| Model Ship Builder :: Forums :: Build Logs :: POB Build Logs |
|
<< Previous thread | Next thread >> |
| Greek Bireme (Amati) - 1:35 | ||
| Go to page 1 2 3 4 5 6 7 | |
|
Moderators: Winston, aew
|
| Author | Post | ||
| Tim C |
| ||
  Registered Member #4126 Joined: Fri Feb 15 2013, 05:19amPosts: 1113 | Wow, Looking forward to seeing this when it's done. Later 42rocker | ||
| Back to top | | ||
| aew |
| ||
Arthur  Registered Member #1929 Joined: Wed Nov 30 2011, 03:05pmPosts: 3019 | Mike: Definitely the latter! 42rocker: Follow the website link if you want a sneak preview.  [ Edited Mon Feb 18 2013, 10:45am ] | ||
| Back to top | | ||
| aew |
| ||
| Arthur Registered Member #1929 Joined: Wed Nov 30 2011, 03:05pmPosts: 3019 | 8th May 2009 I’ve now built the electronics that drives the two servos. The available space dictated the design. The bulkheads are 23mm apart. Electronic components are made to a 0.1” or 2.54mm pitch. That meant that I only had 9 tracks of circuit board to play with. The length available varied but at best was similar to the height. This was the first part of the circuit: I’m using a spare 12 V power supply and this is the 5V supply for the servos and some suppression for the rest of the circuits. It’s 23 x 13mm (About 1” x 1/2”) PICT_B_0501  This next bit of circuitry drives the servos. Both servos will simply motor to one end at this point. This one is 23mm square. PICT_B_0502  This is the bit that varies the servo position. One output rises and falls repeatedly, the other is on whilst the first is going up and off when it’s going down. The one that’s rising and falling moves the servo to sweep the oars, the one that goes on and off switches the servo that raises and lowers the oars to the other end of its travel. PICT_B_0503  This board presented a challenge! It’s the biggest of the three and although it’s still only 23mm high, it’s 31mm long. Looking at the available space, I could fit the first two circuits along side the servos and somehow I would have to fit the third circuit between bulkheads 1 and 2. As the ship narrows considerably at this point, this meant it would have to go in the middle, there wasn’t room on one side of the keel. The only way to do this was to cut a slot through the keel. To keep the size of the slot to a minimum (it had to go under the drive rod) I made sure all the components on one side were laid flat. Those on the other half, in common with the other circuits, are mounted on end to minimise the board sizes. The following pictures show the boards in place: PICT_B_0504  PICT_B_0505  As you can see, that was a very tight squeeze! It’s to be hoped nothing goes wrong because once I plank the hull, there’s no way I will be able to get at this lot! I think I have just enough room to refine the mechanical design slightly. Although the cross piece is soldered to a central drive rod, there is some flexure in the arrangement. A tie rod from one of the arms to the front of the drive rod should solve this. Then it’s time for some conventional modelling! | ||
| Back to top | | ||
| aew |
| ||
| Arthur Registered Member #1929 Joined: Wed Nov 30 2011, 03:05pmPosts: 3019 | 13th May 2009 As you’ve probably noticed, I have already planked the underside of the outriggers to keep all the bulkheads in line. I was rather puzzled by the wood supplied. Identifying what goes where is another puzzle, but there is a bundle of dark wood, possibly walnut, labelled ‘Hull Planking’. The first bit of the puzzle is that consists of two different lengths of 3 x 1mm, approximately 34 pieces each of 330mm long and 580mm long. The outriggers are 355mm long so I used 6 of the longer pieces to plank under them. I will also need the longer pieces to plank the sides where the oars emerge. The top planking is shorter, as the last section where the helmsman stands is open at the top so I can use the shorter lengths here. However, this will require less than half of these planks. I don’t think there are sufficient long planks to do the hull itself so I am expecting to have to have some joins. There is a second bundle, I suspect of beech, 3 x 1mm x 450mm long. This is labelled ‘Deck Planking’ and again contains approximately 34 pieces. Again, it looks as though this is about double what will be required. Why do I have that nagging suspicion that I’m missing something? There are some other pieces which, despite attempts in the notes to confuse you, look more straightforward. There are two 8 x 2mm strips which I believe are for the seats – the notes say ‘Covering thwarts’ so that seems OK. There are two beech? strips 5 x 1.5mm which I think are the wales. The plan says the wales must be shaped from 5 x 1.5mm strips but elsewhere the notes say the wales are beech strips 3 x 1mm. However, there are 2 additional pieces of this section, 400mm long. So far I haven’t spotted what these are for. There are a couple