Hovercraft

[Mike Bortfeldt]

I use a 6 hp vertical shaft engine for lift, which I run at about 75% full speed. This easily provides 900+ lbs of lift using a 26" diameter 4-blade fiberglassed wood prop. The prop was purchased from Universal Hovercraft "preshaped", which basically means that they are rough cut and require finish sanding, fiberglassing, and balancing before use. They also sell plans to build your own if you want to take that route (much cheaper - but more work). The setup of my lift fan is not all that different than from your picture (although I use a duct). The lift engine is in front and about 20% of the lift duct opening is directed into the bag skirt with the remaining 80% is just directed under the hovercraft. The bag skirt itself is attached on the outside (obviously) and the second attachment point is about 9"-12" in from the outside (9" or so on the sides, more like 12" front & back – the difference is most likely due to the hull design). The skirt material is typically vinyl-coated nylon, however, probably any type of material that is not too porous to air will work (tarp?). The durability will probably just be a little less.
You can also get away with only the two center rudders as the ones on either end are not going to add a significant amount of additional turning capability and it should simplify the steering system a little. While mechanical systems are not my area of expertise, I think you will want more than a 90-degree wrap angle on the engine for the belt or you may get some slippage.
I hope you can find some useful information here. It's looking pretty good.

Mike