1/72 OTW Trenchant with 3.5" Subdriver

[Slats]

I'll be posting here shortly photos etc of my 3.5" D&E Subdriver that I have on board my 1/72 OTW HMS Trenchant.

In the meantime here are some photos of the boat (almost finished) she needs some fine details and weathering added. Re the tiles on the outside these are everygreen styrene tiles glued on in small groups of around 1 square inch at a time. I have undertaken extensive testing of this method including exposing the tiles to rapid heat / cold changes. I like the tiles on the boat as they allow me to best depict this feature that seems prominant by their patchyness - as they seem to always come off these boats from time to time.

The sail / appendages (rudders & planes) are scratch built and are not part of the OTW kit.

I have done some preliminary ballasting but need to do some more fine tunning of the trim, as I discovered that I did not correctly fill the gas tank with much propel - I thought I'd chilled it down enough - but I don't think the tank was full - judging by what I emptied out after ballasting.

enjoy.....



Best
John

[toppack]

Hello, John
Very Interesting. Great Job!
Thanks for the Info and pictures. :)
What type battery did you use?

[Slats]

Hi
battery is a 7.2 volt NimH 4600 mA that I placed in a forward 3" WTC section.
I connected this to the 3.5" forward end cap of the Subdriver's ballast tank.

I find (albeit in the test tank), that this power coupled with the Subdriver's 7.2v motor is more than enough grunt for the subs pump jet.

I know NimH is old school compared with newer Lipo batteries but I am very happy with this setup.

Will post photos soon - just busy at work at the moment.
Thanks

John

[toppack]

Yes, I'm an 'old school' guy myself. I'm thinking about using a Gel-cell with my 3.5", that I have on order, which is even Older School battery. :D
That way I won't need a WTC for it and I won't need any ballast-lead in the bow.

[Slats]

Yes I have used an SLA before but I don't like too much weight in my boats.
Of course it depends on the boat too. Too much weight is not simply overcome by adding more foam - weight is not just a trim consideration but also a consideration of how the boat handles in the water. More weight the greater the mass momentum and the boat wanting to stay on a track - harder it can be to turn.

The other consideration is the amperage / weight ratio - much higher amps / weight in niMH than SLA, and in my case I like the mating of a 7.2 Volt battery (not available in SLA) with the Subdrivers 7.2 volt motor. I could have used a 6v SLA, but again I like its still was a better amps / weight in niMH than SLA.

You could always order a small 3" battery unit that is on the website. I am not sure if that is big enough for a NiMH 7.2 volt stick pack - Mike or David will know.

John

[toppack]

I don't know for sure how a Gel-cell will work out in the 1/48th scale, I'm planning to try it in, either. If it doesn't, like you said, I can always get a WTC for it.
I wanted to try them first since I already have some good Gel-cels, in various sizes, left over from surface ship projects. :D

I didn't realize that the motor used in 3.5" SD was rated at 7.2 volts.
Is that the nominal voltage rating? I thought it was higher than that, like 12. volts or so?

[Slats]

I don't know for sure how a Gel-cell will work out in the 1/48th scale, I'm planning to try it in, either. If it doesn't, like you said, I can always get a WTC for it.
I wanted to try them first since I already have some good Gel-cels, in various sizes, left over from surface ship projects. :D

I didn't realize that the motor used in 3.5" SD was rated at 7.2 volts.
Is that the nominal voltage rating? I thought it was higher than that, like 12. volts or so?

Wow 48 scale is big - and perhaps therefore less of an issue using an SLA.

I think you need to specify the Subdriver motor voltage when you order - I have seen David use 12v SLAs with some 3.5" Subdrivers, mine is clearly marked as 7.2v motor which I feel is very adequate for the subs I plan to use it with.

J

[toppack]

David & Mike,
What's the story on Voltage Rating of the motors supplied with various SD sizes?

[He Who Shall Not Be Named]

David & Mike,
What's the story on Voltage Rating of the motors supplied with various SD sizes?

I stick what I have in those SD's. Currently I'm fat with 12-volt motors.

David,

[toppack]

I understand, Good Choise. ;)

[Slats]

I understand, Good Choise. ;)

Well the fact you bought a subdriver is a fantastic choice itself.

12v means you can run that SLA as you want. Just wondering what 48 scale boat is that and do you have a thread here on it.

BTW what is you name?

