Aces High Bulletin Board
Help and Support Forums => Help and Training => Topic started by: PJ_Godzilla on March 31, 2011, 12:28:32 PM
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Gents, Does anyone know if Badboy maintains a repository (or perhaps suppository) of E-M comparisons? I've seen a link recently to his E-M page but saw no link to the oft-reffed "calculator" or any such repository. Badboy knows his stuff and I'm looking for a couple of specific E-Ms.
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Badboy has not published all his data but this should be a good link for his calculator if you want to do your own flight testing.
http://www.leonbadboysmith.com/Files/AH_BootStrap.zip
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I'm looking for a couple of specific E-Ms.
Which ones are you looking for?
Badboy
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Which ones are you looking for?
Badboy
I really want one for the 109s G-14/K4 and for the Ki-84 and N1K2. Ideally, I'd get one for the 38, Spit 16, P-51B/D and La as well... I n tha torder of priority.
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I really want one for the 109s G-14/K4 and for the Ki-84 and N1K2. Ideally, I'd get one for the 38, Spit 16, P-51B/D and La as well... I n tha torder of priority.
I would really love to see one for the 109G-14, 109K-14 and Spit 16 as well, if possible.
I've been flying the k-4 for a while in the DA and most people seem to love the spit16 in there, which I have a hard time flighting against. Maybe I have to learn to extend more for reversal room or something but I'd like to see what the numbers say for what would give me the best edge.
Thanks Badboy!
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I would really love to see one for the 109G-14, 109K-14 and Spit 16 as well, if possible.
I've been flying the k-4 for a while in the DA and most people seem to love the spit16 in there, which I have a hard time flighting against. Maybe I have to learn to extend more for reversal room or something but I'd like to see what the numbers say for what would give me the best edge.
Thanks Badboy!
Funny, but I noticed, the other night, that it was fairly easy to extend away from a Spit-14 and some Hawgs in the K-4. The real problem I have with that machine is dealing with turners. I've been practicing lag rolling but all this eems to do for me is maintain some position above and behind from where I'm too far out to take a shot. It seems like, no matter what, I'm either taking hopeless high-speed tater shots or saddling up and making myself extremely vulnerable. The whole right-side energy fight is thus baffling to me. I mean, what the hell good is a D-9 at 400kts if you can never land a shot? All you get is a snap at that speed, typically.
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The Dora's guns and airframe combination never made sense to me. Put an MK108 or MK103 in the nose instead and..
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Badboy, would it be possible to make diagrams for the ww1 planes? That would be much appreciated by me, and I am sure by everyone else that plays around in that arena.
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I really want one for the 109s G-14/K4
Ok, this will get you started.
The performance is very close. The analysis of their performance with flaps shows that these two aircraft are similarly closely matched as flaps are employed.
(http://www.leonbadboysmith.com/images/K4vG14.gif)
The data for the G-14 is a bit dated, but should be ok. With performance this close I would expect an engagement to be decided by something other than turning ability. Of course, the G-14 might have the additional Gondolas, or one or other aircraft might have more fuel, and that could swing it. For example, if the G-14 had the Gondolas and 25% more fuel its sustained turn rate would drop by two degrees per second across the envelope and that could be decisive performance hit. Give the K4 25% more fuel and its sustained turn rate drops one degree per second below the G-14. Either way these aircraft are still closely matched and factors such as pilot ability, aircraft handling, fuel or configuration differences and possibly other performance factors are likely to have a more significant influence on the outcome.
Badboy
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Badboy, I'm curious as to what type of software/data you use to generate these graphs?
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Ok, this will get you started.
The performance is very close. The analysis of their performance with flaps shows that these two aircraft are similarly closely matched as flaps are employed.
Flaps? I reckon those would only impact the left-hand (low-speed) extent of the envelope, right? I mean, corner speed is corner speed and lies above the speed at which you can extend flaps anyway...
Otherwise, thanks. Increasing alt tends to shift this all to the right, yes?
