I'd disagree it played a huge role from 39-45. It had a significant role from 39-42, with much of it being night bombing or support roles. The lack of defensive armament and speed made it an easy target for fighters. In the end, due to lack of vision by the LW, it was all they had and remained in production long after becoming obsolete.
I have to correct my self, it was active in until 1945 but production ended late 1944. By 1945, only small Kg units were using them as night here is all the variants it came in. The choices that AH have is the H-6, H-20/R-1 would be nice, but i think the "E" models where produced the most...but could be wrong on that.
* He 111 A-0: 10 aircraft built based on He 111 V3, two used for trials at Rechlin, rejected by Luftwaffe all 10 were sold to China".[23]
* He 111 B-0: Pre-production aircraft, similar to He 111 A-0, but with DB600Aa engines.
* He 111 B-1: Production aircraft as B-0, but with DB600C engines. Defensive armament consisted of a flexible Ikaria turret in the nose A Stand, a B Stand with one DL 15 revolving gun-mount and a C Stand with one MG 15.[23]
* He 111 B-2: As B-1, but with DB600GG engines, and extra radiators on either side of the engine nacelles under the wings. Later the DB 600Ga engines were added and the wing surface coolers withdrawn.[23]
* He 111 B-3: Modified B-1 for training purposes.[23]
* He 111 C-0: Six pre-production aircraft.
* He 111 D-0: Pre-production aircraft with DB600Ga engines.[23]
* He 111 D-1: Production aircraft, only a few built. Notable for the installation of the FuG X, or FuG 10, designed to operate over longer ranges. Auxiliary equipment contained direction finding Peil G V and FuBI radio blind landing aids.[28]
* He 111 E-0: Pre-production aircraft, similar to B-0, but with Jumo 211A-1 engines.
* He 111 E-1: Production aircraft with Jumo 211 A-1 powerplants. Prototypes were powered by Jume 210G as which replaced the original DB 600s.[28]
* He 111 E-2: Non production variant. No known variants built. Designed with Jumo 211 A-1s and A-3s.[28]
* He 111 E-3: Production bomber. Same design as E-2, but upgraded to standard Jumo 211A-3s.[28]
* He 111 E-4: Half of 2,000 kg (4,410 lb) bomb load carried externally.[28]
* He 111 E-5: Fitted with several internal auxiliary fuel tanks.[28]
* He 111 F-0: Pre-production aircraft similar to E-5, but with a new wing of simpler construction with a straight rather than curved taper, and Jumo 211A-1 engines.[33]
* He 111 F-1: Production bomber, 24 were exported to Turkey.[33]
* He 111 F-2: 20 were built. The F-2 was based on the F-1, differing only in installation of optimised wireless equipment.[33]
* He 111 F-3: Planned reconnaissance version. Bomb release equipment replaced with RB cameras. It was to have Jumo 211A-3 powerplants.[33]
* He 111 F-4: A small number of staff communications aircraft were built under this designation. Equipment was similar to the G-5.[33]
* He 111 F-5: The F-5 was not put into production. The already available on the P variant showed it to be superior.[33]
* He 111 G-0: Pre-production transportation aircraft built, featured new wing introduced on F-0.
* He 111 G-3: Also known as V14, fitted with BMW 132Dc radial engines.
* He 111 G-4: Also known as V16, fitted with DB600G engines.
* He 111 G-5: Four aircraft with DB600Ga engines built for export to Turkey.
* He 111 J-0: Pre-production torpedo bomber similar to F-4, but with DB600CG engines.[33]
* He 111 J-1: Production torpedo bomber, 90 built, but re-configured as a bomber.
* He 111 L: Alternative designation for the He 111G-3 civil transport aircraft.
* He 111 P-0: Pre-production aircraft featured new straight wing, new glazed nose, Db601Aa engines, and a ventral gondola for gunner (rather than "dust-bin" on previous models).[41]
* He 111 P-1: Production aircraft, fitted with three MG 15s as defensive armament.
* He 111 P-2: Had FuG 10 radio in place of FuG IIIaU. Defensive armament increased to five MG 15s.[41]
* He 111 P-3: Dual control trainer fitted with DB601A-1 powerplants.[41]
* He 111 P-4: Fitted with extra armour, three extra MG 15s, and provisions for two externally mounted bomber racks. Powerplants consisted of DB601A-1s. The internal bomb bay was replaced with a 835 L fuel tank and a 120 L oil tank.[41]
* He 111 P-5: The P-5 was a pilot trainer. Some 24 examples were built. The variant was powered by DB 601A engines.[41]
* He 111 P-6: Some of the P-6s were powered by the DB 601N engines. The Messerschmitt Bf 109 received these engines, as they had greater priority.[41]
* He 111 P-6/R2: Conversions later in war of surviving aircraft to glider tugs.
