From: Robert Donatz Subject: COZY: Cockpit lighting Date: Fri, 5 Nov 1999 17:17:21 -0800 I have some personal experience using "alternative" lighting in the cockpit. I don't have military experience, so I can't speak for the methods of the Armed Services. However, I have been quietly frustrated during my 21 years of night flying. I've always wished there was another way (other than resorting to turning on the white flashlight) to read the charts more easily. I'll admit to my pacifist nature and just accepting the red cockpit lighting. My awareness changed a few years ago and will never be the same. I was ferrying a friends Grumman from Missouri to Oregon a few years ago during the dark of December. I didn't stop for sunset and my flying went on close to midnight. Before my trip my friend gave me a sample of a flashlight he had just built up. It had red and green LED light bulbs in it. WOW, what a difference! It was like going from "formatted to fit your screen" to letterbox. Suddenly I could see the rest of the story on the charts. I will never go back to plain old red again. No more fatigue and frustration trying to squint out the magenta lines. Recently, this guy has added a blue LED to the flashlight and now I can see the yellows of congested areas clearly. It's remarkable how long we can get stuck in a rut and not ask "how do we get out of here." I've brought this flashlight to my EAA chapter meetings and get the same reaction, "wow, this is great" and "why haven't we done this yet?" So, the bottom line to all this espousing is that red and green LED's let you see so much more. When you add a blue you get the effect of "white" light. His little light is about the size of a pack of cigarettes. Even with all three lights selected, it isn't powerful enough to deteriorate your night vision (you can still see around you after you shut the light off). One other thing I like about this flashlight and LED's is their solid-state design. They are much more reliable and need much less battery. How I'm going to apply this in my MK IV is to use standard lighting for the panel and use the three-colored LED's on a hard-wired flexible post for accessory/chart lighting. As for the details of how this works, I'll let Dan, a pilot and experimenter, explain. (Disclaimer: I'm not an ophthamologist or expert, this is just what I have been able to deduce from books and studies of the subject over the years). If you look at a response curve showing the response of the human eye to different colors of light, you find that we are least sensitive to red and most sensitive to blue. This is the reason that red light was chosen long ago to "preserve night vision." But this response curve is misleading. The real killer of night vision is INTENSITY, not color. That is, a BRIGHT RED light wipes out night vision worse than a DIM light of ANY COLOR. But the red-night-vision connection is woven so tightly in to aviation, that it's been kind of a sacred cow until recently. A few years ago, the military began using a blue-green mix for night operations, and this forced us all to take a new look at the traditional red-only rule. The other problem with red (or any monochromatic (single-color) light) is the color differentiation problem: sectional chart magenta airports fade away, important notes printed in red become invisible, and should you suffer a scratch (as one commenter noted), you can't see the blood! A dichromatic light (a mix of two colors) greatly increases color differentiation, though it does not let us see "true" colors. For example, the blue-green light of the Gamma3 flashlight makes almost any color visible, except for a very narrow range of blue-green. Reds and magentas stand out strongly on a white background, but they appear dark gray, not red. To achieve both differentiation and true color perception, the light source has to contain all three primary light colors, which are red, green and blue. To sum it all up, for preservation of night vision, use a DIM light of any color; for color differentiation, use at least a two color mix; for perception of true colors, use "white" light. I put "white" in quotes because there is a huge range of mixtures of red, green and blue that the eye (or really, the brain) will perceive as "white." Of course, all of this is what led to the design of the Gamma3 flashlight--red for the classic night-vision protection, blue-green for best color differentiation, and white for true-color perception. You can read about the Gamma3 flashlight at www.gdi3.com or call 503-598-8079 and request a data sheet. Dan Date: Sun, 31 Oct 1999 22:39:55 -0400 From: kent ashton Subject: Re: COZY: instrument panel illumination I made some post lights out of radio shack #276-066B high-brightness red LEDs (470mcd). I haven't wired the panel yet but I've experimented with them and I think they will be just fine. Hardest part was making a hood for the LEDs. I made the posts out of 1/4" soft alum tube with a piece of 3/8" tube flared to form a hood and JB-welded into place. They look like little aluminum flowers that bend back at a 150 deg angle to shine on the instrument. I plan to just drill a 1/4" hole where I want them and lightly glue them in position. About $2.50-$3.00 each in materials. I like the LM317 idea. Bob Nuckolls also discusses this in his Aeroelectric book. --Kent A. dewayne morgan wrote: > > About 3 or 4 weeks ago, someone discussed a rheostat to dim the instrument > panel lights. Has anyone considered using red LED's. A simple and > lightweight circuit using a LM 317 voltage regulator and a potentiometer > and a few resistors would work well and use little current. Also, the > lifespan and weight of LED's and ponentiometer vs. glass bulbs and > rheoststat would be another consideration (I think I have only replaced 6 > led's in 15yrs of electronic repair). I have used/abused a LM 317 in a > homemade power supply for 10 yrs and it is still doing fine. LM317's are > good to 35 volts and have short circuit and overload protection built in. > > Dewayne morgan > > cozy #815 chptr 4 Date: Tue, 02 Nov 1999 20:57:34 -0600 From: David Domeier Subject: Re: COZY: instrument panel illumination Bulent, re "Dim white will be the best." There was a time when night fighter pilots sat around alert shacks lit with red light. Red lights improve night vision very much. In those days, all instrument panels were lit in red. dd Date: Tue, 02 Nov 1999 22:00:30 -0500 From: Jim Sower Subject: Re: COZY: instrument panel illumination I personally value my night vision more than the red markings on the instruments. I am supposed to know where they are anyway. Landing and taxiing at night I want my vision to be 'the best that it can be'. If I'm going to trade it away, it will have to be something a lot more important to me than the red instrument marks. Just a theory, Jim S. Bulent Aliev wrote: > Blake Mantel wrote: > > > dewayne morgan wrote: > > > > > About 3 or 4 weeks ago, someone discussed a rheostat to dim the instrument > > > panel lights. Has anyone considered using red LED's. > > > > Why red LED's? > > I would not use red lighting for the instruments. Red light will make all red > markings appear white. > Dim white will be the best. Date: Tue, 02 Nov 1999 23:02:46 -0400 From: Bulent Aliev Subject: Re: COZY: instrument panel illumination David Domeier wrote: > Bulent, > > re "Dim white will be the best." > > There was a time when night fighter pilots sat around alert shacks > lit with red light. Red lights improve night vision very much. In > those days, all instrument panels were lit in red. > > dd You are right about that Dave. I have spent countless hours in the photo dark room lit with red light only. Once had a bad cut from the film and was bleeding all over the place, but did not see it since the blood did look colorless. Try reading chart under red light and all red and purple colors almost disappear. If the instrument lights are hidden and dimmed, very little light will reflect from the black faces. I don't think the dimmed lights from the dash in the car affect my vision much? IMHO since the instruments have red limit zones marked in red, have them disappear may not be a good idea? The rest of the lights used inside the cabin should be red. On the other hand I still want to hear from some real pilots what's the best instrument lighting. Date: Tue, 02 Nov 1999 23:19:21 -0500 From: "L. Wayne Hicks" Subject: Re: COZY: instrument panel illumination David Domeier wrote: Red lights improve night vision very much. In > those days, all instrument panels were lit in red. -------> But red light makes red lines disappear. If I'm not mistaken, most military ops are going with blue-greenish interior lighting. Oh, and the helo guys use night vision goggles! Wayne Hicks From: TRCsmith@aol.com Date: Wed, 3 Nov 1999 00:04:05 EST Subject: Re: COZY: instrument panel illumination In a message dated 11/2/1999 6:59:08 PM Pacific Standard Time, david010@earthlink.net writes: << re "Dim white will be the best." There was a time when night fighter pilots sat around alert shacks lit with red light. Red lights improve night vision very much. In those days, all instrument panels were lit in red. dd >> But today studies have shown that red lights cause fatigue to the eyes. Now most all aircraft use white lights for instruments. tom Date: Wed, 03 Nov 1999 08:01:31 -0500 From: Paul Krasa Subject: Re: COZY: instrument panel illumination At 21:02 11/2/99 -0400, Bulent Aliev wrote: > > >Blake Mantel wrote: snip >> >> Why red