I read in the news today that a pilot was killed because he walked into a spinning propeller. It happens every once in a while. Some props have colored tips to make them easier to see in the day, but they are especially invisible at night.
My idea is to place bright LED lights on the tips of propeller blades. To avoid the complication of running wires through the spinner (and partly for coolness) the lights should be powered by electromagnetic induction. They will be energized as they pass by an electromagnet on the engine cowling. To avoid the distraction of having a bright spinning disk in front of the window after takeoff, the magnet can be switched off by the pilot.
Besides the safety benefit it would look really cool.-- DIYMatt, Aug 29 2010 Aircraft Engine Messaging Aircraft_20Engine_20Messaging [xaviergisz, Aug 29 2010] 21 Quest's hypno propeller pattern http://www.tomheroe...0ads/hypno_coin.htmWere you guys painting this pattern on those C-130 props? [doctorremulac3, Sep 01 2010] Tip lights like this? http://chivethebrig...rs-night-920-21.jpgDunno how, this was just in a set of pretty pictures. [baconbrain, Jul 23 2011] Another approach Strobe_20Lit_20Aircraft_20PropellerInspired by this idea [doctorremulac3, Jul 23 2011] My sentiments exactly http://www.youtube....=PLE499001A18B988CFThe most eloquent commentary on the P-51 I've ever seen. [doctorremulac3, Jul 24 2011] Sun Tzu http://en.wikipedia.org/wiki/Sun_tzuRequired reading [8th of 7, Jul 28 2011] Starjammer video http://www.elginwel...%20Minute%20NoW.wmvDouble-click to view full size. [Klaatu, Jul 29 2011] Rotor tip lights? http://chivethebrig...-07_29_11-920-3.jpgIt may be. [baconbrain, Jul 30 2011] [+] for the sentiment, but we agree with [21Q].-- 8th of 7, Aug 29 2010 It would be possible to produce a self-contained unit powered by a battery, and switched by an RF signal. No wiring.-- 8th of 7, Aug 29 2010 // One was the risk of being mesmerized by the blades, and slowly walking straight into them, eyes locked on.//
Zombies and propeller aircraft don't mix.-- ldischler, Aug 29 2010 Ooooh! Next idea - synchronised propeller messages via LED. Put rows of LED's down the edge of the propeller blades, and computer control them so they can flash on/off in synch with the blade rotation to display messages (like those desk toys you can buy) : DO NOT WALK INTO THIS PROPELLER or something smarmy about owning your own plane. [Aargh. beaten by xaviergisz's link, apparently I'm not very original]-- Custardguts, Aug 29 2010 Load some short-life batteries into the blade tips before you fire up the engine.
I once clonked my forehead really hard on the trailing edge of a rotor blade. I recall running my fingers up the side of my head, expecting to feel a sliced-off top--the rotor had been spinning furiously just a few minutes before, and I was really groggy.
No amount of lights would have prevented that particular accident. I just turned and walked without realizing the blade had drifted from where I last saw it.-- baconbrain, Aug 29 2010 generally these accidents involve ground crew who are described as "backing into" props while wearing hearing protecting ear muffs. The general consensus is that we should either keep people 100 percent away from the kill zone or make sure that everyone in that zone can hear (noise LIMITING) and has unrestricted peripheral vision. This would be effective prevention in most cases.-- WcW, Aug 29 2010 How about signs saying, "BIG SHARP WHIRLY METAL THING THAT WILL KILL YOU" ?-- 8th of 7, Aug 29 2010 (+)
and another (+) for [Custardgut]'s anno.A chomping pac man would be good.-- 2 fries shy of a happy meal, Aug 29 2010 So molecular laminar flow conditioning by specialized LEDs?-- wjt, Aug 30 2010 Clever idea but I think the lights would obstruct the pilot's field of vision at night. At least on single engine planes.-- doctorremulac3, Sep 01 2010 They would only need to be lit when there's weight on the wheels.-- 2 fries shy of a happy meal, Sep 01 2010 I can tell you from experience, at least with small single engine craft, the time you have the most trouble seeing where you're going is when you're taxiing. I think most pilots would tell you it's most definitely the "un-fun" part of flying.
