Aces High Bulletin Board
Help and Support Forums => Aces High Bug Reports => Topic started by: Krusty on May 06, 2005, 07:14:32 PM
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I heard about this a while back, but I thought it was fixed. Guess not!
Rockets fly along the path of the aircraft, NOT the direction you are pointing. Took up the 190F8 to test out the panzerblitz rockets... I was lined up, but drifted to the side, way off target, so Iadjusted with rudder, the pipper was dead on, fired off 2 rockets, and Lo, Behold! They landed where my sight was when I found it was drifting. That is to say I had adjusted with rudder but the rockets flew along my PATH, not along my AIM.
That's a half-assed way of having rockets fly, eh? Bullets adjust to rudder input, bombs and rockest should as well, or there's no point. Nobody is ever going to have 100% no-drift aim for rockets every time. Rudder input is necessary.
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That's a half-assed way of having rockets fly, eh? Bullets adjust to rudder input, bombs and rockest should as well, or there's no point. Nobody is ever going to have 100% no-drift aim for rockets every time. Rudder input is necessary.
Real physics is anoying :) I am not an expert on the topic, but I would bet an iron bomb is going to fall in the direction it is moving, not the direction it's pointed.
Rockets have fins like an arrow, so I would also think they would want to go the direction they are moving (the direction of the plane, not the direction they are pointed).
Bullets have no fins, and leave the barrell at a high velocity, they should be able to be controled more by Yaw.
I think this is the way it works in the game.
Gunner
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The rockets are lined up with the fuselage of the craft. they are parallel, let's say. The wings are attached to the fuselage and the rocket rails are attached to the wings. The rockets launch off these rails.
You yaw and fire.. well your plane turns, thus your wings and thus the rocket rails, THUS THE ROCKETS turn! Tada! The rockets are now facing a new direction. So the fins should HELP them fly in that direction, instead of skidding forward.
But the way I heard about the bug, if you're in a flat spin and fire off your rockets they will shoot straight down (the direction you're falling) regardless of the way you are aiming.
Like I said, bass ackwards ;)
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Say your going 300 mph N, you yaw NNW, when the rocket comes off the rail it is going 300 mph N but pointing NNW. The rocket has fixed fins and will point back to the N and will accelerate N.
There may be a bug there, but it seems right to me.
Gunner
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The rocket is not released. It is propelled really fast at a forward rate. A rate determined by the angle it is pointing and stabilized by those fins. A bomb would skid forward yes. But the rockets would auto correct. The rails, the rocket motor, and the fins, all act to make the rocket follow the nose of the plane.
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Would they not "Weathervane" and attempt to align with the relative wind? i.e. with the direction of travel. At least until the rocket motor overcomes the speed of the aircraft in an off axis shot. I would expect it to not hit where you think it should.
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Originally posted by Lye-El
Would they not "Weathervane" and attempt to align with the relative wind? i.e. with the direction of travel. At least until the rocket motor overcomes the speed of the aircraft in an off axis shot. I would expect it to not hit where you think it should.
Yes you correct, they will weathervane untul the motor overcomes the drag of the forward motion "wind". This will cause your aim to be off if you are skidding when you fire.
Krusty, most rockets/missles (now I don't know if this is modeled in AH) are dropped a fraction of a second prior to the motor igniting. I believe this is to prevent the rocket motor from setting the plane on fire. This is why they will **** towards the forward motion of the aircraft. Even the smallest amount of deflaction at the launch point will translate into a large deviation from the intented target depending on range to target.
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Correction, most MISSILES are dropped, and those are modern things like AIM-5s and so forth. Most ROCKETS (air to ground stuff) are launched off the rails (like a model rocket kits has loops that slide onto the launch rail), and they are literally slotted onto those rails when put on by the ord crew. This would negate most sliding.
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Modern rockets are guided and when they are dropped they stear to their target. The dumb rockets used here are un-guided and have fixed fins.
The sliding comes from the initial speed and direction. When you move your rudder, the nose yaws away from your direction of travel. The rocket is also starting out with that initial speed and slip plus it gets vectored for an instant in the direction it is pointing until it leaves the rail. When it reaches the end of the rail, it will point back to the direction it is moving. I agree that the thrust of the rocket will change it course, but it will not continue to travel the direction it's pointed. The result is when you move the rudder, you don't know where the rockets are going to go. :)
To make a good rocket hit, you need to have your aircraft diving in a clean dive pointing at the target when you release the rockets. A zero G drop is best to get consistant hits. The same goes for bombs. It isn't easy.
The good thing... I am sure HTC will see this on Monday and if there is a problem, they will fix it. I can never hit anything with rockets anyway. :D
Gunner
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I find it more likely that a rocket launching straight off rails and with stabilizing fins and a powerful rocket motor propelling it along the path of those rails and fins would overcome any sliding momentum almost immediately (we ARE talking about a light weight object with very little surface area, what little inertia it has would be overcome quickly).
However, don't confuse accurate modeling with a flaw in the way AH fires rockets. That doesn't explain rockets firing downward when you're in a flat spin. I'm going to see if I can recreate this event sometime today (when I get the chance)... I think P38 with its infamous spin would be a good test bed.
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E=1/2MV(squared)
The energy of a moving object is one half the mass times the square of the speed. As the speed increases, the kenetic energy in the rocket, even if it is relatively light, comes from the speed. From the energy formula, I have a feeling at high speeds, the kenetic energy of the rocket is is going to have a huge effect on the direction it go.
