High Speed Electric - Battery Winch
Published : 29th October 2004
I'm working on an ultra light cable cam rig for a job shooting in a few months. The rig must be carried deep into rough terrain by no more than two Techs. I'm looking for a HIGH SPEED ELECTRIC WINCH WITH BATTERY system to haul lines up to 3/16 thick, that will run off d/c power.
If anyone has extensive knowledge of such systems, I could use a little help.
I've seen the fly cam, Spydercam and superfly, but this will exceed even the capabilities of these rigs.
Here's the specs I have been ordered to adhere to :
- No tools required for set up
- Weather resistant, operating temperatures from -40C to +35 C
- Air shippable with standard baggage
- 2man set-up, 3 hour rig time
- 900 ft spans with a y-axis variation max of 66 feet(20m)
- 20kilo/45lb camera payload max wt
- 360 pan, 140 tilt, 0 roll
- Operational run time- 4x 400ft Arri loads, 12 full length passes at max speed, plus reserve for emergency retrieval
- Line/carriage speed of 60mph, sustainable for 1 minute
- Dual redundant speed controller with optical stepper/servo
- Remote operation of iris, focus, cam run/stop, dolly l/r, video feed
- Programmable repeatable moves, single sequence only
- Solar recharge only
I'm employing a carbon head, chassis, d-12 spectron lines and lewmar fittings to save weight, but the battery and drive unit weight is killing me.
If anyone has some suggestions.... (Lith-ions? Halyard Drives? Hydrostatic?)...please help a brother out.
Key grip, Toronto
Patrick Thompson writes :
>I'm working on an ultra light cable cam rig for a job shooting in a few >months. The rig must be carried deep into rough terrain by no more >than two Techs.
Talk about being in deep....
>If anyone has extensive knowledge of such systems, I could use a little >help.
I have spent quite a bit of time researching winches for a couple of projects. Here what I've found.
There are light weight winches and there are high speed winches. These two characteristics are not found together in any commercially available system. I was told the Navy had something like this for towing sonar equipment behind submarines. Apparently it's very fast, but very large. Likewise for aircraft. These were ll hydraulic. Also, there are lots of DC winches : 12volt, 24 volt and 120 volt. The problem here is that generally the lower the voltage, the heavier the system -- for the same mount of work.
A couple of ideas: power the winch or the traveller with a small gasoline engine as in an ultra lite aircraft, or else pull the camera back and forth with manpower, or a man powered multiple pulley system.
A couple of thoughts : will you be able to tension the Spectron sufficiently to limit the cantenary curve of 900' with 45lbs. on it. Whatever system you devise, it's going to have to work very hard going up a 450' hill. I don't know of a battery that two people can carry that can be reasonably solar recharged and put out the amount of energy that it seems will be required.
Is an air drop out of the question?
IA 600 DP
>Is an air drop out of the question?
To Brian, the solution to most problems involves a helicopter.
Jeff "grounded" Kreines
The spectron can handle the load. I've tested it for tension, abrasion, dynamic stretch and more, and have found that it far outperforms all cable to date. In the event of a pulley failure, the rig can be DRAGGED on the line to a recovery point because of the smooth Teflon like finish. The full name for the line is "Marlow/Samson excel spectron d-12" and it costs around $2.10USD per linear foot.
It weighs about 1/10 of a comparable diameter, 9/19 stainless aircraft braid. When you get into 4000 feet of the stuff, it equates to a massive weight savings. Also, it does not require swaging or large HSTO's when rigging. With a simple knitting tool, a friction knot can be wrapped around a stainless thimble for a very clean, 100% strength tie off.
It comes in various bold or neutral colours as well, which facilitates line assignments for rigging/de-rigging or entanglement situations.
Enough about me and my big long rope. Lets talk winches...
The winch system will be a one off, probably alum & carbon fibre. I've got a few guys in town bidding on primary components right now. The d/c motors are becoming a problem though. The closest I could find to a match was a high end Bosch starter motor for a Carrerra. It is not that directional though, and I cannot afford a failure.
I've dropped a line to a few supergeeks...I mean UUBER geeks at battlebots.com (don't ask). They're looking into high speed servo motors for Bomb squad ROV's, and Stepper motors from aircraft wheels....apparently some advanced planes have "pre-touchdown wheel accelerators" that prevent blow-outs on hot runways....who knew? The motors will have to be in the 2-3SHP range, d/c and reversible, preferably planetary geared with optical encoders.
If anyone knows of a rigger that has had to fly some crazy rig a hundred miles an hour, drop me his number. I've got a monkey on my back, and he's holding a production schedule.
The batteries can have a combined total weight of 150 lbs, must have sufficient crank amps, and must be sealed to meet eco guidelines regarding spillage.
Key Grip, Monkey Boy, Geek Magnet.
Patrick Thompson wrote :
>Enough about me and my big long rope. Lets talk winches...
>The winch system will be a one off, probably alum & carbon fibre. I've >got a few guys in town bidding on primary components right now.
The darn rally car thing looks like a snap compared to this. I'd like to see pictures of both solutions... if there are solutions
Patrick, I'm not questioning your choice of Spectron over anything else. Samson makes a great product. Just be sure one of your uber geeks runs the numbers on the amount of strain on the rope necessary to pull your estimated load up a 450' hill at 60mph.
>The batteries can have a combined total weight of 150 lbs, must have >sufficient crank amps, and must be sealed to meet eco guidelines >regarding spillage.
Well in that case, talk to Stuart Cody at Automated Media Systems : 617-787-4313. He's your man for light weight batteries.
Good hunting for the motor. The high performance ones you mentioned, especially the aircraft ones, are meant to be (over) run for very brief periods before they overheat.
IA 600 DP