grins projector, recoil and test light builds

Very interesting. Would it be possible to take the following measurements for comparison:
a) LEP with only primary lens
b) LEP with RLT and only primary lens
c) LEP with RLT and both lenses?

Please :slight_smile:

I cant really take accurate measurements. One reason I have 3 W30s is I use them as my control lights. Other than that I like them I dont have a real need for one. however I am interested building my own LEP in a different configuration. But will require a different thread.
In the W30 underneath the window you see there is a about 10mm PCX lens with the belly out. I am not sure if it is there for one purpose or two but it will throw all your lens calculations out. Putting the rlt collar on makes it hard to focus because you are trying to reflect light back through a lens. And it is impossible to get the LEP into the collar any further.
that is where the secondary lens comes to the party It can be at half its focal length or closest to its lens to collect more light to direct to the primary lens.
You have to remember that something like blacking out the inside of the lens housing could give more noticable result than spending months trying to get more light.
To add to that I everybody has their own way of doing things and Im not having a go at you i can just be a little crude explaining things

Really thank you grin for taking the time measuring the prism mirror and collar! Much appreciated.

Some tips:

Stainless steel is not a suitable material for making a collar. A collar relies heavily on reflectance of blue light which re-excites the phosphor of the LED. Stainless steel has a low reflectivity in the blue part of the spectrum. Also, you need an actual coated mirror for max performance. Polishing a piece of aluminium will still not be good enough, but should be better than stainles steel. Wavien collars are dichroitic glass mirrors, those have around 95% reflectivity (or better).

If you want a pre-collimator that collects all of the emitted light of the LED and doesn't reduce the luminous intensity you need to use a short-focal length spheric (not aspheric) lens that you position right above the bare die of the LED (less than 1mm above it). See here for an example (it's in German).

mate wtf

coming up for a quick drive to check these out, chopped up w30 :o

Why should the pre-collimator be spherical? Not to mess with the asphericity of the main less?

I'm not sure in this case, it's just the experience of multiple people including me. These kinds of lenses always produced the best results.

* yeah first atempt was successful. I cut it by hand meaning I used a srcew driver to turn the chuck. Excuse the language but very rarely does something work with the first idea and the very first attempt. I havent tested it in a light yet but it gets a hot spot exactly the same as the one I brought. Now I can custom make the with fine tuned aperture.





I understand what you are saying about the materials, the stainless steel was laying around looked about the right shape so why not and It does make a visible difference to the beam.
Now that I know I can cut them I will look into silver plating. There are also places that can apply a protective coating. But what you are saying is it is in the actual glass. Well that makes it hard to reproduce at home then.

The small lens above the phosphor in the W30 is probably spherical then. I will have to have a closer look. You are obviously using it behind the collar which makes so much sense. The lense focuses the recycled light back and the collar provides the aperture. I had not got around to putting the lens directly on the led yet. Now you say that the W30 makes much more sense now.
Haha thanks for that, there goes another 6months

From my own experience i concluded the precollimator lens should be aspherical too.
Not sure why others conclude differently.
Maybe in between is best, i dunno.

The way I have it set up I call it the secondary. But I am going to have to look into having a 3rd lens or precollimator lens.

No, it's a precisely ground glass mirror (spherical) that is then coated with a dichroic coating. This type of coating allows for a very high reflectivity. To get similar performance for less money you can use a precise aluminium reflector that is then coated with an aluminium coating. This will get you around 90% reflectivity, close enough. The Wavien collar is slightly better, but with much higher production cost.

If you want the pre-collimator to be very effective it needs to be right above the LED so that it can collect all of the emitted light.

The_Driver, I understand what you are saying but if they are not available what else do you do? Myself I improvise and it is a hobby. The lights I build are to see if I can do it and to amuse myself, most of them I have no use for. But I do have an aim and that is to scale some small lights up as big as I can, not to break records or for any commerical purpose just for fun.
My Old Lumens comp light it is a prototype that I wanted to build I just didnt know how or if the idea I had would actually work. I have 4 BLF GT reflectors and 4 SBT-90.2 for a quad Im not sure about cutting the reflectors so I will build a few smaller ones first.

The information on the precollimator lens thanks it was very helpful. You are right about the spherical lens.

I found this actuator housing in the bin and I think I can make something cool out of it.


The 150mm lens is slowly getting a light engine this will have a K75 driver, SBT-90.2 and a marinebeam rlt collar. Lens is 150mm diameter and has a 177mm back focal length.




The battery tubes will go here but the back plate wont fitt in my lathe. Havent thought of a way to do it yet

Think I need a recoil thread

Can you get it done on a mill, or have access to one? an adjustable boring tool could cut out perfect holes for the batteries.

That brute is a beaut.

This stuff is impressive, very cool.
Love it when people experiment with throwers this powerful :smiley:

Yes yes….very cool….that recoil thrower looks awsome!!!

I have access to a big lathes at work but because it isnt my trade I cant just use them the tradespeople will freak out. I think the backplate will have to be changed or redone anyway. I could cut the battery tube mount off, cut the threads and then bolt that to the new plate. That is the way im thinking as weight doesnt really matter it is heavy anyway.
This is a copper piston for the led to sit on. the lights heatsink will be bored out for the piston, seals in either end of the barrel will contain the thermal compound and the piston will be driven by a leadscrew.


I have a week off so I will be self isolating and enforcing the get lost rule so I should get a bit done.
It is funny that recoil looks like garbage but will trow further than anything else I have w30 k75 gt. I made it like that because I damaged the reflector. But I cant stop there so I ordered the 24inch version from edmundsoptic. I also got rorted on ebay with an 8inch francis reflector. I think enderman posted the link on ebay to a glass mirror. So I had to have an 11inch with 6inch FL. The other day on ebay I randomly searched parabolic mirror and what do you know there is a 1940 era 36inch glass search light mirror 4hours drive from me. Made an offer got a bargain and I pick that up on tuesday.


Beamshot of 11inch glass mirror sbt-90.2 @12amp! w30 is on the right

Wow !! grin :+1:
I think you have taken the King of Big Lights title :wink:
Have you considered cooling the led in your 11inch glass mirror sbt-90.2 @12amp ?
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” Enderman ” cooled his like the pics below.

The SYNIOSBEAM - CFT90 recoil thrower pics start at #100.

The SYNIOSBEAM - CFT90 recoil thrower pics start at #204.

The SYNIOSBEAM - CFT90 recoil thrower pics start at #344.

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Could you please draw us a sketch on paper and I will transfer it to CAD and verify it thru a PM with you and then you can post it here for clarity reasons. I’m having a hard time putting your description together in my head. THANKS :wink:
. And one more thing Please, Where are you buying your lenses ??
BTW … GREAT BUILDS !!!
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