Three Metres of Stroke.
Three Metres to the Trunnion.

The Pedestal Mount is the fixed-ground product of CDNS Institutional. A slewing bearing sits on a steel column; a head frame sits on the bearing and carries the elevation trunnions, the balancer and the elevation brake; one pod of tubes, or a pod either side, sits in the head. The sensor head is boresighted to the barrels. Inside the column stands the cabinet: the main disconnect, the supply, the uninterruptible supply, the controller, the fibre terminations and the track and cue computer.

What crosses into the tubes is the launch platform's own chain, unchanged. Ø90.00 mm on the bore, 3.00 m of stroke, 30 bar behind it, one normally closed breech per barrel with a port of at least 95 cm² opening in under 5 ms. The tube is seamless drawn-over-mandrel steel to ASTM A519, walled at least 6 mm, proof-tested at 45 bar, so its outside diameter is Ø102 mm and the pitch between bore centres is at least about 110 to 130 mm.

The bearing is the dividing line. Above it everything rotates and everything has to be held by a brake when a barrel fires. Below it everything is static and everything has to be held by anchors. The two halves are sized by the same 18,191 N, taken at two different levers.

Pivot a 3,500 mm barrel and the breech end swings down as the muzzle goes up. Where the pivot sits is therefore the first decision, and it can be solved rather than assumed. Taking moments about a pivot a distance c from the breech face, with the barrel and its share of the cradle acting at mid-length and the breech group acting 0.15 m aft of the breech face, the balance point falls at c = 1.46 m, near mid-length.

The head balances there with no counterweight, and the balance point does not move with tube count, because every tube carries the same masses at the same stations. At +75° the breech drops 1.41 m below the trunnion, so with a quarter of a metre of clearance under the breech and manifold the trunnion stands 1.66 m above the slewing ring.

The alternative is worth stating, because the machine is tall on purpose. Move the pivot forward to 0.8 m from the breech face to lower the head and 513 N·m per tube goes out of balance: 3,080 N·m at six tubes and 8,213 N·m at sixteen. A counterweight 0.8 m aft of the trunnion would then weigh 392 kg at six tubes and 1,047 kg at sixteen, more than half the head again, and a spring balancer of that capacity is a large fatigue-loaded component that has to hold through the shot. The balanced pivot is the recommendation, and the height is what it costs.

The reaction acts rearward along the bore, so it splits with elevation. At 0° it is 18,191 N horizontal and nothing vertical; at 45° it is 12,863 N each way; at +75° it is 4,708 N horizontal and 17,571 N down; at the −3° depression it is 18,166 N horizontal and 952 N upward. Overturning is worst at low elevation, and the anchors are designed for that case rather than for the lay the mount spends most of its time at.

At the trunnion height the balanced pivot produces, one barrel's equivalent static load puts 110.3 kN·m into the base. Spread over eight anchors on a bolt circle of 0.8 m, that is 68.9 kN each before any relief from dead load. The anchor count and the bolt circle are illustrative; the anchor design belongs to the structural engineer of record. The impulse, 357.3 N·s, is what governs base rocking and anchor fatigue, and anchor preload has to survive load reversal.

All three share the same requirements. The pier or plinth is sized for overturning and for lateral soil capacity from a geotechnical report. Frost depth and seismic design are site-specific. Anchor design follows the anchorage provisions of CSA A23.3 for the loads above, including reversal, and the designer of record is a structural engineer licensed in the province the mount stands in, working to the National Building Code as that province adopts it.

The interior-ballistics model expands its charge straight into the barrel behind the valve, so whatever holds that charge sits close to the breech and feeds it through a short, wide path. On a slewing head there are two ways to give it that. A local reservoir at each breech, refilled from the bank between shots, keeps the path shortest; it also stands a certified, registered, individually inspected vessel behind every barrel, and all of that stored energy turns with the head. A shared plenum on the head, fed through the azimuth by a hose loop, puts one vessel up there instead of one behind every barrel, and because the azimuth is ±170° the hose loop needs no rotary union. The plenum then has to refill between shots.

