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Led Sikorsky

POV Rotors
  (+8, -1)
(+8, -1)
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Why has nobody thought yet to incorporate LED lights to the underside of a helicopters spinning blades to create a persistence of vision display?

Must I do everythink myself?

Done on small r/c helicopters, 2013 https://technabob.c...-helicopter-writer/
[kdf, Sep 27 2020]

An earlier example, 2011 https://hackaday.com/tag/helicopter-pov/
[kdf, Sep 27 2020]

Flicker vertigo https://flightsafet...hf/hf_mar-apr04.pdf
Lighting the entire underside of the rotor might be a bad idea [kdf, Sep 27 2020]

Rotor tip lighting on CV-22 https://theaviation...v-22-flying-saucer/
[kdf, Sep 27 2020]

And from Popular Mechanics Magazine - in 1947! https://books.googl...%20lighting&f=false
[kdf, Sep 27 2020]

Why old photos are in black and white https://www.gocomic...ndhobbes/2014/11/09
Bill Watterson explains... [kdf, Sep 27 2020]

Cyclogyro https://en.wikipedia.org/wiki/Cyclogyro
Theoretically, a good idea ... [8th of 7, Sep 27 2020]


       Bun, but easier to just project an image on it no?
doctorremulac3, Sep 26 2020

       Naw. You'd need to track it, compensate for distance, projector angle, yadda yadda. Much easier to incorporate into the blades themselves.   

       I keep picturing a stealth copter lit up looking like a UFO and blowing people's minds...   

       Nice. Curious as to the RPMs required for a POV display...
RayfordSteele, Sep 27 2020

       Not from the ground, a projector or series of projectors on the top of the helicopter shining up at the blades. That's just the price of the projectors and you could project anything without any programming. Movies, cartoons, prawnography (which is the study of the geometry of prawns) Put a big blinking eyeball on it or something.   

       Still like the LED idea though. Very weird it hasn't been done.   

       Could also use lasers.
doctorremulac3, Sep 27 2020

       In a word, apparently.
blissmiss, Sep 27 2020

       It has been done on r/c helicopters (link).
kdf, Sep 27 2020

       Coupling the electrical power up through the hub would be challenging, altho that can probably be done with a rotary transformer..   

       It's most likely a safety issue, in that for detail to be clearly visible to an audience, the chopper is going to have to be relatively low- at night.   

       Other than for landing, aviation authorities generally require a minimum altitude be maintained, particularly over built-up areas. There are the obvious exceptions for emergency services, winch rescues etc.   

       A Sikorsky S-61 has a main rotor diameter of 19m. For an observer to resolve details, they probably need to be within 150m or less. Flying that low at night isn't an issue to the pilots, because all helicopter pilots have a deathwish and are clinically insane, but it would be worrying (and very noisy) to those underneath.   

       Structures that stick up 20 to 30 m above ground level are far from uncommon. A small error could suddenly become very loud and expensive, and at such a low altitude there's no time to recover.   

       The fuselage is going to obscure a portion of the image. Fans with LED displays integrated into the blades have the axle at the back, so the full disc is visible.
8th of 7, Sep 27 2020

       ^ All of those things are true, but just to be able to light the ground beneath you like daylight while night landing as a pilot would make the whole shebang worth while.   

       [kdf] good find. I am actually surprised that none of those versions came up in my preliminary search.   

       Who are you working for?   

       Also - flicker vertigo (link) - another possible reason not to do this on a full size, piloted vehicle. At least not lighting the entire underside of the rotors. Even so, there are rotor tip lighting systems on some aircraft.
kdf, Sep 27 2020

       “surprised that none of those versions came up in my preliminary search.”
-2 fries shy of a happy meal, Sep 27 2020

       Funny! Just googling “led helicopter blades” turns up a lot like that.   

       “Who are you working for?”
-2 fries shy of a happy meal, Sep 27 2020

       I’ll never tell. I kidded with 8th a while back by implying Homeland Security, but that’s not 100% accurate.
kdf, Sep 27 2020

       Fine. Be that way. I get it, my authority won't allow me to disclose entirely either.   

       I googled led pov helicopter and all variations thereof... but I admit some of those searches were conducted here.   

       In my own defence I rarely search anything without finding reference to it here first... even as a last search.   

       I guess I must undo this long held assumption.
<heavy sigh>

       Everything changes.   


       “I rarely search anything without finding reference to it here first... even as a last search”
-2 fries shy of a happy meal, Sep 27, 2020

       i’m finding that sentence somewhat difficult to parse. But anyhow...   

       I always hit search engines here and elsewhere before posting my own “new” ideas. I’ve learned not to be surprised at how much that seemed original to me has really been done before. What does still surprise me is how snitty others get about being told their ideas were previously baked.   

       Not you, 2_fries, but others. I keep expecting someone to suggest making stop signs yellow instead of red - and then going ballistic when they find out stops signs used to be yellow.
kdf, Sep 27 2020

       // i’m finding that sentence somewhat difficult to parse. //   

       You're not the only one. Maybe he's channeling [wjt], or [Beanangel] ....   

       Search engines can be idiosyncratic and sometimes remarkably unhelpful. Frequently it's easier to post an idea, let others find the Prior Art, then delete it.   

       // used to be yellow //   

       Or indeed black and white. If you look at photographs from the 1920's and before, the stop signs are black and white; indeed, so are all the others. So that proves it, conclusively.
8th of 7, Sep 27 2020

       “Or indeed black and white. If you look at photographs from the 1920's and before...”
-8th of 7, Sep 27 2020

       Of course. The entire world used to be black and white. I read it online (link) so it must be true.
kdf, Sep 27 2020

       Ah yes, let me see if I can English that sentence a bit better.   

       Even if the hb is the last place I conduct a search for something it is usually the first place I find mention of that something, even when it is not widely known to exist.
Like a POV display on helicopter rotors.

       How's that?   

       Useless. Null points. Try again.
8th of 7, Sep 27 2020

       Would be more interesting to have an array of sliding panels on the rotor underside which slid in and out actuated by a mechanical cam type arrangement on the swash plate, so that there was a mechanical pov image created using purely ambient light.
pocmloc, Sep 27 2020

       You could combine that concept with a Cyclogyro <link> design.
8th of 7, Sep 27 2020

       //Coupling the electrical power up through the hub would be challenging//
Easy, slip-rings at the swash plate. I thought you were smarter than that, [8th of 7]. It's LEDs, so low power. Data can be the same or wireless.
neutrinos_shadow, Sep 27 2020

       Actually, you only need one slip ring, and use the mainshaft as the ground return.   

       That's not the issue, though; the issue is that it's "just one more thing to go wrong", something no helicopter needs...
8th of 7, Sep 27 2020

       We use hydraulic slip rings all the time in combat vehicles, so electrical can’t be that hard. Granted, those are ridiculously over designed and weigh half a ton and don’t spin several hundred rpms...
RayfordSteele, Sep 27 2020


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