walkingthedog Posted January 14, 2019 Share Posted January 14, 2019 After all the work you have put in it would be a shame not to persevere. Link to comment Share on other sites More sharing options...
96RAF Posted January 14, 2019 Share Posted January 14, 2019 Keep at it Ken.Its only engineering, there is a solution out there, just needs finding.Going to be out of the loop in a day or so as I decamp Cyprus back to UK.I will make direct contact with a hotmail address as my cytanet email will die on me end of this week.Rob Link to comment Share on other sites More sharing options...
Go_West Posted January 15, 2019 Author Share Posted January 15, 2019 /media/tinymce_upload/617f2ef1e1b0300a8d0d9c4550680575.jpgNow with the new parts installed the engine was run once more and this times things were much better it was a bit stiff but as a fellow engineer used to say “its only the newness”And after setting and resetting the valve timing and letting the engine run for 30 minutes it soon showed that the extra work paid off and it had lots of steam and power the speed at full boiler pressure was great enough to run the engine off the curves despite its slightly smaller wheels./media/tinymce_upload/04fc40be4568fda16ad1caab75053c5b.jpgHere you see it as I have just managed to catch it as it nips round my small track with 2 coaches on/media/tinymce_upload/46ecb1117eb9b0054c9490d594d83dc4.jpgI did add a set of rubber tyres to the third set of drivers these were the standard Hornby tyres for the A3 and A4 and appear to fit ok./media/tinymce_upload/30652e6928df3af488b3b119c424412d.JPGI still have the problem with the rear truck wheels and as you can see from these pictures just how far the rear end of the chassis swings over the rails making things hard to work as the full size engine with flanged wheels./media/tinymce_upload/b2cba4573c3bd0b9bdcd18f51d437389.jpg/media/tinymce_upload/626bb09612da4635ec6b605d104b47ac.jpgAnother problem I found was the pivoting Hornby connecting rods these seam too flexible and would lend them selves to locking up the wheels and in some cases jam the quartering or slow the engine down so a quick fix was to solder the flexible link on the rear of the rod on the second driver this was the wheel set connecting to the piston and was therefore delivering all the power to the wheels especially the set with the rubber tyres on./media/tinymce_upload/979bbfa59d1da320e91f9a331972d8c4.jpgThe fixing points were made to fit the body to the chassis this way I could get an idea as to how thing were working out and all looks fine the steam exhaust from the working chassis was almost directly under the hole in the brass body so no real problem there the only thing to change was the very front of the oil tank which needed more of an angel to match the angel of the front of the brass body so a little filing and this fitted better./media/tinymce_upload/44590bfb8e5cfa2ab79c44aff7969596.jpg/media/tinymce_upload/af543690b3ac61bb9bfded6359cdb270.jpgStill thinking on the working valve system for the model i came up with this idea which is to take the drive from the Hornby valve system and extend it out the front of the valve cover and with a small double pulley and 2 rubber o rings drive 2 small shafts above the cylinders and then down to the second drivers this way as the engine moved along the small shafts would rotate and look like the full size engine but we will see as there is still much to do on the chassis and body./media/tinymce_upload/e3ba2a441be963fb2e9623355586446b.jpg/media/tinymce_upload/e91da55f7b1cb43e11ed7374c6770379.jpg Link to comment Share on other sites More sharing options...
96RAF Posted January 15, 2019 Share Posted January 15, 2019 Superb KenRob Link to comment Share on other sites More sharing options...
walkingthedog Posted January 15, 2019 Share Posted January 15, 2019 I knew you’d get it to work. Well done. Link to comment Share on other sites More sharing options...
Go_West Posted January 22, 2019 Author Share Posted January 22, 2019 i have a few parts now made to the above valve system so will try to explain it .............../media/tinymce_upload/fdadabacc0bf6c01fdd40edf8fd492ed.jpg Here I have made up the main parts of the valve drive system that I hope might work from the drawings put here a few days ago.Starting from left to right the first part is the small black valve which rotates to send steam to the cylinders at the right time it also does the exhaust side of the cycle at the same time.This small valve has a steel pin set in it and its this pin that will drive the second shaft and drive the rotating valve shafts.The next part is the second shaft which as you can see from the picture has a slot cut in it to take the drive pin.The 2 holes in this shaft boss are for locking the shaft so that the nut on the other end of the shaft can be tightened against the pulley wheel./media/tinymce_upload/bafdaae102a168c72d3832a8e78bf1c4.jpgNext is the bronze washer followed by the spring that keeps the valve on the valve face and the second shaft in contact with the back of the valve.Next is the gasket and the valve cover with a hole drilled in it to take the bearing housing which is the next part and will be silver soldered in place.After this is the O ring seal then the glad nut then the double pulley and last of all the nut to lock the pulley to the shaft. /media/tinymce_upload/bed1a0aa4652a12202b1fa431c0c3bbb.jpg/media/tinymce_upload/dd9df8cdd14cc8964129ceaf83a0d254.jpgNow we come to the output shaft In this picture top right hand is the drive belt below this are the 2 screws and the bracket to fix to the top of the cylinder block.The output bearing housing will be solder in place on the bracket.The shaft its self has a wing nut look to the left hand end of it, it is this that will connect to the shaft and give a flexible joint when it revolves. I hope this all makes sense. I will build up just one side of the system to see if it works if it don’t then will opt for a static build and bin the parts. Link to comment Share on other sites More sharing options...
