On Wed, 2013-06-26 at 09:26 -0500, Stuart Stevenson wrote: > I thinking hologram. Then the crash would appear real with breaking and > crumpling and everything. :)
Nice if you can carry it off. Complete with sound effects? Dave > > > > On Wed, Jun 26, 2013 at 8:53 AM, John Kasunich <[email protected]>wrote: > > > > > > > On Wed, Jun 26, 2013, at 05:29 AM, Erik Christiansen wrote: > > > On 26.06.13 01:30, Gregg Eshelman wrote: > > > > If you're near a coast or large/deep lake you might find a deal on a > > > > used electric downrigger. Load it up with 300 pound test line and > > > > there's your mechanicals, just need to figure out how to brake it to a > > > > stop at the right moment without breaking things. ;-) > > > > > > Careful; 200 pound chandelier x 1.5g deceleration = 300 pound force. > > > > > > By the time that a visually acceptable sharp deceleration is achieved, > > > and a good safety margin is allowed, we might be up around 6000 lb or > > > more? > > > > > > > Exactly! I was thinking about that last night while walking the > > dogs (after I sent my earlier message). > > > > Some numbers: suppose you start with it 20 feet above the stage, > > let it "free fall" until it is 4 feet above the stage, then decelerate to a > > stop at stage level. > > > > First the free fall. Gravity is 32 feet per second squared. That means > > in the first second it will go from zero to 32 feet per second and fall > > 16 feet, winding up 4 feet from the floor. To bring it to a stop in four > > feet would require decelerating at 128 feet per second squared, and > > it would stop in 0.25 seconds. That deceleration rate is 4 gees, so > > if the chandelier weighs 200 lbs, you will need 800 lbs of force to do > > the job. > > > > At the beginning of the decel, you have 800 lbs of force and a > > velocity of 32 feet per second. That is 25,600 ft-lbs per second. > > One horsepower is 550 ft-lbs per second. So you need a 46 horse > > power servo to do the braking electrically. Not gonna happen on > > any reasonable budget. > > > > The force at the pulley is higher than the cable force. If the cable > > turns 90 degrees at the pulley, it is 1.41 times higher, if 180 degrees > > it is double. So the 800 lbs becomes 1100 to 1600 lbs. That is > > half to three-quarters of a ton. So you need a very strong pulley, > > and a very strong place to anchor it. If you would be nervous > > hanging a car from your anchor point, you better not hang your > > chandelier on it. > > > > I think the very first thing you should do is try to figure out how > > to make the chandelier as light as possible. It is a stage prop, > > not a real article. Can it be made from materials that are lighter > > than brass and glass? Can you use bright amber LEDs for the > > "candle" flames? Can you make the prisms out of clear plastic? > > Can you stylize it a bit? Maybe a very light frame, LEDs inside, > > and artfully folded and arranged clear or silvery (or both) mylar > > film to get the same "gilttery" effect? I think some out-of-the- > > box thinking could make a "chandelier" that weighs 10 or 15 > > pounds, which would completely change the nature of the job. > > > > Good luck! Let us know what you come up with - this is an > > interesting challenge. > > > > > > -- > > John Kasunich > > [email protected] > > > > > > ------------------------------------------------------------------------------ > > This SF.net email is sponsored by Windows: > > > > Build for Windows Store. > > > > http://p.sf.net/sfu/windows-dev2dev > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > -- > Addressee is the intended audience. > If you are not the addressee then my consent is not given for you to read > this email furthermore it is my wish you would close this without saving or > reading, and cease and desist from saving or opening my private > correspondence. > Thank you for honoring my wish. > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
