Thrust to Weight Ratio Calculator

This thrust-to-weight ratio calculator assists engineers in estimating the thrust-to-weight ratio of a vehicle. The thrust-to-weight ratio is crucial data when it comes to designing an aircraft, be it a smaller remote-controlled (RC) drone or a full-fledged passenger jet. For instance, the thrust-to-weight ratio parameter will tell us about the maneuverability of an aircraft. Read on to understand how to calculate thrust to weight ratio of different aircraft.

The thrust-to-weight ratio is defined as the ratio of the thrust available to the mass of the aircraft. It is a dimensionless quantity. In order to obtain the thrust-to-weight ratio, both values should be in appropriate units. For instance, if the thrust is in Newtons (N), and the weight is in kilograms (kg), the weight must be converted to mass to obtain the right answer. However, if the thrust is in pounds-force (lbf) and weight is in pounds (lb), the formula will give the correct answer. Mathematically, the ratio can be given by the equation:

The thrust-to-weight ratio can have multiple variations because of the different types of thrusts and weights. For instance:

• Thrust — This could either be available value during normal engine conditions, maximum available value, or in the afterburner conditions, where the thrust available is maximum.

• Weight — There are different types of aircraft weights, such as gross weight, the maximum take-off weight, weight at different fuel levels, say 50% or 100%, and empty weight.

The thrust-to-weight ratio can alternatively be defined as the inverse of the lift-to-drag ratio in cruise flight conditions. Mathematically, this is given as:

To calculate thrust to weight ratio:

1. Enter the appropriate thrust value.
2. Insert the weight of the aircraft.
3. The calculator will return the thrust-to-weight ratio.

Note: You can also directly choose the name of the aircraft or engine from the Aircraft / Engine dropdown options to find out its thrust-to-weight ratio parameter.

There are two modes of this calculator — single mode or compare mode; if you want to calculate the thrust-to-weight ratio of an aircraft, you can pick single mode. If you wish to compare the thrust to weight parameters of two different aircraft, you can pick the compare mode.

Using the single mode:
Estimate the thrust-to-weight ratio of an aircraft weighing 10,000 kg and having 2 engines capable of producing a thrust of 40 kN each.

1. First of all, since the aircraft has two engines, we find the total thrust available, such that:

   Thrust available = 2 × 40 = 80 kN

2. Enter the thrust available in the calculator as 80 kN.

3. Enter the weight of the aircraft as 10000 kg.

4. The thrust-to-weight ratio calculator will now return the value of thrust to weight ratio as 0.82.

Using the compare mode:
This mode is used to compare two different configurations. Say, for example, you want to compare the thrust to weight ratio of a General Dynamics F-16 Block 52 and HAL Tejas aircraft.

1. Set the mode to compare to display two sets of configurations to fill out.

2. Select General Dynamics F-16 Block 52 from the list as Aircraft 1.

3. Select HAL LCA Tejas Mk1 from the list as Aircraft 2.

4. The calculator will now calculate the thrust-to-weight ratio and compare them to tell you which configuration has a higher thrust-to-weight ratio.

Similarly, if you have your own data, you can enter them by selecting the last dropdown option for the aircraft or engine selection. Our tool will then calculate the thrust-to-weight ratio of commercial aircraft or drones, too.