Specific Excess Power & MER | EM Diagrams Pt.1.5 | War Thunder

แชร์
ฝัง
  • เผยแพร่เมื่อ 4 ม.ค. 2025

ความคิดเห็น • 64

  • @CatWerfer
    @CatWerfer  3 หลายเดือนก่อน +5

    Typo at 1:38, should be E_T = E_K + E_P
    After doing some revising to my script, the EM Diagram I use as an example in this video is not 100% accurate, specifically the SEP contours in the middle of the graph are not angled correctly. Behavior at the edges of the plot are still accurate so everything I say in this video still holds, just if you care about shallow turn behavior, it might not be perfect.

    • @youngbloodbear9662
      @youngbloodbear9662 2 หลายเดือนก่อน

      Another great video! I will throw in a couple nitpicks here besides what you’ve addressed, but these are more an excuse to talk about it than real issues :). First, not an error just something I would have added, normally when we make a value specific or especially talk about energies, we walk in terms of mass- the reason weight is used here instead is because of units, that lets us keep everything in terms of force, thrust, drag, weight etc, for convenience to keep dimensions out of our other coefficients. This is also helpful when looking at optimization or range calculations where even fuel is calculated in terms of weight rather than mass. Next nitpick is have is a common habbit of teachers everywhere when showing an equation is to treat it as a law that causes things to happen- ex the Cd reflects the changing forces on an aircraft to model drag, it doesn’t cause the drag itself, your meaning is obviously correct that’s just a personal thing i have about staying grounded in the physical processes when learning new ideas… last thing is I just want to point out that your discussion about different ways of turning costing the same energy but being able to manifest in different forms is exactly correct from an EM point of view and gets your message across well, but this is actually where the cracks start showing! Traditional EM analysis is largely forced to rely on assuming things are static or happen instantly in a way- it’s very hard to get a full picture of a fluid scenario changing in time,in reality while turning or diving you’re still producing thrust and drag and changing energy states, and the path you take in changing your orientation affects that total both the total drag over your trajectory and how long you are producing engine power etc. You can start to see this in some EM grass such as looking at speed versus turn rate excess energy graphs. You can imagine how someone pull a hard turn and lose energy and then ride that contour down towards low speed and low turn rate, but in general complex maneuvers are almost impossible to capture in EM graphs and particularly how maneuvers chain together is a really difficult, something that wasn’t for a long time is important. It is not just to be able to go up but also down that energy as well because of those maneuvers together and how sometimes you need to be able to affect your turn radius and rate in ways that can’t be done that high energy and so Being able to both gain and lose energy is as important to be able to maintain it, which really wasn’t brought out for the first several years of EM theory being used. Last thing I think it’ll be really interesting for you to talk about is some of the climb optimization stuff that came out of Rutowski‘s workthat a lot of the early development EM came from beside John Boyce work and it’s another really interesting way to use this energy idea to do useful things through aircraft like minimize time to climb

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน +1

      @@youngbloodbear9662 fascinating, thanks for the info! Yeah the more I do tests, the more i realize that things like AoA and engine thrust output and its PID responses are very much transient behavior and (at least in game) and make it difficult to model rapid changes that happen in a dogfight.
      It's becoming somewhat problematic in treating every x,y position on the plot as though it must have just one specific excess power number.
      For now I'll stick with this but I definitely have further reading to do.
      I was also planning on doing another dive into optimizing climb, especially for aircraft that go supersonic that have to overcome wave drag, but that's farther down the line.
      Anyways, I greatly appreciate your takes, keep nitpicking my videos so i can keep learning more!

    • @youngbloodbear9662
      @youngbloodbear9662 2 หลายเดือนก่อน

      @@CatWerfer happy to haha looking forward to seeing what you come up with. I haven’t done a lot of careful testing but i can say the climb dive climb profiles do work in game and I use them in all my supersonics

  • @JSDFEnthusiast
    @JSDFEnthusiast 3 หลายเดือนก่อน +8

    What a blessing it is to have good hand writing this day n age

    • @CatWerfer
      @CatWerfer  3 หลายเดือนก่อน +2

      @JSDFEnthusiast normally it's pretty terrible lol, I just have the pen smoothness setting turned up (and I also try to make it nice and legible so I do multiple attempts).
      This is probably the first time I've had my handwriting complemented, so thanks!

