As surprising as it is, there really is no where on the internet where I found any decent instructions on how to make a grappling hook gun. Figuring it would not be that hard to make, I decided to design and make one myself. After running into many problems, obstacles, and a few prototypes, I think I finally have a really solid version that definitely will impress all who use/see/build it. Naturally there are sure to be plenty of upgrades and other ways to accomplish what I did but I will share the parts and methods I used to make this particular launcher.
Although I call it a grappling hook launcher, it is basically a souped up version of any pneumatic gun. I took the best aspects of many different spud guns to make one of the best possible systems doing my best to avert creating any weak spots and not using any dangerous PVC (which shatters when over pressured and does not work well in the cold). This system is designed to be robust and efficient in every aspect of its construction. It is not hard to build and the most trouble anyone would have is gathering all the materials needed.
I tried my best to used parts locally avaliable (Home Depot, Lowes, etc) but a few i needed to order online. Feel free to ask me any questions you may have.
For everyones information, if you are really that concerned about why I didn't film myself climbing the rope, you are missing the purpose of the video, to show you how it works. The hook and rope combined for my gun weight 2lbs 2.1oz for anyone concerned that this device isnt practical. Also, I launched the hook at 150 psi and you could go much higher to achieve greater heights.
A little background on myself; I am current a Mechanical Engineering Student at the Massachusetts Institute of Technology (MIT) and have been building things for 14 years. My personal blog has most of my creations (some of them made by following Instructables). Enjoy.