sideshowmark Posted October 4, 2005 Share Posted October 4, 2005 I need to hang seven ceiling fans in a straight line from a fixed lighting grid as part of a set and have them drop in and out whilst turning very slowly, Ideally this would all be individually DMX controlled to allow my director to be as demanding as she likes! I'm struggling with the lifting mechanism as a chain hoist seems over expensive and overkill, I'd prefer something much subtler, simpler and cheaper. another option is hydraulics but I don't know where to start with this. Are they too noisy? - it's a small fringe theatre and a gnat's fart is deafening. Any thoughts? Link to comment Share on other sites More sharing options...
damian666 Posted October 4, 2005 Share Posted October 4, 2005 Bit more info needed really. I presume you have no flybars etc. would seem to me that some sort of wire hoist or 1 chain hoist put out of the way, via clew plate and pulleys etc to a few drop wires to a bar with them all mounted on it. Hydraulics far too over the top.as regards dmxing the lifting, don't unless absolutely unavoidable. DMX being a very unreliable medium. a person's thumb on a seperate button is the way to go!Speaking form postion as rigging company project manager if that helps!! just occurred to me your theatre is about 5minutes from my house! should come and visit really. Moderation note: unnecessary quoting of entire previous post removed Link to comment Share on other sites More sharing options...
dbuckley Posted October 4, 2005 Share Posted October 4, 2005 Just two notes a) Assuming bthese are "real" ceiling fans, these are a difficult load to control, I would not recommend that you plug them into dimmers. The way to control fan speed is by using series capacitors. Someone with electronic skills if pointed at my favorite rocket scientist's web site will be able to gain enough info to control them sucessfully. b) DMX is excellent for controlling mechanical things, it just isnt a safe protocol to allow such things to happen. One can combine the utility of DMX control with safety by having a deadmans handle switch operated by someone on stage, this should be a button that need to be held pressed to enable movement, and needs to interrupt motive power so you can be sure that when the switch is released motion stops. Link to comment Share on other sites More sharing options...
sideshowmark Posted October 5, 2005 Author Share Posted October 5, 2005 Thanx Buckley the capacitor-based speed control looks interesting, exactly how slow can it go? my designer was thinking of 5RPM but I'm worried about killing motors at that speed. Damian I have no flying bars just a smelly fixed grid. :) had the thought of installing one temorary bar to hang all seven fans off rather than individual telescopic thingies but I think it will be too ugly for the director/designer to deal with. My grid is at the grand height of 3.5M so anything below that just gets in the way. - please do pop in and say hi but bring your steelies - we use a lot of local volunteers - I can hear your laughter from here. I knew DMX was a bit of pipedream - I can't afford huge show crews so if it is all automated it makes my one stagehands life that little bit easier! anyone have any ideas how to build telecopic fan droprods that won't wobble all over the place? I hate to say no. Link to comment Share on other sites More sharing options...
dbuckley Posted October 5, 2005 Share Posted October 5, 2005 5RPM - that is slow. I'd replace the standard motor with a DC motor/gearbox assembly, it wont be easy (the motor supports the fan, its structural, as the fan is direct drive) but it converts an electrical problem to a mechanical problem. You can then run each of the motors off a transformer / rectifier thing (think train controller) and they are then dimmable on any decent hard fired dimmer, eg betapack. You might get below the dimmer's minimum load, so a small lamp (40W?) in parallel to act as a ghost load would clear that up. At that speed, there will be virtually no wobble, and as long as you ramp up and down gently there'll be very little torque reaction, so I'd try hanging the thing from wires, a triangle should do, probably end up almost invisible, fans suspended in mid air :-) Of course the wire can take the 12V for the motors too.... Only downside is that motor / gearbox will be noisiser than the fan's real motor, both audibly and electrically, so some experimenting may be in order. This sounds a fun thing to do. What is this show? Link to comment Share on other sites More sharing options...
Jivemaster Posted October 5, 2005 Share Posted October 5, 2005 Battery or mains mirror ball rotators? 4 ish rpm. Link to comment Share on other sites More sharing options...
damian666 Posted October 5, 2005 Share Posted October 5, 2005 mirror ball rotators, top idea that man!!Mark, I will PM re coming by. have a couple of ideas which may work, but need bribery with a pint to retrieve them!! Link to comment Share on other sites More sharing options...
sideshowmark Posted October 7, 2005 Author Share Posted October 7, 2005 Mirror ball rotators! genius. :) still struggling with the uppy-downy bit :) Link to comment Share on other sites More sharing options...
Jivemaster Posted October 7, 2005 Share Posted October 7, 2005 String over pulleys with loops and pegs in the required places, All tested for a suitable SWL in the range of 20 Kilos.(according to the weight of the "fans").Use two core wire and send the necessary 2 volts down the wire to power and control the motor. Get some FLAG cells 1.5volts and BIG and use them as counterweights. Link to comment Share on other sites More sharing options...
Dweeks Posted October 8, 2005 Share Posted October 8, 2005 As an alternative, you could use the "Fan/Nuclear symbols" supplied with most moving heads (250's etc), projected from the front onto the backwall/cyc? I'm imagining a warehouse scene, or something industrial, maybe you could use a suggest of the fans by rotating these gobos on the wall? Hiring a single rotating scanner/head won't break the bank, and has the advantage that its less risky than flying in those fans! Maybe if you need a wind effect from the "fan" (projected on the wall), you could permenantly hang a high powered fan to your grid, blowing onto the stage? Link to comment Share on other sites More sharing options...
mac.calder Posted October 10, 2005 Share Posted October 10, 2005 I have a fan gobo lying about somewhere - it 'feels' really good when combined with a really good whooping sfx (ie the sound those really big ventalation fans make that spin extreamly slowly) If however you NEED the fan visual, and have a static grid, get a rigger (may not need to in the UK, however in AU, you are meant to have your riggers license before installing any temporary rigging points) to create seven temporary hemp lines. The local black box that I have done a few shows at has a bunch of temporary rigging gear which we used to suspend a large neon sign from which was... fun. I imagine the principal would be much the same. Provided you do not need to move more than one at a time, you should be fine. The main thing is to make sure that whatever you tie them off to weighs more than the combined weight of the fans... again, experiance from the neon sign thing - we did not check and the result was quite amusing. A few sand bags later, all was well. If you have multiple different heights, it may be worth your while to buy a bunch of different coloured pieces of ribbon and make a bobbin (bit of tube, drill a whole, and stick the pointy end of a thick needle into it, weld the two together) and use that to place in a series of deads in the hemp. Link to comment Share on other sites More sharing options...
sideshowmark Posted October 10, 2005 Author Share Posted October 10, 2005 All seven fans slowly come in together for the entire hour and a half of the show, space is a long rectangle sunk below the audience in the round. trippy. Show is the Emperor Jones. Link to comment Share on other sites More sharing options...
sideshowmark Posted November 18, 2005 Author Share Posted November 18, 2005 WOW! Fan lifting gear installed by Damien666 most professionally! all works a treat - went for a chain hoist to seven ceiling fans via 90 metres of low rotation cable and a box-full of pulleys. First fans moves independantly. DMX control was abandoned after my dimmers burnt out his contactors and we ran out of time. Fans are running off wee 1rpm mirror-ball rotators as suggested by Jivemaster. BIG public thank-you to Damien for all his time and expertise - piccies to follow for those interested. Blue Room rocks I would never have done this without you all Link to comment Share on other sites More sharing options...
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