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Flaps? I reckon those would only impact the left-hand (low-speed) extent of the envelope, right? I mean, corner speed is corner speed and lies above the speed at which you can extend flaps anyway...
Otherwise, thanks. Increasing alt tends to shift this all to the right, yes?
Many things are a factor in affecting turn rates. Altitude wouldn't be one of those as the speed is measured in indicated mph and that won't change with alt. The relative speed of the wind across your wings is what it is. But with thinner air up high you have to be moving faster through it to produce that. Alt will affect your engine's ability to produce a certain speed or not, however. Other factors include things like notches of flap if any, WEP on or off, and weight of fuel/guns/ords The corner speed in Badboy's diagrams are for one particular configuration, in the above case that would be 25% fuel, clean (no flaps or gondies etc) and at sea level. Change that configuration and the corner speed will move correspondingly.
Most people think that corner speed is etched in stone. That there's a set best turn speed and that's just not the case.
Drano
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Many things are a factor in affecting turn rates. Altitude wouldn't be one of those as the speed is measured in indicated mph and that won't change with alt. The relative speed of the wind across your wings is what it is. But with thinner air up high you have to be moving faster through it to produce that. Alt will affect your engine's ability to produce a certain speed or not, however. Other factors include things like notches of flap if any, WEP on or off, and weight of fuel/guns/ords The corner speed in Badboy's diagrams are for one particular configuration, in the above case that would be 25% fuel, clean (no flaps or gondies etc) and at sea level. Change that configuration and the corner speed will move correspondingly.
Most people think that corner speed is etched in stone. That there's a set best turn speed and that's just not the case.
Drano
I disagree. My understanding is that the E-M is alt-specific. You cite the reasons why above but let's reiterate:
1. rho changes - therefore, anything rho-dependent changes - this includes lift and drag.
2. power output, and with it, powerloading changes.
3. max speed changes (true) - note that this alone would increase the size of the envelope, not to mention any other effects. Thus contradicting any assertion that the E-M won't change with alt.
As for your assertion that "altitude wouldn't affect turn rate" because speed is in indicated mph and since this won't change with alt, neither will the e-m I found it baffling, perhaps just because of how it was written. Indeed, see Shaw, page 300. He states that corner WILL change with alt but that shoudl be relatively insignificant if we express indicated instead of true. He says no such thing about the e-m diagram of which corner velocity is but a part (if a critical one).
However, your intuitive statement about the speed/alt dependency of lift is correct.
Then, your last statement appears to contradict your earlier assertion - so you leave me a bit baffled.
Finally, yes, I'm aware that Badboy has outlined one config - it is on the plot. However, I wold also point out that he's clearly indicated that this is at SSL alt and state.
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And, I almost forgot to add, thanks and praise be unto Badboy. I figured that corner speed was a nose-low 225-250 in the beloved G-14 because I remember a magic moment at that speed and attitude in which I was outturning a lala. Clearly, under the right conditions and loadout, he should be able to outturn me - but it's close and, at the margin, little things like a slight weight edge - or perhaps alt, make a diff.
Badboy, can you say a few words on the trend impact of alt? - outside of the obvious and aforementioned top speed line increase.
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and for the Ki-84 and N1K2.
I just found an analysis I did of the Ki-84 v Spit16 a while back and I don't think I ever posted it.
Firstly I looked at the Sea Level performance with 25% fuel for both aircraft and it came out like this:
(http://www.leonbadboysmith.com/images/Ki84vSpit16_1.gif)
Which shows a clear advantage to the Spitfire at lower speeds where it has a slightly tighter sustained turn and a sustained turn rate advantage of about two degrees per second which would be decisive. The problem is that if you meet a good Ki84 pilot on line in a Spit16 the outcome will be anything but decisive. So, what happens when the Ki84 and Spit employ flaps?