    • @JSDFEnthusiast
      @JSDFEnthusiast 2 หลายเดือนก่อน +1

      @@CatWerfer pen smoothing coming in clutch in both writing and drawing, I know it all too well lmfao

  • @CatWerfer
    @CatWerfer  3 หลายเดือนก่อน +21

    Catwerfer try not to do math in a video challenge (impossible)

    • @sunshinecoco12
      @sunshinecoco12 3 หลายเดือนก่อน

      lolll

    • @sunshinecoco12
      @sunshinecoco12 3 หลายเดือนก่อน +2

      you made the joke before anyone else could

    • @hampusnilsson6950
      @hampusnilsson6950 3 หลายเดือนก่อน +1

      Love this though

    • @Wahtdehec
      @Wahtdehec 2 หลายเดือนก่อน +1

      We love the math plz don’t stop

  • @s_ziel
    @s_ziel 3 หลายเดือนก่อน +4

    Looks like drag was simplified to parasitic drag only, but there's also lift induced drag. Because of it there's high drag at very low speeds as the aircraft struggles to stay in the air at high angles of attack.
    There's also wave drag when travelling at more than transonic speeds, but it doesn't have its own equation and is just represented as an increase of coefficient of drag.

    • @CatWerfer
      @CatWerfer  3 หลายเดือนก่อน +1

      That's true, I just wanted a relatively simple explanation for the video.
      Also the Cd that I use for this video isn't zero lift drag, its the whole drag coefficient so it includes lift induced as well as skin friction and form drag.
      At the end of the day, Cd is a coefficient arbitrarily designated for an arbitrary reference area so you can really have it describe all drag if you want, itll just end up being nonlinearly dependent on AoA and all the other factors.
      The way I account for this when generating the EM diagrams is pretty simple though, you'll be able to see it soon (tm)

  • @Adrella_Highwing
    @Adrella_Highwing 2 หลายเดือนก่อน +2

    A complex topic explained in a really comprehensive way - lovely work!! 😁

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน +1

      thanks! explaining things that may seem complicated at first in a way that people can understand was my exact goal and it's very validating to hear that i accomplished it :)

  • @lukeskywalket2894
    @lukeskywalket2894 2 หลายเดือนก่อน +1

    Oh man I wish I saw this when it came out last week. I’m so happy that someone is finally taking a deep dive into the math behind the dogfights (I would do it myself but I don’t have the time)

  • @piedpiper4450
    @piedpiper4450 2 หลายเดือนก่อน +2

    hey this was truly awesome this helped solve some of my questions eagerly waiting for the next one. awesome work ❤️

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน

      yeah i saw your comment and could see how my first video was confusing a bit and i really just glossed over SEP.
      glad this cleared things up!

  • @C_Harold
    @C_Harold 2 หลายเดือนก่อน +1

    i can feel my brain getting bigger, or its a headache coming on. Either way very educational i loved it!

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน +1

      Most of this video isn't critical for what I'm going to be showing later in this series but i thought i'd make a video explaining SEP cuz i didn't do as good of a job doing so in the last vid and i'm gonna be doing more stuff using SEP later down the line after this series.
      Hopefully i explained it in a way that made sense and minimized the headache lol, glad you liked it :)

    • @C_Harold
      @C_Harold 2 หลายเดือนก่อน

      @@CatWerfer i sorta got the gist from the part 1.0 but hearing all the factors and stuff makes it make more sense to me, im excited for the part 2!

