Helicopters are an incredible feat of engineering that utilize one or more horizontally spinning rotors to generate enough lift for vertical takeoff and landing. Their unique capabilities, from hovering in place to maneuvering in tight spaces, opened up a world of new possibilities in aviation.
Since the first helicopters took flight in the early 20th century, they have evolved into a remarkably diverse range of types and configurations. Over 45,000 helicopters are flying today, serving countless roles across military, civilian, and commercial sectors.
In this comprehensive guide, we will take a closer look at over 30 different types of helicopters. From light helicopters all the way up to heavy lift cargo choppers, we‘ll uncover what makes each design unique and their capabilities.
A Brief History of Helicopters
The origin of vertical flight technology dates back to ancient China where simple rotor toys were among the first vertical lift devices. Leonardo da Vinci sketched helicopter designs with articulated rotors as early as the 15th century. But it wasn‘t until the early 1900s that practical helicopters finally took flight.
In 1907, French engineer Paul Cornu built and flew the first manned helicopter able to hover for almost a minute. This experimental helicopter had two large perpendicular rotors driven by a 24 hp engine.
In the 1920s and 1930s, pioneers like Spanish engineer Juan de la Cierva developed the first successful autogyros. Though not true helicopters, these innovative rotorcraft could generate lift from an unpowered spinning rotor.
By the late 1930s, helicopters like the German Focke-Wulf Fw 61 demonstrated much improved controllability and reliability. Coaxial rotor configurations also emerged, epitomized by experimental Soviet helicopters created by Igor Sikorsky and Nicholai Kamov.
During World War II, Sikorsky‘s VS-300 became the first practical single rotor helicopter design. Its success paved the way for widespread adoption of the single main + tail rotor configuration used on most helicopters today. By the early 1950s, helicopter technology had progressed enough for large scale military and civilian applications.
Today, annual global civil helicopter deliveries exceed >$5 billion revenue across over 180 models. Helicopters serve countless niches where their unique capabilities empower vertical flight.
Now let‘s dive deeper and survey some of the most common and specialized helicopter types flying today!
Single Main Rotor Helicopters
The single main rotor design is the most prevalent modern helicopter configuration. As the name suggests, it consists of a single large rotor providing lift and propulsion mounted above the fuselage. These helicopters also have a smaller tail rotor that counters the torque effect of the main rotor.
Single rotor helicopters make up over half of rotorcraft today. They balance simplicity and reliability with excellent versatility.
Popular single main rotor helicopter models include:
- Robinson R44 – Over 6,000 produced. Widely used for private and commercial operations.
- Airbus H145 – Over 1400 delivered. Multi-purpose twin engine helicopter.
- Bell 206 – Over 7,500 built. Popular light helicopter for utility and observation roles.
- Leonardo AW119 – Over 380 produced. Light multi-purpose helicopter.
The single main rotor design lends itself to a variety of applications:
- Police and law enforcement
- Electronic news gathering
- Sightseeing tours
- Offshore oil transport
- Ranching and agriculture
- Air ambulance / EMS
- Aerial surveying
And many more! Their simplicity, stability, and reliability make single rotor helicopters a jack of all trades across civilian and commercial aviation.
Tandem Rotor Helicopters
Tandem rotor helicopters have two large horizontal rotors arranged fore and aft on the fuselage. The rotors turn in opposite directions to balance each other‘s torque effects.
Examples of tandem rotor helicopters include:
- Boeing CH-47 Chinook – Over 1200 built. Heavy lift military transport.
- Kaman K-MAX – Single passenger heavy lift helicopter. optimized for external cargo load operations.
- Piasecki H-21 – Nicknamed "Flying Banana" due to enclosed fuselage. US Army workhorse in the 1950s.
Tandem rotor helicopters trace their lineage to designs by Nikolai Kamov and Frank Piasecki in the 1940s. By using two large rotors instead of one main rotor, tandem rotor helicopters can lift substantially heavier loads. The rear rotor also counteracts the torque of the front rotor, eliminating the need for a separate tail rotor.
Some drawbacks of the tandem design include a larger frontal profile and more complex transmission systems to drive multiple rotors. But their excellent lifting capabilities make tandem rotor helicopters well-suited for demanding cargo transportation duties where heavy lift performance is paramount.
Compound Helicopters
Compound helicopters supplement traditional rotor lift with additional propulsive mechanisms. These typically include stub wings and propellers or ducted fans integrated into the airframe.
Examples of compound helicopters include:
- Sikorsky X2 – Demonstrator that achieved 260 knots in 2010 paving the way for high speed helicopters.
- Airbus Racer – Precursor to the Eurocopter X3 which aims to fly up to 250 knots.
- Lockheed AH-56 Cheyenne – Advanced compound attack helicopter prototype designed in the 1960s with a pusher prop and 267 knots top speed.
