What Purpose Of Rotor Head Dome In Helicopter?

[Super-Hornet]

Hi all

I see that some full size/real helicopter has a rotor head Dome similar to our R/C helicopter dome.

The question is, what is the purpose of those dome in real heli?

Is it act as gyroscopic stabilizer?
Or is it just a cover/umbrella to block rain/dirt from clogging up the rotor linkages?

Here are some of the pictures. (Sea King, Lynx, Super Stallion)

SH

[Xue]

My guess is...for covering up the very complicated looking rotor head...in another words for show lo...

[sookainian]

I think that things is to give more 'holding' on the blades

Mb is for giants to use their hands to slow down the blades like what we do on nitro

[sookainian]

anyway, i also think is for show too, just to make it look nicer

[ammo]

hhmmm..... aerodynamic benefits?

[skyblueblue]

more blades = less head speed ?

[mave]

as a cover for heat signature?

[Super-Hornet]

I posted the same question in other forum (one that I think they are more serious and more towards scale and quite of number of real helicopter pilots)

This is what some reply so far:
edward:
Eurocopter does that too. I think they are only used on helis with 3 blades and more.
It it said to help with aerodynamics. When you think about it, those huge american helis with tons of blades end up having enormous rotor hubs.
Maybe it also protects them against rain and sand while the helis are parked... Not sure.

bwellmaker:
Most of the time it just covers components around the rotor hub like blade fold accuators, pitch locks etc. On helis with heated blades, it covers the slip ring that powers the heated blades. On the 53 and 61 you can see a small cover in the center of the "bennie" that is a plexi cover to view the service level for the blade damper resv accumilator. The small holes on the 53 is access for servicing blade hindge pin resv on each blade.

copterdoctor:
i've always wondered about that too. helicopter express out of atl has a swirl on the top of their a-star and bell 407s that looks neat when turning.

SH

[Super-Hornet]

BTW skyblueblue.... More blades = more lifting power. It also indirectly link to lesser required RPM.

SH

[UH-1H]

Did u guys check the Russian helis? Do they have them too? If its cosmetics finishing, normally the US win in that department. But if the Hokum, Hind and Shark have them, then its something with aerodynamic in it..

[Helicopter]

Could it be for their radar? shaped like a radome. by placing it there, there should be less interferences.

[sookainian]

Could it be for their radar? shaped like a radome. by placing it there, there should be less interferences.

i think is to think for a radar to sit in and to small. Mb for the for this yes

[sookainian]

i think is to thin for a radar to sit in and to small*

[khatiban]

whatever it is i think manufacturers have reasons for every parts they mount onto their aircrafts. I think the reason given Super-Hornet sounds quite true.

The rotor hub assembly is quite vulnerable to damage. Any foreign objects that enters rotor hub might jam the whole mechanism and cause the heli to crash . So I guess that's when the dome cover become useful

[Super-Hornet]

Here are a few more other heli that has similar dome.

As for U.S. Heli with dome, not only U.S. heli has it.. Sea King, Lynx (both British Heli), Eurocopter also have it.