Member Model – Rowen’s Her Majesty’s Air Force Vessel “Seal”

After the shafts were correctly located, the motor mount position was established. I made up a mount using wood and aluminium plate. The motor shaft spacing is determined using the shaft centre lines. The longitudinal location can be measured from the shaft slope and height.

Two brushed, 550 type motors were then fitted to the mount, followed by the shaft couplings. The mount location can be fine tuned by slightly sliding the mount around until the motor and shafts could be rotated with the minimum force. The mount was then glued into place.

The shaft couplings used are steel, which tend to be noisy. I find that if a rubber or plastic sleeve is pushed over the coupling it quietens considerably. The inner coupling cavity/sleeve can also be filled with grease to ensure the joint is lubricated. I had earlier installed “oiler” fittings to the shafts for periodic lubrication.

I decided to try the Quicrun 1060 series ESC on this model, one per motor, to improve control. So far they work well, although the installation would be eased if the wires were longer.

I made up rudders by wrapping styrene sheet around a flattened brass rod and gluing together. The doubled over sheet was then cut to the rudder side profile and the section sanded to shape. Once compete the shafts were lubricated and inserted into the tubes. The rudder servo was fitted with a control linkage made up using old bicycle spokes and tested. I set the radio up to the “elevon” control sequence and tested the systems. Nice thing about brushed motors is everything usually works right the first time! No programming of ESCs etc needed either!

The hull was now watertight with the powertrain fitted; time for trial tests on the local pool. This may appear awry chronologically as I wanted to get the hull sailing properly before adding the superstructure etc as a winter project. I am using 3 S Li-Po batteries and I found the performance adequate. Nice bow and wave patterns, similar to the actual vessel photographs.

The forward / aft trim looks OK, although I was surprised by the draft. The model weights about 6 lbs and is already close to the waterline. I added ballast weights to see what would be needed to bring the model down to waterline. This shows that rather less that 3 lbs was available for the deck, superstructure and detail. I’m going to have to watch my weight again!