[PART 1] Official BLF GT Group Buy thread. Group buy officially closed! Lights shipping.

[teacher]

@The Miller

I assume only Dutch people know the saying “to step over ones shadow”
It means something like “make own lpreferences less important then those of the group”

I’ve never heard that one, but it is a good one. :+1:

I am familiar with the two below, they may be more of an American thing though.

• “Cast a shadow over (something)” - To dampen, spoil, or ruin something that was hitherto good or positive.

• “Take the shadow for the substance” - To accept something false, deceitful, shallow, or insubstantial in place of something true, meaningful, or valuable. In today’s modern, materialistic world, it is all too easy to take the shadow for the substance.

Water does seek it’s own level though, so I’m sure this will all work out just fine when the dust settles………

[The_Miller]

@DB Custom

I’m out.

Will simply make my own without all the drama.

Cool, as you wrote before you are comfortable with just making a superlight and then present it. This is indeed a completely different process, please post your findings along your way

[Koenta]

@DB Custom

I’m out.

Will simply make my own without all the drama.

Please make a post with updates on progress. We can all learn from that. We all want the best and are flashaholics. Maybe you are right about all the comment and arguments. But that is just part of the fun engineering this flashlight. I’m learning a lot reading these posts

[mdeni]

Are you very sure that you want 120mm reflector? Since it will be purpose built, perhaps a shallower 150mm could be better?

Shallower and bigger diameter should improve throw for the same cost?

[Enderman]

@Koenta

If we compare this

IM reflector

With above picture the parabolic curve doesn’t look right. The end of the IM reflector is almost straight.

I just made it to the dimensions I was told.
The IM reflector is definitely longer than it is wide, so it would be something other than 120x112mm.

[pommie]

@Koenta

With above picture the parabolic curve doesn’t look right. The end of the IM reflector is almost straight.

Go to this link,

Parabola - Interactive Graphs

slide the F button up and down, a parabola is based on a mathematical formula so for a given diameter there is only one depth for pure throw.

Cheers David

In regards to everyone having a say,

A camel is a horse designed by a committee

[Enderman]

@pommie

@Koenta

With above picture the parabolic curve doesn’t look right. The end of the IM reflector is almost straight.

Go to this link,
Parabola - Interactive Graphs
slide the F button up and down, a parabola is based on a mathematical formula so for a given diameter there is only one depth for pure throw.

That’s the exact same thing my functions do, except I made it so that the focus is always at 0,0 and the bottom part of the reflector (which is always unused) gets cut off so that you get the true height and width.

[mdeni]

@pommie

@Koenta

With above picture the parabolic curve doesn’t look right. The end of the IM reflector is almost straight.

Go to this link,
Parabola - Interactive Graphs
slide the F button up and down, a parabola is based on a mathematical formula so for a given diameter there is only one depth for pure throw.

Cheers David

In regards to everyone having a say,

A camel is a horse designed by a committee

Now slide the D button… And get any depth you want.

[Koenta]

I don’t want to say someone is wrong. It was just an observation that the IM reflector has not the optimal design, that’s it.

[Enderman]

@Koenta

I don’t want to say someone is wrong. It was just an observation that the IM reflector has not the optimal design, that’s it.

It certainly doesn’t look like it either.

[pommie]

@mdeni

Now slide the D button… And get any depth you want.

If you look close the shape is the same, regard that as a zoom

Cheers David

[G0OSE]

@teacher

@Texas_Ace

The issue here is time, that would delay things a few weeks at least and we were planning on proposing the idea to a manufacture soon.

I do agree that a poll such as this has all sorts of potential issues though.

I totally understand the time issue & completely agree with you.
I have my personal opinions about there even being a need for this poll… but that is not my call so I’ll keep them to myself.

But I’ll stand by this……… the “DESIGNER” needs to be nailed down first and foremost.
Also, I personally think that person needs to be capable of professional quality renders.

That is my .05……

You know, I wrote almost exactly this last night before the whole poll got mentioned, then deleted it before posting lol!
You are quite right about choosing a designer, that ‘person’ needs to be experienced in using/owning the appropriate software/skills for completing this task to the level the manufacturer will need.
So, design apart - you are correct, ultimately if ‘we’ (the blf) are going to actually design the light 100% then it stands to reason the person doing the designing/finished technical drawings is capable of doing so to a level that is sufficient to forward to the manufacturer.
As for choosing a finished design - well like anything in life peoples ideas are poles apart lol - whatever is chosen will not please all. Hell, why don’t we just photoshop both designs together and be settled!
We could rename it the ‘Jerommel 5AR’ - omg that even sounds like a Chinese flashlight ! :person_facepalming:

[Texas_Ace]

@mdeni

Are you very sure that you want 120mm reflector? Since it will be purpose built, perhaps a shallower 150mm could be better?

Shallower and bigger diameter should improve throw for the same cost?

120mm was never set in stone, since we had not found a reflector we could not do that in case something perfect but slightly different in size came up.

Although I do not want to see anything smaller for sure. a bit larger could work if the perfect reflector was found.

