C172 Sound issue.

[Ron Attwood]

In that the engine sounds as if it was a record missing a groove every now and then. For younger viewers a record being a shellac 12" disc, a means of playing music on a gramophone circa 1950-70...Never mind, Lewis will know of what I speak.
So, motoring along happily, brrm brrm *click* brrm brrm *click*
My system or yours?

[Nick - A2A]

For younger viewers a record being a shellac 12" disc, a means of playing music on a gramophone circa 1950-70...

Gramophone eh Ron! Makes me think: have you given your ear trumpet a good shake out recently? (Sorry - I'm always cheekiest in the wee hours! )

To be honest, the only thing I've noticed is some slight high frequency noise at around the 1600 rpm mark. Sounds like something's 'squeaking' a bit and not a really a 'click' as such. At at rate, it goes away when I plug the headphones into the VC jack, so I don't worry about it.

Any chance you could have some form of cunning Accu-Sim damage: a chipped prop or something?

Cheers,
Nick

[Ron Attwood]

Any chance you could have some form of cunning Accu-Sim damage: a chipped prop or something?

Cheers,
Nick

That did go through my mind but as I hadn't flown the 172 for a while I did a thorough check before T/O. A clean bill of health.

I'll go listen to the .wav files, see if I pick up on anything.

EDIT: As you'd expect, nothing untoward in the sound package. Maybe if I changed the needle?

[Lewis - A2A]

Its not a mis-fire or anything from the engine then, or even a fouled plug having issues clearing?

thanks,
Lewis

[Nick - A2A]

Yes - could it be the engine misfiring if you're running the mixture a bit too lean or something? There's also an 'exhaust popping' sound which tends to occur with fairly hefty power reductions, but presumably that's not it...

[Ron Attwood]

Its not a mis-fire or anything from the engine then, or even a fouled plug having issues clearing?

thanks,
Lewis

Doesn't sound like it. I'll have another go soon (painting at the moment) and see if I'm still getting it.