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There are a couple more struts to add to the movable part and hopefully the skins will stiffen everything up how ever I've not yet decided if the skins need to be stronger than the supplied ply ones As for the electrical supply, tests to be carried out on multi plug connector but this depends on how many lights I have and if I want them independent of each other or I could use the lifting arm as they are brass and could be wired neatly at each pivot plate however this would only supply a common + and - supply, we will see.
Hi there, Patience is a virtue, of which you appear to have a lot. AS for your slight "blooming /blushing my only answer is (raining or exceptionally cold or humid weather which often occurs when rapid evaporation of solvent cools the air over the coating below the dew point.) (internet is brilliant) however you've set me thinking now as as you will have seen in my blog having got the roof mechanism working I have yet to apply the skins. I appreciate any thoughts on - 1 Using existing skins? 2 Using existing skins and then f/glass and cloth both sides? 3 I have a quantity of mahogany veneer 0.5mm from memory, three sheets cross grain and glue whilst the held in the compound curve? 4 use thicker ply?
As I mentioned in a previous post I want to put some detail into the cabin and in order to do this I wanted the roof to open so that the detail can be seen and also giving good access for construction and detailing. So I looked at various lifting lever systems and the one which gave greatest access and took minimal room was a simple parallel bar mechanism. I first made a card model to ensure it worked before investing a lot of work in making the real thing. I used some brass plate cut into 3 x 2mm strips and using 10BA fastenings I constructed the levers and securing plates. Before fitting the mechanism and cutting any roof trusses I tried the mechanism using the brass bars and a card roof replica to once again prove its operation. I then added further cross beams to ensure the roof frame stays stable when the roof is lifted and that the roof skins had sufficient support when closed. All through this design and make session the cabin frame was only secured by temporary pins and had and no roof skins fitted, this enabled it to be lifted off in one piece whilst working on the frame. Now the mechanism works the cabin detail can be finished before finally fitting the roof skins.
It will be a working model and the power details are to follow. (don't want to give you too much at a time) the area between BH 3 and 4 will house the motor, ECS fuse box etc. I may detail the "Sick Bay" which is between B2 and B3 and batteries will be in the area BH 4 and 5 and of coarse the area that houses the hoses etc in the stern will be detailed.
Thanks for the pictures, very helpful I'm working on the three panels now but something so small takes more time than building the main structure of the boat, however I do enjoy all aspects of the build and hopefully this idea will work out
The next piece is what I can only describe as the dash board (what’s the nautical term?) Bridge? Anyway it’s the bit with all the knobs and levers that make it go. I chose to stick with ply construction throughout the build so will be using 1mm 3 ply. I copied all the dimensions from a cross section detail of the cabin instruments and controls and then made card models first to ensure everything fitted. I made spaces for the speed control and compass and drawn up detailed drgs of the instruments which I hope to make from 0.5mm stainless steel with back lighting of the dials and general lighting from LEDs. The cabin area will finish at the door to the galley kitchen.
I wanted to try and recreate the detail as per the available photos and drawings that I had so the first thing was to try and make the cabin have walls and a door, so previously I had cut away bulkhead B2 and extended CF2 to the bottom skin and put the door opening in. Now for the actual piece of cabin floor, the entry is slightly strange as there appears to be an inset step from the from the sick bay up into the cockpit but then it is relatively straight forward, it was made from 2mm ply. Planking was something I have never done so a lot of research was done prior to starting. I decided to use a lime wood plank with a black 0.3 black card divider (caulk) all glued with aliphatic adhesive. I found the process quite enjoyable and the results on the test piece for a first attempt were quite pleasing. I then wanted to reproduce the nailing of the planks so I devised a small tool to ensure a consistent pattern Its simply a piece of obeche with four holes, 4 brass pins and a black divider line, this is simply placed on the join line and then tapped with a light hammer and filled with the tip of a black pen. The first attempt looks slightly misaligned but proved the system worked, I have made a more accurate one for the real floor. After the planks were set it was sanded flat which unfortunately leaves the wood grain blackened by the black card dust, however using a plastic eraser it’s easily removed ready for sealing. I thought that the door opening needed some sort of finishing/dressing so I decided to manufacture a mahogany door frame and handrail around the cabin.
Although a relatively new member and with no naval background at all I can only agree with the more informed, and thanks for the hard work that goes into maintaining a website like this its really appreciated. Michael T PS how do you open the excel file?
Welcome aboard Vosper21, again I have no experience of twin shafts but I am currently building the same boat and am just off the starting blocks in my blog as it does take time (the actual build is further on), but blogs are invaluable to other builders, so if you have any questions don't hesitate to ask. My blog is usually on the first page of entries as its an active one (The Vosper 46" RAF Crash Tender Kit By Vintage Model Works by M Turpin013) Michael PS have a look at robbob,s blog build its brilliant
I,m doing this part at the moment and as you say the parts are not very accurate, however its good to see what additional bits you added to solve the issues. A picture speaks a thousand words. Michael T
Now I have the cut blank material it needs to be cut into 3mm strips, this can be quite tricky as I found. As the fence was set to 3mm and the first cut was made the slice started to catch the back of the blade and knock some of the pieces off. So I needed to make sure that it was guided past the back of the blade. So as you can see I set another piece of Perspex behind the blade 3mm wide to hold the piece clear as the cut was finished. Next a trial fit of the pieces and it works just fine. Now I need to cut pieces to the length of the foam tanks ready for assembly. I need to cut some mahogany edging and a blank panel to complete the whole assembly. I then made a small jig to hold all the pieces together as they are assembled then each joint was “set” with a tiny drop of cyno and left to fully cure. When fully set I could then sand the surface to complete the tank tops, they will be varnished at a later date.