  • @puff7145
    @puff7145 2 หลายเดือนก่อน +1

    You can display SEP using WTRTI hud (along with a lot of other interesting numbers, most of which are pointless to look at in battle though)

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน +2

      there are... issues with the way WTRTI displays its variables, including SEP, I'll get into that in my next video

  • @Kiirxas
    @Kiirxas 2 หลายเดือนก่อน +2

    Great, now my thermo and fluid dynamics classes are even in WT ;-;

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน

      lmao if you want you can ignore this video, the main point is just "SEP is just how quickly your energy changes"

  • @HerraTohtori
    @HerraTohtori 2 หลายเดือนก่อน

    Technically there is another type of energy loss which mainly affects aircraft that are capable of vertical climbs (thrust-to-weight higher than one).
    Namely, gravity losses. Basically, if the aircraft starts a vertical climb at a very slow speed, it will use a lot of fuel maintaining that very low speed since the climb lasts for a long time while maintaining full afterburners. By contrast, if the climb starts at a higher speed, then the aircraft can maintain that high speed throughout the climb. This means the aircraft climbs faster, therefore reducing climb time and thus reducing the amount of fuel spent during the climb.
    This is more generally known as the Oberth effect, and while it mostly affects things like spacecraft, there are parallels to aircraft as well. In general, flying at high speed increases the efficiency of a reaction engine - but it also explains things like why pulling high AoA to achieve a specific deceleration at high speed for 5 seconds loses a lot more energy than experiencing same deceleration at low speed for the same 5 seconds.
    In both cases, the speed loss is the same, but since the drag force does work to slow down the aircraft, the energy loss is the drag force multiplied by distance traveled.
    And since you travel a longer distance in 5 seconds at high speed, than you do at low speed, that basically explains why high drag at high airspeed is so detrimental to your energy state.

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน

      huh i didnt know about that, ill have to read about it.
      probably won't affect prop planes too much right?
      Do you think gaijin would model this? or is this something that is just a manifested phenomenon and would already exist without needing explicit implementation?

    • @HerraTohtori
      @HerraTohtori 2 หลายเดือนก่อน +1

      @@CatWerfer There's no particular need to "model" this.
      In fact if you think about it, concepts like "energy" and "work" are entirely unmodeled in most physics engines. They are concepts that emerge naturally from a very simple physics framework, and we can then use them to describe the simulation just like we can use them to describe reality.
      If you have a physics engine where objects have mass, and you can apply forces to those objects and those forces result in accurate accelerations causing the objects to move, you already have enough to "model" energy and work without any additional programming.
      The energy losses I'm talking about are related to the fact that in physics, a force is only doing work if it's causing movement against a resisting force, be it drag or gravity or whatever.
      So if you have a plane that is strapped to the ground (or a carrier deck) and you set the engines on full afterburner, they certainly consume massive quantities of fuel, but the plane isn't *doing* anything to increase its mechanical energy state. So all of the chemical energy converted into thrust is lost as heat, noise, and movement of the air around the nozzle. This represents the peak of inefficiency.
      If you turn the plane into vertical orientation and assume that it is hovering at zero speed, using its engines to exactly counter gravity - physically this is identical situation because the sum of forces acting on the plane is zero. This means the plane isn't climbing, nor is it accelerating - it's just hovering there at static altitude, using all of its fuel just to stay still. This represents the peak of those "gravity losses" I mentioned, where all of the fuel is wasted fighting gravity instead of increasing the plane's altitude.
      Now if we want to put numbers onto this phenomenon, let's imagine that you're in an F-15 that has exactly 1.0 TWR. We're also going to ignore the fact that air drag increases approximately proportional to the square of airspeed, and just assume that the aircraft can simply maintain "zero acceleration" upward regardless of its airspeed. It's a simplified example, so we're just assuming that during the climb the aircraft's kinetic energy stays constant.
      If the plane is doing the above "hovering" with its nose simply pointed up but not gaining altitude, that means it's not gaining any potential energy. All of the energy released by the engines is wasted and none of it is useful for the plane.
      But if you start the climb flying at let's say 120 knots, you will _maintain_ that speed during the climb. That means, it takes about 50 seconds to climb 10,000 ft. The fuel concumed is the fuel flow rate per second, multiplied by the time it takes to climb, so the engines consume some amount of fuel during this 50 seconds of climb.
      Now, if you increase your initial airspeed and start the climb at 240 knots, the plane will also maintain that speed during the climb. So now climbing to 10,000 ft will only take about 25 seconds, and that means fuel consumption is halved.
      That's basically what Oberth effect is. If you are flying faster, a reaction engine can convert fuel into mechanical energy at much higher efficiency, even if the thrust of the engine stays constant.
      In practical terms this means that if you're doing a zoom climb, it's better to do it at the highest possible speed because that means you end up using less fuel during the climb.

