Flippers & lifters

Flippers and lifters win by control and displacement — turning opponents over, pinning them, or throwing them out of position — with little self-damage.

Lifter vs flipper

• Lifter: a slow, powerful arm (often a geared motor + linkage) that raises the opponent to unbalance, carry, or pin them. High control, low drama. A lifter with a second arm that clamps and lifts the opponent clear of the floor is a grappler / suplexer.
• Flipper: a fast actuator that launches the opponent up and over. Needs a burst of energy in a few tens of milliseconds.

Both live or die on ground game — a low front lip and good forks are half of the mechanism’s effectiveness.¹

Actuation methods (insect classes)

Method	Energy source	Pros	Cons
Servo / geared motor lifter	Battery	Simple, no extra rules, repeatable	Slow; limited flip height
Spring / elastic + motor reset	Stored in spring, motor re-cocks	Fast release, no gas system	Reset time; spring fatigue
CO₂ / HPA pneumatic	Compressed gas	Very fast, powerful full flips	Pressure-system rules, weight of bottle/reg/valve, leaks

Pneumatics in beetleweight are uncommon due to the mass of a compliant gas system and the extra pressure-system rules — regulated pressure limits, burst testing, secure mounting.² Most insect flippers are electric or spring-over-motor.

Design points

• Contact geometry: the flipping edge must get under the opponent. A sharp, low front lip and good wedge geometry is half of a flipper’s effectiveness.
• Reaction load: a hard flip drives the robot down and back — anchor the pivot into strong structure and keep enough front wheel load to not backflip yourself (unless self-righting handles it).
• Speed vs force: launching an opponent requires accelerating their mass in a short stroke — energy and power both matter. A lifter only needs force.
• Self-use: a flipper arm or lifter doubling as a srimech saves weight.
• Power the servo properly: a beetleweight lifter servo needs its own higher-current BEC (often 7.4 V) — signal to the receiver, power and ground to the BEC. Only tiny servos run straight off the receiver.¹

References

Footnotes

1. Ping, L., with L. Skotiniotis, I. Talbert & D. Tran. Beetleweights for Dummies (Fall 2025 revision) — builder-maintained beginner guide distributed via the NHRL Discord. Sections: Robot Archetypes → Lifters; Electronics & Wiring → Receivers and BECs. ↩ ↩²

2. SPARC Robot Construction Specifications, v1.4, 2023 — pneumatic and hydraulic (stored-energy) system rules: allowed working fluids, maximum pressures, and required safety features. ↩