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Background
— Tactical UAV — CU-161 Sperwer Development |
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Sperwer was developed to meet a late ’90s Dutch army requirement[1] for a tactical UAV. Its lineage
is rather complex. The SAGEM Crécerelle[2] is its immediate ancestor but that shorter-range UAV is
derived, in turn, from the MDS Banshee, a British target drone. Both earlier designs shared the delta
winged form of the new CF Sperwer tactical UAV.
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“... Noses must be of some shape or other ... ”
The CU-161 Sperwer is fairly conventional for a
modern Tactical UAV. Its airframe design has been contrained by the need to position turret- mounted sensors close to
the UAV’s nose. As a result, the Sperwer’s powerplant is in its tail driving a 4-bladed,
pusher propeller. Sperwer’s small delta wings, angled twin tails, and simple rectangular
fuselage-section all serve to lower the vehicle’s radar return signature. The Sperwer
airframe was also designed to be as compact – and, therefore, portable – as possible.
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‘Moving Forward with the Agenda’ — Sperwer’s Motive Force
The small size of the Sperwer is quite evident in the factory view (at right). Also visible is the
starboard engine radiator – one of two mounted on either side of the fuselage beneath each vertical
tail. Liquid-cooling is somewhat unusual for small 2-stroke UAV powerplants but serves to reduce engine noise,
making Sperwer harder to spot. The two-cylinder engine generates 48 kW (65 hp) at 6500 rpm, an impressive
output considering its tiny 850 (35 cu in) displacement. Still, the power surplus of a CU-161 is marginal, severely
restricting its Afghanistan ‘hot-and-high’ performance. SAGEM has made improvements [3] but too late
for the CU-161.
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On Launching the Legless ‘Little Hawk’ Aloft
Sperwer’s pneumatic rail-launcher is carried by a 10-tonne truck. [4] Sperwer sits in a
cradle which is propelled along this elevated rail to gain flying speed. Post-mission recovery is via a 117-square
metre parachute – which deploys from a hatch in the upper
fuselage. The landing is cushioned by airbags under each wing as well as the fuselage.
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Control Freaks — Small Hawk s, Lots of Information
The forward-fuselage airbag protects the CU-161’s sensor (‘orientable line-of-sight payload’
– that’s a video camera to you and me!). This camera is mounted in the prominent ball-turret
beneath the nose. Ground-based operators use a joystick to aim this video camera, generating live images.
Alternatively, the camera can be locked onto a target while the Sperwer manoeuvers, or the CU-161 can be
instructed to follow the camera’s line-of-sight. A fixed, video camera in the CU-161’s nose gives
operators a forward-looking, wide-angle view of ‘their’ flightpath.
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[1] Explaining the use of Sperwer instead of Épervier for ‘Sparrow Hawk’. Since
entering Dutch service, the Sperwer has been adopted by France – to replace the old
Crécerelle (Kestrel) in the tactical UAV role – as well as Sweden, Denmark, Canada, and
most recently, Greece.
[2] Crécerelle was a low-risk battlefield reconnaissance platform mounted on a well-proven
airframe. The French 7th Arty Regt took their Crécerelle to Macedonia (where they operated
alongside CL-289s and Bundeswehr Luna). These operational
trials were successful but, showed the need for greater speed and range. Sperwer provided a ready alternative
and will be replacing both the CL-289 and Crécerelle.
[3] SAGEM refers to the CU-161 TUAV as a standard Sperwer (with its simple, 4.2m span delta wing). SAGEM
went on to develop a long endurance model (now called the Sperwer-B) distinguished by its extended, 6.2-metre span
wing. Sperwer-B has been shown with canard control surfaces which , like the extended wing , derive from those of
the turbojet-powered Sperwer HV (Haute Vitesse) ‘deep penetrator’.
[4] As delivered to the CF, the Sperwer launcher (or LANS to its makers) was mounted on a six-wheeled Renault
Kerax truck. The Renault 10t was obviously on loan from SAGEM (the original Sperwer operators, the
Koninklijke Landmacht, use smaller DAF YF-4442 trucks for their lanceersysteem). Canadian
Sperwer (now under Air Force control) are now launched and recovered by the standard CF HLVW truck.
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