Mirror ball drop

[Deathride]

im doing an fmp in college (the rink ) and these a methion of a mirror ball droping just wanted to know some health and saftey on the subject

[gareth]

Few questions ...

 

What's an FMP?

 

Do I understand correctly, that the proposal is to drop a mirror ball from height? Is this a controlled descent? Or will it be on some sort of 'snatch' line that stops it short of the floor? Or will it actually hits the deck?

 

And why does the title of this topic mention WYSIWYG? I don't see what that has to do with the question.

 

Please, in future use the spell checker (methion, saftey, etc.) and try putting a bit of punctuation in your posts.

[the kid]

FMP is final major project. Supprised that your asking now if its a Btec there is only 4 weeks left of term.

[djw1981]

My interpretation is that OP wants a mirrrball hidden behind say a truss (suitably draped) which descends for a specific effect and then returns to behind the truss. I have seen this done several times, often in the middle of 'sserious' music performances. The descent was so the punters did not see it at first entering the theatre.

 

The WYSIWYG reference I assume to be how one would show this in a WYSIWYG design.

 

I may be totally wrong.

[mac.calder]

A mirror ball is just like any other flown object. As long as it is well designed, and flown in in a controlled mannor, there should be no problems. Most mirror balls I have worked with are extreamly tough anyway, so a bump along the way in or out will not cause it to shatter and 'rain glass upon the masses'

 

How are you flying it in? Straight Up/Down, or pulling it on an angle so that it flys in from behind something? If you are angling it at any point as a unit (ie including motor), make sure that the joint between the ball and motor is a closed loop, not a hook (as a number of cheap, small mirror balls are), so that when you fly it back out for the next show it does not slip off the hook..

[Deathride]

ok the WYSIWYG stood for what you see is what you get ... The plan we have is that the mirror ball is going to be attached by actors ( ECK ) and then raised vertical and dropped there is going to be a rope with a knot in to stop it falling however we have no flight access so were going to use pulleys after the drop it will be pulled back up so :D by the sounds its all ok to do it which is good was worried it might not have been

[djw1981]

Ah....the actors attaching it could be the problem. A whole world of are they competent to do it. Perhaps you need to start with a nice risk assessment of the procedure - is it teh same person each time, how long do they have to ensure it is secure before it is flown out, is that area of stage going to remain clear until the mirror ball has been secondarily suspended etc.

[gareth]

ok the WYSIWYG stood for what you see is what you get ... The plan we have is that the mirror ball is going to be attached by actors ( ECK ) and then raised vertical and dropped there is going to be a rope with a knot in to stop it falling however we have no flight access so were going to use pulleys after the drop it will be pulled back up so  :D  by the sounds its all ok to do it which  is good was worried it might not have been

<{POST_SNAPBACK}>

Still doesn't really help much.

 

We know what WYSIWYG stands for - it's one of the best-known software packages in the lighting industry. What I don't understand is what it has to to with your question.

 

So, let me try to understand what you're saying. A mirror ball is going to start off at ground level, attached to a line of some sort by one of your turns. It's then going to be hauled up into the air, and then released so that it drops. It's going to be supposedly prevented from hitting the deck on its descent by a 'rope with a knot in'. Riiiiiight. There are many concerns here, but the main one is that you expect a mirror ball that's effectively in freefall to be 'caught' by a knotted rope attached, presumably, to the normal suspension point on the mirror ball. Have you even considered the fact that when the falling ball reaches the 'stopping point' as determined by the knotted line, the shock load applied to the attachment 'twixt ball and rope is going to be many times the weight of the ball itself? With respect, it sounds like you don't really understand the implications of what you're thinking of doing.

 

Still decided not to bother with punctuation, I see ..... :o

[Jivemaster]

If you can prove that the plan, its implementation and execution will be safe at all times then you can consider doing the effect. So far the design statement is imprecise so I guess the method is imprecise also, therefore more design work is in order.

 

What size mirror ball are you hoping to use? pass 12inches and they become heavy and expensive.

