Data from: Mil's heavylift helicopters : Mi-6, Mi-10, V-12 and Mi-26 
izdeliye 50
The product or article number for the V-6 prototype.

V-6
(Zavod No.329 Moscow) First prototype series.

Mi-6
(NATO – Hook-A) Heavy-lift civil and military transport helicopter.

Mi-6A
Troopships and commercial transport helicopters built to a new baseline standard with improvements in reliability and new avionics.

Mi-6AYa
(NATO – Hook-D) OKB designation for the Mi-6VzPU and Mi-22 airborne command posts, with SLAR.

Mi-6APS
(PS - poiskovo-spasahtel'nyy - search and rescue) A limited number of search and rescue helicopters converted from Mi-6A standard aircraft.

Mi-6ATZ
(TZ - toplivoza-pravshchik - fuel tanker) Fuel transport helicopter variant of the Mi-6A.
Mi-6 Boorlak
(boorlak - barge hauler) Prototype ASW/MCM helicopters, used for research into ASW equipment when delays to the mission equipment forced cancellation.

Mi-6BUS
(NATO – Hook-C) (Also Mi-6AYa and Mi-22) airborne command post helicopter of 1975.

Mi-6L
(Also Mi-6LL: Letayushchaya laboratoriya) Flying laboratory variant with D-25VF engines used for flight improvements of the Mi-6 and testbed for the powerplant of the Mi-12.

Mi-6M
(M - morskoy - maritime) Anti-submarine variant armed with four aerial torpedoes and ASW rockets, and equipped with various experimental ASW systems.
First built in 1963 and modified in 1965 for the "Barge Hauler" program.

Mi-6M
(M - modifit-seerovannyy - modified) A projected redesign of the Mi-6 to carry 11 to 22 t (11,000 to 22,000 kg; 24,000 to 49,000 lb) over 800 km (500 mi), cancelled due to the limitations of the five-bladed rotor specified.

Mi-6P
(P - passazheerskiy - passenger) Passenger transport helicopter, with accommodation for 80 passengers.
One prototype was converted from a stock Mi-6.

Mi-6PP
(PP - postanovshchik pomekh - ECM aircraft) A prototype Counter-ELINT aircraft to protect air-defense radars from enemy ECM and/or ELINT activities .

Mi-6PR
(Protivodeystviya Radiorazvedke) Development in 1962 for jammer/electronic warfare variant.

Mi-6PRTBV
(podvizhnaya raketno-tekhnicheskaya baza vertlyotnovo tipa) A few modified as mobile missile maintenance technical bases and missile transporters.

Mi-6PS
(PS - poiskovo-spasahtel'nyy - search and rescue) Search and rescue (SAR) helicopter developed in 1966 for pick-up of the landed Vostok and Soyuz space modules.

Mi-6PSA
Alternative designation, used in some sources, for the Mi-6APS.

Mi-6PZh
(PZh - pozharnyy - fire fighting) Fire fighting variant, with a 12,000 l (2,639.63 imp gal; 3,170.06 US gal) tank in the cabin and six 1,500 l (329.95 imp gal; 396.26 US gal) bags suspended from the fuselage.
The sole prototype crashed in France fighting a fire, soon after display at the 27th Paris Air Show.

Mi-6PZh2
A second firefighting helicopter prototype and several conversions with a steerable water cannon in the nose.

Mi-6R
(R - Retranslyator - ) Specialised radio communications relay variant developed in 1974, prototype conversions only.

Mi-6RVK
(RVK - raketno-vertolyotny kompleks - heliborne missile system) Tested in 1965 loaded with 9K53, 9K73, 9M21 Loona-MV or 8K114 mobile missile systems.

Mi-6S
Medical evacuation helicopter, which can carry 41 litters.

Mi-6T
(NATO – Hook-A) Military transport helicopter, which can seat up to 70 people on tip-up seats along the cabin sides, with additional seat along the center-line.

Mi-6TP
Convertible freight/passenger helicopter.

Mi-6TZ
(TZ - toplivoza-pravshchik - fuel tanker) Fuel transport helicopter to refuel vehicles and helicopters on the ground.

Mi-6TZ-SV
(TZ-SV - toplivoza-pravshchik - sookhoputnyye voyska - fuel tanker-ground forces) Fuel transport helicopter to refuel vehicles on the ground.

Mi-6VR
(VR - Vodoley - Aquarius) A water spraying research helicopter to test helicopter anti-icing systems.

Mi-6VKP
(NATO – Hook-B) (VKP - vozdooshnnyy poonkt - airborne command post) Command post transport helicopter to deploy comms and war room on the ground, not usable in flight.

Mi-6VUS 
(NATO – Hook-D) airborne command post with SLAR.

