why do some helicopters have two rotors

If you are looking for commercial pilot license requirements, then you are on the right page. It contains how to get a pilot license. So Why Do Some Helicopters Have Two Rotors?

Tandem rotor helicopters have two large horizontal rotor assemblies mounted one in front of the other. Currently this configuration is mainly used for large cargo helicopters.

Single rotor helicopters need a mechanism to neutralize the yawing movement produced by the single large rotor. This is commonly accomplished by a tail rotor, coaxial rotors, and the NOTAR systems. Tandem rotor helicopters, however, use counter-rotating rotors, with each cancelling out the other’s torque. Therefore, all of the power from the engines can be used for lift, whereas a single rotor helicopter uses some of the engine power to counter the torque. An alternative is to mount two rotors in a coaxial configuration. The first successful tandem rotor helicopter was built by Nicolas Florine in 1927.

commercial pilot license requirements

Why Do Some Helicopters Have Two Rotors

Advantages of the tandem-rotor system are a larger center of gravity range, and good longitudinal stability. Disadvantages of the tandem-rotor system are a complex transmission, and the need for two large rotors.

The two rotors are linked by a transmission that ensures the rotors are synchronized and do not hit each other, even during an engine failure.

Tandem rotor designs achieve yaw by applying opposite left and right cyclic to each rotor, effectively pulling both ends of the helicopter in opposite directions. To achieve pitch, opposite collective is applied to each rotor; decreasing the lift produced at one end, while increasing lift at the opposite end, effectively tilting the helicopter forward or back.

Tandem rotor helicopters have the advantage of being able to hold more weight with shorter blades, since there are two sets. However, the rear rotor works in the aerodynamic shadow of the front rotor, which reduces its efficiency. This loss can be minimized by increasing the distance between the two rotor hubs, and by elevating one hub over the other. Tandem rotor helicopters tend to have a lower disk loading than single rotor helicopters.

Tandem rotor helicopters typically require less power to hover and achieve low speed flight as compared to single rotor helicopters. Both configurations typically require the same power to achieve high speed flight.

The main rotor provides lift and lateral control. It can allow the helicopter to fly in any direction.

The tail rotor controls the orientation of the helicopter (ie which way the nose points) and it counters the rotation of the main rotor.

Without the tail rotor, the body of the aircraft would start to spin in the opposite direction of the main rotor due to the torque on the main shaft.

The aircraft would be uncontrollable and lift would decrease as the rotation of the fuselage robbed power from the main rotor. The result is a crash.

  • Bell HSL (1953)
  • Boeing CH-47 Chinook (1961) – most-produced tandem-rotor helicopter (over 1,200 built)
  • Boeing Model 360 (1987)
  • Boeing Vertol 107-II (1958)
  • Boeing Vertol CH-46 Sea Knight (1960)
  • Boeing Vertol XCH-62 (1970s – not completed)
  • Boeing Vertol Model 234 (1981)
  • Bristol Belvedere (1958)
  • Bristol Type 173 (1952)
  • Chu CJC-3 (1952)
  • Filper Beta 200 (1966)
  • Filper Beta 400 (1967)
  • Filper Helicopter (1965)
  • HERC JOV-3 (1948)
  • Jovair Sedan 4A (1963)
  • McCulloch MC-4 (1951)
  • Piasecki H-16 (1953)
  • Piasecki H-21 (1949)
  • Piasecki H-25/HUP Retriever (1952)
  • Piasecki HRP Rescuer (1945)
  • Piasecki PV-14 (1948)
  • Rotorcraft XR-11 (1947)
  • Yakovlev Yak-24 (1952)

how to get a pilot license

Top 10 Luxury Helicopters in the World

Most people have heard of personal and charter jets, but luxury helicopters are the genuine gems. Not only are these aircraft comparatively less expensive, but helicopters can approach places that bulky jets can’t. Having a private or commercial helicopter is expedient, more environment friendly, and a symbol of status. Celebrities including Brad Pitt and Angelina Jolie and Donald Trump own a luxury helicopter, and this slot market has grown considerably in recent years due to demand from the rich.

