# How to Calculate Weight and Balance

## How much to put where?

Manually calculating weight and balance is really the same as your basic high school math class.  Take the example below to warm up your brain and get in back into math mode if its been a while since you were in a high school math class.  After that, go ahead and watch the video above and follow along while taking notes to work through the example weight and balance problem.

Example:  If there is a box 1 foot from the pivot point and a box three feet from the pivot point, and the box three feet from the pivot point weighs 50lbs, how much does the box 1 foot from the pivot point need to weigh to balance the beam?

Answer: 50lbs x 3′ = 1′ x (some weight)

50×3 = 150 (means the box three feet away is acting upon the beam with 150FT-lbs of force, and the other box being only 1 foot away would need 150lbs to equal the 150ft-lbs.

If box X was 2 feet away from the pivot point it would need only 75lbs.

### Weight & Balance Terminology

Center of Gravity: The mass center of the aircraft. This is the point on which the aircraft would balance if suspended from a singular point.

Datum: Point from which moment arms are measured. Generally located at/near the firewall (between the instrument panel and engine).

Arm: The horizontal distance from the reference datum to an item’s center of gravity.

Moment: A force causing something to rotate. Equals an item’s weight x the arm.

Standard Empty Weight: The weight of an empty airplane including unusable fuel, and full hydraulic fluid, and engine oil.

Basic Empty Weight: The starting point for weight and balance computations. (Standard empty weight + optional equipment).

Useful Load: Total usable fuel, drainable oil, the weight of pilot, passengers, and cargo.

Payload: What you can carry besides basic empty weight and useable fuel (yourself, passengers, bags, and cargo)

Maximum Ramp Weight: Maximum weight the aircraft may be while on the pavement. Includes fuel for start, taxi, and run-up.

Maximum Takeoff Weight: Maximum weight allowable to initiate the takeoff roll.

Minimum Flight Weight: The minimum weight for flight as limited by aircraft design and CG requirements.