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What helicopter has the most rotor blades?

1

$begingroup$

I have seen 2 rotor blades up to many and wonder when does having more rotor blades become less efficient? What helicopter has the most rotor blades?

Related: Why don't helicopters prefer shorter rotors with more blades?

aircraft-design aerodynamics helicopter propeller

share|improve this question

edited 3 hours ago

Muze

asked 3 hours ago

MuzeMuze

1085

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Check out our Code of Conduct.

$endgroup$

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  If the blades are longer it has to spin slower to keep the tips from going supersonic. They are also heavier and harder to control
  $endgroup$
  – Ron Beyer
  3 hours ago
  

  
  
  
  


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  @RonBeyer do you think redundancy of having more blades could allow the helicopter to fly with damaged blades?
  $endgroup$
  – Muze
  3 hours ago
  
  

  
  
  
  


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  Unlikely. Chipped/mildly damaged blades can still fly, but once they fail structurally the entire rotor is unbalanced an no amount of extra blades is going to make it stabilize. It will shake itself apart as soon as it becomes unbalanced enough.
  $endgroup$
  – Ron Beyer
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  when does having more rotor blades become less efficient? -- any number more than one. The problem is if you need more lift then you need to use longer blades but if you cannot increase blade length due to structural issues and/or storage issues then you have no choice but to sacrifice efficiency for more lifting power. A single blade is ALWAYS the most efficient number of blades.
  $endgroup$
  – slebetman
  1 min ago
  

  
  
  
  

add a comment | 

1

$begingroup$

I have seen 2 rotor blades up to many and wonder when does having more rotor blades become less efficient? What helicopter has the most rotor blades?

Related: Why don't helicopters prefer shorter rotors with more blades?

aircraft-design aerodynamics helicopter propeller

share|improve this question

edited 3 hours ago

Muze

asked 3 hours ago

MuzeMuze

1085

New contributor

Muze is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  If the blades are longer it has to spin slower to keep the tips from going supersonic. They are also heavier and harder to control
  $endgroup$
  – Ron Beyer
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  @RonBeyer do you think redundancy of having more blades could allow the helicopter to fly with damaged blades?
  $endgroup$
  – Muze
  3 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  Unlikely. Chipped/mildly damaged blades can still fly, but once they fail structurally the entire rotor is unbalanced an no amount of extra blades is going to make it stabilize. It will shake itself apart as soon as it becomes unbalanced enough.
  $endgroup$
  – Ron Beyer
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  when does having more rotor blades become less efficient? -- any number more than one. The problem is if you need more lift then you need to use longer blades but if you cannot increase blade length due to structural issues and/or storage issues then you have no choice but to sacrifice efficiency for more lifting power. A single blade is ALWAYS the most efficient number of blades.
  $endgroup$
  – slebetman
  1 min ago
  

  
  
  
  

add a comment | 

$begingroup$

I have seen 2 rotor blades up to many and wonder when does having more rotor blades become less efficient? What helicopter has the most rotor blades?

Related: Why don't helicopters prefer shorter rotors with more blades?

aircraft-design aerodynamics helicopter propeller

share|improve this question

edited 3 hours ago

Muze

asked 3 hours ago

MuzeMuze

1085

New contributor

Muze is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

share|improve this question

edited 3 hours ago

Muze

asked 3 hours ago

MuzeMuze

1085

New contributor

Muze is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share|improve this question

edited 3 hours ago

Muze

asked 3 hours ago

MuzeMuze

1085

New contributor

Muze is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 3 hours ago

MuzeMuze

1085

New contributor

Muze is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 3 hours ago

MuzeMuze

1085

1 Answer
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2

$begingroup$

The most I've seen are 8 Mi-26. But the highest theoretical lifting efficiency is achieved with the fewest blades and experiments have been done with single blade rotors (with a counterweight - there were vibration problems that couldn't be resolved).

So in practical terms, the most lift for the least power is achieved with a 2 blade rotor, but the need to absorb more power with a limited desirable disc diameter forces you to add more blades (or you may want a smaller rotor with lots of blades for maneuverability or other reasons, but it's sub-optimal from a horsepower efficiency standpoint).

Put another way, a helicopter like the Mi-26 could probably achieve a fair bit more lifting power for its installed horsepower with a 2 blade rotor, but each blade would seemingly extend off into the next township.

share|improve this answer

answered 1 hour ago

John KJohn K

26k13880

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2

$begingroup$

The most I've seen are 8 Mi-26. But the highest theoretical lifting efficiency is achieved with the fewest blades and experiments have been done with single blade rotors (with a counterweight - there were vibration problems that couldn't be resolved).

So in practical terms, the most lift for the least power is achieved with a 2 blade rotor, but the need to absorb more power with a limited desirable disc diameter forces you to add more blades (or you may want a smaller rotor with lots of blades for maneuverability or other reasons, but it's sub-optimal from a horsepower efficiency standpoint).

Put another way, a helicopter like the Mi-26 could probably achieve a fair bit more lifting power for its installed horsepower with a 2 blade rotor, but each blade would seemingly extend off into the next township.

share|improve this answer

answered 1 hour ago

John KJohn K

26k13880

$endgroup$

add a comment | 

2

$begingroup$

The most I've seen are 8 Mi-26. But the highest theoretical lifting efficiency is achieved with the fewest blades and experiments have been done with single blade rotors (with a counterweight - there were vibration problems that couldn't be resolved).

So in practical terms, the most lift for the least power is achieved with a 2 blade rotor, but the need to absorb more power with a limited desirable disc diameter forces you to add more blades (or you may want a smaller rotor with lots of blades for maneuverability or other reasons, but it's sub-optimal from a horsepower efficiency standpoint).

Put another way, a helicopter like the Mi-26 could probably achieve a fair bit more lifting power for its installed horsepower with a 2 blade rotor, but each blade would seemingly extend off into the next township.

share|improve this answer

answered 1 hour ago

John KJohn K

26k13880

$endgroup$

add a comment | 

$begingroup$

The most I've seen are 8 Mi-26. But the highest theoretical lifting efficiency is achieved with the fewest blades and experiments have been done with single blade rotors (with a counterweight - there were vibration problems that couldn't be resolved).

So in practical terms, the most lift for the least power is achieved with a 2 blade rotor, but the need to absorb more power with a limited desirable disc diameter forces you to add more blades (or you may want a smaller rotor with lots of blades for maneuverability or other reasons, but it's sub-optimal from a horsepower efficiency standpoint).

Put another way, a helicopter like the Mi-26 could probably achieve a fair bit more lifting power for its installed horsepower with a 2 blade rotor, but each blade would seemingly extend off into the next township.

share|improve this answer

answered 1 hour ago

John KJohn K

26k13880

$endgroup$

share|improve this answer

answered 1 hour ago

John KJohn K

26k13880

answered 1 hour ago

John KJohn K

26k13880

answered 1 hour ago

John KJohn K

26k13880