Some questions about laser rangefinder

hi，

i'm puzzle by how does the KA50's Laser rangfinder work.

it's said that:laser rangefinder has limitations: 5 series with intervals of 30 minutes; 16 cycles of 10 seconds with intervals of 5 seconds in each serie.

questions:

1."5 series with intervals of 30 minutes",is that means the laser rangefinder on KA50 can just work 5 times with 5 series all had been used.

2.what will happen in real life after the 5 series had been used? replacement?refule(if it powered by chimerical materials)? or charge?

Thanks for any help. :smilewink:

Prichal

 

OKB: UOMZ

 

Chief Designer: I P Belezertsev

 

Laser rangefinder/designator of the Su-25T (and Ka-50) Shkval system. Production launched in 1988.

 

Prichal operates at 1.064 micron wavelength. It uses a 5Hz pulse repetition rate in rangefinding and 10-25Hz in illumination mode. It has greater range than the older Klen-PS and a narrower beam of 1.5 angular minutes. Rangefinding error was no more than ±5m, maximum range 10km, weight was 46kg and maximum power consumption 4.8kW.

 

The Prichal laser rangefinder and designator requires a cooling cycle prior to operation in the ratio of 0.8 to 1 times the time it was previously activated.

 

The cooling cycle can be over ridden if necessary but will decrease the life of the laser.

Laser lifespan = 5 series (30 minute minimum interval)

Series = 16 cycles (5 seconds minimum interval)

Cycle = 10 seconds continuous illumination

So to even get 1 series you have to fire about 16 Vikhr missiles as these are the only uses that give long enough duration to really matter. When you fire the laser rangefinder you get 3.0 second continuous emission cycles, one per rangefinding command.

2.what will happen in real life after the 5 series had been used? replacement?refule(if it powered by chimerical materials)? or charge?

Like frederf mentioned, it's just a guideline. The laser life isn't limited by an "ammo belt" of chemical fuel or anything such - the problem is heat.

As you can see in the bit quoted, it can consume up to 4.8kW, which is a lot of heat. The heating elements I use at home to help against the -30 degrees celcius we have outside right now doesn't even come close to that. So for this reason it is very important to allow that heat to dissipate to prevent components warping or frying due to heat stress.

Obviously though, sometimes you will find yourself in a situation where you have to disobey those guidelines in order to defeat a threat either to yourself, your wingman, or the ground forces you are tasked to protect. However, I would definitely recommend some caution even in a really heated (geddit? :P) engagement, since those tend to be the longer ones and you can lose more lives on your laser getting fried than taking those 5 second cool-down periods between each lasing.

Laser lifespan = 5 series (30 minute minimum interval)

Series = 16 cycles (5 seconds minimum interval)

Cycle = 10 seconds continuous illumination

Again for dummys like me:

I can continuous illuminate for 10 seconds.

After the 10 seconds I have to cool it down for 5 seconds.

This I can do 16 times. (shoot all Vikhr)

After this 16 times I have to cool down for 30 minutes (because of end of the 1st series).

This all I can do 5 times.

So if I cool the laser down for 5 seconds after I illuminate for 10 seconds, cool down the laser for 30min after I shot all 16 Vikhr, and do my rearm max 5 times the laser should be ok till this time?

Right?

Question:

What's with a range measuring? This takes half a second and I have to cool down the laser for 8 seconds (countdown in the HUD)

What happens if I illuminate a target in 10Km range? The laser have to illuminate it more than 10 seconds because of the long way the Vikhr have to fly...

These cycles, intervals, series are really only guidelines for increasing laser life. I believe that the laser is generally inspected, serviced, or replaced after a certain amount of use.

 

 

Laser lifespan = 5 series (30 minute minimum interval)

Series = 16 cycles (5 seconds minimum interval)

Cycle = 10 seconds continuous illumination

 

 

So to even get 1 series you have to fire about 16 Vikhr missiles as these are the only uses that give long enough duration to really matter. When you fire the laser rangefinder you get 3.0 second continuous emission cycles, one per rangefinding command.

