Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Navy - Military - Battleships: => Topic started by: unbuiltnautilus on February 03, 2018, 08:31:39 am
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I have wanted to build one of the Royal Navy Brave Class FPBs for many years, the spark kind of evaporated when Brave Borderer was mass produced a few years ago. However, I had the opportunity to obtain a fellow club members Perkasa a couple of years ago. Last year I used it as a brushless testbed ( much useful data to follow! ), now it is time to convert to HMS Brave Swordsman, the under appreciated little sister of Brave Borderer. She was fitted with a modified superstructure, not as pretty as Brave Borderer, but an interesting prototype none the less.
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Work starts with the fitting of a smaller gas turbine duct on the rear superstructure. This well built part of the model needed removing, to give me a clear deck to rebuild from, out with the hammer!
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...and then back up again...
A hole cut in the deck is to help my rather annoying JJC Gas Turbine sound module to annoy the neighbours to its maximum effect. 1/32" ply is being used extensively to save a bit of weight.
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This 1/32" ply is a really nice material to work with. Smooth surface finish and easy to work with. Used with balsa square to stiffen up joints and structures, is resulting in a light but stiff superstructure. I need to save weight wherever possible, big heavy speaker going in at some point..
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Nice conversion, I agree with you I use 1/32 ply in all of my boats construction.
Will keep watching the progress :-))
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That is a good sized turret you have there as well! Are you using superglue to stick the parts with? I have a model that is partly made from thin ply and the joins keep splitting. It is an older model that I am restoring and wonder if the ply needs wiping or rubbing to remove any natural wood oils etc???
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Cheers for the responses chaps :-))
I am using a medium viscosity cyano in combination with a spray activator to kick off the joint. The balsa strips were pre-glued on one flat edge, slid into place quickly, then given a quick squirt of activator. The ply to balsa and ply to ply joints had a run of cyano chased along the joints with a cocktail stick, left for about thirty seconds to wick in properly, then zapped with the activator. The joint then cleaned up with either permagrit or a decent file.
I would doubt if your old ply is expelling some sort of oils, I would expect the opposite, with the ply being properly dried out, due to old age (!). The other suggestion, stick to big bottle cyano brands, rather than the cheap mini tubes. These seem to be troublesome, producing crystal laden joints on occasion. Other than that, I shall remain comfortably clueless on your problem!
Now, the big gun.....
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Regarding the big turret,I shall quote from a paper published by The Royal Institution of Naval Architects, Jan 7th 1960.
'The gun armament of coastal force craft had for many years been a combination of automatic weapons up to 40mm calibre and some larger guns such as the twelve pounder and 4.5" of greater hitting power, but doubtful accuracy when used from the poor gun platform provided by a fast moving boat in a seaway. After the war, attention was directed to the design of a gun, mounting and control system suitable for coastal forces from which the Coastal Forces System 2 ( C.F.S.2 ) was evolved. The gun used in the C.F.S.2 is a 3.3" calibre high velocity gun which, together with stability and prediction equipment, is carried in a turret mounting.'
' Trials of the prototype mounting on HMS Bold Pioneer demonstrated very high accuracy and rate of fire could be maintained even at high speed in a seaway. This considerable achievement brought its penalty in weight, power and complication. The weight of the mounting is 5 1/2 tons, while the all up weight, including ammunition, magazine fittings, and directing gear is 8 1/2 tons.'
Unfortunately for us modellers, the further development of this gun was abandoned. However, its size and weight penalties resulted in the gun position on the braves being relatively further aft than on other sister classes, such as the Perkasas. Resulting in the rather cool, 'go faster' look of the two Braves.
The drawings show the original layout of Brave Borderer, the optional variants that could be fitted to the basic design, and finally my attempt at overlaying Brave Swordsman over the original Brave Borderer drawings ( so take nothing on Swordsman as gospel, it is close enough to keep me happy, but has been the result of 'near enough' interpretations of the few photos of my chosen vessel..still, it gives an idea of the differences between these two sister vessels.
