1:72 Torpedo

[daveee]

I am trying to make torpedoes for the Gato sub. I haven't been able to find anything on this site that addresses such a small torpedo.
In trying to build a 5/16" OD torpedo using .014" thin wall aluminum tube, it still won't float once I install any kind of filler valve in the front. I am beginning to truly appreciate the problem solving that you guys must go through!
What is "Propel" exactly?
Any help would be appreciated.
Thanks
Dave E

[tmsmalley]

Propel is the trade name

Propel is the trade name of a product from Badger Corporation used as airbrush propellant. Many sub modelers use it to blow ballast tanks by releasing it with various types of valves and some use it to power torpedoes. It contains Butane and is listed on the material safety sheet as highly explosive and a health hazard- see http://pages.slc.edu/~aschultz/chemi...L%20BADGER.pdf



Many of us have switched to Super Dustrer from MG Chemicals. It is nowhere near as hazardous as Propel.

See

http://www.mgchemicals.com/msds/english/aerosol/402a-aerosol.pdf

[daveee]

1:72 Torpedo

Thanks Tim
Does Super Duster have the same valve / threads as the Propel?
Where does one find suitable attachments to the can such as an on-off valve to hose barb or a solenoid valve?
Will the torpedo gain much weight when charged with air?

In thinking about some kind of lighter weight filler valve for the torpedo, I was wondering about the rubber air valves in volley balls, soccer balls etc. If I could source such a valve, machine and glue it into the 5/16" tube, it may not weigh too much? Any coments?

For now I am looking into making the shrader valve receiver in lexan. It still may weigh too much. Maybe a longer torpedo?
Dave

[KevinMC]

Hi Dave,

One solution to the

Hi Dave,

One solution to the valve weighing too much is simply don't include it on the torpedo. Consider leaving the valve on the boat and filling the torpedo through the nozzle on its aft end. This is certainly not my idea, but it is how I'm going to realize torpedos for my 1/96 scale OSCAR II.

I've looked into using SuperDuster myself, and I can tell you that it's available two different cans: one with a crimped top and one with a threaded top that will mate with the standard Propel fittings. Just check what you're buying carefully!

[PaulC]

while it becomes more difficult

while it becomes more difficult in the smaller scales, if you want to use a Schrader valve in the torpedo make the removeable warhead out of, or fill it with, bouyant material to overcome the weight. Mike Dory and Gene Berger to name a few have had success with this in 1/32 scale in the past.

[daveee]

1:72 Torpedo

Thanks Kevin
I like your great idea, but now my imagination has gone wild with a whole new set of questions.
In order to charge the torpedo while in the sub, there would have to be a hollow tube inserted in the back, attached to a flexible hose attached to a filler valve. The tube would be pulled out via a servo. Because the tube hole is much too large as an orifice, the torpedo would have to have the .025" jet hole ahead of the larger tube hole???
Also is the torpedo likely to stay in place (Once charged) without some sort of failsafe?
Do I have it right?
Any suggestions as to the orifice size as a starting point? .025"?

I apologies if these questions seem stupid.
Thanks
Dave

[oracle_9]

Uhm, I am just curious

Uhm, I am just curious about one thing about these Badger Propel and Super Duster, I see they are safe to the ozone, but they have health warnings on them (or no?).
Does it contaminate the water? Wouldnt that be not good?

Why not just use a pager motor, o-ring, singe cell battery, plastic test- tube.

[daveee]

1:72 Torpedo

More questions on torpedoes:
Is the center of gravity really important and if so, where should it be? If it isn't aft of center I would assume the torpedo would run into the deep.
How high in the water should the torpedo float staticly?
Is it a good idea to install the tail fins in a twist so the torpedo spinns?
Is super glue (CA) waterproof?
Thanks
Dave

[tmsmalley]

Oracle - no health or

Oracle - no health or toxicity issues with Super Duster - read the link for more info. I'd encourage you to built a 1/72 torpedo with a pager motor and report back to us on your project.

Davee - You need to buy Super Duster REFILLS - they have the standard thread that fits a Propel adapter as sold by Mike's Subworks.

You want the torpedo to float after the run. A schrader valve would add too much weight to allow the fish to stay afloat. I suspect a pager motor and batteries would have the same problem, but I'd love somebody to prove me wrong.



~ From my old RC-Submarines.com ~

In gas-operated ballast systems (commonly called "Propel" systems) on RC submarines, some sort of compressed gas is used to expell the water from the ballast tanks.

There are several products out there that work, such as Badger brand Propel. I have had good luck using Super Duster 134 as suggested by Mike Dory. It's contents appear to be much safer than some of the other products, having no flammable or toxic components (ie. butane) that Propel has.

According to the Material Safety Data Sheet for Super Duster, the main danger for Super Duster seems to be frostbite. This can be a BIG deal, especially if it happens to your eyes, so don't be an idiot and BE CAREFUL using any of this sort of item.

As the old saying goes - "Nothing is foolproof in the hands of a fool."

By the way, I hang my Super Duster with SubTech adapter on the end of my toolbox using a fire extinguisher bracket I bought at Menard's (hardware/lumber superstore) for about $6. Thanks to RC sub genius, Skip Asay for this neat idea!

Get the latest Material Safety Data Sheet for Super Duster 134 refills at]http://www.mgchemicals.com/msds/[/url]

In the past, I have purchased my Super Duster 134 Refills from Circuit Specialists in Mesa Arizona. Super Duster- 10 oz. aerosol, Super Duster for use with 402T (402AR) http://www.circuitspecialists.com/prod.itml/icOid/1651

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[bryan]

Thanks Tim-

Its like you guys read my mind- Not quite there yet - but it WAS on my mind to so some research on the compressed air for my build. Really appreciate all the information!

Thanks-


-Bryan

[tmsmalley]

A site devoted to electric

A site devoted to electric torpedoes -

http://www.pt-boat.com/torpedo/torpedo.html

[tmsmalley]

Torpedoes and missiles

And here is another page from www.RC-Submarines.com with torpedo and missile information.

http://www.rc-submarines.com/id47.htm

[boss subfixer]

Here is a link to

Here is a link to Frank Ricuccis website. Maybe you can get some ideas.

http://www.modelbrass.com/torpedoes/torpedoes.htm

[paul von braun]

Oooh! Speaking of which, is

Oooh! Speaking of which, is Frank Riccuci in the country, or is he abroad? As I remember, I was very interested in his offering - but never got a reply to any e-mails. Not exactly enticing me to part with money but there you go, I suppose.
Frank, if you are reading this, I WOULD LIKE TO GIVE YOU SOME MONEY IN EXCHANGE FOR A 4 TUBE 1/32 SYSTEM TO GO IN MY OTW TYPE VII.

Paul.

[tmsmalley]

Frank Ricucci's Torpedoes

I bought one of Frank's two-tube torpedo systems for my as yet uncompleted 1/48th Gato. He does one heck of a job on these sets. It seems to me he takes a winter vacation so he might not be around the shop, but he will get back to you I'm sure!