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Bushmanni

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Posts posted by Bushmanni

    F-15C WVR

    in F-15C for DCS World

    Posted

    Forcing the other guy defensive is the number one priority in WVR fight (just like in BVR) and you do it by pulling your guns and missiles to bear on him first. He's turning ability or energy doesn't matter when you get positional advantage as unless he performs effective (bleeding energy and angles) defensive maneuvers he's toast. Saving energy just sets you up as the defensive guy. I'm not advocating bleeding all the energy in the first turn but positional advantage is better than energy advantage as you can then force the other guy to lose his energy with defensive maneuvers or shoot him down if he fails to go defensive.

     

    Eagle can stay in Flankers six no problem until he gets the kill (same applies to Flanker behind Eagle) if the pilot can do the things Stuge mentioned and also avoid overshoot (Don't get too close, slow down if you need to.). The only option for Flanker to escape is out-turning the Eagle but that makes the Flanker relatively easy target. If you can't shoot him down when he makes a break turn you are in for role reversal.

     

    The attack window entry by lag turn is mostly useless against Flanker as unless you can threaten the Flanker to constantly jink using guns you can't keep up the turn with him and you end up defensive yourself. If you end up in a situation against a Flanker where you might use lag turn you are better off with taking the snap shot opportunity and then bugging out (unless the bandit needs to be finished off after the snap shot).

     

    This also gives a good rule of thumb for the Eagle for merge criteria against a Flanker. If you can't start the fight from positional advantage (ie. threaten him with your weapons while the Flanker can't threaten you) you should bug out before the fight even starts as the Flanker will get the positional advantage before you and all your energy is useless or even a liability after that.

     

    AI flankers can be shot down with simply turning hard towards them and then gunning them down. All you need to do is to not bleed your speed below 250kts. The hard turn approach is most effective with 1-circle flow (turning towards the nose of the bandit ie. in the same compass direction after merge) as the AI likes to preserve his energy regardless of position.

    F-15 radar elevation

    in F-15C for DCS World

    Posted

    When the elevation setting is centered to zero degrees, scan cone is 10 degrees high. I have calculated that the max elevation gives a +-35 degree limit to the cone edge. At max elevation the scan cone is only little over 7 degrees while it should be still 10 degrees. At 15nm this makes 7000 feet difference in covered altitude (16k feet vs 23k feet).

    S_EVENT_HIT registers in SSE only when host is the initiator

    in Multiplayer Issues

    Posted

    I made a mission with invulnerable planes to practice gunnery and a script that tells when you hit someone. The problem is that only shots by the host trigger the S_EVENT_HIT event. Hit event is registered in the debrief.log also for clients but not in SSE environment. I have attached the mission.

     

    messages = {};
refreshrate = 1; --in seconds

function addMessage(msg, duration)
   table.insert(messages, msg);
   mist.scheduleFunction(RemoveMessage, {msg }, timer.getTime() + duration);
end;

function RemoveMessage(msg2)
   for i, tablemsg in ipairs(messages) do
       if tablemsg == msg2 then
           table.remove(messages, i);
           break;                
       end;
   end;    
end;

function ShowMessages()
   local messages = mist.utils.deepCopy(messages)
   local output = "";
   
   for i, val in ipairs(messages) do
       if i == 1 then
           output = val;
       else
           output = output .. "\n" .. val;
       end;
   end;
   
   if output ~= "" then
       trigger.action.outText(output, refreshrate);
   end;
   mist.scheduleFunction(ShowMessages, {}, timer.getTime() + refreshrate);
end;

ShowMessages();

customEventHandler = {};

function customEventHandler:onEvent(event)
   if (world.event.S_EVENT_HIT == event.id) then
       local target = "unknown";
       if event.target:getCategory() == Object.Category.UNIT then
           if event.target:getPlayerName() then
               target = event.target:getPlayerName();
           elseif event.target:getName() then
               target = event.target:getName();
           end;            
       end;
       addMessage(target .. " was hit", 5);
   else
       addMessage("event id = " .. event.id, 20);
   end;
   
end;
world.addEventHandler(customEventHandler);

    PvP snap shot drill BFM training 4x pairs.miz

    • Thanks 1

    The AH-64 Apache Thread

    in Military and Aviation

    Posted · Edited by Bushmanni

    And I have heard that before too. And that the rotors would explode if they did go supersonic and yet I have also heard that the Huey rotor tips DO go supersonic and the distinctive Whop-Whop sound is due to the rotors breaking the sound barrier...

