Undetermined. All helicopters have 2 rotors; usually a Main Rotor and a Tail Rotor. So, I assume you meant 2 Main Rotors of same diameter.
Boeing Ch-47 Chinook - One rotor mounted in the front over the cockpit and one rotor in the rear.
V-22 Osprey - Both rotors are mounted on engine pods mounted at the tips of the wings. The engines rotate from helicopter mode to airplane mode. This helicopter just went into operational service after years of development.
There are helicopters with no tail rotor. It has two rotors on top. One going clockwise the other going counter clockwise. Called Coaxial rotors or co-rotors are a pair of helicopter rotors mounted one above the other on concentric shafts. The military ones look like jets so even with jet engines. Very nasty looking helicopters.
They are much faster and can turn and maneuver much faster. You can look it up. Helicopters with Coaxial rotors. I do not mean the ones with the fan in the tail. These just have wings on the tail.
The other one is the NOTAR is the name of a helicopter anti-torque system which replaces the use of a tail rotor. Developed by McDonnell Douglas Helicopter Systems (through their acquisition of Hughes Helicopters), the name is an acronym derived from the phrase no tail rotor but uses air to keep the copter from spinning.
black hawk
There quite a few. Two of the most famous are the Boeing Vertol SeaKnight and the Boeing Chinook
Rotors, they are generally so-called (Props) applies to conventional propellers on conventonal aircraft, of course an autogyro or a Rotordyne has both propellers and Rotors but that is a special case.
Counter-propellers (proper name contra-rotating propellers) work by spinning in opposite directions. This cancels out torque in the same way as a helicopter uses rotors to cancel torque.
There was no bomber of any kind that had 8 propellers.
The name of the blood vessel which supplies glucose and oxygen to the heart muscle is an artery. Arteries carry blood away from the heart.
Helicopter Pilot.
I am wondering where was helicopter invented?
There has been no helicopter by that name
what is the meaning of Apache helicopter
Marine One for helicopter and Air Force One for aero
chopper?