Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: Telusboats on February 06, 2015, 07:30:54 am

Title: U47 robbe tech rack
Post by: Telusboats on February 06, 2015, 07:30:54 am
does anyone have plans for a tech rack for Robbes U47 that will accommodate the Engel 750 ml tank?
Title: Re: U47 robbe tech rack
Post by: essex2visuvesi on February 06, 2015, 09:50:32 am
There's a company called pirahna models in Germany that offer one for sale


http://www.modelluboot.eu/Preisliste.htm


The website isn't very good but drop the chap an email and he'll send you all the information and pics you need.  I have the Sea wolf Tech rack awaiting construction in Finland
Title: Re: U47 robbe tech rack
Post by: Subculture on February 06, 2015, 05:46:15 pm
There's another outfit that produces a plastic tech rack, that looks almost identical to the type fitted in the Engel Lafayette.

Don't know if they have a website, but if you're on the book of faces, they have a page there-

https://www.facebook.com/pages/Modellbau-Wikinger/753073014783452

(http://img.photobucket.com/albums/v293/subculture84/u47tech_zps80513f50.jpg) (http://smg.photobucket.com/user/subculture84/media/u47tech_zps80513f50.jpg.html)
Title: Re: U47 robbe tech rack
Post by: subkraft on February 14, 2015, 02:44:50 am
.....strange. My previous posts, images and responses have all disappeared from this thread.
Is this common?
Title: Re: U47 robbe tech rack
Post by: Telusboats on February 14, 2015, 03:19:00 am
What happened to all the posts?
Title: Re: U47 robbe tech rack
Post by: subkraft on February 14, 2015, 04:04:40 am
.....not just me then
Title: Re: U47 robbe tech rack
Post by: salmon on February 18, 2015, 02:39:17 am
If I was to hazard a guess, modelboatmayhem has had its fair share of database errors or site wide outage. I wonder if during the work to get it back and running, some data was lost. Admin, can you help?
Title: Re: U47 robbe tech rack
Post by: Tug-Kenny RIP on February 18, 2015, 10:38:59 am


We did loose a days input, so a few letters cannot be recovered.

ken

Title: Re: U47 robbe tech rack
Post by: subkraft on April 28, 2015, 04:39:49 am
....anyone interested in starting again?
Title: Re: U47 robbe tech rack
Post by: Telusboats on April 28, 2015, 05:11:37 am
I would as I am working on a u47.
Title: Re: U47 robbe tech rack
Post by: hmsantrim on April 28, 2015, 10:46:18 am
 Hi.
 one here.
 http://www.ebay.de/itm/U-boot-Technikgerust-passend-fur-Robbe-U-47-Modelluboot-/161681536847?pt=LH_DefaultDomain_77&hash=item25a4f8774f (http://www.ebay.de/itm/U-boot-Technikgerust-passend-fur-Robbe-U-47-Modelluboot-/161681536847?pt=LH_DefaultDomain_77&hash=item25a4f8774f)
 
frank
Title: Re: U47 robbe tech rack
Post by: Telusboats on April 28, 2015, 04:04:21 pm
I am in Canada and would like to avoid transactions that are from outside North America. Is it possible for someone to send me the templates or instructions for the tech rack?
Title: Re: U47 robbe tech rack
Post by: TomHugill on April 28, 2015, 08:10:47 pm
You should have no trouble getting them posted, sent plenty across the pond with no issue.
Title: Re: U47 robbe tech rack
Post by: Telusboats on April 29, 2015, 03:57:16 am
Posted, as in by the mail system?
Title: Re: U47 robbe tech rack
Post by: TomHugill on April 29, 2015, 10:49:22 am
Well I think the carrier pigeons would struggle to cross the pond...
Title: Re: U47 robbe tech rack
Post by: Silent Running on April 30, 2015, 01:13:35 am
Dose anybody know of a sure way to get the rear of the Robbe U-47 to fit snugly to the rest of the body? mine simply wont join up properly, i :-) can't complete it otherwise. Thanks.
Title: Re: U47 robbe tech rack
Post by: craggle on April 30, 2015, 08:16:20 am
Just another random question...

What size dive tank do you need for the U-47, Is it the 750ml one from Engel?
I have one of these in the loft nearing completion but then I changed my mind from the kit and wanted to make it a static diving sub and that's where it stopped.

Cheers

Craig.
Title: Re: U47 robbe tech rack
Post by: tsenecal on April 30, 2015, 10:55:40 pm
Dose anybody know of a sure way to get the rear of the Robbe U-47 to fit snugly to the rest of the body? mine simply wont join up properly, i :-) can't complete it otherwise. Thanks.




the best way to create a seamless connection between bow and stern sections is to glue two sheets of .040 abs to the edges of the existing abs "body", but perpendicular to the body...  with a hole cut in the middle for the WTC.   its kind of hard to describe, but i will post pictures this evening of mine, when i get home from work.   basically instead of having the rough edge of the existing body pieces you will have two sheets of abs butted against each other.
Title: Re: U47 robbe tech rack
Post by: tsenecal on April 30, 2015, 11:02:50 pm
Just another random question...

What size dive tank do you need for the U-47, Is it the 750ml one from Engel?
I have one of these in the loft nearing completion but then I changed my mind from the kit and wanted to make it a static diving sub and that's where it stopped.

