Wood Lathe

There's a thing - won't the radio stuff stop working if it submerges? (Isn't that why they use sonar - radar doesn't work underwater?) Or is it for surface use only?

That's what eBay's for:

"....You'll need a tank...."

Michael

Nope it will dive just like the real ones.

If there is one question I get asked the most, its that. Radio waves are good for around 4m depth, much more than that and you can't see it anyway. However, having impurities in the water like salt or chlorine, prevents pretty much all the radio waves from penetrating by increasing the conductivity of the water. If you do go out of range/signal then you have failsafes to bring the sub up.The lower the frequency the better the penetration.

Michael

Thank you, Michael! I can now tell you that I am the author of the story of the Royal Air Force's involvement with the sinking of HM Submarine " Truculent" off Sheerness in early 1950. I was part of the mission.

Get a life, boy- in the real world of real men.

Norman

It will be for a Radio Control Submarine (Russian Akula Gepard). Pla is to make the fibreglass plug out of wood.

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Wouldn't it be easier to use a scaffolding pole with foam blocks t make the plug? If you want it in solid that is.

Otherwise reverse the process. use a female plug and a large balloo to press the fibreglass outwards. Then you could run the plug up out o

1mm sheet, rolled and wheeled to get the taper. The more pressure yo put inside, the more rigid it will become (to a point)

You can also split the hull, so you can lay the layups on the bladde before wetting out, joining the hulls and inflating the bladder. I might even be worth seeing if someone can supply you with prepreg o try your own resin injectio

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1.5 tonnes ? I make it 770 kg.... still not something I would want to drop on my toes...

Is this ( 4.7 long 0.6 diam ) the finished size or the " blank "

Will the blank be reasonably balanced

What appears to be needed is a sturdy tempory frame to hold a pair of robust centre points, might hiring some scaffold poles to make a frame from be a way to go ?

Does the mould really need to be made of solid timber? Couldn't you fabricate a hollow one from boards supported by ribs in the same way as real boat hull is made?

Cliff.

Jonathan,

That will be the size of the blank.

Not sure about scaffold poles, easy to do though....Anyone recommend this or see problems with it?

Thanks

Michael

When I check my numbers (4.5m long), I get 750kg...

I take that to be the blank, on the assumption that the sub won't be log-shaped.

I'm not sure the clamping would be strong/tight enough if the balance isn't ideal. RHS with right-angled brackets through-bolted (and possibly welded) strikes me as more rigid and reliable.

See other post - I wouldn't trust the clamping.

Thanks Wally,

Norm, do you have an opinion on this?

Michael

"Michael" wrote

to carve a log that size down to a submarine hull shape is a huge amount of work.. and actually achieving the shape on a home made jig will be very difficult.

for a fibre glass hull you could make a series of thin plywood bulkheads, slotted on to a pair of thick central forms set at right angles. fill the gaps with foam, ( polyurethane ) and lay up the fibre glass on the foam. It would be easy to model blow tanks, deck, conning tower etc, which it would not be possible to do with a simple turned log.

Well if I have to use another method then I will, but I really want to exhaust the lathe possiibility first.

Michael

More likely it'll exhaust you! Fabricating your buck is the best bet.

I guess I could, but as the hull is a teardrop shape makes slightly more difficult.....Also as they hull is so long I'll need to have lots of ribs....

Still a possibility though..

Michael

Why not turn it out of something much lighter, like some kind of rigid foam? Then coat it with something that sets hard and smooth the surface in the lathe.

It's very expensive to buy. I've already considered it and from memory the cost was around £500+ for the foam alone. You then have the lathe setup costs on top of that.

I've been talking to my Dad, and he has some scaffolding bits lying around. Can anyone see a problem with mounting the wood vertical as opposed to horizontal? Bit like a huge kebab ;-)

Michael

If something breaks, there will be a 15-foot tree trunk spinning amok. It might be harder to secure the top than it would to have both ends bolted to the floor.

Two pack foam to do this job can be got from Strand or Allscot or your friendly neighbourhood fibreglass supplier(see yellow pages) for about =A350, so there's no reason not to mould your own foam blank. Make a appropriately sized open top cardboard or hardboard box with a scaffold bar or a broomhandle mounted centrally on the long axis, mix up your foam goop, pour it in and stand clear; very amusing to watch but very sticky, ask me how I know. I did this several times at Uni to make odd shaped foam blanks for model making, albeit on a smaller scale. Carving foam is a LOT easier than even soft wood, so your makeshift lathe has less stress on it and is cheaper and easier to construct.

Hope you're going to keep us informed of progress whatever method you choose; it sounds interesting.

cheers, David