Like frederf mentioned, it's just a guideline. The laser life isn't limited by an "ammo belt" of chemical fuel or anything such - the problem is heat.

 

As you can see in the bit quoted, it can consume up to 4.8kW, which is a lot of heat. The heating elements I use at home to help against the -30 degrees celcius we have outside right now doesn't even come close to that. So for this reason it is very important to allow that heat to dissipate to prevent components warping or frying due to heat stress.

 

Obviously though, sometimes you will find yourself in a situation where you have to disobey those guidelines in order to defeat a threat either to yourself, your wingman, or the ground forces you are tasked to protect. However, I would definitely recommend some caution even in a really heated (geddit? :P) engagement, since those tend to be the longer ones and you can lose more lives on your laser getting fried than taking those 5 second cool-down periods between each lasing.

Thanks a lot!:smilewink:

Black Shark is a really great flight simulator! :thumbup:

What happens if I illuminate a target in 10Km range? The laser have to illuminate it more than 10 seconds because of the long way the Vikhr have to fly...

The laser shuts down and your Vikhr loses guidance. ;)

Question:

What's with a range measuring? This takes half a second and I have to cool down the laser for 8 seconds (countdown in the HUD)

If I understand the manual right, the laser is actually active as long as there is a count down timer on the hud and only when the text "ПАУЗА" is displayed is it in cool down mode (which is the same as not being on)

Thus it is range finding for 8 seconds, and not 0.5 seconds + 7.5 cool down.

same thing when firing vikhrs, those last 6 seconds that gets added isnt a cool down period, the laser is still active in case it takes longer for the vikhr to reach the target than the computer first had in mind, the laser will only start to cool down once the timer runs out (or, if "ПАУЗА" is displayed).

If I understand the manual right, the laser is actually active as long as there is a count down timer on the hud and only when the text "ПАУЗА" is displayed is it in cool down mode (which is the same as not being on)

 

Thus it is range finding for 8 seconds, and not 0.5 seconds + 7.5 cool down.

 

same thing when firing vikhrs, those last 6 seconds that gets added isnt a cool down period, the laser is still active in case it takes longer for the vikhr to reach the target than the computer first had in mind, the laser will only start to cool down once the timer runs out (or, if "ПАУЗА" is displayed).

Hm... are you sure? Can anybody confirm that?

If I consider the HUD countdown my laser will never burn out.

I spot a target by using the Shkval with laser OFF.

I turn on the laser and make a range measuting.

The countdown in the HUD is decreasing.

If the countdown is "0" I will shot the Vikhr.

The Vikhr hit the target after ca. 6-8 sec and the countdown decreases from "6" to "0".

I should off the laser and surch for the next target.

I turn it on and make a measuring again....

If I do it like this my laser will not burn out!

If your posting is correct my laser is ON for more than 20 sec without cool down for each shot.

Hm... are you sure? Can anybody confirm that?

If I consider the HUD countdown my laser will never burn out.

I spot a target by using the Shkval with laser OFF.

I turn on the laser and make a range measuting.

The countdown in the HUD is decreasing.

If the countdown is "0" I will shot the Vikhr.

The Vikhr hit the target after ca. 6-8 sec and the countdown decreases from "6" to "0".

I should off the laser and surch for the next target.

I turn it on and make a measuring again....

 

If I do it like this my laser will not burn out!

If your posting is correct my laser is ON for more than 20 sec without cool down for each shot.

I agree.. Check out the Producers notes... Specifically 5:30.

When the “АВТ ЗАХВ”

button is pressed, the laser rangefinder is turned on for approximately three seconds.

The laser-range finder of the targeting system measures slant range to target and is directed toward the same point as the line of sight of the electro-optical targeting system.

If the “АС-ПМ” (Auto-Tracking – Gun sight) switch [P] on the Targeting Mode Control Panel is set to “АС” (Auto-Tracking) and the “ППУ” (Moving canon – automatic weapons mode) mode is selected, the laser range-finder is activated with the first depression of the “АВТ ЗАХВ” (Lock) button and remains active for three seconds.

