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Ring Launcher Test Results

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LAN_403

FastMHz

Thu Mar 09 2006, 07:05PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

"Good luck and if you find a good material to use then let me know."

I've been searching, and noticed that a Planters medium sized peanut can is the perfect diameter, strong and light weight. I trimmed all excess metal I could and siliconed the aluminum disc to the bottom, placed it upon the launch pad out back, and prepared to launch. I had an audience of family members. We expected it to go a few feet into the air...well, I pushed the "detonator" and it disappeared with a noise of gunfire!! It went way up, I have no idea how high but it took a bit to fall. Now that I know what to expect, I'm reinforcing it and will take video and time measurements. Stay tuned!

"Have you tried shooting _not_ at the chrono and checking if it displays something, due to EM interference?"

Yup, it just keeps rolling the ready symbol on the screen. It's a metal unit, I think this helps prevent EM interference.

"Paralleling your SCRs is probably useless"

I have a seperate resistor in front of each gate to prevent this...saw this posted somewhere in the old forum.

"What kind of backstop do you use?"

A pile of sheets and cardboard boxes

Maz

Fri Mar 10 2006, 03:23AM

Registered Member #111 Joined: Fri Feb 10 2006, 01:04AM
Location: Menasha,Wisconsin
Posts: 65

around where i come from paper is a big industry. i used to work for a box making plant and they had a thin sheet plastic that was durable, light and easily worked with. they called them die boards. they use them to cut patterns for boxes by gluing knives to one side. that would work. good luck finding a ox manufacturer around you!

Quantum Singularity

Fri Mar 10 2006, 06:04AM

Registered Member #158 Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282

Is there a proper name for this type of ring/disk launcher? When I get to working on my new improved one I will be documenting it on my website and was wondering if there is a more appropriate name. I have tried researching and a Thompsons Gun typicaly utilitizes a selenoid style coil and a ring, along with a center section of ferromagnetic material. An Induction Coilgun also uses selenoid field coils but uses a slug that passes through inside the coils. What I am building - and I think FastMHz - utilizes a flat 'Archimedes' sprial field coil and a similarly shaped flat disk, which is just single stage. Did I miss the common name in my research or is there none?

Dr. Shark

Fri Mar 10 2006, 08:45AM

Registered Member #75 Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711

I don't know whether you guys are aware of the work of Thomas Rapp here

. He uses the aluminum disk as a sabot to launch a ball bearing ball as the main projectile. Of course you loose about 50% efficiency this way, but I think this is affordable with a ring launcher. This allows you to use any type of projectile you like!

I have also seen some IEEE Magnetics paper on this kind of launcher, they used two coils at 90 degrees with the projectile in between, and got some unbelivable efficiency like 30%.

FastMHz

Fri Mar 10 2006, 06:32PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

That's some neat stuff on the German page...I'm also interested in knowing more about the 90 degree double coil launcher...

I think the proper name for these things is "Mass Driver"...at least, that's what Nasa calls them IIRC.

I think I'm going to try and form a rocket out of "great stuff"...could be messy, but it might just work. The Peanut can I mentioned earlier "accordioned" after one launch.

Quantum Singularity

Fri Mar 10 2006, 07:01PM

Registered Member #158 Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282

Yeah, I have looked over that German page a few times but since I cant read German I just look at the pretty pictures

I have seen the "mass driver" name too, but c'mon, thats not as catchy as Gauss Cannon or something like that

90 degree double coil launcher? Are you refering to the 'Lateral Disk Launcher' illustrated here

also known as the 'Reconnection Coilgun'. I am curious to try this design but I am not certain how it could be nearly as efficient. Placing a disk on a flat spiral will yield high coupling and large induced currents, wich repel the disk strait away. Trying to sandwich a disk between two coils and launch it sideways wouldnt seem to be as efficient. And with the really high power levels I would be scared of the possibility the disk might shoot out at different angles. Would have to build a serious safety chamber around the thing. I have already shown my earlier design could penetrate into a good thickness of wood with a 5" hard drive disk. If I used a 3.5" or smaller disk (which I will probably do) with over twice my original energy...

FastMHz

Fri Mar 10 2006, 11:02PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

Finally - video of the ringrocket launching!! This one was a metal coffee can with the 5/16" aluminum ring screwed into the bottom. After launch, the can was about 1/3rd less in height as it accordioned, meaning that a ton of energy was wasted in smashing the can instead of altitude:

DVD Quality Footage

Quantum Singularity

Sat Mar 11 2006, 01:39AM

Registered Member #158 Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282

Pretty cool! Keep the camera rolling in your future runs! How did you form the cone - looks homemade? I take it the rocket didnt come down in view of the camera... or else it must have went really high...

About the pvc suggestion... I havent really worked with the stuff much, but they sell thinner pvc for like sewer drainage or something like that, would be thinner and lighter than say the common sched 40/80 stuff. Or take a plastic jar / container and coat em with several coats of polyurethane or epoxy to give em extra strength? Probably too much hassle, just thinking of ideas thats all.

FastMHz

Sat Mar 11 2006, 06:37PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

In the video, the cone was formed from sheets of paper. I then mixed wood glue with water and painted it with that to harden it. I figured they better be easy to make and cheap since they get destroyed after each launch.

The rocket came down to the left of the field of view after landing on the roof and bouncing off. That's why you hear two crashes after launch. I'll get a cameraman to follow the rocket in some future footage. I still need to design a strong, yet light weight rocket that won't compress during launch.

I'll dig through the PVC at the home center and see what I can find...The Gs being experienced by the rocket must be sky high...pun intended

FastMHz

Fri Mar 17 2006, 08:35PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

Two things:

I just finished making a new rocket out of Great Stuff...it's surprisingly solid, weighs less than the cans, and shouldn't crush...I hope...

I also won another 1.7kj cap bank on ebay...so I'll start planning a 3.4kj launcher

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