Throttle Simulator
The Throttle Simulator at https://rotorlab.app/sim lets you fly a build's numbers before you fly the aircraft. Move a virtual throttle and the readouts respond exactly as the analyzed model says they should: motor current rises as the cube of the stick, thrust as the square, both anchored to the build's analyzed figures. Start the flight clock and the battery drains at the power the current throttle demands, so you can watch a whole flight play out in seconds.
It is a first-order model for planning, not a flight log. Its value is intuition: where hover sits on the throttle, how fast endurance collapses when you fly above it, and what a VTOL's lift rotors cost in each phase.
Picking a build#
The Build selector at the top of the page offers Current build (from app) (the working build, see The working build), Example profile, and any Library: build you have saved. Choosing one re-analyzes it on the server and rebuilds the simulator around its figures, including the top-down drawing of the aircraft with its real motor layout.
The throttle#
The vertical throttle sits beside the aircraft drawing. Drag it with the pointer, or focus it and use the keyboard:
| Key | Action |
|---|---|
| Arrow Up or Arrow Right | Increase throttle by 2% |
| Arrow Down or Arrow Left | Decrease throttle by 2% |
| Home | Full throttle |
| End | Zero throttle |
| H | Jump to the hover throttle |
A dashed hover mark on the throttle track shows the stick position at which thrust equals weight, so you can see at a glance how much headroom the build has. The status tag over the drawing reads Idle, Hover, Climbing, or Descending as thrust-to-weight crosses 1, and the rotors in the drawing spin faster and the airframe lifts as you add throttle.
The readouts#
| Readout | Meaning |
|---|---|
| Thrust (g) | Total thrust at this stick, with the thrust-to-weight ratio; in cruise it becomes forward thrust with an approximate speed |
| Motor current (A) | Current drawn by the active motor group |
| Total power draw (W) | Power across all battery buses, including constant accessory loads |
| Rotor RPM (est) | Estimated rotor speed at this stick |
| Endurance at current throttle | How long the flight pack lasts if you hold this stick |
| Lift vs weight | A bar showing thrust against weight with the hover point marked; hidden in cruise |
The flight clock#
The right panel runs the battery in time:
- Press Fly. If the throttle is at zero it jumps to the hover stick, and the clock starts. The button becomes Pause.
- Pick a Speed multiplier: 1x, 5x, 30x, or 60x. At 60x a twenty-minute flight takes twenty seconds.
- Each battery bus shows a gauge with its remaining percentage and time left at the current draw; the bus driving the motors is tagged "motors". Accessory rails draw their constant power the whole time.
- When the flight pack runs out, the simulation stops, the throttle drops to zero, and a banner reports "Flight pack depleted, landed at" the elapsed time. Reset refills the packs and zeroes the clock.
Endurance here reflects the pack's usable fraction, not its full label capacity, matching the analyzer.
VTOL phases#
A build with more than one flight phase (a quadplane or tiltrotor) gets a Phase bar with three buttons:
- Hover: the lift rotors carry the weight; the pusher is idle.
- Transition: both motor groups run as the aircraft accelerates onto the wing; the current draw is the sum of both.
- Cruise: the pusher flies; the lift rotors are stopped, dead weight.
The drawing follows the phase: only the active group's rotors spin, and the resting group is dimmed. The hover mark, thrust, current, and RPM figures all switch to the active phase's numbers. A multirotor has only the hover phase and a fixed wing only cruise, so neither shows the bar.
Mission planner#
Below the flight clock, the same panel plans leg-based missions against the build's energy budget and answers whether a specific flight fits in the pack. See Mission planner for the full guide.