What would cause this noise on start up?

[cptjim]

What component would cause the sound that you hear on initial start up? I fly turbines but have never heard that before. It sounds to me like a combustion noise?

Thanks

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I tried to embed the videos but I guess I'm too stoopid!! :ugh:

[cptjim]

At the 14-21 sec mark and 25-27 sec mark in the first video.

[2F1B]

Its the fuel igniting on the first engine on the first one, then the same on the second engine on the second one....... Perfectly normal

[cptjim]

Thanks for the replies, I had just never heard it that loud on a 902 before.

[chopper_doctor]

Dylithium crystals, worn out.

[Takan Inchovit]

Sounds a lot like one or two of my colleagues about 1.5 hrs after lunch.

[Bertie Thruster]

Flew LNAA from new (2000) for 12 years. The P+W 206 engines always made that noise on start up.

[Gazzer1uk]

That's interesting, when the Westland Scout used to start up it made a similar sound, but is obviously only a single engine.... I always thought it was the point immediately before the engine thrust hit enough power to start rotating the blades, and was the deflection of the thrust?

It would not be the first time I am wrong and I am not a pilot and this is going back some years, but to me it was one of the hallmark noises of the Scout, nice to hear it on a modern bird though.