(http://www.leonbadboysmith.com/images/Ki84vSpit16_2.gif)
Now the Ki84 can match the Spitfire's instantaneous turn performance very closely. Now let's see what happens when the Ki84 employs two notches of flaps:
(http://www.leonbadboysmith.com/images/Ki84vSpit16_3.gif)
Here the instantaneous performance of the Ki84 exceeds that of the Spitfire by around five degrees per second, speed for speed, in terms of air combat that is a very big advantage. But then of course the Spitfire pilot will employ his flaps also, and when both aircraft have their flaps extended their performance looks like this:
(http://www.leonbadboysmith.com/images/Ki84vSpit16_4.gif)
This shows that the Ki84 retains a sustained turn advantage of around two degrees per second while their turn radii are similar.
You can see from this that an engagement between these two aircraft will depend a lot on each pilot's ability to use flaps correctly, and the Ki84 has the ability to gain speed rapidly when nose low, which gives it the ability to hold energy better than the Spitfire, particularly in vertical fights or fights where the Ki84 makes good use of the vertical plane, combined with good use of flaps. This can all result in a fight that can go either way, the Ki84 with good use of the vertical and flap employment that tends towards lead pursuit at the top in the vertical, and lag pursuit at the bottom, and similar flap usage in Hi Yo-Yos. For the Spitfire pilot this will always be a difficult fight, unless the Ki84 fails to fly to its strengths.
As a disclaimer, I would add that those diagrams date back to version 2.12 patch 4 and while they may or may not match the current version my recent experience indicates that the conclusions are still valid.
Badboy
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Badboy, you've raised the specter of something I was thinking about just yesterday. EM works in the horizontal plane where grav force is constant. Yet we all know that there are two (principal) planes in which to maneuver. However, because, in the vertical plane, the grav force is constant but the lift vector is rotating from aligned to grav to opposite of grav and alt is variable as well, the analysis is trickier. Have you seen/has anyone done any solid analysis work on minimal loop circles?
It seems to me that you'd actually have a stretched (biased - larger radius at bottom where the speeds are higher) ellipse on the vertical and that, while it wouldn't make sense to talk about "turn rate" (because variable throughout maneuver) it might make sense to talk about angular displacement over a given time window. Again, you'd have at issue whether the loop was energy neutral or an energy sink, since you could probably tighten the top and bottom radii by converting speed. This'd clearly be an integral in time of the rate of angular displacement expressed in time-dependent expressions, itself dependent on the same physicals you see in horizontal, just recast to allow them to be f(t).
Otherwise, thanks for this analysis. The thing that I'm sturck by about this is that it's a race to the bottom. They're both going to want to start at corner but invariably will end up low and slow and popping flaps, at least if the knife-fight lasts that long and stays horizontal. OTOH, both have solid accel and climb rates - and somebody might do something dumb.
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Then, your last statement appears to contradict your earlier assertion - so you leave me a bit baffled.
You're right I did. That's what happens before coffee. :)
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Thanks Badboy! :cheers:
I too have a question regarding the vertical eliment, and not sure exacly how the physics plays out so I'm hoping someone here can aid me in properly visualizing this.
If I'm in my 109K and coming down from a vertical, and the enemy plane climbs up into my dive/decent, when (or at what speed) should I pull back on my elevaters and return going vertical? I know that gravity is working against me getting my nose back up above the horizon, so I'm wondering how fast/slow I would need to be in order to reduce the time it takes for me to get my nose back up. Would it be closer to the max corner velocity (as in turning just before I reach it, knowing that I accelerate in my decent) or do I want to turn back up into the vertical at a much slower speed?
OR, is the answer "as soon as possible" in order to reduce the chanse of the enemy reversing onto my six to gain angles? I hope my hypothetical situation is written in a mannor that makes some sort of sense.
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Badboy, can you say a few words on the trend impact of alt?
You can see the general trend by looking at a set of diagrams I did some time ago for a Battle of Britain Scenario. This set shows the performance in 10,000ft increments.
(http://www.leonbadboysmith.com/images/BoB1.gif)
(http://www.leonbadboysmith.com/images/BoB2.gif)
(http://www.leonbadboysmith.com/images/BoB3.gif)
(http://www.leonbadboysmith.com/images/BoB4.gif)
You can see that typically, the turning ability of all the aircraft is degraded at high altitudes in terms of their turn rates and radii.