LED's? > There were a series of human factors studies done by the military back during WWII which showed that red light has the least degredation effect on night vision. My panel has all white light on it because the instruments came with white lights and the miniature eyeball cockpit lights which are sold by Spruce and Wicks. The miniature eyeball lights are great. All of my engine instruments have backlighting, so I the only part of the panel which needed lighting was the standard six flight instruments. One eyeball light on each side of the interior and about 1' back lights the panel of my Long EZ perfectly. I got the idea from a friend of mine who used the same concept in his Cozy III except his eyeballs were mounted in the canopy. The minature eyeballs are a simple solution, (IMHO) elegant, and low cost solution to cockpit lighting. A miniture cockpit eyeball light is half the cost of one post light. Paul Krasa Long EZ 214LP p.s. Project status: Flying, Flying, Flying ..... There comes a point in test flying your airplane that no matter how large the test area is, its just not big enough. :) Date: Wed, 03 Nov 1999 23:10:59 -0500 From: Blake Mantel Subject: Re: COZY: instrument panel illumination "Monk, Dave" wrote: > > Blake Mantel asked: > >Why red LED's? > > Blake, > > The red lights do not destroy your night vision. In astronomy, we use red > lights to look at charts etc and our computers and RA/DEC readouts are all > in red, and we can still see the stars clearly. It has something to do with > rods and cones in your eyes. Since I am not a doctor, I do not know all the > details but I do know it works well. The red lights in your airplane will > preserve you night vision every time you scan the instruments. > Dave > MK IV #831 Sorry Dave but I cant open the pod bay doors.... ;-O (couldn't help it, just watched 2001) Well, this is just one of those things that people have always believed in and followed for the wrong reasons. Like hot water freezes faster than cold water for ice cubes, etc. Only recently has the data been widely disseminated to overturn this long held belief. But a dim yellow-green or white light is the best for viewing dials, etc. and not destroying much of the night vision. It does make sense that an instrument is most efficient in the middle of it's operating range. Later, Blake -- CUM CATAPULTAE PROSCRIPTAE ERUNT TUM SOLI PROSCRIPTI CATAPULTAS HABEBUNT. (When catapults are outlawed, only outlaws will have catapults....) Triumph Tiger Motorcycle page at: http://www.tiac.net/users/blakem/ My Email address is altered due to the prevalence of bulk Email senders. To send me mail remove the two *'s before the TIAC.NET. Date: Wed, 03 Nov 1999 10:52:57 -0500 From: Blake Mantel Subject: Re: COZY: instrument panel illumination (red led's dewayne morgan wrote: > I have always heard that red light doesn't impair night vision (as bad as > white light). I will need a little help here with more experienced pilots > as i have only 42 hrs toward my ticket . Green is also supposed to be good > for reading maps and also doesn't impair night vision. Blue LED'S are > expensive and are not very efficient (at giving off light) and i think > they also aggravate an astigmatism. Many years ago at Oshkosh I walked into a avionics tent discussion and was surprised to find out something that I had wondered about for years. The speaker was talking about a study commissioned by the USAF that analyzed night vision vs. cockpit lighting. It turns out that the use of traditional red instrument lights actually reduced night vision. This was due to red light being at the outer limits of the visual range and our eyes don't focus it very well. So the pilots would turn it up bright enough to clearly see the instruments and destroy their night vision. And the yellow green lights were used at the lowest levels by the pilots. This is logical, since the center of our visual range is in this area and it is an area of maximum energy as received from the sun. So it is the frequency that our eyes process at their best. Going back and attempting to remember some of my A & P studies (No, in this case it stands for Anatomy and Physiology!!!) the low light "night vision" chemical is a dark purple color. Any ophthalmologists on the news list and could advise here? And thus absorbs any light except for that wavelength of purple light. So red, green, blue, etc. lights are all absorbed and cause it to break down. So the least light is the best light and that is in the yellow-green area. BLUE LED's: As to blue LED's there is a newly designed doping procedure that should improve the yields of the produced LED's. That is one of the reasons that the prices are so high is that they have to junk so many of the units. Also the current