Hovercraft Air Cushion Calculator
This hovercraft calculator will
provide the general lift air requirements of your proposed hovercraft design. Use
this information to assist in selecting the proper lift/pressure fan or air cushion size
for the gross weight you intend to support.
You should disregard the Estimated Fan Diameter and the Estimated
Lift Engine Power outputs because they are
not compatible with modern-day axial fan properties.
We use 4
inches of water gauge (in.wg.) static pressure (997 Pascal's) as our default pressure for
the air cushion, which supports 20.8 pounds per square foot, or 101.6 kilograms per square
meter of aircushion area. Generally, if your hovercraft weighs more than 15 pounds per
square foot of aircushion area or 76 kilograms per square meter, it is TOO HEAVY for the
air cushion area size you have provided which will require more engine power to support
the extra weight.
The shape of your hovercraft is
assumed to be rectangular. A length to width ratio of 2 to 1 is the most stable shape
for a hovercraft. If your hovercraft is of another shape (round, oval, etc.), then enter
an estimated length and width dimensions that will approximate the air cushion area of
your craft. Tip: Draw out air cushion shape to scale on graph paper, then
count the whole and partial squares.
Always use the measurement from
the ground contact point of the hovercraft skirt, not the outside, overall hovercraft hull
dimensions. The air gap you will specify is the distance between the ground and the
"contact point" of the hovercraft skirt, not the distance from the ground
to the bottom of the hovercraft hull, and is typically 0.25 to 0.5 inch. If you
double the air gap to, this will require double the air flow from your fan. If you
reduce your desired air gap to 0.25", the air flow requirement will be cut in half,
from from a 0.5" air gap. Using a 0.25" air gap is acceptable as well, and may
generate a higher aircushion pressure--a good thing.
Hovercraft lift calculator
Enter the required data in the
following fields, use the metric or imperial boxes, not both. When done, press the
"Calculate" button. The answers will appear below. Press the "Clear
Input" button before starting a new calculation.
Thanks are given to Alex Olshove for developing this
calculator based on James Perozzo's book, Hovercrafting as a Hobby.
Additional credit is given to Juergen Schoepf for incorporating metric units of measure
into this calculator.