Am I missing something? - Illumination Rockets

[DTWD]

Afternoon all,

 

I have recently started getting back in BS after about an 9 month hiatus (I got lazy and it was too much effort plugging everything in, setting it up etc). I have installed the latest patch and over the last few weekends I have been testing out the new kit, setting up my joysticks again (new profiles) and learning to land/fly/shoot again. However I got a bit lost on the weekend.

 

How are you supposed to use the illumination rockets?

 

I loaded out fully with them (I was going to do some night shooting with the gun) and proceeded to my target zone at the dead of night. I got roughly in position (using the NV goggles) and let rip a salvo of illumination rockets to see them (or not as the case me be) disapear in the night never to be seen again.

 

Puzzled by the lack of anything happening I let off a few emergency and signaling flares all of which worked (i.e. I could see them) and then flew a little lower and over land this time. I was originally fireing the rockets over a bay and assumed maybe they plopped into the sea and not hit the ground. So over land this time I let off another salvo...nadda. So lower I go and skimming the tree tops (more by crap flying than judgment) I off my last salvo and again nothing.

 

I see the rockets leave the tubes and I can make out some sort of smoke trail but they just disapear without "illuminating" anything.

 

Am I using them correctly? If not how am I supposed to use them, and if I am, what exactly are they supposed to do?

 

When I got back to the edit screen I checked I had attatched illumination and NOT smoke, and I had.

 

Any ideas?

[159th_Viper]

Puzzled by the lack of anything happening I let off a few emergency and signaling flares all of which worked (i.e. I could see them) and then flew a little lower and over land this time. I was originally fireing the rockets over a bay and assumed maybe they plopped into the sea and not hit the ground. So over land this time I let off another salvo...nadda. So lower I go and skimming the tree tops (more by crap flying than judgment) I off my last salvo and again nothing.

 

 

They do not work over the Sea. At what Altitude did you deploy them over land?

[JG14_Smil]

try raising the nose of the helo when you fire them for a higher arc(?).

[Spider76]

Readme patch 1.01 - HowTo:

employ illumination rockets using a pitch-up maneuver. 10 - 45 degrees up into the sky.

 

S-8OM – illumination rocket. Once fired, the rocket flies a ballistic trajectory. After 17 seconds, the nose section separates, a drag chute opens and the illumination flare begins to descend at a rate of 8.2 m/s. The flare burns for 35 seconds. The S-8O (OM) illumination rockets are designed to increase the effectiveness of aviation and other battlefield forces in nighttime conditions by providing artificial illumination of specific areas of the terrain.

 

AI helicopters are now able to employ illumination rockets using a pitch-up maneuver.

Edited October 5, 2009 by Spider76

[159th_Viper]

To Clarify: Dependant on Attitude at Launch, you need to be at least 1000mAGL, preferably Higher.

[DTWD]

Thanks for the responses.

 

I am not sure if I was 1000M's AGL that's for sure, I didn't look, but I could have been. Regardless though I was firing them like I normally fire rockets, into the ground. I was under the impression they were like the smoke rockets and basically made little (but bright) fires. They certainly wouldn't have got 17 seconds flight time.

 

Is there a way to shorten the fuse?

 

And where do I find this readme? I was wondering where something like that would be.

 

I will give your advice next weekend and see what happens.

 

Does anyone know of any screen shots around with these flares in operation?

[159th_Viper]

 

 

In-Cockpit: 2 Rocket Salvo

 

Edited October 5, 2009 by 159th_Viper
Pic added

[DTWD]

Yeah...I saw nothing like that.

 

They would show up in NV wouldn't they? I mean there isn't a bug in that respect?

[159th_Viper]

Yeah...I saw nothing like that.....

 

 

 

With NVG:

 

[DTWD]

Well you wouldn't miss that...cheers very much.

[Waldo_II]

I remember experimenting with them. They were horrible. They go an incredible distance before illuminating, they don't work for very long, they didn't illuminate a large enough area, they were difficult to aim, and I always had to yank the nose up before firing. They don't fit the role of attack helicopters because in order to use the effectively you have to be high up.