What's with a range measuring? This takes half a second

If I understand the manual right, the laser is actually active as long as there is a count down timer on the hud

Be aware that rangefinding takes much more power than missile guidance. The rangefinding beam has to travel all the way to the target (which is painted to not reflect), bounce off a funny shape, and come all the way back to be detected by equipment small enough to fly in a helicopter's nose. You need a very strong laser for this. Vikhr guidance shines on the back of the missile, one way trip, sensitive receivers that want to see the laser energy from the Ka-50.

3 seconds of laser rangefinder = MUCH POWER, MUCH HEAT

8+ seconds of laser Vikhr guidance = LESS (1%?) POWER, LESS HEAT

Just because Vikhr takes a long time doesn't mean it is the worst case. It is longer but low power. The fastest way to burn the laser is to use rangefinding.

So it isn't so bad to laser rangefind and then shoot a Vikhr before the countdown is all the way down. The timer is supposed to separate high-power rangefinds apart but the cooling needed between a rangefind and a Vikhr guidance is less than the countdown shows.

Thank you Frederf for answering that complex.

But I don't understand the talking about series, cycles and times if the laser is working completely different in this two modes (rangemeasuring and guidance).

It is still a mysterium how long the laser is working or not and how often I'm able to use it.

Laser lifespan = 5 series (30 minute minimum interval)

Series = 16 cycles (5 seconds minimum interval)

Cycle = 10 seconds continuous illumination

Is this for rangefinding or for guidance? Or both? Or what???

Sorry, I'm confused now...

Is it correct at all what I wrote in the upper posting?

I can continuous illuminate for 10 seconds.

After the 10 seconds I have to cool it down for 5 seconds.

This I can do 16 times. (shoot all Vikhr)

After this 16 times I have to cool down for 30 minutes (because of end of the 1st series).

This all I can do 5 times.

Yeah, sorry for skipping that answer. You have the correct idea there but I still want to stress that these definitions of cycles and series and whatnot are purely artificial to make it easier and organized for the ground crews to keep tabs on laser wear and tear. You shouldn't think they are too exact or take them too seriously.

I believe that the guidelines are more for the rangefinding mode but obviously 10 seconds is Vikhr guidance mode territory. It's like some mashed together hybrid idea that sacrifices total applicability to make it easier to remember. Otherwise the pilot would have to remember the laser wear of 1 rangefinding followed by 2 Vikhr launches differently than 2 rangefindings followed by 1 Vikhr launch. With a "hybrid" understanding those both might be "3 cycle" uses which makes it easier to understand. For all I know a 10-second low-power Vikhr guide and a 3-second high-power laser rangefinding might be so close to each other in terms of laser heat/wear that calling them both "cycles" might be perfectly justified.

You are definitely a good pilot in that you want to know how to treat your equipment well in order for it to keep working. To be completely honest, I have a suspicion that "laser burnout" is not modeled in DCS or that it is not modeled in a sensible way. There was a rash of incidents among forum users where the laser ceased to function (especially related to rearming) but I believe it was concluded that the reason for the failure was not "working as intended laser burnout" but actually some sort of bug.

I don't know of any forum user that can say with certainty that the laser is even possible to break with use in DCS:BS. Even if it isn't possible to break it in the sim but you want to be a good pilot and role play how the real-life laser would react we don't have perfect information about that either. The cycle/series blurb in the manual is probably a good, safe starting point. Considering that we get a fresh Ka-50 out of the plastic wrap every time we fly, being kind to the airframe/crewcheif for long term maintenance concerns is up to the pilot and often areas where we don't have a lot of information for.

Be aware that rangefinding takes much more power than missile guidance. The rangefinding beam has to travel all the way to the target (which is painted to not reflect), bounce off a funny shape, and come all the way back to be detected by equipment small enough to fly in a helicopter's nose. You need a very strong laser for this. Vikhr guidance shines on the back of the missile, one way trip, sensitive receivers that want to see the laser energy from the Ka-50.

