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A-60 and YAL-1 airborne laser versus F-35.

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  • St. John
    replied
    Some information about adaptive optics here too.

    https://books.google.co.uk/books?id=...%20ALI&f=false

    Leave a comment:


  • St. John
    replied
    Some interesting information on phased array lasers in this extract about Zenith Star, which was an SDI-related laser project.

    https://larouchepub.com/eiw/public/1...onstration.pdf

    Leave a comment:


  • stealthflanker
    replied
    It might be accidental instead of deliberate.

    British however were having a concept for protecting the pilot tho. In their P-125 concept.

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  • St. John
    replied
    A naked human eye, but don't pilot visors have inbuilt protection? And I should also point out that using lasers for such purposes would be a breach of the Geneva Convention.

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  • stealthflanker
    replied
    Nice

    and yes. that's why we have laser safety.

    I wish i could improve on providing some form of atmospheric consideration. as the original book Dave Hafemeister's Physics of Societal Issues does not go in depth for it.
    and thanks for the book. Now we can expand our target hardness data.

    Leave a comment:


  • garryA
    replied

    Click image for larger version

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    https://books.google.com.vn/books?id...page&q&f=false

    10J/cm2 needed to damage optical sensor
    1J/cm2 needed to damage pilot's eye
    I took 100kW for F-35 HEL with a mirror diameter of 20 cm.
    It can blind IR sensor from 70km in 10 seconds
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    It can blind human eye from 100 km in 1 second
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    By contrast, YAL-1 need about 0.5 second to blind human eye from 1000 km
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  • stealthflanker
    replied
    mig-31bm can't assure that the laser will point at the same area. Remember Ballistic missile can spin as means to resist Laser, letting the area being exposed cool down. Same as Aircraft, and aircraft can do it more freely without fearing of being miss. And no, unless the cockpit is exposed, you wont instantly blind pilot. Thus why you want the engagement time as short as possible. Aside from multiple target engagement. Once laser weapon become common i would expect LWR to be more common to warn pilot that he's being exposed.

    Maybe we can take this study to estimate how many aircrafts needed to saturate the laser based on its engagement time.

    https://www.scribd.com/document/3902...issile-Defense

    We assume the aircraft need to cover 100 Km of range for launch point. mach 0.9. 1 min engagement time. The laser will be saturated by 5 aircrafts. If we have faster aircraft like Mach 1.3, 4 aircrafts will saturate the laser. and so on. If longer ranging missile can be deployed, there could be no aircraft downed and the laser will need to deal with missiles. 1 F-35 can carry or expected to carry Meteor with some 160 km range and may carry as many as 4. and meteor might sustain up to M-3. surviving aircraft can deploy 4 missiles, the laser may have to deal with it and given that M3 missile will cover 150 Km range in just 2 minutes. The laser will be saturated by just 2 missiles, the third might get through.


    garryA I'm already put the spreadsheet. start pulling the numbers. and you seem to have good source too.

    Leave a comment:


  • garryA
    replied
    stealthflanker
    The laser makes no difference. You will need about 25MW, 3 m mirror assembly to engage aircraft target (25 Kj/sqm hardness) at 250 Km in 1 second engagement. If you desire capability against typical aircraft we have. 100 KW of same laser will do the same but at 1 Minute, meaning you have to aim for a full 1 minute against that target and there could be another one launching missile at you. Smaller mirror assembly will obviously doing less, meaning you have to illuminate the target much longer to obtain the necessary fluence. 1m diameter mirror with 100 KW laser will need 10 Minutes to get enough fluence to do the same job.
    Can 100 kW laser with 30 cm diameter mirror blind IR sensor from 50 km away?
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  • mig-31bm
    replied
    You can move the focal point by moving the lens, it is similar to how you zoom in and out

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  • St. John
    replied
    Okay, that's interesting but can they vary the focal point? Can they put the focal point at any range? The other point which I think stealthflanker is getting at is how to aim your laser at fighters 20+km away. +/- 1 millirad gives +/- 20m left, right, up and down, could you usefully aim at an F-35/F-22 at 100km?

