3D Printing Submariens and Sub Components

[Sinksalot]

RCJetDude, for your Futaba T9CAP look around for Futaba module FP-TJ-FM as they are already 75mhz. Also look around for Futaba Synthesized module PK-FSM. It will let you use any 75mhz freq on your T9CAP, please note the PK-FSM will only work with single conversion receivers. I was able to buy a few 8 channel 75 mhz receivers off a hobby shop in china. They are tiny little things, 33mm by 22mm by 12mm. They work great on my Futaba Robbe F-16, FC-28, T7CAP, T8UAF, T9CAP Super and Vex. All at 75mhz. Yea I know I got to many radios lol. I also sent a few receivers and TX modules to Radio South a few months ago, he is pretty quick. Mostly FP-TK-FM modules with FP-R148DF and FP-R148DP receivers for better retuning to 75mhz. My current projects are a new Engel U177 1/45 scale sub. I also bought the optional upgrade kit with the late war decking and conning tower from modellbau-wikinger. To get that sub shipped to the US in its close to 7 foot long box was a very tearful moment for my bank account. I also have three 3D printed subs I am working in Fusion 360. it just takes time which I just never have, so it slow going.

other David

PS, Been reading stuff in this forum for a long time. Just never open my mouth before. That maybe a good thing or a bad thing

[rwtdiver]

[QUOTE=He Who Shall Not Be Named;n137375]

Well crap! My tub isn't long enough to float my boat so I can trim it. Now I have more incentive to get the pool running again.[/QUOTE

LOL. We all have our Crosses to bear (err …. deer). Clean that pool and get back into the game. Man! I've heard some lame excuses before, but … Damn!





David
The Horrible

David is right!! Use the pool!!

[He Who Shall Not Be Named]

[QUOTE=RCJetDude;n137374]Well crap! My tub isn't long enough to float my boat so I can trim it. Now I have more incentive to get the pool running again.[/QUOTE

LOL. We all have our Crosses to bear (err …. deer). Clean that pool and get back into the game. Man! I've heard some lame excuses before, but … Damn!





David
The Horrible

[SubDude]

Well crap! My tub isn't long enough to float my boat so I can trim it. Now I have more incentive to get the pool running again.

[He Who Shall Not Be Named]

You distilled it most succinctly, Rob. Trial and Error as to amounts and placement of weight and buoyant foam.

Bottom line: Increase the vertical distance between c.g. and c.b. and the vessel becomes more statically stable about the roll and pitch axis.

David

[rwtdiver]

OMG!! David!

I think I VERY BASICALY understand what you just wrote above!! Between the two (weights and Foam) you add a little here and take away a little there. Trail and error seems to be quite profound here for me!

I really have so much more to learn and comprehend about this hobby! Thank you very much for taking your time to explain the c.b. principal! Waite till I show this to some of my old RC flying friends!

Rob

"Firemen can stand the heat"

[He Who Shall Not Be Named]

Hi David!

I was wondering if the blue foam addition high in the hull might be the answer! My question to you is what is the c.b.? I understand the c.g. and I am just about on with the weights that I added to the center of the keel. If my thinking is correct, I would add the blue foam in equal amounts in the upper hull over the c.g.!?



Thanks for your advice and help David!

Rob

"Firemen can stand the heat"

By, 'equal amounts', you mean equal amount of force (a pound of feathers takes up a lot more volume than a pound of lead).

The following applies to 'wet-hull' type model submarines, but applies for the most part to dry-hulls as well though with that type you can only change the weights position as the displacement is fixed by design.

c.b.= center of buoyancy. The c.b. is the nexus of all the buoyant forces the vessel exerts as a consequence of its immersion in the fluid -- in this case a liquid. The force of buoyancy is a consequence of the weight of the water displaced.

Buoyancy is a force whose vector points up. A submarine (unless its sitting on the bottom) changes its weight and displacement to maintain equality between the two forces, gravity and buoyancy. The magnitude of the gravity and buoyant forces will change, but they will change equally. That's how you achieve either surfaced trim, or submerged trim.

Any vessel (regardless of the fluid it resides within) becomes statically stable when the c.b. is above and in line with the c.g. The greater the distance (moment arm) between these two points of force, the more statically stable becomes the vessel. In a submarine you increase that moment arm by lowering the c.g. (more fixed weight down low), and raising the c.b. (more buoyant foam up heigh, but no higher than the waterline). The trick is to match the two forces, i.e. produce one pound of weight, and counter it with one pound of buoyant force. Equal amounts of force. The net trim has not changed, but the vessel is much more stable about the roll and (to a much lesser extent) pitch axis. Most submarines can not dynamically produce rolling force and rely exclusively on static stability to maintain an upright condition -- that's why they are subject to the unwanted effects of propeller torque, sail-roll, and boundary-layer shearing (snap-roll).

More fixed weight down low. More buoyant foam up high.

https://youtu.be/2O8gTIr4lys

David

[rwtdiver]

I did have an issue with a slight leak through the water proof on/off switch!



I have reprinted another end cap, and designed and printed a containment box for the new switch. I has a threaded top with a rubber seal. This should solve the leak problem..



