« Reply #5 on: May 09, 2021, 10:54 am »
Yep, top secret ;) but the various contributors aren’t far away. There’s a lot of hard work in getting the fan right. Fan types, ratio, blade number, angle etc all need to be worked out. You can get so far by calculations but experimentation is the only way to get the final answer, which will also depend on other things such as local hull restrictions etc.

One problem is that there are no purpose designed propellers suitable for hovercraft. We either have fans designed for very low forward speed or props designed for jig forward speed. I’m hoping that interest in small eVTOL aircraft will result in some very suitable props becoming available in the future.

My advice would be that a useable cruising craft will transfer more power to lift than you might expect!
Ian Brooks
Gloucester, UK

« Reply #4 on: May 09, 2021, 9:47 am »
I think it's top secret Gavin  ;D

I would hazard a guess and say they are 1510mm looking at the photos of the Otter.  Looks like they use 4 X 7W blades on some and 3 x 7W blades on the earlier ones in a 6 blade hub.  According to K&M products website, max fan diameter for a 6 hub is 1510mm

Mind you I could be talking a lot of b******s  :-\ ;D

« Reply #3 on: May 09, 2021, 9:36 am »
I think the lift is much the same as most sevs at 24" or at least close to that.
There's no such thing as bad weather, you're just wearing the wrong jacket!!

« Reply #2 on: May 09, 2021, 6:29 am »
 No-one? Or is it a secret?

« Reply #1 on: May 02, 2021, 2:51 pm »
Just wondering, what are the size of the fans on an Otter?