shark, dorasl fin, something that will do this job!

Hi all,

new member here, I know nothing about rc subs, but do know about rc boats, and helicopters. I have a real nice scale rc model of Orca, jaws boat, very detailed, you know what is coming, I need a forgotton project, something lurking under the bed, or in the attic, that will never get used again, it needs to submerse the height of the dorsal, go forwards, left and right.

I dont have the time or knowledge to build from scratch, so am looking for a smallish sub I can fabricate a dorsal and top half of a shark body on, so I can compete the set, Orca, and Jaws!

Sure you have heard all this before, I have tried various boat forums, even tried to contact a guy who successfully built a very good shark, I get nothing back, I have been pointed in your direction, hopefully someone can help. I reckon an mmb would be a bit big, but would do, the boat is about 40 inches long, somewhat limited funds, hence wanting second hand

Thanks

An interesting challenge this one!

Maybe best to consider what effect you are trying to achieve. A small r/c shark cruising around and making frequent appearances is one option. However:

- It will cost a lot (several hundred ££s)
- You will find it quite challenging to operate and will probably need one person controlling each model.
- It may end up putting your model of Orca in the shade!
- You may be better trying to team up with a fellow model submariner who can operate , say, a modern nuke with the fin (sail) replaced with a dorsal fin.

A simpler approach may be to tow a submersible body with fin attached.  It would need a ballast tank (pumped water/ bag system?) The ballast tank could be timer controlled.

- Much simpler and cheaper and more under your control.
- You could probably make it yourself. Try towing some lengths of matt black painted weighted plastic pipe (drain pipe) and see how it looks. If it looks OK put a ballast tank in it.
- It is one sub you will never lose! (It is on a tow)
- Occasional, surprising views of a dorsal fin may be more in keeping with the tension and excitement of the film.

If you have seen some of Pauls B's amazing special submersibles (his diving duck and the amazing sinking freighter) you will see what can be done with simple ballast tanks.) He will probably be going to Norwich.

Keep in touch!

David

How about a pop bottle with a styrene fin glued on? You could vary the depth that it swims at by adding or emptying water to it. A coat of grey/black paint would finish it off nicely.

That's a thought. Or maybe have it dive dynamically (Much simpler - like a Paravane but designed to dive when you have any speed on the "Orca".)

http://en.wikipedia.org/wiki/Paravane_(weapon)

With a bit of skill you could get the shark to emerge by slowing down a bit. Appear in different places by going astern etc.

David

intersting ideas chaps, many thanks.

What I achieved in the past, was a cheapo rc shark fro tesco etc, from under the boat hull a length of wire,. attached to string, attached to the shark.

Weighted the shark with a keep effect, so only dorsal was evident, and close inspection was top of body. Using rc helicopter flybar paddles, angled, when the boat was running, up comes the fin, when boat stops shark sinks (to a pre determined height). The wire stopped the shark head butting the boat every time it stops and getting string fouling prop!

It didnt really hit the mark for me, whilst the boat is essentially a "toy" towing a plastic shark made it worse, if you know what I mean.

I like the idea of a controlled ballast tank David, if you could enlarge on this idea, I still like the idea of rc controlled though, I dont know why, maybe its the challenge! bit like trying to get black smoke out of the smoke generator I have on board, the holy grail!

Will post some pics when I work out how to do it, that might help with what I want,
thanks

Paul

Just for you, Paul...

Omg who is that man i want to be his friend soooi bad!

That looks like a flying shark or should i say it is an air shark.
Might destroy the effect you are going for, but it would catch the attention of the crowds! LOL

Love the flying shark, Salmon! (At least all we get over here are midges!)

Sounds like you have gone a long way already with the towed shark idea, Paul. Trouble is anything better will be a challenge and the price and complexity will "ramp up" accordingly.

Also building on the "You're gonna need a bigger boat!" quote. You may find that you need a bigger "Orca" to get the scale right (A small shark will be very difficult to kit out with all the gubbins needed for an autonomous model.)

David

The boat is approx 40" long. It is painted using paint chips supplied by Universal Studios, it has a bespoke sound unit, an mp3 board which has 18 triggers operated from  the transmitter, which has an sd card containing 18 various tracks, dialogue, music etc from the Jaws film. Onboard amp with stereo speakers, all tracks run with an overlayed engine sound, so it sounds great. It has a smoke generator, and 3 scale figures for Qunit, Brodie and Hooper (bet that takes you all back!)

some pics, so you now know why I am being so flippin fussy! The dorsal and tail fins will be the only visible thing, what is below the water does not really matter, I keep thinking the MMB sub is the answer, any comments about this submarine appreciated please!

That is a lovely model. I can see the problem more clearly now. You need a shark model to be in the same league as the model.

What sort of length are you thinking for the shark? About 40"?

David

Morning Paul (Red 181?) wrote:

Hi Rich, are you the same Rich who tried to help on "another forum" some time ago?, if so yes its me, still trying to sort this. I have been let down by a number of empty promises unfortunately, A friend pointed me on to this forum which is a very interesting place to be! maybe subs are my future as sailing boats is a tad boring!

Ill obviously pay for the hull, then maybe I can do a build log on here with a lot of help from members, what does it need, remembering you are talking to an absolute novice with sub technology so make it simple please.

David, underwater length isnt that important really, but ideally 3 foot max, 2 foot would be ideal, its only the fins that will be seen at water level

(strange that half of the pics have disappeared!)

pm sent rich

Fear not, Paul... I haven't forgotten, I've had a couple of bad days.

Hi Paul,

You're next...your parcel will be posted tomorrow for you. Sorry for the delay, I haven't been too good.

Rich

hi rich, sorry to hear you are off colour, i have just stolen some of my sons internet time,pm me your paypal as soon as i am back home ill send some dosh, cheers Paul

Did you receive the parcel, Paul?