Airforces

were greatly reduced in size. The tail rollerons

were also discarded. The forward surfaces

are fixed, with all-moving tail surfaces. The

German-designed IRIS-T has four small fixed

fins on the forward body, four long-chord mid-

body wings and cruciform tail control surfaces.

The AIM-9X and the IRIS-T use thrust-vectoring

control, which is absent on the ASRAAM.

Underlying the differing missile configurations

were varying approaches to the ‘within visual

range’ (WVR) fight. A key design driver for the

UK ASRAAM was to engage the threat as early

as possible to avoid a ‘furball’, amid increasing

concern over the risk of a mutual kill outcome.

The low-drag airframe together with a sensitive

seeker and powerful rocket motor allows for

intercepts at ranges that previously have not

been considered within the WVR envelope.

The ASRAAM has a greater body diameter

than either the AIM-9X or IRIS-T, allowing for

a larger and, therefore, more powerful solid-

propellant motor. The disadvantage is that this

approach sacrifices some manoeuvrability in

the very close engagement arena, given the

missile’s acceleration as it leaves the rail and the

tail-control only approach. When the ASRAAM

was being pitched to the US, consideration was

given to reducing the initial thrust by around

5% to improve performance in a very close-

in engagement. The ASRAAM’s peak speed is

believed to be around Mach 4 with a kinematic

range well in excess of 18.6 miles (30km).

While the ASRAAM has a diameter of around

6.7in (170mm), the AIM-9X and IRIS-T stick to

the classic Sidewinder diameter of 5in (127mm).

In the case of the AIM-9X, this was driven by

the intent to reuse a number of components

from the AIM-9M Sidewinder including the

Mk36 solid-propellant motor and the WDU-17/B

warhead. Improved manoeuvrability was

provided by rear control fins in conjunction

with thrust vectoring. An initial operational

capability (IOC) was declared for both the US

Navy and the USAF in 2003. The baseline 9X,

however, was a ‘lock-on before launch only’

missile and retaining the Mk36 motor restricted

its range. The Block II upgrade reached IOC

in 2015, with a lock-on after launch mode

through the addition of a data link. Improved

range was provided through trajectory shaping,

most likely using a lofted fly-out. A further

range extension was at the heart of the now

shelved AIM-9X Block III, which would have

introduced a wider-diameter body to house a

larger motor. Instead, a more modest Block II+

effort will swap out obsolescent components.

While the AIM-9X and ASRAAM both use a

staring focal plane array seeker, and up until

recently the same design, the German-led IRIS-T

opted for a scanning array. The seeker had been

developed by Bodenseewerk Gerätetechnik

(BGT) as part of the Family of Weapons MOU

and was intended for the ASRAAM. The

collapse of collaboration, however, saw the then

BAe Dynamics pursuing a different seeker for

the ASRAAM. Meanwhile, Germany became

the core around which a group of NATO nations

(Canada, Greece, Italy and Norway) along with

Sweden would coalesce to develop an IIR

AAM, the IRIS-T (Infra-Red Imaging System –

Tail/Thrust Vector Controlled). It retained the

Sidewinder diameter, but adopted a considerably

different aerodynamic configuration, the most

obvious element being the addition of four

long-chord mid-body wings. Thrust vector

control allied with four all-moving rear control

fins provides manoeuvrability. The missile

entered service with the Luftwaffe at the

end of 2005 and, like the AIM-9X, its design

traded range for increased manoeuvrability.

France’s hybrid

Europe’s other IIR-guided AAM is the Mica IR.

Rather than design a direct successor to the

Magic 2, France opted to develop a common

airframe to meet both active radar-guided and

IIR missile requirements, providing the benefit

of commonality. This, however, came at the

cost of compromises in the traditional design

parameters of ‘dogfight’ and medium-range

missiles. The Mica IR entered service in 2003.

Work is now under way on a successor to

the Mica, the Mica NG (Nouvelle Génération).

The project is being led by MBDA France

and, so far, little detail has been made

public by the French defence ministry.

Given developments in seeker technology,

however, the Mica NG could include a

dual-mode seeker with a combined radio

frequency (RF) and IIR seeker package.

Above: Inert AIM-9Xs prepared for loading on US Navy Super Hornets ahead of the day’s training at NAS
Oceana. Like the IRIS-T, the AIM-9X employs thrust-vectoring control for enhanced agility. Jamie Hunter

Right: The PL-10 (here in its export guise) was

initially known as the PL-ASRM (PL-Advanced

Short-Range Missile) and features a multi-element

IIR seeker, laser proximity fuse and thrust-

vectoring. It entered service in 2016. Below: A live

Mica IR on the wingtip of a Rafale. France elected

to use a common airframe for both its radar-guided

and IIR missiles. Henri-Pierre Grolleau

A Typhoon from No 3 (Fighter) Squadron at RAF Coningsby, Lincolnshire, fires

an ASRAAM against a flare pack towed by a Mirach target drone over the

Aberporth range in Cardigan Bay, Wales. Eurofighter/Geoffrey Lee

About the authors

Douglas Barrie is senior fellow for military

aerospace at the IISS. Piotr Butowski is a

freelance defence aerospace journalist.

AFM

http://www.airforcesmonthly.com #362 MAY 2018 // 65