    Leave a comment:


  • mig-31bm
    replied
    stealthflanker : I think it is very easy for the lens/beam to follow a maneuver aircraft at long distance, because the angular velocity is very small. If the aircraft was moving at 2000 km/h (0.55 km/s) tangent to the optics and the distance is 250 km, the angular velocity is only 0.13 degrees/second

    Leave a comment:


  • mig-31bm
    replied
    St. John
    Firstly, the image is for 100 kW laser, 20 times weaker than YAL-1s laser
    Secondly, you are treating a FOCUS laser beam the same as a radar beam aka beam spot getting bigger with distance but that not how it work. You burn target at your focal point. The area of the melting spot will actually get smaller until the focal point, that why they need those massive lens

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  • stealthflanker
    replied
    You dont solve natural factor. can only have partial remedy. or constrain the operational scenario of the laser.



    Leave a comment:


  • St. John
    replied
    Phased array lasers have been invented but that doesn't solve the problem of atmospheric attenuation or beam divergence.

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  • TomcatViP
    replied
    Magneto optic is blooming

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  • stealthflanker
    replied
    The thing is that. As long as we still using mechanically steered laser. You would want the biggest power and mirror assembly you can get.

    We are not yet in era where laser is electronically steered. Maybe then we can actually engage multiple targets and "time share" the laser so the beam will always point at hopefully same spot.

    Anyway. I put my calculations in an excel spreadsheet long time ago :

    http://www.mediafire.com/file/r25cdq...Calc.xlsx/file

    It based on "Physics of Societal Issue"

    You can trade off various parameters namely power, engagement time, target hardness and mirror assembly size. Wavelengths and radiation absorbed by target too.
    Click image for larger version

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    For radiation absorbed by target, you can use following chart

    http://www.eepw.com.cn/article/201604/289592.htm
    Last edited by stealthflanker; 6th December 2018, 10:54. Reason: addition of excel spreadsheet

    Leave a comment:


  • St. John
    replied
    MiG-31 I'm going by your own image which plots the power on target at specified ranges with specified laser powers. E.g. at 20km range with a 1000kW laser, the power on target is 39kW.

    Ah okay, page 54 last para gives specifics. At 5km the spot size is 75cm^2, so at 20km it will be 16x75cm2 = 1200cm^2. With a 100kW laser Figure 28 shows 39kW on that target area at 10,000m altitude and 20km range. So that is 32.5W/cm^2. After many minutes that could probably cook a turkey. To get a useful 1kW/cm^2, you would need approximately 3MW and 20km would hardly keep you safe from MRAAMs or LRAAMs.
    Last edited by St. John; 6th December 2018, 10:43.

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  • stealthflanker
    replied
    yeah, but that assume the aircraft is not maneuvering and your tracking system and whatever actuator controls the mirror assembly can follow if it maneuver.

    and remember. You may face multiple aircrafts and multiple missiles. 1 minute may just not be practical and remember that missile can also come from the side not covered by the laser.

    Leave a comment:


  • mig-31bm
    replied
    How about 1 m diameter mirror with 2 Mw output such as YAL-1 and A-60
    anyway, If it takes 1 minute for 100 kW laser to destroy an aircraft from 250 km, that is a very short amount of time, for comparison, you need a missile constantly moving at Mach 12 to do the same thing, and missile can be evaded but you can't evade a laser beam. Furthermore, that beam will blind the pilot immediately.

    Leave a comment:


  • stealthflanker
    replied
    No difference than engaging AEW or other large aircraft. Both YAL and A-60 are large aircraft with large RCS and potentially large heat signature too due to need of exhaust for cooling their laser assembly.

    The laser makes no difference. You will need about 25MW, 3 m mirror assembly to engage aircraft target (25 Kj/sqm hardness) at 250 Km in 1 second engagement. If you desire capability against typical aircraft we have. 100 KW of same laser will do the same but at 1 Minute, meaning you have to aim for a full 1 minute against that target and there could be another one launching missile at you. Smaller mirror assembly will obviously doing less, meaning you have to illuminate the target much longer to obtain the necessary fluence. 1m diameter mirror with 100 KW laser will need 10 Minutes to get enough fluence to do the same job.

    Leave a comment:

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