What are the different types of helicopters?

All US helicopters are advanced modernized versions (or descendents) of the Vietnam War era choppers:

1. CH-53 Sea Stallion (CH=Cargo helicopter)

2. AH-1 Cobra (AH=Attack Helicopter)

3. UH-1 Iroquois (the Huey/UH=Utility Helicopter)

4. HH Jolly Green Giants (HH=Heavy left Helicopter)

5. OH-58 Kiowa (Observation Helicopter/jet ranger)

6. OH-6 Cayuse (Observation Helicopter/this bird actually was designed to replace the US Army's O-1 Bird Dog artillery observation airplane; used for the last time in Vietnam).