Where to fit everything?

[ConcreteTurtle]

Well, I'm finally back into building my much neglected Akula II (my starting build log is here if anyone is interested, http://forum.sub-driver.com/showthread.php?t=256).

The hull is currently waiting for a friend to drop by with his scroll saw so we can cut lexan supports in order to hold the subdriver 3.5 in place and eliminate the irritating springback in the hull halves.
While the exterior is held up a bit, I got stuck into getting the subdriver unit in good working order today.

Now I've had the whole electrical circuit wired up and working on the bench, and my hat is most definitely off to Kevin McCloud, for a fantastic failsafe and angle keeper. Likewise the makers of the MERS switch, easy and well documented. And of course the SD is so easy to work with. In short every thing I've bought from Caswell has done exactly what it's meant to so far. Thanks a lot gents.

Anyway, my question to you old hands is, how do you cram everything in here??? Every way I try to fit the 2 mini servos, LPB, MERS switch, receiver, ESC and ADF, I seem to have just a little too much going on to fit. (To be fair, Slats did warn me that this custom 3.5 would be like grand central station in rush hour, but I really had no idea!)



My first attempt was to stick the receiver and ESC to the vertical plate of the removable tray, but the dome head screw holding the ballast servo put paid to that plan.



After much head scratching, the main issue I think is where is a good spot to locate the ADF? My thoughts are that this would be the most important thing to get right, and I can try to shoehorn everything else around it? Does this sound right to you guys?

Thanks again, it's good to be back at it.

CT.

Oh, and completely off-topic, my soldering is much improved now thanks to this little beauty:



It is a great little clock kit, and very retro. (the tubes are Russian from the mid 70's, just like the submarine predecessors to the Akula)

[He Who Shall Not Be Named]

Well, I'm finally back into building my much neglected Akula II (my starting build log is here if anyone is interested, http://forum.sub-driver.com/showthread.php?t=256).

The hull is currently waiting for a friend to drop by with his scroll saw so we can cut lexan supports in order to hold the subdriver 3.5 in place and eliminate the irritating springback in the hull halves.
While the exterior is held up a bit, I got stuck into getting the subdriver unit in good working order today.

Now I've had the whole electrical circuit wired up and working on the bench, and my hat is most definitely off to Kevin McCloud, for a fantastic failsafe and angle keeper. Likewise the makers of the MERS switch, easy and well documented. And of course the SD is so easy to work with. In short every thing I've bought from Caswell has done exactly what it's meant to so far. Thanks a lot gents.

Anyway, my question to you old hands is, how do you cram everything in here??? Every way I try to fit the 2 mini servos, LPB, MERS switch, receiver, ESC and ADF, I seem to have just a little too much going on to fit. (To be fair, Slats did warn me that this custom 3.5 would be like grand central station in rush hour, but I really had no idea!)

[ATTACH]1457[/ATTACH]

My first attempt was to stick the receiver and ESC to the vertical plate of the removable tray, but the dome head screw holding the ballast servo put paid to that plan.

[ATTACH]1458[/ATTACH]

After much head scratching, the main issue I think is where is a good spot to locate the ADF? My thoughts are that this would be the most important thing to get right, and I can try to shoehorn everything else around it? Does this sound right to you guys?

Thanks again, it's good to be back at it.

CT.

Oh, and completely off-topic, my soldering is much improved now thanks to this little beauty:

[ATTACH]1459[/ATTACH]

It is a great little clock kit, and very retro. (the tubes are Russian from the mid 70's, just like the submarine predecessors to the Akula)

OK, here are some shots of a like 3.5 SD outfitted to operate a 1/72 SKIPJACK r/c submarine. Take note of how I arranged the ESC, ADF (combined fail-safe and angle-keeper), LPB and attached switch, ESC, and servos:

This schematic both presents the typical arrangements of devices within the SD, it also gives a good look at how they interconnect electrically. Note that the Lipo Guard, ESC/BEC, and LPB switch are all hard-wired in parallel with the main power cable. Device power is pulled off the receiver bus which in turn gets its 4.5-volt power from the BEC.

A fuse between the motor and ESC is recommended only if the ESC is not equipped with a heat over-load shut-down or other such motor over-current isolation feature.

http://forum.sub-driver.com/attachment.php?attachmentid=1481&stc=1&d=1254281635

The ADF (angle-keeper) is mounted on a simple aluminum vertical support that has been pop-riveted to the upper device shelf -- that shelf in turn attached to the equipment bulkhead. Orientation of the ADF is driven by what direction the stern plane servo linkage moves the stern planes as the model/SubDriver is pitched up and down. Different brand servos move in different directions (direction also depending on servo orientation within the SD).