of 1mm square strips to frame some doors on the deck and a piece of 3mm square beech? that will probably be for some posts and rails. All the wood looks to be of very good quality. There is a note on the plan near the stern that says ‘To fill with tender wood all the dashed part in the two sides from frame number 18 and on’ but no such note at the bow. It was a bit of an inspired guess as to the shape of the blocks at the stern, but I needed to modify the bow considerably from the way the kit depicts it. The pictures and drawings show the sides follow a smooth curve up the prow. If you look at the picture of the ram, the top is flat and the section that wraps around the bow meets it at an angle. I therefore glued some blocks either side of the bow and carved these to something like the shape of the ram. PICT_B_0601  Note: This picture also shows the tie rod I referred to in the previous entry. The next picture shows the first four planks fitted either side of the keel. Although I tapered these at the stern, I opted to run them straight through at the bow. As there is virtually a right angle corner here, the planks on the sides will cover the cut ends later. PICT_B_0602  As you can see, I have resurrected my paperclip planking clamps, but because the hull is so shallow, I had to cheat to get some tension in the elastic bands. Rulers have other uses besides that of a measuring stick: PICT_B_0603  If you look in the background to this picture, you can see my initial attempt to modify the stand. Although it looks quite respectable, it suffers from the dreaded exposed plywood edges. I decided to glue some strip wood along the edges to form a lipping. This was the first attempt to make it conform to the required shape. Although the wood was very pliable when dipped in boiling water, holding it in the correct shape proved to be a problem. I eventually resolved the problem as follows: PICT_B_0604  The two outer pieces are the actual pieces the stand was cut from, but trimmed slightly on the scroll saw to allow for the thickness of the strip. I left them ‘clamped’ until they dried and then removed them, applied some glue, and re-clamped them. The clamps and steel ruler are only there to keep things flat; the assembly was rather unmanageable without them! The piece in the foreground is the base of the stand with the lipped edge to the front showing just how well it’s turned out. I am currently fitting the first two planks that curve up the sides of the stern. These are proving to be a major challenge and will dictate how subsequent planks fit here. | ||
| Back to top | | ||
| aew |
| ||
| Arthur Registered Member #1929 Joined: Wed Nov 30 2011, 03:05pmPosts: 3019 | 25th May 2009 If you want a challenge in hull planking, I can recommend this kit! You name it, this model has got it. Tight bends, both in thickness and sideways, sharply curved bulkheads, profiles that switch from convex to concave, planks that twist almost 90 degrees and finally some right angle corners. (Oh, and plenty of dropped planks and stealers as well). As an added complication, both sides of the finished planking will be visible. Any mistakes will be harder to cover up there as it will be very difficult to sand the inside of the hull. This is going to be an interesting exercise. The following picture shows the plank I referred to in the previous post. This plank is bent sideways to follow the curve of the stern. The section running along the blocked part of the stern is butted against the bottom planking but as it leaves this section, there is a transition and forward of this area it will be mitred to the bottom plank. PICT_B_0701  Three more planks have been added in the next picture. The first was a dropped plank starting just short of the outrigger (the end is just visible under the rubber band) and running all the way to the bow where it forms the upper side plank on the ram. The second plank was the interesting one. In the centre, it lies side by side with the first plank. By the time it reaches the area of the rubber band, the slight bevel to its edge has become a pronounced mitre and under the blue clamp the planks are almost at 90 degrees to each other. Finally, the section up to the red clamp is laid inside of the other plank forming a butt joint. The third plank was relatively straight forward to fit, but as you can see it has a 90 degree twist in it, It is laid horizontal under the stern but is vertical along the sides. PICT_B_0702  The next picture shows these three planks at the bow. The top and bottom of the ram meet the sides at more or less right angles. A little cheating has taken place here. On the top of the ram, the upper and side planking is mitred together, but underneath, the bottom planking is simply butted up to the side planks. The third plank here has a significant inward twist to it to conform to the second bulkhead (under the centre