The Hovercraft Design Calculator

If you need to calculate the location of a air splitter within a duct then try the splitter placement calculator

The calculations that made this page possible were basically converted directly from James Perozzo's
book Hovercrafting As A Hobby and therefor, any credit should be directed to him. All I did was convert his work to JavaScript for your use.

If you don't know what to do with the output from this calculator, you should probably purchase James' book. It really is awfully handy if you're designing a hovercraft.

Thus-far, I have only completed the calculations for the lift-system. I will be adding other design stages (thrust, etc) when I get the time. Otherwise, it's an accurate alternative to punching buttons on your calculator. Keep in mind that this is beta release .00000000001a. ;-)

So far, this program assumes that your craft will be a simple rectangle shape with a slope or wedge at the front. The air gap is the distance between the ground and the bottom of the skirt (*not* the bottom of the craft).

Metric Conversions

American UnitsMetric Units
.394 Inches1 Centimeter
1.093 Yards1 Meter
.621 Miles1 Kilometer
.035 Ounces1 Gram
.0022 Pounds1 Gram
2.20 Pounds1 KiloGram
.264 Gallons1 Liter

CALCULATION STAGE 1 - Lift Requirements

Enter data in the following 4 fields and press the "Calculate" button. The answers will appear below.

Enter hull width in feet:

Enter hull length in feet:

Enter Amount of air gap required in inches (i.e. 0.5):

Enter Estimated Gross Weight of craft (fully-loaded w/driver) in pounds:


Information derived from input (stage 1):

Don't enter data in this area.

Approximate lift perimter (ft)
Total hover gap (sq. ft.)
Total cushion area (sq. ft.)
Cushion pressure (lbs/sq. in)
Expected actual air velocity (ft/sec)
Lift air volume (CFS)
Lift air volume (CFM)
Lift engine HP required
Est. Fan diameter (inches)


Enter data in the following fields and press the "Calculate" button. The answers will appear below.

Enter diameter of lift fan (inches):

Note: It is recommended to run a B&S engine at no more than 85% of full RPM (3600 RPM). Although this decreases
available HP, it increases engine life and reliability.

Enter desired engine power (HP):

Enter speed of engine (RPM):

Enter Number of fan blades desired:


Information derived from input (stage 2):

Don't enter data in this area.

Blade width [mid]"
Blade Width [base]"
Blade Width [tip]"
Tip Speed (ft/sec)

Disclaimer: You are using information derived from the above program at your own risk. In other words,
I'm not responsible for money lost resulting from the use of this page. It's for recreational use only.