Imagine driving your car through a crowded parking lot with ten foot extensions sticking out of the sides of your vehicle trying to not hit any of the other parked cars and their ten foot extensions. Keep in mind, airplanes steer like a drunk cow when they're on the ground. Then throw a strobe light onto your hood to boot.
No reason to not do this for twin engine planes though.-- doctorremulac3, Sep 01 2010 //One was the risk of being mesmerized by the blades, and slowly walking straight into them, eyes locked on.//
Hey 21 Quest, you guys weren't painting this pattern on the blades were you? (see link) If so that's your problem right there. ;)-- doctorremulac3, Sep 01 2010 The lights could be put on the front face of the propellor, and not even be visible to the pilot.-- baconbrain, Sep 01 2010 But then people could walk into it from behind no?-- doctorremulac3, Sep 01 2010 Actually, laser beams coming out the tips would be cool. Don't think they'd be very popular with the other pilots though.-- doctorremulac3, Sep 01 2010 // But then people could walk into it from behind no? //
Yeah, but a guy who is walking past an airplane and vibrating airplane engine, into a thudding propellor blast may suspect that there is a propellor in front of him. They could keep going, I suppose.
"Did you hear about the butcher who backed into a meat grinder? He got a little behind in his work."-- baconbrain, Sep 01 2010 RS. (My proposed new texting acronym for "rim shot")-- doctorremulac3, Sep 02 2010 Bear in mind that this problem is more or less limited to larger aircraft. On a puddle-jumper, it's not that easy to get at the prop from behind, and from in front there is always the handy status indicator of an irate pilot, shouting and gesturing. On a twin, the wings are in the way.
It's more of a problem where the wing is high enough to walk under.
As [baconbrain] says, approaching a turning prop from the rear usually means moving into a progressively stronger air blast, unless neutral pitch is selected and the engine is practically idling ...-- 8th of 7, Sep 02 2010 Which would kill you. Good point, [8th].
My aviation background mostly involves little airplanes. It is hard to walk into the prop of a Cessna 150 from the back, but it has been done.-- baconbrain, Sep 02 2010 "It is impossible to make anything foolproof, because fools are so ingenious."-- 8th of 7, Sep 02 2010 /One was the risk of being mesmerized by the blades, and slowly walking straight into them, eyes locked on./
My understanding is that this was the original wartime use of propellers, during the Crimean war. Hand cranked propellers would be set up in view of the Russians who would go all glassy eyed and march right into them until the carnage fouled the blades.-- bungston, Sep 02 2010 //the original wartime use of propellers...go all glassy eyed...march right into them until the carnage fouled the blades//
That explains why I keep staring at this damn desk fan. Fingering the guard, trying to find a hole big enough...shit!-- ldischler, Sep 03 2010 //the original wartime use of propellers...go all glassy eyed...march right into them until the carnage fouled the blades//
Can we get a source on this?-- DIYMatt, Sep 03 2010 The source? Bungston.-- ldischler, Sep 03 2010 Evolutionary biology is said to have a problem explaining flight, since the first winglike structures, incapable of flight, would have to have enjoyed some other evolutionary advantage, in order to be preferentially inherited and elaborated in subsequent generations. As far as I know, no one's ever raised the same question regarding the development of airplanes. Undaunted by the lack of a question, [bungston] has supplied the answer.-- mouseposture, Sep 03 2010 Speaking as someone who knows nothing about aerodynamics...
If you caged the propeller, would it affect the plane's flight?-- DrWorm, Sep 03 2010 //If you caged the propeller, would it affect the plane's flight?//
It's an aerodynamic advantage in ducted fan aircraft (where it's a partial cage) and a safety feature in fan boats.-- ldischler, Sep 03 2010 I never found out why all propeller aircraft don't use ducted fans. You get more thrust, they're quieter, you reduce the induced drag caused by the propeller tips, you aren't spraying much of your thrust out the sides since the duct catches it and directs it backwards. All this in addition to it being safer.
