Poly Pipe RC Landyacht

I have been mucking around with model landyacht designs for about 30 years and here's the latest version. This one is the cheapest and simplest so far.

Construction
The body is PVC pipe, internal diam. 40mm, costing less than $5.00 from Fagg's Mitre10. I call it poly pipe but I'm told that's not strictly correct but the name seems to have stuck.

The angled steering head is a poly pipe elbow ($2.50) held in place by duct tape, no need for glue.

Mast, boom and rear axle are carbon fibre kite spars. ($9.50/m). Ali tube would also work well.

  • Wheelbase length 0.75m
  • Rear axle width 0.50m
  • Mast height 1.0m

    Wheels
    Finding the correct wheels is crucial to making a fast controllable landyacht.

    In-line skate wheels have great bearings but not enough grip. ($10 roller blades from Cash Converters gives 8 wheels and 16 skate bearings!)

    Plastic shopping cart wheels have great grip but no bearings. ($2.75 each from Fagg's Mitre10)

    So connecting the two together gives the perfect wheel. Care must be taken to ensure the skate wheel is dead centre in the larger wheel before screwing them together. I used a 25mm hole saw to remove the centre of the trolley wheels.

    Skate bearings slip snugly onto this axle. A simple wrap of duct tape holds the wheels on.

    Steering
    The front forks (and steering horn and rear axle bracket) are made from poly pipe, cut then flattened out and shaped with a paint stripping heat gun.

    The 80mm long steering bolt pivots in 2 holes drilled in the angled elbow.

    Cords tied to either side of the steering horn lead back to a standard Futaba 3003 servo.

    Mounting the steering assembly at an angle gives smoother steering at high speed.

    Sail
    The sail is made from ripstop nylon kite material. It is basically a flat piece of cloth, hemmed all the way around, with a pocket along the leading edge to slip over the mast. The leading edge has a small amount of curve to push some camber into the sail body.

    A thin perspex batten supports the wider head area. Reinforcing patches strengthen each corner.

    The boom slips into a sewn pocket in the front reinforcing patch (tack) and is held in with a line tied to the back reinforcing patch (clew). Holes in the sail are melted through using a heated coat-hanger wire.

    The sail downhaul line also holds the mast down into the internal nylon (chopping board) mast base.

  • Foot length - 42cm
  • Mast pocket - 93cm
  • Batten length - 20cm
  • Mast to boom angle - 80deg

    Sail control
    A powerful Hitec Mega Sail servo operates the mailsheet which alters sail angle. The standard Futaba 3003 servo might be OK for a smaller sail.

    The mailsheet leads through a stainless steel saddle which is bolted through the axle bracket to the body. This also holds the rear axle bracket in place.

    Inside
    The receiver sits in front of the sail servo. Batteries slip in the end of the pipe/body and are held in with a plug, which also acts as a mount for the ON/OFF switch.

    Keeping the weight right at the back gives maximum righting leverage (resistance to capsizing)

    In stronger winds extra weight (up to 1/2 kg of lead) can be strapped to the body between the saddle and the sail servo.

    Polypipe RC Landyacht video
    Onboard video
    Jersey Model Boats - Check out the model landyachting forum for their fleet of Polypipes

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