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน

      huh yeah ok. for now I'm limiting my scope to subsonics since specific excess power curves aren't a fan of supersonic drag, and that regime is a lot harder to test.
      This probably won't have a noticeable affect on props right? the only prop I know that has a very fast fuel consumption rate is the spitfire LFmk9 and other planes with 150octane...
      Have you tested any of this to see whether these effects present a significant enough difference to account for ingame?

    • @HerraTohtori
      @HerraTohtori 2 หลายเดือนก่อน

      @@CatWerfer For fixed-wing aircraft with TWR much less than one, it's not a very relevant term of energy loss, because obviously they cannot maintain constant speed in a climb - if they climb at a very steep angle, it's mostly a matter of converting kinetic energy to potential, since gravity is usually significantly stronger than the engine's thrust.
      For propeller-driven aircraft it's doubly irrelevant because the thrust of the propeller is highly dependent on airspeed, much more so than with reaction engines. The fact that thrust is lost when airspeed increases kind of means these aircraft don't have large enough flight envelope for gravity losses to really become apparent or meaningful.
      Theoretically, however, it is a valid form of energy loss for flying objects, and it leads to some interesting considerations when you apply the same thought to other forces. This same effect is very much apparent when you consider the inverted situation where high drag is applied to the airframe at different speeds. This is b basically the reason why maneuvering hard at high speed consumes so much more energy than maneuvering at low speed.
      That said, gravity losses are _usually_ something that mostly concerns things like orbital rockets and finding the optimal trajectory so that you can spend most of your delta-v in actually increasing the rocket's orbital velocity instead of slowly rising from the launch pad.

  • @KingCrumBum
    @KingCrumBum หลายเดือนก่อน

    Yeeeees! I fuckn LIVE to find channels like this. Lol for real things for your work. I have this on trying to set up but I get lost in your videos lol

    • @CatWerfer
      @CatWerfer  หลายเดือนก่อน +1

      thanks! workin on another technical video comin soon (tm)

    • @KingCrumBum
      @KingCrumBum หลายเดือนก่อน

      @CatWerfer I'll be watching

  • @benbased7740
    @benbased7740 2 หลายเดือนก่อน +1

    Man you're like AdamTheEnginerd reborn❤

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน +1

      @@benbased7740 i do my best!

  • @Alpakinator
    @Alpakinator 2 หลายเดือนก่อน

    When WT addiction makes you do math, it's not the worst addiction in the world.

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน

      can't wait to get into "socioeconomic theory thunder" and "philosophy thunder"

  • @Kenionatus
    @Kenionatus 2 หลายเดือนก่อน

    It took me a bit to realise that the unit of the SEP is the rate of height gain, not a speed difference.

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน

      @@Kenionatus yeah, it's a kind of weird unit of energy, I could've explained it better, but I was also a little confused by it too

  • @daber6948
    @daber6948 3 หลายเดือนก่อน +1

    Finally somebody explained those concepts in detail. That's so usefull and interesing tool. Are there any database with war thunder em diagrams? I have trouble finding some googling as usually

    • @CatWerfer
      @CatWerfer  3 หลายเดือนก่อน

      @daber6948 no, there is no database (yet), its kinda difficult to make them if you don't know what you're doing. Ill try to explain what I do in my next vid

  • @Macintoshiba
    @Macintoshiba 2 หลายเดือนก่อน

    Now I know all of this but I still cant transform 7 minutes of climbing to altitude into a match to actually be worth it

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน

      I'll be doing an application video soon

  • @nathanski9268
    @nathanski9268 2 หลายเดือนก่อน

    *Yak-3 turning on intercept path with your BF-109 F-4 from 3 o’clock low*
    “Hold on let me refer to my EM chart before we start this turn fight.”
    In all seriousness I love these videos. Are you an engineer or physicist?