The bank itself is sized by the tube count and by the salvo the site asks for, and both of those are the site's to set. A charged bank is the dominant stored-energy hazard on the machine, and it is charged before anyone is near a tube, which is what sets the order of every procedure on it.

The laying envelope is no wider than the reference: ±170° of azimuth with a rear dead zone, and −3° to +75° of elevation, narrowed per site in hardware. Both axes report from absolute encoders. The head is a heavy thing to accelerate: each barrel is a 49.7 kg rod 3.5 m long, and the polar moment about the azimuth axis runs from 646 kg·m² at six tubes to 1,738 kg·m² at sixteen, and to 2,054 kg·m² for twin pods carried at half a metre either side.

A brake that let go would not spoil the shot in flight. One shot's angular impulse on a sixteen-tube head is 64.3 N·m·s, which is about 2.1°/s, and 3.8°/s on a six-tube head; over the time the round is in the bore the head turns well under a tenth of a degree. What a slipping brake does instead is back-drive the reducer and the motor, and move the lay for the next shot. The brake is therefore sized on torque and tested on holding.

Wind is the other reason the head is pinned when nobody is at the console. A sixteen-tube pod presents about 1.96 m² broadside, and the moment the wind puts on that is a fraction of the shot torque but many times what any slewing drive delivers. A sensed stow lock holds the head at a stow attitude whenever the mount is SAFE and unattended.

The two air layouts show up here as well as in the schematic. A shared plenum puts one vessel on the head; a reservoir at every breech puts one behind every barrel, so that layout adds to the head with every tube added, and the certified vessels that come with it are the larger consequence.

Four channels and an option, each specified by function and by class. A narrow day channel with zoom, for identification. A wide day channel for the near zone and the key holder's view. A long-wave thermal channel for detection and track at night. An eye-safe laser rangefinder for the range in the cue. A passive acoustic array is optional and cues bearing only.

A narrow field cannot search. The wide channel covers the envelope as a sequence of frames, so a full sweep costs the dwell of every frame in it, and a co-mounted head stops watching altogether whenever the mount lays. Putting the head on its own mast keeps it watching, at the cost of a second two-axis gimbal, a second set of drives and brakes, and their mass on a structure of its own. That is also what earns the acoustic array its place: a bearing-only cue at short range that tells the optics where to look.

What the doctrine costs is stated rather than glossed: optical detection is limited by fog, snow and rain, and without radio-frequency detection there is no warning of an aircraft before it can be seen. Detection range against a named target class comes from measurement, and none is published.

The compressor runs on three-phase at 17 kW class, specified per site, because institutional distribution in Canada is commonly 600 V or 208 V and many sites abroad run at 50 Hz. The control bus is 24 VDC, physically segregated from the three-phase side, with an uninterruptible supply behind it that carries an orderly SAFE and keeps the sensor head alive on loss of supply. Loss of power is safe regardless, because the breech is normally closed. The installation is to CSA C22.1.

The pod drives are the largest draw on that bus, and what they take rises with the pod fitted. The sizing case has both axes accelerating at once with the brakes released, the breech solenoid energized, and the sensor head, the track and cue computer, the controller and the console all running; the drives are most of that load, and everything else together is a smaller and steadier remainder. The bus, the supply and the trunk are therefore sized to the configuration actually fitted, with the conductor sized on its own resistance at temperature, inside a 3 per cent drop limit measured at the load. Where a single bus will not hold that limit, the drives move to a bus of their own and the 24 VDC side is left carrying the control load, which is the lighter and the steadier of the two.

Maintenance is the launch platform's schedule with this line's additions. At each use: the interlocks, the stop and the breech fail-closed. Monthly: harness and slew checks. Quarterly: compressor service and breech seal inspection, with seals logged by shot count. On the certificate: the vessel hydrotest and the relief proof, and a lapsed certificate takes the mount out of service. Added here: sensor window cleaning, dryer and desiccant service, a cam-set inspection and seal check, an anchor preload check, a foundation inspection, a brake holding test, a tilt-switch check and a test of the uninterruptible supply. Pedestal doors open onto service racks, the head and each pod carry lifting points, and the isolation points are the main disconnect, the compressor, the isolation valve, the vent and the local gauge.