Revell 1/72nd Type VII U-Boat.

**Bunkerbarge** · 08-02-2006

Well I fancied a bit of a break from gluing bits of wood together on the bridge of the Ben Ain so I went out and got myself a kit that I have fancied ever since it came out and that is the Revel 1/72nd U-Boat. I also fancied a bit of plastic modelling, which I have not done now for a long time.

A superb kit in its own right but my imagination was fired up with the March 2005 issue of Model Boats magazine where they motorised one as a surface running model. I was actually involved at one point with buying that very model but the guy backed out at the last minute which was the final push I neded to get my own. Since then they have also run an article showing a dynamic diving version but, for this to work, the model has to be ballasted to the deck level so no-one ever gets to see so much of the boat when it is in the water. I wanted a surface running boat at its normal de-ballasted water line.

I also wanted to improve the basic kit as much as possible so I purchased a lazer cut wooden deck set for it and a brass PE set from White Ensign models. Both these items arrived the very next day so off I trot to buy the model from my local model shop.

The wooden deck is superb but to get the best out of it the steel deck ends should be cut from the original plastic deck. This requires a bit of care and attention but the effect is well worthwhile. I have also arranged the RC components to ensure that the minimum amount of deck requires removal which means the shafts are a lot longer than the arrangement in the magazine but my model will require only the centre section to be removable and the aft steel section. This is a big improvement on the magazine kit which had two additional hatches cut in the deck.

I will post a few pictures of the construction later so that members can see how I have converted this kit to a working RC model.

Nigel.D · 08-02-2006

Richard I have also got this kit along with the pe parts i was debating on the gun and torp loading set as well? I havent started mine yet. Also whats the quality of the laser cut decking i saw the pics but couldnt make my mind up as my Amati u47 has p.e decking which is really good but was a pain to fit.

**Bunkerbarge** · 08-02-2006

The wood deck is a vast improvement over the plastic original. It fits well, has better detail and looks superb. When used with the original plastic steel deck ends the effect is very realistic. I am not going to bother with any of the other detail sets as they are very much more diorama orientated and not suitable for a working model.

One main advantage for me is that I will varnish it with matt clear, then overcoat it with matt black, as per Kriegsmarine practise, then I will scuff it away carefully with wire wool. This will let the wood show through and I am hoping will look very effectively weathered.

I'll do some pictures later.

**Bunkerbarge** · 08-02-2006

Just a couple of pictures showing the progress of the Sub. The wooden deck is not going to be fitted until the ballast has been secured and the back of the deck requires sealing off to prevent the ingress of water. I think I am going to use varnished brown paper for that.

On the second picture you can see the brass rudder bushes fitted with araldite which are a nice sliding fit on the brass tube used for the rudder posts.

Nigel.D · 08-02-2006

It looks as good as pe i think il have to invest in one now (god more expense the mrs will rue the day i came on here lol)
i think a visit to thorntons may be in order as well

Mankster · 08-02-2006

Be careful how you seal that nice deck from the water.

**Bunkerbarge** · 15-02-2006

As with so many of these bright ideas it has taken quite a bit longer than was anticipated to do this model.

I have now manufactured a base to mount the two motors and steering servo inside the centre section of the sub. I have installed an additional bulkhead to seal off the radio compartment at the aft end, just in case, and I now have the basics of the running gear installed.

I used brass shaft tubes for the 2mm steel shafts and aircraft control wires for the rudder servo linkages. I added supports for the servo wires and made a lead in to ensure the piano wire enters the rudder horns at the correct height.

All in all it is coming along nicely but, as I said, is taking a lot of time to do. I am now turning my attention to the rest of the electrical installation before getting the underside painted and the rest of the model completed. I have hacked around an aircraft battery to make a 7.2 V Ni-Cad pack which should assist will ballasting nicely and give plenty of run time for the two small motors.

I am extreemly pleased with the wooden deck set and the PE set from White Ensign models which have all fitted perfectly and have made a vast improvement on the stock kit.

Ballast is going to be a total of about 12-1300 grams minus the radio gear and running gear so I am anticipating requiring about 900 grams of lead sheet in the bottom of the model.

**Bunkerbarge** · 24-02-2006

Well the sub has progressed nicely but, as always, has taken a lot more time than was anticipated.

I now have all the workings installed and tested after a lot of messing around and fiddling. I wanted to make sure that the deck had the minimum of openings so I have arranged for one main access through the deck in way of the centre section around the tower. Either end of the deck I am going to glue in place with the far aft steel section being the only other removable piece to allow access to the rudders.

This required the motors to be in the centre section and so the tubes were 10" long with 12" long shafts. As these were 4mm tubes with 2mm shafts the fit had to be spot on as any slight misalignment would cause interference. I also checked with the shaft manufacturer what lubrication I should use and he assured me that silicone grease would do the job. I had asked as I was concerned that such small shafts, so long and connected to very small motors might be a bit of a struggle.

As it happens I was correct and after installing the shafts and filling one with grease I discovered there was no way the motor was going to turn it. So all the grease had to be removed, remember pipe cleaners?, and I retried with light oil. It worked fine but leaked from the end so I realised I needed an oiling tube and grease on the bearings.

The pictures show the set up as it became with two oiler tubes fitted to the shafts, not easy after they were installed, and the motor and coupling set up. The motors are mounted in a piece of wood, drilled with two 16mm holes on 31mm centres then cut in half to form a clamp. This holds the motors nicely and the only concern I am left with is the very poor quality couplings which are so far out of balance as to cause vibration. They will be replaced in the future but will do for now.

The rest of the installation includes a micro receiver from Hightec, a nice solid state 1 amp speed controller with switch and a battery pack made from one of my old 9.6 volt aircraft packs. I removed two of the cells to make a 7.2 volt pack which fit very nicely in the front of the boat.

All this lot was installed in a tray manufactured from plasticard on the workbench, before fitting into the hull.

Ballast was made from lead sheet cut into thin strips, which fit into the keel very neatly and wider lead strips laid over the top of those. All the ballast was secured in place by pouring resin over the top of it in stages to reduce the heat build up when curing.

The pictures show the various components as fitted in the tray and after the final sea trials in the domestic test tank.

The hull has been sprayed with Tamiya acrylic spray tins which proved to give a superb finish. The only problem seems to be that there is not a great deal in each tin, which very nearly caught me out. The dark grey has had three coats and the tin was empty when I finished. I hope I will have enough of the lighter grey for the tower and deck fittings and I have a pot of very dark grey for the decks.

Now all I have to do is finish the model!

**Bunkerbarge** · 26-02-2006

Well I have now had a go at the first two deck pieces and I have to admit to being quite pleased so far with the results.

First I glued strip wood to the underside of the deck to give it strength and to seal the holes against the ingress of water. I then gave it a coat of satin yacht varnish top and bottom making sure that the coat on top of the deck remained quite thin to prevent hiding the detail.

When that had dried I gave the upper side of the deck a coat of Tamiya acrylic German Grey, once again making sure that the detail wasn't covered. The weathering will be done later when I bring out the detail with some shadows, scuff some of the grey away to reveal the bare wood underneath and add salt efects with some pigments. This will then be coated with a final covering of sprayed matt varnish.

The two deck pieces will be glued onto the hull next leaving the centre section with tower, deck gun, railings and hatches as removable to enable access to the RC gear.

magpie · 27-02-2006

Looks great!!! I like the details in the tower area!! Very good looking boat.
Jason