Cheers

Craig.


i built mine with the 750ml tank, but in all honesty, a 800ml tank would work better... it was a struggle to make mine work with the 750ml
Title: Re: U47 robbe tech rack
Post by: craggle on May 01, 2015, 10:23:52 am
Many thanks for that, I'll have a look around for a tank 800ml or bigger then. :)

Would be good to get that back out the attic and progressed some more. I have the rivet kit, decks and resin conning tower from a German company that I think are no longer going. The conning tower is a model in itself.

Craig.
Title: Re: U47 robbe tech rack
Post by: Subculture on May 01, 2015, 11:34:33 am
Engel will make you a tank to a specified volume, always the same diameter however. They just vary the length.

Largest standard size is 825ml.

What you need to watch is the pressure building up inside the boat, as that can compromise hull seals if it gets too high.
Title: Re: U47 robbe tech rack
Post by: Silent Running on May 01, 2015, 11:34:25 pm
That's what I'm after thanks, any piccies of the boat in half by any chance please? btw what did you use to attach the two faces? Ta.
Title: Re: U47 robbe tech rack
Post by: Silent Running on May 01, 2015, 11:55:37 pm
Anyone know where I can get hold of this abs 0.04 sheeting? I'm in Herts. Ta.
Title: Re: U47 robbe tech rack
Post by: Subculture on May 02, 2015, 10:36:45 am
Easier to find metric sizes in the UK. 1mm being closest. To be honest any plastic sheet would do, just bond it in with modified acrylic. Ebay is a good place for small quantities of plastic sheet, try typing ABS plastic sheet.

Does tend to be more expensive than other plastics though.
Title: Re: U47 robbe tech rack
Post by: Silent Running on May 03, 2015, 12:25:57 am
That's what I'm gonna try mate, I've ordered a couple of sheets of abs A4, it's black but that doesn't matter, I can always go over it later. Ta everyone, and viva Nth London. ;)
Title: Re: U47 robbe tech rack
Post by: tsenecal on May 03, 2015, 01:43:07 am
Didn't mean to leave you guys hanging on this... two shots of the internals...  the two pieces on fore and aft that appear somewhat "white" are what i am talking about. as you can see, when the hull is closed, the two pieces of ABS lay against each other.    start by taking two sheets of styrene (i used .040, but anything will work) , cutting a 4" hole into them, so they slide over the internal WTC cylinder, and tape them together so there is zero space between them.   close the two pieces of the WTC together, and then either glue the rear external hull in place as the instructions indicate, or temporarily hold the rear in place so it doesn't move.  use plastic "weld" type glue to glue the sheets to the appropriate external hull parts.  after the two sheets have basically been solidly attached to the corresponding original skins, shave the two sheets down until they follow contour of the external hull.   putty and sand until the seam between the original hull and the new sheets is gone.


any more questions, ask, and i promise i will answer


metrically speaking, 1mm sheet would basically be the equivalent of .040"
Title: Re: U47 robbe tech rack
Post by: tsenecal on May 03, 2015, 01:50:04 am
as to the tank size....  its difficult to know exactly what the best size is...  like i said 750ml can be made to work, but it also has to do with the fact that there is a limited amount of space inside the cylinder.  much larger than the 750ml, and you also have to start looking at how much room is needed for the piston rod, and how far the tank has to be moved to make room for it.  I will post another pick of where and how i have the tank situated.
Title: Re: U47 robbe tech rack
Post by: tsenecal on May 03, 2015, 02:50:56 am
Okay,


two photos.

this is a custom built 1/8" acrylic addition to the original tech rack.  designed to allow for the addition of the tank, without all the leftovers for the lead acid batteries.   on the top, from rear to front: three servos, rear dive planes, rudder, front dive planes.  two 400 size graupner motors with 3:1 planetary gearboxes, motor speed controller, ballast tank.  in front of the ballast tank is space where the ballast tank controller and receiver were located.  on the bottom, from rear to front:  5 cell nimh battery, ballast tank, and room for 3 more 5 cell nimh batteries.   the battery packs were each 3000mah, giving me a total of 6v 12000mah for the battery.  speed controller fed the receiver.    for the specifics, the way it was setup, the rear of the ballast tank is 280mm from the inner edge of the rear endcap.  the plastic tube that you may see some of in the photos for the piston rod to go through ends 65mm from the inner edge of the rear endcap (the 1/2" white "line" running between the motors).   in all honesty, i think the ballast tank could be moved a little further forward, based on the amount of foam i had to put in the stern free flooding section.   maybe 20mm further forward.

the big white strips you see underneath the ballast tank are lead weights

the brass tube running along side the tank is an 8mm ID tube to feed the ballast tank.  it is in two pieces.  one is soldered to ballast tank, one is bonded to endcap.  the 1"+ piece of shrink tubing links the two together where the ballast tank motor is located.
Title: Re: U47 robbe tech rack
Post by: Silent Running on May 03, 2015, 09:56:31 pm
Is it a big job to convert to a pump system? How much are those 800 pumps? Would I need new batteries etc. to make space? I'd better get my boat wet first. :embarrassed:
Title: Re: U47 robbe tech rack
Post by: tsenecal on May 04, 2015, 12:15:13 am
Silent Running,

yes, it is a big deal to make the U47 a static diver.  due to space, the original batteries cannot be used, new batteries that fit in areas that were unused before must be made... why?  because the space where the original batteries go is where the tank goes.   to buy the engel 750ml tank and controller is going to cost about 220 euros. new batteries (in my design) were another 70 euros.  then all the time and work to make the changes to the tech rack