I'm thinking the truth is they just don't look cool. Imagine a P-51 Mustang or a Spitfire with a duct? Ug. Maybe it's like velcro on dress shoes.
I'm sure there's a better 'splanation out there though.-- doctorremulac3, Sep 03 2010 I assumed the explanation was some lack of efficiency: same reason that the windmill people dont put a circumferential rim around their blades for when the hawks try to sit on them.-- bungston, Sep 03 2010 [21] I think the idea was a circumferential cage (ie, basically a very short duct), leaving the front and rear open.
It is an interesting question as to why they're not used - I too was under the impression that ducting a propellor in this way improved its thrust.-- MaxwellBuchanan, Sep 03 2010 Ducted fans are more efficient, but ducted propellors are not. It has to do with the diameters and airspeeds and numbers of blades. Generally, a larger-diameter airmover is better, but only at lower speeds. There's a sliding scale where a duct is worth doing or not. Jet airplanes like 747s have fat high-bypass ducted fans where they used to have skinny engines. Slow little airplanes have long skinny two-blade props. It's a science, best learned by reading Bill Gunston.
In short, though, you can whittle a fairly good prop out of a piece of wood and bolt it on the front of an engine and do pretty well. Making a well-shaped duct, and getting the carefully-designed prop inside it to run with the blade ends within just a scootch of the duct is a long, hard job.-- baconbrain, Sep 03 2010 //with the blade ends within just a scootch of the duct is a long, hard job//
Or just make the duct out of something softer than the prop blade tips, and slowly fit the duct while the prop is running...-- MaxwellBuchanan, Sep 03 2010 /Or just make the duct out of something softer than the prop blade tips, and slowly fit the duct while the prop is running/
I like that. It could work. You could use epoxy putty, shape it with the prop, let it harden, then mount it within a generic duct holder. You could then still use the whittled and variable propellors.-- bungston, Sep 03 2010 Interesting. But what happens to the clearance when the engine thrashes up and down as always happens during shut-down?
Although I do like the logical-progression idea of glopping a lot of soft stuff on an airframe, taking a spin around the field, and spraying hardener on whatever is left.-- baconbrain, Sep 04 2010 /smooth bore/ the residual nooks and crannies produce laminar airflow, just like the dimples in a golf ball.
/thrashing/ it can thrash in a piece.-- bungston, Sep 04 2010 I think there's also reluctance to spend money on a safety measure to protect anybody stupid enough to get close to a screaming loud, insanely fast spinning object that generates a hurricane force wind.
I've been next to plenty of spinning props and you can't miss these things. It's like a roaring lion. You have to shout just to be heard and that's even with a small plane. Now stand next to some really big iron like a WW2 warbird and there's very little you could do to add to the "warning factor" inherent in a ten foot blade being spun at 2000 rpm by a 1,500 horse power engine.
In other words, people say: "Is it worth spending $500 to save somebody that dumb?" I don't necessarily agree with that, I'm just sayin'.-- doctorremulac3, Sep 04 2010 //I'm just sayin'// dunno, I imagine people who work flightlines in rain and wind, in a field full of sound-reflecting buildings and aircraft variously running up, down and idling, while wearing ear-defenders which screw up binaural hearing, for 7-8 hours a day, might see it a bit differently than a Darwin award that you really have to work at to get.-- FlyingToaster, Sep 04 2010 Yea, what FT says.-- doctorremulac3, Sep 04 2010 // "spinning mincy thing not far on the left" //
Then it'd be beeping every time I got near my uncle Roger.
Not that HE would mind.
Gracious, no.-- baconbrain, Sep 04 2010 Yea, but how them flight line workers gonna see that spinning mincy thing sign during Halloween when they're wearing a Darth Vader or Winnie the Pooh mask? And what if it's the prom and they're wearing a chiffon evening gown? How you gonna keep that from getting tangled in the propeller?