By offloading the main rotors in forward flight, compound helicopters can achieve significantly higher speeds compared to conventional helicopters. The additional propulsive mechanisms also increase efficiency and range.
For example, Sikorsky‘s X2 technology demonstrator achieved sustained speeds over 250 knots – up to 100 knots faster than a conventional helicopter. Compound helicopter designs continue to push speed and performance boundaries for helicopter applications requiring higher cruise speeds and dash capabilities.
Tiltrotor Helicopters
Tiltrotor aircraft have rotors that can change orientation between vertical and horizontal configurations. For vertical takeoff and landing, the rotors stay in helicopter mode. Once airborne, the rotors tilt forward to transition into a turboprop airplane.
The flagship tiltrotor aircraft is the:
- Bell-Boeing V-22 Osprey – Over 360 delivered to the US Marine Corps and Air Force.
By combining helicopter-like VTOL capability with excellent fixed wing speed and range, tiltrotors offer revolutionary versatility. Their performance fills a useful niche between helicopters and airplanes.
The V-22‘s 250 knot cruising speed and 2500 nm range far exceed any conventional helicopter. Short takeoff rolls also enable the V-22 to operate from smaller landing zones than fixed wing transports. These attributes make tiltrotors ideal for amphibious operations, long range troop transport, and special operations.
More advanced tiltrotor designs are also now in development, including:
- Bell V-280 Valor – Next generation tiltrotor that aims to reach 280 knots speeds.
- Leonardo Next Generation Civil Tiltrotor – Larger 120 passenger civil tiltrotor concept.
Coaxial Helicopters
Coaxial helicopters have two main rotors positioned one above the other and rotating in opposite directions around the same mast. This cancels out torque effects, eliminating the need for a tail rotor.
Examples of notable coaxial helicopters include:
- Kamov Ka-50 Hokum – Russian attack helicopter operated since the 1990s.
- Sikorsky X2 – Helicopter that achieved 260 knots using coaxial rotors and a pusher prop.
- Kamov Ka-27 – Maritime utility helicopter with rear loading ramp operated by Russia and other nations.
The earliest coaxial helicopter designs emerged in the 1940s from pioneering work by Soviet engineers Igor Sikorsky and Nikolai Kamov. By concentrating rotor torque in one axis, coaxial helicopters avoid energy losses and eliminate the need for a tail rotor.
This provides a more stable and compact helicopter with increased lift potential. However, coordinating two counter-rotating rotor systems requires complex mechanics. The narrow fuselage can also limit internal space compared to single rotor designs.
Today, coaxial helicopters occupy mostly military niches benefitting from their agility, compact size, and lack of a vulnerable tail rotor.
Intermeshing Rotor Helicopters
Intermeshing rotor helicopters have two main rotors positioned closely together at the top of the fuselage. The rotors are timed and angled to interlock without colliding as they counter rotate.
Intermeshing rotor examples include:
- Kaman K-MAX – Single seat heavy lift helicopter optimized for external cargo loads.
- Fairey Rotodyne – Early compound gyroplane with intermeshing rotors flown in the 1950s.
By eliminating the overlap losses between spaced rotor blades, intermeshing rotor helicopters are among the most aerodynamically efficient rotorcraft. This gives them excellent lifting capabilities but necessitates precision rotor timing.
Intermeshing rotor designs can lift useful loads equal to their empty weight. The K-MAX cargo helicopter can lift over 6000 lbs, more than the helicopter‘s empty weight. This helps maximize payload capacity for demanding heavy lift missions.
Electric Helicopters
Electric helicopters replace conventional turboshaft engines with electric motors powered by onboard batteries. They produce very low noise and have zero emissions during flight.
Emerging electric helicopter models include:
- Volocopter – Innovative 18 rotor eVTOL positioning for urban air taxi services.
- EHang 216 – Autonomous air taxi with 16 electric rotors and cruising speed of 80 knots.
- Joby Aviation – eVTOL with 12 tilting rotors and 322 km range. One of the first to be FAA certified.
Many companies are pursuing eVTOL aircraft for new Urban Air Mobility (UAM) transportation services. Most of these next-gen vehicles rely on electric distributed propulsion concepts.
By using many smaller electrically driven rotors, eVTOL aircraft can be both more efficient and quieter than conventional helicopters. This enables eco-friendly low noise operations in urban city centers.
NASA also successfully demonstrated the Maxwell X57 electric propulsion aircraft by retrofitting a Tecnam P2006T twin engine plane with 14 electric motors. The distributed electric propulsion system increased the aircraft‘s efficiency by nearly 5X.
As battery densities continue improving, electric propulsion will open up new possibilities in aviation for helicopters and other eVTOL aircraft.