96RAF Posted January 23, 2019 Share Posted January 23, 2019 Good progress Ken. I can just about imagine me trying to assemble those tiny parts, but making them in the first place is well out of scope for me.For anyone wondering about those grooves, the steam valve unit pulley has twin grooves to drive the dummy valve gears as seen in the schematics earlier in this post. The dummy valve gear drawing immediately above only has a single groove to confuse those not paying attention.Rob Link to comment Share on other sites More sharing options...
2e0dtoeric Posted January 23, 2019 Share Posted January 23, 2019 A belt groove for each of the dummy valves, I presume (l and r). Link to comment Share on other sites More sharing options...
Go_West Posted January 23, 2019 Author Share Posted January 23, 2019 Ericm0hffyes you are right and I should have pointed that out that the double pulley is for 2 drive belts one for the left hand side and one to the right hand side if the pulleys rotate at the same speed as the main drive shaft which turns at I think a ratio of 4 to 1 then the outside valve shafts will look to turn at the right speed to the original design Ken Link to comment Share on other sites More sharing options...
Go_West Posted January 25, 2019 Author Share Posted January 25, 2019 /media/tinymce_upload/34cfe7715185a9e9c523473db54a485e.JPGThe parts have been installed on the engine which might make things a little clearer.By turning the wheels I managed to get the belt to drive the dummy valve shaft but only by crossing the belt to give it more contact on both the pulleys but as these are very oily engines I can see a problem with belt slip so even now this idea may not work as we still have the 2 shafts to build and a middle bearing block to connect the shafts down to the main driver and its gear box.Gears might be the answer any ideas?/media/tinymce_upload/0dae3f27d68de12ec41137e0ac62bc08.jpgThis picture shows the layout of the valve system and should it work the model valve drive will be covered by brass sheets as the picture here so you will only see the small shafts rotating down to the driver.In this picture you might just also see the drive coming off the third driver via a crank to the 2 oil pumps on the running board. This appears both sides of the engine./media/tinymce_upload/21629d8e9f256dea894f80ac24873cea.jpgWith the body in place the valve drive system has a nice lot of clearance with no problems there /media/tinymce_upload/71c7cc6fa6a98c8a9c36c4e79e4bce59.jpgI will carry on with the assemble of the valve system and try to run it on compressed air if that works then a steam test one thing will need changing is the bracket as this is not strong enough to take the load of the drive belt.I’m off to Lundy island to find the lost railway and 2 crashed Heinkel bombers so will not be online for a bit Ken Link to comment Share on other sites More sharing options...
96RAF Posted January 25, 2019 Share Posted January 25, 2019 Have a good trip Ken. Just been reading on line in the Daily Mail about a 1/8th scale Duchess - amazing, those running gear parts are more suited to my fingers.https://www.dailymail.co.uk/news/article-6629935/Model-train-took-10-YEARS-build-set-sell-record-breaking-200-000-auction.html Rob Link to comment Share on other sites More sharing options...
Rog RJ Posted January 25, 2019 Share Posted January 25, 2019 @ Gowest (Ken)"Gears might be the answer any ideas?"What about toothed belts? Link to comment Share on other sites More sharing options...
david_broad Posted January 31, 2019 Share Posted January 31, 2019 The second P2 Earl Marischal had the Holcroft / Gresley valve gear as per A1/ A3/A4 with the same nose as Cock of the North.On a Steam loco Poppet Valves allow the exhaust to be opened independently of the inlet, normally exhaust and inlet are part of the same slide or piston valve and operate together Cars don't use this feature as far as I know except maybe BMW valvetronic and F1 cars,, but the Internal Combustion engine is two stroke or four stroke while the Holcroft / Gresley syetem in common with about 98% of steam locos is double acting, or a 1 stroke. ( I think the Paget loco and Sentinel locos were the main exceptions being AFAIK single acting or 2 stroke. The big problem with Rotary cams was wear on the actual cams and it doesn't seem to have been until the BR std class 5 that this was solved. Piston or slide valve locos would have needed two valves and two sets of valve gear for each cylinder to achieve this. Link to comment Share on other sites More sharing options...