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The big turret was started last year, with the basic shape being a combination of 3/16" ply for the base and 3/16" and 1/4" balsa sheet for the sides. Now is the time for 1/32" ply skins to be applied.
As before, medium viscosity Cyano glue was used throughout. Cyano on the balsa, while activator was pre-sprayed on the plywood. This meant getting it right first time, no room for errors or it would be scrap! Luckily all ( almost all! ) went fine. The slots for the gun were cut in the ply first, the sanded with a drum sander in a hobby drill to get the top and bottom curves.
Once everything was glued on, I began hacking the balsa inner cores away from the slots. Using the hobby drill again with a combination of Permagrit and sanding drums, much mess was made. Kept the sawdust in a tub for filler powder later on in the build.
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The gun and breech were a mix of a 1/35 scale Tiger tank turned aluminium barrel which I had already, and a single piece of teak, chopped to match the only photo I had of the turret. A bit of plasticard added to the look of the breech mechanism and should look good once painted grey.
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THEN I found another photo of the turret, which I already had, but didn't seek out cos I forgot I had it....so a bit more detailing work will be in order %)
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Final job, bringing us up to yesterday evening, was infills in the deck hatch that would otherwise be big holes when the new, slightly smaller superstructure goes on. This time using 1/8" ply, cut to a tight fit, then filled and blended in to the existing deck
So far so good. The old superstructure will no longer fit now, therefore no turning back....Looks fast standing still!
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This time using 1/8" ply, cut to a tight fit, then filled and blended in to the existing deck
...and you have made a fine job of this too!
This is a fascinating refurb and refit - keep it up, you're doing great. :-))
Regards,
Ray.
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Not much doing today. Too busy at B&Q purchasing upholstery nails ( Steampunk demands their use for rivets!! ). So I finished of sanding the filler flat first. I used Deluxe Materials Perfect Plastic Putty for this. I was unsure of this product at first, and still wont use it on the hull, but above deck, and suitably Sanding Sealered, should be fine. It spreads out easily with spatula or offcut of plywood. Drying time is slower than a two part filler, but patience is my middle name....
1/8" x 3/8" spruce coamings have replaced all the originals round the modified front hatch, thereby restoring the splashproofing up front..followed by me hacking the coamings off the rear hatch, ruining all those good intentions! The Braves did not have the slightly raised centre deck running all the way aft like the Perkasa. Instead, the deck was flush aft of the ducting. So a suitable piece of !/8" birch ply is now cut to fit. All I have to ponder is how to make it removable for rudder and servo access if needed, while keeping the water out. A Job for tomorrow I think..
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Is this a 1/32 Brave? I was curious as to which outrunner you were using.
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UBN....following on with interest :-)) ....& as you say, this is not a true scale conversion.......
These scale vessels even at scale speed can produce a stern wave much higher than the stern.......so <*<....a complete stop of engines could awash the stern
So you could consider taking Refit Builders Licence O0 & elevate the stern Quarter Deck by continuing the 1/8 x 3/8" combing to cover this area.....all of your original images depict this with the elevated plinth & the 40/60 Bofor mount at the stern
This would certainly assist in a water proofed stern
Derek
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UBN....following on with interest :-)) ....& as you say, this is not a true scale conversion.......
These scale vessels even at scale speed can produce a stern wave much higher than the stern.......so <*< ....a complete stop of engines could awash the stern
So you could consider taking Refit Builders Licence O0 & elevate the stern Quarter Deck by continuing the 1/8 x 3/8" combing to cover this area.....all of your original images depict this with the elevated plinth & the 40/60 Bofor mount at the stern
This would certainly assist in a water proofed stern
Derek
I had to renew my Refit Builders Licence earlier this year, it had got a bit dog eared! The good news, following extensive trials last year, driving it like I stole it, did not result in the stern wash problem. It did highlight the 'sidewash' problem, as visible in the first photos at the top of the post. This created some water on deck issues. If I just piloted the vessel in a responsible manner, this would not happen, where is the fun in that!
