Aircraft carrier cable

bspooh · Dec 9, 2004

I am running into a brick wall here..I'm trying to find some information on the cable that stops the planes on an aircraft carrier...I need to know the shear strength of that cable..

Anyone know of a website or something that might have the answer??

Thanks,
Brent

andy pullen · Dec 9, 2004

Did you try writing to Newport News Shipbuilding? (Now Northrup Grumman) I wouldn't think that information would be classified.

Andy Pullen

scooter · Dec 9, 2004

Go to the source man. Look up the web site for a particular carrier and email someone in the ships company that works with the arresting gear equipment. I can guarantee it's probably twice the shear strength of the bolts holding the tailhook on(and that would be for their heaviest aircraft) and those bolts probably have enough strength to allow for twice the weight of the aircraft.

The cable itself is strand - don't know how many. Also, it's the arresting gear engines that take all the force, not the cables. The engines are calibrated for the particular aircraft being arrested - just as the catapults are adjusted for the type of aircraft being launched. Acceleration(in this case neg. acceleration) is a tricky science.

In other words, if your hoping to find some incredible strength factor, you'll probably be a little disappointed.

Good luck

bbfmetalworking · Dec 9, 2004

Brent,
Look up the characteristics of 1-3/8" stranded steel cable and you'll be in the ballpark.

Here's a process description from
http://www.globalsecurity.org/military/systems/ship/cv-design.htm

"Four 1.375-inch-thick steel cables run 2-5 inches above the deck at 35-40 foot intervals and connect with a hydraulic cylinder below the deck, which services as a giant shock absorber. As an aircraft approaches, all four wires are set to accommodate that aircraft's weight. When the aircraft's arresting hook snags a wire, the wire pulls a piston within a fluid-filled chamber. As the piston is drawn down the cylinder, hydraulic fluid is forced through the small holes in the cylinder end, thus absorbing the energy of the aircraft and braking it to a stop. An arresting wire can stop a 54,000-pound aircraft traveling at a speed of 130-150 miles per hour in a distance less than 350 feet. When the aircraft drops the wire, the piston is retracted and made ready to recover another aircraft in 45 seconds."

scooter · Dec 9, 2004

oh yeah - forgot to mention.
THOSE ARRESTING GEAR ENGINES ARE FREAK'IN LOUD!

jburstein · Dec 9, 2004

well, using some basic physics, and numbers available online, I calculated the force it takes to stop one of those jets.

I assumed:
constant deceleration (probably not valid, but good for an approximation)
Mass of jet = 66000 lb
speed = 150 mph
distance to stop = 320 ft.

using that I got 155,000 lb as the force. Of course that is not equal to the tension in the cable--the tension will be significantly higher than that. Probably significantly above 1,000,000 lb.

Out of curiousity why do you want shear strength? That cable is used mainly in tension, isn't it?

-Justin

[edited to fix the I-just-woke-up grammar]

bspooh · Dec 9, 2004

Too make a long story short, I need to be able to cut this stuff in half...An abrasive saw is out of the question, it has to be a hydraulic cutter..

I need to develop a cutter for this..I just don't want to "trial-and-error" it..I have a piece of this cable on my desk, and it is the toughest thing I have ever tried to cut...

thanks,
brent

jburstein · Dec 9, 2004

Ah. Yes. That's a rather different problem; I don't know nuthin' about that one.

jwaggs · Dec 9, 2004

One other factor to bear in mind, when the aircraft catches the cable the pilot goes to full throttle. This is in case the cable breaks. So you would have to factor in the thrust of the jets engines at full throttle

metlmunchr · Dec 9, 2004

I'd imagine most any of the major wire rope manufacturers can give you the info you need, since most of them would be regularly bidding to supply this rope to the government. On the other hand, the strand hardness should give you a good indication of shear strength.

jkilroy · Dec 9, 2004

That is going to be a tough order to fill. I used to use a lot of stuff from Enerpac when working on cranes, you might check them out. What is the strand configuration?

