HMK 1/72 Permit - USS Plunger

[Slats]

I ordered from Joel at HMK many many months back a 1/72 Permit kit, a couple of months the kit arrived, but its only been in the last few days I could get on to it.

Herein is going to be my assembly of this amazing kit. You will note I use the term assembly - its appropriate to call it that as its not building per se. The kit is a feat of precision structural engineering and Joel demonstrates a very high degree of attention to detail leaving the end assembler with what should be a very straight forward build (assembly). What is most apparent from the kit is how complete it is. Joel supplies just about everything you need to get this lady wet save for tools, (although some allen keys are included), paint, adhesives, ballast, WTC.

The kit purely from an out of the box perspective gets top marks, in terms of what you won't have to worry about. Its packaged carefully and methodically, and comes complete with parts list and whopping great manual of construction, and plans.

I hope to give Joel's fine kit justice here at SDs and expect all to jump on me if and when I head astray.

Film at 11.
The fun starts now.

[Slats]

Ok first order of business is to get a good spot to work.

Here you can see I have mounted the plans on the wall and have a whole workshop bench cleared for the work.





Next order of business is to carefully inspect you have all the parts - I think I do, there are some small parts that I made need help ID'ing as the build progresses.

Parts packed in bags - great for keeping them all together.


That great manual and parts list


After parts ID, you need to wash any mold release still present on the parts off. The instructions recommend some dish washing liquid and soap pad in some water, I prefer this plus a light 1200 wet and dry once over. This parts clean up is necessary - don't do this and you will have poor adhesion throughout the assembly and a resulting mess. Paint also won't adhere well.

Shown below is not a defect but some green film like mold agent left on. This is not laziness on Joel's part, but rather an extra protective layer that is handy for the shipping process.



Parts after washing - this shot shows the mass of what's included

[Subculture]

Probably the most slippery class built, hope you'll run it fast.

[He Who Shall Not Be Named]

Two points:

I agree with all the kind words John said about this kit -- I have one too and can't wait to get to it. Joel is an amazing talent and this kit is a killer! It's official now, I truely hate Joel.

And, if I'm not mistaken (I've just filled the order placed through Caswell) John will be installing our two-motor-on-one-shaft 3.5 SubDriver; that's two 550 motors working one shaft through a 5:1 gear reduction.

That should swing the 1/72 PERMIT's big wheel with a great deal of authority, Andy! That boat will scream! Pictures of that prim-mover below.

Hey, John: how do you paste pictures in the text? ... I'm such a dumb-ass at this.

David,

[Slats]

Hi David,
yes Indeed - the power plant I have ordered will be for this Permit. Mike and Lance now need to take my money and ship it!

A quick question David, I have told Joel, that I will use the Carbon firbe prop supplied, but I was thinking of going the brass route. To take advantage of all that torque on offer what are your thoughts on the supplied carbon propeller versus going brass?

Re posting photos.
Simple.
1- Go to your user CP - make a photo album, upload photos.
2- Open a second window of SD Forum
3- In the second window - write up your post to the board.
4- Go back to the other window with your photo album and open up the photo you want to stick in you post. You will see the code below the photo begin with [IMG\. Copy the whole line.
5-Go to the window where the post is and paste the line in.
Presto - large photos in your post.

J

[He Who Shall Not Be Named]

Hi David,
yes Indeed - the power plant I have ordered will be for this Permit. Mike and Lance now need to take my money and ship it!

A quick question David, I have told Joel, that I will use the Carbon firbe prop supplied, but I was thinking of going the brass route. To take advantage of all that torque on offer what are your thoughts on the supplied carbon propeller versus going brass?...

John,

Thanks for the dope on the photos. I'll give it a shot after I address this post.

Good, I want to see what you do with that motor-bulkhead.

We're crossing the line where resin (even re-enforced resin) and white-metal propellers will fail with the higher loads being presented with the higher torque running gear. Time to go brass (cast or soldered).

God! ... I hate wax work!

David,

[Slats]

Probably the most slippery class built, hope you'll run it fast.

Yes it will move - I have assembled a 1/72 Permit many years back - in fact it was my first scale RC sub. This was a Ships N Things Permit - fairly basic but good fun for the price I paid. That sub was very quick. Speed aside, nothing I like more than creepin along at the lake and sneaking up on people. The boat will have a couple or maybe 4 Merriman warshots - when there ready.

For the new guys out there - high speed in blue water ops like a deep lake should be avoided until you are confident at the helm and can control the boat at PD. I tend to go nuts for speed in controlled waters like olympic pools.

J

[ManOwaR]

John,
I can't wait to see how this boat is going to look. I know it will be good, because judging by how beat up and worn out that poor work bench and vise of yours looks means this won't be your first canoe ride...the mark of the craftsman!

As always, feel free to ask any questions and I'll do my best to get an answer to you promtly.

Joel

[Slats]

David,
I am having a tough time getting my head around why two motors through the g/ box will mean better run times. I get why the torque increases, but the electrical load of two motors is still puzzling on battery draw....Is this because the motors are sharing the work that the draw is less?

J

Joel,
Thanks -I try to build a little every couple of days.

Mike,
sent you an e-mail re the brass prop. Raboech make em.
The one you previously got for me might be ok.
J

[Slats]

Ok the brass prop required is made by Raboesch Precision Engineering no.179-17 its 63mm diameter, 7 blade Scimitar, right hander.

