Turbohead: More flood or less?

cfromc

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I've never had a Surefire Turbohead and am looking at building a light but I need to decide whether its going to have a KT series head or a smaller C-series head. I'm looking for good flood and the Turboheads give me some good options for HOLA lamps, something like a N62/MN61/MN21. How do the turboheads compare to the C-series heads for flood?
 

nzgunnie

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The KT heads produce a more focused spot, but, they tend to have more powerful LAs, the upshot of this is that especially inside, the flood simply from the amount of light bouncing around is considerable.

Outside will be different, you will notice the throw and tighter spot more outside, and may find the KT heads are not the best for you if you want flood.

Of course you could get the diffuser that fits the KT head, I'm sure running one of the LA's listed it would produce a lot of flood. Not sure about heat build up though?
 

cfromc

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mdocod said:
Go with a Leefbody 2x18650 with C head/tail and a P91 lamp. This will give you insane amounts of flood.

And based on your chart, that is about 390 bulb lumens, which is about 310 torch lumens, low risk of instaflash although possibly shortened bulb life, still a good sized body, small head, rechargable, 45 minutes run-time. The other option is the 3x18650 with turbohead=large body and head, up to +/-750 bulb lumens, 40 minutes run-time, and a little more chance of instaflash. hmmm...I already have an ROP that is on the edge of what I'd call something I'd like to carry around a lot, the first option I could get a holster for, looks like I'm leaning towards exactly what you recommend mdocod. Although, if Mark @ LF comes out with that 1000 lumen M-series 13V lamp............:whistle:
 

yellow

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dunno if this has changed now (my Sfs are some years old):
the Turbo has just an extremely concentrated spot, not the usual medium flood.
 

mdocod

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my chart is talking torch lumens fresh off the charger, roughly 390 torch lumens fresh off the charger... in "SF" lumens it would be about 310... if you wanted a number that you could compare to the "200" they list for the P91 on CR123s.

The reason for this is several fold:
1. SF underrates beyond T-lumens, the P91 is closer to 250 torch lumens on CR123s.
2. 18650s maintain significantly higher voltage under a load. fresh off the charger into a 2.7A load, 3.8V is pretty easy, that's 7.6V for a little while.
3. CR123s sag to about 2.225V under a load of 2.5A

apply re-rate formula: 7.6V/6.675V=1.1386, 1.1386^3.5=1.575. 1.575x250=393.75 torch lumens.
 

scott.cr

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This "setup" might not interest you but I figured I'd throw it out there anyway. The Surefire U2 has the most beautiful, smooth flood of all the lights I own.

On the other hand... if you want a Turbohead, Surefire makes diffusers that latch over the Turbohead, and these also produce a great flood pattern. The bonus is when you want to spot something in the distance, you can slip off the diffuser (it's easy).
 

cfromc

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mdocod said:
my chart is talking torch lumens fresh off the charger, roughly 390 torch lumens fresh off the charger... in "SF" lumens it would be about 310... if you wanted a number that you could compare to the "200" they list for the P91 on CR123s.

The reason for this is several fold:
1. SF underrates beyond T-lumens, the P91 is closer to 250 torch lumens on CR123s.
2. 18650s maintain significantly higher voltage under a load. fresh off the charger into a 2.7A load, 3.8V is pretty easy, that's 7.6V for a little while.
3. CR123s sag to about 2.225V under a load of 2.5A

apply re-rate formula: 7.6V/6.675V=1.1386, 1.1386^3.5=1.575. 1.575x250=393.75 torch lumens.

So the P91 in front of 2x18650s will be about 55% brighter than in front of 3 123s? 310/200 (or 393/250). That's a good start because I'm just not that impressed with the P91 w/3 primaries. Maybe I have a bad bulb but mine's not THAT much brighter than a P90. (or did I get the math wrong and it is 310/250=24%)
 
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Size15's

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This is the MN11 lamp in the M3 bezel:
P55.jpg


This is the MN16 lamp in the Millennium TurboHead bezel:
P56.jpg


Whilst these are not my photos, they are a reasonable representation of the difference between standard and TurboHead beams.
 

cfromc

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Thanks Size15's, we can always count on you to have beamshots and pictures of different lights with head/body/switch combos. I like the top beamshot better for my general all-around light. Now I have to decide between an M3 head or a C series head.
 
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