Surefire K2 KROMA & KROMA Milspec

[Flashdark]

rgp4544,

Richard, what specific set of work requirements were you trying to satisfy, and did the light perform adaquately?? Mine was tactical/utility backup, so my review in Post #40 was probably slanted in that direction. We need to hear from more people like yourself. What was your need and how did the K2 work out for you??!! ("Inquiring minds want to know")

Flashdark sends.

 

[LED61]

TOY????? A lot of these comments have steam coming out of my ears.

Sometimes I wonder why people buy stuff they don't need...and I try to ignore reviews of lights from people who didn't need the capabilities but for some bizarre reason had more money than brains and had to run out and buy a new toy. Don't confuse compulsive shopping with need.

Keep in mind the Kromas were designed to meet a specific work related need and the need exists, it isn't just there for hobbyists to have a light with pretty colors. Some of us have an actual need and really aren't interested in buying another light unless it meets a specific need. Personally, I've ordered a Kroma Mil Spec to meet a specific set of work requirements.

Richard

Exactly right!!! we should not measure a flashlight performance based on lumen output alone, but for how well they meet the task they were designed to do. For instance, a live memory of a potentially dangerous situation dating back to around 1985 when I was in a cross country night flight in VFR conditions and I had an alternator failure in the piston single airplane. Well, the airplane's battery continued to put out power for the essentials but this only lasted for 25 minutes, after which I had me a complete blackout in airplane. I had a flashlight of course, not near the capability of the surefire Kroma or aviator or similar. And the flashlight I had served me well to illuminate my instruments thank God, but that capability came nowhere near what the Kroma offers now. I could have used the Kroma to preserve my night vision better inside the airplane with high red, and it is now a much better beam to do my 360 pleflight walkaround!! ideal light for a pilot,

 

[Flashdark]

LED61,

I too am a pilot, and I can't remember what color light will show up hydraulic fluid (hydraulic leaks) on the ground during a "walkaround". Do you know??!! Someone asked me if the K2 would be useful for this on "preflight" but I couldn't remember.

Thanks,
Flashdark sends.

 

[LED61]

Flashdark, the blue color would be the most suitable for this task.

 

[Flashdark]

LED61,

What does the hydraulic fluid look like under "Blue" light?? How does it show up??

Thanks,
Flashdark sends.

 

[LED61]

BTW Flashdark, I discovered a potential pitfall in using the rechargeable 17650. While the battery powers the light just fine at least in my case, and going back to the fact that it goes into the flashlight very tight and in a specific way, I accidentally dropped the light the other day and BAM!! all of the sudden no light. Turns out that the reduced length of the battery and the impact displaced the battery in such a way that it broke positive contact. So no matter how far I screwed the tailcap in it would not turn on. It was necessary to unscrew the tailcap, and press from the negative end until positive contact was reestablished. You would not want to mess around in this fashion in whatever emergency you needed the light for and so for serious use better use CR123's, or until I can figure out what sort of spacer I can insert in the negative end to insure there are no lose ends.

 

[Flashdark]

LED61,

Thanks for the info. I'll update Post #40.

Flashdark sends.

 

[LED61]

LED61,

What does the hydraulic fluid look like under "Blue" light?? How does it show up??

Thanks,
Flashdark sends.

WELL!!! I am not an airline pilot and hydraulic fluids are used mostly on jets, not pistons. But, hydraulic fluid is really hydraulic oil with some additives and depending on whether it is fresh out of the bucket or used it would turn slightly redish. Viscous redish fluids tend to contrast a lot with the blue light and its pretty much a black and white situation from there on. those type fluids also tend to reflect the blue light rather than absorb it. And keep in mind it would differ if your airplane was sitting on pavement-wet or dry or a concrete whitish ramp.
An airline pilot with this light in use would be better qualified to answer your question though. Sorry if all this is slghtly OT.

 

[Flashdark]

To All:

Post #40 has been updated to reflect CPFers attempts at "leggo-ing" the U2, K2, & K2MS into a "Shorty". See item #11, "Overall Conclusions", near the end of the report, for these results. In addition, the last two dozen posts in this thread have also addressed battery size and capability.

Flashdark sends.

 

[Chronos]

FWIW one can use the LU60 kit to enable the use of other C-body bezels and lamp assemblies on the K2/U2 bodies. I've been able to use setups such as:

KL5 + K2 body + K2 tailcap for 2-stage KL5
KL5 + K2 body + Detonator + K2 tailcap for extended runtime (2x17500) and 2-stage KL5
K2 Kroma bezel + A12 + K2 body (2x17500) + K2 tailcap for extended K2 runtime
M2 bezel + K2 body + SW02 tailcap for incan use

 

[rgp4544]

rgp4544,

Richard, what specific set of work requirements were you trying to satisfy, and did the light perform adaquately?? Mine was tactical/utility backup, so my review in Post #40 was probably slanted in that direction. We need to hear from more people like yourself. What was your need and how did the K2 work out for you??!! ("Inquiring minds want to know")

Flashdark sends.