Aye, amongst other things it's an example of the magic of the inverse square law. Very similar also to why RWR's will spot an emitter at longer ranges than the radar itself will spot the target that has the RWR - the RWR needs to only detect energy that has gone one way (with strength diminished by the inverse square law), but the radar itself has to detect whatever echo is sent back and is yet again affected by that law - becoming inverse cube. Laser rangefinding suffers from similar problems (though potentially not quite as severe since it's width is just a minute, but I never checked the typical width of modern radar beams, so the comparison might be off - also added benefit in lack of sidelobes but that's derail) wherefore more pure wattage is required.

Also, lets remember that this is not only 4.8kW - it's 4.8kW being generated by a compact piece of electronics. A normal desktop processor only has a TDP of 60-100 watt, yet what happens if you start that up without a cooling heatsink/fan assembly attached?

It would be interesting to know some more details about the specific cooling system utilized by the laser tho. Anyone know?

To be completely honest, I have a suspicion that "laser burnout" is not modeled in DCS or that it is not modeled in a sensible way. There was a rash of incidents among forum users where the laser ceased to function (especially related to rearming) but I believe it was concluded that the reason for the failure was not "working as intended laser burnout" but actually some sort of bug.

It is modeled. Whether it's modeled "sensibly" I don't know, obviously, since that would require viewing the code for that AND having complete data from the real unit to compare with, and I can't do that. :( However, ED has said data so aside from the possibility of any additional bugs (or faulty documentation received, compare with the HH data which turned out to be incorrect and where they had corrected documentation passed to them from Kamov in time for 1.0.1) it should be correctly modeled - as near as any model can predict such behaviour.

However, yes, there was a bug in this area that was particularly hard to track down since it's symptoms superficially were similar to intended behaviour (that is, the intended behaviour of simulating laser burnout). This bug was fixed in 1.0.1, afaik.

I don't know of any forum user that can say with certainty that the laser is even possible to break with use in DCS:BS.

*raises hand*

There is a thread somewhere in the Problems and Bugs section where this was discussed, back in vanilla when the mentioned bug was being tracked down.

I don't know of any forum user that can say with certainty that the laser is even possible to break with use in DCS:BS. Even if it isn't possible to break it in the sim but you want to be a good pilot and role play how the real-life laser would react we don't have perfect information about that either.

Keep in mind I fly mostly MP online.

Mine breaks down regularly at ~2.5 flights. Thats about I've spent 24 Vikhrs on the two first flights and some 3-8 on the third flight.

So ~30 launches.

Ranging must have happened so the targets some ~30-40 times depending on what weapons I deployed in all the flights. (Quite alot of ranging with guns, and most often spending the full rack of rockets).

So yes, it does break down. I'm not close to 80 (max number of cycles), but I abuse the laser (not enough cool-down) when I have to, rather that or risk loosing the bird.

On rare ocasions I'm able to fly 3 full flights and spend 3 racks of Vikhr.

This may happen due to me skipping the ranging on multiple targets in the same zone - snapshot and manual steering.

Ah, I only followed that laser bug/not-bug issue to a point and not to its conclusion. I had only experienced laser failure pre-1.01 (I believe the "bug" version of the failure) and never since 1.01. I would think that belief that the laser to be invincible would encourage me to use the laser to destruction and since I hadn't done so in many hours of flying that it was not possible. Perhaps I am just more cautious or gentle with the laser than I knew.

I'm going to load up a SP flight and just range as fast as I can until laser destruction. I should be able to break the laser without firing a single Vikhr.

With a "hybrid" understanding those both might be "3 cycle" uses which makes it easier to understand. For all I know a 10-second low-power Vikhr guide and a 3-second high-power laser rangefinding might be so close to each other in terms of laser heat/wear that calling them both "cycles" might be perfectly justified.

