Why we need sirens, hooters...

[rollerball]

[quote="So interesting though this thread is, it doesn't have much purpose in the real world, IMO.

Not quite. Some years ago we had an aircraft with an engine failure setting up to land on a golf course fairway, only to notice a couple of golfers strolling away right in the wrong place. They showed no notice of his approach and he had no way to warn them, so he diverted to land on a nearby highway and was killed in a collision with a 4wd.....

 

Take your point and genuinely sorry to hear that. But respect to the pilot - at least he did what we might have expected of him, unlike apparently the chap in Portugal.

 

It's a vexing question though as we'd be adding what might be regarded as unnecessary weight to aircraft that would in the great majority of cases never need to be used.

 

BTW like your avatar pic. That was going to be me around rural France this year with the pop-up but have been unfortunately grounded, hopefully not permanently, by dratted illness.

 

 

[Old Koreelah]

You might need a bloody flashbomb..Training with Trevor Bange... he requires that you open the door wide, lean out, shout 'Clear Prop', close and lock the door again, and tighten the harness before you hit the starter. He explained why.

 

One day at Clifton, student training. Nobody but DDSA members around - therefore, experienced aviators. Did the pre-start-up checks, student called 'Clear Prop', hit the starter. A head appeared, looking very startled, just ahead of the prop. The bloke had been crouched down, looking at the front tyre quizzically.

 

You would not credit that, of experienced aviators. But ask Trevor: it happened.

Crikey Oscar, that would have toughened him up! I put two windows in my floor to give me some chance to see dogs, kids, etc, or in the circuit, other aircraft under me. I don't always remember to check that angle, so your story is enough incentive to always check underneath.

 

 

[Head in the clouds]

I used to muster using helicopters and planes with horns and sirens, can't beat loud noisemakers for getting attention on the ground.

 

But - if you find yourself without one when you need it, it's always worth remembering how far your own voice carries, when projected from above, and assuming there's not too much wind or ambient noise on the ground. And also assuming you can open a window ...

 

Anyone who's spent time at a drop-zone will recall how easily canopy sounds and voices can be heard on the ground at opening from 2000ft above.

 

And when training folks in ultralights in the 1980s it was legal and encouraged to switch off the engine and practice dead-stick landings, every 3rd landing or so. We used to switch off above 2000ft and people on the ground could clearly hear the instructor briefing the student during the descent and landing.

 

Unfortunately not likely to help on a beach, with the noise of the wind and/or surf.

 

 

[allowera]

Thanks for all the thoughts.

 

I've had to perform a few go-arounds due to Kangaroos and Cattle on the strip. It has taken up to 3 low passes to get the blighters to clear off.

 

If a noisy Aircraft going a few feet over their heads doesn't motivate them, perhaps a horn might not either. I guess it depends on how deaf/dopey/Darwin(award) the creature is.

 

It's still worth a try though, and I do like the idea of a simple lightweight whistle deployed into the airstream.

 

Perhaps something like a spring loaded 'Shoo-roo' with several lower (audible) pitches?

 

I wonder what the engineers among us could come up with?

 

Cheers.

 

 

[jose miranda]

The deads are a litle girl 8 years old and a man with 52 years

 

 

[houndog]

This tragedy shows that our planes need a lightweight, loud warning device.Two killed in Portugal beach plane crash - BBC News

 

I've been trying to design a large pop-out whistle that could use airflow to make a racket.

Unfortunately having a loud warning device might only encourage a repeat of this selfish behaviour.

 

What are you going to say after you have just killed two people?

 

"They should have heard my siren !!! "

 

 

[ducksrus]

I have a set of airhorns fitted under the cowling pointing downwards and a button mounted just under the LH throttle. I must admit that I have never heard them on the ground when flying, as I am always the one flying, but as Mark Kyle mentions (#27), he heard them ok when I flew over his house at 1200'.

