As part of the Avro Canada CF-105 Arrow program, Canadair (now Bombardier) partnered with Douglas Aircraft Company in the development of the Sparrow II (AAM-N-3/AIM-7B).
 After Douglas dropped out of this program, Canadair continued on with it until the termination of the Arrow project.

The AAM-N-3 Sparrow II was unique in that it had a fully active radar guidance system.
This combined both a radar transmitter and receiver in the missile, making it unnecessary for the pilot to keep the aircraft aimed at the target after firing the missile, unlike Semi-active radar homing (SARH) missiles which require continuous radar-assisted guidance throughout flight.
This allowed the aircraft that fired the AAM-N-3 to turn away, prosecute other targets, and/or escape from potential retaliatory missiles fired by the enemy aircraft during the time it takes for the Sparrow to reach its target.
Despite the significant advantages of this design over SARH guidance, all subsequent models of the Sparrow use semi-active radar homing.

To accommodate the active radar guidance system, the AAM-N-3 Sparrow II had a much greater volume than its predecessor.
Its size would subsequently set the precedent for all future Sparrow variants.

In 1959, Canadair had completed five missiles based on airframes from Douglas, and built two models from scratch, when the program was cancelled with the cancellation of the Arrow.
As part of the Avro Canada CF-105 Arrow program, Canadair (now Bombardier) partnered with Douglas Aircraft Company in the development of the Sparrow II (AAM-N-3/AIM-7B).  After Douglas dropped out of this program, Canadair continued on with it until the termination of the Arrow project.
The AAM-N-3 Sparrow II was unique in that it had a fully active radar guidance system. This combined both a radar transmitter and receiver in the missile, making it unnecessary for the pilot to keep the aircraft aimed at the target after firing the missile, unlike Semi-active radar homing (SARH) missiles which require continuous radar-assisted guidance throughout flight. This allowed the aircraft that fired the AAM-N-3 to turn away, prosecute other targets, and/or escape from potential retaliatory missiles fired by the enemy aircraft during the time it takes for the Sparrow to reach its target. Despite the significant advantages of this design over SARH guidance, all subsequent models of the Sparrow use semi-active radar homing.
To accommodate the active radar guidance system, the AAM-N-3 Sparrow II had a much greater volume than its predecessor. Its size would subsequently set the precedent for all future Sparrow variants.
In 1959, Canadair had completed five missiles based on airframes from Douglas, and built two models from scratch, when the program was cancelled with the cancellation of the Arrow.
AIM-7 Sparrow