Special Mission Helicopters
Helicopters excel at niche applications by tailoring them to particular missions. Here are some examples of specialized helicopter types and their roles:
Air Ambulance Helicopters
Air ambulances like the Bell 429 or Airbus H145 rapidly transport patients requiring urgent medical care. They are equipped with stretchers, medical supplies and life support systems to bring critical care facilities directly to the scene.
Firefighting Helicopters
Helicopters like the Mil Mi-8 and Sikorsky S-64 Air Crane carry large 3600+ liter water tanks or buckets to combat wildfires. Their ability to accurately drop water across vast and rugged areas is invaluable for quick containment of forest and brush fires.
Search and Rescue Helicopters
Dedicated SAR helicopters like the Sikorsky S-92 and Leonardo AW109 excel at locating and retrieving people in even the most harsh conditions. They utilize radars, FLIR cameras, hoists and cargo hooks to retrieve distressed people day or night, far from bases.
Police Helicopters
Police helicopters provide aerial surveillance and support during critical incidents and pursuits. Models like the Bell 206 and Airbus H120 increase situational awareness and help coordinate ground units across a wide area.
Electronic News Gathering Helicopters
ENG helicopters such as the Bell 206 JetRanger and Airbus AS350 B2/B3 "Starship" enable journalists to capture aerial footage of news events as they unfold. Their stability and aerial visibility helps obtain compelling videos and images.
Offshore Helicopters
Offshore helicopters like the Sikorsky S-92 transport crews to and from installations like oil rigs situated far from shore. They enable quick crew changes and deliver supplies to remote offshore platforms.
Tourism Helicopters
Operators like Airbus H130s and Bell 206Bs tailored for scenic tours provide passengers breathtaking views. Tour helicopters fly smoothly and slowly for ideal sightseeing with doors removed when permitted.
Geological Survey Helicopters
Helicopters can access extremely remote survey sites with geophysical instrumentation. They conduct aerial magnetic surveys, photography, and rapidly transport researchers on expeditions.
Agriculture Spraying Helicopters
Ag helicopters allow precise crop dusting and spraying. By flying low and slow, helicopters like the Bell 47 and Hiller 12E can accurately apply fertilizers, herbicides and pesticides with minimal drift.
Heavy Lift Helicopters
Tandem rotor CH-47 Chinooks and S-64 Skycranes haul 20,000 lb+ external loads. Heavy lift helicopters transport vehicles, generators, and even prefabricated homes or oil rig modules to remote areas.
Unmanned Aerial Systems
Unmanned helicopters and rotorcraft conduct reconnaissance, cargo delivery, HAZMAT handling, infrastructure monitoring and other missions too dangerous or dull for human pilots.
Military Helicopters Types
Helicopters fill diverse combat and logistics roles across the armed forces. Military helicopters types include:
Attack Helicopters
Heavily armed gunships like the Boeing AH-64 Apache provide close air support. Its Hellfire missiles and 30mm cannon destroy tanks and engage ground targets. Attack helicopters also escort transport formations and reconnaissance missions.
Transport Helicopters
Heavy lift transport rotorcraft like the Sikorsky CH-53 Sea Stallion move troops, vehicles and supplies from ships to frontline areas. The twin turbine CH-47 Chinook can carry up to 25,000 lbs of cargo internally or slung externally. Transports perform the critical role of airdropping and airmobile insertions of soldiers and armaments.
Maritime Helicopters
Maritime helicopters operate from ships and coasts. The Sikorsky SH-60 Seahawk conducts anti-submarine and anti-ship warfare with torpedoes, depth charges and missiles. It also provides search and rescue, vertical replenishment, and medical evacuation capabilities at sea.
Multi-Role Helicopters
Multi-role helicopters like the Mil Mi-17 transport personnel and cargo while also capable of attack missions. The Bell UH-1 "Huey" saw extensive service as a gunship, troop carrier, and MEDEVAC helicopter during Vietnam and after.
Training Helicopters
Ab initio trainees learn flying basics on helicopters like the Bell 206B JetRanger. Multi-engine turboshaft trainers like the Bell 412 also prepare pilots before transitioning them to frontline types.
Simulators and computer based training are increasingly supplementing aircraft to train military helicopter pilots efficiently. Training in actual helicopters remains crucial however for real world procedural experience.
Final Thoughts
We‘ve spanned over 30 types ranging from light helicopters up to heavy lifting cargo rotorcraft. Helicopters continue evolving rapidly with new eVTOL and autonomy concepts.
Electric urban mobility vehicles promise cleaner, quieter rotorcraft operations. eVTOLs also avoid issues helicopters face reaching high altitudes and high speeds.
Tiltrotors combine excellent speed and range expanding how rotorcraft support missions. Advanced attack helicopters field new armaments and stealth technologies as well.
Even after over 100 years of rotary-wing flight, helicopters remain one of aviation‘s most versatile innovations. Their unique capabilities will ensure helicopters keep playing vital roles across both civilian and military aviation for decades to come.