I wanted to recreate the foam tanks as another blogger has (Rob) so I tried to order some grating from one of the model suppliers only to find he was no longer producing the size I wanted (3mm) and that he was unfortunately running his business down. So what to do, how about make my own. First decision was what material to use; I wanted a close grain, quite hard, stable wood and after some searching I came across an item in IKEA of all places - a bamboo chopping board. So the first issue is reduce the board to 6mm thickness, fortunately I have a milling machine which using a large dia cutter blade cutter and clamping direct to the table I first machined to 8mm to see how much the material had bent having relieved surface stress, to my amasement it was perfectly flat, so I continued to size the material to 6mm. The best method of producing the pieces is use a method which advances the cut each time by using the previous cut as a gauge. This has to very accurate, so first set the fence at 50mm and plunge the table saw through a piece of flat board (I used a spare wooden floor tile) this gives the slot for the blade (3mm) at this point secure the board to the table with panel pins. Next move the fence a further 3mm (be as accurate as possible) and lift the board from the table and again plunge through making another slot next to the first, this slot has to be filled with a 3mm strip that protrudes above the surface by 3mm (this is the guide) I used some 3mm Perspex. Next re-attach the board in the original position and secure the board again. Now raise the blade to 3mm and make the first cut, followed by a second and check the advance is 3mm if all is well continue across the board for as many cuts as you need. TBC.
To enable ease of application of the side skins I decided to raise the building board up to 45 degrees, this allows a better view of the proposed joints Before fitting the bottom skins the side skins have to be trimmed back to the stringers and deck line again using a red pencil to show how much material is being removed as I approach the stringers with the plane. Having done that little job it’s time to shape the skin. I followed the same procedure as I did with the side skins. Again after some time I got a fit I was happy with from the stern to the start of the bow curve. At this point I pinned the skin at the B2,3,4,5 leaving enough material to trim to the bow curve and also trim the cut-out where the skin joins with a butt joint as opposed to the overlap from bow to stern, this is all done prior to bending. Notice the steel shim protecting the chine from being cut as the bottom skin is trimmed for the overlap of the side skin. The bending was done simply by soaking in hot water for 5 - 7 mins and then forming around a suitable size paint tin and left overnight to dry. I first pinned the stern end dry and then epoxied the bow area then followed by more epoxy and progressive pinning towards the stern using brass pins into the bulkheads and smaller pins along the overlap which will be removed when the joint is dry. I made a tempory clamping arrangement at th bow by pinning some scrap ply to the top beck atea to enable clamps to be used, notice the use of a mirror to be able to make sure the joint had come together
A lot of parks have now banned model boats in favour of wild life nature reserves, I have this issue with my local park Roundhay Park in Leeds Yorkshire there are two lakes both of which allowed model boats during the 60s/70s and IC at that. Both are now classed as nature reserves. I am in the process of challenging this issue with the local city council as today I am sure that wildlife and model boats (electric and sail) can share the same water space,watch this space.
Interesting article in Model Boats web site which mentions joggling, however I'm still none the wiser. http://www.modelboats.co.uk/forums/postings.asp?th=119534 and in addition an interesting article on decking in the Titanic Research and Modeling Association web site. http://titanic-model.com/db/db-02/bruce-1-db-02.html after some more research I found this comment by Ian Gardner "I find, when joggling planks into the waterway or king plank, it is useful, if you have the facilities, to grind a chisel the width of the joggling to chop out the recess in the waterway. This is usually one third the width of the plank being used if memory serves. The chisel can be made from a an old needle file and hardened after grinding." and pictures of joggled joints It appears its cutting into the waterway or king plank. In a way you can see the reason its called joggling as it gives the same profile as in metal joggling eg "Z"
The boat has to be placed upside down so first thing to do is to modify the base board so the hull is firm to be able to do any final trimming. Before the skins are fitted the bow areas have to be sealed being careful not to seal the parts which are to be glued The instructions say that the lower skins are fitted first and as they are 6mm oversize this allows for trimming to achieve a good fit. After some time I got a fit I was happy with from the stern to the start of the bow curve so at this point I pinned the skin at the B2,3,4,5 leaving enough material to trim to the bow curve prior to bending . The bending was done simply by soaking in hot water for 5 - 7 mins and then forming around a suitable paint tin and left overnight to dry. Before fitting I decided to trim the skin at the front bow area where it has a butt joint with the side skins, easier than trying to cut it out after it had been glued. Point to note was that while the bending was being carried out, I also bent he side skins as well. Having pre drilled all the holes for the pins and ensured the fit is as good as I can get I can now epoxy the first skin on.