[toppack]

Well the fact you bought a subdriver is a fantastic choice itself.

12v means you can run that SLA as you want. Just wondering what 48 scale boat is that and do you have a thread here on it.

BTW what is you name?

Yes, 1/48th scale boat is 'British T-class' thread in this forum section.

Name is Rick.

[Slats]

I have not yet left any other site I post too.
If you must know guys - the censorship that annoys me most is not swear words, but the deliberate silencing and removal of references to David's excellent products and the inhibiting of me supplying others with links on that site to those products should others ask questions of those products. Yes I support decency and politeness but I will never understand or support the censorship that the site in question has, which is in fact blatant discrimination, albeit in a passive way. I am not involved in any way with any agenda other than my own. I am aghast at such fear in some who inhabit what I believe is one of the greatest models of democracy the USA.

I have been in the sub and target RC game, along time - before the net existed. I do like forums for furthering the hobby, my enjoyment, scholarship, and helping others do the same, but I will survive if pushed out of one.

Hope that clears the air - so lets get this post back about my HMS Trenchant and its sub driver.

I did some re ballasting in my test tank and not surprisingly using David's method of filling the propel bottle (see post on this), the sub was heavier. I clearly had a full propel charge which weighs more.

I also fully inspected the boat as she went negative by removing the top section - this was good to inspect that the boat had indeed fully flooded the tank. NB, Davids advice:
On the surface the tanks is empty
Dived the tank is to be full not half FULL

Suffice to say I am affixing a little more foam.
Photos on this coming soon.

best
John

[Slats]

On thing I did notice is Trechant's relatively flat deck and lack of top side vents is a problem.

I am getting an air bubble stuck underneath the deck. I have tried drilling small holes that would be for the safety rail uprights (used when the boat is in port), but is there another way to alleviate this?

John

[Nuke Power]

holes are the only way sometimes. I have had to make non scale holes just to get my boats to drive right. It came down to, is it gonna look super pretty in its stand or is it gonna work how I want in the water.

[He Who Shall Not Be Named]

holes are the only way sometimes. I have had to make non scale holes just to get my boats to drive right. It came down to, is it gonna look super pretty in its stand or is it gonna work how I want in the water.

Kevin's right -- sometimes you gotta bite the bullet and punch those holes into the deck. Here are some hard-and-fast rules to insure you get those bubbles out:

1. Make the vent holes at least 1/8" in diameter (too small and surface tension between the bubble and water will be strong enough to prevent escape of the air)

2. Bevel under the hole to minimize the thickness of the holes bore

3. And grease the underside of the deck to keep bubbles from clinging to the underside of the deck (the grease reduces the air-bubbles ability to 'stick' to the underside of the deck).

David,

[Slats]

Kevin, David, thanks guys,

my holes were trying to keep with scale fidelity and I did notice the bubble seemed to span the hole diameter I had. I'll add some 1/8" ones and make the minimum size that size. I'll then re-test / trim her.

Re the grease would vaseline be ok?

Best

John

[Nuke Power]

Vasoline... what ever you like sailor :)

[toppack]

I don't know what Sailors prefer :D
but I like Silicone-grease.

[Nuke Power]

yes i prefer silicone aswell. KY is soluable and will dissolve once you submerge.

[He Who Shall Not Be Named]

Kevin, David, thanks guys,

my holes were trying to keep with scale fidelity and I did notice the bubble seemed to span the hole diameter I had. I'll add some 1/8" ones and make the minimum size that size. I'll then re-test / trim her.

Re the grease would vaseline be ok?

Best

John

Yup, the Vaseline will work just fine.

David,

[He Who Shall Not Be Named]

yes i prefer silicone aswell. KY is soluable and will dissolve once you submerge.

... don't make me stop this car!

David,

[Slats]

Ok more tank testing and some photos too.

Here you can see Trenchant in the wet stuff. I drilled the upper deck with some more openings and still needed to add a tad more weight. I do run my boats slightly positive as I run in a lake where visibility in some areas is patch at best.

That said she is too positive still.

The subdriver photos show here that I use a 3.5" single screw subdriver and have connected forward of the ballast tank a 3" enclosure for the 7.2 v battery.

David / Mike, what would it cost to have a connecting end cap like the two I have connected between the battery compartment 3" and the BT 3.5"?
I used some threaded brass rod to join the end caps and glued them together. I added a battery tray to the 3" battery compartment.

