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Originally posted by rrb_brick:
So, if you make a rod-bullet-thingy...with a wire hook on it that can fit into a grapple gun **Cough** Welrod**Cough** that has enough grip space or body to hold a spindle wit the wire, then your set.

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Originally posted by atxmaker:
First, Jamie's ascender: I thought it was spot on, very good for a short timeframe, proof of concept design. I couldn't tell from the video, but it appeared the transmission he used to step down the high-rpm motor was a set of stacked gears. If so, it may have been easier to go with a worm gear; that gives you the drastic reduction in rpm/drastic increase in torque, but in a smaller package with less contact friction loss. Plus, since in this case you don't need or want the power transmission to go the other way, it is a great way of locking the line without relying on the motor, and it allows you to offload the tension from the motor to the thrust bearings on the worm screw. One thing that supprised me was the size of the line used, and/or the line breaking. I would have thought that he would use Spectra, which has a 250 - 300 lb. working load at diameters thinner than cotton kitchen twine. With spectra, you could also decrease the takeup drum diameter for the same line length, which would increase the mechanical advantage (or, really, reduce the negative mechanical advantage by reducing the drum radius) and possibly allow for a smaller motor. Other easy addons to make it smaller given the time and money would be going with Litium Ion/Polymer batteries for increased energy density and possibly moving to an axial winding system (like a spinning reel for fishing, only with the spool instead of the bail turning) to make it more compact.

On Adam's grapple gun: This was one I felt could have benifitted from more definition of needs and more experimentation. Part of the failure of Adam's design was in the modification of the nail gun. 22 blank nail guns rely on a very high peak pressure over a very short period of time (the blank going off) occuring between an object with very little mass (the nail, which also concentrates its force in the small area at the tip during impact) and an object with a much greater mass (the nail gun apparatus + the hammer). It appears Adam stripped as much as possible off of the nail gun to get it to fly right, which would greatly reduce the force transferred to the nail and its ability to be driven into the wall. But even if it had successfully been driven into the wall, we were never shown in testing prior to the final that a properly driven nail in concrete would support the weight of a human (easy: concrete block, nail, put on forklift in workshop, see if Adam can hang from it). To make matters worse, using it the way he did (taught zip line config, tied at both ends) is even worse, because even though the line is tied at both ends, each end is actally pulled *more* than it would be just holding his dead weight alone. Back of the napkin calculations based on what's listed in the Backstage Handbook on bridling lines says that if we assume Adam to be 250lbs or so, the pull on each end of the line would be half that, or 125lbs, *times* the multiplication factor based on the degree of deflection between the lines to the load (Adam) and a straight line drawn between the end points. The smallest angle listed is 10 degrees, with a multiplication factor of 5.76. That means if the line between the tie-off and the nail in the wall was fairly taught initially, at the point Adam stepped off the platform the loading on the nail in the wall was probibally *at least* 720 lbs. For any anchor to have held in that zipline config, it most likely would have had to have been able to hold a verticle dead load (load parallel to nail axis, not perpendicular) equivalent to both Mythbusters, the entire build team, and probablly the Mythtern as well. By establishing exactly what would be necessary at the beginning, it would have made it easier to succeed. Off the top of my head, I think it could have been approached like this: What you want is the greatest purchase in a material such as concrete. You want a deep hole while still using a man-portable device. Therefore, the projectile should be as thin as possible, as dense as possible, and travel as fast as possible. You want the impact end to be designed to penetrate efficiently (check out various projectiles, drill bits, nails, etc, experiment with accute or obtuse angles and various hardened materials), some sort of wedging device after the impact head so that the projectile locks into the hole it has created, and possibly some way to augment the weight, like a lead core or using tungsten. You could base a projectile firing device around a firearm, or go with fast release nitrogen and borrow some of Grant's stuff. You could even go super pressure by using dry ice as your pressure source and creating a super reinforced pressure vessel. I wouldn't mind seeing this one revisited.

-ATX Maker

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Originally posted by apocalypton:
1. It is a GREAT pleasure to report - with the help of highly skilled engineers from diverse industries - that all basic components of a workable miniature Batman winch have been identified.

2. The newly specified components will work in engineering and building the winch, as well as be a bit smaller in diameter, and also only half as long as the MythBusters right-angle gearmotor unit. That said, we are deeply appreciative of MythBusters' work on this breakthrough, after two years of our own engineering efforts that could not outdo the PowerQuick. The MB achievement - over a matter of only weeks - did what not even a DARPA contract to the aerospace industry was able to accomplish in years!

3. Our engineered winch:
- 0.6 motor horsepower, equal to that of MythBusters.
- Greater output torque, enabling lifting and lowering 350 lbs.
- Full electronic braking.
- Both forward and reverse operation.
- One right-angle, geared speed reducer, replacing three of MB's reducers and gearing.
- Half the weight of the MB gearmotor unit.
- 12 Volts DC, rather than MB's 44 VDC.
- Larger and single, rechargeable battery unit for longer operation.
- Miniature motor controller, plus servo adjuster, a fraction of MB's size.

Keep up the good work, MB - sometimes proving the pros wrong, and inspiring us all.

~Z

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winch