Mast height?

[AV8RDOUG]

So, what are the pros/cons for a tall mast/rotor head vs. a much shorter one?.

I see the availability of longer blades (further from the tail and ground), but are there other benefits to a tall mast?

Thanks.

 

[Jean Claude]

Better damping of oscillations, due to angular delay of the rotor when it is subjected to a given roll or pitch rate

 

[wolfy]

Moves weight up higher which moves center of gravity higher to help align thrust line and COG.

wolfy

 

[Jean Claude]

With the mast higher, the damping moment is greater.

 

[AV8RDOUG]

Good stuff folks. Keep it coming... and thanks.

 

[Smack]

JM, I believe Jean will say that the "greater damping moment" means 'more stable', thus probably a bit less 'maneuverable'.

 

[j4flyer]

Is there a formula to determine what the proper mast height vs rotor diameter should be ?

 

[JETLAG03]

JM, I believe Jean will say that the "greater damping moment" means 'more stable', thus probably a bit less 'maneuverable'.

Does this mean that some some extent it actually works contrary to my imaginings, as I thought the higher the rotor head the greater the risk of topple over.

Another quicky, I have resin rotors 8.3m, and normally spin up the rotors to about 50rrpm before leaving the parking area for the runway thinking that a steady rotation helps reduce the "flapping" the blades experience on grass when static and enroute for the runway.

phil (de fer)

 

[Jazzenjohn]

A taller mast allows for a larger more efficient prop in most cases.