HMS MIMI 1915 by Ras Ambrioso - FINISHED - Scale 1:24 - Fast Motor Launch

[Ras Ambrioso]

Thanks Valeriy, you and Wefalk have been my inspiration to try and build super small pieces. Next, I plan to practice my soldering skills. All this brass work has been done using CA.

[KeithAug]

3 hours ago, Ras Ambrioso said:

All this brass work has been done using CA.

Ras - I quite often use a mixture of solder and CA on components. I start with soldering but when I think structures are too complicated or small to protect from the heat of further soldering I revert to CA. Take care not to heat up brass which has been joined using CA. The heating will break the bond.
Great job on the gun.

Edited January 30, 2023 by KeithAug

[mtaylor]

On 1/30/2023 at 3:38 PM, KeithAug said:

 Take care not to heat up brass which has been joined using CA. The heating will break the bond.
Great job on the gun.

And the fumes are not good for you or other living things either.

[Ras Ambrioso]

Thanks for the comments. I found out about mixing soldering with CA the hard way when I started an assembly and the whole thing broke up when I applied the heat. Soldering, and specially on small parts, is something that I need to practice. That is why I admire someone like Valeriy that can make it so clean.

[Roger Pellett]

A trick to protect already soldered joints from heat of nearby soldering is to use a Heat Sink.  This can be anything that will absorb heat without sticking to melted solder.  Aluminum is a good choice as it has excellent thermal conductivity and it will not fuse to ordinary solders.  Stainless steel on the other hand is a poor conductor of heat.

 

 I have been experimenting with another approach; using the latent heat of boiling water.  Although this may sound “high tech” it is nothing more than covering the area to be protected with a small piece of water saturated paper towel.  Heat from nearby soldering transferred to the wet paper heats the water which cannot get hotter than 212F until all of the water has boiled off.  In some cases, such as rungs of a ladder, the wet paper be twisted up and inserted.  This is easier than using a solid piece of metal.

 

Roger

[Ras Ambrioso]

Roger , I love your method. I am an engineer soaked in thermodynamics, thus your suggestion is to be done. 

I will be starting the big gun in Mimi pretty soon and should be able to test your method.

 

BTW, I have forgotten about three more pending items on Mimi: the jack staff, the bow mast and the siren. The siren will be interesting as it has a conical loudspeaker. I plan to heat a brass tube and expand it to the conical shape with a mandrel a little bigger project that my fire buckets on the Fifie.

This is what the finish horn should look:

 

Guys, thanks for following guys.

 

[Ras Ambrioso]

Th 3 pounder is on its way. I set up my 60 years old Unimat and had a few problems. The raw brass bar that I had for the build would not fit in the headstock opening and, when using the the 3 jaws chuck, the bar was too long, Fortunately I had the steady stand for this lathe . This allowed me to face the end of the bar and drill the centering hole.

After that, the barrel, five millimeters in diameter, fit through the headstock opening and I was able to face and center the fat part of the bar. The the biggest obstacle was to rotate the headstock in order to taper the barrel and the sleeve. The headstock refused to move. It was firmly fused together. Finally, with plenty of penetrating oil, it did and following is the result.

The overall length of the gun is about 102mm. The barrel taper is less than 0.5 degrees going from 5mm dia. to 4mm dia. Next comes the milling of the breech and the drilling for the trunnion.

 

[Joe100]

One of the most interesting theaters of the war in my opinion. It’s so interesting to see this project taking shape. I have a set of plans for Götzen, you’re inspiring me…

 

In my collection of nautical curiosities, I have an autographed photo of General Lettow-Vorbeck. I used to have a nap of the DOA signed by him, but sadly it was stolen while in transit to a museum loan. Another curiosity I have from the theater is a coin made from the brass salvaged from SMS Königsberg. These were made at the Tabora Emergency Mint, since coinage was impossible to import from Germany during the war. They had the devil’s own time keeping the economy afloat, and emergency coinage was the only solution. It’s in far better shape than most since it’s likely an early strike. 
 

Seeing someone else interested in this theater really gets the juices flowing!

 

 

[Ras Ambrioso]

Joe100, glad to hear from you. The Goetzen is a very nice subject with a great history; from its beginning as 5000 crates, to being armed, disarmed, scuttled and later raised to still be steaming as MV Liemba. It will make a great model but, for me, at 230 feet, it will be to large at 1/64 scale  which is the smallest scale I can manage on my details.

[Ras Ambrioso]

The work on the Hotchkiss continues. Today I managed to mill the the breech after spending a great amount of time installing a Sherfield milling attachment in my Unimat lathe. Note: I have the milling tower for the Unimat, but I was having difficulties separating the drive head from the lathe bed. After removing the tension screw the base refused to come loose. After I complete this model I will try penetrating oil. Fortunately, the head managed to turn the half a degree I needed to cut the the taper in the barrel. Any better ideas?