Flashdark,

The standard Kroma appears to have been designed specifically for pilots and mechanics and since I could think of no use for the IR beam on the Mil Spec I switched my order to the regular red-blue-white one.

Right now I've only had a Kroma for a little over a day and am still playing with it to get used to the switching mechanisms - the switch is a bit more sensitive than an A2. I haven't really used blue light before but the Kroma really is the first really practical light I've seen that has both red and white low output and I've looked for 20 years for such a light. For the past two or three years I've carried two lights - one red A2 and one white A2 - and before then there really wasn't a single decent light on the market.

My needs if broken down are basically:
1) preserving night vision for which the low level dual output red is ideal
2) occasionally needing a very low output white light
3) preflighting an aircraft which requires some good white light, preferably dual output white light.

#1 generally requires an extremely dim low level red light similar to the Kroma's low output red because if dark adapted more light tends to erase details and you can't see a chart or a paper well if a light is too bright. Even the red output from an A2 Aviator is enough to cause a lot of glare to bounce back from a piece of paper. The Kroma's low output red is actually better than the A2's red.

Thus far the Kroma appears to be an ideal working light, although it is a bit large, and I think most pilots and mechanics would love it.

After I get used to operating it with one hand and after the tailcap twisty smooths out with practice I'll fly with it and can report on results then, because right now it seems too easy to flash a white beam.

I'm still not sure exactly how I'm going to carry this thing though...it needs an adjustable neck lanyard...

Richard

 

[Flashdark]

rgp4544,

I pretty much agree 100% with everything you said. Right now, I have a Z60 lanyard clipped to the pocketclip. I also sanded down the inside diameter of the 2-piece Z60 circumferential attachment ring and have that on the tail cap as a backup attachment point. I didn't want to use the Z60 with this attachment ring because the metal clip from the Z-60 scratches the tail cap when it rotates. (The attachment hole now sits so deep into the tail cap slot after the inside diameter was sanded down that the Z60 clip always seems to rub the tail cap when it rotates.)

This light has now replaced my U2 as my primary utility light. Right now, I am experimenting with an A21 + A12 combo for a "slimline" 2-battery version without the pocketclip. If I can use the Z-26 tail cap lanyard ring with this combo, I may stick with this.

Thanks for your input.
Flashdark sends,
Flashdark spends.

 

[rgp4544]

Flashdark,

I'm also trying a Z60 attached to the pocketclip and it appears as though it might be a functional solution.

The other item I want to try is just clipping the Kroma onto a Billabong nylon neck lanyard but I can't find where that lanyard is right now.

Richard

 

[Archangel]

Just a quick addition... Seems that, unlike the U2 (and like the Inova XO3), the Kroma won't regulate off of a single li-ion. Fresh off the charger, output using a 17670 was slightly less than it was using 2x123, but i was able to watch the numbers tick down slowly. The difference at first wasn't enough to matter, but things will only get "worse" over time.

 

[Chronos]

I'll back up this observation. I realized that with 1x17670 that I'm not seeing regulation. The Kroma does dim as the cell depletes. However, I saw a dramatic fall off in lighting level when my 2x123 primaries depleted. Interesting. Does the light have some boost converter that has a threshold from somewhere around 3v to 6v... below 3v (or so) there is no boost?

I'd like to test out the theory with my 2x17500s but I'm sending my light in for surgery.

 

[LED61]

I'll use my Kroma on my 17670 for play or non essentials. When I go flying, I'll make sure I have primaries. Try dropping the light guys and the battery will displace itself back and break positive contact. You will have to open the light and push the battery forward to regain it. Bad bad bad in an emergency.

 

[CM]

The Kroma uses a buck converter. With single Li-Ion, it will not regulate since Vf is close to cell voltage - diode drop. They're still using their low tech converters which are not of the synchronous type, hence you get a few hundred millivolts less than the cell voltage going to the LED.

 

[benighted]

I've had my Kroma a few days now. I like the extra capability of the colored LED's and the tightness of the white beam but I still like my white A2 better as my general use EDC.

The white A2 has brighter low and better high beam and a high beam runtime not much shorter than the KROMA.

I haven't had a whole lot of time to test it out in the real world but I'm leaving to Alaska on Friday so I'll have a good chance to use it in real world conditions. I'll report back here in about 2 weeks unless I can get service on my PPC phone then it might be sooner.

 

[rgp4544]

The runtime on the Kroma's high beam might be understated by Surefire, I've been playing with mine a lot to get used to the function and I think I may have used the high beam for over an hour.

Richard

 

[Flashdark]

rgp4544,

The runtime of the "High White" beam on the KROMA, as well as all other positions, is detailed in Post #40. ~1 1/2 hours of full power, followed by the power falling off to approximately "Low White" output by the 4-hour point. Power continues to fall off, and by the 6-hour point, you still have usable illumination if you select "High Red". Beyond this point, we are in "moon-mode".

Hope this helps,
Flashdark sends,
Flashdark spends.