Mike stocks Raboesch props but not sure if he has these in stock.
J

[Subculture]

Prefer Prop Shop. Solid lost wax cast in silicone bronze. Mmmm!

[He Who Shall Not Be Named]

David,
I am having a tough time getting my head around why two motors through the g/ box will mean better run times. I get why the torque increases, but the electrical load of two motors is still puzzling on battery draw....Is this because the motors are sharing the work that the draw is less?

J

Joel,
Thanks -I try to build a little every couple of days.

Mike,
sent you an e-mail re the brass prop. Raboech make em.
The one you previously got for me might be ok.
J

That's right, John, I figure two motors, splitting the load, will be a bit more efficient than a single motor working at its top-end. So -- and only practical experiment will reveal if this is true or not -- I figure that you'll be cruising along most of the time at a 1/3 bell, and will high-throttle the thing for only a fraction of the total run time between charges. The two motors will give you a bit better total propulsive efficiency than a single like motor, and they will give you the kick-ass torque at the top end to make this submarine of yours fly.

You'll likely be the first guy in the water with this type SD, so your report from the field will tell the tale as to wether or not I've got this right.

You're my lab-rat, pal.

David,

[Slats]

Well the lab rat build continues.....

The lab rat like his - lungs - whenever you are doing any sanding, cutting, or glassing - you need protection.


Whenever I build a sub - I make what Cameron Glassford here in Australia calls a strong back stand. Its basically a flat piece of wood that has two sides to it. The job of this is not a boat stand but to enable the hull to be firmly secured whilst I do various things to it.




Above, here you can see some the sub with some flood hole started in her with the whole lower hull sitting in the strong back. The width of the two side timbers is just enough to take the extreme beam of the hull. If you are working alone and lets face we all do it I find this a nice platform to keep the boat firmly in position.

Next item of business is the Z cut - where you cut off a lower bow section - adjoin it to the forward bow, cut off an upper tail cone section and adjoin it to the lower hull. In doing so you remove with two equal cuts an equal amount of materrial in the cuts themseleves and hence should get a seamless join for and aft for the hulls.

Joel's instructions recommended a 3" cut forward in the bow of the lower hull and a 3.5" cut in the stern section. Joel has advised me since that you can just lop off the bow on the demarcation line of the sonar dome and for the rear cut just aft of the MBT vent - so as to have an adjoining screw lookalike a twin MBT. I did precisely this for the bow and for the stern I made the cut just AHEAD of the MBT - as I prefer to try and seal this sucker with one screw but should have taken Joel's advice here. I can still install a rear securing screw if necessary, and it will be.

Here you can see the strong back stand - where everything is at right angles - I use it with a 3" diameter WTC lexan tube to mark up my stern cut. In making these cuts I prefer taking my time with a razor hobby saw, and gentle score a groove for the blade to follow.


I use the sonar demarcation line to cut the lower bow off.




Rough up the insides of the bow pieces and the stern cone pieces.

This is so to have good adhesion of joining the lower bow to upper hull, and upper cone piece to the lower hull. Joel recommends the initial joining is via ZAP CA type glue and some baking soda to catalize this - I prefer kicker via a dropper. Joel recommends that the join is then made permanent with fibreglass tape in epoxy resin. I am unsure as to what fibreglass tape is so I simply cut out some fibreglass matting and applied it with expoxy resin. - Same effect I guess.

The initial join upper hull to lower bow piece with CA glue




After CA preliminary adhesion of the lower bow piece and upper cone tail section the sub should come back together neatly.

[Slats]

Here you see construction of a pressure ballast tank - USS Plunger and my HMAS Rankin will feature a new type of WTC / SD.
Free flood main BT that clears at PD via a snort. This main tank takes to the boat to decks awash from the correct surface trim but it will not take her down further. A geared pump and solenoid check valve which takes the sub all the way down via a sealed tank within the centre of the main BT. This small tank under pressure also surfaces the boat back to decks awash from depth. I was going to use a sphere but all the sphere toilet valves I could get here were either two big to fit into the 3.5" lexan or too small to effectively be a trim tank or final submerge surface tank. The PVC fittings are pressure ones and are cemented together with pressure cement. I will need a couple of small baffles in this tank. I have been using PVC pressure tanks for years as a sole ballast tank - much bigger than this of course but this new combination system of tank within a free flood tank means minimising slosh and heaps of baffles. It also means a smaller tank - as having this setup as a main ballast tank means about 40% will be compressed air.



OK - here is where I need help - Joel and or those who know much of these boats post 79' details and the intro of the mini sail - can you please ID herein what is what and where it goes. My plans do not show the mini sail config.
Joel in his later version of this kit now supplies a fantastic scope rack - a guide system where by you have good firm support of the scopes etc - but you must install this BEFORE the sail planes. So please jump in here and tell me where things go please.
Thanks

[Slats]

Next up if I may digress a little - here is an impending space problem with the Permit's and for that matter Sturgeon's and LAs, should you wish to fit torpedos. The angle off the bow (10 degrees - please correct me), will invade a 3.5" cylinders space. My work around will be a 2" tube for the battery adjoined to a bigger 3.5" cylinder.