Before fitting the skins the chine and gunwhale stringers have to be trimmed to the profile of the bulkheads, this is a time consuming job but is essential to get correct to ensure a good fit of the skins. Also final trimming of the bow k1,2,3 needs to be done now that they are fitted and “a virtual line can be drawn” to show where the skin will eventually sit flush. Using a red pencil to show how close to each bulkhead you have trimmed is a good guide’
Sorry I can't find the one I bought from Model Fixings but here is an equivalent tech data Bearing details bore 5mm OD 10mm Width 4mm 2 shields MB-032 Max rpm Metal Shielded Deep Groove Ball Bearings: One of the most commonly used bearings, these types are manufactured with metal shields inserted into the outer raceway, these fit in closely to the inner race providing protection against light mechanical damage, some protection against the ingress of moisture, dust and other foreign matter and serve to retain the pre-filled grease in the bearing. Shields can be easily removed for applications that only require 1 shield Benefits: Provides light mechanical protection, limits moisture and dirt ingress, lubricated for life, Branded MR1052Z Metal Shielded Deep Groove Ball Bearing 5x10x4mm £2.80 ex VAT Dynamic load C =0.4116 kN Static load Co=0.1568 kN Max speed=60000 rpm
Its all material I had lying around in my workshop, I never throw anything away so you can imagine the amount of "stuff" I have in my basement. The Yellow angle brackets are made of old neighbourhood watch signs they are made of 1/4" plasticard
Propshaft and oiler fitting Now for the fitting of the propshaft, fortunately I have a long series drill that will go through the keel and through the bulkhead B4 into the motor compartment; this went well and came out in the expected place. Next a trial fit of the tube in the keel and into the skeg, again this lined up perfectly and all that needed to be done was to epoxy it into place. First I nearly forgot to fit the oiler system to the prop tube, careful drilling and deburring and making sure no swarf is left in the tube. Finally wrapping a piece of plumber’s PTFE gas tape around the tube to ensure a gas tight fit (oil tight) we are ready to commit the tube to final fixing. Epoxy mixed and applied I put a couple of small wedges in the skeg to stop it moving and a wedge under the oiler to make sure it was horizontal.
Prop shaft bearing I purchased a standard propshaft with Phosphor bronze bearings again from a well-known supplier, however I had also fancied a Raboesch type with a bearing at the motor end however at £30 plus think again. So I researched the bearing type and found at £2.50 each it was worth a go at making my own so quick sketch and an order placed from Modelfixings.com. A simple piece of machining and the part was made. A simple enough job to remove the existing bearing and slide on the new housing and it made a significant difference to the “feel” of the shaft when rotated. I also made a simple collar to retain the shaft in the hosing.
Skeg Having seen the trouble others have found with the suggested method of production I decided to go straight for the robust version. I did a number of measurements to determine the size and shape of the arm and went for 2mm brass sheet. The tube was machined from 12mm dia brass with tapered ends to 8.5mm and an 8mm bore to suit the tube. Next I machined a 2mm slot the length of the tube to locate the brass arm in. Keeping the pieces spotlessly clean (not forgetting to clean the solder rod as well) the items were fluxed and wired together to keep then in a true vertical position whilst they are silvered soldered. A keen eye on temperature and a light touch and clean flow with the solder is recommended to keep final dressing to a minimum.
At this point I decided to fit the rudder tube, water pick up and skeg. I was able to mount the boat in the machine vice by gripping the keel; this ensured that the holes are drilled absolutely true and square, 2 x 8mm holes are needed to take both the rudder tube and water scoop. I purchased the rudder assembly from a well-known supplier but I didn’t like any of the proprietary water scoop tubes on offer so decided to make my own. Whilst the boat is in the vice I also decided to machine the slot for the skeg to fit in. This required drilling a series of 2mm holes and then opening them up into a slot using a long series slot drill again giving an accurate slot which the skeg can locate into. Water scoop Having dealt with the woodwork, I turned my attention to metalwork. To bend the ¼” brass tube successfully it has to be annealed, (cherry red and quenched in water), then inserting a tight fitting spring inside the tube to stop any kinking I gently pressed it round a former to the correct shape. Springs removed I filed the end to the correct angle which gives an oval opening, but the end didn’t look finished, so I machined a thin spacer and then squashed it to suit the oval end and silver soldered it to the end of the tube, this gives a much better visual appearance.
Chine stringers Again first job is to trim all the bulkhead corners so the stringers sit flat against each bulkhead. We can then start to trial fit each side to see what sort of curvature we need. This time I needed a tighter curve (2.5 litre paint tin) so again using a scrap piece chip board I made another jig. The stringers are fitted in the same sequence as the gunwhale stringers that is the first pair are trial pinned, then epoxied and fully pinned. When fully set the second pair can be fitted but this time using clamps only, no pins, to allow for trimming at a later stage. Then allow some time for it to set and check that all this tension in both sets of stringers hasn't caused any twisting or misalignment.