 

They are quite handy to scatter the roo's when taxying out at Ycab and generaly to get peoples attention on the ground sometimes.

 

I also fitted two cheap plastic shoo roo whistles, one to each wing strut. I was a bit sceptical about them, but my son fitted some to his motor home and prior to that he had a few near misses with roo's, but after, he never saw one again. They were only $5 from Supercheap and create minimal drag, not sure what speed range they work in though.

 

 

[Old Koreelah]

After fitting Shoo Roos to my Guzzi I never had a roo jump out in front of me...but I was still hyper vigilant. A small roo had previously taken me off my wife's little Guzzi and it was not fun.

 

 

[Kyle Communications]

I fitted those cheap plastic shoo roo things from Supercheap and I also found that I dont get the kanagroos anymore wanting to leap in front of me when we drive up to the farm...Its amazing how well they work. I didnt believe it but Cosmick on the forum here put me onto them....never thought of fitting them to the aircraft...good idea Steve

 

 

[eightyknots]

Crikey Oscar, that would have toughened him up! I put two windows in my floor to give me some chance to see dogs, kids, etc, or in the circuit, other aircraft under me. I don't always remember to check that angle, so your story is enough incentive to always check underneath.

Where is the picture of the floor windows?

 

 

[eightyknots]

I have a set of airhorns fitted under the cowling pointing downwards and a button mounted just under the LH throttle. I must admit that I have never heard them on the ground when flying, as I am always the one flying, but as Mark Kyle mentions (#27), he heard them ok when I flew over his house at 1200'.They are quite handy to scatter the roo's when taxying out at Ycab and generaly to get peoples attention on the ground sometimes.

I also fitted two cheap plastic shoo roo whistles, one to each wing strut. I was a bit sceptical about them, but my son fitted some to his motor home and prior to that he had a few near misses with roo's, but after, he never saw one again. They were only $5 from Supercheap and create minimal drag, not sure what speed range they work in though.

I hit a kangaroo last December and it is not fun.

 

I like the idea of air horns that Mark and you have fitted to your aircraft. But I wonder how you could warn people on a beach with shuroos? ...the frequency is above the human audible range.

 

 

[Old Koreelah]

I hit a kangaroo last December and it is not fun.I like the idea of air horns that Mark and you have fitted to your aircraft. But I wonder how you could warn people on a beach with shuroos? ...the frequency is above the human audible range.

The discussion had broadened to include warning animals off runways not.

 

 

[Old Koreelah]

Where is the picture of the floor windows?

These are the only pix I can find, 80. Might take a few when next I put the aircraft together and fly- hopefully this Saturday.

 

 

 

 

[APenNameAndThatA]

I use an air horn like this when I as spotting for my son using a chainsaw.

 

Amazon.com : SeaSense Large Air Horn, 8oz : Boat Horns : Sports & Outdoors

 

Aeroprakt has a variation of the Foxbat A22LS called the Kelpie. It is fitted with a mustering horn (electric) and a UHF radio. The hundredth Foxbat was delivered in Australia ? a couple of years ago.

 

 

[APenNameAndThatA]

I understand the need to keep the weight down, but that means your life depends on one or two little bolts.I'm starting to appreciate the one-piece box spar of my Jodel.

Apparently, no 172 has ever broken up in normal flight. ? truth.

 

 

[Oscar]

Unfortunately, high-frequency sound is very directional and also easily blocked (e.g. by earphones playing music from the iPhone/iPod.) So low-energy/high frequency devices - such as piezo tweeters, easy to mount etc. - are seriously compromised.

 

However, sounds issued at down around the human alpha-rate - around 14 Hz, I believe - have a pronounced impact. So - possibly - a purpose-built system that uses piezo tweeters facing forwards BUT cycles the sound pulses at around 14 Hz, might work.

 

This is just a wild thought out of left-field on my part, but maybe someone with the requisite electronic knowledge - such as Mark Kyle - could build a test unit?