* He 111 P-7: Never built.[38]
* He 111 P-8: Its existence and production is in doubt.[38]
* He 111 P-9: It was intended for export to the Hungarian Air Force, by the project founder for lack of DB 601E engines. Only a small number were built, and were used in the Luftwaffe as towcraft.[38]
* He 111 H-0: Pre-production aircraft similar to P-2 but with Jumo 211A-1 engines.
* He 111 H-1: Production aircraft. Fitted with FuG IIIaU and later FuG 10 radio communications.
* He 111 H-2: This version was fitted with improved armament. Two D Stands (waist guns) in the fuselage giving the variant some five MG 15 Machine guns.
* He 111 H-3: Similar to H-2, but with Jumo 211A-3 engines. Like the H-2, five MG 15 machine guns were standard. One A Stand MG FF cannon could be installed in the nose and an MG 15 could be installed in the tail unit.
* He 111 H-4: Fitted with Jumo 211D engines, late in production changed to Jumo 211F engines, and two external bomb racks. Two PVC 1006L racks for carrying torpedoes could be added.".[67]
* He 111 H-5: Similar to H-4, all bombs carried externally, internal bomb bay replaced by fuel tank. The variant was to be a longer range torpedo bomber.[67]
* He 111 H-6: Torpedo bomber, could carry two LT F5b torpedoes externally, powered by Jumo 211F-1 engines, had six MG 15s and one MG FF cannon in forward gondola.[67]
* He 111 H-7: Designed as a night bomber. Similar to H-6, tail MG 17 removed, ventral gondola removed, and armoured plate added. Fitted with Kuto-Nase barrage balloon cable-cutters.[67]
* He 111 H-8: The H-8 was a rebuild of H-3 or H-5 aircraft, but with balloon cable-cutting fender. The H-8 was powered by Jumo 211D-1s.[67]
* He 111 H-8/R2: Conversion of H-8 into glider tugs, balloon cable-cutting equipment removed.
* He 111 H-9: Based on H-6, but with Kuto-Nase balloon cable-cutters.
* He 111 H-10: Similar to H-6, but with 20 mm MG/FF cannon in ventral gondola, and fitted with Kuto-Nase balloon cable-cutters. Powered by Jumo 211 A-1s or D-1s.[67]
* He 111 H-11: Had a fully-enclosed dorsal gun position and increased defensive armament and armour. The H-11 was fitted with Jumo 211 F-2s.[67]
* He 111 H-11/R1: As H-11, but with two 7.92 mm (.312 in) MG 81Z twin-gun units at beam positions.
* He 111 H-11/R2: As H-11, but converted to a glider tug.
* He 111 H-12: Modified to carry Hs 293A missiles, fitted with FuG 203b Kehl transmitter, and ventral gondola deleted.[67]
* He 111 H-14: Pathfinder, fitted with FuG FuMB4 Samos and FuG 16 radio equipment.[67]
* He 111 H-14/R1:Glider tug version.
* He 111 H-15: The H-15 was intended as a launch pad for the Blohm & Voss BV 246.[67]
* He 111 H-16: Fitted with Jumo 211F-2 engines and increased defensive armament of MG 131 machine guns, twin MG 81Zs, and a MG FF cannon.
* He 111 H-16/R1: As H-16, but with MG 131 in power-operated dorsal turret.
* He 111 H-16/R2: As H-16, but converted to a glider tug.
* He 111 H-16/R3: As H-16, modified as a pathfinder.
* He 111 H-18: Based on H-16/R3, was a pathfinder for night operations.
* He 111 H-20: Defensive armament similar to H-16, but some aircraft feature power-operated dorsal turrets.
* He 111 H-20/R1: Could carry 16 paratroopers, fitted with jump hatch.
* He 111 H-20/R2: Was a cargo carrier and glider tug.
* He 111 H-20/R3: Was a night bomber.
* He 111 H-20/R4: Could carry twenty 50 kg (110 lb) bombs.
* He 111 H-21: Based on the H-20/R3, but with Jumo 213E-1 engines.
* He 111 H-22: Re-designated and modified H-6, H-16, and H-21's used to air launch V-1 flying-bombs.
* He 111 H-23: Based on H-20/R1, but with Jumo 213A-1 engines.
* He 111 R: High altitude bomber project.
* He 111 U: A spurious designation applied for propaganda purposes to the Heinkel He 119 high-speed reconnaissance bomber design which set an FAI record in November 1937. True identity only becomes clear to the Allies after World War II.[68]
* He 111 Z-1: Two He 111 airframes coupled together by a fifth engine, used a glider tug for Messerschmitt Me 321.
* He 111 Z-2: Long-range bomber variant based on Z-1.
* He 111 Z-3: Long-range reconnaissance variant based on Z-1.