Clearly some kind of "spinning mincy thing sign" illumination system is in order.-- doctorremulac3, Sep 04 2010 bun for "spinning mincy thing detector"-- FlyingToaster, Sep 04 2010 By embedding LEDs along the length of the blade, and careful synchronisation of their illumination with prop position, they could spell DEATH in big red letters, the same way that those clocks with the waving arm thing show the time.-- 8th of 7, Sep 04 2010 [FT] has it absolutely right: you work in a dangerous environment long enough, you get comfortable. You get too comfortable, you get complacent. You get too complactent, you get hurt.
Most people would be intimidated by a cutting torch with a 9" flame on the end, but I've had many a conversation with co-workers where one or the other of us was gesturing with a lit torch like most people gesture with their hands. I've also been clipped by the handle of a box-car door at the end of a long day because I was standing a lot closer to a moving train than I thought. Even though I, too, have stood next to a running P-51 Mustang on one wonderful day at Duxford that I shall treasure the memory of as long as I shall live, and thus felt the incredible power of a prop-aircraft at close range, I'm absolutely positive that one can become just as complacent around them as I am with extremely hot flames and heavy bits of steel.
Conclusion of anecdotal diatribe.-- Alterother, Jul 23 2011 Ahh, the P-51. Best airframe and engine of the war. See what happens when Americans and Brits play nice?
Not the last propeller driven fighter to occasionally take on jets and win, that would probably be the Skyraider in Vietnam, but most definitely one gorgeous hunk of iron.-- doctorremulac3, Jul 24 2011 //and thus felt the incredible power of a prop-aircraft at close range, //But just imagine how much less buffeting you would have experienced had it been designed by James Dyson, and with no nasty rotating blades to walk into.-- AbsintheWithoutLeave, Jul 24 2011 Now we know that you truly have no soul, [Abs].-- 8th of 7, Jul 24 2011 Ha! I read the last part of that in his voice.
Too funny.-- 2 fries shy of a happy meal, Jul 24 2011 // what happens when Americans and Brits play nice //
It's called Canada, and it's horrible.
// gorgeous hunk of iron //
Duralumin, but we'll at you off this time.-- 8th of 7, Jul 24 2011 //don't you need a smooth bore ?//Someone call me?-- AbsintheWithoutLeave, Jul 28 2011 // It's called Canada, and it's horrible. //
Only the parts that don't want to be Canada anymore. I happen to think the regions that are happy with thier nationality, and, coincidentally, speak the proper language, are quite nice.-- Alterother, Jul 28 2011 // what happens when Americans and Brits play nice //
The French never give credit when it's due, and the Russians never get acknowledged for pretty much fighting the whole goddamn war themselves. Oh, and really awesome airplanes get built (modern example: Harrier).-- Alterother, Jul 28 2011 // Oh, and really awesome airplanes get built (modern example: Harrier).//What has the Hawker Harrier got to do with Americans? (apart from buying them?)-- AbsintheWithoutLeave, Jul 28 2011 We gave the brits the idea by building VTOLs that sucked.-- Alterother, Jul 28 2011 It was invented by the Americans, about the same time their Air Force were winning the Battle of Britain with their Kittyhawk fighters (which - strangely - were later blown out of the sky in huge numbers by Mitsubishi Zeros and relegated to a training role), their B-17's were bombing the dams in the Ruhr, and their Navy was capturing the Enigma machine and its codes from a U-boat, running convoys to Malta, sinking the Bismark and the Graf Spee, and attacking the Tirpitz with midget submarines.
All that, and they still managed to invent the fission bomb all on their own, without any help whatsoever from emigre Hungarians, Germans, Italians, or the British team that developed gaseous-diffusion isotope separation.
Oh, and apparently the D-Day landings were an entirely U.S. operation.-- 8th of 7, Jul 28 2011 [8th] I take offense to the D-Day statement. I have hard historical proof that the Canadians were also involved. Oh, and Monty was a windbag.
