Launch mechanisms?

[Monahan Steam Models]

On the topic of Ronson type fill valves, I’d like to share with those of you who may not be familiar with using these valves a couple quick pieces of information the may be useful.

The thread size they use is M4.5 X 0.5

As I mentioned in earlier posts, these fill valves are commonly used for refillable Butane/propane gas tanks purpose made for steam engine boilers within that wide range of hobbies.

I used to be one of those manufacturers more than a decade ago and produced a wide range of engines, boilers, fuel tanks and other bits for the marine hobby market.

I’ve attached some photos of a commonly designed style of a refill adapter available from a number of model steam engine manufacturers who sell refillable fuel tanks.

These are made to thread onto the disposable fuel canisters for light weight backpacking style camping stoves that use 70/30 mix of butane/propane which are available at most outdoor recreational stores.

I forget off the top of my head the exact Size and thread count used on these canisters, (I would need to dig through my old design archives) but here is the good news. The size and pitch that is used on these canisters is also common across a number of other disposable canister products, including airbrush propellant canisters.

These Ronson type fill valves are especially useful when space and weight requirements within a design do not permit the use of a tire style shradder valve stem.

Hope this information is helpful to some of you out there.

Nick

[Monahan Steam Models]

So far today the bench testing propellant filling operation of the torpedo through the Ronson valve outside of the torpedo tube with the launch piston installed that is sealed around the torpedo’s nozzle has gone well.

The tests loading of the live charged torpedo into the testing rig launch tube has gone smoothly. Each dry test launch out of the testing rig launch tube with a live torpedo has been successful as well.

The piston travel distance down the launch tube (pre figured from the launch tank volume storage) transitions from pressure driven to stopping by the force (pressure) on the piston’s travel switching to vacuum, while the weapon’s mass still wanting to travel forward (Newton Law) worked perfectly to break the seal on the torpedo’s nozzle.

The design concept and design of gas driven torpedoes has been in use and proven to work for decades by many talented builders.

The tests today are designed to explore different charging and launching designs of this type of weapon and to hopefully expose the pros and cons of each.

Nick

[Monahan Steam Models]

love the central storage of gas. Really well designed torpedo. Would like to see what your fish in the pond think of the gas torpedo!

Thanks Tom, I appreciate your input. I’m hoping to do some tests later this week. The big thing I’m curious about is pushing the gas torp out the tube via the piston verses swimming out. What effect will that have on the launch running characteristics? No need for porting the launch tubes? We’ll see...

[trout]

love the central storage of gas. Really well designed torpedo. Would like to see what your fish in the pond think of the gas torpedo!

[Monahan Steam Models]

Fantastic work, sir.

David

Thank you, Sir!

The design still does not beat your production methods for gas weapons! They were in the front of my mind as I was hunched over the lathe turning these parts thinking to myself “damn it, David was right” hahaha, there ya go! I’ll admit it!

Nick

[Monahan Steam Models]

Blast from the past https://www.rc-submarines.net/torpedoes.html

Oh wow, I have not seen Mike Dory’s write up on his torpedoes in years. Good find!

Very very similar to the torpedo I just made. I decided to use O-ring seals for the central pressure vessel’s bulkheads and tie them together with a brass tube acting as both the stand pipe as well as a stay bolt so the ends can’t blow out. The O-ring groove size and seal squeeze takes into account the expansion and contraction under varying temperatures for both the aluminum tube and the brass bulkhead materials.

Nick

[He Who Shall Not Be Named]

Fantastic work, sir.

David

[Monahan Steam Models]

Nice touch nick, as I see it the gas/liquid is retained centrally for CG purposes? Nice being able to charge weapon outside of the boat-BG

Thanks BG, yes sir you are correct about the gas/liquid centrally for CG. Also I’m trying to keep the warheads removable so they can be a separate replaceable item on both the gas and electric versions.

Nick

[Monahan Steam Models]

Here's the finished internal guts for the gas torpedo










Assembled gas torpedo.




Warhead removed showing the gas charge valve. The torpedo can be filled using this valve or it can be filled through the nozzle.



Assembled center section with the warhead and tail cone removed.



Gas torpedo with launch tube piston in place.



Gas torpedo next to the electric counter rotating propeller version.

[redboat219]

Blast from the past https://www.rc-submarines.net/torpedoes.html

[Bob Gato]

Nice touch nick, as I see it the gas/liquid is retained centrally for CG purposes? Nice being able to charge weapon outside of the boat-BG

[Monahan Steam Models]

Looks like the photo didn’t post yesterday. Here it is again

[Monahan Steam Models]

Here’s the basic CAD drawing of the gas torpedo. It uses the same war head resin casting, aluminum center body and resin tail cone as the G7E electric fish but the guts are simpler.

I have a number of Ronson Cigarette lighter type fill valves left over from producing fuel tanks for miniature steam engine systems so I incorporated one into the design as a fill option on the torpedo’s central propellant storage tank.

Torpedo propellant charging occurs outside of the boat’s launch tubes by having the tube’s launch piston secured and sealed over the torpedo’s tail cone and nozzle. The warhead is removed to charge the propellant tank via the Ronson valve.

Once charged, the war head is installed back onto the torpedo assembly and the torpedo assembly with the launch piston is pushed inside the launch tube and seated against the torpedo tubes breach. At this point the safety ball situated at the muzzle end of the launch tube drops into place and restricts the weapon from leaving the tube until commanded to do so via the Tube’s launch sequence.

[Monahan Steam Models]

Small update.

The new higher pressure Lee Company solenoid valves (30psi maximum operating range) and Clippard adjustable pressure regulator arrived awhile ago. These New 5v Lee 30 psi solenoids perform much more consistent with the launch system then the earlier 5v 15psi max operational psi solenoids did which is not a surprise considering the launcher seams to happily function at low minimum pressure of 21psi.

A precision Clippard adjustable output pressure regulator has been added to the Lee solenoid launch valves to provide a constant 22.5 psi to the system no matter the input pressure.

So far these new components have worked flawlessly with 100% repeatability in functionality. The new Lee valves provide integrated ports that easily accept Flexible tubing connections.

Now that this portion of the launch mechanism has been worked out, I can finally move on to the dual weapon type system. (Electric torpedo and gas torpedo)

The only modifications necessary to the current Launcher design that I can see at this point will be adding a safety torpedo launch stop to each tube (this will be thanks too the same design David employed in his launchers with the forward ball lock)

The launch tube pistons will be updated, but will be the same design between electric weapons and gas weapons.

Both weapons will be pre loaded into the standardized launch tubes, live with the safety lock latched until commanded to launch. If the design proves to be successful, no fueling of the gas torpedo will be required after pre loading into the tube.



Nick

[He Who Shall Not Be Named]

The manifold blanks were were cast from Polyurethane in rubber tools. Rods placed into the tools cavity formed the internal channels in the cast manifold blank.