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Red Alert Tesla project

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Tesladownunder

Wed Oct 10 2007, 01:14AM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

Marko wrote ...

Neighbors aren't problem for you as far as I see, at least if your mmap is correct.
BTW, wouldn't it be easier for you if you just talked some of your sons/friends to pose in costumes than to build gawky dummies? :D

Sheep pass by that fence at times and I have some kangaroo shots a few feet from where the engineer stands. I don't expect they will hang around.
I need to use dummies because all of them will be too close to the sparks, besides I don't have many 4 foot family or friends. I need them small to try to keep the scale reasonable.
It is raining now but the weather will be OK for shooting on Saturday so if I have enough hands available I will probably be ready.
I need to get my rotating filter organised to have a yellow filter in the field 25% of the time to get the occasional yellow sparks. I can remove the mild yellow cast later but I prefer to have zero post processing at all so I might need a flash at the start to give a normal background color.

The shot at this stage is looking like 30 seconds. There will possibly be a flash to start, then 5-8 seconds to pull the wire through to get the sparks from the Tesla trooper and around the coil. Then the long wire needs to be drawn out for the 30 feet over about 20 seconds and the exposure needs to end there without too much delay. That means a manual start and stop to the shutter with IR remote to avoid bumping the camera
Oh, and the video needs to be running as well.

Lighting is another issue since parts of the toroid are very reflective and it is preferable for the light to be diffused. I usually use a 150W halogen directed on to a 4 foot diameter white polystyrene foam disc. This is fine for just showing sparks but I think I need to show more of the background here. I will start with some natural twilight first.

Typically I take a few shots then download them to try to work out what needs adjusting like lighting, focus or exposure. Focus is set prior to the shot then fixed at the best distance so the camera is not hunting around in the dark trying to focus. It can do that but not with sparks flying. I will focus just past the coil but the target will be quite a bit further away. It is not as important to have tight focus there anyway.

Lots of other issues that might be important on the day such as droop of the wire over 30 feet. Not a visible problem over 19 feet though. I might just do the first setup at 20 feet. It will be better for focus and framing anyway. I can't use too much tension for fear of pulling the coil over but I might be able to put a nylon stay behind the coil to support it. Tension will also bend the coil and blur the outline. Sparking to the ground is another issue and I may need to elevate the target even higher.

Pic shows the target. This is just a cardboard cutout on a wood frame covered with sheets of white A4 paper. Paper fluoresces under UV (remember the nitrogen laser) so it shows up as bluish colour with the sparks plus fluorescence. I am not sure that it looks the best but is not too dissimilar to the Red Alert representation. Often a skeleton like look is used and maybe that is what was intended but in limited pixels wasn't able to be done in the game.

1191978518 10 FT32031 Teslaratargetsparks

Tesladownunder

Sat Oct 13 2007, 01:18PM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

Problems.
Had a full day working on things today.
Sorted out the balancing of my yellow filter. Works nicely but has not been tested on sparks yet to see the effect. It could easily get washed out if there are too many sparks.
Corrected the spacing of the multiple toroids and improved the base stability.
Sorted out the Tesla trooper wire. In theory it was good as were the preliminary pics but wire tensioning is a problem and with my brake (a bit of wood on the ground pulled by the nylon line) it was a bit jerky. As a result the line dropped too close to the secondary and flashed over on to the secondary with resulting damage and arcing between windings. In addition the previous damaged area has broken down again so I now have 3 arcing turns on the secondary. This is not good but is repairable in an ugly sort of way but will take time.
Picture below shows a long exposure with a close up of sparking at the base. These are not racing sparks.

The wire for the long sparks was made far too long (measured at 34ft) and again had a tensioning problem resulting in too much sag. Also, it pulled the coil way out of tune, more than I recall before but I guess it was nearly twice as long. Tensioning could be achieved by using a separate brake. I will have to think about that.

So I now have to do a major repair on my secondary and do more design work before I can consider any other runs.
I have my open day in 2 weeks so I need to repair the coil for then and also prepare displays etc so the Red Alert project is on hold at present. Hopefully some action in 3-4 weeks.

TDU

1192281383 10 FT32031 Teslaratrooperfullsetupsparks1000

Firnagzen

Sat Oct 13 2007, 01:31PM

Registered Member #567 Joined: Tue Mar 06 2007, 10:55AM
Location: Singapore
Posts: 147

Sad to hear that, I was looking forward to the result!

The coil looks good! But perhaps you should cut down on the distance between the supports and the secondary. That gap looks a bit too wide...

Ctrl+D...

Tesladownunder

Sat Oct 13 2007, 11:42PM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

This is the camera with diffused flash and rotating yellow-orange filter. When it is running, one in 4 sparks will be yellow. The flash shot and the Tesla trooper shots will not be colored so I should not need to alter the yellow balance.

1192318836 10 FT32031 Teslarahalforange600

Tom540

Sun Oct 14 2007, 04:46AM

Banned on 3/17/2009.
Registered Member #487 Joined: Sun Jul 09 2006, 01:22AM
Location:
Posts: 617

Just when you thought you've seen everything.......

Fessenden

Wed Oct 17 2007, 02:38AM

Registered Member #687 Joined: Mon May 07 2007, 02:21AM
Location:
Posts: 14

Great Job! No matter how much everyone professes the seriousness of the science, I think all of us got into this at least a little bit because of the "evil-giggle factor".

I have heard many electrical/electronic engineering people say they got into their fields because of school demonstrations given by Ken Strickfadden in the 50's and 60's. His demo's were art tempered with a little science.

Is the next step a twin bipolar TC "Red Alert style"?

Dr. Slack

Fri Oct 19 2007, 09:23AM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

Impressive work TDU. A suggestion, as people will continually accuse you of photoshopping the images, direct them here --->

http://xkcd.com/331/

(don't forget the hover)

Tesladownunder

Fri Oct 19 2007, 10:44AM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

A good idea. XKCD is a great place to spend/waste hours.
I will however have lots of intermediate construction photos and outtakes and a video. Already the page on my site is getting big. Most people are believers when they see the site though.

I will be able to do some work on the setup and coil repair this weekend but the weather is probably against me for a full shoot.

I might have to accept a shorter spark length to give the picture a reasonable aspect ratio and get around the tuning problem. I will have time to experiment though.

TDU

Tesladownunder

Sun Oct 21 2007, 02:23AM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

Secondary repairs. Cut and rejoined in 3 places. Gaps are uneven as the winding seems to slip on the polypropylene.
Had to make a motor drive to rotate the former while drying.
Uses an old 100VAC motor with a reduction drive, a solder reel and a strip of bike tyre.

TDU

Sulaiman

Sun Oct 21 2007, 09:52AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

Ha Ha ! .. I tried a teflon primary - drove me NUTS ! soooo slippery.
Polypropylene is also very slippery
- all the potential/theoretical benefits of a low-loss former are lost by a layer of varnish!

Nice to watch your project progressing Peter, I just LOVE the things you do with TCs !
can't wait to see how many hits / gigabytes you score once published!

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