[Ras Ambrioso]

The QF gun progresses and I managed to mill the breech after 60 years since I had used a milling machine. A little touch up with a file will finish it good. The trunnion holes were drilled and the pieces for the recoil cylinders were attached.

Mind you that this gun has a really complicated recoil system and I will only be showing a simile. This happens to be my favorite artillery item and one day I may attempt to make a larger scale with more details.

The barrel sleeve and the recoil cylinders are joined together on a cradle and the whole assembly is lowered into the the carriage and secured from the top. I decided that was a little too much detail so I drilled the hole through.

 

 

Today I shaped the carriage and attached it to the base which, in turn, will be attached to the mount already on board. Very little is left for completion and by the end of the week HMS Mimi will be finished.

 

And, again, I repeat myself by stating that I could have not done this without you support, inspiration and sharing of the experience.

 

 

[KeithAug]

15 hours ago, Ras Ambrioso said:

The barrel sleeve and the recoil cylinders

Nice job thus far Ras.

[Ras Ambrioso]

The final touches. Following is the breech opening lever.

Then the shoulder rest. I fabricated  the channel section by sanding out one side of a brass square tube.

Then the gun assembly.

And the build is done. The following pictures are show the finished product:

FINISHED.

 

My next project is assembling a Protar kit in 1:9 scale of a Bianchi 1927 350cc racing motorcycle named the Freccia Celeste. This bike was driven by five times winner Tazio Nuvolari. The kit has a great history than my be followed in my build log at the Short Leave forum.

 

I want to thank all of you for your comments and likes that made this build possible.

 

 

 

 

[Keith Black]

Ras, congratulations on completing your great build. 

[Ras Ambrioso]

Thanks a lot Keith.

[ccoyle]

Great work, Ras!

[Ras Ambrioso]

Thanks Chris. I have not forgotten the card model (V108) thatI am going to make someday.

[KeithAug]

Ras, I was wondering how the gun could fire on the beam as the firing position would necessitate the gunner hanging over the side of the boat. So I looked back at plan which seemed to indicate that deck extensions were fitted on either beam. Was this the case and if so were they demounted and stored when the gun wasn’t in operation ? If so where were they stored.

[KeithAug]

Ah, I found the answer in the post by FrancisMcN earlier in your build. In his model the deck extensions seem to be hinged to fold up. Why did you decide to omit them on your build?

[mtaylor]

Beautiful model, Ras.

[GrandpaPhil]

Beautifully built!

Edited February 23, 2023 by GrandpaPhil

[Valeriy V]

Ras, congratulations on the completion of construction! 

I will be happy to observe how your skill improves with each subsequent work.

[FrancisMcN]

21 hours ago, KeithAug said:

Ras, I was wondering how the gun could fire on the beam as the firing position would necessitate the gunner hanging over the side of the boat. So I looked back at plan which seemed to indicate that deck extensions were fitted on either beam. Was this the case and if so were they demounted and stored when the gun wasn’t in operation ? If so where were they stored.

I came across a few pictures of the two boats at Lake Tanganyika preparing for action of which the attached clearly shows the deck extension partly folded on the foredeck of one of the boats.  I haven't seen anything in print to suggest that the extensions were removed and I would have thought that they would have been in place for at least the first action with the  Kingani and only removed after that if they had proved to be more of a hindrance overall.

[Ras Ambrioso]

Thanks all for likes and comments.

 

To Keith and Francis : I knew someone will ask about those sponsons on each side of the QF gun. They do show in the plans and were obviously in the design of the boat as the gun was expected to be trained about 120 degrees.  The 3 pounder had a very powerful recoil. When they tested the side firing, the gunner was thrown overboard and the boat listed as far as the gunnels.  The two victories, the capture of the Kingani and the sinking of the Heissman, were done on the chase by firing only forward and using their faster speed to overrun the enemy. The picture that Francis posted shows the gun trained sideways but, they are not firing it. These extensions were included in the kit from Deans Marine but I decided not to use them. Other interesting point about this gun is that the mount was shorter that normal and the gunner had to squat to fire. If you look at the side view of the model you will notice how big the gun is in comparison with the boat and the higher mount would have made the CG too high, increasing the rolling rate. Anyway, this is what is so good about this forum; how we can exchange our information.

I recommend the the book “Mimi and Toutou’s Big Adventure" By Giles Foden. I got mine at Amazon.

 

Again, thanks 

[KeithAug]

21 hours ago, Ras Ambrioso said:

The 3 pounder had a very powerful recoil. When they tested the side firing, the gunner was thrown overboard and the boat listed as far as the gunnels

Ras - Thank you for explaining. I was aware that in some photos the sponsons were not obvious. What you say about recoil makes a lot of sense.