 

As for Shoo Roo's: I've had three physical encounters and more near-misses than I care to recall. In all of the hits- the bloody roos ran into ME, from the side, trying to race the car across the road. I've had two front guards bent onto the tyre, and one bastard launched into lunar orbit from the bull-bar on my Rangie at around 130 kph, near '|Hopping Joe Creek' on the Cann River Highway. All came from the side of the road, out of the area likely to be covered by Shoo Roos.

 

Roos make sheep look intelligent.

 

 

[Head in the clouds]

...... In all of the hits- the bloody roos ran into ME, from the side, trying to race the car across the road. .....

Reminds me of an incident that happened to my brother many years ago.

 

He was visiting England and Scotland and driving north in the late evening on a highway near Edinburgh when he and his new wife heard a loud bang which seemed to come from the left rear of the car.

 

Suspecting a tyre problem or something similar they pulled over and had a good look at the rear wheel and found nothing amiss. About to continue the trip one of them noticed what appeared to be two bullet holes in the rear door ...

 

Naturally their first response was to take cover, especially as they had both lived in a war-torn country where such an incident was often the prelude to car-jacking, kidnapping, armed robbery or much worse. Then one of them noticed what appeared to be a body lying a hundred metres or so behind the car.

 

Since she was a nurse they could hardly follow their gut and high-tail it out of there so they reversed to see what they could do to help.

 

It turned out to be a small deer that had butted the side of the car and its horns had made the holes in the door skin. The deer was unconscious and bleeding a little, so, being animal lovers they decided to take it to the nearest vet - they put it on the back seat and headed off.

 

As you might imagine, the deer revived again after a few minutes and set about destroying the car interior ... so was duly released, quick as ...

 

I've heard a couple of similar stories too, where a big red boomer hit by a car comes through the windscreen and sets about the occupants, and an eagle that attacked an ultralight pilot after breaking the windshield.

 

Sorry - rambling on - back to topic if you like ;-)

 

 

[eightyknots]

...

However, sounds issued at down around the human alpha-rate - around 14 Hz, I believe - have a pronounced impact. So - possibly - a purpose-built system that uses piezo tweeters facing forwards BUT cycles the sound pulses at around 14 Hz, might work.

 

This is just a wild thought out of left-field on my part, but maybe someone with the requisite electronic knowledge - such as Mark Kyle - could build a test unit?

 

....

As long as the high intensity 14 Hz sound doesn't shake the aircraft to pieces!

 

 

[Head in the clouds]

As long as the high intensity 14 Hz sound doesn't shake the aircraft to pieces!

Good point - rubber mounts ..?

 

 

[onetrack]

The Whelen Howler is what you're all looking for. It even includes a loudspeaker. As used by U.S. law enforcement.

 

Whelen Howler Siren and Speaker System using Low Frequency Tone

 

 

[Steve L]

Aussie ambulance sirens would be the go. Don't know how heavy or bulky they are though.

 

 

[Yenn]

If 14 Hertz is the correct frequency, would a 14 Hertz transmitter be appropriate? Wouldn't the forward speed of the plane contribute to doppler effect needing an even lower frequency.

 

 

[AussieB1rd]

I have a set of airhorns fitted under the cowling pointing downwards and a button mounted just under the LH throttle. I must admit that I have never heard them on the ground when flying, as I am always the one flying, but as Mark Kyle mentions (#27), he heard them ok when I flew over his house at 1200'

I have heard them a couple of times and had me jump, your not expecting a blast like that from an aircraft and I think it's most effective for clearing stock or wildlife off a strip or getting attention to those on the ground.

 

 

[danny_galaga]

Haven't read the whole thread, but not sure why you couldn't just use a regular car horn? I mean, if it's good enough in a supercar...

[rankamateur]

Aircraft designers' maxim: add lightness

A bloke I have learnt a lot from always say 'if it looks strong enough, it is already too heavy!'