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Cheers - AE

Monday, 29 March 2010

I'm going to stop moaning about the RAAF.

I was going to post this yesterday but the need to blog on some anti-smoking, pro-nanny bastard meant I didn't have time.

On Saturday I said this:
And tell the fucking RAAF that everyone within 10 miles of that circuit must know what their fucking F/A 18s sound like by now so will they please go off and fucking bomb somebody with them. Everyone would be so grateful.
Fuck me gently with jet engine. I was visiting someone in Port Melbourne yesterday when the buggers flew over (actually just one bugger) and I was told to 'come quick, look' and spend ten minutes gurning at the fighter like a someone who's never seen a plane before. God, I feel like such a twat admitting that, but I must also admit that I now realise that the annoying noise I've been whinging about is nothing compared to the ear splitting, sky rending, brain numbing, mind buggering sound when almost right under the fuckers.


Did you ever hear Concorde? Well when an F/A18 is only a few hundred feet up and wants to be somewhere else in a hurry it's a bit like that. You get that sensation in your chest and certain things around the house probably shake briefly. I thought 'Concorde, big aircraft, four big engines, 60s tech, fair enough - little plane, two engines, should be the right roary sort of noise but loud TV sort volume'. Nope. It's bloody loud and I grinned and pointed and mouthed inaudibly like a five year old. Even if Concorde could do it from a lot higher up it was still bloody impressive, and makes me wonder why it was so loud. I've been stuck in traffic on the A30 under the Heathrow approach and had Airbuses and Boeings pass overhead at similar altitude, but I'm sure the little single seat fighter plane yesterday was at least as loud as any of them, if not louder.

So I'm left with mixed feelings about it. I'd like to understand why F/A 18s (fighters generally, perhaps, does anyone know) seem able to do a Spinal Tap and turn the dial up to 11, and obviously I'm fucking glad I don't live any closer than I do. But if I'm honest I was five years old all the way home yesterday afternoon and still a bit of a five year old today. And if I had a spare $100 million I'd probably buy one.

I might even go to the grand Prix next year so I can hear it again.


JuliaM said...

Ahh, lovely! Still have fond memories of a Fairford airshow years ago, with the Vulcan bomber practically overhead displaying its open bay doors, the noise so loud you felt it more than heard it, and the vibration set off all the car alarms...

Happy days!

Chuckles said...

If your tail was on fire you'd also make a lot of noise and piss off at high speed?

Thank him.

microdave said...

Afterburners, dear boy, afterburners.

Jet fighters have them, so did Concord. A cheap way of dramatically increasing thrust. A ring of nozzles spray neat fuel into the exhaust which ignites, and turns it into a giant blowtorch. You can easily see when they are activated!

I once visited Heathrow with a aviation enthusiasts group, and watched (and listened) as the legendary airliner took off for JFK. It WAS bloody noisy!

Angry Exile said...

I know what afterburners are and I knew Concorde had 'em. I seem to recall a weird procedure of turning them on for take off, then off again for a while, then on again for a bit and then off again after breaking the sound barrier - I'd have to look it up but I'm pretty sure it actually supercruised once the afterburners had done their jobs. For 60s technology that's mindblowing. But going back to the F/A 18 on Sunday afternoon, it may have had the burners on for the high speed fly-bys, though I doubt they'd have been allowed at a few hundred feet over residential suburbs with a lot of wobbly old termite ridden buildings. But what really makes me doubt it was burners is that it was still making a colossal noise doing slow turns over the neighbourhood. And as you say, you'd expect the be able to see when the burners are on. Maybe it's a fuselage vs podded thing. Or low vs high bypass. Dunno really, just speculating now, but I'd be surprised if it turned out to be burner. Happily eat my words if it was though.

Chuckles, excellent link with a fascinating history. Thanks for that. JuliaM, my Dad was a big fan (a turbo fan> - bwahahaha) of Vulcans and I vaguely remember him being 5 years old at an airshow when I really was about 5 years old, or not much more, when one flew by. Must be hereditary. :-) Actually that's reminded me that Concorde's engines were a development of the Vulcan's. Wonder if that's relevant to the noise. Maybe engines made to make the plane go much faster than airliners go are fundamentally louder.

microdave said...

Sorry! didn't mean to sound condescending...

I think Concorde used them for take off, then turned them off for noise abatement, until over the sea. Then they were used to accelerate to supersonic, and finally turned off. The Russian TU 144 needed them to stay supersonic, which crippled its range, due to the terrible fuel consumption.

They call modern fighter engines "TurboFans", but compared the the ones you will see dangling from Boeing, Airbus etc, they have a relatively low bypass ratio. The sheer diameter of high bypass units would rule them out for small fuselages, and these wouldn't cope with supersonic flight anyway. They also need to be very responsive - something impossible with the considerable inertia of a massive fan bolted on the front.

I remember when the USAF A10 "Tankbusters" were based at Woodbridge - these did have high bypass engines, and were remarkably quiet, but only did about 300 knots, as I recall.

I filmed the Vulcan's "Final Flight", but now it's back doing the airshow circuit again, after a remarkable privately funded restoration effort.

Angry Exile said...

S'okay, microdave. I didn't take it as condescension and in turn I hope you didn't think I was being pissy about it.

Yeah, high/low bypass does seem likely. High bypass is built for fuel efficiency and is what you'd normally put on a plane that's supposed to make money for its operator (or for the military maybe longer loiter times), but not if it's something you simply want to go like shit off a shovel. And everything that goes like shit off a shovel tends to be noisier. That's probably the 'what' I guess, but I expect I'd need to get a degree in something to fully understand the 'why'.

microdave said...

Just Google "high bypass turbofan engine", and there are plenty of images which show the difference. The Wiki page is very detailed.

As for noisy aircraft I have been watching and listening (speakers at max!) to lots of the YouTube videos of classic piston engined airliners.
There's nothing to compare with a quartet of 18 cylinder radials churning out in excess of 10,000 hp...

And seeing some of them lovingly restored and maintained by small groups of enthusiasts, lifts my spirits in these depressing times.

Angry Exile said...

I can produce a mental cutaway diagram ( standard to be honest) of a turbofan and high and low bypass speak for themselves. What I don't know enough to understand is why a high bypass engine whines and a low bypass roars.

Don't think I've ever been near enough to a radial to appreciate the sound but I'm glad that there are groups keeping a few examples airborne.

microdave said...

The both make the same high pitched whine due to the speed (anything up to 15,000 rpm) at which the main sections are turning. The High Bypass masks this because of the large volume of air passed around the "Core". This can make up more than 80% of the total thrust. And that huge fan at the front is considerably geared down, hence the "Roar".

He's a few of my favourite "Big Pistons":

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