LED designs suffer from a fast (well this is a relative statement) degradation of light output. A nice bight blue LED will be a pale ghost of itself 1000 hours later, bummer. Also, this new mix will slow the degradation as well in operation. Later, Blake Cozy Mk4 Plans #0008 -- CUM CATAPULTAE PROSCRIPTAE ERUNT TUM SOLI PROSCRIPTI CATAPULTAS HABEBUNT. (When catapults are outlawed, only outlaws will have catapults....) Triumph Tiger Motorcycle page at: http://www.tiac.net/users/blakem/ My Email address is altered due to the prevalence of bulk Email senders. To send me mail remove the two *'s before the TIAC.NET. From: ArlenBell@aol.com Date: Fri, 5 Nov 1999 20:40:30 EST Subject: COZY: LED Cockpit lighting For all of you chasing this subject take a look at the following web pages. http://www.americaworks.net/lighting/ http://www.americaworks.net/lighting/cockpit.html http://www.americaworks.net/lighting/low-voltage.html -- Arlen Bell Date: Wed, 03 Nov 1999 09:24:56 +0200 From: "Rego Burger" Subject: COZY: Night vision Any medical guys on our group to add to this discussion? 2c worth.... If the idea is to be able to see all instrument markings including RED ones then using a red light is going to defeat the object. I think night vision ( viewing outside the cockpit ) requires the pupil ( of the eye) to have a wide opening in order to gather the low light intensity, now any bright light in the cockpit will cause the pupil to reduce in size.... every adjustment is stress and makes life a bit difficult. So I would guess that any light inside the cockpit red or white, should be set at the lowest intensity as possible to avoid rapid pupil changes. If a candle worked in years gone by then maybe even a light with an orange tint would work fine as long as it was not set too bright. Having flown at night some, the red "old" system does take a bit of getting used to.... but even modern cars have adjustable panel lights, and they are white! Anyone have an idea if the frequency of the light has anything to do with the eyes response? Régo Burger RSA Date: Wed, 03 Nov 1999 11:51:48 -0400 From: Al & Bev Sweeny Subject: COZY: Night Vision Strongly echo dd comments. Another 2c worth from ex-night fighter p, present heavy jet civil p. We needed the red cockpit lighting to save our night vision when looking for targets and maneuvering heavily (in fact in two seaters I'd turn all lights OFF and let the GIB (guy in back) be the gauge monitor.) We masking-taped the undimmable warning lights and were careful not to mark maps in red or blue inks - black was always best. This was Vietnam era technology, the present systems may accomodate night vision concerns better. Today, though, civil night vision need isn't so critical, and amber, dimmable lighting systems work fine without having to doctor maps and charts. For me though, the plan is simple - no single engine Cozy night flying. Al Sweeny , Cozy 823, Prebuild From: N64DW@aol.com Date: Sat, 6 Nov 1999 02:14:39 EST Subject: Re: COZY: Night vision Builders, I have been flying Army helicopters for the past 14 years, with 700-800 hours flying low level night (25 to 200 above the highest obstacle). Lighting in them was red, back in the late 80's they changed over to blue/green lighting for aircraft that use night vision goggles. The reason for the change was that the red lights shut down the goggles due to their sensitivity to the red side of the spectrum. The Apache helicopter sill uses the red lights because we don't use goggles. The red lights don't effect your night vision as will white or even the blue/green. The red light doesn't effect your peripheral vision as will the blue/green. Blue green will seem overly bright when viewed off center where red will not. When viewed directly the red will be brighter than the blue green. As you know most of your night vision is in the peripheral. There should be an FAA pub that explains how the eye works. As for instrument markings being washed out by the red light. You should know the where limits are marked on the gauge by position, so when the needle points to that position you need to do something. Another thing that is a must for night flying is, blind cockpit drills. That means you should be able to put your hand on any switch, lever or knob required for flight without looking. Another thing that would be wise is to have different shaped switches for critical systems, so you can feel which switch your fixing to move. CW3 David West Apache Maintenance Test Pilot Comanche Base Bosnia From: "Doug Shepherd" Subject: COZY: Night vision & LED's Date: Tue, 2 Nov 1999 21:14:57 -0800 Builders, As I understand eyesight, the eye's sensitivity to any particular wavelength is reduced by exposure to that wavelength ONLY. If you use red