Land Hovercraft Build Log: Skids, Blower Tuning and Surface Transition Testing.

Land Hovercraft Build Log: Skids, Blower Tuning and Surface Transition Testing.

I started this land hovercraft as a weekend project to learn about low-friction contact points and blower tuning while keeping the design simple enough for a garage build. I used a 1.2 metre plywood deck with a shallow peripheral plenum and a central skirt ring to keep the weight low and the air distribution even. I planned for a single centrifugal blower to feed the plenum and two simple skids front and rear to guide the craft through grass and tarmac. This log records the steps and measured tweaks that made the prototype usable and repeatable for hobbyist builders.

The parts list for the prototype was compact and inexpensive and included standard hobby and DIY components to keep repairs easy. I chose 6mm ply for the deck, 3mm closed-cell foam for the skirt base, 10mm polyethylene sheets for low-friction skids and a 12 volt centrifugal blower rated at about 300 cubic feet per minute for a 1.2 metre platform. The practical tools I used were a jigsaw, angle grinder with flap disc, heat gun for shaping the skirt and a digital manometer for measuring plenum pressure. I documented CAD mock-ups and photos while I built a test rig for flow measurement to assist with tuning.

Designing low-friction skids needs both material choice and geometry to be right so the skids support lateral loads without introducing significant drag. I cut the skids from 10mm polyethylene sheet and formed a slightly convex profile to reduce edge catching on rough surfaces. Each skid is mounted on a pair of small aluminium brackets with spring spacers so the skids float slightly with the deck, allowing them to ride clear of the skirt at full lift and touch down progressively as lift falls. I chamfered the leading edges and polished them to reduce friction and found that a 20 to 30 degree bevel on the nose dramatically reduced snags on gravel and short grass.

Blower selection and tuning proved to be the single biggest variable affecting behaviour and controllability, so I spent time measuring flow and pressure rather than guessing. The centrifugal blower I chose delivered the best compromise of pressure and volume for the plenum size but needed a simple variable controller to avoid overloading the motor and to manage cushion height. I built a PWM controller with a current limiter and added a bleed valve to the plenum for coarse lift control. Using a digital manometer I calibrated the blower to maintain about 10 to 25 millibars of plenum pressure for steady lift, and I recorded blower duty cycles against payload to create a simple lookup table for throttle settings during testing.

Surface transition testing is where a land hovercraft proves itself, so I staged tests across tarmac, compacted gravel and long grass to examine how the skirt and skids behaved at changeovers. I ran repeated passes and measured lift, leakage and skid wear while noting the pilot inputs required to cross from one surface to another. The skirt design uses segmented fingers with small overlap to allow the craft to deform at the contact zone, and adding a short peripheral channel to the plenum reduced edge leakage during transitions. I logged vibration, minor deflections and skid temperature after multiple passes to check for excessive friction and to fine tune the bevel and mounting compliance for the skids.

Troubleshooting and incremental improvements were straightforward once measurement routines were standardised, and I recommend other builders adopt the same approach with a simple checklist and test diary. Key adjustments included slightly increasing skirt finger length to reduce edge leakage on long grass, fitting abrasion strips to skids where they contacted tarmac most frequently and refining the blower PWM ramp to avoid sudden lift spikes when moving over bumps. For those who want to follow the full parts list, CAD files and photo diary I kept everything on my project page at watdafeck.uk which helped me avoid repeating mistakes and made sourcing replacements straightforward.

Final thoughts are that a small land hovercraft is an excellent electronics and fabrication exercise that rewards careful measurement and iteration, and that most problems can be solved with modest tools and low-cost materials. Start small, test on a variety of surfaces and focus first on reliable low-friction skids, then on blower control and finally on systematic surface transition testing to close the loop between design and performance. With patience and measured tweaks a hobbyist can achieve a stable, controllable craft suitable for light loads and educational demos.

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