Concerning the Harrier: greater specificity may have been in order, as I was referring to the modern version of the Harrier (sometimes called the Harrier II), which came about due to the USMCs commitment to purchase the vehicle contingent on several improvements/modifications, which were readily accepted by Hawker and developed through Hawker/DARPA/Fleet Air Arm collaberation.-- Alterother, Jul 28 2011 Methinks [8th_of_7] doth protest too much.-- mouseposture, Jul 28 2011 // hard historical proof that the Canadians were also involved //
Undeniable; they're still clearing away the piles of empty bottles in Normandy.
// Monty was a windbag //
... and a better commander than Bradley, Patton or Clark any day of the week. We'll see your Kasserine and and raise you an El Alamein (II).
// developed through Hawker/DARPA/Fleet Air Arm collaberation //
Collaboration, as in "the British supplied all the concepts, skill and manufacturing capability, and the Americans paid for it, including being taught how to fly a V/STOL from a carrier" ?
Yes, fair enough.
Or "collaboration" as in "A few french people didn't like the Germans very much, and sometimes said rude things about them in private" ?
We look forward to their no doubt outstanding performances in Track and Field at the 2012 London Olympics; after all, the buggers ran like rabbits in 1940 ...-- 8th of 7, Jul 28 2011 "Pas de Calais in 48 hours!"
How long exactly did it take him?
I won't deny Monty was a military genius. I simply contend that he was a windbag military genius who refused to acknowledge his own shortcomings.
And just for the record, so was Patton. I'm really more of a fan of McAuliffe, Rommel, Zhukov, etc. Subtlety and dynamism are virtues of a true warrior.-- Alterother, Jul 28 2011 // How long exactly did it take him? //
Well, yes, admittedly slightly longer than "Hurrying Heinz" Guderian, but then the Germans were actually fighting back in 1944 ...
// refused to acknowledge his own shortcomings //
Freddy De Guingand's memoirs effectively refute this.
// McAuliffe, //
In the face of total defeat, total defiance is the only option.
// Rommel //
A tactician, but not a strategist.
// Zhukov,//
Anyone can win a battle if they have limitless manpower and have no concern about casualties.
// Subtlety and dynamism are virtues of a true warrior.//
... but the greatest virtue is arranging affairs so that you don't have to fight at all, Clausewitz or not.
<link>-- 8th of 7, Jul 28 2011 // the greatest virtue is arranging affairs so that you don't have to fight at all //
Readily agreed.
// In the face of total defeat, total defiance is the only option. //
Ah, but what masterful defiance it was.-- Alterother, Jul 28 2011 In terms of brevity, it is indeed hard to outdo "Nuts !".-- 8th of 7, Jul 28 2011 And, of course, you and I will always agree on Vimes.
Unless I side with Vetinari out of spite, that is.-- Alterother, Jul 28 2011 … or perhaps an unerring instinct for self-preservation, as per Moist von Lipwig…-- 8th of 7, Jul 28 2011 You see, the thing about angels is...-- Alterother, Jul 28 2011 //Anyone can win a battle if they have limitless manpower and have no concern about casualties.// I'm curious to know how you reconcile that with the Soviet experience in Finland.
//In terms of brevity, it is indeed hard to outdo "Nuts !"// How about le mot de Cambronne?-- mouseposture, Jul 28 2011 He doesn't. He's talking about Kursk.-- Alterother, Jul 28 2011 Kursk? I thought Stalingrad. [8th]'s position's even weaker than I thought.-- mouseposture, Jul 28 2011 Actually, I was thinking of Stalingrad when I brought him up; backs to the river, no re-supply or reinforcement until the ice freezes, fighting an enemy with both superior firepower and almost total air supremacy... but your example is even better.-- Alterother, Jul 28 2011 Rhetorically speaking, [8th]'s position is much the same as the Russians' at Stalingrad. Or maybe Leningrad. Can't wait to see how they handle this.-- mouseposture, Jul 28 2011 Au contraire; throughout the battle, the link across the Volga was maintained, usually at night; just enough reinforcement was provided to keep the Germans fully engaged, while forces were built up to the north and south, forming the pincers that eventually cut off the 'kessel'. We commend to you Anthony Beevor's excellent work on the subject.