96RAF Posted January 31, 2019 Share Posted January 31, 2019 @ Gowest (Ken)"Gears might be the answer any ideas?"What about toothed belts? I was thinking simple friction drive but with all that steam oil about ther ewouldnt be any friction.Rob Link to comment Share on other sites More sharing options...
Go_West Posted February 2, 2019 Author Share Posted February 2, 2019 Rob/RAF96hiback now from our trip to Lundy and lots to think about and catch-up on toothed belt would be a great idea thanks so have ordered a 10 mm oil seal as most of these have a cercular spring in them to keep the seals lips in contact with the shaft So will take the spring out and see what size it is and if that will work.this would be like the drive for Mamod engines but like RAF has said there is lots of oil about and may still slit but would not be a problem with the heat. Link to comment Share on other sites More sharing options...
96RAF Posted February 2, 2019 Share Posted February 2, 2019 KenI am still not quite sure which bit of the fake valve gear you are trying to drive and where from and what happens after that. Is it the main drive or downstream over the wheels each side. I see the main valve drive belted to the outer auxiliary drives and that looks as if it will work but slippage could cause the ongoing bits to get out of synch. Will that matter. Gears or cogged belt (tiny and awkward to make) would give positive drive and keep the downstream bits working together If necessary. Could be onto something here - 3D printed metal micro gears.https://pin.it/bj5ci4q6y7tqjt Rob Link to comment Share on other sites More sharing options...
walkingthedog Posted February 2, 2019 Share Posted February 2, 2019 As it is basically a rotating rod, will it actually be noticeable on the moving loco? Link to comment Share on other sites More sharing options...
Go_West Posted February 2, 2019 Author Share Posted February 2, 2019 RAF96yes you are right about the drive it's the rotating shafts that go do to the driving wheels it is not the real drive for the valves just a dummy system both sides.WTD yes you are right at end of the day is it worth all the worrying and fiddling about no one will see it but as the out side valve gear on the flying Scotsman works in as much as it moves why not this engine the oil seal arrived to day in the post and its spring less would you believe it.more thought needed Link to comment Share on other sites More sharing options...
walkingthedog Posted February 3, 2019 Share Posted February 3, 2019 I fully understand your reason for doing it. You know it’s there and you want it to work. Perfectly reasonable. Link to comment Share on other sites More sharing options...
Go_West Posted February 3, 2019 Author Share Posted February 3, 2019 WTDI think I will build the rest of the parts and see if it is practical Link to comment Share on other sites More sharing options...
96RAF Posted February 4, 2019 Share Posted February 4, 2019 Ken see herecouplingshttps://www.micromark.com/Universal-Couplings-Set-Of-4_2Out of stock and maybe too big but the square drive and general principles could maybe be adopted.Rob Link to comment Share on other sites More sharing options...
Go_West Posted February 4, 2019 Author Share Posted February 4, 2019 Hi Robthats the sort of thing I'm hoping to create in the next day or two ken Link to comment Share on other sites More sharing options...
96RAF Posted February 4, 2019 Share Posted February 4, 2019 I remember the odd square drive universal you have on your tractor PTO Ken, which made me think it might scale down enough when I saw that advert. I also wondered if you could 3-D print onto an existing metal part to make those end fittings. A bit like dipping a matchstick in the red stuff to form a composite item.Rob Link to comment Share on other sites More sharing options...
Go_West Posted February 4, 2019 Author Share Posted February 4, 2019 Hi Robi don't think my 3D printer is up to that the idea I have in mind is more like a flat screwdriver blade and a slot the slot being the longer shaft might get a chance in the morning to make a start on a test model Link to comment Share on other sites More sharing options...
96RAF Posted February 4, 2019 Share Posted February 4, 2019 Sounds like a plan Ken.A typical motor/bogie cardan shaft has a cross like a filed down cross point screwdriver.There are some clever mechanisms to turn a right angle but nothing in the micro scale required here.https://pin.it/tqnsdekktao7wqRob Link to comment Share on other sites More sharing options...
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