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hovnov
12-Feb-10, 02:49 PM
Sorry about the very general nature of this post but here goes....

I am building a small hovercraft (appx 0.8m x 0.8m) to support a payload of up to 40kg (including self weight). I hope to have one fan for the hover and one fan for thrust and direction control. I am currently having no problems with calculating the cushion pressure and therefore the output power for the hover fan but....

When it comes to selecting the fan for the thrust I am struggling to find datasheets for fans which give me the required data from which to base my calculations in terms of exit velocity and flow rates etc.

If anyone could give me any guidance on this I would be very grateful. Basically I am happy with many of the methods its just getting the information on the fans.

Thanks

Stephen

Ewan Black
12-Feb-10, 04:19 PM
Try Keith Smallwood at Vortex Services, he sells Hascon fans and has data/selection software for them

Ian Brooks
12-Feb-10, 06:08 PM
0.8m x 0.8m would be a rather unusual length/beam ratio - more normally the ratio would be a minimum of 1.6:1 (ie 1.3m long and 0.8m wide), with cruisers more normally between 2:1 and 2.5:1. The reason I mention this, I was trying to work out what scale ratio you were running so that I could place the approximate fan size...

The length/beam ratio is important because it affects the wave-making drag - this is an important parameter that will affect how much thrust will be needed for operation on water. Long, thin craft have less drag than short fat craft!

Maybe you have a particular reason for the sizes you have selected?

Ian