You notice in the last diagram these aircraft hit their top speed at that altitude before they can reach their 6g corner velocity, in effect they can't pull enough G so their corner velocity is defined by their lift limit. The Bf110c for example can just make 5g at top speed, and can only sustain about 1.3g. In general their sustained turning ability will depend on engine performance at altitude.
Usual disclaimer... those diagrams are dated, and while the trends are typical, they may no longer be accurate representations of current AH aircraft.
Badboy
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Do you guys notice something, the people asking about how to deal with spit16s in a k4?
Look at the sustained turn rate and at what speed
(http://www.leonbadboysmith.com/images/K4vG14.gif)
(http://www.leonbadboysmith.com/images/Ki84vSpit16_1.gif)
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Hint....
The corner velocity and the sustained are very similar in both the k4 and the spit16 but...
1) How fast can you change 'e' states in each ride?
2) How many notches of flaps do you have?
3) How fast can you go before you get a notch (or two) out?
4) Is there a speed at which the k4's dps is greater than the spit 16s?
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Do you guys notice something, the people asking about how to deal with spit16s in a k4?
Look at the sustained turn rate and at what speed
First, it looks to me like the k4 will own the Spit at 300 plus, since this looks to be roughly where it's sustained turn rate outstrips the rate of the Spit. The K4 is definitely the "energy" fighter, the Spit the angles fighter.
As for your hint, I'm not sure which has better energy income... certainly the K4 has huge mass-specific power but so does the XVI, which is well known for accel. As for the flaps, I think it's still a losing bet for the K4. They won't even pop until 195, and that's just the first notch. OTOH, it also looks like the Spit's first notch won't come out 'til about 180. So, perhaps you could exploit that window for a quick turn 'til decel/pop a notch/maneuver/fire/split using the DB's massive power? My only question w/r this "theory" - is what kind of instant or sustained turn perf you can get with one notch on a K-4 - because clean at that speed, the Spitty owns at least a couple of deg/sec sustained or instantaneous turn rate advantage.
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I have a few comments.
A sustained turn difference of 4 dps is not close.
Note the differences in turn radius.
A Spit at 300mph isn't going to stay at 3 Gs in a turn fight with a K4 when it can increase it's turn rate and decrease it's radius by pulling harder and slowing down.
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Ok....
So here is the deal.....
1)Most of the time, a 109 can LOOSE its energy faster than a spit, which means you can get to corner faster.
2) Once there strive for the snap shot. Also, a spit only has 1 notch of flaps, full or none, which means in a 109, drop one notch, at almost 200, force the spit to drop flaps (all flaps as he only has one notch), then climb out or enter a steep vert rolling scissors eeking out every drop of e you have. The act of forcing him to drop full flaps, will burn his e much faster than you, giving you a noticeable speed difference. Oh and look, a k4 can get back to corner very fast from 195 to 230 in no time, where the spit has prob will have to go from 150 - 230ish. Now, some of the best pilots will just lag turn in the spit, but most will pull as hard as they can with everything they got as they put faith in relying on their turn abilities.
3) If fight gets slow and your not on top, dive out and repeat.
4) Lastly, spits dive better than k4s, so get into a nose down vert scissors, (drop full flaps, cut throttle), chances are, the spit will not do everything and overshoot as he accelerates better and retains e better nose down. (Poor e retention is a double edged sword).
Next time in the ma, do this... as a test... (this is not a good strategy as a acm but it proves my point)
1) Get a spit on your 6 and dive with him following... ( make sure he is close, within ~400, so once you see him drop your nose down steeply, full wep, etc)
2) Once at 300 ( hopfully before he shots you), level out and cut throttle, and do as hard as you can, turn to the left. Also, make sure to throw some rudder in there to keep the 'ball' in the center.
3) watch him overshoot as he trys to follow you in the turn.