light, your ability to see dim red objects will be reduced, but your ability to see dim objects of other colors will be mostly unaffected. But this works with any color -- a dim green light will work as a night light also, and won't spoil your dark vision except in the green band. Red is used mostly for traditional reasons; red is used in darkrooms because black & white film isn't sensitive to red light. You could make the argument that red vision is more important in the cockpit because of sectional shadings and instrument markings, so maybe a different color light would be preferable. Sectional markings can simply disappear with the wrong choice of lighting. LED's are monochromatic light sources, which means they won't spoil your night vision too badly. They also draw much less current than light bulbs and essentially never burn out, so they're not a bad choice for panel illumination. Since they don't draw much current, you could just use a potentiometer as a dimmer (fewer parts, better reliability than with a regulator). Because of the chemical properties of the materials involved, red LED's can be made brighter than any other color -- the third brake light on most new cars is made out of LED's. Next brightest is amber, followed by green and blue. Bright enough LED's of any color are available that you can make a flashlight out of them, but they're more expensive in green or blue (not very expensive in any case!). Watch out for narrow angles; to get the most light out of their LED's, the manufacturers focus them into a cone as narrow as 7 degrees for some LED's. A super-narrow LED like that has a higher brightness spec and makes a good flashlight but a really lousy area illuminator. I would suggest amber for panel illumination. You can crank them up to surprising brightness at full rated current, sectional markings should be relatively decipherable, and I find the amber light far more pleasant than red. Green or blue would be okay except they're more expensive and just won't give as much light as amber. You might also play around with two colors at once (bichromatic). Bichromatic light can appear nearly white, so sectional and instrument markings will look almost normal, but it will affect your night vision more than monochromatic light. Doug Shepherd From: "Doug Shepherd" Subject: COZY: Night vision and LED's Date: Tue, 2 Nov 1999 21:22:01 -0800 Or is that dichromatic??? From: "dewayne morgan" Subject: COZY: panel illumination Date: Tue, 2 Nov 1999 23:51:15 -0500 I have always heard that red light doesn't impair night vision (as bad as white light). I will need a little help here with more experienced pilots as i have only 42 hrs toward my ticket . Green is also supposed to be good for reading maps and also doesn't impair night vision. Blue LED'S are expensive and are not very efficient (at giving off light) and i think they also aggravate an astigmatism. From: TRCsmith@aol.com Date: Wed, 3 Nov 1999 00:07:44 EST Subject: COZY: re.instrument panel illumination << re "Dim white will be the best." There was a time when night fighter pilots sat around alert shacks lit with red light. Red lights improve night vision very much. In those days, all instrument panels were lit in red. dd >> But today studies have shown that red lights cause fatigue to the eyes. Now most all aircraft use white lights for instruments. tom From: jhocut@mindspring.com Date: Wed, 03 Nov 1999 08:59:53 -0500 Subject: COZY: Re:Night Vision / instrument panel illumination >There were a series of human factors studies done by the >military back during WWII which showed that red light has >the least degredation effect on night vision. I recently attended a night vision training class put on by the Navy opthamologist who developed the program for the Navy, (and as I recall was adapted by all our armed forces as well as the Isreali armed forces). Anyway, the new concensus is to use dim white light. It takes our eyes about 30 minutes to fully adapt to darkness, and once adapted a suitably dim white light doesn't seriously degrade our night vision. Jim Hocut Cozy IV #448 - ch 19 From: ArlenBell@aol.com Date: Wed, 3 Nov 1999 10:23:18 EST Subject: COZY: Re:Night Vision / instrument panel illumination This is my first post so if I've screwed up the message by not following proper format, please let me know -- and bear with me. Regarding Night Vision and light colors, I certainly second the idea of using a full-range dimmer and white lights. Sometimes we NEED to see the instruments more than whatever might be outside and being able to control the light level is important. I as I recall from my father in WWII, one of the reasons red light and night vision was so important was that the planes often flew with no marker lights and there was little