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Elite 1K Joined: Aug 02, 2006 Posts: 1003 Status: Offline

There has been much rumors and interest over installing a laser in the F-35 for defensive and/or offensive purposes. I think that an aerial active defense system is probably more feasible and effective.

I propose the following idea:-

(1) The Aerial Active Defense (AAD) is similar in concept to active defence grenade dispensers currently being developed for anti-RPG/ATGM defence on tanks.

(2) The system is based on a 4"x24" projectile weighing about 30 lbs each and carrying a 5 pound directed fragmentation warhead. It has four stabilizer fins which unfolds in the rear but has no aerodynamic controls. The only means of steering comes in pyrotechnic divert and pitch control thrusters. The projectile carries a short range millimeter wave seeker/proximity-fuse.

(3) The projectiles are carried in two dispensers -- one facing upwards and one facing downwards -- of 2x3 cells each for a total of 12 projectiles. Each dispenser covers a 240 degree hemisphere. The total system weight include the dispensers and projectiles is around 500 lbs.

(4) The system is fully integrated with the Distributed Aperture Sensor (DAS) imaging IR system on F-35. It has only two modes of operation -- ON and OFF.

(5) When the DAS system and the F-35's integrate defense software determines that an AAM or SAM is within ~3km of the F-35, it computes a precise vector to the approaching missile, downloads it to AAD launcher.

(6) The AAD launcher ejects a projectile into the appropriate hemisphere using a soft launch gas generator charge.

(7) The projectile -- with the vector of the approaching missile in memory -- pitches over to an intercept vector by firing the four aft mounted pitch control thrusters once separated by the appropriate timing delays.

( Cool

Next, the short range MMW seeker locks onto the target and the booster motor fires accelerating the projectile to ~Mach 1.5 (relative speed to aircraft).

(9) The seeker and simple electronics activates the set of lateral divert thrusters mounted at the projectile's center of gravity refine the intercept aim. When the projectile gets close enough to the incooming AAM it detonates its warhead destroying or disabiliing it.

(10) Typically two shots are taken on every incoming AAM/SAM with an expected intercept distance of between 15m to 1.5 km.

Click here for full size rendition... http://img72.imageshack.us/img72/3237/aadphotoshopih7.jpg

Click here for full size rendition... http://img413.imageshack.us/img413/9418/aadinterceptyj4.jpg

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Enthusiast Joined: Jul 30, 2006 Posts: 50 Status: Offline

It would probably be more practical to just develop better flares/radar cartridges. You wouldn't suffer a 500lb weight penalty, for instance.

Elite 1K Joined: Aug 01, 2006 Posts: 1003 Status: Offline

mil_hobbyist wrote:

It would probably be more practical to just develop better flares/radar cartridges. You wouldn't suffer a 500lb weight penalty, for instance.

Unfortunately, I don't think flares work AT ALL against imaging seekers. The missile actually sees the shape of the target like your digital camera sees you in a photo these days. There is no way to fool it using a stick of flare with a blob of an IR signature. Flares only work against older threats with non-imaging IR seekers, and then only the less sophisticated ones -- doesn't even work against the likes of the AIM-9M.

Similarly, most modern RF AAMs like the AMRAAM is basically 99.9% chaff proof. They don't ever go for the strongest radar return, they go for the one most akinned to the one it was following previously. This is why there is a rush to field towed missile decoys which tries very hard to mimic the aircraft's exact radar return based on the active signal it receives from a potential threaat -- we already see this effort on the Typhoon and the F-18E/F

F-16.net Editor Joined: Sep 23, 2003 Posts: 2862

Hard to say... JSF is still figuring out the basics in testing.

STOVL JSF is weight creeping again a few hundred pounds over that famous weight reduction event.

CV JSF (someone correct me) has some minor target weight issues.

Something like this, at this stage will just make an engineer cry, having to re fudge target weights.

How about the laser thingly that is being deployed on FED-X MD tri jets?

Elite 1K Joined: Aug 01, 2006 Posts: 1003 Status: Offline

elp wrote:

Hard to say... JSF is still figuring out the basics in testing.

STOVL JSF is weight creeping again a few hundred pounds over that famous weight reduction event.

CV JSF (someone correct me) has some minor target weight issues.

Something like this, at this stage will just make an engineer cry, having to re fudge target weights.

How about the laser thingly that is being deployed on FED-X MD tri jets?

This thing?

Detailed Info (pdf)....
http://www.dsd.es.northropgrumman.com/DSD-Brochures/dircm/AAQ24.pdf

Its about 150 pounds total with the "small" laser and ~130 pounds total with the "mini" laser. The AN/AAQ-24 NEMESIS detects, tracks then accurately apply its laser to blind and/or damage the seeker on the missile. It is quite effective in tests against Stingers with newer the focal plane array seeker. But, this device has zero value against an RF missile and may or may not be able to cope with multiple inbounds or inbounds in quick succession. Also, thus far it has only been applied on helos and larger transport aircrafts. It is unclear whether it is able to cope with a platform which itself may be aggressively maneuvering.

IMHO, Circa 2015, the F-35 and similar jets WILL have a similar device. The size and weight penalty is minimal especially if it is integrated with a platform like the F-35 which does not need its separate processor or distributed sensors since DAS and the integrated defense software are present. The weight penalty will simply be around 50 lbs for the laser turret. Assuming that two turrets are used to provide upper and lower hemisphere coverage it is still ~ 100 lbs. Peanuts really for a 27,000~30,000 lbs jet.

I think the F-35 should have both a directed energy laser (softkill) and a hard kill interceptor. There is nothing more frustrating for the enemy than a platform, which is extremely difficult to find and shoot at to begin with, that also has the ability to kill the majority of otherwise good missile shots throw at it. First you can't find it. Then you can't easily before it shoots and kills you. When you finally luck out and are able to put a good missile shot on it it is very good at jamming or spoofing your missile. Finally, if that fails it'll simply shoot down your missile most of the time. Thats enough to drive the enemy nuts.

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Aerial Active Defense for F-35