This makes sense to me.... maybe a ED-developer can canfirm that? :worthy:

So. After each rangemeasuring and vikhr-launch I have to cool down the laser for 5 seconds.

After 16 rangemeasurings or vikhr-launches I have to cool it down for 30 minutes.

This all I can do 5 times.

Right?

Sorry for reopen this topic again, but I have two questions:

First question:

What is your source for the information that the laser is active for 3 seconds if you make a rangemeasuring?

The first time I make a rangemeasuring the countdown begins at "3".

The second time and all times after, the countdown begins at "8".

The symbol "ТА-ИД" is active for the whole time the countdown is counting.

Isn't it right that this symbol means "laser is active"?

So the laser is active for 8 seconds if you make a rangemeasuring.

... but why?

The range will be displayed immediatly after I push the button!

For my technical understanding it is not necessary to get the laser active for that long time.

Second question:

I tried to find a way to by-pass the rangemeasuring.

- I searching for enemys with the shkval, laser is OFF.

- I found a enemy and adjust the target-box at the enemy

- I switched the laser to STANDBY and locked the target (TA)

-> Laser is active for -?- time to do the rangemeasuring, countdown will be displayed

- After the countdown I shoot the Vikhr.

-> Laser is active for time till impact plus 6 seconds.

- Directly after impact I unlock the old target, moving the target-box to the next taget and lock it (TA) within this 6 seconds the laser is still active.

Is there a rangemeasuring too for the second target????

EDIT:

OK, I found the answer to the first question in the manual.

If you simply lock the terrain to adjust the shkval to the point in the terrain, the rangemeasuring is active for 3 seconds!

If you lock a target (activate the automatic target tracing TA) the rangemeasuring is active for 8 seconds!

I think because it is possible that the target is moving and the range is changeing.

In my point of view this 8 second-measuring is one cycle.

So you have to wait for 5 seconds after this 8 seconds before you start the vikhr.

Now I simply need a answer to my second question....

It would be interesting to know some more details about the specific cooling system utilized by the laser tho. Anyone know?

I was an Aviation Environmental Systems Technician for a while in the military. There are a lot of different systems used for cooling weapons and equipment, but the two most widely used are Air Cycle Turbines (ram air) and Chemical Condenser (liquid chemical).

The liquid chemical system is similar to what you'd see in a car, but the military uses chemicals that make freon seem drinkable in your morning coffee. In some heat exchange systems they use liquid nitrogen when necessary, but that is super inefficient and dangerous due to the high expansion rate (800:1) of a chemical that is -321F. Liquid nitrogen is just super compressed gas. It's much more efficient to compress a gas or liquid in a closed system where it doesn't have to bleed off.

The Air Cycle system is interesting and super efficient: There's a scoop that takes in ambient high speed air from the outside of the aircraft. It flows through a turbine fan that is connected to a shaft to another turbine fan that turns fast enough to pull clean air from around the outside of the compression section of the jet engine(bleed air). The hot air is forced by that turbine system (ram air), through a small orifice. The physical impact of the super heated air being rammed with such force through a small orifice super cools the air to around -30F. This system also inherently pulls any moisture out of the air. Other valves provide pure hot bleed air to increase the temp of that air if it drops too low, depending on the system or area being cooled. On most weapons systems there are elaborate heat exchangers made of classified materials that this air runs through. A good example of this physical reaction of Ram Air is to blow on your hand with your mouth open (like steaming glasses to be cleaned), then blow on your hand like you're cooling it (small orifice in lips).

In Russia, I wonder if they allow for the ambient air being cold enough to cool systems and have a mechanism to turn the env system off in that case hehehe. I've read about how the trees explode from the cold there. Have you seen this happen EtherealN? Do you have to use special cold resistant tires on your car? Can permafrost be used to cool your beer? I've always dreamed of camping in the Taiga.. now THAT is roughing it.

In Russia, I wonder if they allow for the ambient air being cold enough to cool systems and have a mechanism to turn the env system off in that case hehehe.

