The first operational prototype was made available to users in 1975 when four people could use it at the same time.

The design of the AK-630 CIWS was initiated in 1963, with the first operational prototype completed in 1964.

Once the agencies saw the operational prototype and the project"s potential, they realized that their individual sacrifices had paid off.

It seems obvious, however, that someone in the Hellstrom organization is at work on an operational prototype.

An operational prototype was displayed at Oshkosh in 2008 and its first flight occurred on 2009-03-05.

With an operational prototype in hand, the founders embarked on a campaign to raise venture capital to take the company to the next step.

CargoLifter managed to construct operational prototypes, but went bankrupt in mid-2002.

It appears that one of the Scandinavia-based telecommunication companies is also working on an operational prototype .

Single-seat operational prototypes to meet Specification F23/49, three prototypes built, further 20 development aircraft ordered in February 1954.

At least three physical demonstrators were made, but none become an operational prototype.