4wings.com Hovercraft development 47751 Michigan ave., Port Isabel - 78578 - Texas, US Tel.: (956)943 5150


Hovercraft development
47751 Michigan ave. , Port Isabel, TX, 78578
Tel:(956) 943-5150


Lift Calculator

The purpose of this calculator is to provide you with the general lift air characteristics of your craft.  You can use this information to help you choose the correct lift fan, or hull size, for the loads you intend to carry.  The shape of your craft is assumed to be rectangular.
Use the table at  page : " Hull construction "to get the craft size for your required payload.
 If your craft is of another shape, then enter length and width dimensions that will keep the area and circumference the same as your craft (use the measurements at the ground contact of the skirt-not the hull dimensions).  The air gap you will specify is the distance between the ground and the bottom "contact point" of the  skirt (not the distance from the ground to the bottom of the craft) and is typically between 0.5" and 1.0".
 If your craft will fly mostly over water and smooth surfaces - go for 0.5" to 0.75" - if the surface is rough ( gravel and riverbeds ) go for 0.75" to 1" hover gap. If in doubt take always the higher amount. Write your required CFS output down and recalculate under different weight conditions to get a feel for the required duct diameter. Also here - it is smarter to go for a bigger  ( 1 - 1.5") duct ( fan diameter ) than a smaller size duct - as you can change fan and engine relatively easy after first trials - but you want be able to cut the duct bigger without major work.

Have fun and feel free to distribute this file to all who need it

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.

Enter hull length in meters: or feet: 
Enter hull width in meters: or feet: 
Enter Amount of air gap required in mm (i.e. 13): or inches (i.e. 0.5): 
Enter max. gross weight of craft in kp: pounds: 


Results computed from the Input Data:
Approximate lift perimeter (m) (ft)
Total hover gap area (m^2) (sq. ft.)
Total cushion area (m^2) (sq. ft.)
Cushion pressure (N/m^2 = Pa) (lbs/sq. ft, PSF)
Cushion pressure (mm of water @ 4degC) (inches of water @ 60degF)
Expected actual air velocity (m/sec) (ft/sec)
Lift air volume (m^3/sec) (CFS)
Estimated lift engine power (kW) (HP)
Estimated fan diameter (m) (inches)



Once you are happy with your results .... download the Multiwing slector program from :http://www.kh-fan.de/ select 4z blades and save the 5Z blades in case your baby got a bit heavy.

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Related external links

Axial Fans by Multiwing

Centrifugal fans by Chicago blower

Hatzel fans