Just has to be the Merlin, but not just the one wasted in a ‘woosy’ fighter - but 4 in the Lanc! Can’t beat that sound of the surge in power as you go from 1900 up to 2400rpm as you run in!

Oh, and as for impressive sounding starting - a pair of Avpin-started Avons!

I nearly fouled my breeches at Chivenor one airshow when 40 Hunters started at the same time. Awsome!

The drone of Ivchenko-engined IL-18s anywhere you went in Eastern Europe till the Wall came down; there always seemed to be one within earshot.

India Bombay 1976
 

Arriving from Hong Kong and disembarking down the stairs en route to the awaiting bus there was very distinctive jet staring a take off run. As it was the usual midnight arrival and very dark I could not make out the aircraft as it sped along the runway. I could see however what appeared to be flames (maybe afterburners I though) , and as it lifted off the flames increased in intensity.
I stood mesmerized in horror.
The pilots struggled to return to the airport before complete control was lost and the plane nosed over and crashed just outside the airport.
Only then did I see the outline of the Caravelle.
The sound of the engines and memory of that tragic flight ,will live with me forever.
Indian Airlines Flight 171 12th October 1976
Kevin

The intake howl from the four Bristol (!) Olympuses in the Vulcan always gets to me.

The Merlin as already mentioned a few times. I was standing outside a warehouse near Hucknall in about 1990 as Rolls-Royce's Mk.XIV Spitfire flew over. 'Nothing like the sound of a Merlin' said the bloke standing next to me.

I couldn't say I could identify a Merlin from a Griffon heard singly, but I do prefer the Griffon growl and seriously lumpy idle.

It’s funny how they stay with you.
- Hunter F6 blue note,
- L1049 Constellation with those R3350’s just above idle on the ground,
- ‘Rare Bear’, modified Bearcat with R3350, coming round that last pylon doing 500 knots and the sound of that big 3 bladder,
- Four x CF6-80B2’s, or, four x PW4063’s on take off from the cockpit.....alas, no more..... retired 10 years now.....:sad:

JO.

In modern times, i vote the RB211 as being pretty distinctive on start up and perhaps more so the MOOO from the GE90 on start up.

PT-22, Kinner R5 from the cockpit. You get to hear one exhaust out of 5..

Most jet engines don’t do much for me - my instinctive answer would always be the Merlin.
The screech of the Dart brought back happy childhood memories, but the sound that does it for me.....

4 Allison T56 A-15s under the wing of dear old Albert......but I’m biased!

Beaver - P & W R985

Two for me, firstly the SRN 4 Hovercraft and secondly the VC10's Conway note at idle in the flare followed by the roar of revers thrust.

Merlins, Griffons, Darts, most of us remembering the sounds of our youth.
Still, hard to believe today’s generation will one day be reminiscing about the CFM56.

The North American Harvard, T6 Texan, had a very distinctive sound. Or was that the propellor?

P&W R2800 (C118 / DC6) no doubt, but maybe I am one of the disappearing generation…

Lancman - the prop, it was - tips went supersonic.

Distinctive, but not charismatic - some of the Britten Norman Trislanders operated by Aurigny in the Channel Islands had two-bladed props on all three engines, but some had the three-bladed prop on the wing mounted engines and two blades on the tail mounted engine. Those ones had a very strange sound as there was still some kind of beat even when the engine speeds were synchronised.

The C-5A had a pretty distinctive howl on take off or when reverse thrust selected - those TF-39s...

The Harvard was banned from Biggin for a bit, but there is one based there again now - another aircraft I occasionally hear in the circuit from five or six miles away when the wind is right.

Given the amount that its' sound is used as a 'catch all' jet fighter engine sound by 'foley' sound engineers in film and TV, it has to be the RR/Bristol Pegasus.

Personally, it is a close run thing between the RR Griffon and Merlin. The Griffon just shades it; it just sounds like raw power, especially in a late mark Spitfire. The noise as it comes down off a steep turn, with the supercharger whine is something to behold.

A special mention must go to the Allison T56-A, but that is more to do with it being evocative of where I live (and grew up...)

1-11 Speys on start, yes, but remember that funny little high-pitched claim of approval they gave out as the ignition kicked in ?

OATS, Kidlington, one of many Cadets walking across the apron for 'running change' but some spitfire bod on the way to a display must have spotted us & gave an impromptu low level pass. Appeared over the trees, steepturned in the climb away & left us all standing, quite still, with hundred percent smiles. Nearly walked into a running prop !

There was a post on WIX some years ago where somebody who had flown all three was asked for a comparison between the Allison, Merlin and Griffon.

Paraphrasing quite a lot, he said the Allison was a very smooth engine, the Merlin was obviously in a much higher state of tune, and the Griffon just sounded like it wanted to kill somebody.