Killybegs Posted January 14, 2015 Author Share Posted January 14, 2015 Once I get either my Mitchell Mougul or 4500 chassis working I think I will give it a go. Not had a whole lot of success getting the clearances right on an outside cylinder p4 loco yet, the Mougul has given me no end of problems! I can sympathise with that but if you think the Mogul is difficult try the Castle! You definitely need to washer up the front drivers to eliminate any slack which I find means putting more play on the rear axle. I have a MM 4500 to build down the line and a second Mogul waiting to have the body finished (it's only been in that state for 15 years!). 1 Link to post Share on other sites More sharing options...
RMweb Gold The Fatadder Posted January 14, 2015 RMweb Gold Share Posted January 14, 2015 Thanks, Will give that a try and see how I get on. Link to post Share on other sites More sharing options...
Rail-Online Posted January 14, 2015 Share Posted January 14, 2015 Once I get either my Mitchell Mougul or 4500 chassis working I think I will give it a go. Not had a whole lot of success getting the clearances right on an outside cylinder p4 loco yet, the Mougul has given me no end of problems! If you are feeling lazy the Mitchell chassis fits OK under the Bachmann body - just a little tweaking required. Tony Link to post Share on other sites More sharing options...
Killybegs Posted January 15, 2015 Author Share Posted January 15, 2015 More detailing has been done, this time at the front of the loco. The steam pipes have been replaced (including filling the gaps left in the footplate and smoke box cradle), the boiler support bracket has been 'upgraded', replacement steps have been fitted to the front of the tanks and a few bolt heads have been added. The smoke box front is next on the list, then its handrails and lamp irons. 12 Link to post Share on other sites More sharing options...
Popular Post Killybegs Posted January 20, 2015 Author Popular Post Share Posted January 20, 2015 Progress on the Prairie continues. Buffers, vac and steam heating pipes, couplings and boiler bands still to go on. Then, of course, there's the chassis to build as this is one is on loan from 5173 (previously 6154, renumbered as a Gloucester loco to suit Worseter). 20 Link to post Share on other sites More sharing options...
sp1 Posted January 20, 2015 Share Posted January 20, 2015 There's that lovely coaling wotsit again! Link to post Share on other sites More sharing options...
Killybegs Posted January 21, 2015 Author Share Posted January 21, 2015 All the outstanding bits are now fitted so tomorrow it will get a good clean and an undercoat. 12 Link to post Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted January 21, 2015 RMweb Premium Share Posted January 21, 2015 Looking good, only one comment, should there be a lamp iron in the bunker recess? Link to post Share on other sites More sharing options...
Killybegs Posted January 21, 2015 Author Share Posted January 21, 2015 Looking good, only one comment, should there be a lamp iron in the bunker recess? Yes! Well spotted. Link to post Share on other sites More sharing options...
Killybegs Posted January 22, 2015 Author Share Posted January 22, 2015 The missing lamp iron has been duly fabricated and fixed in place. I also adjusted the positions of a couple of the bunker steps as the middle one was far too high. Then it was off to the sink for a good scrub (the loco, not me!). In the end I decided not to bother with boiler bands as I couldn't find anything thin enough so, once everything was dry, on went a couple of light coats of primer. 13 Link to post Share on other sites More sharing options...
Killybegs Posted January 27, 2015 Author Share Posted January 27, 2015 My old Prairie has been feeling a bit left out lately with the new upstart getting all the attention, so she decided to change her image. In her new guise as 5173 (a Gloucester engine), she is a little grubbier than before but is delighted to be reunited with her chassis. She celebrated by going out for a spin at Worseter, where she is seen here crossing the Worcester and Birmingham Canal. Meanwhile, the upstart has had a nice glossy coat of paint and is awaiting transfers, numbers and light weathering. Oh, and her own chassis of course! 19 Link to post Share on other sites More sharing options...
