millie 12 floor hallway
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MarshallPope
Well-Known Member
When we did Millie last year, we did not have any problem with it swaying, as long as we flew it in just to the point where the bottom was resting on the deck, but without any slack. Are you using real doors? If so, that extra weight could make a difference. We built doors that were basically just artist canvasses in construction. To keep them closed, we just used sliding latches in the back.
The short answer is that you can't. You'll need to jack them somehow to eliminate that wobble. What can help is to increase the height and/or weight of the flats, but the former gets into designer acceptance issues, and of course the latter affects operation.
There are two reasons the wall sways when the doors open: 1) as the door swings out, the center gravity of the wall moves outside of the footprint of the flats and 2) dynamic forces generated by pushing and pulling the doors getting translated to the flat overall. Making the flats taller gives the doors a less favorable moment against the wall as a whole and against the lift lines. Making the whole thing heavier means that the center gravity will shift less since more of the total mass is staying in place, and will increase inertia which will help to dampen the dynamic forces.
But really, you want to jack the wall somehow. You can do folding jacks on the back that get stage screwed or sandbagged down, but this can wind up getting dangerous if not done right--ie, if someone leaves a sandbag on the jack, or doesn't secure the jack in its folded position before the unit flies out.
Another solution is to build a couple ballast wagons--just plain wagons loaded with a bunch of weight and a couple jacks that get wheeled into place behind the unit and latched to it.
And, okay, there is one other way to stabilize the wall without jacks per se--you could build guide tracks that the ends of the wall slide in.
There are two reasons the wall sways when the doors open: 1) as the door swings out, the center gravity of the wall moves outside of the footprint of the flats and 2) dynamic forces generated by pushing and pulling the doors getting translated to the flat overall. Making the flats taller gives the doors a less favorable moment against the wall as a whole and against the lift lines. Making the whole thing heavier means that the center gravity will shift less since more of the total mass is staying in place, and will increase inertia which will help to dampen the dynamic forces.
But really, you want to jack the wall somehow. You can do folding jacks on the back that get stage screwed or sandbagged down, but this can wind up getting dangerous if not done right--ie, if someone leaves a sandbag on the jack, or doesn't secure the jack in its folded position before the unit flies out.
Another solution is to build a couple ballast wagons--just plain wagons loaded with a bunch of weight and a couple jacks that get wheeled into place behind the unit and latched to it.
And, okay, there is one other way to stabilize the wall without jacks per se--you could build guide tracks that the ends of the wall slide in.
Anonymous067
Active Member
We had issues with this too last year.
Again, rest on the deck with no slack. If the doors won't stay closed, but a brace behind them to latch them when flown out. We also had the whole thing fly in with a door missing because it broke off when it was flying in, (and landed perfectly balance on top of two other flats...(we had to stop the show and retrieve it), because it opened up when it was flown out.
Again, rest on the deck with no slack. If the doors won't stay closed, but a brace behind them to latch them when flown out. We also had the whole thing fly in with a door missing because it broke off when it was flying in, (and landed perfectly balance on top of two other flats...(we had to stop the show and retrieve it), because it opened up when it was flown out.
