Hovercraft vibration noise problem

[tnorm12]

I have built a 3' by 4' hovercraft (with rounded corners) out of plywood with a pond liner bag skirt. it it powered by either 2 battery operated leaf blowers or 1 plug in electric leaf blower. I have encountered a problem with both power sources. The hovercraft makes a loud vibrating noise when I stand/sit on it. It sounds like when you vibrate your lips together but much louder. With nobody on the craft there is a very small noise and with somebody on it its much louder. On the bottom there is a rectangular piece of plastic in the middle (16" by 4") positioned so that is 16 inches to every side (a little longer to the corners). There are 6 approx 2" holes around the middle (2 on each long side and 1 on each short side). Any suggestions of how to get rid of the noise? I assume its from not enough holes/bad positioning of the holes but i don't know.

 

[Drakkith]

What is the noise coming from? The skirt?

 

[Uglybb]

Fan designed for high volume and fast rotating is always going to have servere noise problems as the pressure jacks up and down at the skirt.

You are best talking to experts in the area like the hovercraft club in uk.
http://www.hovercraft.org.uk/archive/index.php

They have active forums with people who would have hands on solutions most likely.

 

[tnorm12]

yes the noise seems to be coming from the skirt. I noticed when turned on the skirt is flapping/ vibrating. The noise becomes louder and the vibrations quicker when I step on the craft

 

[tnorm12]

Uglybb you said it will always have sever noise problems but the thing is in my 1st prototype i built straight off the basic online model (round 4' diameter, leaf blower, plastic 6 mil sheet for skirt, 6 holes evenly spaced around the center, bag skirt) and there was not the same vibrating/rumbling sound. Thanks for the link

 

[Uglybb]

I haven't played with hovercraft for way too many years!

Admittedly my early attempts I didnt even create a proper bell chamber it was just an open cavity with a skirt and they were particually loud with two counter rotating propellers for lift.

Having a good model to start with would definitely been an advantage!

Times have changed understanding of the problems and solutions are much easier to find because if the internet ... enjoy :-)