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What is rotor disc area?
It is determined by dividing the total helicopter weight by the rotor disc area, which is the area swept by the blades of a rotor. Disc area can be found by using the span of one rotor blade as the radius of a circle and then determining the area the blades encompass during a complete rotation.
Are rotor resurfacing worth it?
Some vehicle manufacturers even require that you replace your rotors rather than resurface them. Otherwise, most industry experts suggest that you should replace them every 30-70K miles. In any case, if the rotors are beyond resurfacing, replacement is your only option.
How much are disc rotors?
The average cost of having your front brake pads and disc rotors replaced starts around $300 and can increase to $700+, depending on the type of vehicle and the brake components used.
How does relief of rotor disk loading enable higher speed?
Relief of rotor disk loading enables higher speed, by either: A smaller rotor disk tilted forward more, in combination with a fixed wing, makes the rotor function more like a propeller and allow for a greater forward speed. Using counter-rotating dual rotors allows for shorter blades per rotor.
Why are longer rotors better for a helicopter?
My understanding of helicopters is that, despite theoretically increasing efficiency, longer blades are worse in practice than short ones in every respect (except, perhaps, cost): Longer blades are more prone to vibration and resonance dynamics, if for no reason other than that their rigidity is reduced by length, holding all else constant.
What is the figure of Merit of a helicopter?
Figure of Merit (F.M.) – measure of efficiency of a hovering rotor. The geometry of the rotor basically determines the figure of merit. Things like, tip speed (function of rotor rpm and rotor radius), blade area, number of blades, taper, tip shape, twist, and airfoil section.
Why do you need so many blades on a helicopter?
The blades, like wings, affect air to a significant distance above and below them, so you don’t need many blades to use all air within the rotor area. But no matter how many blades you add, they will still only affect the air within the rotor area, so the efficiency won’t change much.