Timescapes - Digital Timelapse Discussion

Grappeling Gun
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Author:  sciencelookers [ Thu Dec 31, 2015 10:09 am ]
Post subject:  Grappeling Gun

For the past two years my nephew has asked for a grappeling gun. Since nobody was waiting for a focus motor right now, I decided to go to the shop and make him one. A regular pneumatic potato gun throws the hook and a battery powered drill reels you up. Of course you have to prototype something at least three times before you know what you're doing. In this case the first prototype can be given to the kids instead of the recycle bin.


For the second prototype I think I'll use a small pneumatic spear-gun pistol to launch the hook and I'll pay for a stronger electric drill. The motor/gearbox from the drill gets removed and put in a custom housing which is smaller and attaches to the spear-gun.

Author:  Kitwn [ Mon Jan 04, 2016 9:32 pm ]
Post subject:  Re: Grappeling Gun

OK, I'll take the hook: Why does he want a grappeling gun?

Author:  chardie [ Tue Jan 05, 2016 1:37 am ]
Post subject:  Re: Grappeling Gun

Kitwn wrote:
OK, I'll take the hook: Why does he want a grappeling gun?

Dunna nuna nuna nuna nuna nuna nuna nuna BATMAN !! :lol:

Author:  sciencelookers [ Tue Jan 05, 2016 6:14 am ]
Post subject:  Re: Grappeling Gun

Kit, Chardie guessed the answer to your question. He wanted one because Batman had one and it was cool.

Author:  Kitwn [ Tue Jan 05, 2016 7:47 pm ]
Post subject:  Re: Grappeling Gun

Sounds reasonable to me.

Author:  chardie [ Sat Feb 06, 2016 4:21 am ]
Post subject:  Re: Grappeling Gun

what sort of range does it have ? might be of some use retrieving drones from trees :roll:

Author:  Kitwn [ Sun Feb 07, 2016 4:23 am ]
Post subject:  Re: Grappeling Gun

Better still, you could fit it with a net and use it to catch drones trespassing over your garden.

Author:  sciencelookers [ Thu Aug 25, 2016 11:23 am ]
Post subject:  Re: Grappeling Gun

The pneumatic gun could throw that hook at least 20 feet straight up with 40 pounds of pressure. That should be well within the safe limits for the PVC pipe. It could shoot farther if I was brave enough to put more pressure in it. There is a golf ball cannon which is similar. It can launch a golf ball about 300 feet at 40 pounds pressure. I made another golf ball cannon that used a self igniting propane torch as a fuel/air source. it shot golf balls much farther and was portable, but I had to take it away from them after seeing one blow up in a guy's hands on youtube.

The pneumatic speargun did not have enough force to throw that heavy hook. For the next prototype, I got a gun called a dummy launcher. It is used to train hunting dogs. You put a blank 22 caliber shell in the gun, and a large, soft "dummy" goes over the outside of the barrel. There is a short bit of steel pipe inside the dummy with the end welded shut and an O-ring gasket that seals to the outside of the gun barrel. You point it away from you and your dog and shoot. The dummy flies about 100 yards. The gun kicks like a 12 gauge and makes a loud noise. You are supposed to use this to get the dog used to loud bangs, and train him to go get whatever falls from the sky.

I cut apart one of the dummies which is how I found out it had the steel tube inside. The plan is to weld little arms on it like the other grappling hook had. Assuming it doesn't blow up the first time I shoot it, I plan to make a separate "ascender" device to haul me up the rope. It will have a drill at each end with one cross-wired so it turns backwards relative to the other. This follows a theme I am seeing in several recent builds where I use two motors to add more mojo to my moco. I'd like it to pull the rope through instead of just winding it onto a spool. This would let me shoot a long rope and clip the ascender onto the rope anywhere instead of always having to wind it up from the end. It also gives more torque because torque drops off as multiple turns of rope make the pulley larger in diameter.

I'm wondering if a gopro would survive being shot by the dummy launcher if it was embedded in a soft foam rubber dummy. Little fins on the dummy might let it fly fairly straight without rolling excessively. I've seen video from cameras catapulted before but they were all disappointing because of excessive tumbling once airborne. Something like that, but stabilized ought to be pretty exciting.

Author:  Kitwn [ Thu Aug 25, 2016 5:08 pm ]
Post subject:  Re: Grappeling Gun

Americans and their guns! ;)

One option re the Go-Pro might be to launch it and let it come down on a parachute, maybe a paragliding shaped one with a fin to stabilise the direction the camera points.
The military have a folding surveillance aeroplane that is launched over enemy territory inside an artillery shell. Apparently those machines manage to survive about 600G acceleration, so the great Sciencelookers should be able to make one that can be popped out of a drain-pipe :D


PS Can you tell I have my facetious head on this morning?

Author:  sciencelookers [ Fri Aug 26, 2016 6:14 pm ]
Post subject:  Re: Grappeling Gun

I'm sure it would survive being fired from the pneumatic gun. Its a good idea actually. Maybe I can make something that goes over the outside of the barrel like the dummy launcher for training hunting dogs. That way it could have fins at the back to stabilize its flight. Stabilizing fins would be more difficult if the whole projectile had to fit inside the barrel. I suppose there could be spring loaded fins that pop out as soon as it leaves the barrel, but the simpler solution sounds easier.

What I was concerned about was the explosive acceleration if I shot it from the dummy launcher itself. Your comment about the spy artillery shell is encouraging. If the army can fire the equivalent of a gopro out of a cannon, the little 22 caliber dummy launcher should be no problem. The dog training dummies go a really long way. It would be an exciting video if the camera survived.

Your comment about a glider sounds fun too. I wonder if a radio control receiver would also survive the launch. A second person could attempt to pilot the projectile.

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