Hydraulic platforms move the seat with fluid-driven cylinders fed by a pump; electric platforms use servo motors driving screw actuators. For racing simulators, electric is the practical choice: no hydraulic oil, pumps or leaks, lower noise and power needs, and precise digital control. Even full-flight simulators, long associated with hydraulics, are now certified with all-electric motion. SimsForHire's full-motion rigs use electric SIGMA Integrale 2DOF/3DOF platforms.
How each one works
Hydraulic
A pump pressurizes fluid, and valves direct it into cylinders that extend and retract. Classic flight-simulator motion bases use six actuators in a hexapod (Gough-Stewart) layout, and those actuators are commonly either hydraulic jacks or electric linear actuators (background).
Electric
A servo motor turns a ball screw, which converts rotation into linear motion. SIGMA Integrale's DK2 actuators, for example, use American-made servo motors and ball screws with a 2-inch (50 mm) stroke, and the company says they run for years without lubrication (SIGMA Integrale).
Side-by-side
| Hydraulic | Electric | |
|---|---|---|
| Power source | Pump and pressurized fluid | Servo motors and controllers |
| Maintenance | Fluid, seals and the risk of oil leaks | SIGMA cites no lubrication required for its DK actuators |
| Noise and power | NASA lists high power consumption and noise among hydraulic drawbacks | Lower; SIGMA's DK systems run on a 75-volt DC system |
| Control | Valve-controlled | Digital control loops; Moog cites loops "that do not drift" |
| Where you find it | Historically common in simulators (NASA, 1975) | Sim-racing platforms such as SIGMA's, and Level B to D certified flight simulators (Moog) |
Sources for the table: NASA, SIGMA Integrale, Moog.
What the evidence says
- The hydraulic drawbacks are long known. A NASA paper on simulator control loading described replacing the "more common hydraulic actuators" with electric torque motors to avoid high cost, high power consumption, noise, oil leaks and safety problems (NASA Technical Reports Server). That paper covered control-loading systems (the forces on a pilot's stick and pedals) rather than whole motion bases, but the trade-offs are the same in kind.
- Electric motion reached full-flight simulators. Moog says it designed the first 4,500 kg (10,000 lb) electric motion platform in 1994, offers all-electric systems certified to Level B, C and D, and reports more than 2,000 electric motion systems installed (Moog brochure; Moog E60 brochure).
- Sim-racing payloads are modest. A loaded racing seat weighs hundreds of pounds, not tons. SIGMA rates its DK2 at 500 lb and the DK2+ at 800 lb, and offers the DK2+ for commercial uses such as sim centers (DK2; SIGMA).
When would hydraulics still make sense?
For a racing seat, rarely. The payloads involved are within what electric platforms are rated for (above), and electric actuators avoid pumps, fluid and leaks, which also makes them practical to move between venues and set up for a day.
What matters more than the actuator type
- Motion software: how telemetry is turned into pitch, roll and heave cues. SIGMA describes converting surge to pitch, sway to roll and running a heave layer (SIGMA Integrale).
- Degrees of freedom: how many axes the platform moves on. See our DOF comparison.
- Travel and speed: SIGMA lists 2 inches of travel for DK2/DK2+ and 6 inches for DK6+ (SIGMA).
For how motion creates the feeling of acceleration, read how motion platforms create G-forces.
What SimsForHire uses at events
All 10 of our full-motion rigs use SIGMA Integrale 2DOF/3DOF motion platforms with electric actuators; none are hydraulic. Every rig we rent is full-motion. We deliver, set up, staff and tear down at corporate events, trade shows, private parties and brand activations, and we sell and lease simulators. Full-motion rigs are $2,750 per day, plus tax and insurance. See pricing or call (754) 228-5654.