This is a very nice boat and I do like the colour scheme - it will be good for 4 eyes here to see it too in this pattern. I have added some weathering - scum line and removed some tiles too.

All up I like it.

Best

John

[Slats]

sorry helps if I add the photos....

[Slats]

here is some more photos

[He Who Shall Not Be Named]

Ok more tank testing and some photos too.

Here you can see Trenchant in the wet stuff. I drilled the upper deck with some more openings and still needed to add a tad more weight. I do run my boats slightly positive as I run in a lake where visibility in some areas is patch at best.

That said she is too positive still.

The subdriver photos show here that I use a 3.5" single screw subdriver and have connected forward of the ballast tank a 3" enclosure for the 7.2 v battery.

David / Mike, what would it cost to have a connecting end cap like the two I have connected between the battery compartment 3" and the BT 3.5"?
I used some threaded brass rod to join the end caps and glued them together. I added a battery tray to the 3" battery compartment.

This is a very nice boat and I do like the colour scheme - it will be good for 4 eyes here to see it too in this pattern. I have added some weathering - scum line and removed some tiles too.

All up I like it.

Best

John

Let me get this straight, John: you're looking for a 3.5/3 union coupler? If so, we don't make 'em yet, but a good idea. I could develop that for you: make the masters, tools, and parts. But, only if we (Caswell/D&E) can be assured sales of additional units to other customers; is there a market for this interface piece.

Mike: might be a worthwhile product. Want me to do it, or do we just sell John the two separate bulkheads and let him do the grunt work of attaching them?

David,

[Nuke Power]

They can be usefull for people making your fav rcab system. Also good since you never add a space to put a sport pack battery. Laot of people would like the battery and everything in ne whole unit without having to use lipo.

[Slats]

David,
I'd like one, as I feel a moulding would be so much better than the way I affixed mine together. That said they way I have it ain't broke - it works just fine.

If not commercially viable - don't worry about - I complete understand and I am sure others will too. We live in the real world.

The 3.5" Subdriver could easily be coupled to an SLA in the wet area. I choose a NimH pack as I have a 7.2 V motor in the 3.5" SD I have, and like the idea of using the 7.2V bat pack over going wet (and I must say heavier), with the SLA.

Having the battery pack section join the ballast tank, just makes IMO the whole SD look neat and tidy as one whole package. Indeed that's what I love about the original 3" D&E Subdriver is that its so neat and tidy. Of course that SD has the electricals inside, here in mine they are external.

Best
John

[toppack]

I like being able to remove battery without disconnecting the complete sub driver. That's one thing I like about the 3.5 design, over the other SDs. :)
Also gives more options in weight positioning.
(I realize it needs to be all in one assembly for the very Small versions, tho.)

[Slats]

I like being able to remove battery without disconnecting the complete sub driver. That's one thing I like about the 3.5 design, over the other SDs......

Yes very good point, my on / off switch is the simple removal of a positive plug (which is waterproofed) off its pickup on the external battery compartment end cap.

That said if the SD with all internal pwr hooks up etc is inside the SD, depending on how much access you have I find its not that difficult to take off the forward batt end cap (with the boat on the stand of course) and change batteries that way. I have to say though I am pretty anal about checking my gear, so if I need a new battery I have typically ran the sub for quite a while, and like a high performance piece of gear I retreat to the pits to make sure its all OK and take her out for some rest and inspection.

I'll show you how I do the waterproofing of the external hookups with some more photos later. Its very simple and it works!

Best
John

[Slats]

I am going to have a go here at adding the pictures (thumbnailed before) from my Album...so if you have seen these before- you have!

In the test tank


As you can see here she is still TOO positive with a full propel charge and fully flooded ballast tank
http://forum.sub-driver.com/picture.php?albumid=7&pictureid=13

The tile work on this boat is Evergreen styrene tiles - glued on with Green ZAP CA. These are glued on in groups of tiles no more than around a square inch at a time.

[Slats]

I am going to have a go here at adding the pictures (thumbnailed before) from my Album...so if you have seen these before- you have!

