Merlin Noise
 

Hi All,

The Merlin HM/HC 1,2 and 3 makes a distinctive 'swishing' noise - why? Been asked a number of times by students and still don't have a convincing answer.

Thanks!

BN

Maybe it's the rustling of brown envelopes? :eek:

It's a result of the blade tie down slots; AW installed cheap slots on the underside of the blade which act as a flute in the rotating air - hence the whistle. Other manufacturers use a bayonet fitting with a spring plunger which essentially seals the hole when not in use.

Thanks for replies - i had always thought it was blade-tether points but surely that would make a 5R swish as opposed to the distinctive 1R swish?

They can only afford one tie-down rope.

That's why the RAF gave them to the Navy - they always have odd bits of rope hanging around, they just call them funny names;)

The whistle is a safety feature. If you don't hear it on start-up, you left the blades tied-down 🤕

Some say it's the sound made by the accountant trying to justify the third engine.

Merlin, Merlin?


https://www.youtube.com/watch?v=P2nlGN6aS8g