Gwen's Arkmodel 1/48 scale RC Type VIIC build log

Gwenydd · 10-20-22, 02:17 AM

So, for anyone who isn't already familiar with this stuff, this is what the insides of most static diving RC submarines look like. Static, as opposed to Dynamic diving, means that the dive system is capable of allowing the submarine to dive without needing to move forward or backward and pushing itself down using the dive planes. Static systems dive by changing the overall buoyancy of the boat, so static diving systems tend to be more complex than dynamic systems.

This is the WTC or Watertight Cylinder containing all the electronics, batteries, radio gear, motors, servos, etc. to operate the sub. Mine is a 3" diameter tube with an 8" long ballast tank. If you do the math it works out to 56.55 cubic inches of volume or 2.039 pounds of water at 70 degrees. At least until I become proficient at operating the sub safely I will keep it set up to only flood to neutral buoyancy, which means I can operate pretty much normally using the dive planes (along with forward motion) to dive and surface before blowing the tanks. Later I may set it to allow for some negative buoyancy to allow quicker dives and diving in place... we'll see how it goes.

This is the forward section of the WTC which contains forward dive plane and torpedo door servos as well as the radio receiver, battery, a battery and radio signal monitor board, and wireless on/off switch for the sub that uses a key fob to activate.

This is the center section which is the ballast tank. The brass cylinder in the middle is a canister that can be filled with compressed airbrush propellant to emergency blow the tank. The tank vent is a small brass tube on top with a valve which is activated with a servo motor to allow air out of the tank and for the tank to flood. The large opening on the bottom of the tank allows water to enter as well as providing maintenance access. You can see the wiring for main power, servo motor, and engine controls running through an airtight tube that runs all the way through the ballast tank at the top. The airtight tube also allows the pressure inside the forward and aft WTC compartments to equalize.

And this is the aft section of the WTC containing the main drive motor and ESC, aft dive plane servo, rudder servo, two air pumps for blowing the ballast tank, and an electronic auto-leveling board connected to the aft dive planes.

I have already done a bit of setup on the WTC, mostly involving running wires and connecting servos and the subsystem control boards.

And last is a view of tha aft end of the WTC showing the control pushrods and gearbox to drive the twin propellers. The brass filler valve on the hose to the right allows me to fill the emergency ballast blow tank with airbrush propellant. The other two hoses are for the ballast air intake and pressurization testing.

I have been building various types of RC vehicles for many years and this one is the most complex system-wise I have done so far. There's a lot of stuff to set up, program, tweak, and maintain. Much more than an RC airplane or tank.

More to come on this subject as the work progresses...

Gwenydd · 10-20-22, 11:44 PM

I decided today I just wasn't comfortable with the fragility of the railings on the Arkmodel Type VIIC so I am replacing all the plastic railings with soldered brass ones. Also the wintergarten railing wasn't quite shaped right so...here's my start on the wintergarten upper rail replacement. I'm waiting for more brass rod to arrive in the mail before I proceed any further because I'm all out...

Onkel Neal · 10-22-22, 09:09 AM

Oh boy, I have been waiting for this

The Arkmodel is designed fopr RC use, then? On the stern planes and rudders, the small screws are part of the kit out of the boy? What material are the threads the screws screw into? Are they metal or plastic? Or metal axle shafts?

Gwenydd · 10-22-22, 06:34 PM

Quote:

Originally Posted by Onkel Neal

Oh boy, I have been waiting for this

The Arkmodel is designed fopr RC use, then? On the stern planes and rudders, the small screws are part of the kit out of the boy? What material are the threads the screws screw into? Are they metal or plastic? Or metal axle shafts?

Yes, it was specifically designed for RC use. Yes, those small screws on the control surfaces are included in the kit. They screw directly into the end of the control surfaces which are made of ABS plastic, so you have to be very careful when installing or removing them not to strip them out. I am probably going to make a set of metal threaded inserts (or maybe just use nuts) and drill out the holes larger and glue them in place so I have a more durable connection. The shafts for the control surfaces are all steel rods and the mount points on the hull have brass bushings for them to fit through, so they all turn pretty smoothly and without wobble.

ET2SN · 10-22-22, 07:01 PM

Gwen, have you tried using "loc-tite" on metal parts and screws?

Its a little temperamental when compared to the super glues, but its also durable and easy to work with. You can find it in any "automotive" isle and, worst case, at any auto parts store. And, its pretty cheap.

I've had good results using it on 1/118th scale die casts and even on some plastic models.

Gwenydd · 10-22-22, 07:06 PM

Quote:

Originally Posted by ET2SN

Gwen, have you tried using "loc-tite" on metal parts and screws?

Its a little temperamental when compared to the super glues, but its also durable and easy to work with. You can find it in any "automotive" isle and, worst case, at any auto parts store. And, its pretty cheap.

I've had good results using it on 1/118th scale die casts and even on some plastic models.

Sure, I always try to use a thread locker on metal to metal connections like that. But the issue here is that with an RC model it is often necessary to remove the control surfaces to fix something or make adjustments and with a metal to plastic connection the plastic WILL eventually wear out from use. So a metal to metal, ie a small screw and nut, will be much more durable and reliable.