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน +1

      lmao, bring out the aircraft encyclopedia with each page containing every possible combination of two aircraft fighting.
      I'm studying engineering, though the exact material in these videos are not my immediate field of study.
      It seems there are actual aero engineers in my comments correcting me when I say something silly, which is pretty awesome

    • @nathanski9268
      @nathanski9268 2 หลายเดือนก่อน

      @@CatWerfer energy fighters are my favorite :)
      Yea I’ve seen a few of these corrections and it’s pretty insane. Please keep making videos. Very worth watching.

  • @dangernoodle235
    @dangernoodle235 2 หลายเดือนก่อน +1

    Did you study physics or engineering haha
    Cause much of that stuff I recognise straight out if my physics lectures

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน +1

      lol yeah i study engineering, though a lot of the stuff here is stuff i learnt outside of classes

  • @EphVT
    @EphVT 2 หลายเดือนก่อน

    I WAS THE 100TH LIKE, WHERE ARE MY CATWERFER BUCKS

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน

      catwerfer is busy paying off student loan debt

  • @KekusMagnus
    @KekusMagnus 3 หลายเดือนก่อน

    If it's not too much work, you should also fill in the "climbing" part of the graph, it is occasionally used in dogfights

    • @CatWerfer
      @CatWerfer  3 หลายเดือนก่อน

      the reason why it looks empty is because the contour lines arent fine enough, everything on that side is below 25m/s SEP, and the maximum is reached at ideal climb, at about 20m/s SEP. I could make the contours finer for just that side, but i'd have to figure out how to do that

    • @KekusMagnus
      @KekusMagnus 3 หลายเดือนก่อน

      ​@@CatWerfer Oh, right lmao

  • @ZI0mek
    @ZI0mek 3 หลายเดือนก่อน

    For people who would prefer warthunder to be a spreadsheet (very interested)

    • @CatWerfer
      @CatWerfer  3 หลายเดือนก่อน

      i mean i like learning to fly planes, but its really hard to get any sense of how well they fly without actually testing it and that can be kinda stupid

    • @ZI0mek
      @ZI0mek 3 หลายเดือนก่อน

      ​@@CatWerfer exactly, the game gives very little information and I couldn't find anywhere else either

  • @HeyImKatyusha
    @HeyImKatyusha 3 หลายเดือนก่อน

    i have to say, overall its all right what you say, but it has no point if you don't show examples specific for the game. otherwise its more of a physics class, than a example that can help you in the game

    • @CatWerfer
      @CatWerfer  3 หลายเดือนก่อน +1

      thats why this is a 3.5 part series lol

    • @HeyImKatyusha
      @HeyImKatyusha 2 หลายเดือนก่อน

      @@CatWerfer but it make more sense to make 1 video then instead of 5?
      nobody likes to watch 5 videos after another in complex topic and then with delay cause they come out after another.
      it would make way more sense to make 1 big video so the viewer doesn't need to click through your content and could understand everything without break. but that's just a friendly advise from me

    • @CatWerfer
      @CatWerfer  2 หลายเดือนก่อน +1

      maybe you might not want to but for people who are interested, they'll be back.
      I'm also not 100% done in terms of being satisfied with the way I want my data to be presented so I want to do a bit of cleanup work before I present it.
      TBH it might be another week until i get ready to post the results.
      I'm also a video editing newb (my videos are literally powerpoint slideshows lol) so it takes a while for me to make these videos, and with a non-gaming laptop as crash-prone as mine, its good to work on projects in smaller chunks to minimize the chance of losing progress.
      Maybe I'll make a full series compilation video at the end where i just splice everything together, but this is more manageable to me.

    • @Juhziz
      @Juhziz 2 หลายเดือนก่อน

      @@HeyImKatyusha I sure do.

  • @OperatorMitch
    @OperatorMitch 3 หลายเดือนก่อน +1

    holy fuck this is too 5Head for me

    • @CatWerfer
      @CatWerfer  3 หลายเดือนก่อน +2

      i mean tldr is "SEP measures how quickly you gain or lose energy when doing a turn", as long as you got that you're good