 

 

Assuming the missile drops, during flight, at a rate of 9.81m/s^2, and drops at the rate of 8.2m/s, flies for 17 seconds and illuminates for 35 seconds, the minimum height for maximum employment of a single missile is 8.2(17)+9.81(17*17)=3,122, meaning you have to be 3,122 meters high to get the full effect of illumination, if you shoot straight at zero degrees.

 

The formula for calculating at what angle you should shoot, when given the speed of the rockets and the desired distance, use this, where X is the angle of launch, and the function of X is the distance.

 

f(x)=[(x/90)(speedofS-8]8)8) * ( {[ (90-x)/90 ][ speedofS-8 ] + current altitude} / 9.81)

 

It helps to have a fancy graphing calculator.

Edited October 5, 2009 by Waldo_II

[sobek]

Assuming the missile drops, during flight, at a rate of 9.81m/s^2, and drops at the rate of 8.2m/s, flies for 17 seconds and illuminates for 35 seconds, the minimum height for maximum employment of a single missile is 8.2(17)+9.81(17*17)=3,122, meaning you have to be 3,122 meters high to get the full effect of illumination, if you shoot straight at zero degrees.

 

IMHO you err in a few points with this calculation. First, the missile does not start out with a drop rate of 8.2m/s, this is the drop rate when the chute is deployed and it is illuminating, so you would have to multiply the 8.2 m/s with 35 seconds of illumination. Second, if i'm not mistaken, the missile will not accellerate along it's z axis with 9,81 m/s^2 as long as the motor is burning (and probably also not after it has stopped, the point being that missiles have flight surfaces). One would have to know the trajectory of the specific missile to be able to correctly approximate how much it drops during the 17 seconds of flight.

[AlphaOneSix]

If you fire the illumination rockets from ground level at a nose high angle of 15 degrees, the rockets will travel 7km (6.76km over the ground) and burst at an altitude of 1811 meters. Of course, this assumes that the rockets will travel in a straight line, which they won't, but 15 degrees is still enough to get the rockets to the proper altitude of 500-1000 meters.

 

Dropping at 8.3 meters per second (I'm pretty sure it's 8.3 and not 8.2) and burning for 35 seconds, the flare will be burning for 290 meters, so even 500 meters is a good minimum altitude for the flares (although 1000 meters should give better coverage, but I'm not sure exactly how that's modeled in the game).

[Waldo_II]

IMHO you err in a few points with this calculation. First, the missile does not start out with a drop rate of 8.2m/s, this is the drop rate when the chute is deployed and it is illuminating, so you would have to multiply the 8.2 m/s with 35 seconds of illumination. Second, if i'm not mistaken, the missile will not accellerate along it's z axis with 9,81 m/s^2 as long as the motor is burning (and probably also not after it has stopped, the point being that missiles have flight surfaces). One would have to know the trajectory of the specific missile to be able to correctly approximate how much it drops during the 17 seconds of flight.

 

You are very correct in that 8.2m/s should be multiplied by 35, a typo on my part.

 

You are also correct in that 9.81 m/s^2 is probably inaccurate. The fin stabilization would definitely flatten the flight path. I haven't the knowledge to calculate an accurate trajectory, nor the proper input in terms of dimensions of the fins, so I decided to leave it at 9.81.

The motor burning has nothing to do with the rate of fall in the quoted scenario, only the air resistance/lift generated. Lift is virtually zero because the missile loaders have no control over the orientation of the rocket when fired, so lift/drag forces are equal on all axis. Since the motor is only pushing the rocket forward, not affecting the vertical axis, it does not change the rate of fall. If the rocket were fired upward at an angle, such as in scenarios in which my second equation would be useful, then that certainly can have an effect, although the difference in real life versus my model would be minute. My model accounts for linear, constant velocity ( [ (90-x)/90 ][ speedofS-8 ], but not for nonlinear effects of acceleration and nonlinear flow of fuel into the engine.

[AlphaOneSix]

If the rocket were fired upward at an angle

 

The extended hard cover manual available for purchase states that the illumination rockets should be fired at an angle of 15 to 20 degrees nose up. They are not intended to be fired straight ahead. Any calculation should assume that the rockets are fired at an angle of 15 to 20 degrees.

[Jrod]

They don't fit the role of attack helicopters because in order to use the effectively you have to be high up.

 

 

 

The US uses them all the time in OIF & OEF off the AH-64D platform. They work very well. :thumbup: