LCAC

[lliw180]

Hi all

I was thinking of starting another build once i get a bit more work done on the dukw . As i Love amphibians i thought why not an LCAC ( for thoes of you who dont know LCAC stands for Landing craft Air Custion ) its a large hovercraft used by the US Navy for lading marines. I have sean a few models made of one of theas on youtube. Now what i want some help with it where to start as as far as i can see i have to options

A) by a toy RC hovercraft ad modifie As in new deck more powerfull mortors ect modifie a badly made toy to be more relabale and look like an LCAC
Pro i dont have to buggerrise around trying to make a skirt using rubber and gule and modls ect witch to me sound like a nightmare. However im willing to look in to a scratch build asuming i can find the rite rubber gule and can be confident i can enginger a scale model working acurat looking hover platform.
Con scale and how acurate the shape and size will be as far as i can tell moding will limit me to around 400mm long

B) Scratch building
Well i have done a Resonbly acurate Dukw lol. When i was a lot younger i had a toy rc hover craft and the hover part of it seamed to be a skirt made from what would turn out to be rubish rubber with holes punched in to the bottom of the skirt witch sat over a polly strirean horse shoe shape bace with holes cut for air flow. so the simpekt dalton for scratch building would be a MDF or ply deck with two lift fans one forward and one aft. a plystile hose shoe sahped bace for the skirt with chanels and ducking for air flow with a rubber skirt with hols punched in it

I would prefer scrach building as i love it but i have NVER done anything like this before

Any thought sagstions of exprance anyone on here has had would be a grete help

[hawkeye3guns]

A friend of mine built a scratch hovercraft for fun and he got all his ideas from looking at the web and checking the sports homebuilt hovercrafts sites he said there is a lot of designs and ideas out there that could be minuturised into models.

[lliw180]

Hey Denzel how going mate long time. Tonight im gonna do a proof of concept and if i can make it work ill prob go scratch building A) as i wanna go 1/35 scale there is nothing i can realy mod and B) the principal is simpal enough so plane for tonight is I have got my self a light powerfull computer cooling fan witch is what people work with for rc hovercraft on youtube. I have got a bbq try witch i will cut a hole in stick the fan and try lift it if that works ill get a pecec of mdf cut hole make a skirt out of plastic bag with a few holes in it and try lift that and from there ill just go biggger and bigger to work out how many lift motors ill need and how power i will at the lest do some pics maby even a video

[hawkeye3guns]

Hi mate I'm doing good. I talked to one of our local model boaters and He offered a tip for your hovercraft. If at all possible stick to a single lift motor. If you start using multipule motors you can run into all sorts of balance problems, (2 identical motors but when running gave out differant lift properties) He built a SR7 ferry hovercraft with 2 motors to start with and just could not get a proper balance, and ended going back to a large speed 700 motor driving a 5" 3 bladed aircraft prop set in a duct to get the lift. He also said he used a push bike innner tube cut lenght ways for the skirt attatched at the top and then looped a single strand of fishing line around the bottom of the skirt to gather it in. He is looking to see if he has any photo's of the set up and if he has I'll pm you
Denzil.

[tomhugill]

A 1/16 scale one sold on eBay a while ago. With something like this you really need to be using brushless motors and lipo battery's to save space and weight.

[lliw180]

for the lift motor i was hoping to use computer cooling fans for the lift egines. A) they are a well balanced self contained unit B) you can put 12v threw them no problem c) belive it or not they are surprisingly powerfull D) relativly cheap. Working at 1/35 scale will give me somthing that is 754mm long by 408mm wide. As far as blaence is concerned i will be using 4 lift egines 1 in each corner. The heavy part of any electronic model is allwase the batteries witch will be placed in the midel. If i use 1 lift engine im not sure where to put it if you look at a real LCAC you will the the deck is a flat deck that i think may be covered in asphelt as it carrys tanks ect. So the only way i can see to do it is to have more than 1 lift engine. But yeah Denzil those pics would be apreshated ( also mate i aded a bit more to the dukw thred )

Any way first night of R and D last night and when i say R and D i mean one mad Australian drinking beer cutiing up bits of cardbord and papper plates and plastic bag to make a curd hovercraft as a proof of conspet at least.

Mk1 was a bbq try with a hole cut at the top for the competer fan i only ran 7.2 v threw it and it hovered a little no much but a bit Mk2 was a plastic tup sealed with a lot of tape dint hover at all Mk3 was trying it with 12v no better Mk4 was sticking a bit of plastick over the bance of the fan with a few hole didnt work Mk5 finaly a result a plastic plate with a hole cut for the fan stuck on pumped 14.4v from a drill hovered realy well i then set about finding how much it could lift. so i added AA 2 at a time and it lifted 9 but only just so one lift motor will cofortably lift 6 AA s the mk6 was a peace of card bord with a hole cut at the front with a skirt fationed from a garbage bag and it inflated a and lifted like real one. but the skirt was a bit here and there so i rouned the front made the skirt a lot more slack and the mk 7 worked realy well and i got a fair bit of lift. So what i have laent is the skit is of utmost importance. and make the lift eangine mutch more effective at lifting this x4 should be plenty of lift. Power i have sean theas bateries that are the same size as AA but throw out 3v and fair bit of amps

[lliw180]

the night efforts

[lliw180]

wow and real LCAC is 26 meters long a 1/16 would be huge somthing il have to youtube

[lister fiend]

Hi lliw,
If the top gear monkeys can make a hovercraft out of a transit van
I'm sure you can pull it off

[Crispy]

I've been toying with something similar and thought I'd share a few things to consider.

I think your lift fans won't have the oomph needed, they may work on smooth surfaces (any weak fan will eventually inflate the skirt) but as soon as you travel over even the slightest bumps the "air cushion" will deflate and those fans will take way to long to reinflate it, killing any forward movement and leaving you stranded. Ideally you want to be over inflating it so the excess is constantly being blown out, think of of a full size hovercraft and it's surrounded by water spray. Perhaps a hair dryer ducted fan would be more appropriate given the cubic area you'll need to fill.

As for a rubber inner tube skirt, at 1/35 it's gonna be way oversized and not flex very well. I would be thinking to use nylon material like they make kites from, or if you can find it a waterproof jacket? Either way the layout of an LCAC will likely mean you'll need two lift fans and two propulsion fans. Obviously there's the rear rudders but you'd also benefit from the forward blowers to help control the steering, so you may need 6 fans in all which means some kind of RC mixer would be a big help.

Another thing, hovercraft are particularly hard to steer or even keep straight so I was thinking to make mine naturally buoyant and have a kill switch on the lift fans. That way if I'm heading for disaster I can drop it on the floor too stop it moving but it I know it won't sink.

Saying at that it'd be damn good to see the thing in action tho especially if you can drive it across a lake, run it up a beach and then have a tank drive off

Nic