Understanding Airplane Landing Force
Landing force is the load created while an aircraft arrests its vertical motion. The wheels touch first, but the whole structure reacts. Tires compress. Struts stroke. Damping absorbs energy. The cabin may feel gentle, while the gear still carries a large load.
A useful estimate starts with sink speed. This is the vertical speed at touchdown. Higher sink speed raises impact energy quickly, because energy changes with the square of speed. A small increase can create a much larger force.
Why Stroke Distance Matters
Stroke distance is the vertical travel available in tires and landing gear. More stroke spreads the stopping work over a longer distance. That lowers average reaction force. Short stroke makes the stop sharper. It raises load factor and peak load.
Real landing gear is not perfectly efficient. Heat, friction, tire shape, and damping behavior change the force curve. The efficiency value lets the calculator reduce usable stroke. A lower efficiency means less useful energy absorption. That increases the estimated force.
Using the Result Safely
The calculator gives an engineering estimate. It is not a certification tool. Aircraft design uses detailed tests, structural models, tire data, and regulatory load cases. Still, this method is helpful for study, concept checks, and early comparisons.
The load factor shows how many times the supported weight acts through the gear. A value near one means the gear mainly supports weight. Larger values mean touchdown impact is important. Peak force uses a multiplier, because real force is rarely flat.
Interpreting Gear Loads
Gear count divides the total vertical reaction between contact points. Main gear usually carries more than nose gear during touchdown. Use the load share field when the aircraft does not split load evenly. A taildragger, tricycle gear, or heavy transport may need different sharing assumptions.
Include a safety factor when comparing against a design limit. This does not replace formal margin analysis. It simply helps students and builders see how sensitive force is to mass, sink speed, and stroke.
For better results, use measured aircraft mass, realistic touchdown sink rate, and verified gear travel. Try several cases. Compare soft, normal, and firm landings. The pattern will show which input controls the largest change.
Use conservative values.