Why this works: 109 retains e much worse than a spit, so get to corner faster and your turn is tighter.
A Spit at 300mph isn't going to stay at 3 Gs in a turn fight with a K4 when it can increase it's turn rate and decrease it's radius by pulling harder and slowing down.
And when he blows his 'e' to pull for lead, go for 'e' and climb!... you have the same climb rate as him (if not a tad better) and from the spits perspective, you will disappear! (as he has pulled lead for the shot, so you under his nose, in which case you roll and pull up, and he wont see you do it)
I'm sure FLS can elaborate more on this.
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You can describe any outcome you like. :D
Those EM diagrams show you that you don't want an even fight on the deck in a K4 against a Spit 16.
I expect the better pilot will usually win in any case. :joystick:
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Badboy, would it be possible to make diagrams for the ww1 planes?
Hi Urchin
Here is what comes out of the BootStrap Calculater for the WWI aircraft, all at Sea Level with 25% fuel. The diagrams show the turn radius and turn rate graphically so you can picture the geometry of a fight between the aircraft.
(http://www.leonbadboysmith.com/images/WWI_I.gif)
(http://www.leonbadboysmith.com/images/WWI_S.gif)
Hope that helps...
Badboy
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Thanks Badboy. The F2b is surprisingly good against the DVII.
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You can describe any outcome you like. :D
Those EM diagrams show you that you don't want an even fight on the deck in a K4 against a Spit 16.
I expect the better pilot will usually win in any case. :joystick:
Agreed equal pilots in a turn fight, spit 16 wins. K4 is much faster so k4 pilot could bnz the spit to death. Either way, my point was that because the spit has a tighter and more dps sustained turn, probably means that it doesn't burn as much e making an instantaneous turn and thus recognizing this and using it against the spit is the key.
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Ok....
1) Get a spit on your 6 and dive with him following... ( make sure he is close, within ~400, so once you see him drop your nose down steeply, full wep, etc)
2) Once at 300 ( hopfully before he shots you), level out and cut throttle, and do as hard as you can, turn to the left. Also, make sure to throw some rudder in there to keep the 'ball' in the center.
3) watch him overshoot as he trys to follow you in the turn.
And when he blows his 'e' to pull for lead, go for 'e' and climb!... you have the same climb rate as him (if not a tad better) and from the spits perspective, you will disappear! (as he has pulled lead for the shot, so you under his nose, in which case you roll and pull up, and he wont see you do it)
I'm sure FLS can elaborate more on this.
I like either of these. I have to admit, most of the time I just avoid Spits in either G-14 or K-4, beyond making the occasional high-speed firing pass. It's very bad to get caught low and slow by one. The tricky thing with both of these tactics, as with the rope so frequently useful against poorer-climbing AC than Mr. Spitty, is that they start from a position in which you can get shot. However, the tight turn folowed by roll-to-level and pulling up strikes me as particularly good since it puts you in a position in which you can use roll to put your lift vector back onto the Spitty from above, possibly getting, from there, a snap opportunity. I'm assuming that, at low enough alt, I can do the same in a G-14. Looking at the comparison, I'd say a similar tack will work, assuming I'm sans gondolas (more and more these days).
I guess I'd also think that the roll-to inverted and dive away might be a decent way to disengage, though the drooling easy-mode jockey will doubtless come around and still have some speed with which to follow. I always like the K-4's extension capabilities and even the G-14 ain't bad at it. That's probably enough for Mr. Spitty pilot to say, "duuuuh I got to yank da stick... duuuuuuh."
I've learned to love the Zero in AvA this week but, let's face it, this constant meat-pulling thing doesn't require much upstairs. Spitty is therefore sort of like a cheap hooker or an airline seat - any smecking, leering idiot can enjoy one at a low price. That's not to say there aren't some really good Spitty jocks.
Also, I think Badboy has just documented a big part of the reason why the LW's switch to bombing London was so disastrous in the BoB. In the hands of average pilots, the LW set is overmatched.
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Badboy, thanks!