ET2SN · 10-22-22, 07:20 PM

Yeah, there's "loc-tite" then there's what I call "less-than-loc-tite" which has some fillers blended into it so the parts can still be removed.

I think all of us who have a drawer full of alum. and brass tubing for scratch building have a bottle of this stuff somewhere on the shelf.

10-20-22, 02:17 AM	#1
Gwenydd verrückt kaleun Join Date: Nov 2014 Location: Northern Washington Posts: 92 Downloads: 143 Uploads: 2	WTC (Watertight Cylinder) 101 So, for anyone who isn't already familiar with this stuff, this is what the insides of most static diving RC submarines look like. Static, as opposed to Dynamic diving, means that the dive system is capable of allowing the submarine to dive without needing to move forward or backward and pushing itself down using the dive planes. Static systems dive by changing the overall buoyancy of the boat, so static diving systems tend to be more complex than dynamic systems. This is the WTC or Watertight Cylinder containing all the electronics, batteries, radio gear, motors, servos, etc. to operate the sub. Mine is a 3" diameter tube with an 8" long ballast tank. If you do the math it works out to 56.55 cubic inches of volume or 2.039 pounds of water at 70 degrees. At least until I become proficient at operating the sub safely I will keep it set up to only flood to neutral buoyancy, which means I can operate pretty much normally using the dive planes (along with forward motion) to dive and surface before blowing the tanks. Later I may set it to allow for some negative buoyancy to allow quicker dives and diving in place... we'll see how it goes. This is the forward section of the WTC which contains forward dive plane and torpedo door servos as well as the radio receiver, battery, a battery and radio signal monitor board, and wireless on/off switch for the sub that uses a key fob to activate. This is the center section which is the ballast tank. The brass cylinder in the middle is a canister that can be filled with compressed airbrush propellant to emergency blow the tank. The tank vent is a small brass tube on top with a valve which is activated with a servo motor to allow air out of the tank and for the tank to flood. The large opening on the bottom of the tank allows water to enter as well as providing maintenance access. You can see the wiring for main power, servo motor, and engine controls running through an airtight tube that runs all the way through the ballast tank at the top. The airtight tube also allows the pressure inside the forward and aft WTC compartments to equalize. And this is the aft section of the WTC containing the main drive motor and ESC, aft dive plane servo, rudder servo, two air pumps for blowing the ballast tank, and an electronic auto-leveling board connected to the aft dive planes. I have already done a bit of setup on the WTC, mostly involving running wires and connecting servos and the subsystem control boards. And last is a view of tha aft end of the WTC showing the control pushrods and gearbox to drive the twin propellers. The brass filler valve on the hose to the right allows me to fill the emergency ballast blow tank with airbrush propellant. The other two hoses are for the ballast air intake and pressurization testing. I have been building various types of RC vehicles for many years and this one is the most complex system-wise I have done so far. There's a lot of stuff to set up, program, tweak, and maintain. Much more than an RC airplane or tank. More to come on this subject as the work progresses... __________________ Gwen Last edited by Gwenydd; 10-23-22 at 12:38 PM.

10-20-22, 11:44 PM	#2
Gwenydd verrückt kaleun Join Date: Nov 2014 Location: Northern Washington Posts: 92 Downloads: 143 Uploads: 2	I decided today I just wasn't comfortable with the fragility of the railings on the Arkmodel Type VIIC so I am replacing all the plastic railings with soldered brass ones. Also the wintergarten railing wasn't quite shaped right so...here's my start on the wintergarten upper rail replacement. I'm waiting for more brass rod to arrive in the mail before I proceed any further because I'm all out... __________________ Gwen Last edited by Gwenydd; 10-21-22 at 10:10 PM.

10-22-22, 09:09 AM	#3
Onkel Neal Born to Run Silent Join Date: Jan 1997 Location: Cougar Trap, Texas Posts: 21,289 Downloads: 534 Uploads: 224	Oh boy, I have been waiting for this The Arkmodel is designed fopr RC use, then? On the stern planes and rudders, the small screws are part of the kit out of the boy? What material are the threads the screws screw into? Are they metal or plastic? Or metal axle shafts? __________________ SUBSIM - 26 Years on the Web

10-22-22, 07:01 PM	#5
ET2SN ET2/SS Join Date: Oct 2017 Posts: 2,534 Downloads: 58 Uploads: 0	Gwen, have you tried using "loc-tite" on metal parts and screws? Its a little temperamental when compared to the super glues, but its also durable and easy to work with. You can find it in any "automotive" isle and, worst case, at any auto parts store. And, its pretty cheap. I've had good results using it on 1/118th scale die casts and even on some plastic models.

10-22-22, 07:20 PM	#7
ET2SN ET2/SS Join Date: Oct 2017 Posts: 2,534 Downloads: 58 Uploads: 0	Yeah, there's "loc-tite" then there's what I call "less-than-loc-tite" which has some fillers blended into it so the parts can still be removed. I think all of us who have a drawer full of alum. and brass tubing for scratch building have a bottle of this stuff somewhere on the shelf.