They are well-appointed with all the newest technology, and interior seating marks that are designed in fine Italian leather upholstery.

Therefore the list of top 10 luxury helicopters is given below:

1. Augusta Westland AW119 Ke Koala:

luxury helicopters

The Koala is chiefly used by law enforcement, but it can easily provide accommodation to a group of corporate directors traveling on business. It has a VIP services quite adequately, with premium leather upholstery and seating for about 6 passengers and 2 operators. The Koala reaches a top speed of 166 mph (267 km/h) and a range of 618 miles (995 km). Price ranges from $1.8 to $3 million.

2. Eurocopter Hermès EC 135:

luxury helicopters

Though this brand of luxury helicopters is not suitable for long distant trips, is has a class apart built. The typical EC 135 will cost you a mere $4.2 million, but the one with the interior design from the best in class designer will cost you up to $6 million. The top speed is 178 mph, but the range is just 395 miles.

3. Augusta Westland AW109 Grand Versace VIP:

luxury helicopters

Augusta Westland teamed up with the Italian fashion house Versace to produce a super luxury interior for this fancier version of the AW109. The top speed is about 177 mph and a range of 599 miles. The mere difference is that all 599 of those miles will be more luxurious for the VIP passengers. Hence, will cost you $6.3 million price tag and the helicopter is fully covered in Versace leather, design and exterior.

4. Eurocopter Mercedes-Benz EC 145:

luxury helicopters

If you’re a Mercedes fan, now you can fly your preferred brand helicopter too. A regular EC 145 costs about $5.5 million, so the Mercedes version is going to cost anywhere around $7 million. But it’s totally worth it. No other Mercedes can go 153 mph while flying 17,000 feet above the ground. It has all the luxury of the famous German sports.

5. Eurocopter EC 175:

luxury helicopters

The EC 175 made its wonderful first appearance at the Paris Air Show in 2009. The chief feature of the EC 175 is that it can hold 16 passengers contentedly inside. The top speed reaches 178 mph (286 km/h), with a range of 345 miles (555 km). It costs whooping $7.9 million.

6. Eurocopter EC 155:

luxury helicopters

This is a luxurious chopper. Its top speed is an impressive 200 mph with a range of 533 miles. It can seat as many as 13 passengers; this spacious EC 155 aircraft will cost you $10 million.

7. Sikorsky S-76C:

luxury helicopters

The Sikorsky S-76C is more generally known as Black Hawk. The massive interior is large sufficient to fit up to a dozen passengers, but the seating occupies 4 passengers in Black Hawk model. It reaches a top speed of 178 mph (286 km/h) and has a range of 473 miles (761 km). It would cost you a $12.95 million.

8. Augusta Westland AW139:

luxury helicopters

The AW139 is appropriate for law enforcement, armed patrol and firefighters. It has a capacity to seat 8 passengers. The AW139 can reach an unbelievable top speed of 193 mph (310 km/h), with a range of 573 miles (922 km). It carries a beautiful interior costing you a hefty $14.5 million.

9. Bell 525 Relentless:

luxury helicopters

Like the Gulfstream 650 jet, the Bell 525 Relentless helicopter isn’t on the market currently. This chopper is going to cost $15 million. They predicted that the seating will be for 16, a top speed of 162 mph, and a range of 460 miles. This bright yellow Relentless with amazing seating will cost you a fortune.

10. Sikorsky S-92 VIP Configuration:

luxury helicopters

The S-92 can safely accommodate 9 passengers in its extensive interior cabin. The prices vary exponentially if you plan on decking the interiors with gold or crystal. The top speed of the S-92 is around 194 mph (312 km/h), with a range of 594 miles (956 km). The prices range from $17 million to $32 million.
Helicopter charter can be the most stress-free travel familiarity you will ever have. Which includes being able to travel outside of airports to reach vital meetings or even other flights in a different airport. Though rich class can afford these luxury helicopters, they are worth the investment.

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