The 1929 Alexander Eaglerock A-12 (ATC 139) was designed by Ludwig Muther (A-12 to A-15) and priced at $5,849.

Eleven were built, a few of which were refitted with 165hp Comet 7-E under reissued (ATC 2-1).

Eaglerock A-12
Engine: 130hp Comet 7-RA
Length: 24’11”
Useful load: 953 lb
Max speed: 112 mph
Cruise: 94 mph
Stall: 40 mph
Range: 650 mi
Seats: 2

The 1928 Alexander Eaglerock A-11 single-place open cockpit biplane NX6315 was rebuilt as A-14, ended up with Mathewson Airways in Detroit, most likely serving as a mail plane.

Engine: 110hp Warner Scarab

Two 1928 Alexander Eaglerock A-7 conversions were built; NX4570 and NX4753.

NX4570 was destroyed in a hangar fire, and ATC 2-1 Group 2 approval was cancelled.

Engine: 125hp Ryan-Siemens
Wingspan: 36’8″
Seats: 3

Two or three of the 1928 Alexander Eaglerock A-5 were built. One as entry in the 1929 National Air Tour piloted by Ben O Howard.

Eaglerock A-5
Engine: 260hp Menasco-Salmson B-2
Wingspan: 36’8″
Length: 23’10”
Seats: 2

The 1928 Eaglerock A-3 (ATC 59) was powered by a 150hp Hisso A or 180hp Hisso E. they were priced at $3,250.

The 1928 Eaglerock A-4 (ATC 59) was the same as the A-3, but with a 180hp Hisso E, and a nose radiator. A total of ninety-three A-3 and -4 were built.

Eaglerock A-3
Engine: 150hp Hisso A
Length: 24’10”
Useful load: 741 lb
Max speed: 114 mph
Cruise: 97 mph
Stall: 40 mph
Range: 475 mi
Seats: 3

Eaglerock A-3
Engine: 180hp Hisso E
Max speed: 120 mph
Cruise: 103 mph
Stall: 40 mph
Range: 570 mi
Seats: 3