1/48 G7 Torpedos

[Monahan Steam Models]

The quest to build the perfect running scale torpedo is hard. After months of screwing around with building, testing new parts, more design work then more testing. And even more testing. Followed by searching for components, then waiting for them to show up only to have gotten past the need for those parts because of serious changes in design. I have to say I’ve gone bat crap crazy perfecting these damn things but I’m closer then ever and pretty much there but now just want to say screw it I’m close enough and I am seriously over it.

[Monahan Steam Models]

Thanks BG, I’m seeing all 6 pages. It looks like David’s post are the ones that are no longer included from what I can see on my end. Bummer, I really respected his input

[Bob Gato]

Hey, nick...what I see at my end is that your post #78 is on page 6 of the thread-In the lower right of your post's window is a page selector (its says previous) ...if you either click on a page in the box or just type in the page you want-it all is still there(you are only seeing one page of 6 total)-BG

[Monahan Steam Models]

From what I’m seeing on this topic some previous posts are no longer showing up. Maybe a glitch in the forum software or were they removed by the the original poster? Weird.

[Monahan Steam Models]

Sorry for the lack of updates on the development. Work has been crazy lately and it has been difficult getting the raw materials that I have ordered weeks ago delivered. Here’s a couple pictures of the newly made tail sections with some finer details added.

Machined a bunch of new miniature mechanical parts for the latest version of the counter rotating prop internal main chassis. Hoping to get some Testing along with some pictures and video soon once I get the chance. Newest design will be testing a new motor, an updated counter rotating transmission with the new detailed tail cone, along with accurate scale 2 blade props and a smaller LiPo battery

[Monahan Steam Models]

Some more details added to the tail section. Still more to add. The width of the fins had to be fudged a bit to be wider than scale since this is a not a static display model. Scale would have put the fin width around .003-.004”

[Monahan Steam Models]

Starting the process of adding some of the finer details to the G7E Torpedo parts. Here’s the current tail section CAD model with the beginning details being added now that the mechanical functioning part of the project is almost complete. Rudders, planes, hatches and other details will be added soon

[Monahan Steam Models]

Currently waiting for new bits and pieces to arrive for the next rounds of torpedo designs and testing. In the meanwhile here’s a video of a marine steam engine I built from scratch a few months ago being test run on compressed air before being sent out to it new home. Every single part on it is machined and made from scratch. I used to manufacture these in my shop along with the boilers and other bit more than a couple decades ago and hundreds of these are around the world today. I stopped making them back in 2010 to focus on design and machine work for the labs and the private sector but they’re still fun to play around with every once and a while.

https://youtu.be/2wnT55L4wkg

[Monahan Steam Models]

Not too insane when you boil it down to the basics. Let’s look at it mechanically for a sec. Can you fit two 4mm motors side by side in a 10mm space. Yes you can. Can you provide the proper distance from each motor shaft centerline to prop shaft centerline in a 10mm circle foot print. Yes I think so with the right gearing. It’s much easier to have control with two variables in real time then only one where you have to get the mechanical dynamics balanced out just right. Im taping this out on a smart phone which has micro accelerometers sensing the exact position of the phone. Think about that for a moment, fairly small light weight components right? Micro RC airplanes, helicopters and drones with gyro stabilization hardware use similar micro sized chips. I think it’s achievable with some r&d work.

[coryhenry]

To make design matters even more challenging to navigate, I’ve been playing around with the idea of running twin 4mm counter rotating motors each driving their own shaft and using a small custom designed pc and some code to sense torp body roll and compensate with adjusted individual motor Rpm’s control to correct body roll. Wouldn’t take too much to do. I would think you could almost steer the thing by manipulating the prop thrust

That is insane, anxiously waiting for this!

[Monahan Steam Models]

It was weird, they shipped the 5F caps by air today but would not ship the 25F caps by air. Oh well, the design is starting to split paths. I have parts coming to optimize the LiPo version as well as the super cap version. Some latching and non latching double throw reed switches are on their way too. Mainly for the super cap design.

In all of this, I still need to focus now on designing optimized scale counter rotating prop designs. To date I’ve been using modified props off a hoard of 1/125 type VII revell u-boat kits left over from 20 plus years ago when I converted one of those to RC.

To make design matters even more challenging to navigate, I’ve been playing around with the idea of running twin 4mm counter rotating motors each driving their own shaft and using a small custom designed pc and some code to sense torp body roll and compensate with adjusted individual motor Rpm’s control to correct body roll. Wouldn’t take too much to do. I would think you could almost steer the thing by manipulating the prop thrust

[Bob Gato]

Paleese! Are they kidding! They are just aluminum foil and wax... somebody must have thought they were batteries...
Wow -ii can't wait to see those heavy hitters perform.

[Monahan Steam Models]

Okay that’s cool! Thanks for sharing this! Btw, I ordered a couple more super caps today. There’s a few 3v 5F’s on their way and a few 3.8v 25F‘s!!! Mwahahahaha!

Couldn’t help myself when I saw it! The hot rod builder in me had to do it. That one they called me shortly after I placed the order to say it’s considered restricted and can’t be shipped by air. Has to go ground.

[Bob Gato]

Nick...no need for expensive expandable radios to launch torpedoes. Five would be tough... but four would be easy using an inexpensive 433 MHz garage door/ light rc unit...tiny key fob like transmitter is simply clipped, Velcroed or two side taped to the main transmitter. Four push buttons each control a 10 amp relay.

[Monahan Steam Models]

Manfred, thanks for sharing your experience with torpedoes. I really enjoy seeing your build posts and the progress you’re making on your projects. You’re a great builder!

The design for these torpedoes sounds very similar to yours. For me, this was also mainly due to how the launch tubes will be configured in the type VIIC. I do like the way 1s LiPo performs and during the test runs of each design, being able to get multiple runs from one charge has been helpful.

With the lack of multi channel expandable surface radios available today, I’ve had to compromise on how to go about launching each of the 5 tubes individually using only one available channel. I plan to use one of Kevin McLeod’s launch module for gas solenoids and launch each tube with propellant. I think I’ve come up with a way to get each forward torpedo door to open just before the launch occurs for each tube and then close after. Getting the torpedoes perfected to me seems like the logical first step. Then I can move on to the launcher.

Nick