More Production Photos from The Cave
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The current 1/72 torpedo manufacturing technique (hollow, cast resin weapon) is too labor intensive. I've got to come up with a better production method. An old idea, but one that seldom came with success -- owing to the high gas leakage rate -- is to cap a length of K&S aluminum tube with a resin warhead and afterbody. Trouble with this method of construction is that the relatively high pressure of the propellant gas (typically 70 psi at room temperature), coupled with the wide thermal expansion rates between aluminum and cast polyurethane resin, stressed the aluminum-resin union to the point where most adhesive would fail and the charge of gas within the weapon would leak away.
I conducted a series of tests involving a very tight interference fit between torpedo parts, use of RTV adhesive, and a radial crimp to not only effect a strong union between these parts, but to also assure a gas tight union, even during the chilling operation employed to get the maximum amount of propellant into the weapon during the charging operation.
Here I've made a series of afterbody and warhead blanks to test -- in mass -- the gas tight integrity of these new type gas propelled, 1/72 weapons. I'm also going to study the effectiveness of different stabilizer off-sets to find which one delivers the most stability to the weapon during its run through the water.
Who is John Galt? -
Another crazy idea!
See attached sketch. Reduction in production machining.
1) Cast the gas chamber with materials that stays with the torpedo. Make a chamber and exhaust nozzle assembly from a straw
with end caps of plastic. The nozzle tube is glued into this and placed in the mold.
2) Pour the resin in one shot mold around the chamber tube assemble. No glueing in plugs and turning to shape.
3) For the gas nozzle fill the tube partially with RTV silicone (if compatible with propllent) then drill the nozzle area with a drill bit.
4) cut a hypodermic neele to length and insert through RTV making a precision size orifice.
Scott T
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Another crazy idea!
See attached sketch. Reduction in production machining.
1) Cast the gas chamber with materials that stays with the torpedo. Make a chamber and exhaust nozzle assembly from a straw
with end caps of plastic. The nozzle tube is glued into this and placed in the mold.
2) Pour the resin in one shot mold around the chamber tube assemble. No glueing in plugs and turning to shape.
3) For the gas nozzle fill the tube partially with RTV silicone (if compatible with propllent) then drill the nozzle area with a drill bit.
4) cut a hypodermic neele to length and insert through RTV making a precision size orifice.
Scott T
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Trouble is machining the resin body to diameter and getting rid of the flange lines -- requires spinning on the lathe followed by putty and primer work. This is pretty much how I manufacture the weapons up to this point. See pictures below:
Way, way too labor intensive. Best just to make the main-body the aluminum tube and be done with the spinning operations.
MWho is John Galt?Comment
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OK. Warhead and afterbody masters done -- check; rubber tools done -- check; cast up and assemble four different type (vary by stabilizing fin off-set) weapons -- check; leak check new weapons -- check.
Fine. Tomorrow Ellie and I go to the Lynnhaven Dive Center pool to find which type weapons runs the best in the pool.
Film at Eleven!
Who is John Galt?Comment
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Hate to throw a spanner in the works, but how hard would it be David to manufacture a longer version of the current 1/72 scale torpedo?
In my experience, I'd love to have a longer running torpedo. That would need simply more fuel. Sure it won't be scale, but those who use this will tell you these torpedoes don't typically get mounted on the display stand for rivet counters to question. Mine have two states, stored in a box, or in use. When in use - their hard buggers to see too. A longer version would need a longer launch tube, but would not need a re-tooled (larger diameter) launch mechanism.
JLast edited by Slats; 11-25-2013, 06:52 PM.John Slater
Sydney Australia
You would not steal a wallet so don't steal people's livelihood.
Think of that before your buy "cheap" pirated goods or download others work protected by copyright. Theft is theft.
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Good news, John:
Just got back from the diver's training pool where Ellie and I did some testing of the 'new' 1/72 weapon. The increased volume within the weapon over the old resin design has resulted in a marked increase in range -- about sixty-feet now. However, I found that I need to tighten up the nozzle throat diameter from its current .014" to .009" as the weapon is too fast and will fly into the air on occasion. Going back to the pool tomorrow with new nozzles and we'll see what kind of range that gives us.
Increasing the weapon length, means a launcher of comparable length.
MWho is John Galt?Comment
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Good news, John:
Just got back from the diver's training pool where Ellie and I did some testing of the 'new' 1/72 weapon. The increased volume within the weapon over the old resin design has resulted in a marked increase in range -- about sixty-feet now. However, I found that I need to tighten up the nozzle throat diameter from its current .014" to .009" as the weapon is too fast and will fly into the air on occasion. Going back to the pool tomorrow with new nozzles and we'll see what kind of range that gives us.
Increasing the weapon length, means a launcher of comparable length.
M
You wonder why your order isn't ready? It's because folks like you dangle carrots like this in front of HWSNBN and off he goes, regardless of order priority, so don't come whining to me because your stuff isn't in the mail!Stop messing about - just get a Sub-driver!Comment
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David - he does has a point. Its been a long wait. Can you please finalise the order ASAP.
Thanks guys.
JohnJohn Slater
Sydney Australia
You would not steal a wallet so don't steal people's livelihood.
Think of that before your buy "cheap" pirated goods or download others work protected by copyright. Theft is theft.
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