View Full Version : Hello & some advice please

Colin - n/a
27-Jan-06, 09:52 AM
Hi guys & gals

Im a 45 year old mature student who's been wanting to build a hovercraft for some time now, anyway I'm into my last few months at uni so I'm hoping to make a start this summer. Ive been involved in engineering for half my working life and as a cabinet maker for the other half. So:

Ive been looking at most of the sites for a while now, mainly Charlie Dixon's, Lazza's and Duncun's (nice btw) as well as some others building UH's, I feel that either the Viper or the Superwedge would be better for our needs than the UH's. We want to use the craft mainly on the sea (cruising and snorkelling) as we live on the coast and I will want to be getting out of it into the water quite frequently so I asume that the lack of a raided cockpit will aid this.

Is this the right idea? Obviously I know zip about hovercraft but also I like the idea of the raised nose on these too, seems like they will be more forgiving than the UH's pointy one.

What are the choices with engines? We want as quiet as we can, Ive seen that subaru seem to be the engine of choice, but are there sensible alternatives?

I'll leave it at that for now, have loads more questions but later me thinks



srn4 - n/a
27-Jan-06, 10:34 AM

The viper and the superwedge are very similar. From looking at Lazzas website the monocock structure of the viper looks slightly more substantial as it uses the centre seat and bulkhead as main strucutal feature whereas the superwedge does not (correct me if im wrong lazza!).

For someone who knows little about hovercraft the Viper plans would suit you well, the plans explain everything to allow you to build a nice looking hull. However the plans give you little or no information on what mechanical parts to fit as they expect you to buy their "power package". People on here will be able to help you figure out the mechanical aspect of things..looking at peoples websites, especialy photos will give you a lot of ideas.

I chose the subaru EA-81 engine because it was cheap and parts are really easily available. The engine is moderately heavy and large, but I dont see any reason why it wont work well in the viper. (some modifications are required to allow it to fit in the hull, if you need help with this just ask)

Another alterantive is the BMW k100 engine, I know this has been used in a couple of craft in the past.

The rule of thumb is that the engine needs to be 4 stroke, reliable and simple and ultra quiet..so unless you are an expert at maintaining engines dont choose an injected engine with complex electronics..the inevitable will happen!

The viper is designed to allow you to land on water and jump out and go for a swim...Getting back in again could be amusing but not impossible http://hovercraft.org.uk/images/icons/smiley_icons/icon_razz.gif

There is more than enough bouyancy to allow this.

Dunc http://hovercraft.org.uk/images/icons/smiley_icons/icon_rolleyes.gif http://hovercraft.org.uk/images/icons/smiley_icons/icon_eek.gif http://hovercraft.org.uk/images/icons/smiley_icons/icon_rolleyes.gif

Colin - n/a
27-Jan-06, 12:50 PM
LOL I'm used to hauling myself in and out of boats of all sorts,I was hoping this would be easier in my old age.

I'm pretty handy with the older type engines (our youngest car being 1971), so I was thinking along the same lines as you, I havent really gone into it thorourly yet but I havent actually seen a E81/2 for sale are they easy to come by?

How did you find fitting the duct on yours Dunc? I see you have used one that isn't from Nell, again something I was hoping to do http://hovercraft.org.uk/images/icons/smiley_icons/icon_lol.gif Did I mention being skint?

jar2 - n/a
27-Jan-06, 02:20 PM
Hi Colin,

If you are looking to cruise on the open sea then I would recommend you take a look at the Sevtec craft http://members.aol.com/sevtec/sev/skmr.html (members.aol.com/sevtec/sev/skmr.html)

You could also look at my site (below) - rather than me spout my opinions here again http://hovercraft.org.uk/images/icons/smiley_icons/icon_rolleyes.gif

Subaru EA81 engines were used in all of the MV pick ups built from about 1981 to 1993. If you live in or near a rural area then have a trawl round some farms - you will probably find a pickup rusting away in a corner someplace - they were very popular before Toyota came along. The EA82 is an OHC version of the EA81 and was used in the Subaru cars and estates before fuel injection came along - slightly heavier than the EA81. Alternatively, you could go for a more modern fuel injected engine - the Subaru Justy or Suzuki Swift (Geo Metro in the US) are pretty lightweight and reliable engines.

srn4 - n/a
27-Jan-06, 03:52 PM
The ea82 engine had a slight problem with cracking heads when it got to hot...just a thought!

I found my engine near gloucester. some chap collects the subaru pickups so he pulled one out of a truck for me.

55,000 miles, runs sweet as (Touch wood!)...250 with all electronics and exhaust.

My duct was from KM products, mounting it was a bit of a nightmare because trying to get it vertical was tricky. I can describe how I fitted it at some point if you like.

If you are skint then dont start building a craft...I have not finished yet and I am on three thousand and something pounds http://hovercraft.org.uk/images/icons/smiley_icons/icon_redface.gif http://hovercraft.org.uk/images/icons/smiley_icons/icon_confused.gif I was building on a budget!!

Ian Brooks - n/a
27-Jan-06, 06:01 PM
A word about noise...

This is less about engines ... just use a well silenced and above all light engine. You'll end up 4 stroke in the end because 2 strokes are very uneconomical (& more difficult to silence?).

To be quiet, you might want to consider the following points:

- Use less power - 35 hp should be adequate for a small machine

- There is some evidence propellers are quieter than fans (size for size).

- Use the largest fan/prop you can.

- Consider designs with separate lift fans.


lazza - n/a
27-Jan-06, 07:09 PM
If i was to do it all over again then chances are my preference would be the viper. I'm personally not a fan of the UH designs and i like the fact that the viper is already the same size as my extended superwedge without having to manually modify it.

Like Dunc mentioned, the wedge plans also leave the power plant details out of the original plans in hope that you will buy there power package. In my opinion for a quiet and reliable craft your certainly going to want to put a 4 stroke engine in.

Being skint shouldnt stop you building a craft because if its really something you want to do then i say just go for it .. but i will mention that if you want the craft even partily reliable then you'll be surprised just how quickly things start to add up.

Colin - n/a
29-Jan-06, 06:50 AM
I have not finished yet and I am on three thousand and something pounds http://hovercraft.org.uk/images/icons/smiley_icons/icon_redface.gif http://hovercraft.org.uk/images/icons/smiley_icons/icon_confused.gif I was building on a budget!!

Seriously! I had figured on around 2000 for a basic craft that could be upgraded with time and funds. I think perhaps that we might leave it another year or two before starting http://hovercraft.org.uk/images/icons/smiley_icons/icon_redface.gif I think after 5 years back in education I better concentrate on paying the mortgage for a while http://hovercraft.org.uk/images/icons/smiley_icons/icon_confused.gif

Cheers guys

srn4 - n/a
29-Jan-06, 09:38 AM
I wasnt meaning to put you off! but I can imagine nothing worse than getting half way through a project and then running out of cash.

I just checked and things are not quite as bad as I thought!!

Acording to my records I am on 2460...This includes an old caravan chassis to move the thing around. [I have not quite finished yet though!]

I have built my craft with the most basic componenets, the plan is, upgrade it once I have more money.

Sorry for the confusion there..not quite sure where the 3k came from http://hovercraft.org.uk/images/icons/smiley_icons/icon_confused.gif


team black - n/a
29-Jan-06, 06:19 PM
2000 would buy you a reasonable second hand two seater in need of a little work- like the one I was thinking of selling!

Ian Brooks - n/a
29-Jan-06, 10:01 PM
I reckon you could build a SevTec Scout for 2000 without too much problem.


jar2 - n/a
30-Jan-06, 07:33 AM
OK, as the resident Scout builder I just had to go and check!

The Scout cost 1286 to build. All of the parts used (apart from the fuel tank) were brand new (engine, prop, etc).

Surprisingly, when I checked, the UH18 only cost 1805 - not much more for a much larger/faster craft (the car engine used was only 50 which compared to the 300 for the lawnmower engine on the Scout which helped significantly).

The 18ft Prospector I am currently building is on target to come out around 2200 including hood, heated cabin, padded seats, etc (again a cheapo car engine helps).

If anyone wants a breakdown of the costs just let me know.

These costs obviously don't include the massive amount of self-provided labour http://hovercraft.org.uk/images/icons/smiley_icons/icon_smile.gif

Colin - n/a
30-Jan-06, 06:49 PM
I dont think the scout would be suitable for us as the payload is way to small, I'm around 18 stone, so that doesnt even allow for my kit, the Vanguard might be OK but are those side decks strong enough to withstand me clambering all over them on a regular basis? The seem very unsupported in comparison thi the superwedge or vipers which are boxed in to enclose the plenum.

I don't really want to buy a second hand one, whatever the saving/good sense or other, its the building part that is half the fun for me

Ian Brooks - n/a
30-Jan-06, 09:04 PM

My Surveyor is up to 1692 and I have all the major components. I expect to spend a few hundred more before completion. I did have the thrust engine already, apart from that everything was new.

The composite foam/grp structure is incredibly strong and stiff, I wouldn't envisage any problems stepping on the cloth-over-csm parts of the craft.