     

    Hmmm. So which one is true? Anyone have a definitive answer with a reputable source?

     

    www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA159471

     

    The linked document presents two mechanisms for Whop-Whop noises. One is high-speed impulsive noise that is created with trans-sonic bladetip speeds when the flow (not rotor blade) goes partially supersonic and creates a shockwave. This happens only at high forward flying speed. The other mechanism is blade-vortex interaction impulse noise which is caused by a blade hitting the wingtip vortex of the other blade.

     

    edit: Cool pictures of BVI noise: http://www.businessinsider.com/scientists-why-helicopters-are-so-loud-2014-2?IR=T

    Tacview 2.0, a glimpse into the future of flight analysis

    in DCS Modding

    Posted

    Having lift vector plane (defined by velocity vector and lift vector), 3/9-line plane (plane perpendicular to nose-vector) and wing plane (plane perpendicular to lift vector) visualized in HUD view would be useful. I think it would be best visualized by a lines drawn as circles around the view point, so that from the inside it looks like a continuous line. The lines would not be drawn over or under the HUD to not clutter it though. I have attached a picture to explain better what I mean. The plane in the center is just a representation of the viewpoint.

     

    attachment.php?attachmentid=112468&stc=1&d=1423053890

    412598274_TacviewHUDviewidea.png.42395ead57d4258b4d9617b360498e24.png

    Tacview 2.0, a glimpse into the future of flight analysis

    in DCS Modding

    Posted

    What zaelu is worried is that Tacview can't be used for one of it's most important functions which is review what actually happened in a MP fight on 104th server or the likes because you can't get the password afterwards for some reason. What's important is that realtime viewing is prevented and people get the recording reliably after they have finished the flight with as little effort as possible.

     

    I'm not sure if it's technically possible but the data could be encrypted while recording to prevent real time viewing. Decryption program or feature wouldn't work while the file is being written into but decrypting would be possible without passwords from the host.

    Tacview 1.3.1 is available!

    in DCS Modding

    Posted

    If vector A is from observer to target and vector B is "nose axis" of the target, targets aspect is the angle difference between vectors A and B if I'm not mistaken. This should result in the correct aspect angle also in 3d. Roll has no effect on aspect.

    New forum banner. And my new book.

    in Chit-Chat

    Posted

    Also, I just ordered a book called The Ace Factor: Air Combat and The Role of Situational Awareness. Is it any good?

     

    It's interesting but mostly it just proves the point that SA is very important. I don't think it has much that would make you better fighter pilot unless you really don't believe that SA matters. It's mostly about history (maybe about half is about WW1) and has some fascinating stories in it. In the end of the book it has some presumably Korean war era tactics articles which are useful but you can find better stuff in the internet.

    Deployment Mission 3, Stronghold, can't complete

    in DCS: Ka-50 Black Shark

    Posted

    That mission has (or at least used to have originally, I haven't checked the current version) some enemy infantry on a roof top and some years ago a bug was introduced that causes the infantry to teleport inside the building if they try to move (which they do when you start shooting at them). You can still kill them by shooting rockets at the building but it's very hard to know where to shoot. If this is the problem then only solution is to edit the mission and move the problematic guys down to ground or kill the ones on the rooftop first with a missile or something that gets them all with one blast.

    Rotor collision

    in DCS: Ka-50 Black Shark

    Posted

    a) Lower rotor affects the upper rotor presumably by sucking air downwards. How exactly the lower rotor affects the upper rotor is beyond me but NASA paper does say that it happens but lesser degree than the upper affecting the lower.