rubber band) but then twists out again to the sides of the ram. If you look at the stand, you can see the end of the screwed rod holding the model in place. This is the electrical connection for the power supply. PICT_B_0703  The final picture shows the planking on the bow. This planking starts in front of the outrigger sections on bulkhead 3 and runs to the stem. The first problem is that there is nothing to fasten this planking to at bulkhead 3. I therefore planked the outer part of this bulkhead, the part that forms the end of the outrigger section. This gave me something to hook the planks behind. The second problem was what to do with the stem. The picture on the box shows the conventional arrangement with the planking fastened to the side of the stem (rebated) and with a brass strip fastened to the front of the stem. However, the ram obviously fitted on a bow that ended at a sharp point. I have now chamfered the stem such that I can plank it all the way to the front. The thickness of the upper part is such that hopefully, when planked, the total thickness should just equal the width of the brass strip. The lower part is thinned down to bring the planks together. The top of the ram is now planked and two stealers have been fitted as the first step in planking the sides of the prow. PICT_B_0704  The decorative strip can be seen in the foreground. Transition from a pointed ram to a flat strip might be a challenge but I’m not short of big hammers! (Much later, I found that the upper front section of the ram is flat, unfortunately mine isn't!) | ||
| Back to top | | ||
| bbrockel |
| ||
  Registered Member #1520 Joined: Sat Mar 12 2011, 04:39pmPosts: 136 | Makes you wonder just how they planked the prototype? Use giant clamps and rubber bands? Nice job on a cool ship. | ||
| Back to top | | ||
| teleman |
| ||
 Registered Member #1925 Joined: Tue Nov 29 2011, 05:32amPosts: 1394 | Hey Arthur you use to be a race car driver I see. Because you sure did handle those hairpin turns with the planks very well.... | ||
| Back to top | | ||
| aew |
| ||
| Arthur Registered Member #1929 Joined: Wed Nov 30 2011, 03:05pmPosts: 3019 | Bob: Possibly their trees grew that shape so the designed the stern to match the trees? Mario: I think later instalments show how I bent the planks. If they don't, I'll find the picture and post it separately. | ||
| Back to top | | ||
| aew |
| ||
| Arthur Registered Member #1929 Joined: Wed Nov 30 2011, 03:05pmPosts: 3019 | 7th June 2009 Continuing with the planking. I had reservations as to the number of long planks supplied, so I set aside 6 long planks for the sides of the outriggers. I also took out 10 of the shorter planks for the tops of the outriggers. There would be off-cuts from the 6 long planks which I could use for the bow and stern planking, but other than these, the remaining planks had to complete the hull planking. I opted to use some of the shorter planks on the bottom of the hull. The bottom of the hull is relatively straightforward and joints were not a problem. The planks run more or less parallel from bow to stern, but it was necessary to drop planks progressively at the stern. It was easiest to do this in reverse. I notched the plank that was already in place to accept the dropped planks. At the bow, because there is a right angle corner with the side planking, the plank ends were simply mitred to fit. A little judicious planing of the edges of the planks was required to get the sides of the gap parallel. PICT_B_0801  I taped a few off-cuts of planking together to use as a gauge as the sides came together. Two planks to go on the port side and one on the starboard side. PICT_B_0802  Nearly there. PICT_B_0803  The next picture shows the bottom of the hull complete. The ends of the dropped planks can be seen at the stern. PICT_B_0804  Now for the bow and stern sides, these have very pronounced curves. I found a tin of the appropriate diameter to bend the stern planking round (it’s a beeswax tin!) I stood the tin on a piece of scrap chipboard and hammered a couple of nails behind it to stop it sliding backwards. I also placed a plastic bag between the tin and the board so I could wet the plank more easily. Having soaked a plank for 20 minutes or so, I clamped the end down to the board. I had to use a substantial clamp to keep the end against the tin, the plastic ones weren’t up to the job. It was then simply a case of working along the plank clamping it down to the board. The clamps are required to stop the plank twisting rather than to actually bend it. It was easy to keep the plank wet because of the plastic between it and the board and by applying steady pressure the plank was eased in until it was up against the tin. The plank was then left to dry completely. Once it was dry, it could be removed without losing its curvature and trimmed to its final shape. PICT_B_0805  The