In the test tank
http://forum.sub-driver.com/picture.php?albumid=7&pictureid=14

As you can see here she is still TOO positive with a full propel charge and fully flooded ballast tank
http://forum.sub-driver.com/picture.php?albumid=7&pictureid=13

The tile work on this boat is Evergreen styrene tiles - glued on with Green ZAP CA. These are glued on in groups of tiles no more than around a square inch at a time.
http://forum.sub-driver.com/picture.php?albumid=7&pictureid=12

[Slats]

Wow that worked - now that is a cool feature of this forum!
Thanks Mike.

John

[Kazzer]

Damn! I'm good!! (Isn't that Merriman's line?)

[Nuke Power]

Yeah it is so stop stealing it!

[Kazzer]

Yeah it is so stop stealing it!


Weak Knee'd

How about this one? Sounds like Merriman?

[Slats]

more bigger pictures within the thread.


Here is the Subdriver in the sub on the bench.
http://forum.sub-driver.com/picture.php?albumid=7&pictureid=9


Next is the Engineering space of the Subdriver. Note the use of Mid sized Hi Tec servos. Even though these are mid sized Hi-tec calls them micro.
These have exactly the same torque as the Futaba S148 normal sized servos, so they can push with ease the 1/8" push rods.

Specs are:
HITEC HS-81
SUB MICRO SERVO
Torque (4.8/6.0V): 2.6/3.0kg.cm
Speed (4.8/6.0V): .11/.09sec/60deg
Size (LxWxHmm): 30x12x30
Weight (g): 16.6

I like these as my local hobby store sells these for the same price as a regular servo, the size is attractive as I simply hate too much clutter in there.


http://forum.sub-driver.com/picture.php?albumid=7&pictureid=10



Finally here is the forward battery compartment. The tape used here is I found that ever since I shortened the BT by an inch the O'ring seal on the ballast tank (whilst still fitting snug and being air tight) seems a bit looser.

Note that the 3" WTC I have for the battery compartment has its rear 3" end cap connected to the BT 3.5" end cap at the lowest position. This is done to keep weight in low position.

http://forum.sub-driver.com/picture.php?albumid=7&pictureid=11

Also note in the WTC photos the use of velcro to hold down the WTC. The velcro is expoxied to the lower hull halves. The WTC also has in the ballast tank a small 1/8" hole to line up with a 1/8" brass indexing pin to align the cylinder up in the boat.

[Slats]

Had a fantastic day out with the guys at Task Force 72 with Trenchant.

Weird that I actually had to "manually" reset the M-tronics ESC - after about 20 minutes sailing the unit I think had a programing glitch and cut all FWD propulsion. Resetting the ESC did the trick. (Anyone else have this glitch?)

I had a real 1/72 scale RN "Loyal" class tender that accompanied me. I played chicken - no deeper than PD in these waters - where the tender and sub are is really deep.

No leaks and no problems got to love the SD with LPB "snort system".

Best

John

Backing out slowly
http://forum.sub-driver.com/picture.php?albumid=7&pictureid=184


Getting up close to Loyal tender
http://forum.sub-driver.com/picture.php?albumid=7&pictureid=185

Loyal doing some touch parking
http://forum.sub-driver.com/picture.php?albumid=7&pictureid=186

Guys given my considerable fleet and another 4 subs within it, I will be selling Trenchant complete ready to run - Australian buyers only as I don't plan on shipping her OS and the Frequency 36MHZ is legal here. If interested PM me.

Best

John

[Nuke Power]

I do wish I could sail a boat in Australia. Trenchant would make a good first :)
You just moving on to the next boat John?

[Slats]

I do wish I could sail a boat in Australia. Trenchant would make a good first :)
You just moving on to the next boat John?

Yes going all out now on the Collins and have Joel Stadnick's Permit arriving soon. I'd like to have both running well for Summer (that's December here).
Add to that my numerous targets and I decided to let he go. Trenchant has been largely an experimental boat for me - the tiles on the GRP plus the pump jet - wanted to give something new ago. Its been a boat that I slotted into a gap I had due to some local supplier failures.

Best
John

[Nuke Power]

just surprising considering how long you have had it completed

[Slats]

just surprising considering how long you have had it completed

Yes but had a good playtime with it.
I have a significantly large target fleet too - that I have also have to cut back a bit on.


Here is some more play photos.
http://forum.sub-driver.com/picture.php?albumid=7&pictureid=188

http://forum.sub-driver.com/picture.php?albumid=7&pictureid=187

Heck I might just keep her!
She is nice!