As a pilot operates an aircraft, the force of gravity and the weight on board affect its performance, handling and safety. Maintaining a stable center of gravity at all times is crucial for compliance with flight safety standards and optimal control.
Once the essential onboard equipment, fuel and passengers have been accounted for, it may be necessary to add or distribute further weight to bring an aircraft within the allowable weight range. Ballast can be permanently or temporarily installed to aid this process.
Metal ballast is typically used in all types of aircraft, including military and commercial operations.
Why tungsten heavy alloys used in aerospace ballast
Although ballast is often made of lead, tungsten alloys have proven much more popular in recent decades, thanks to its higher density at a lower volume. This refractory metal has a density of between 16.8g and 18.75g per m3, approximately 50-60% heavier than lead.
The resulting component is only approximately 60% of the size of its lead counterpart at the same weight. This means that ballast components can be 40% smaller, which widens possibilities for distribution within the aircraft, especially in the nose or tail areas of the plane where space is restricted.
Tungsten alloys are also used in the simulation of aircraft loading during flight tests, to determine precise locations for ballast to be situated under varying payload conditions. In any case, tungsten heavy alloys can lower the overall aircraft weight. Ballast components should comply with AS9100, an internationally recognized quality standard set out by the aerospace industry.
Centre of gravity
The centre of gravity (CG) is the point at which the weight is concentrated, and it must be shifted to within an optimal range before the pilot can operate the aircraft. The manufacturer determines the allowable weight range for each individual aircraft.
The objective is to balance the weight appropriately so that the plane is neither nose-heavy nor tail-heavy. Types of weight that influence the center of gravity include the structural weight of the aircraft, onboard equipment, passengers, air crew, fuel and cargo.
Adding ballast to the balance
If more weight must be added to maintain an allowable center of gravity, ballast will be added, usually as far forward as possible (or as far aft) to reduce the amount of total weight required.
Since aircrafts have limited space available, compact yet dense types of ballast are preferable in the aerospace industry. Tungsten alloy is high density and small volume so it is considered to be the best material for aircraft ballast.
Permanent ballast contributes to the aircraft’s empty weight, since they are usually bolted to structure. It is common to use lead plates or bars for this purpose. Permanent ballast must be secured and labeled appropriately so as to avoid accidental removal from the aircraft.
Temporary ballast can be added and removed as required, and is therefore labeled with its purpose and total weight. Once removed, the aircraft’s balance and weight must be checked again.
Where to find tungsten?
If you are interested in tungsten, please visit Matmatch to find more about tungsten characteristics, chemical composition, and properties. We collaborate with several major tungsten suppliers, which you can find on our suppliers page.
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