sides of the bow pose a slightly different challenge. The top plank has a similar curvature to those at the stern, but the lower planks are virtually straight and horizontal. In this case, several stealers are required in a comparatively small area. The following picture shows the top plank in place and the area beneath it to be planked. PICT_B_0806  The final picture shows the first stealer in place. The lower end will be shortened slightly to remove the point. PICT_B_0807  These last two pictures also show the lower deck planking which covers the mechanism. I actually bought some 5 x 1mm planking for the lower deck as the instructions specify 1 x 3mm and notching this around each bulkhead would have been very difficult. The two outer sections are loose at the moment. When I’m feeling brave, I’ll consider gluing them in place. When I complete the hull planking, I will have one long and three short lengths of planking left, so although there is sufficient material, more of the longer pieces would have been preferable. | ||
| Back to top | | ||
| aew |
| ||
| Arthur Registered Member #1929 Joined: Wed Nov 30 2011, 03:05pmPosts: 3019 | 12th June 2009 Yet more planking. I’ll start with a couple of more recent pictures of the hull planking. I use a scraper in preference to sand paper where possible and in these pictures the starboard side has been smoothed but the port side is as yet untouched. The first picture shows the stern with the majority of the inner planks, which run parallel to the keel, notched into an outer plank that follows the curvature of the sides. PICT_B_0901  The next picture shows the difference at the bow. Here the sides are vertical and they form a right angle corner where they meet the bottom planks. This means that the side planks cover the cut ends of the bottom planks. PICT_B_0902  Now back to the planking on the sides of the bow. Once the top plank was in place, this wasn’t as difficult as I had expected. Although there are more stealers than full planks, it was a fiddly job rather than a difficult one. The open top made it easy to clamp the planks in position whilst the glue was setting. The hardest part was cutting the front of the lower planks such that they met at a sharp point. Hopefully, this will be covered by the ram anyway, but if the bow comes out the right shape, making a ram to match should be easier. This picture shows the completed bow planking. The modified shape has turned out pretty well. The lower side planking meets at a sharp edge where the ram will fit but above that the bow will be covered with a 6mm wide brass trim. PICT_B_0903  The following picture shows the bow from above. I think this was actually taken before the previous picture as the planking doesn’t appear to have been cleaned up. The top of the second bulkhead (the short one) has since been covered with a capping strip. This is the only one that would have had an exposed edge, the tops of the others will be covered by the deck planking. PICT_B_0904  Now for the stern planking. The top of the stern is planked and forms a sort of middle deck. Only part of it will be in full view, the centre section will be partially obscured by the deck planking. A minor bit of cheating took place here. The final bulkhead (No. 18) breaks the rear centre planks in two whereas the previous two bulkheads, (Nos. 16 & 17) have cut outs through which the planks run. As with the lower deck planking, it was easier to fit a notched plank either side of the central uprights than to fit a central plank. However, from the last bulkhead up to the stern, I used a central plank. The discontinuity will not be visible later. The outer planks of this section were relatively straightforward as, although they bend significantly in the usual direction, they don’t bend much sideways. They taper to half width at the stern. From this point on, it was simply a matter of filling in the gaps, though I did have to glue some support strips to the front of bulkhead 18 to support the ends of the planks which stop there. PICT_B_0905  The next planks, those that fit on the sides of the stern, were some of the hardest to fit. The lower ones weren’t too bad but the uppermost ones were quite a challenge. The very top of the stern called for a very tight sideways bend and the planks also twist along their length. It was also necessary to fit a short stealer at the front of this section. PICT_B_0906  The sides and tops of the outrigger sections should be relatively simple, although I do need to be careful where I drill my oar ports. The upper deck planking also looks straightforward but I haven’t worked out where the wales run to at the stern. The brass trim runs along the wales and ends up at the top of the stern. How it gets from the wales to the stern is something I haven’t figured yet. | ||
| Back to top | | ||
| Go to page 1 2 3 4 5 6 7 | |
Powered by e107 Forum System