The same thing may happen if your in a flat spin falling at a high rate of speed. If you test this, see if you can get in flat spin from high alt dropping at a high speed. I would guess you may be able to get the rockets to drop down, if the physics are right :)
Gunner
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No. you're thinking they're unpowered. The rocket motor itself has the greatest impact on the flight of the rocket. Most release speeds are going to be 250-(max)300. The rocket is going at least 500 or more when fired. You can NOT tell me with any seriousness that a plane falling in a flat spin (yawing but upright and falling straight down) is going to fire rockets off rails with stabilizer fins and have them FLY DOWN? *cough*BS*cough*.
The rockets would fly outward in a circular pattern depending where the nose was pointed at the time they were fired.
Puh-leaze
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Originally posted by Krusty
No. you're thinking they're unpowered. The rocket motor itself has the greatest impact on the flight of the rocket. Most release speeds are going to be 250-(max)300. The rocket is going at least 500 or more when fired. ...
Puh-leaze
No, I am thinking the rocket motors of WW2 did not accelerate the rockets from 250MPH to over 500MPH in the lenght of the rail (maybe 4 feet) But I am not a rocket scientist, and I did not stay at a Holiday Inn last night .
I think the force of the rocket motor will be small compared the the kenetic energy of the rocket when it leaves the rail, causing it to turn the direction of the kenetic energy of the rocket (the direction it is moving). The rocket continues to accelerate, but not in the direction it was pointing when released. I don't have the specs on the rocket, so I can't prove this. Even if I did, for some reason, I don't think you would believe me anyway :)
I am thinking the problem is, in real life, the rockets would most likely hang up on the rail when fired in extreme conditions.
Gunner
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No, if the rocket motor were so weak that the fins automatically dug into the wind and turned it to the direction of the skewing aircraft, then the thing would drop to the ground. Rocket motors burn fast and die quickly. Anybody that's seen a model rocket in flight knows this. They accelerate within a couple of seconds. They are more powerful than you think. The entire tube of the rocket is the motor (in real life, not model rockets) and the rocket fuel housing. All of that is propelling it forward at high acceleration.
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As a side tangent, and this is in no way proof, but is suggestive, every other game I've ever played made air-to-ground rockets fire at the direction the nose was pointing (whether rail-mounted as in WW2, or pod/tube mounted as in jet era)
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From SIMHQ author Andy Bush:
http://www.simhq.com/simhq3/sims/air_combat/atgbasicsp3/atg3.shtml
Delivery Considerations Unique To Forward Firing Ordnance
We often think of these weapons as ‘point and shoot’ types. This ain’t necessarily so, as we will now see!!
The first consideration is a phenomenon known as ‘tip off.' Tip off applies only to rockets and is the result of the misalignment of the rocket launch line and the aircraft relative wind. Think of this misalignment as the angle of attack of the rocket when it comes out of the launcher. If the rocket is not pointed directly into the relative wind at launch, it will attempt to align itself with that wind as it is launched. This will happen because of the natural tendency of the rocket to streamline itself with the air flow of the relative wind. For this reason, fighter launcher rails are often designed to line up with the relative wind. This figure of an F-4 shows this.
Rockets are meant to be fired at or near one G conditions. Any G load (positive or negative) more than this one G firing condition will change the aircraft angle of attack, resulting in a rocket flight path that bends towards the relative wind. This ‘bending’ or change in the rocket flight path is the ‘tip off.' As the G load increases, so does the magnitude of the tip off. Here is a picture of tip off.
The only way to avoid tip off is to make very sure you are at approximately one G when firing your rockets. One final point...yawing your aircraft will produce a lateral or ‘sideways’ tip off. Do not use the rudder to correct your aim when shooting rockets!
The second consideration has to do with firing the gun while in a yaw (rudder deflected). While tip off is not a significant factor when firing the gun, the application of rudder to correct your aim point is. The gun is a wonderful thing but it is not a laser beam! The gun projectile still has to obey the laws of physics. One of these laws has to do with the resultant velocity vector of the projectile when it is fired.
The resultant velocity vector is a combination of the vector of the projectile and the velocity vector of the aircraft. The next figure shows the effect on the resultant bullet trajectory when the aircraft is yawed:
(http://www.simhq.com/simhq3/sims/air_combat/atgbasicsp3/fig14.jpg)
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Guess that settles it!
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Yup! That settles it! AH2 is bugged!
Rockets do not fly on tangent. They fly directly along direction of flight, not halfway between.
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Clifra, thanks! Good find, Andy Bush writes some good stuff.
But "Krusty Physics" sounds much easier :)
Gunner
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Originally posted by Krusty
Yup! That settles it! AH2 is bugged!
"In AH2 Rockets do not fly on tangent. They fly directly along direction of flight, not halfway between."
Fixed to avoid confusion. I wasn't ignoring what was posted. I was saying that it brings to light how bugged AH2 is.
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Originally posted by Krusty
Fixed to avoid confusion. I wasn't ignoring what was posted. I was saying that it brings to light how bugged AH2 is.
In reference to the picture above. If rockets are flying along the green line as apposed to the blue line then yes, it is a bug. AH is not taking into consideration the relative wind "tip off". This would mean that the rockets are firing along the velocity vector. Which would be incorrect.
Whether this is a bug or not is irrelevent in the firing of rockets as the crux of the article states that you should be in a straight flight path at 1G, no slip, when firing rockets.
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This *is* the bugs forum. I think it's very relevant, and was the reason I posted in the first place.
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Krusty:
You said that some one told you they saw rockets go straight down when in a flat spin, right? Then, simple enough:
1) Go offline
2) Roll film
3) Take up a plane with rockets loaded
4) Take said plane up and get into a flat spin or a tail stall (coming down backwards).
5) Fire rockects
6) Crash
7) Stop filming
8) Review film and send it to HT if it validates your theory...otherwise, fahgedabowddit :D