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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.
Aircraft Engine Messaging
Aircraft_20Engine_20Messaging
[xaviergisz, Aug 29 2010]
21 Quest's hypno propeller pattern
http://www.tomheroe...0ads/hypno_coin.htm
Were you guys painting this pattern on those C-130 props? [doctorremulac3, Sep 01 2010]
Tip lights like this?
http://chivethebrig...rs-night-920-21.jpg
Dunno how, this was just in a set of pretty pictures. [baconbrain, Jul 23 2011]
Another approach
Strobe_20Lit_20Aircraft_20Propeller
Inspired by this idea [doctorremulac3, Jul 23 2011]
My sentiments exactly
http://www.youtube....=PLE499001A18B988CF
The most eloquent commentary on the P-51 I've ever seen. [doctorremulac3, Jul 24 2011]
Sun Tzu
http://en.wikipedia.org/wiki/Sun_tzu
Required reading [8th of 7, Jul 28 2011]
Starjammer video
http://www.elginwel...%20Minute%20NoW.wmv
Double-click to view full size. [Klaatu, Jul 29 2011]
Rotor tip lights?
http://chivethebrig...-07_29_11-920-3.jpg
It may be. [baconbrain, Jul 30 2011]
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[+] for the sentiment, but we agree with [21Q]. |
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It would be possible to produce a self-contained unit powered by a battery, and switched by an RF signal. No wiring. |
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// One was the risk of being mesmerized by the blades, and slowly walking straight into them, eyes locked on.// |
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Zombies and propeller aircraft don't mix. |
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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] |
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Load some short-life batteries into the blade tips before you fire up the engine. |
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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. |
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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. |
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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. |
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How about signs saying, "BIG SHARP WHIRLY METAL THING THAT WILL KILL YOU" ? |
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and another (+) for [Custardgut]'s anno.
A chomping pac man would be good. |
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So molecular laminar flow conditioning by specialized
LEDs? |
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Clever idea but I think the lights would obstruct the
pilot's field of vision at night. At least on single
engine planes. |
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They would only need to be lit when there's weight on the wheels. |
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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. |
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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. |
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No reason to not do this for twin engine planes
though. |
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//One was the risk of being mesmerized by the
blades, and slowly walking straight into them, eyes
locked on.// |
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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. ;) |
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The lights could be put on the front face of the propellor, and not even be visible to the pilot. |
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But then people could walk into it from behind no? |
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Actually, laser beams coming out the tips would be
cool. Don't think they'd be very popular with the
other pilots though. |
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// But then people could walk into it from behind no? // |
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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. |
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"Did you hear about the butcher who backed into a meat grinder? He got a little behind in his work." |
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RS. (My proposed new texting acronym for "rim shot") |
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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. |
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It's more of a problem where the wing is high enough to walk under. |
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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 ... |
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Which would kill you. Good point, [8th]. |
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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. |
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"It is impossible to make anything foolproof, because fools are so ingenious." |
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/One was the risk of being mesmerized by the blades, and slowly walking straight into them, eyes locked on./ |
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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. |
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//the original wartime use of propellers...go all glassy eyed...march right into them until the carnage fouled the blades// |
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That explains why I keep staring at this damn desk fan. Fingering the guard, trying to find a hole big enough...shit! |
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//the original wartime use of propellers...go all glassy eyed...march right into them until the carnage fouled the blades// |
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Can we get a source on this? |
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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. |
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Speaking as someone who knows nothing about
aerodynamics... |
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If you caged the propeller, would it affect the plane's flight? |
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//If you caged the propeller, would it affect the plane's flight?// |
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It's an aerodynamic advantage in ducted fan aircraft (where it's a partial cage) and a safety feature in fan boats. |
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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. |
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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. |
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I'm sure there's a better 'splanation out there though. |
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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. |
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[21] I think the idea was a circumferential cage (ie, basically
a very short duct), leaving the front and rear open. |
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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. |
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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. |
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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. |
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//with the blade ends within just a scootch of the duct is a
long, hard job// |
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Or just make the duct out of something softer than the prop
blade tips, and slowly fit the duct while the prop is
running... |
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/Or just make the duct out of something softer than the prop blade tips, and slowly fit the duct while the prop is running/ |
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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. |
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Interesting. But what happens to the clearance when the engine thrashes up and down as always happens during shut-down? |
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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. |
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/smooth bore/
the residual nooks and crannies produce laminar airflow, just like the dimples in a golf ball. |
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/thrashing/
it can thrash in a piece. |
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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. |
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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. |
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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'. |
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//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. |
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// "spinning mincy thing not far on the left" // |
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Then it'd be beeping every time I got near my uncle Roger. |
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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? |
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Clearly some kind of "spinning mincy thing sign"
illumination system is in order. |
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bun for "spinning mincy thing detector" |
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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. |
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[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. |
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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. |
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Conclusion of anecdotal diatribe. |
