Cannon Systems – Big Gun
Strike Models is now selling John C White’s Weapons Manual #1 and his plans for a Rotating Gun System.
| Publication | Description | Sheets | Price | Part # | Buy |
|---|---|---|---|---|---|
| JC White's Rotating Gun System | These are full scale drawings and instructions for making rotating cannons for 1/4", 7/32", 3/16", and 0.177". | 4 | $30 | JC-RGS |  |
| Weapons Manual #1 | JC White's instruction booklet for making reloading torpedo guns and bending barrels. | Booklet | $30 | JC-WM1 | |
The first set of Big Gun Cannons are finally available.
A Strike Models triple 3/16" turret.
After Strike Models acquired the BDE R/C gun systems, we had to make some major changes to the design in order to bring down the part cost and make them manufacturable with the equipment we have. One of the reasons that BDE had stopped making the cannons was that the part costs had increased drastically (in some cases tripled).
We will be selling about 15 sets of triple 3/16 or BB turrets. The price for each turret is $206 each. These are hybrids between a BDE R/C magazine section and a Strike Models redesigned accumulator. More sizes will be coming, but this will allow us to get a number of units and get feedback on how well they work. We did not get enough parts of the larger sized cannons to go forward with that release right now. We understand that the triple 3/16 cannon was not the most eagerly awaited version, but we had parts to do it.
These cannons are designed to be o-ring belt driven as opposed to the gear or chain versions from BDE R/C. The end opposite the accumulator is designed to fit a standard sized servo to drive the rotation. This servo can be a normal servo (with fairly limited rotation, a hacked servo, or one of our standard sized sail winch servos. A Buna-N o-ring with a 1/8″ thickness is good for the rotation belt. A bracket can be attached to the side of the turret to mount the servo (designed, but not yet made).
The bottom of the turret has two hole to help place the turret. The side of the turret base has 3 through holes allowing a 6-32 rod to go through or else tappable to 8-32. These hole will also be used for the bracket to hold the drive servo.
Test with the turret blow through 2 inches of polystyrene foam at less than 125 psi. The gun works well with a single pressure source. The accumulator volume is 4 cubic inches, but other sizes are available.
Here are some basic stats for the initial batch of turrets:
- 2.5″ magazine good for either BBs or 3/16″ ammo (single layer).
- 5.82″ overall length of unit (excluding servo and accumulator air feed barb) with an accumulator of 4 cubic inches.
- Base to top of plastic magazine is 2.75″
- Maximum width of base: 2.1″
- Closest turrets can be butted together without servo between them: 3.25″
- Weight of assembly: 23 oz.
The entire unit is serviceable, but opening the bearing section between the base and the magazine could cause one to loose his marbles. The accumulator is pinned to the base and not glued.
The information on this page is very preliminary, and we welcome comments and suggestions for what else we need to put up. The first batch of cannons can be shipped out late in the week of April 19th to early the week of April 26th.
With the new design, it is quite possible there will be some issues. We will be taking care of issues as they arise in the field and reworking the turrets as needed. If something goes wrong, we really need to hear about it so we can take care of that unit and make sure it doesn’t occur in later ones.
Below, we have the turret sitting in the aft end of a Northampton hull, where the top of the plastic case is just about flush with the top of the lower deck (it is well below the deck in the fore part of the ship). The Brooklyn hull directly above it would have no problems with the turret. What cannot be seen in the pictures is the feed for the actuator, which comes out of the side of the plate opposite the accumulator. This feed is reversible, so it can come out either the left or right side. The accumulator in these pictures is one of the early test versions, so the shipped versions will be functionally the same but better looking.
Triple 3/16" turret inside the aft end of a Northampton Hull and alongside a Brooklyn hull.
End view of turret showing inlet port for poppet actuation. Turret rotation servo will be fitted onto aluminum cap with brackets.
The table below gives the pricing for the turret we have now and what we expect the others to be depending upon the number of barrels and size of the magazine. The chart does assume a 4 cubic inch accumulator. Larger accumulators are and additional $2 for a 6 inch or $4 for an 8 cubic inch accumulator. The design for the other parts is far enough along that we are reasonably confident in those prices, but it is possible they will change if we need to make a drastic change. BB and 3/16 ammo systems use identical hardware, but the 7/32″ and 1/4″ have several different parts between then (including barrels).
| Description | 2.5 inch magazine | 3.5 inch magazine | 4.0 inch magazine | 5.0 inch magazine | 6.0 inch magazine |
|---|---|---|---|---|---|
| 1 Barrel | $182.00 | $187.00 | $194.00 | $212.00 | $232.00 |
| 2 Barrels | $194.00 | $199.00 | $206.00 | $224.00 | $244.00 |
| 3 Barrels | $206.00 | $211.00 | $218.00 | $236.00 | $256.00 |
| 4 Barrels | $223.00 | $230.00 | $248.00 | $268.00 |
We are taking orders for the triple 3/16 cannons with the 2.5″ magazine now. We will make further announcements as we get other versions up for sale.
The choice of using a copper accumulator was not done lightly. The accumulator assembly can take significantly more pressure before bursting as compared with a PVC accumulator. It is my opinion that using the accumulator as a safety relief device is not a desirable option, as it is typically the second or third most potentially energetic component in the boat (after the main tank and maybe the batteries). If the accumulator can be made so that the lines burst or come off of connectors before damage occurs at the accumulator, then I feel the overall system is significantly safer. A higher pressure 1/4″ line is not going to do anywhere near the damage that an exploding PVC accumulator will do. Our accumulators will be tested to 250+ psi before going out the door.
In addition to making the accumulator stronger than the lines leading up to it, we will also have a pressure relief valve (PRV) that can be placed in line that is adjustable from 150 to 200 psi. The PRV weighs only 1.4 ounces, but will end up being slightly heavier due to needing to be placed in a 1/4 NPT port (unless it is put directly into something like the 1/4 NPT port in our variable regulator). Since the PRV vents at a maximum of 200 psi, burst tubing then becomes a secondary relief mechanism in the case of a drastic overpressure situation. A PRV is very reasonable in cost (~$6) and weight. We will be posting them on the website shortly, but we already have a few available.