     

    b) Retreating side of the rotor disk has the same strength of down wash as the advancing side or the chopper would start to pitch up or down. This balancing act is done by the chopper pilot by pushing the cyclic forward (blade pitch increases at the retreating side and reduces at the advancing side) as speed increases.

     

    c) Precession occurs because the blade has tangential speed. When you apply a force to a moving abject, it doesn't start to move directly to the direction of the force but its trajectory shifts some degree to the direction of the force. In a spinning motion this causes the highest deviation from the neutral plane to occur somewhere after where the force was applied. If the rotor would be a rigid body it would be exactly 90 degrees. In a non rigid body like helicopter rotor the exact amount of degrees when the highest point occurs depends on multiple factors like mass of the blade, spin speed of the rotor, how the blade pitch changes with its rotation angle, etc. Basically "centrifugal" force tries to center the blade in the neutral plane like gravity in a pendulum while aerodynamic force resulting from blade pitch tries to move the blade away from the neutral plane.

    Rotor collision

    in DCS: Ka-50 Black Shark

    Posted

    Why would the no-lift area get dragged aft?

     

    And why would then the aft portion of the rotor disc - with the no-lift area - produce now more lift?

     

    The no-lift area gets larger, but predominantly on the side of the retreating blade - that is how I understand it. But I still can not see how/if that would add to the intersection risk.

     

    Basic thing is that force applied to the rotor causes movement about 90 degrees after the point where the force was applied. For example pulling cyclic back causes blade pitch to increase on the right side of the lower rotor and left side of the upper rotor ie. 90 degrees before front sector where the upwards tilt is desired. You can check this yourself in DCS BS. So whatever force is causing the lower rotor to tilt up the right side at high speed is applied at the aft portion of the disk.

     

    Upper rotor blows down on the lower rotor which needs to increase it's blade pitch in order to compensate for it. This flow is skewed by the apparent wind resulting from forward speed just like a column of smoke is skewed by a wind. Highest lift and highest downwards flow is at the tip of the blades as they move fastest. The closer the slow center flow gets to the outer rear edge of the lower rotor disk, the more lift is generated there because of less downwards flow from the upper rotor. This lift causes lower rotor disk to tilt up about 90 degrees after the point where the lifting force is applied (because of precession). As the lower rotor spins counter-clockwise this tilt up happens at the right side of the lower rotor disk.

    Rotor collision

    in DCS: Ka-50 Black Shark

    Posted

    ... yes? But what has that to do with the problem of intersecting rotor discs?

     

    Asymmetry of lift causes the chopper to pitch up when speed increases which you counter by pushing cyclic forward.

     

    Rotor collision is caused by lack of downwards airflow at the rear of the lower rotor. Center of the rotor doesn't push air down as there's no blades and the inner portion of the blades move slowly. This slow speed flow area get's dragged aft when chopper increases it's speed increasing the lift at the rear sector of the rotor disk much more than elsewhere. This extra lift at the rear causes the right side of the lower rotordisk to raise when speed increases (remember the precession effect).

    Low Rider

    in DCS: Ka-50 Black Shark

    Posted

    Jesus Christ, how much practice did it take to fly this course?

     

    Mind posting the mission somewhere so others can try as well? Looks like a really fun challange :pilotfly:

    In my Sense Of Speed video with A-10C someone put up a comment like "It would take 100 crashes for me to do the same" or something like that but that's about what it took for me to do that video. I think I managed this Ka-50 version with quite a bit less crashing because of lots of practice with A-10 under my belt but bottom line is you got to put in the hours to do something out of the ordinary. Low altitude flying at high speed requires good sense of where the aircraft is going (TVV helps with this a lot but doesn't make the skill redundant), ability to intuitively anticipate the aircrafts reactions to control inputs and smooth flying technique. Sensing the flight path and smooth control technique are universal skills that transfer between plane types and help with every type of flying.

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