Originally Posted by JeremyBB

Hi Pitpup - It looks pretty good to me . From the size of the lift duct, you must be using an impeller as did the real things. Do you have an idea of the lift thrust you will get in relation to the weight of the craft? Are you building to a specification which someone else has already used or are you working from scratch?

A member of the Model Hovercraft Association in the UK is also building a 1/12th scale SRN6 and I think others have done before. I will let him know what you are doing and he may well have good advice to pass on.

Hi Jeremy.

Yes im having a go with a lift fan impellor, the information for which i got from the book that Mark Porter published. If you look back on this blog you will see some pictures of it which i posted some time ago.

Regards
Pitpup (steve)

Originally Posted by JeremyBB

Out on the open water for the first time. I have fitted a baffle in the air duct to try and counteract the turning motion when stationery. Seems to work at least to some extent. U-tube video: http://www.youtube.com/watch?v=Mms2NS3nbgU

Great vid, do you have one of it operating on land ??

Originally Posted by PITPUP

Great vid, do you have one of it operating on land ??

No run on land yet - I still have to find a suitable location, smooth and traffic free. Hovertravel operated only as a ferry at sea with ramps onto land at either end of her crossings.

A second run at Black Park today almost ended in disaster. The lift prop flew off and she settled gracefully onto the lake.

SRN6disaster060912 (0 min 18 sec)

Fortunately, the box structure containing the electrics is water tight so she stayed afloat and the thrust prop was still able to get her back to land. That will teach me to check the prop fixings before every run. There is a fair amount of vibration so things can work loose. We live and learn!

there should be very little vibration what size prop have you used and did cut it dow even a new prop that has not been cut down needs to be balanced

Originally Posted by HoverTim

there should be very little vibration what size prop have you used and did cut it dow even a new prop that has not been cut down needs to be balanced

Prop is an 8*4 cut down to just less than 6". It was balanced and I have also balanced the replacement. We shall see how it goes. Maybe it's more noise than vibration.

whats the fit like on the prop adapter if its a bit loose then you can wrap some masking tape cut down to about 10 mm wide this allows the prop to sit tight on the shaft and not wobble i would check everything on your lift motor setup as the prop should not sheer off

Originally Posted by HoverTim

whats the fit like on the prop adapter if its a bit loose then you can wrap some masking tape cut down to about 10 mm wide this allows the prop to sit tight on the shaft and not wobble i would check everything on your lift motor setup as the prop should not sheer off

3mm prop adapter on 3mm motor shaft. Seems to tighten up OK. I don't think there's any room for masking tape. Tried with a new prop today which shattered after a few minutes. I don't understand where the nicks came from as I only tried the craft on water. However, as you will see, it shattered which is probably what happened to the first one . Cheap Chinese rubbish from Hobby King?? - most of their stuff is excellent and good value so I have no complaints so far as rthey are concerned. Maybe their props are an exception. I will try with a genuine APC prop next, hopefully with better results.

Definitely recommend APC - especially the 'E' variety specially designed for fast electric motors. Another thing might be to put mesh inside the intake opening to stop dirt getting in.

I am making SR.N5 one using Porter's plans and lots of fotos. Here it is. Materials are 3mm plywood - boxes for fruits:-) and balsa. Scale is 1:16, it should weight around 1kg.
The main problem for me so far is finding 3mm shaft for thrust prop. I heard one can be found in old cd/dvd drives but idk where to get one.

I used 3mm piano wire, cut it to length then put it in a drill and sanded it till it fit small ball race bearings I had from a helicopter project. Seems pretty straight and works fine.