R/C Naval Combat

Posted By djranier on 22 Jun 2010 04:31 PM
What rule set are you building to? The MWC does not allow the barbetts to be cut down to allow the guns to sit lower, not sure about the other clubs, IRC, and treaty. Of course the forward level of yours may be the top of the barbett, and the turret may cover the excess barbett around the sides and back. Just thought I would mention the rule just in case you did not know about it.

I am building to Treaty rules which does have the no barbette modification rule.  The cutout is level with the bottom of the turret, while the raised part will be where the turret connects. Actually, the cutout really doesn't let me change the down angle of the guns - I can point them down far enough to shoot off the fantail right now.  What I really need to do is increase the height of the barbette, but I don't think the rule allows that either.  I should still have a little clearance beneath the turret on the  inside, so I'll start by raising the gun a little farther in the turret and see what I get.  But that will have to wait until I get a turret made.
 

Posted By Tugboat on 22 Jun 2010 05:34 PM
Dave has a point. Also, having the raised part around the knurled fittings will make tweaking the guns less comfortable!

Yep, it's a little tight around the barrel nuts.  I can turn them, but raising the guns a little and relieving the the barbette a little should make it a little easier to adjust them.

 

Posted By Tugboat on 22 Jun 2010 07:09 AM
Nice gun mounts... I guess you can use shims to change the angle they're shooting at, too.

Definately jealous of your CNC mill (and skills with it as well!)

To change the angle of the guns I just need to adjust the nylon screw in the back of the mounting plate.  After loosening the two hold down screws, I turn the elevation screw in to lower the guns and turn the screw out to raise them. The straight part at the front of the mounting plate acts just like gun trunions, forming the center of rotation.  Backing the screw all the way out means the gun plate rests flat on the mounting plate inside the barbette, ensure that the guns cannot be raised above horizontal.  When I got it where I want it, I just tighten down the hold down screws.  My current disadvantage is that I have less than 5 degrees depression to work with before I start hitting my own deck.

The CNC has been a lot of fun, even after having it several years I still love to to just sit and watch it cut out parts.

 

I finished making two molds for the turrets.  While I thought I had plenty of draft built into the plug, when I tried to take them out I couldn't budge them.  So I had to use a chisel to remove the plug from the mold.  The molds still came out pretty good, far from perfect, but very useable.  I have made 5 turrets so far, and the 6th and 7th are curing right now.  Here's the first one that came out of the mold.

Molding in the line to define the barrel openings worked out very well - it made it very easy to cut out the slots.  Here's there rear three turrets with the guns mounted.  It's really starting to look like a ship now.

Posted By Greg McFadden on 27 Jun 2010 01:53 AM
looking very nice. your taig can quite easily mill those molds directly for you, if you are so inclined to code it (I particularly like machinists wax for molds, if it doesn't turn out well, melt it down and try again).

I had not thought about milling the molds directly, but I have thought about trying the machinable wax.  The wax always seemed expensive to me, but I guess if you can melt it down and reuse it, it might not be so bad.

 

Posted By Tugboat on 27 Jun 2010 08:18 AM
If you're going to mill plugs and then make molds, I highly recommend Smooth-On's Mold-Max material... takes overnight to fully set, but it's firm, yet has enough give to pop the pieces out by hand.

I'll have to look into that material.  I was also talking to Buddy about alumilite, which uses a flexible mold material that I would like to try.  However for the turrets this time, I though I would stick which what I knew.

 

Thanks Greg - I didn't know they made tapered end mills.  That makes creating a mold on a 3 axis machine possible.  I checked out the mills and I'll put them on my wish list. Unfortunately, the tooling list is always much bigger than the budget.

I finally finished the water channeling in the Roanoke.  I started with a can of door foam, expecting to use it as the final water channeling.  Having used cans of foam for various house projects, I know it is not easy to apply evenly.  So I experimented with the foam a little and thought I had the problem under control.  However, it didn't work out near as well in the ship as it did in my experimental tries, so it looked pretty bad and also had a lot of holes.  So I sanded the foam down and bought a tube of Quikrete self-leveling polyurethane concrete sealant. I put the sealant over the top of the foam, applying it in five separate sessions - left side, right side, back left, back right, and back center.  I was very pleased with both how easy it was to use the sealant and the nice appearance of the finished work.  Overall I used about 2/3 of a 10oz tube, so it did not add excess weight either.

Finished water channels

Indeed. Nicest cruiser build I've seen in a while, the fact that it's your first combat model makes it even more impressive.

I would like to be able to make my own regulator, given the expense and weight of the commercial models.  However, I have worked with high pressure systems in my professional life and I have a healthy respect for them.  Requiring commercial tanks and regulators is a very wise rule in this hobby.  The rest of the stuff is fair game however.  I have a pump design on paper as well as a gun modification drawn up, I'll work on them for my second model.  And of course the stuff from Clippard is so nice I wouldn't waste my time making any of that.

I've mocked up my CO2 system.  I was hoping for a test fire today, but the day was consumed with honey-do lists . I made a manifold to attach my two MAV2s to, and it also acts as a T to bring in the 1/8 supply line and put out the pilot valve supply through a 1/16 line.  The valves will be actuated by MPA-3s, which in turn are driven by 10mm pilot valves.  I'll use a radio switch to operate the 10mm valves, both together for now, but with the option to operate them separately if I move a gun to the front.