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Searchlight construction help

A

Adam Aglionby

Jan 1, 1970
0
Michael Shaffer said:
Ok, I got a cool idea what to do with my 1500w MH bulb and ballast. I
want to make a huge searchlight. The only problem is where would I get a
mirror that would work? :( The mirror has to be concave right, not flat?

It has been done:

http://tinyurl.com/23nf6

http://www.fleetie.demon.co.uk/curt_searchlight.html

Mirror should be parabolic with the source at the focus, typical MH lamp`s
discharge is a bit big to get in the focus.
Xenon is most popular nowadays, though at least one company claims to have a
compact arc metal halide searchlight.

Carbon arc looks loads more impressive than even 7kW xenon, have seen side
by side comparison and carbon just has the Bat Signal look.

Years ago worked in a theatre that had Philips Auto Arc film projectors,
solenoid striking of the arc, motor feed and photo elctric cell monitoring
of arc length, guess it was about as advanced as carbon arc got.Also used
Sunspot carbon arc followspots which kicked sand in the face of 1kW CSI
followspots.
Here's a pic of what I want to make, although on a MUCH smaller scale.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=11762&item=2237313257&rd=1#ebayphotohosting

Petrol engine!? British ones are Lister diesels , wonder if this one has its
original engine and generator...?

Jasper Maskelyne, the great illusionist, used tin faceted reflectors
mounted revolving in front of searchlights to disguise the Suez canal at
night, the effect being a giant `moonflower` with multiple rotating beams at
aircraft height.

For modern searclights, try search for Spacecannon,Skytracker, Sky Cannon,
Synchrolite and Diablo amongst others.

HTH
Adam
 
A

Adam Aglionby

Jan 1, 1970
0
Apart from a troubled bid history....

These would be nice if you could get them re-silvered, rhodium plated metal
is more common nowadays, certainly a better bet than the 30" which is
probably too small for a decent effect.

Big arc lenght and small reflector equals lot of spill light, smaller source
is more at point of focus of the parabola.

Either use a snoot or spill rings to clean beam up a bit:

..http://www.revolux.com/Englisch/NV_Parabol/NV_Parabol.html

Adam
 
A

Adam Aglionby

Jan 1, 1970
0
Not comprehensive but a few of the current Searchlight makers:

http://www.francis.co.uk

http://www.searchlight.ie

http://www.skytracker.com

http://www.skycannon.com

http://www.spacecannon.com

http://www.syncrolite.com

http://www.spectrolab.com

Off the wall thought would be try an old satellite receiver dish
,polished.....

Adam

Michael Shaffer said:
Ok, I got a cool idea what to do with my 1500w MH bulb and ballast. I
want to make a huge searchlight. The only problem is where would I get a
mirror that would work? :( The mirror has to be concave right, not flat?

Here's a pic of what I want to make, although on a MUCH smaller scale.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=11762&item=2237313257&rd=1#ebayphotohosting
 
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