Well, remember that russian equipment designers have to account for both the cold of sibiria, kamchatcka etcetera but also the much warmer areas in the caucasus and other areas. But the actual technology required for that isn't all that complex - just a thermostat but with the opposite function to the one in your house heating elements. :P

I've read about how the trees explode from the cold there. Have you seen this happen EtherealN? Do you have to use special cold resistant tires on your car? Can permafrost be used to cool your beer? I've always dreamed of camping in the Taiga.. now THAT is roughing it.

Haven't seen trees 'splode from the cold, but I imagine it's a very rare theoretical occurance. Off-the-cuff I'd actually suspect that it would, in that case, happen during thawing with a warmer skin contracting around a still cool (and expanded) core. Though I'm not entirely sure how trees reacting to temperature differentials, it might be the other way around. :P But even then, I would expect that it's more like a sudden crack than what we tend to think of as an "explosion". (I have seen concrete structures that have shattered due to the cold though - the switch in some places from +35 in summer to -45 in winter causes some interesting stresses on concrete that warmer climes will have a hard time imagining.)

No special tyres, no, but it should be noted that when I'm in russia I typically use taxi. Most russian cities have a taxi population that western cities can only dream of, at good prices, so no need to have your own car. :P

On cooling beer and such though, yeah, I've done stuff like that when on contract (and therefore do not have access to my fridge). I really, really, do not recommend it though since improper use can cause serious injury. (Imbibing a subzero liquid can cause severe tissue damage.)

But again, do remember that Russia isn't just a cold place. It's a cold, temperate, hot place. All depends on the time of year and where in russia you are. :)

But again, do remember that Russia isn't just a cold place. It's a cold, temperate, hot place. All depends on the time of year and where in russia you are. :)

I see your point. I knew people in Europe who thought America still had '40s gangsters and Elvis was still cool (well.. the second part's true). I guess it's easy to be swayed by authors who write books about extraordinary people in extraordinary places, and Siberia qualifies. My grandfather read 'The Last of the Breed' by Louis L'Amour to me when I was young due to my Native American heritage. In the book, the Native American is an aviator who ends up in a Soviet prison. He escapes and reverts to his Sioux roots and makes his way from the Lake Baikal area north to Yakutsk then east to the Bearing Strait. The author spends a lot of time talking about how beautiful and dangerous the land is. The Sioux meets up with a Yakut and they wage a war through woodscraft, which was interesting. I'd highly suggest the book. Hell, I think I'm going to go read it again right now.

edit: btw.. the character's biggest fear is Soviet helicopters...

If you simply lock the terrain to adjust the shkval to the point in the terrain, the rangemeasuring is active for 3 seconds!

If you lock a target (activate the automatic target tracing TA) the rangemeasuring is active for 8 seconds!

GOOD FIND!!! What page is this on?

For your second question, it's pretty easy and you were so close!

1. Laser OFF
   
2. Lock Target "TA"
   
3. Laser STNDBY
   
4. Shoot Vikhr
   

You get a laser rangefinder shoot normally every time you press the lock button so yes, you get a new rangefinder shoot on the second target.

I use two methods for attack.

First I don't turn on laser until I have valid lock and I more-less know Vikhr is in range. Then I turn it on and press again lock target.

Second method I use is during autohover. I never lock target but I put gate on target only and fire without lock. So theoritically I should extend my laser's life. But I don't. Always after second or third flight I need to repair laser.

During an MP session you can power down to get a new replacement Ka-50 so every sortie is in a fresh bird. If you are trying to fire 36 vikhrs in a single mission... get a better mission designer!

During an MP session you can power down to get a new replacement Ka-50 so every sortie is in a fresh bird. If you are trying to fire 36 vikhrs in a single mission... get a better mission designer!

So wrong! :D

- if survive for long enough to expend your laser, get a better mission designer

- if you're out of targets before you've spent your lazor get a better mission designer

;)

Panzertard's Midget-Tossers, the server where survival is miraculous. :D