Anyway, walnut 'D' section is going round the hull/deck edge to improve the looks and hopefully divert some of the side spray away.
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Is this a 1/32 Brave? I was curious as to which outrunner you were using.
Yup, this is the 1/32 model. I have carried out a series of brushless trials with the model, using two different motors and a variety of prop sizes and voltages. With a watt meter in line, I have actual data, which I shall share soon ( When I find the notebook! ).
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This is becoming a gem UBN. The use of a tank gun barrel is ever so logical and saves loads of time whittling or machining as well.
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Guess what, the NEW superstructure will not fit! So, more mods required.
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this is a nice conversion / build, been joy to read and look at the photos :-)) thank you for sharing.
i just managed to get hold of a type 45 destroyer last week and she sailed for first time with me yesterday its nice to get back into navy boats / ships
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this is a nice conversion / build, been joy to read and look at the photos :-)) thank you for sharing.
i just managed to get hold of a type 45 destroyer last week and she sailed for first time with me yesterday its nice to get back into navy boats / ships
Thank you, much more to follow as always.
What Type 45 have you got 1/96 or 1/72 ( or 1/32! )?
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A bit of CAD for the next part of the build, Cardboard Aided Design!
With the different superstructure profile of Swordsman, there are no plans existing, showing the layout from the top, sides or front/rear. I have estimated a side view but have had to 'learn the ship' to aid me with designing the intakes protective cowling. The photos can be contradictory at best, regarding angles and the like. The best I have been able to do up till now is use Brave Borderers design as a guide to Brave Swordsmans design.
It seems fair to assume that the layout of the two hull structures are the same. The flying bridge seems to be in the same place, and the big intake cowl is in the same place. These all help to anchor the unknown parts of the design. The big front cowl serves a specific purpose, this is to ensure sea water spray is deflected away from the engine intake cowling, over the three Proteus gas turbines at the aft end of the ship. Brave Borderer displays something of a streamlined aerofoil profile. To carry that through to the shorter profiled cowl on Swordsman, could be as simple as angling the cowl down slightly, towards the aft end. Drawings of Brave Borderer indicate that this cowl also tapers aft, when viewed from above. All I need to do is incorporate all that into a pre-existing model...easy.
Incidentally, the difference between the two sister ships is never commented on, but it seems more than likely it was a trial between two designs of cowlings. The more sexy curved cowling seemed to have won out, as it appeared in all the following variants of these designs. However, the less attractive squared off cowl design did appear in the Swedish Spica 1 missile boats in the mid sixties.
Anyway, less chat, more cardboard.....
Starting with the obvious and easy end, I mocked up the forward bridge structure, first just taped together, but then hot glued for a bit more strength.
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The main reason for all this 'CAD' is to get the interior structure worked out in my head. For some reason I have had a total mental block on this one. Usually I can 'see' what the interior structure etc, needs to be before building...not this time though. Therefore, the cardboard is a good substitute for thinking about stuff!
The aft cowl and doorways into the structure were next. One plus of doing this, is being able to argue that the bulkhead position usually modelled in this type of model, is too far aft. The whole reason for all these curved bits on the Vosper FPBs, was to allow the vast amounts of air needed by three gas turbines, to be safely sucked into the engines, without sucking in half of the English Channel at the same time ( also somewhere to scoff a sly sandwich, sheltered from the elements apparently! ). If the bulkhead was modelled where it normally was, this would severely restrict any ability to suck air. What it does do is make the structure easier to assemble. Leave it out and the whole thing gets more complicated to build...which is fun!
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The weird shaped part that fits flat on the hatch will probably be the first part I build. Attaching and assembling up and forwards from that part. This has made the whole exercise worth it, as this was what I could not visualise with just coffee and doughnuts alone!
The final task was shaping and fitting the top structure, followed by standing back and comparing to old photos and video. So far I am happy, but boy is it ugly!!
