View attachment 323373
Estes B16 Motors
Aerostadt - The Black Widow kit was from Centuri Engineering in the mid-'60s. Centuri sold relabeled Estes motors before making their own.
The original Estes high thrust or Series II motor was the B16-x. Big core and Big nozzle with short burn time. It later was the B14-x as the designation was changed after better testing (originally on a postal scale). When the motor designations went metric (circa 1970, IIRC), the motors became B3-x. The motors required a drilling process to create the bored core and that added extra steps. This was part of the reason that they were discontinued.
A newer motor came out later designated the B8-x. It used a "pantile" to shape the slightly longer core when the black powder was pressed into the motor case. The pintles eventually wore down or broke resulting in motor failures due to crack grains. The B8s were also discontinued.
Centuri did release their "Super C" motors - the C5-0 and C5-3. Bigger core and as much propellant that they could press in. This is why they did not offer longer delays. They were great motors when they worked.
Chas