Firefly F1 performance and range:
Performance:
(Clean) Max speed:
284 mph (457 km/h) at sealevel,
273 mph (439 km/h) at 3,500 ft (1 O70 m),
319 mph (513km/h) at 17, 000 ft (5 180 m).
with two 90 Imp gal 409L drop tanks):
:257 mph 413 km/h) at sea level,
:266 mph (428 km/h) at 3,500 ft(1 070 m),
:288 mph (463 km/h) at 17,000 ft(5 180 m);
climb (normal climb rating):
(at 12,200 1b/5 534 k g) to 5,000 ft (1 525 m), 2:5 min
:to 10,000 ft (3 050 m), 5:75 min
:to 15000ft, 10:48min (Friedman)
:to 20000ft, 12.4min (RAE Testing at 11830lb from Mason, Secret Years)
range
: internal fuel with allowances for warmup, TO and climb) 774 miles(1245 km) at 233 mph (375 km/h)
: with two 45 Imp gal/204.5L drop tanks), 1,088 mls (1750 km) at 207 mph (33 km/h)
: with two 90 Imp gal/409L drop tanks), 1,364 mls 2 195 km) at 204 mph (328 km/h
From Wings of the Navy. Friedman states that the above performance included a load of 8 RPs.
By 1945 max combat boost was increased and max speed clean was ~325mph at 14k ft.