R/C Naval Combat

Some of you may have seen the beginning of a hybrid cannon experiment that will occupy at least one of turrets of my tirpitz. The goal is something that is easy to have rotation and elevation control on, and is combat effective in fast gun. What I have is effectively a hybrid big gun cannon with a good deal of internal volume removed in an attempt to increase the max rate of fire. So far, it has passed the manual feed tests but I may need lighter springs on the interrupters. The feed from a full magazine was very good when manually activated, which calms my main worries.

This is a twin mount properly set up for the tirpitz. I have one more part to make once I make sure that it functions properly. It will feed BB's and 3/16" ball bearings. Now if it works out, it should be possible to use an aluminum tube with some tapped holes in it and two end caps with a molded insert with the complex geometry to make a functioning version... we'll see..

anyways, picture time!

Can you show us the internal mechanism? A diagram of how it works would be great. I'm very interested in how this project turns out.

Sooo pretty... Is the block on the bottom where the interrupters go?

yep. internal pictures coming after testing

Well, time to post some pre-testing pictures from my cannons. They will feed 3/16" bearings and bb's (so far, we'll see with real gas flow). They've been designed to hopefully allow fast gun firing speeds. There is a mount on the top between the fill ports that will fit a sideways HS81-85 servo to do elevation control. After I make a ring that will bolt to the top and sit in a ring bonded into my tirpitz, it will allow rotation as well (I hope) but first off, it has to pass testing. So far it has passed manual feed tests, now it is time to test with full pressure co2 and o-ring breech.

It is a bit overly complex on the top right now but the basic cannon if it works would be easily changed into a molded insert for a tube of appropriate size with bolt on caps... which might make it a feasible design to make.

http://thetriphome.blogspot.com/2007/05/ready-for-testing.html

I wonder how it would do with a "geek" breech?

Pretty wanking cool greg.

Was that all done with a milling machine?

nope. It required both a lathe and mill

It WORKS! now only three more to make and the ole tirpitz will be quite the threat! a bit more tweaking of spring choice is all she needs

Well, yet more enhancements (and some swearing at aluminum, I broke off a drill bit while making a second cannon, which unfortunately means that I have to start over again on the second one... And I determined that due to the good seal between the two sides of the piston, I had to set in a piston stop in addition to the spring. The piston over compressed the spring (and these are not weak springs) and was jamming one of the pistons. (and this is at 110 psi not the standard 140 or so)

Anyways, more cannons to make.

-Greg

How are you working in the piston stop? a screw coming in from the side, or like a sleeve inside the spring?

A sleeve on the outside of the spring. It makes it more reliable, easier to make, and dramatically increases the spring choices available. Coincidentally, the pistons that I am using, are mcmaster.com 3/16 X 5/8 pistons ground a bit shorter made out of 18-8 stainless. They have a wide head which is perfect since the case diameter for .223 Remington perfectly fits over the outside of the spring and piston, so I cut sections of the case off to make the sleeves. (as a bonus, I can get this all day long from the local range for free).

Archer,

Did you post this on cnczone's forums? There was a thread there with the files what looks like these exact parts that I commented on.

Regards,

iamscottym

Yes I did... I posted a RFQ to see about having some sets made for some folks... Still got to get mine working properly first.

What mill are you using? I'm planning on getting a grizzly X3. I'd prefer a bigger mill, and wouldn't mind forking out the cash for a bridgeport, but I'm in college and just don't have the space. I'm just hoping an X3 will cut half way decent, as I'm used to bridgeports on up to 5 axis VMC's.

I have a taig. definitely the best bang for the buck (especially if you put your own steppers on it rather than buying the kit) in the table top mill arena.

I like the taig, I'm sure it requires less tweaking to get working properly than an X3, but it's probably a bit small for me. I do really like the high spindle speeds, but my biggest concern is the small motor. I'd imagine making that gun took quite a while.

What CAD/CAM software are you using? Right now I have alibre xpress and Pro/E (student), and am debating what to go with next. I'll probably get solidworks (student) because it comes with Floworks on top of all the other FEA add ons, but I need to decide on a CAM package to go with it. Alibre Pro (student) comes with VisualMill and one other, which I'm also considering..but it can't compare with solidworks in terms of analysis packages.

WHOA... so you don't have a mill; you have a cnc?

Yes, indeed he does. How else would he make the contours inside his gun?