推重比计算器

使用此推重比计算器快速获得准确的计算结果。

N
kg
m/s2

Thrust-to-Weight Ratio

1.4128

Net Vertical Acceleration4.0481 m/s2

Thrust-to-Weight Ratio vs Thrust

公式

Thrust-to-Weight Ratio

The TWR determines whether a vehicle can lift off and how quickly it accelerates.

Formula

TWR = F / (m * g)

  • *F* = engine thrust in newtons
  • *m* = total vehicle mass
  • *g* = local gravitational acceleration
  • TWR must exceed 1.0 for liftoff. Most launch vehicles aim for 1.2 to 1.8 at ignition.

    计算示例

    Saturn V first stage: 7 607 000 N thrust, 549 054 kg.

    1. 01TWR = F / (m * g)
    2. 02Weight = 549054 * 9.80665 = 5 384 000 N
    3. 03TWR = 7607000 / 5384000
    4. 04TWR = 1.413

    常见问题

    Can a TWR below 1 be useful?

    Yes, for in-space manoeuvres. Ion engines have tiny TWR (0.001 or less) but accumulate large delta-v over time.

    Why not maximise TWR?

    Very high TWR means excessive acceleration, which wastes fuel fighting drag in the lower atmosphere and stresses the structure.

    Does TWR change during flight?

    Yes. As fuel burns the mass decreases while thrust stays roughly constant, so TWR increases throughout the burn.

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