Killybegs Posted January 30, 2015 Author Share Posted January 30, 2015 OK, that's what a dirty Prairie looks like. Here's a clean one! It won't stay that way for long but it's only going to get light weathering. However, it's twenty years since I did any light weathering with an airbrush so I will have to get in a bit of practice first! I have also been looking at what I am going to do with the chassis. I have dug around all my bits and pieces left over from other kits and find that I don't need to buy anything, which is great as the whole plan was to do this project on a shoe string. Apart from the £25 spent on the loco, I have only had to buy wheels, motor, gearbox and number plates. The chassis was originally designed to be fully compensated with a Portescap motor and gearbox driving the centre axle. This one has a Mashima 1430 motor with a High Level LoadHauler+ gearbox. I also decided to have a rigid driven axle and initially this was going to be at the rear, which is the normal configuration. However, in P4 there can be problem with clearances between the front wheels and the crosshead, so I decided to see if my motor/gearbox combination could go on the front axle and fit within the confines of the bodywork. It did, just! This did mean a slight modification to the size and orientation of one of the frame spacers and this is illustrated below. It all works in Autocad, now I have to build the chassis and see if it works for real! 13 Link to post Share on other sites More sharing options...
RMweb Gold The Fatadder Posted January 30, 2015 RMweb Gold Share Posted January 30, 2015 Interesting way of doing it, will be good to see how it works in practice before I fet going on mine. Link to post Share on other sites More sharing options...
Killybegs Posted February 4, 2015 Author Share Posted February 4, 2015 Well, that's the basic chassis soldered up on my trusty Avonside jig. By putting the chassis back on the jig I will be able to set up the compensation beam accurately as the setting up pins will keep all the bearings in line. That's the theory anyway! Rich, the proposed compensation system is the same as used by Malcolm Mitchell on his Mogul kit except that has the rear axle fixed and I've opted for fixing the front axle on the Prairie. 4 Link to post Share on other sites More sharing options...
Killybegs Posted February 4, 2015 Author Share Posted February 4, 2015 (edited) Continuing from the last post, the compensation beam has now been fabricated. This is made up from the two beams that are on the chassis etch and are designed to sit either side of the gearbox on a fully compensated chassis. As my gearbox is on the front fixed axle these have been laminated together along with spacers from some scrap etch. The spacers gave me the extra depth needed for adjustment to make sure the chassis would sit level on its wheels. You can see from the arrows that only a couple of thou extra was needed. from above from below Edited February 4, 2015 by Killybegs 7 Link to post Share on other sites More sharing options...
Dave Holt Posted February 4, 2015 Share Posted February 4, 2015 (edited) Hi John. The body for this project looks really nice, however, I think you're going to have to be very carefull with the weight distribution with your compensation arrangement to avoid the risk of lifting one side of the fixed axle on curves. The three points of support are the two wheels of the fixed axle and the centre of the rocking beam - a very short triangle. For maximim stability, the loco CoG needs to be between the base of that triangle (i.e. the fixed axle) and the centroid, which is one third of the distance to the apex (mid point of your beam). If it's nearer the apex, the loco will be potentially unstable. To keep the CoG in the prefered zone is going to give very uneaven weight on each axle. My first two locos used a similar arrangement to the one you are proposing and had the wheel lifting problem. In the end, I had to re-design the suspension to lenghen the support triangle and ended up with a fully foating compensation arrangement. You could have twin beams on the front and middle axle and still limit the front axle side-play, and than either a simple centre rocking pivot on the rear coupled axle or, preferably, a central beam between the rear coupled axle and the rear truck. That will give excellent stability and enable a really good weight distribution if you choose the rear beam pivot point appropriately. Dave. Edited February 4, 2015 by Dave Holt Link to post Share on other sites More sharing options...
Killybegs Posted February 4, 2015 Author Share Posted February 4, 2015 (edited) Mmmm, thanks Dave, that's a bit unfortunate ! My CoG is over the centre driver which puts it on two thirds of the way to the apex. I could take some weight out of the bunker but, as you say, that would give a very uneven weight distribution. I haven't had any problems with my Mogul which has a similar system and a worse weight distribution, so I think I will plough on and see what happens. Anyway, thanks for the advice. I'm surprised you didn't spot the missing frame spacer that the pony truck pivots on. That was much easier to put right! Edited February 4, 2015 by Killybegs Link to post Share on other sites More sharing options...
RMweb Premium TrevorP1 Posted February 4, 2015 RMweb Premium Share Posted February 4, 2015 An Airfix 61XX body has just arrived courtesy of eBay. As if I didn't have a enough to do already... Never mind, a project for every mood! 3 Link to post Share on other sites More sharing options...