Rob

Firemen can stand the heat"

[rwtdiver]

Yes it is my first RC sub. I have wanted one for years. A Nautilus is on my bucket list. I spent a lot of time trying to make sure the hull seam was as minimal as possible. I used the Evercoat Rage recommended by Bob in one of his videos and it worked out great. Printed in PLA+, sanded and primered 3X. The new MSD looks like it should work exceptionally well in the boat. I have learned a ton on this build. I know 3D printing has its limitations but it has allowed me the opportunity to get started. I am a long time foam EDF flyer and am well versed on the effects of sun on a model so I am no stranger to it. My scum line is really too prominent so I may try to re-do it. Less is more but it was my first ever attempt. I have a line on the mold for a big Typhoon which may be my first fiberglass hull project. I hope to lay it up soon. Was it difficult to trim your boat? Did you use foam in the upper hull?

Hi Steve,

Hope it was OK to use your name!? I got it off your profile! My boat did trim out somewhat, but it still needs some help with ballast set up. The torque from the screw when I throttle up to high causes the boat to torque roll. As suggested by David Merriman, I need to add some foam in the upper hull to help correct this issue! It does make sense to me! Still got a lot to learn!!

Rob

"Firemen can stand the heat"

[rwtdiver]

Raise the c.b. higher over the c.g. More fixed ballast low, more buoyant foam up high. That will reduce the torque roll.

David

Hi David!

I was wondering if the blue foam addition high in the hull might be the answer! My question to you is what is the c.b.? I understand the c.g. and I am just about on with the weights that I added to the center of the keel. If my thinking is correct, I would add the blue foam in equal amounts in the upper hull over the c.g.!?



Thanks for your advice and help David!

Rob

"Firemen can stand the heat"

[SubDude]

RCJetDude!

That is one nice looking Redoutable! You are to be commended on a beautiful job! Love your paint scheme also..

I see you also went with the new MSD for full capabilities. Is this your first boat? If mine comes out 1/2 as nice as yours I will be happy!!!

Again! Very nice job!!!

Rob

"Firemen can stand the heat"

Yes it is my first RC sub. I have wanted one for years. A Nautilus is on my bucket list. I spent a lot of time trying to make sure the hull seam was as minimal as possible. I used the Evercoat Rage recommended by Bob in one of his videos and it worked out great. Printed in PLA+, sanded and primered 3X. The new MSD looks like it should work exceptionally well in the boat. I have learned a ton on this build. I know 3D printing has its limitations but it has allowed me the opportunity to get started. I am a long time foam EDF flyer and am well versed on the effects of sun on a model so I am no stranger to it. My scum line is really too prominent so I may try to re-do it. Less is more but it was my first ever attempt. I have a line on the mold for a big Typhoon which may be my first fiberglass hull project. I hope to lay it up soon. Was it difficult to trim your boat? Did you use foam in the upper hull?

[He Who Shall Not Be Named]

Today I added the weight to the keel of the Redoutable, and put her to the water! The deck was just awash and she looked pretty darn good! My wife took a video shot, and as soon as I can get it together I will post it.


The only issue I had, was the prop was a little to much at full speed! It really torqued over! So with a little management on the throttle it ran straight and true. The rudder response was not very good even though I did enlarge it. Other than that, I think the boat is now ready for the finish room!!

I will do my best to get the video up ASAP!

Rob

"Firemen can stand the heat"

Raise the c.b. higher over the c.g. More fixed ballast low, more buoyant foam up high. That will reduce the torque roll.

David

[rwtdiver]

RCJetDude!

That is one nice looking Redoutable! You are to be commended on a beautiful job! Love your paint scheme also..

I see you also went with the new MSD for full capabilities. Is this your first boat? If mine comes out 1/2 as nice as yours I will be happy!!!

Again! Very nice job!!!

Rob

"Firemen can stand the heat"

[SubDude]

Nice work sir! My Redoutable is very close to being done. Had a bit of a snag with the AD2 as it did not like to play with the Futaba R149DP PCM receiver I was trying to use. I purchased a few R148DF PPM receivers and one of them allowed me to at least confirm that they will work. Bear in mind I am running a Futaba T9CAP radio that has been re-tuned to 75Mhz (CH 67). Right now the PPM receivers, crystals and Tx module are on their way to Radio South for re-tuning. When I get them back I will be able to button up the WTC and start trimming it. I went ahead and did some weathering and added a scum line. My first ever attempt at such. I tried to follow Bob's video and used a laser level to establish the line which worked great! Meanwhile, the lake I live near where I plan to test it has been closed due to the Coronavirus so I have to wait for it to open back up. No big deal as it is giving me the time to sort out the issue with the pitch controller.

[rwtdiver]

Today I added the weight to the keel of the Redoutable, and put her to the water! The deck was just awash and she looked pretty darn good! My wife took a video shot, and as soon as I can get it together I will post it.


The only issue I had, was the prop was a little to much at full speed! It really torqued over! So with a little management on the throttle it ran straight and true. The rudder response was not very good even though I did enlarge it. Other than that, I think the boat is now ready for the finish room!!

I will do my best to get the video up ASAP!

Rob

"Firemen can stand the heat"