if any lighting on the ground/runway--bet you know why! If someone wants to play around with it, there are now LEDs which give off a white light. Also if one is really into absolute maximum night vision, one can go with two types (white & red). Personally, I don't see the need for the red lights -- just keep the white lights at lower levels for normal flight. Remember the Nav lights you may be looking for are red/green -- you don't want to reduce your acuity for either by running a red or green lit cockpit. But someone asked the question about light color. Red has been covered thoroughly so I'll address only blue and green (incandescent or LED-- doesn't matter). The eye is most sensitive to green light -- if you need to know the exact wave length, I can send that to you, but again -- it doesn't really matter. STAY AWAY FROM BLUE! Blue light is the least efficient wavelength handled by the eye. Blue light has one advantage -- it can be seen well in peripheral vision (wonder why those taxiway lights are blue). However, the eye has a difficult time focusing it. I wouldn't use blue for any general lighting in the cockpit. I think it's been said best, stay with a light source which will allow you to read sectionals and see the instrument makings -- just keep it low -- with a full-range dimmer you can go all the way down. -- Arlen Bell Date: Wed, 03 Nov 1999 09:30:36 -0600 From: David Domeier Subject: Re: COZY: Re:Night Vision / instrument panel illumination Jim, re "Anyway, the new consensus is to use dim white light." I'm sure you, Bulent and the US Navy are correct....I was just rattling the cage on how things were long, long ago, before radar and all the magic stuff we have today, when fighter pilots had to have good night vision to stay alive. Fact is, before I left the USAF in '67, red was no longer the standard in cement. I flew many a all-night flight in my "junior" years with an airline and "dim white light" is by far the least fatiguing. It seems the eye muscle is most relaxed when the iris is open. I know for a fact that bright light, which keeps the iris opening small, is very fatiguing. I flew with an old geaser on international who kept the lights up bright all night, probably 'cause he was afraid of the dark, it was very hard on the eyes and your entire system. I'm not much on flying single motor, experimental airplanes at night. Especially a take off. Ending a cross country after dusk is OK, but that critical 3 minutes after take off is no time to be dark. If anything goes wrong, you're going to get hurt. As a matter of accident record, a most risky approach is night VFR without a glide slope or VASI. It is very difficult to judge the visual slot unless you're intimately familiar with the slope of the runway and local terrain. A steep runway slope can screw you up in day light, not to think about it at night. dd Date: Wed, 03 Nov 1999 18:46:35 -0600 From: Michael Link Subject: Re: Fw: COZY: panel illumination extensionsystems@mindspring.com wrote: > Just a thought. > > The best looking and most eye friendly panel I ever flew was on a rebuilt > Beaver Float Plane. > > This panel used a black painted plastic cover that at each instrument and a > reversed chamfer. The light was "Injected" with screw in bulbs from the > front. At all switches & breaker the name was engraved through the paint. > > The effect was breathtaking, Just a slight glow of red that you could adjust > up or down. > Hi, I have the above described system on my Cozy. Not a new idea really....the 50's vintage B-52's and KC-135's that I was so intimately associated with while in the U.S.A.F., had the same system. The results, are still spectacular. Regards, Michael Link COZY MK-IV N-171-ML From: cdenk@ix.netcom.com Date: Wed, 3 Nov 1999 21:23:51 -0500 (EST) Subject: Re: Fw: COZY: panel illumination If one notes the angle of the inside of the plexiglass bubble, and angles of incidence and reflection of the light from instruments, it understandable how nearly all illuminated instrument panel objects will reflect off the plexiglass at near to below pilot's eye level. Have thought about extending the panel cover aft to shade the instruments, but it will project something like 6" aft of the panel to be effective. Instruments include King KX-155, and internal lit VOR, White post lights on unlit instruments, JPI slimline LED readouts with dimmers. All instruments are on separate dimmers (electronic similar to Bob Nuckolls) for each type illumination (Post light, internal, etc.) if not self dimming. Chart and clipboard illumination is by "Littlelite" gooseneck with dimmer base mounted forward face of arm rest pocket, they set nicely over your lap, totally out of way of hand/arm movement, stowing against the fuselage inside skin.