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Ahh, the P-51. Best airframe and engine of the war. See what happens when Americans and Brits play nice? |
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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. |
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//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. |
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Now we know that you truly have no soul, [Abs]. |
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Ha! I read the last part of that in his voice. |
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// what happens when Americans and Brits play nice // |
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It's called Canada, and it's horrible. |
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// gorgeous hunk of iron // |
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Duralumin, but we'll at you off this time. |
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//don't you need a smooth bore ?//
Someone call me? |
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// It's called Canada, and it's horrible. // |
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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. |
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// what happens when Americans and Brits play nice
// |
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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). |
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// Oh, and really awesome airplanes get built (modern example: Harrier).//
What has the Hawker Harrier got to do with Americans? (apart from buying them?) |
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We gave the brits the idea by building VTOLs that sucked. |
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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. |
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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. |
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Oh, and apparently the D-Day landings were an entirely U.S. operation. |
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[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. |
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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. |
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Methinks [8th_of_7] doth protest too much. |
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// hard historical proof that the Canadians were also involved // |
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Undeniable; they're still clearing away the piles of empty bottles in Normandy. |
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// Monty was a windbag // |
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... 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). |
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// developed through Hawker/DARPA/Fleet Air Arm collaberation // |
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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" ? |
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Or "collaboration" as in "A few french people didn't like the Germans very much, and sometimes said rude things about them in private" ? |
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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 ... |
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"Pas de Calais in 48 hours!" |
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How long exactly did it take him? |
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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. |
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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. |
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// How long exactly did it take him? // |
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Well, yes, admittedly slightly longer than "Hurrying Heinz" Guderian, but then the Germans were actually fighting back in 1944 ... |
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// refused to acknowledge his own shortcomings // |
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Freddy De Guingand's memoirs effectively refute this. |
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In the face of total defeat, total defiance is the only option. |
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A tactician, but not a strategist. |
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Anyone can win a battle if they have limitless manpower and have no concern about casualties. |
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// Subtlety and dynamism are virtues of a true warrior.// |
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... but the greatest virtue is arranging affairs so that you don't have to fight at all, Clausewitz or not. |
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// the greatest virtue is arranging affairs so that you don't have to fight at all // |
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// In the face of total defeat, total defiance is the only option. // |
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Ah, but what masterful defiance it was. |
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In terms of brevity, it is indeed hard to outdo "Nuts !". |
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And, of course, you and I will always agree on Vimes. |
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Unless I side with Vetinari out of spite, that is. |
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… or perhaps an unerring instinct for self-preservation, as per
Moist von Lipwig… |
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You see, the thing about angels is... |
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//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. |
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//In terms of brevity, it is indeed hard to outdo
"Nuts !"// How about le mot de Cambronne? |
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He doesn't. He's talking about Kursk. |
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Kursk? I thought Stalingrad.
[8th]'s position's even weaker than I thought. |
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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. |
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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. |
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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. |
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Le Mot De Cambronne has five letters, not four; trust the french
to be long-winded. |
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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. |
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// Can't wait to see how they handle this // |
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By a calculated and stubborn defence, trading space for time,
and awaiting the onslaught of General January and General
February. |
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If we can get any more history nuts in on this, it could be a
real Sevastopol. |
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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? |
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If so, we will post our traditional Crimea Christmas Dinner recipe
for Boiled Hat in Mud Sauce. |
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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 |
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Actually I meant massive caliber ordnance bombarding you
from every direction. |
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But one of the letters is silent. What's long
winded is calling it "le mot de Cambronne," rather
than using the actual word. |
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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. |
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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. |
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(I have it on good authority -- Shaw's _Arms and
the Man_ -- that a cavalry charge against artillery
is quite an effective tactic.) |
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The Starjammer takes this to another level, including a
4000 watt sound system. <link> |
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Going back along this anno thread about six years.... |
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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. |
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Just thought I'd stick that in randomly. |
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////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. |
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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. |
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// he survived to enjoy it // |
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That's always good, from the point of view of the speaker. |
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// the P-47 was an undersung hero // |
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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. |
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The P-47 was at least as good in the ground attack fighter/bomber role as the Hawker Typhoon. |
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... for which they will roast in Hell for all Eternity. |
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Q: What do you call a conservator who colorizes a
work that was originally monochrome? |
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A: Lots of things, but "conservator" isn't one of
them. |
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