By 1928 the Halton Aero Club HAC.1 Mayfly had been converted from a biplane to a parasol monoplane and was renamed the Halton HAC.2 Minus. The lower wings were donated to the Clark Cheetah G-AAJK. There were other minor changes.
It was used again for air racing, being entered in the 1928 and 1928 King’s Cup Races.
The aircraft was dismantled at Halton in 1930.
Powerplant: 1 × Bristol Cherub III, 32 hp (24 kW)
Wingspan: 28 ft 6 in (8.69 m)
Lower wingspan: 22 ft 0 in (6.71 m)
Length: 22 ft 0 in (6.71 m)
Crew: one
All Aero 