Topic: Updates on the 70`CMB (Read 9375 times)

White Ensign · « **on:** May 17, 2006, 10:37:00 am »

Is anybody interested about updates on the 70`CMB or on a report how and why it was made?

Happy modeling!

J?rg

flag-d · « **Reply #1 on:** May 19, 2006, 11:47:55 pm »

Yes, very. I came across these when I was researching for my Fairmile type D. They look an interesting model. Love to see some details.

Mike

splash · « **Reply #2 on:** May 21, 2006, 03:42:49 pm »

Come on then !

Post some updates please. :)

boatmanic942 · « **Reply #3 on:** May 21, 2006, 08:22:21 pm »

would like some piccys

White Ensign · « **Reply #4 on:** May 22, 2006, 09:16:40 pm »

O.K then..... the very first step looked like this. We had been sure that we wanted to make two hulls, so we decided to make a pattern and mould it in fibreglass. Depending on the shape of the hull the pattern needed to be split.

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White Ensign · « **Reply #5 on:** May 22, 2006, 09:29:27 pm »

... grind and glue is not my favourite job at modeling, but somebody has to do it....

in the second photograph you can see the upper half of the hull on the left side and the pattern on the left. Very important by doing the PNP-method is, that your origin ist stable, coated with fibreglass and painted with Acrylic and gloss colour. This will give a perfect finish and a smooth surface.

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White Ensign · « **Reply #6 on:** May 23, 2006, 08:51:01 pm »

Though, as it was a two-part pattern one has made the lower section with all the power unit and the rudders, the other one cared about the decks-section with the "superstructure", engine-room hatches and mine-troughs. All these items had been made out of 0,2mm brass.
... to be continued (if you please)

White Ensign · « **Reply #7 on:** May 23, 2006, 09:06:58 pm »

... and the upper form with the superstructure!

White Ensign · « **Reply #8 on:** May 23, 2006, 09:11:17 pm »

... the motors had been Graupner Speed 600 BB Turbo, watercooled running on a 44cm long shaft 4mm dia.....

(Next update tomorrow...)

White Ensign · « **Reply #9 on:** May 24, 2006, 10:50:48 pm »

Now I want to come up with the next update (I hope it does not become boring)

Then we found that the lines on the lower body needed some protection and strength. Though we decided to add some L-shaped brass profiles with 2- component Epoxy mould.

White Ensign · « **Reply #10 on:** May 24, 2006, 10:54:25 pm »

The same we did on the sides. From a specialist of the fast-electrics section we had been told, that it will improve it`s appearance as well, as the water will run away from the hull and not come up and give more resistance.

White Ensign · « **Reply #11 on:** May 24, 2006, 10:58:35 pm »

Then we made a short trial, both bodies had been taped together and we checked out the functions. We found the 10 cells seem to promise the best performance and though the bodies had been fixed. With a small brassplate inside, which runs around the hull and also Epoxy glue.

Daryl · « **Reply #12 on:** May 25, 2006, 08:57:14 am »

look forward to the next update, keep up the good work.

Daryl

White Ensign · « **Reply #13 on:** May 25, 2006, 09:00:40 pm »

Hi Daryl, thankyou for the nice compliment

The next point was, that we found the steering-system has to keep lots of power. How to make the rudder-carriers? As they have to keep the shaft in their ends as well they need to be very solid, but we wanted to keep the shape of the origin. The triangle-shaped carrier itself to mill out of a block was the hell of a job, but we need to make 4 of them. And all 4 had to be identical. The final decision was a special tool I have created, in which it was possible to produce absolut identical items.

White Ensign · « **Reply #14 on:** May 25, 2006, 09:07:09 pm »

In this form it was possible to solder the single items together, which was easier than milling them out of one block.
The rudder-blades had been made out of 1,5mm brass. Like the origin we had made the steering from the servo just to one rudder, the second one will be moved by a rod. This "Master/Slave" system works well. The connection from the servo to the rudder is a 1,0mm steel-rope. It has enough flexibilty to move with the joints of the rudder and is strong enough to bring the power for the movement.

White Ensign · « **Reply #15 on:** May 27, 2006, 10:39:16 am »

Hello to all modelers and shiplovers- now I want to go on with my update.

As there is just a very small space left on these boats to get some possibility for "service" we decided to fix the mine-trough in a brass-frame and fix it with silicone out of a tube. As this part of the boat will be surely a very wet area (later we found the whole boat is wet!)

