1/48 G7 Torpedos

[Monahan Steam Models]

I have really enjoyed the progress you have made with these torpedos! I am waiting for the 1:48 Arkmodel Type VII kit to be delivered by Mr. Martin in about a month and would love to eventually rig it for firing such torpedos. My thought is that retrieving them should be good sport too? Perhaps if they were ballasted with one ore more small magnets... and mounting reverse polarity magnets under the exposed bulges of the ballast tanks on the sub... I could sail around the pond with deck awash, snag the torpedo(s) and bring them back?

I like the concept that you have proposed. If there was a strong magnet in the nose cone of the torpedo, then you may only need to have a strip of steel along your subs hull to get them to stick to the side as you navigate past them.

[Chuck Harmon]

I have really enjoyed the progress you have made with these torpedos! I am waiting for the 1:48 Arkmodel Type VII kit to be delivered by Mr. Martin in about a month and would love to eventually rig it for firing such torpedos. My thought is that retrieving them should be good sport too? Perhaps if they were ballasted with one ore more small magnets... and mounting reverse polarity magnets under the exposed bulges of the ballast tanks on the sub... I could sail around the pond with deck awash, snag the torpedo(s) and bring them back?

[Bob Gato]

Now that's a backstory!

[Monahan Steam Models]

Ha! Yeah after that test I spent the rest of the day launching pens at the mrs. She was not impressed to say the least... When I do contract engineering work, I do it under Monahan engineering. The Monahan steam models handle dates back to when I had a company under that name producing miniature live steam engines for Rc model boats. Started and operated a few companies before and after that. Those engines and steam plants are on every continent which is kinda surreal. Got to meet a lot of awesome folks from around the world during that time. Every day was like Christmas at that job. I’d design a part, wrote the code for it to be made on the multi axis cnc machines and then test it that same day.

In the evenings or butt crack of dawn, got to chat with folks from all around the world and help them on their projects. Lots of really awesome people from all sorts of backgrounds. I always joked, I used the most advanced technology to make antiquated technology. I didn’t care. I was having fun and could make you anything you could dream of. Those were the days. Now I just want to tinker in the shop. Hell, I planted a lawn just so I could be that guy that says get off my lawn but that hasn’t happened yet. Till then I’ll mess with designing things that I think are neat and try to share that experience in hopes to help others.

[Bob Gato]

[QUOTE=Monahan Steam Models;
I decided to load the tube with a torpedo to see how it worked compared to earlier tests, launching the tubes with the syringe. Wow! I should’ve probably gave that torpedo more room to travel cause now it’s in the repair shop for major repairs....
Nick [/QUOTE]

LOL-without water to dampen the force-I'll bet it will travel! I used to shoot cut off pencils eraser end out for dry tests. You need to change that name to "Monahan Engineering" Great Info here. Real Progress also.

[Monahan Steam Models]

Did a little bit of experimenting in the shop today. Was able to make a quick test prototype holder for the cartridge style poppet valve. The outlet for it is 3D printed. It slides over the 13/32” OD K&S brass tubing that the poppet valve inserts into. The 3D printed outlet has a very tight almost press fit over the brass tubing. The design keeps the poppet valve cartridge from being pushed out of its tube from the pressure it is holding back. Works get with zero leaks tested at 85psi.

Also made a small air reservoir tank to hold the volume of air needed to push the floating piston inside the torpedo tube to just short of the tube’s muzzle. One end of the tank connects to the poppet valve holder. The other end of the tank uses a one way ball style check valve. Charging the tank was tested two ways. First was by the shop air compressor that was set at 85psi and the other method was using a 100ml Syringe.

I chose to use a check valve instead of a Shradder valve because I wanted to see how well it would work for charging the tank by simply slipping a hose over a the full tube that is connected to the check valve on the tank. The upside to this is the connection is quick and takes up very little room and the fill tube connection can be placed anywhere in the model. The downside to using an unsprung or floating ball style check valve is the valve will have equaled pressure on both sides of it and won’t seal until pressure on the inlet side of the valve is suddenly released cause the valve to slam shut.

Now that the a testing prototype for the poppet valve holder and reserve tank were finished I could move on to connecting them to a launch tube to see if would send the floating piston inside the launch tube far enough, and quick enough with out launching the piston out the muzzle.