Note that 'servo tape', a double-sided self-adhesive tape with a foam core, is used to mount the device to the aluminum support.

http://forum.sub-driver.com/attachment.php?attachmentid=1477&stc=1&d=1254281635

The devices that go into the SubDriver: servos; ADF (fail-safe and angle-keeper); Lipo-Guard; receiver (I found the one pictured here to be defective and replaced it with the six-channel Sombra receiver); LPB with attached switch; and ESC and BEC.

Note the aluminum LPB foundation I pop-riveted to the lower portion of the equipment bulkhead. The ESC-BEC is later jam-fit between the bottom of the upper shelf and top of the LPB motor.

http://forum.sub-driver.com/attachment.php?attachmentid=1478&stc=1&d=1254281635

A good close look at the mounted LPB. I used a nylon electrical ti-ti to secure it in place. Nothing fancy. Keep it simple, stupid!

http://forum.sub-driver.com/attachment.php?attachmentid=1479&stc=1&d=1254281635

Here were looking at the outfitted SD motor bulkhead -- that is to say, every device has been mounted within and tested for correct operation. This view is of the underside. Note that I make use of quick-disconnect plugs between the ESC and the motor and battery cables. I use ti-ti'es to keep the various wires nice and tidy. See how I've crammed the ESC-BEC between upper device shelf and LPB motor.

Just one way to get ten-pounds of 'the brown stuff' into a five-pound bag, boys and girls.

http://forum.sub-driver.com/attachment.php?attachmentid=1480&stc=1&d=1254281635

[ConcreteTurtle]

Many thanks David,

That's some masterful cramming there.

Your electrical circuit is very similar to what I had up and running on the bench last weekend, glad to know I'm on the right track. I had however omitted the 10A fuse to the motor, I'll add it to my burgeoning to-do list.

Sadly the nifty LiPo guard is out, the A123 batteries I'm using have different chemistry giving a lower cell voltage. Thankfully, they should be a lot more tolerant of low voltage and not as excitable as the LiPo alternative...

The plan is to use Slats rather good watertight connector scheme in place of a mission switch on the battery WTC.

Your angle keeper installation is great, that will surely help out in fitting everything into these guys.



I'll get some time to cram this weekend, will keep you guys posted on progress.

Cheers, and thanks again.

CT.

[Kazzer]

The plan is to use Slats rather good watertight connector scheme in place of a mission switch on the battery WTC.

CT.

Where? Where? What did I miss here?

[ConcreteTurtle]

I don't think that Slats will mind me posting this (apologies if so), but he's got an excellent description of his system in his technical album: http://forum.sub-driver.com/album.php?albumid=21

He's brought it up before on the forums, and having seen it in the flesh, it's a great bit of ingenuity.

Cheers,

CT.

[He Who Shall Not Be Named]

Holy crap, CT! What did you do ... chop off some of the dry space cylinder -- I don't see any room for the servos in there!!!!????

Please God, tell me I didn't send the cylinder to you (through Caswell) in that condition!

Listen, don't sweat the motor fuse if your ESC is overheat/current protected. That drawing represents 'old school' conservatism and represents my effort to protect the ever vulnerable (until I ran across the MTronics line) ESC from a stalled motor.

And tell us more about those Iron batteries you're using.

Hey! ... you going to listen to a guy stuck on Her Majesties Prison Colony or me!??

Hurrumph!

David,

[ConcreteTurtle]

Hi David,

Well, that's the way our good lord Merriman made her, she was custom 3.5" for an alfa hull. I'm just glad I'm not being a big crybaby about the space available, being the first SD I've had and all...

I will omit the fuse (along with some of the tamiya connectors maybe, to free up space). The ESC is a mtroniks 15A, and from the info on their website it seems to have overload protection onboard.

The A123s are pretty darn good little batteries from what I have seen so far. I stripped this set of 10 cells from a DeWalt 36V cordless drill pack about 6 months back.
They are LiFePO4 chemistry and run at 3.3V, 2300mAh nominal per cell.
I'm running 4 cells total in the WTC, 2 sets of 2 cells in parallel. This gives about 7.1V at a full charge and 4600mAh capacity for about 11oz of weight.
The big difference over LiPo is that they can be discharged and charged much faster. (The electric ducted fan guys "zip charge" them using lamp flex and a car battery from empty to full in about 8-12 mins!). They also handle deeper discharge without damage and the general experience is that they don't catch fire when mistreated or charged incorrectly.

