The A-20H was identical to the A-20G-45-DO, with the exception of being powered by the 1700 hp R-2600-29. This change in powerplant was made necessary by the discontinued production of the 1600 hp R-2600-23. The additional takeoff power offered by the -29 engine was especially welcome since the takeoff weight had increased from 21,500 pounds for the A-20C to 24,170 pounds for the A-20H. Aside from the engine change, there was no other noticeable change to distinguish the A-20H from the late A-20J.
A single A-20H (44-0466) was experimentally fitted with a tracked main undercarriage in an attempt to improve rough-field performance. However, since by this time in the war US forces had become very adept at repairing captured airfields and in building new ones, this innovation was found not to be necessary and no further experiments were carried out.
A total of 412 A-20Hs were built, all of them by Douglas-Santa Monica.
The A-20H-5-DO differed from the -1 in having provision for fragmentation bomb racks.
The A-20H-10-DO reverted to 1600 hp R-2600-23 engines. These were fitted with flame dampers, which would imply that they were intended for night intruder missions.
The A-20H-15-DO changed back to the R-2600-29s and introduced a heavier skin in the pilot's cockpit area.
A few A-20Hs were still on the USAF inventory when the A-for-attack designation category was eliminated in 1948. These aircraft became ZB-20H, the Z prefix indicating Obsolete.
44-1/8 Douglas A-20H-1-DO Havoc 44-10/25 Douglas A-20H-1-DO Havoc 44-26/65 Douglas A-20H-5-DO Havoc 44-199/328 Douglas A-20H-10-DO Havoc 44-407/536 Douglas A-20H-10-DO Havoc 44-619/706 Douglas A-20H-15-DO Havoc
Engines; Two 1600 hp Wright R-2600-29 Double Cyclone 14 cylinder twin-row
air-cooled radial engines equipped with two-speed superchargers.
Rated at 1700 hp for takeoff.
Performance: Maximum speed 333 mph at 15,600 feet. Cruising speed
269 mph. An altitude of 10,000 feet could be attained in 6.6 minutes.
Service ceiling 25,300 feet. Normal range 880 miles. Maximum ferry
range 2200 miles..
Dimensions: Wingspan 61 feet 4 inches, length 48 feet 0 inches,
height 17 feet 7 inches, wing area 465 square feet.
Weights: 16,842 pounds empty, 23,987 pounds gross. 27,000 pounds
Armament: Six forward-firing 0.50 Colt-Browning machine guns in the
nose with 350 rpg. Two 0.50-inch machine gun in dorsal power turret
with 400 rpg. One 0.50-inch machine gun in the ventral tunnel
position with 400 rounds. Maximum internal bomb load 2000 pounds in
split bomb bay plus 2000 pounds on four underwing hardpoints.