Motors next :-))
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i have 1:92nd but its modify hull but she good on the water
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She's looking great. I did a bit of searching and I think the gun is a 'Navalised' 20 pounder originating from the gun the Centuron carried before the 105mm gun came along. The Tiger tank barrel looks the part especially with the muzzle ring :-))
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Glad I saved it for that 'future' project!
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Yes looking good build-up UBN O0 & that's a rather formable vessel with the 40/60 Bofor mount to compliment on the stern ..... Derek
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Performance data finally compiled, much less than I expected as I discounted props that proved too slow, produced too high a current drain, or were operating at a very low voltage. Although the 4.8v/6v range provided some interesting results that would suit smaller, fast but not as fast, vessels. With very good low current performance. Proving that down there 'in the dirt' as I described it, currents and performance still have uses, just not on this speed machine!
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I hope everyone can open the doc attached. Anyway, I have bucked the REVS REVS REVS + VOLTS school of brushless motor operation, and got the performance I want at only 8.4v. The only problem I have now, is that I am tied to NiMh batteries for this voltage. I will try the model on a 7.4v LiPo at some point. I am hoping that the 1 volt drop in voltage may just be mitigated by the slight reduction in weight, and the extra grunt offered by Lipos...well you can but hope!
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Like my HMS Snowflake and SS Ohio builds, I decided to knock up some resin fittings for the model. Mainly driven by a need for four identical long range tanks, plus we have another conversion within the club, being produced as a Libyan Navy variant with SS11/SS12 Surface to Surface missile fit. This model also needs four long range tanks. Add to this the 40mm Ammunition Lockers, five on mine and ten on the other model..decision made, get moulding!
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I am most chuffed with the gas turbine exhaust doors. The master started life as some unused resin in the bottom of a shot glass!
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Today I got some plywood construction under my belt. The forward bridge work today was mainly in 1/16" or 1.5mm ply. I have gone up a thickness for this part of the build mainly for structural strength. Initially it was only going to be two pieces in 1.5mm, with the rest being constructed out of 0.8mm as before. Unfortunately, the structure started to twist as I assembled it. Mostly caused by slightly less than flat plywood, introducing stresses as I went. So 1.5mm ply was used instead, as I used every sneaky trick in the book to get rid of the twist.
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Most of the re-enforcing is going in AFTER the parts are tack glued together. Cyano gives me an almost instant stick, and is strong enough to allow me to pick up the assembled part, check everything is aligned properly, then beef up with balsa strip or plywood as needed.
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I am working my way towards the cowling assembly. Not looking forward to it though! Many curves and not much structural support. So I am building such and such a part, while thinking three or four steps ahead to the curvey bits! I have to work like this as at present, I only have a vague idea how I am going to approach this part of the build.
That's Scratchbuilding :} :} :-))
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I am once again at that point of the build. Construction has caught up with planning....best option, cup of coffee and a night in front of the TV!!
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Can I ask what you use as a sealer for the plywood? Dope or sanding sealer or something else?
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Can I ask what you use as a sealer for the plywood? Dope or sanding sealer or something else?
I usually use Cellulose Sanding Sealer, sometimes I use Shellac Sanding Sealer instead, just cos I have some..also it has a slower drying time, which can be useful for wicking in to softer timbers. Usually at least two quick coats, followed by a dry sand with wet and dry paper. Then a primer coat or filler as needed.
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Back to my brushless current tests. For those that have a bit of trouble opening PDF documents, I have figured out how to cheat the PDF, so I can display it.
There is not a huge amount of data there, but what is there gives an idea of how quickly the current can ramp up as the voltage rises. The 2 blade 45mm prop that I settled on was, to say the least, unexpected. I was anticipating something at least 10mm smaller diameter as the best match. However, that is why we test things!
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Excellent working out Dr Nautilus :-)
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Excellent working out Dr Nautilus :-)
Dr Nautilus?? Yes, I can live with that :-))
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ubn.....I am having trouble in understanding what Class of [Fwd] gun mount you are using %)....[not the Bofor down aft].... Derek
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ubn.....I am having trouble in understanding what Class of [Fwd] gun mount you are using %) ....[not the Bofor down aft].... Derek
Evening, or whatever classes as evening on the other side of the world!
