Mast Bumping - Causes and Prevention

[Frazer]

Interesting video:

 

[maobingyishen]

Does BlackShark have this problem??

[slug88]

My guess is no, for two reasons:

 

1. the blades are shorter than in a typical single-main-rotor helicopter, and so you'd need much greater magnitude blade flapping in order to hit the mast

 

2. This follows from 1, the blades of the lower disk will intersect with the blades of the upper disk long before the lower disk is flapping enough to hit the mast, so mast bumping is a moot issue

[A.S]

cool movie:thumbup:

[AlphaOneSix]

Does BlackShark have this problem??

 

No, mast bumping is only possible on helicopters with a teetering rotor head. That is, a rotor with no flapping hinges and only two blades that are not allowed to flap independently. On a teetering rotor head, when one blade flaps up, the other is forced to flap down, since there is no hinge between the two sides.

 

On the Ka-50, the blades flap independently, so mast bumping is not possible.

[Frazer]

No, mast bumping is only possible on helicopters with a teetering rotor head. That is, a rotor with no flapping hinges and only two blades that are not allowed to flap independently. On a teetering rotor head, when one blade flaps up, the other is forced to flap down, since there is no hinge between the two sides.

 

On the Ka-50, the blades flap independently, so mast bumping is not possible.

 

Good to know :)

Still though, the Ka-50 also doesn't like 0 g flight. Ever noticed the "out of control" nose left+down reaction once you are in forward flight and quickly drop the collective combined with a slight cyclic push?

Not sure this has anything to do with this subject, though it is a dangerous habit of the Ka-50.

[AlphaOneSix]

Helicopters in general, whether they are susceptible to mast bumping or not, do not take kindly to low-G maneuvering.

 

For example, take the AH-64A, considered to be rather maneuverable...

 

Unloaded with a light fuel load, the max positive G-load is +3.5 and the max negative G-load is -0.5.

 

Loaded up near max weight, these limits are reduced to +2G max and +0.5G minimum.

[Hunt3r.j2]

Aircraft in general do NOT enjoy low g.

[Sharkster64]

Interesting, this is the same video that my ground school instructor showed my class to explain mast bumping and how to avoid it. Thanks for posting.:thumbup:

[norm]

Does that guy wake up talking like that?