There are thousands.
There are hundreds of different helicopters.
Yes, there were. Germany had some 27 models of aircraft classed as either helicopters or autogyros.
Planes have large wings, Helicopters have rotors
There are many different RC Helicopter models that can be purchased. Many different stores sell these helicopters. Toys R Us is one example of a store that sells them.
Air Hogs offers remote controlled toys. They include different models of helicopters, planes, rockets and land vehicles. They are available for different age groups as well as indoor and outdoor models. You can even use your smartphone to control the toy.
You can find information about military helicopters on the US Military website. It has a section specifically for helicopters of different varieties.
One can buy an indoor RC helicopter at Amazon. Amazon also sells other items and different models of indoor RC helicopters, varying at different prices.
There are many different makes and models of helicopters of many different sizes. The world's largest production helicopter is the Mil Mi-26, with an empty weight of about 62,000 lbs., and a max loaded weight of 123,450 lbs.
over 1,000
There are many different helicopters. Most small civilian helicopters may fly for about an hour, but large passenger or military helicopters can fly for 6 hours or more.
A. S. Braverman has written: 'Dinamika vertoleta' -- subject(s): Aerodynamics, Helicopters, Mathematical models
http://www.brentfordrc.co.uk/scripts/default.asp has a variety of different models of RC helicopters to choose from in the London area. They also have a store at 5 Albany Parade Highstreet Brentford Middlesex TW8 0JW