I shall refer you to reply 7 back on page one, where I detail the intended armament fit for the Brave class, and what went wrong, leaving us with Bofors fore and aft.
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Right ho, construction has once again commenced, following brain cells catching up with build requirements!
First job was to build an aft extension, to support the projecting cowl assembly. This was sanded slightly to give a subtle down angle aft. Made from two layers of balsa wood sheet, it was then rounded off to match what was already there.
Also, I decided to run some 3/16" square balsa beads around the gap in the top of the superstructure. All useful for a good glueing surface when it comes to bonding down the roof.
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The next part of the cowl assembly was the 1/32" ply top. This was initially going to be a one piece, wraparound, that would consist of the side walls and streamlined parts disappearing into the door area...just that bit too ambitious on reflection :o . So, roof with slight fold downs at the sides, plus a slight angle change about an inch aft of the front edge. Scoring the wood ( on the right side!! ) is very helpful for this construction. Allowing me to fold the ply over the existing balsawood shaped formers. Cyano and activator allowing me to build fast, while on occasion, glueing myself to the plywood!
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A bit more CAD was needed, so a Cardboard shape Aided my Design. Due to some sort of structural miracle, it could be recycled for a template for the other side of the superstructure with the absolute minimum of adjustment. Wonders never cease...
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Then things got intense and much plywood was cut to fit, while not many, if any, photos were taken. I must have been enjoying the build process too much.
Repeating the process of scoring and folding, 1/32" ply slivers were bonded in the gaps between the flat panels. These took up the space better than filler alone would do. Re-enforced with cyano glue and zapped with activator, they were then ready for sanding. I use a flat Permagrit file for this work. making sure not to sand straight through the plywood!
Once sanded to a decent profile, the whole lot was then fillered with a one part, air drying filler and left to go hard.
Once sanded down, a handy comparison with the original cardboard mock up was in order.
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The cowl was the part causing me sleepless nights ( Almost ), with that out of the way, mostly, it should be plain sailing from now on in. Offering up the now mostly complete superstructure to the rest of the model, I can see why most people build Brave Borderer, not Brave Swordsman, Swordsman is butt ugly! Still, it should grow on me as the upper works get more 'busy'.
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It just looks a little more archaic. I would rather have that 20pounder up front to make someone's day a misery any day!
She looks a little cutie UBN :-)) :-))
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She is indeed a little cutie, I look forward to blasting round the lake with my old JJC Proteus Gas Turbine sound unit upsetting the locals %)
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Small problem..the forward superstructure is 1/8" off centre. I was aware of the issue with the old superstructure and thought I could fudge it. It has become very noticeable..to me anyway...since marrying the two parts together. The big problem, I built the superstructure tight on the current flange, so moving the whole thing sideways 1/8", while still retaining a tight fit, will be a bit of a job. So have been sidetracked onto a quickie project over the last couple of weeks................
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There's no harm in that, it gives you time to relax and think about how to do it, or just to gird your loins for a possible horrid job of adjusting and repair. It's good that your club has workspace, that is a dream arrangement for me :}
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Well, we are not quite working there yet. Still at the final stages of preparing the middle bit of the building ( workshop ), and getting to know our new neighbours. Still our first open day was a rip roaring success, so onward and upward!!
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Hi unbuiltnautilus
I bought an unstarted Precedent Perkasa kit 49 and 1/2 inch kit today, so I will be checking on our post.
No drive line, rudder, anchor, railings but the vac torpedos are in the box with the booklet and side and top view plan.
I like you CAD work I use the same idea with Manilla folder.
Very handy for getting boat frames the same on both sides.
Canabus
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You cannot beat old school CAD! Good luck with the model. Keep it light and it may well run with a twin version of my single shaft set up.
I do prefer the bigger version of Perkasa, but practicality got the better of me ( for once!! ) and I opted for a club members 37" model for the project.