[AlexGT]

Here is a pretty good post by CPF member “The_Driver” regarding throw, he made last year on the other forum, credit goes to him…

I was actually looking for a parabola formula for one of Fivemega’s big reflectors, I know he posted it a long time ago somewhere but can’t seem to find yet

Anyway here is the post I found interesting…

Quote:
” My calculation was based on the assumption that all factors remain the same and the throwmaster had an outside diameter of 2.5 inches. As you say, 2.5 inches is actually the inside diameter. This makes a big difference (a little bit more diameter increases the area of a circle significantly).

For throw you need the surface area of the reflector as seen when looking straight at the light from the front (this is reason why the depth doesn’t have much effect on center beam throw) and the luminance of the light source. From this number you need to subtract a few things like transmission losses from the lens and the reflectivity of the used reflector.

The calculation is very accurate if the used data is accurate. We have been using it for years in the German TLF forum. Here is a very good explanation. Just use google translate since it is in German.

Here is is my new calculation:
We need to first calculate the luminance of the bulb, since there is no data for it.

Surface area of standard mag reflector (what is the diameter of the bulb opening of the kaidomain reflector?):
diameter large opening: 47.4mm
diameter small opening: 15.3mm
surface area: (47.4/2 * pi) - (15.3/2 * pi) = 1581mm^2

Surface area of throwmaster reflector:
diameter large opening: 64mm
diameter small opening: 12.5mm
surface area: 3094mm^2

For comparison - surface area of FM3X 3-inch reflector:
diameter large opening: 71.5mm
diameter small opening: 12.5mm
surface area: 3892mm^2

Now the lux numbers from bigchelis make much more sense. The throwmaster should double the lux value of the light.
I don’t have more time now. I will finish the calculation later.

EDIT:

*The formular for Throw is:
Beam intensity [cd] = reflector surface area [mm^2] * luminance of lightsource [cd/mm^2] * reflector reflectitivity ] * lens transmission [*
This is how you calculate the throw at turn-on. Led light tend to lose brightness because of heat (depends on how good the heat dissipation of the light is). This would be an additional factor for the calculation. Similarily incan lights without regulation lose brightness because the battery voltage drops continiously. Regulated incan lights should be perfectly constant.

I will now use this to calculate the appoximate luminance of the bulb in big_chelis light:
Luminance of bulb = 85,000cd / (1581mm^2 * 0.9 * 0.92) = 65cd/mm^2

Now I will calculate the approximate throw this bulb will produce with the Throwmaster head using the dimensions that fivemega posted:
Beam intensity = 3094mm^2 * 65cd/mm^2 * 0.9 * 0.92 = 166,519cd = 167kcd

Pretty dang close to the measured numbers .

Like I wrote before - for maximum throw the FM3X-Heads will be better, because they have an even larger diameter.
Beam intensity = 3892mm^2 * 65cd/mm^2 * 0.9 * 0.92 = 209,467cd = 210kcd

@fivemega: for throw only the surface area of the reflector as seen from the front actually counts. Depth does not make a big difference here. The one thing it can influence is the bulb hole diameter. Making it smaller will increase the surface area by a tiny amount. The diameter of the large reflector opening is the only thing that really makes a difference. Please remember though that I am only talking about the throw (center beam candela/lux). Not the shape of the beam or anything like that. For those types of things your deep reflectors seem to make a really big difference.

[treysoucie]

In for 1 of these. Thanks

[vol]

If the handle is going to carry 8 batteries but still work with 4 why is the tube not going to be two pieces?
Sorry if this has already been covered but this is a long thread.
I would prefer a two piece tube/handle.

[Enderman]

@AlexGT

@fivemega: for throw only the surface area of the reflector as seen from the front actually counts. Depth does not make a big difference here. The one thing it can influence is the bulb hole diameter. Making it smaller will increase the surface area by a tiny amount. The diameter of the large reflector opening is the only thing that really makes a difference. Please remember though that I am only talking about the throw (center beam candela/lux). Not the shape of the beam or anything like that. For those types of things your deep reflectors seem to make a really big difference.

I can back this up, you can see this effect when playing around with the graphing functions I made.
The amount of font area you gain by increasing depth decreases exponentially, you can see this on the large circles graphed below the reflector: Parabola - Height And Width Formula | Desmos
The area between the small and large circle is what will be reflecting light.

Also, the closer the surface is to the led, the more spread/diversion/corona you get from those parts, so the parts of the reflector very close to the LED actually do not contribute as much to throw as the outer/farther edges do.

[JockRobbins]

@vol

If the handle is going to carry 8 batteries but still work with 4 why is the tube not going to be two pieces?
Sorry if this has already been covered but this is a long thread.
I would prefer a two piece tube/handle.

One piece, 2 carriers. Leave one empty or fill them both.
Preference is taking a back seat to the desired design.
It’s a one piece tube, take it or leave it!

[Texas_Ace]

@vol

If the handle is going to carry 8 batteries but still work with 4 why is the tube not going to be two pieces?
Sorry if this has already been covered but this is a long thread.
I would prefer a two piece tube/handle.

Cost, balance and cosmetics. It will cost a lot more, be horribly unbalanced and looks ugly is the basics though.

[Jerommel]

@Enderman

@Koenta

I don’t want to say someone is wrong. It was just an observation that the IM reflector has not the optimal design, that’s it.

It certainly doesn’t look like it either.

It is a deep reflector, about as deep as it is wide, and then the parabola is almost straight at the large opening indeed.