Le Mot De Cambronne has five letters, not four; trust the french to be long-winded.
As to Finland, the Finns initially stood off the Soviets, but Mannerheim was eventually forced into a peace deal which involved yeilding a lot of territory.
// Can't wait to see how they handle this //
By a calculated and stubborn defence, trading space for time, and awaiting the onslaught of General January and General February.-- 8th of 7, Jul 28 2011 If we can get any more history nuts in on this, it could be a real Sevastopol.-- Alterother, Jul 28 2011 As in the casualties from starvation, malnutrition, preventable infectious disease, exposure and shipwreck vastly outnumber battle casualties, due to a total lack of preparedness, a woefully inefficient logistics tail, and promotion of officers based on wealth rather than any actual ability?
If so, we will post our traditional Crimea Christmas Dinner recipe for Boiled Hat in Mud Sauce.
Oh and if you see Lord Lucan, tell him they're not over here. Apparently he has lost the Light Brigade. Terribly careless, he should have put them back in the box when he'd finished with them-- 8th of 7, Jul 28 2011 Actually I meant massive caliber ordnance bombarding you from every direction.-- Alterother, Jul 28 2011 But one of the letters is silent. What's long winded is calling it "le mot de Cambronne," rather than using the actual word.
You're not distinguishing "battle," of which the Soviets lost many, in Finland, from "war" of which they lost only one out of two. Actually, under the circumstances, and considering that Finland continued to exist, Mannerheim didn't do so badly. You would definitely enjoy Trotter's book on the subject, if you haven't already read it.
As for the "General January / General February" thing: it's a canard, in 1942 as in 1812, things turned around before December. They weren't waiting for cold weather; they were waiting for reinforcements, which, unlike weather, were the product of hard work by dedicated, competent people.
(I have it on good authority -- Shaw's _Arms and the Man_ -- that a cavalry charge against artillery is quite an effective tactic.)-- mouseposture, Jul 29 2011 The Starjammer takes this to another level, including a 4000 watt sound system. <link>-- Klaatu, Jul 29 2011 Going back along this anno thread about six years....
I've always thought the P-47 was an undersung hero. The P-51 was obviously superior as dogfighter, but the Jug was one helluva beastly airplane, and I think more versatile.
Just thought I'd stick that in randomly.-- Alterother, Jul 29 2011 ////In terms of brevity, it is indeed hard to outdo "Nuts !"// How about le mot de Cambronne? — mouseposture, Jul 28 2011 // To be fair, McAuliffe was more succinct and successful with his bon mot.-- AbsintheWithoutLeave, Aug 01 2011 And, thanks mostly to the era/setting in which it was delivered, he earned infinitely more immediate popularity for it. Also, he survived to enjoy it.-- Alterother, Aug 01 2011 // he survived to enjoy it //
That's always good, from the point of view of the speaker.
// the P-47 was an undersung hero //
A fine aircraft, merely lacking the superb high altitude performance conferred by the supercharged British Rolls-Royce Merlin; the P-51 would have similarly languished, had it retained its original Allison engine. While the P-47 was fairly agile at 30,000 ft, it was still a big, heavy plane to throw around, and the complexity of the compound turbo-supercharger told against it.
The P-47 was at least as good in the ground attack fighter/bomber role as the Hawker Typhoon.-- 8th of 7, Aug 01 2011 ... for which they will roast in Hell for all Eternity.-- 8th of 7, Aug 01 2011 Q: What do you call a conservator who colorizes a work that was originally monochrome?
A: Lots of things, but "conservator" isn't one of them.-- mouseposture, Aug 02 2011 random, halfbakery