Mi-6VzPU
(NATO – Hook-D) Servi
Data from: Mil's heavylift helicopters : Mi-6, Mi-10, V-12 and Mi-26 
izdeliye 50
The product or article number for the V-6 prototype.
V-6
(Zavod No.329 Moscow) First prototype series.
Mi-6
(NATO – Hook-A) Heavy-lift civil and military transport helicopter.
Mi-6A
Troopships and commercial transport helicopters built to a new baseline standard with improvements in reliability and new avionics.
Mi-6AYa
(NATO – Hook-D) OKB designation for the Mi-6VzPU and Mi-22 airborne command posts, with SLAR.
Mi-6APS
(PS - poiskovo-spasahtel'nyy - search and rescue) A limited number of search and rescue helicopters converted from Mi-6A standard aircraft.
Mi-6ATZ
(TZ - toplivoza-pravshchik - fuel tanker) Fuel transport helicopter variant of the Mi-6A.
Mi-6 Boorlak
(boorlak - barge hauler) Prototype ASW/MCM helicopters, used for research into ASW equipment when delays to the mission equipment forced cancellation.
Mi-6BUS
(NATO – Hook-C) (Also Mi-6AYa and Mi-22) airborne command post helicopter of 1975.
Mi-6L
(Also Mi-6LL: Letayushchaya laboratoriya) Flying laboratory variant with D-25VF engines used for flight improvements of the Mi-6 and testbed for the powerplant of the Mi-12.
Mi-6M
(M - morskoy - maritime) Anti-submarine variant armed with four aerial torpedoes and ASW rockets, and equipped with various experimental ASW systems. First built in 1963 and modified in 1965 for the "Barge Hauler" program.
Mi-6M
(M - modifit-seerovannyy - modified) A projected redesign of the Mi-6 to carry 11 to 22 t (11,000 to 22,000 kg; 24,000 to 49,000 lb) over 800 km (500 mi), cancelled due to the limitations of the five-bladed rotor specified.
Mi-6P
(P - passazheerskiy - passenger) Passenger transport helicopter, with accommodation for 80 passengers. One prototype was converted from a stock Mi-6.
Mi-6PP
(PP - postanovshchik pomekh - ECM aircraft) A prototype Counter-ELINT aircraft to protect air-defense radars from enemy ECM and/or ELINT activities .
Mi-6PR
(Protivodeystviya Radiorazvedke) Development in 1962 for jammer/electronic warfare variant.
Mi-6PRTBV
(podvizhnaya raketno-tekhnicheskaya baza vertlyotnovo tipa) A few modified as mobile missile maintenance technical bases and missile transporters.
Mi-6PS
(PS - poiskovo-spasahtel'nyy - search and rescue) Search and rescue (SAR) helicopter developed in 1966 for pick-up of the landed Vostok and Soyuz space modules.
Mi-6PSA
Alternative designation, used in some sources, for the Mi-6APS.
Mi-6PZh
(PZh - pozharnyy - fire fighting) Fire fighting variant, with a 12,000 l (2,639.63 imp gal; 3,170.06 US gal) tank in the cabin and six 1,500 l (329.95 imp gal; 396.26 US gal) bags suspended from the fuselage. The sole prototype crashed in France fighting a fire, soon after display at the 27th Paris Air Show.
Mi-6PZh2
A second firefighting helicopter prototype and several conversions with a steerable water cannon in the nose.
Mi-6R
(R - Retranslyator - ) Specialised radio communications relay variant developed in 1974, prototype conversions only.
Mi-6RVK
(RVK - raketno-vertolyotny kompleks - heliborne missile system) Tested in 1965 loaded with 9K53, 9K73, 9M21 Loona-MV or 8K114 mobile missile systems.
Mi-6S
Medical evacuation helicopter, which can carry 41 litters.
Mi-6T
(NATO – Hook-A) Military transport helicopter, which can seat up to 70 people on tip-up seats along the cabin sides, with additional seat along the center-line.
Mi-6TP
Convertible freight/passenger helicopter.
Mi-6TZ
(TZ - toplivoza-pravshchik - fuel tanker) Fuel transport helicopter to refuel vehicles and helicopters on the ground.
Mi-6TZ-SV
(TZ-SV - toplivoza-pravshchik - sookhoputnyye voyska - fuel tanker-ground forces) Fuel transport helicopter to refuel vehicles on the ground.
Mi-6VR
(VR - Vodoley - Aquarius) A water spraying research helicopter to test helicopter anti-icing systems.
Mi-6VKP
(NATO – Hook-B) (VKP - vozdooshnnyy poonkt - airborne command post) Command post transport helicopter to deploy comms and war room on the ground, not usable in flight.
Mi-6VUS 
(NATO – Hook-D) airborne command post with SLAR.
Mi-6VzPU
(NATO – Hook-D) Servi
Mil Mi-6