strobes versus flashers

Discussion in 'Instruments / Avionics / Electrical System' started by Jaysmiths, Jan 3, 2010.

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  1. Jan 3, 2010 #1

    Jaysmiths

    Jaysmiths

    Jaysmiths

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    Wow, strobe type nav lights are pricey.

    Do older airplanes use common light bulbs with flashers similar to those in cars for turn signals (I know the frequency of flashes is specified by the FAA)? I assume the flashers were phased out at some point, but when it comes to airplanes, one shouldn't assume ANYTHING. Could newer and brighter bulbs (xenon, perhaps) be used with flashers to increase the lumens?

    Somebody that knows something about this, your answer is appreciated.
     
  2. Jan 3, 2010 #2

    Dana

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    First, some terminology. Aircraft position lights do not flash. The regulations require steady green and red lights on the wingtips, and a steady light on the tail. These are the "navigation lights". Additionally, the regs require an anti collision light which is flashing red or white. Traditionally, the anti collision light was a "rotating beacon" (a bulb backed by motorized rotating mirror), mounted on the fuselage or the top of the rudder. Later aircraft used quartz halogen flashers when these bulbes became available. The bulb fit the same socket as a car flasher bulb but was about 20X brighter (so, to answer your question they didn't use "common light bulbs with flashers similar to those in cars".

    These were supplanted by strobes when solid state electronics made them possible, and in 1971 the required intensity for anti collision lights increased from 100 to 400 candelas, which presumably made strobes the only option. I also presume the requirement was increased because solid state electronics made the brighter strobes possible.

    Here's a good article on the subject.

    The "strobe nav lights" you're talking about are combination position lights and strobes, but note that the anti collision lights don't have to be in the same unit as the position lights.

    Aircraft strobes are expensive primarily because they're "aircraft" parts.

    -Dana

    Place a half full glass of water before a pessimist, optimist and an engineer:

    The pessimist says the glass is half empty.
    The optimist says the glass if half full.
    The engineer says the glass is too larger than it needs to be.
     
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  3. Jan 3, 2010 #3

    Jaysmiths

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    Thanks Dana, that is a great answer and very helpful.

    In FAR 23.1397, airplanes which received their type certificate prior to 1971 must have 100 candela minimum......I don't fully understand how this works.

    I'm building a BD-4 whose design dates back to pre-1971; does each experimental AC built receive their own type certificate from the FAA after appropriate inspections, fees, paperwork, etc or does the original type certificate AND DATE have any bearing on the requirements?

    Thanks again for your time and the egreat answer.

    js
     
  4. Jan 3, 2010 #4

    Dana

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    The BD-4 was never type certificated... an experimental doesn't have a type certificate; the date in this case is the date that your plane receives its airworthiness certificate. However, I don't know if the same standards apply to experimental aircraft.

    -Dana

    People are more violently opposed to fur than leather because it's safer to pick on rich women than biker gangs.
     
  5. Jan 4, 2010 #5

    djschwartz

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    An experimental aircraft's lighting must meet the same performance requirements as those of a certificated one. The only difference, and this can be a big one, is that you can use non certified lighting components in an experimental aircraft. But if you do, you assume responsibility for ensuring that those components meet the lighting performance requirements.
     
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  6. Jan 4, 2010 #6

    bmcj

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    For experimental, you can use some of the new non-certified LED systems (AERO-LED for example).
     
  7. May 9, 2014 #7

    Will Aldridge

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    I'm getting ready to build my rudder and realized I might need to put a light in it so I have been reading threads trying to find what kind of lights I need on my day VFR only airplane. And the answers I've found are somewhat ambiguous.

    Does the anticollison light requirement apply to experimentals? If so what does that entail? Flashing beacon and strobes? Direct references to applicable regs appreciated.
     
  8. May 10, 2014 #8

    TFF

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    Light rules do apply to homebuilts. Go high intensity LED. 20 years form now there will be no bulb replacements; everything will be LED. Search on this site as there was a post with the options a while back. no electrical system requires no lights.
     
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  9. May 10, 2014 #9

    bob noffs

    bob noffs

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    check out ztron. much cheaper than aviation stuff. their tail strobe is under $100.
    bob noffs
     
  10. May 10, 2014 #10

    Turd Ferguson

    Turd Ferguson

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    I flew a Beech 18 once that had a 3 position toggle switch for the navigation lights: OFF - STEADY - FLASH. That was how the plane was certificated and as far as I know there are still some airplanes that have that feature.
     
