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

No, you’ve made a good point.
But he already knew it, and so he put a disclaimer in his post saying exactly what you mean.
Though, if he would tweak his design to suit the reflector it would only be some minor tweaks. So not a big deal imo at this point (which is all about outside design)

Alright, I’ve redraw my design so I could run a thermal simulation. Here is the result:

As I said, I’m not sure how accurate it is since this is the first time I did this. However i think this give us a good representation about how it will perform.
This is with a 40watt load distributed along the led shelf. Imaging that the MCPCB will evenly distribute the entire 40 watt load on the shelf.
Thermal convection coefficient is 20W/ (m^2.k), I really dont know what that means but its a good number for natural air convection. (like walking around outside I guess)
Ambient temperature is 300 kelvin around 30 degrees celcius.
I’ve run another simulation with a convection coefficient of 50W/ (m^2.k) and that gives a 20 degrees celcius difference (cooler).

Yes, really.
But not for this project. :wink:
Could be a great mod though.

It was just an example to help with realizing that size matters.
Small adjustments of something well balanced won’t be too hard, but keeping the length down helps quite a bit over time.

I’m glad we agree.

Forget the buts.

And this simulation confirms what i was saying a few sites before.

Building PC heatsinks and watercooler for more than 10 years (as an hobby) is helping a lot when you try to figure out if a thermal design will work. :stuck_out_tongue:

We are still going with the 120mm reflector. No precolimations.

In this 120mm light we can add a small lens, to focus the spill forward, and gain a significant percent of the light towards the corona.

Just throwing some relevant performance ideas out there. Instead of discussing 20 pages for 3 fins or a notch. :slight_smile:

If you want performance i would say recoil reflector set up.
Problem though, is finding a decent and affordable 5 inch reflector that can take at least 120° from the LED.

No lenses, but if you show us how to make it float I am sure we are all very impressed and Penn and Teller might want to know it too :wink:

Just kidding, lenses are for another project not the GT.

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Penn and Teller. :smiley: :smiley: :smiley:

K.I.S.S (keep it simple stupid)
especially when we are making a BUDGET flashlight, i don’t want a cheap Chinese len, the quality is very poor

When popcorn alone just won’t cut it… add a soft drink of your choice. :+1:

:smiley:

Thanks thijsco19, that is informative not to mention just downright cool. :+1:

:slight_smile:

So basically it looks like from the thermal simulations that the current design is just enough to keep an XHP35 cool enough to not burn you. Anything more and it will get too hot and need to step down. So we for sure need to keep cooling in mind as night time temps here in Texas can be easily 90f+ which would allow it to get even hotter.

Good info!

As far as the reflector goes, 5AR has not had a design to work with since we do not know what we will be using yet. That said I really like the shape he has come up with anyways, the strong taper to the head just doesn’t do it for me, looks a bit silly IMO.

There will naturally be some redesigns once we find a reflector.

And remember, this simulation is done with a convection coefficient of 30 W/(m^2.k), which is natural convection (almost no moving air/no forced cooling). If you would walk outside that number will increase, and that has a big impact on the results. (increasing the number to 40W reduces the temp by ~5 degrees celcius)
Also the battery tube isn’t part of the simulation, so that increase the mass which will reduce temps slightly.
And finally you hand plays a big role in cooling a light (well only if you’r not waring gloves but in the winter the temps are low enough that it wont have problems).

So I think that the cooling is good enough. Maybe some small tweaks.

It is good enough, I am not saying any major changes but we for sure don’t want any less cooling. The extra fins in 5AR’s last design is about the most I think would be needed.

Wow, they all look good!!!
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My favorites are 5ar’s V0.5 & MortyDuck’s V0.45 (the combo version of 5ar’s V0.4 & V0.5)
Tough choice…… :slight_smile:

I agree, my favorites are the .45 and .5 as well, hard to pick between them.

I think I like the .45 better myself but based on others in this thread I think the .5 will have a wider appeal.

Given time I think the .5 will grow on me as well.

First, I’d like to point out that not all parabola’s are created equal. There is no fixed parabolic formula for flashlights, which is why 200 flashlights on my shelves all have different profiles. There is simply no such thing as perfection. It all starts going wrong when we leave the pinpoint of light at the source and spread out the die surface, that gives us multiple points of output and the parabola suffers when trying to converge the beam.

The Nitecore P30 is a nice example of being different, at approximately 43Wx40D it approaches that “square” ratio and as such it throws very well for a smallish light, illuminating out at 670M with a mere 1070 lumens from an HI. I’m not prepared to cut my TN42 reflector in half so you can see an example of a thrower’s parabola (approx 89Wx88D), nor am I willing to cut the SR-90 Intimidator’s as it too can do over a mile…. and at 88Wx60D it’s more of a bowl than you’re describing as perfect. At any rate, having had several different lights in hand that attain a mile throw, I can tell you for a fact that each one had a different parabolic formula.

All we can really do is wait and see what reflector is available for our need and test it to see how it performs. We just might not be able to get a proper reflector that does what we want. Not without designing it first.

I have a 200mm convection lens from Edmunds, it lists for $135 for the glass lens alone.

Conclusion is if you have more cooling fins you have more square area of cooling to the surrounding air. I think if the cooling fins can be cut deeper. And they have a bigger diameter you will have the best result. Is it easy to do the thermal analysis again with wider cooling fins and in between the fins deeper milled (smaller diameter). PS I like the .5 style