Added 18-6-09
Updated 3-5-24
Scrapboard contributor Nate Turner and myself were discussing what features would be desirable in an aircraft intended for Close Air Support and Manoeuvre Air Support.
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The design we came up with Nate named “Cassie”. He also produced a very fine image of the proposed aircraft (right).
We decided on the following features:
Twin VSTOL type engines, with exhausts shielded by tail. We decided to give the aircraft a STOVL capability and opted for a pair of engines using the same V/STOL system as the F-35. The space between the engines can be used for extra fuel, an internal weapons bay and additional sensor or defensive systems.
When hovering, the rear nozzles are pointed down and direct their force through the space before the tail. In level flight, the nozzles direct their force over the tail planes.
Like the tail of the A-10, the tail is designed to hide the exhaust nozzles from many likely targeting angles, making it harder for IR homing missiles to lock on. Also like the A-10, the components of the tail are ambidextrous to simplify repairs and spares supply.
A gimbal/turret-mounted laser range-finder and designator system so the aircraft can mark targets for weapons irrespective of its course and heading.
Turreted 25mm gun. We decided not to give Cassie a weapon such as the GAU-8 30mm Avenger cannon. While there can be little doubt that this is an effective weapon, it needs to be asked just how cost/mass-effective it is?
GAU-8 itself weighs 620 pounds (280 kg), but the complete weapon, with feed system and drum, weighs 4,029 pounds (1,828 kg) with a maximum ammunition load: about 16% of the A-10's total unladen weight.
In Iraq, many pilots decided that descending to gun range was not prudent and targets were better engaged with missiles. 4,029 pounds is a lot of weight to carry around if the weapon may not be used, and we both agreed Cassie could manage with missiles and a smaller cannon, and that the lift capacity could be better used for systems such as armour, sensors, ordinance and ammunition.
Instead of a GAU-8, Cassie would have a ventrally mounted 25mm gun, possibly a variant of the GAU-12_Equalizer. When moving at high speed, the 25mm cannon would be locked in position so that it fires forward through an opening in an aerodynamic faring. When the Cassie is moving at slower speeds, the 25mm gun can be lowered and traversed.
The Cassie does not need to lose altitude to fire on a ground target. It can remain at a constant altitude or even climb while firing. Likewise, the Cassie does not need to fly towards a target to fire at it. It can fly a parallel, orbiting course or even a divergent course.
For further discussion of this topic see my article on Orbiting Fire.
Mark LaSalle makes the valuable suggestion “The Ventral mounted weapon should have an interface with the flight control computer so it can be ‘accounted for’ during all manoeuvres. Have a way to pin it in place, both to restrain it from moving during maintenance and for battle damage repair purposes. Reduced functionality is better than none. A traverse motor/actuator failure shouldn't make it Non Mission Capable.”
Another distinctive feature of Cassie is its ventral canards. These were experimented with on the CCV and AFTI versions of the F-16 and allowed the aircraft to manoeuvre in one plane without movement in another, for example, turning without having to bank. The CCV/AFTI could also point its nose towards the ground without losing altitude or point its nose at an angle to the direction of travel. One of the advantages of this fine degree of control was that weapons could be delivered with increased precision. It was claimed that the F-16 CCV/AFTI could drop dumb bombs as accurately as other aircraft could use guided missiles. Such a level of control and manoeuvrability in Cassie would be useful when delivering bombs, missiles or FFAR.
For self-defence, Cassie carries air to air missiles, some of which can be launched from dorsally mounted rails or weapon bays.
To maintain a good thrust to drag ratio, part of the Cassie's armament will be carried in an internal bay or recessed mountings.
Provision to carry external stores would also be available for when the situation allows, and some of these hardpoints would be plumbed so external fuel tanks can be used.
While there is a wide variety of ordinance the Cassie might carry, the most likely weapons include
In “Antitank”, Richard E. Simpkin suggests an air‑to‑surface anti‑tank missile with a 30 kg HEAT warhead for launch from fixed‑wing aircraft. This was intended to have an increased disruptive effect on the target in addition to any penetrative damage. Against lightly armoured targets such as APCs, the increased blast effect had a greater chance of also disabling the occupants. Such a missile would be a more mass‑efficient alternative to Maverick. The AS.15 and AS‑20 gives some idea of the size and total mass such a missile might have.
Simpkin also suggest (p.211) “cluster rockets” carrying smartlets, minelets and/or bomblets. The use of a rocket for delivery allows the cargo to be launched from a low flying aircraft at a standoff distance. The rocket ascends to an altitude that allows sufficient time of descent for the mechanisms of the bomblets to arm. Possibly, a low-flying rocket could eject minelets downward and to the sides while ejecting bomblets upward.
Cassie‑KISS (or Cassie‑Lite) is a simplified, lower cost version of Cassie, for applications where quantity may be preferable to quality.
The most obvious difference is that Cassie‑KISS is a conventional take-off and landing (CTOL) aircraft. STOL and rough landing field operation will remain priorities.
I tend to imagine Cassie‑KISS as a twin engine aircraft along the lines of the OA-37, Saab A32 or BAE Strikemaster, although probably with a tandem cockpit configuration.
How simple an aircraft may be and still survive a modern battlespace needs to be determined.
Intended for the CAS, COIN and local interdiction roles, the Cassie‑KISS would need to be able to carry a useful load of anti-armour weapons such as Hellfire, Brimstone and Maverick. This, in turn, might require relatively sophisticated target acquisition and weapon interface systems. It is possible that a modular configuration would allow such systems to be fitted only when a need for them was anticipated.
Cannon armament would be a 25mm weapon. This might be a fixed weapon, a turret or some hybrid system with limited traverse and/or depression.
By the Author of the Scrapboard : | |
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 | Attack, Avoid, Survive: Essential Principles of Self Defence Available in Handy A5 and US Trade Formats. |
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 | Crash Combat Fourth Edition Epub edition Fourth Edition. |
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