<XMP><BODY></xmp> Jump Jet Engine Improvements





Jump Jet Improvements

        In one of Bill Sweetman's books on future aircraft he depicts a very simple but interesting design of fighter.
        It is a tailless design with the wing blended into the body. There is a ventral air intake, the shape of the canopy ahead helping channel air into this. Engine is the same Pegasus engine used in the Harrier, but using bled air to help steer and compensate for the lack of tail fin. This was a simple design that needed no great leaps of technology, but the aircraft would have been stealthy, highly maneuverable and capable of being operated from a cabbage patch.
        The Harrier jump jet has provided sterling service with the British forces, often providing air power in situations where no other aircraft could. There have been some suggestions that the Pegasus engine is particularly vulnerable to heat seeking missiles due to its forward positioned jet exhausts.
        In fairness the Harrier is a somewhat old design and future designs using the Pegasus engine could easily solve this problem. Several strategies suggest themselves:-
UPDATE
        Recently saw a film of a hovering Harrier viewed by thermal imager. The midsection of the Harrier shows a lot of heat. The same program showed that RAF Harriers routinely fire flares as they make an attack.
        Another system is DIRCM -Directional Infra Red Counter Measures-a laser system that can blind heat seeking missiles.

DIRCM
http://www.fas.org/man/dod-101/sys/ac/equip/an-aaq-24.htm

        Such a system should be mounted on the centreline between the wheels of every Harrier.

        The British GR5 harriers have a different defensive avionics system to marine A-8B Harriers. To quote this page:

        "The GR.5 also has a somewhat different avionics kit than the AV-8B. Although the British were happy to retain the AV-8B's ARBS, they did incorporate a Ferranti moving-map display, their own radio and IFF systems, and fitted entirely different countermeasures. The countermeasures kit includes a Marconi Zeus ECM system, a Plessey "Missile Approach Warning (MAW)" system, and Swedish Bofors BOL chaff dispensers. The Zeus includes an RWR that can identify 1,000 different types of emitters and activate its self-defense jammer automatically to meet a specific threat. The MAW can automatically dispense chaff when a missile attack is detected".

Ralph Zumbro writes:
        Rework the landing gear, pull the standard wheels and install the tracked landing gear that we've had since 1940, and the Harrier can land anywhere. That plane can actually live with the troops. On the ground, Out in the hills. With the choppers.


        I've done some further research on the supposed vulnerability of the Harrier.
        I haven't found much information on Harriers lost to enemy action. Harriers killed in combat seem to be very few. One aircraft in the Falklands was taken by either a Blowpipe or Roland Missile (sources differ), the others by AAA. None were taken by Argentine Air to Air Heat-seeking missiles. There are no details of how the ones claimed to be taken by the Serbs were destroyed, but I suspect that this was probably triple A too. Most sources deny the Serbs shot down any Harriers.
        Five USMC planes were lost in the Gulf, 4 being attributed to IR missiles, but given the number of sorties flown (3,567) this is pretty modest number. It probably compares very favourably to losses of other aircraft.
        All the complaints about the Harrier are based on no evidence at all. 4 USMC planes lost in over 3000+ missions probably gives it a better record than many conventional designs. What does this tell us statistically? -nothing! Sample groups are too small!
        Vulnerability to IR SAMs?-certainly a hit will be more damaging than a conventional layout -but there is no evidence that Harriers are a IR magnet that is more likely to be hit. A F-18 is more likely to limp home than a harrier , but it's a twin engine plane, so probably more likely than most single engine designs.

Harrier Operations
http://www.geocities.com/Area51/Capsule/6480/HarrierIa.htm
http://www.periscope1.com/demo/weapons/aircraft/attack/w0003089.html
http://www.britains-smallwars.com/Kosovo/RAF.html
http://www.aeronautics.ru/official/lostplanes.htm

Kosova -no losses

http://www.balkanunity.org/yugoslav/english/losses.htm

Balkans. One Harrier lost - attacking system unknown


        Although there is no evidence for the Harrier being more vulnerable to heat-seeking missiles it is true it is not a particularly well protected aircraft.

Chuck Myers: our (OSD/Joint) formal two year intensive aircraft vulnerability study (circa 1985-87) of all tactical aircraft awarded the AV-8B the prize as being THE most vulnerable aircraft to small arms fire. As you would expect, the A-10 was the least vulnerable and by a factor of ten.
         .......there was no armor, no foam in the fuel tanks to inhibit explosion, fuel encased inside the walls of the INLET DUCT (unbelievable), and main fuel stashed directly above the engine with NO FUEL TANK SELF SEALING! I don't recall having flown a Navy fighter/ attack airplane which lacked self-sealing tanks.
        The Harrier is so short on fuel that they cannot tolerate the volume/ weight toll that selfsealing and foam in tanks would take on range/ loiter.

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