You can cut it on a cold saw however you are going to need to fabricate a round clamp for use on both sides of the cut.

JRIowa · Dec 9, 2004

I don't know if it's still out there, but Whitney used to make a hydraulic cable cutter. Everybody called them "fire Plugs".
JR

Ries · Dec 9, 2004

Enerpac definitely makes a range of hydraulic cable cutters. And if they dont have one that will do what you want, they might be willing to engineer special blades for you- I doubt the tonnage of the cylinders is going to be the problem.
The other thing you might consider is cutting this stuff electrically. I recently worked on a project where my wife had some stainless steel yarn made up by a factory in Belgium- 100% Stainless steel, but instead of just a few strands like in a wire rope, this had close to 2000 strands in a 1/4" diameter, so it tended to fray. I found a guy in Connecticut who makes hi-frequency electronic cutting machines for wires and cables. His machines actually hold the cable rigid, and run very hi-freq hi-voltage electricity through about 1/16" of length where you want it cut. Not only does it cut the stuff, but it fuses both ends so they wont unravel at the same time.

here is his website-
http://www.ewaldinstruments.com/

The guy who owns the company is a real nice guy, and he will be able to tell you if his machines will do what you want or not- he will even cut a sample for you and send it back to you, if he can. This machine is incredibly slick, and much nicer than a giant hydraulic shear. I ended up just renting one from him for 6 months, at half the price of a new one. There was no other technique that could do what I needed done.

jim rozen · Dec 9, 2004

How about a flame saw?

Jim

scooter · Dec 9, 2004

OK - Here you go. Depends on the Mod.

MOD 2 - 195,000 lbs - Diameter 1 7/16"
MOD 3 - 215,000 lbs - Diameter 1 7/16"
MOD 4 - 215,000 lbs - Diameter 1 7/16"

This is what the Navy calls "Purchase cable break strength". This is the unclass stuff.
hope this helps.

[ 12-09-2004, 01:22 PM: Message edited by: scooter ]

scooter · Dec 9, 2004

I hope I didn't mislead with my last post.
The arresting cable and "deck Pendant" are two different animals. The cable is was is run out to arrest the aircraft - the pendant is the actual cable the tailhook engages that lays across the deck. It's the easily replacable part of the system (for obvious reasons).

Deck Pendant:

MOD 2 - 188,000 lbs - 1 3/8" diameter
MOD 3 - 205,000 lbs - 1 7/16" diameter
MOD 4 - 205,000 lbs - 1 7/16" diameter

This is the deck pendant breaking strength

I think these cables are manufactured by:
Paulsen Wire Rope Corp.
880 South 2nd Street
Sunbury, PA 17801

scooter · Dec 9, 2004

Paulsen bought out of bankruptcy - now Wirerope Works

http://www.wwwrope.com/products.htm

jfsmith · Dec 9, 2004

This a an area where I have seen the planes land, and the arresting cable at work. But these cables have a life span gauged by the number of landing and aircraft types. So The strength of the cable is changed with it's usage. So I am not sure what to say about the quality of the cable.
But any place that can cut truck leaf spring can cut this sort of cable. I get some of my steel from these places and they have a monster machine for shearing the springs.

Jerry

mark ct · Dec 9, 2004

whats the reason for cutting it, i dont see why abrasives wouldnt work if ya held the cable rigid on both sides, but myself i would like to cut it with a torch since then there are no sharp wires it fuses them all together, can ya tell us more about why your cutting it, to scrap it? installing new stuff?

scooter · Dec 9, 2004

Heat (abrasive or the torch) will dramaticaaly change the properties of the cable. This is no problem if its to be used for something other than holding a load - something like....yard ornaments.

Aircraft carrier cable

Cast Iron

Hot Rolled

Plastic

Aluminum

Plastic

Hot Rolled

Cast Iron

Hot Rolled

Aluminum

Diamond

Diamond

Diamond

Diamond

Diamond

Plastic

Plastic

Plastic

jfsmith

Guest

Hot Rolled

Plastic

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