Killybegs Posted February 5, 2015 Author Share Posted February 5, 2015 Good man Trevor, you can learn from my mistakes. After completing the basic chassis, the next step was to fix the mountings onto the body. I had already done most of the prep work on the body, the floor of the bunker had been fixed high to leave room for a 0.5mm thick mounting plate and the front mounting piller for the Airfix chassis had been removed. The rear mounting plate was cut out of a sheet of nickel silver in which a hole had been drilled and a 10BA nut soldered to the rear. A hole to take the nut was drilled in the styrene base of the bunker, the plate was checked for alignment and fixed with epoxy. The gap under the smoke box was filled with styrene (Butanone works well between styrene and the plastic body) to bring it level with the underside of the footplate. As the chassis at this point is approximately 1mm lower than the underside of the footplate (over the cylinders) a larger square of 0.5mm styrene was added. The nickel silver fixing plate followed the same process as at the rear. Once everything had set, it was apparent that there was still a slight gap between the top of the cylinders and the mounting plate. One layer of 0.25mm styrene secured to the nickel silver with Butanone (wonderful stuff!) cured this. In addition to the lead that is visible in this photo, there is also a lot in the bunker and boiler! 15 Link to post Share on other sites More sharing options...
Killybegs Posted February 10, 2015 Author Share Posted February 10, 2015 (edited) Next up are cylinders, cross-heads, coupling rods, etc. Very fiddly and time consuming to get everything working smoothly. First the various components Then the final assembly. At some point I will need to make some wrappers for the cylinders. I guess I will have to sort out the wheels next, before making a start on pony trucks, etc. Edited February 10, 2015 by Killybegs 8 Link to post Share on other sites More sharing options...
Killybegs Posted February 12, 2015 Author Share Posted February 12, 2015 Well, after a lot of blood (not really), sweat (definitely) and tears (I fought them back), I have the basic chassis up and running beautifully. I spent a long time making sure the crank pins all went in straight and everything ran smoothly first time. This entirely due to building the chassis on a jig (Avonside) and assembling the wheel sets in a wheel press and quartering jig (GW) and nothing to do with me! I did a great deal of measuring before hand and this showed that I would have to make the following alterations to the wheels: Reduce the bosses on the outside face of the front drivers so that the crankpins would clear the back of the cross heads Reduce the bosses on the inside face of the middle drivers to give me 0.5mm side play I also reckoned I would need a couple of half etched washers to reduce any play on the front drivers. In the event it didn't quite work out like that. I fitted the rear drivers first and they were tight on the bearings so I filed down the face of the bearings a little. On the basis that the other axles would be similar, I also filed down the bearings for the middle drivers (not as much, as by now I had realised I had taken off too much at the rear!) and left the washers off the front axle. Perfect, or it would have been if I hadn't forgotten to reduce the length of the front axle to match the reduced wheel bosses. Once that was done they were great. Having test run it on the track, it's clear I will have to fit washers to the rear axle to reduce side play. The loco was sitting a bit low at the back so I slipped a bit of thin card between the compensation beam and the rear axle. After that it was spot on, so I know what thickness brass shim to solder onto one end of the beam. While I have the wheels in, I will get on with the front and rear bogies and get those set up before stripping it down and finishing of the detailing before painting. 12 Link to post Share on other sites More sharing options...
RMweb Gold Mikkel Posted February 12, 2015 RMweb Gold Share Posted February 12, 2015 What a difference that chassis makes to the body. It all looks excellent. One of the many things that really stand out in the shots of your embankment on Worseter are the chassis of the locos, they really come into their own there. 1 Link to post Share on other sites More sharing options...
Killybegs Posted February 16, 2015 Author Share Posted February 16, 2015 It's looking a lot better with a full set of wheels! I had to scratch build those components of the quite complicated front pony truck that must be on the body etches. Fortunately, I have the kit that I built 20 years ago for reference. 17 Link to post Share on other sites More sharing options...
Dave Holt Posted February 16, 2015 Share Posted February 16, 2015 John. Yes, much better with all wheels present. One initial thought, with my LMS/BR eyes, was that the lower struts of the pony truck slopes down at rather a steep angle but reference to the rather notorious Roche drawings confirms that it does. This has all the makings of a fine looking model - a silk purse, indeed! Dave. Link to post Share on other sites More sharing options...
Rail-Online Posted February 16, 2015 Share Posted February 16, 2015 (edited) Dave, Trusting a Roche drawing -never! However here is the best neg I can find (it is always in deep shadow) in which you can JUST make out the angle of the strut - it is correct! Cheers Tony Edited February 16, 2015 by Rail-Online Link to post Share on other sites More sharing options...
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