The proof is in the eating, so I'll stay my judgement until I've got a few cruises under my belt, but they are shaping up nicely...

It's only because us colonials have to look out for each other. ;)

CT.

[He Who Shall Not Be Named]

Hi David,

Well, that's the way our good lord Merriman made her, she was custom 3.5" for an alfa hull. I'm just glad I'm not being a big crybaby about the space available, being the first SD I've had and all...

I will omit the fuse (along with some of the tamiya connectors maybe, to free up space). The ESC is a mtroniks 15A, and from the info on their website it seems to have overload protection onboard.

The A123s are pretty darn good little batteries from what I have seen so far. I stripped this set of 10 cells from a DeWalt 36V cordless drill pack about 6 months back.
They are LiFePO4 chemistry and run at 3.3V, 2300mAh nominal per cell.
I'm running 4 cells total in the WTC, 2 sets of 2 cells in parallel. This gives about 7.1V at a full charge and 4600mAh capacity for about 11oz of weight.
The big difference over LiPo is that they can be discharged and charged much faster. (The electric ducted fan guys "zip charge" them using lamp flex and a car battery from empty to full in about 8-12 mins!). They also handle deeper discharge without damage and the general experience is that they don't catch fire when mistreated or charged incorrectly.

The proof is in the eating, so I'll stay my judgement until I've got a few cruises under my belt, but they are shaping up nicely...

It's only because us colonials have to look out for each other. ;)

CT.

A 'custom' job. OK. I'm off the hook -- I'll blame the customer. There! My hands are clean.

Omit the equipment bulkhead after facing shelf, mount an aluminum servo tray between the two equipment rails, between the after end of the motor and the equipment bulkhead -- this will be the firm foundation you need to secure the servos. Put the ESC under the servo tray. That leaves room for the receiver and ADF but little room for the LPB (only the small one, not the big one I illustrated a few posts ago).

You're using an MTronics ESC -- you don't need the fuse.

I know Mr. Caswell will try to kill me for asking. But ... here goes: Are these Iron batteries now accepted by the high-performance end of this hobby (r/c aircraft, cars and hydro's)? If so that would mean an established infrastructure of battery, charging, and service support. I don't want to find ourselves, Caswell/Merriman, behind the cure on this thing. And how is the power-density of this type battery compared to the Lithium-ion/Lithium-polymer?

Let's get that ALFA of your working!

David,

[Rick Teskey]

lifepo Vs lipo

What is the weight /size comparison of a123 compared too the equivalent lipo say a 2 cell (2s) 7.4 3000 mAH? ( 135x43x12 mm and 189 grams) ( God I hate metric!!!!)
I am in the process of switching from nicad and nickel metal to lipo, which are half the weight.
On another note, whose leg do you have to hump to get a promotion on this board?
If it goes by number of posts then one time poster "jungle Lord " must have made commander and chief or Admiral at least!
Rick

[He Who Shall Not Be Named]

What is the weight /size comparison of a123 compared too the equivelent lipo say a 2 cell (2s) 7.4 3000 mAH? ( 135x43x12 mm and 189 grams) ( God I hate metric!!!!)
I am in the process of switching from nicad and nickle metal too lipo
which are half the weight.
On another note, whos leg do you have too hump too get a promotion on this board?
If it goes by number of posts then one time poster "jungle Lord " must have made comander and chief or Admiral at least!
Rick

I hate chronic posters, Rick! I grade a posters utility as an inverse slide: the more he posts, the less respect I have for him.

Mike and I have structured the site so that once you hit the secrete post number we contact your local Teamster's lodge and arrange to have you killed. A Texas style funeral, if you know what I mean kiddo.

(seen Jungleload here lately?! ... hear that faint thumping sound at the cemetery?).

David,

[Subculture]

Best write-up on A123 cells I've found on the web-

http://www.flyelectric.ukgateway.net/lithium-a123.htm

These cells have to be the best batteries for subs, period. They are a little expensive up front, but when you consider their cycle life and other advantages, they're a cheap battery technology.

[He Who Shall Not Be Named]

Good stuff, Andy. Thanks.

David,

[Kazzer]

(seen Jungleload here lately?! ... hear that faint thumping sound at the cemetery?).

David,

Oh my aching sides! Where does he get these gems from?

[He Who Shall Not Be Named]

Oh my aching sides! Where does he get these gems from?

Too many viewings of the Kill Bill movies.

David,