R/C Tank Combat

Field Artillery #FA008

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Type: 25 Pounder Armament: 25 pounder
Built: August 2014 Armor: None
Builder: Caleb Smith Rating: 10/1
Status: Operational Battles: 12
Owner: Caleb Smith Points Earned: 25,250
Call Sign: Unknown Points Given: 17,250
  • Novel rotate system
  • Servo powered elevate
  • Frame built by Steve Tyng

  • Click Photo For Enlargement (93 KB)

    The 25 Pounder started out as an idea after being to my first tank battle. I figured that an artillery piece would be a quick and easy way to get into the fun. So after about a week of looking through hundreds of different cannons, I settled on the QF 3.7in AA gun. After asking for help finding some plans, Steve Tyng offered me his half built 25 Pounder just so long as I finished it and brought it to battle. Let me say I jumped at the chance.

    Click Photo For Enlargement (166 KB)

    Click Photo For Enlargement (106 KB)
    An early mock up picture with the cardboard template of the splinter shield hanging on the barrel. You can also see the PMI Pirahna marker.

    For the rotate, I wanted to mimic the original cannon's ability to traverse 360 degrees on its firing platform. To do this, I used Steve's original idea of a spiked wheel on the end of the gun frame. The wheel is built out of plywood and is attached to a geared motor underneath the plywood plate.

    Click Photo For Enlargement (84 KB)

    Click Photo For Enlargement (198 KB)
    Here is a better photo of the rotate. The motor is mounted to a plywood mount that is glued to the piece of plywood. The motor itself is secured to the mount via zip ties. The cog wheel is attached to the motor by a coupler which passes through a 1/2" bearing which helps reduce stress on the motor shaft. You can also see the location of the ESC and receiver. This all can be easily accessed by just flipping the cannon onto its back.

    I then built the firing platform along with the centering attachment that goes from the gun frame to the center of the firing platform. The whole system works just like the original. All through its first day of battling it had no trouble traversing through the grass.

    Click Photo For Enlargement (100 KB)

    Click Photo For Enlargement (104 KB)
    To provide reliable firing, I used a door lock actuator to pull a lever, which pulls the trigger. The actuator is run by a servo and micro switch. Overall, this setup has proven to be reliable and quite fast.

    The easiest thing I could think of for the elevate was a servo. After a couple days of development, I came up with the setup pictured. The servo mount is made out of plywood, and was glued to the gun frame. The wooden piece at the top was glued to the marker mount. This setup proved to work pretty well. The precision of the servo allowed me to make some hits 75-100ft away. Out of all the systems, this is the shakiest. In the future, I plan to replace this with something sturdier, but for now it works fine.

    Click Photo For Enlargement (57 KB)

    Click Photo For Enlargement (227 KB)
    So after less than a month the 25 pounder was completed and participated in its first battle. It operated well all day with no breakdowns or failures, and I believe it earned the respect of some of the veteran battlers. See Bad Dept for details.

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