What information do the e-m diagrams show that those turning circles don't? I'm curious if there is some tool that may help me identify an area that the camel has an advantage over the dr1. Thanks again Badboy.
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Badboy, thanks!
What information do the e-m diagrams show that those turning circles don't? I'm curious if there is some tool that may help me identify an area that the camel has an advantage over the dr1. Thanks again Badboy.
Not an all inclusive list but here are several big things like...
1) corner speed & max turn performance (not sustained)
2) relative difference in energy margins between aircraft (this is the most significant one in this list I think that you can exploit)
3) lift limit (speed & g's at which accelerated stall occurs)
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Not an all inclusive list but here are several big things like...
1) corner speed & max turn performance (not sustained)
2) relative difference in energy margins between aircraft (this is the most significant one in this list I think that you can exploit)
3) lift limit (speed & g's at which accelerated stall occurs)
Creating wingtip stalls is the key to rolling fast in a 109 when slow (so is engine torque).
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Ok....
So here is the deal.....
1)Most of the time, a 109 can LOOSE its energy faster than a spit, which means you can get to corner faster.
2) Once there strive for the snap shot. Also, a spit only has 1 notch of flaps, full or none, which means in a 109, drop one notch, at almost 200, force the spit to drop flaps (all flaps as he only has one notch), then climb out or enter a steep vert rolling scissors eeking out every drop of e you have. The act of forcing him to drop full flaps, will burn his e much faster than you, giving you a noticeable speed difference. Oh and look, a k4 can get back to corner very fast from 195 to 230 in no time, where the spit has prob will have to go from 150 - 230ish. Now, some of the best pilots will just lag turn in the spit, but most will pull as hard as they can with everything they got as they put faith in relying on their turn abilities.
3) If fight gets slow and your not on top, dive out and repeat.
4) Lastly, spits dive better than k4s, so get into a nose down vert scissors, (drop full flaps, cut throttle), chances are, the spit will not do everything and overshoot as he accelerates better and retains e better nose down. (Poor e retention is a double edged sword).
Next time in the ma, do this... as a test... (this is not a good strategy as a acm but it proves my point)
1) Get a spit on your 6 and dive with him following... ( make sure he is close, within ~400, so once you see him drop your nose down steeply, full wep, etc)
2) Once at 300 ( hopfully before he shots you), level out and cut throttle, and do as hard as you can, turn to the left. Also, make sure to throw some rudder in there to keep the 'ball' in the center.
3) watch him overshoot as he trys to follow you in the turn.
Why this works: 109 retains e much worse than a spit, so get to corner faster and your turn is tighter.
And when he blows his 'e' to pull for lead, go for 'e' and climb!... you have the same climb rate as him (if not a tad better) and from the spits perspective, you will disappear! (as he has pulled lead for the shot, so you under his nose, in which case you roll and pull up, and he wont see you do it)
I'm sure FLS can elaborate more on this.
First off, Ardy is one of my my 109 Heroes! I have not mastered the bird, but his advice helps out a lot in combat. It can be very tricky to pull this move off (especially near a furball or in the DA), a decent spitsteen jock will plan for this move and fake a lead, so you have to be very very careful. It's tricky to try and hang a spitsteen also, if he does follow you up, but you can also try and get him to do a vertical overshoot if you feel that he might have just enough E to get him past you (again, this is tricky, I usually get shot down more often than it works, but it's nice when it does work :x)
Badboy, thanks!
What information do the e-m diagrams show that those turning circles don't? I'm curious if there is some tool that may help me identify an area that the camel has an advantage over the dr1. Thanks again Badboy.
I've noticed that the Camel can do an amazing low yo-yo (forget if it's better to the left or right), which can cut a corner on the Dr1 for a snapshot. It also feels like it can roll better, so you might be able to out roll it in a siccor. I have a bad habit of stalling out the WWI planes in the vertical, which is very bad against a Dr1, they turn so quick that they'll likely get a shot on you before you can nose-forward, unless you time it just right.