The first K-49, BT-50 based Estes Sprint was introduced in 1970. It was advertised as "The First True Competition Model".
To see the catalog page, CLICK HERE
Very few models had boat tails back then. The Sprint sported a low drag parabolic nose cone and fin shape. It used 18mm engines, streamer recovery and came with two different decal motifs.
On the original the boat tail was formed from card stock. There was no engine hook, the engine was friction fitted with masking tape.
The old Sprint stood 13.8" tall.
The newer Sprint XL is an upscale model built around a BT-60 and uses 24mm engines.
"In memory of Mike Dorffler (1946-2010), longtime Estes Model Rocket Designer." Mike Dorffler designed other models including the Estes Cineroc.
The Sprint XL is 22.8" tall.
The Sprint XL build starts tomorrow!