 

Talking of Mirror balls. Try this its 2.8gig zip file

 

http://70.84.44.58/downloads/AlienSong_Download.zip

[peternewman]

Talking of Mirror balls. Try this its 2.8gig zip filehttp://70.84.44.58/downloads/AlienSong_Download.zip

<{POST_SNAPBACK}>

Interesting, and vaguely relevant to the topic.

 

[Pedant Mode]

The file is 2.8 Megabytes or 0.0028 GB.

[/Pedant Mode]

[Just Some Bloke]

ok the WYSIWYG stood for what you see is what you get ... The plan we have is that the mirror ball is going to be attached by actors ( ECK ) and then raised vertical and dropped there is going to be a rope with a knot in to stop it falling however we have no flight access so were going to use pulleys after the drop it will be pulled back up so  :D  by the sounds its all ok to do it which  is good was worried it might not have been

<{POST_SNAPBACK}>

 

Does that translate as:

 

"OK: WYSIWYG stands for "what you see is what you get". The plan we have is that the mirror ball is going to be attached by actors (etc.) and then raised vertically and dropped. There is going to be a rope with a knot in it to stop it falling. However, we have no flying bars so we're going to use pulleys after the drop (it will have to be pulled back up). So, it sounds like it's OK to do it, which is good. I was worried it might not have been."?

 

If so:

 

1) WYSIVYG reference still unclear.

2) The actors (etc.) will need to be shown how to attach the ball safely.

3) What are you using to raise the ball in the first place? How strong is it?

4) How does the rope come to be attached?

5) The rope with a knot in it will be seen, surely?

4) How strong is the rope? See Gareth's point about the load applied when the ball suddenly stops

5) How do you avoid the ball hitting someone while it's falling and before the rope has caught it?

6) Later posts should have made you think again about it all being OK. There is an in depth risk assesment to be done first, if you ask me.

 

I'm sure there will be a way of doing it, but you need to be careful you've covered all your bases first. BTW, if you're ever hoping to become a Production Manager you should think a bit harder about how you communicate ideas with others!

 

Good luck.

[mac.calder]

I think you would be better off doing this in a much more controlled fashion than a knot stopping the fall.

 

1) Actor correctly attatches ball to line.

2) Back stage hidden flyman pulls the ball up, whilst actors use a mock up, or a secondary line joined to the main line.

3) When actor 'releases' the rope (or whatever is meant to happen), rigger does a controlled fall, hopefully at a steady, slower speed.

 

If you want to fiddle with some figures, in an ideal world, your velocity at the end of a fall (from a stationary point) can be calculated using v^2=2AX (A=Acceleration due to gravity - 9.8m/s, X=Displacement - how far it falls). From the final velocity, to work out the force that will be applied to the line, newtons second law - F=MA - (Force=Mass x Acceleration) - note that the acceleration is equal to v in the above formula - you are accelerating at that instance from the final velocity to 0. These of course do not take into consideration friction, air resistance, line weight and a multitude of other factors.

 

If something is going to fall, you need to have control over it. Once the rope is let go, chances are there is no way to 'hold' if something gets in the way - a flyman will hopefully be wearing protective gloves, and the rope should be running through his hands at all times, so in the event of the unforseen, a twitch of the muscles, and the ball stops.

[Chris_R]

I would also go for the fly man idea as Mac said in his post above. My main concerns (as above) would be what would happen of someone got in the way once it had been let go? Who would stop it? could they stop it? Will the rope hold it? etc.

[djw1981]

An alternative I have seen done, but which requires a little more sorting is to use a motor (in this case a lodestar 1T) which was fastened onto the grid, which long distance controls so it could be controlled by a crew member who could see the area around it was clear. Since it was not importnat to the action which cast member attached the mirrorball, and since there were 30 people on stage, on of the crew was persuaded (3 pints and a fancy costume) to go on stage for one scene and be in the crwod scene then attach it and come off at the next change. That way it was trained crew doing the attachment and the director got the effect he wanted.

[Andrew C]

It might be worth reading up on how the chandelier in Phantom is done. (Pulleys, hydraulics and a good design)

 

I'm sure it has been discussed here before somewhere; if not, maybe someone has worked the show...