  11. May 10, 2014 #11

    Turd Ferguson

    Turd Ferguson

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    I flew a Beech 18 once that had a 3 position switch for the navigation lights: OFF - STEADY - FLASH. That was how the plane was certificated and as far as I know there are still some airplanes that have that feature. In FLASH mode all they did was turn on/off about 40x per minute.
     
  12. May 10, 2014 #12

    Pops

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    I had one of the first 1956 Cessna 172's that was built in 1955 that had the same thing. BTW-- Love the B-18's.
     
  13. May 10, 2014 #13

    Toobuilder

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    If you have enclosed wingtip lenses like many of the "fast" homebuilts do, then the navigation light can be as simple as a $2 bulb socket from the auto parts store and an $8 dollar LED bulb from the web. I removed the "certified" nav/strobe from my Rocket and went this way. Yes, the light pattern is specified in the FARs, but that is easy accomplish with bulb placement, paint masking and a little math. I have not measured the light output (also specified in the FARs), but I can tell you that the 80 element LED units put out a LOT more light than the units they replaced.

    As for the strobe, I already had the expensive aviation power supply, but I do use the automotive strobe bulbs used for show cars and emergency vehicles. A search of the web will show that automotive power supplies and strobe heads are significantly less expensive than the aviation products, and are often made by the same company.
     
  14. May 10, 2014 #14

    Aviator168

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    Do these lights apply to ULs?
     
  15. May 10, 2014 #15

    Will Aldridge

    Will Aldridge

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    Thanks for the answers guys. I'm going to go with the Diamondstar approach then (all lights on the wingtips). I would like to hear some thoughts on the safety of landing lights though. Since I don't plan on flying at night I don't need them but do you think there is a significant increase in safety by having one so the tower can see you better?
     
  16. May 10, 2014 #16

    Toobuilder

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  17. May 10, 2014 #17

    Will Aldridge

    Will Aldridge

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    I love it whenver something is repurposed and functions great. Could you show some pics of the mount and tell how you power it and switch it on and off ie bypass the switch on the flashlight itself?

    I just started looking around and found this strobe system and it looks pretty cool although the video warns that the LED's are highly directional so you won't be able to see them very far off axis. Can anyone point out LED strobes that will meet the FAA regs? Or is it less of an issue than I'm making it out to be?
     
  18. May 10, 2014 #18

    Toobuilder

    Toobuilder

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    This thread on VAF shows the setup. VAF Forums - View Single Post - New (October 2013) LED wingtip landings light discovered

    As can be seen this thread shows the dual, 3LED flashlights. Since then I have incorporated the "big brother" 9 LED unit on the other wingtip just to test them out. Both setups are very impressive.

    These are 5 mode flashlights that switch between modes if you cycle power within 2 seconds. In practice, it's easy to do from the cockpit. I run the "strobe" function for anti collision. "SOS" works well too.

    Edit: the first picture also shows my LED navigation light bulb.
     
  19. May 10, 2014 #19

    Toobuilder

    Toobuilder

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    Concerning the anti-collision requirements, they are pretty tough to meet with a home brewed setup. The 400 candela over the entire field of coverage is the main problem. Even the conventional strobe setups need the magnifying lens to get the light out to all the corners of the pattern. LEDS are coming on line in this regard, but the legal ones are expensive. Whelen, AeroLeds, and Avio come to mind as suppliers of these systems (but they ain't cheap!)
     
  20. May 10, 2014 #20

    fredoyster

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    That's right. But it's a lot easier these days, when you can buy high power LEDs bonded to aluminum plates, and prefocused plastic lenses that have a defined pattern, often with a lot of gain in one direction. Many of the white ones produce at least 100 lumens each, and combined with lens units that focus this down to 300+ candelas in one direction it wouldn't be too difficult to get to 400 with a little overlap.

    This topic should be a sticky somewhere, it comes up a lot. As usual it depends on what your operating limitations say. If you want to fly at night, your op lims will probably require compliance with 91.205 which says "approved" position and anticollision lights, which means the expensive TSO'd kind. For daytime, or if your op lims don't require it, you can use whatever you want. Ultralights require an "operating anticollision light visible for at least 3 statute miles" if operated during twilight.
     

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