Success!!! Charging the Reservoir tank with either the shop compressor or the syringe yielded the same performance results. Once the poppet valve was pressed the floating piston would shot down the tube and stop just short of the muzzle.

Charging the system with the syringe is simple. Draw the syringe back to 100ml. Connect the tubing from the syringe to the hard line coming from the check valve by sliding it on about 3/16” of an inch. Squeeze the syringe like hell until the clear tube blows off the end of the hardline and Voilą that tube’s system is ready.

I decided to load the tube with a torpedo to see how it worked compared to earlier tests, launching the tubes with the syringe. Wow! I should’ve probably gave that torpedo more room to travel cause now it’s in the repair shop for major repairs....




It was a good day of testing and the theory of this part of the design yielded positive results. If I decide to pursue this design, I now have a good baseline to work from.

Nick

[george]

George,

I found them on flea bay. Here’s a link:

https://www.ebay.com/itm/Lee-Company...e-9f9128be6465

Thank You very much for the info/help.
George

[Monahan Steam Models]

Could you tell me from whom did you order them from? What was the price? Any company contact information you can share also.
Thanks

George,

I found them on flea bay. Here’s a link:

https://www.ebay.com/itm/Lee-Company-Miniature-Solenoid-LHDA0521211H-3-Port-Face-Valve-Port-5V-DC/264214508125?pageci=02ea8b77-5558-40a9-a7ee-9f9128be6465

[george]

That’s awesome! Thank you so much sir! I just sent you an email. Btw, the solenoid valves showed up earlier than expected. Arrived this afternoon. Wow they are tiny when you see them in person!

Could you tell me from whom did you order them from? What was the price? Any company contact information you can share also.
Thanks

[Monahan Steam Models]

Neat little cartridge type poppet valve that showed up today made by Clippard. Fits and seals nicely inside 13/32” K&S brass tubing. At this stage of the launch tube design, this is what I’m thinking of using to send compressed air to each tube once the pneumatic piston opens that tube’s door.

The pie in the sky idea here is to somewhat isolate each stage of the launch sequence for each tube. I’m trying to get as Rube Goldberg as I can here.

The launch tubes have a floating piston inside of them that the tail of the torpedo locks into via a slight interference fit on the tail fins. The velocity at which the piston reaches the end of its travel in the tube allows the torpedo to continue forward while the piston stops in the tube due to the force on it switching from pressure pushing to vacuum stopping. I know from tests it take 20ml of low pressure air to push the torpedo out of the tube without sending the floating piston Inside the tube with it due to this effect demonstrated in earlier posted videos.

My ideal situation would be to isolate the stored air for the piston tube launch circuit with a poppet valve. This way I can pre charge each tube with a measured amount of low pressure compressed air that will be released to the tube once the poppet valve is triggered.

If I can accomplish this the high pressure side of the launch mechanism will limited to just the pneumatic pistons and solenoids for opening each tube’s doors before triggering the poppet valve. Yes this could be done a lot simpler with springs in the tubes and linear solenoids to open the doors but.....

[Monahan Steam Models]

George, they are 3 port

[Monahan Steam Models]

That’s awesome! Thank you so much sir! I just sent you an email. Btw, the solenoid valves showed up earlier than expected. Arrived this afternoon. Wow they are tiny when you see them in person!

[He Who Shall Not Be Named]

I'll check the sheds -- they're somewhere I hope. Will get back to you on this.

David

Success! Found an old manifold blank -- good for many solenoids closely mounted together, as well as a five solenoid manifold complete with nipples and mounting hardware.

I've got pounds of torpedo and launcher stuff rotting in the sheds -- it all will wind up in a landfill eventually. Anything else I can slip into the box for you?



E-mail me your mailing address and I'll get them off to you tomorrow. dmeriman@aol.com

Love your work, sir.

David

[george]

Could you Sir; HWSNBN tell me where those solenoids 2 port or 3 port versions you used?
Could I also get 3 manifolds that hold 2 solenoids each? Let me know the cost.
Please/ Thank You
George

[Monahan Steam Models]

Thank you Sir!