CRV7

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The CRV7 is a 2.75 inch folding-fin ground attack rocket produced by Bristol Aerospace in Winnipeg, Manitoba. When it was first introduced in the early 1970s it was the highest performing 2.75 inch (70 mm) rocket (the standard US size) in the world, the first with enough energy to penetrate standard Warsaw Pact aircraft hangars. The CVR7 remains the most powerful rocket to this day, and has slowly become the de-facto standard for Western-aligned forces, at least outside the United States.

The CRV7 was an offshoot of earlier research at CARDE into high-performance solid fuel rockets in the late 1950s, performed as a part of a general program studying anti-ballistic missiles. This program led to the Black Brant rocket, and CARDE and Bristol decided to use the same propellant and engine design for a new 2.75 inch rocket motor. Compared to the US MK4/MK40 Mighty Mouse rockets the CRV7 replaced, the higher energy fuel and newer fuselage design led to a longer and much flatter trajectory, and twice the energy on impact.

The resulting C-14 engine was first produced in 1973, with:

total impulse of 2,320 lbf·s (10.3 kN·s)
mass without warhead 6.6 kg
typical mass of warhead 4.5 kg
burn time 2.2 s
burnout range 1.1 km
range 3.6 km

However the aluminium-based fuel generated considerable amounts of smoke, and was therefore suitable for launch only from high-speed aircraft, which would quickly clear the plume. This led to the development of the C-15 engine, which did not include aluminium and produced considerably less smoke, with a slightly smaller impulse of 2,185 lbf·s (9.7 kN·s). The latest C-17 and C-18 engines offer slightly lower impulse at 1,905 lbf·s (8.5 kN·s), but with almost no smoke at all.

The CRV7 had just been introduced into Canadian Air Force service when it was entered as a part of a general competition in France. One part of the competition required the contestants to hit a tower with unarmed rockets. The Canadian pilot hit it on his first try, but aimed as if he was firing the much lower-powered MK4 and was therefore close enough that the rocket still had considerable energy. The rocket destroyed the tower and he was disqualified because the judges refused to believe it was unarmed.

The CRV7's energy was so high that testers were surprised to find that hardened-rod practice rounds were penetrating the decks of ships used for target practice. Study into this effect led to the FAT warhead, Flechette Anti-Tank, containing 5 tungsten-reinforced steel flechettes that can penetrate the armour of the most modern tanks.