White Ensign · « **Reply #16 on:** May 27, 2006, 10:43:09 am »

... the same way we went on with the superstructure and the engineroom hatches. The trouble was, that we needed in that part of the boat acceptance to the Nicads and in case of the superstructure to the r/c components. Though we tried to seal the frames also with silicone, being aware that they will never seal it completely.
The shape and the raw dimensions of the superstructure had been given by the drawing- but just a raw imagination. Though we ordered some available photographs from the NMM and took the position and the dimensions of details out of the photographs.

White Ensign · « **Reply #17 on:** May 27, 2006, 10:45:50 am »

As all the other items, they had been made out of 0,2mm brassplate and soldered. The hell of a job and it took us three tries to get them properly doner.
(to be continued)

ron h · « **Reply #18 on:** May 27, 2006, 11:10:52 am »

Some verynice work there, very interesting.

Daryl · « **Reply #19 on:** May 27, 2006, 11:45:26 am »

Great thread a very interesting build, I hope you are going to post more builds after the CMB thread as they are very interesting.

May I ask how you got on with the NMM, I found them very helpful but if you want several plans,photos etc the total cost soon mounts up. Its a pity they don't reduce their prices for modelers.

must get on with the P-boat soon, sam and I are off to Weymouth show in July and are attending a show in Thornbury in August, ideal to stock up on modeling supplies.

Keep up the postings

Daryl

White Ensign · « **Reply #20 on:** May 27, 2006, 12:56:59 pm »

Daryl, to be honest- I`ve found the lads from the NMM very helpfull, but from the 4 photographs I have order just three belong to the 70`CMB, one was very matching to a 55`or 40`type. The prices anyway are...... tremendous, compared with photographs which can be ordered from a museum in Germany. But the photographs, together with the drawing (which was a better sketch) had been very helpfull to catch her appearance in an early stage anyway.
If anybody is interested, I will come up step by step with my flottila as there is HMS Lord Nelson, HMS Velox, HMS P-Boat, HMS Mohawk (but to be honest not very interesting).

About your P-Boat, you can calculate (if all items like motors, shafts, props are there) about 6 weeks until it is finished.
One tip for the funnel and the superstructure: Leave all plasticard away! It is definately too heavy! I have used 0,3mm aluminium-plate f?r the superstructure and the funnel was made out of paper, soaked with superglue. Very lightweighted and solid!

J?rg

Daryl · « **Reply #21 on:** May 27, 2006, 04:48:32 pm »

Thanks for the tip about the plasticard, I'll bear it in mind as thats what we were going to use. I'll look forward to the P-Boat build so I can pick up some tips.

I too found the NMM very helpful but as you found expensive when you compare their prices to other sorces. Back to the CMB have you got independant control over the motors? to help turning.

Very best regards
Daryl

White Ensign · « **Reply #22 on:** May 27, 2006, 06:40:41 pm »

Daryl, it was not necessary to install two speed-controllers as their "support" in a turn would not make much of a difference. The props are tree-blades, with an diameter of 35mm- and are just 45mm appart from each other (measured midth-midth).

Like the origins these boats have not been build for doing manoevres, they had to wear a weapon from A to B- as fast as possible. Though we decided to limitate the rudder on 35 degrees- for not risking any danger. Although it would lead to problems in the steering-system as well.

After all the implantation of the technics the next step was to install all the footrails and side-protections. The footrails had been made out of 1x1mm L-shaped brass-profiles, the side-protectors out of 4x2mm plasticard. All had been glued with Epoxy-glue on the hull and had been fixed with small bolts of brass.
Then we sprayed the hulls with a primer (no filler, as he would increase the weight) and bumps and dents had been filled with a leightweigth-mould. You may start to smile, but even 250 grms. of additional filler will be about 10% of total weight. And we had been sure that with a total weight of 2,7 Kilogrms. there will be no more extras possible. Our goal was to save weight everywhere, to put it in the capacity of the installed cells.

White Ensign · « **Reply #23 on:** May 27, 2006, 06:48:07 pm »

Also we made some other fittings, like the covers for the hatches on the bow. A wooden ball was taken and it`s diameter was was cuted out a woodplate. A piece of plasticard was layed on it and heated up with a hairdryer. As soon as you find the plasticard becoming weak, just pull it over the ball. Now you have a half-ball. Cut it in the midth and you`ll have exactly the covers you need. The had been glued on the deck before the final paint was sprayed on.

(To be continued)

White Ensign · « **Reply #24 on:** May 31, 2006, 09:42:15 pm »

After all the planing we came to the point of guessing. The plan don`t have shown details of the "bridge", we just had two photographs where we had a small guess about it`s measures and shape inside. So we tried out to make the best of it and build the "superstructure like that.

News:

Author Topic: Updates on the 70`CMB (Read 9375 times)

flag-d

splash

Daryl

ron h

Daryl

Daryl