighters - I'll try to experiment a bit and post my results here :-)

Good luck with that, I look forward to seeing your results.

Badboy