FILENAMES: Merlin_blocks_c.jpg Merlin_Crankcase_bottom_1.jpg Merlin_Crankcase_front_1.jpg Merlin_Crankcase_Parts_1.jpg Merlin_Vac_Chamber.jpg Merlin_Wax_Cyl_Block.jpg Merlin_Cyl_Hd_Wood_a.jpg Merlin_Cyl_Hd_Wood_b.jpg Merlin_Cyl_Hd_Wood_c.jpg Merlin_Cyl_Hd_Wood_e.jpg Merlin_Cyl_Hd_Wood_f.jpg Merlin_Cyl_Hd_Wood_g.jpg Merlin_Cyl_Hd_Wood_h.jpg DESCRIPTION: These are pictures of a model Merlin engine as it was being built. Posted by Tom Kay . Tom provided the following description: ================================================================= These are some pictures of my quarter scale Rolls Merlin parts and patterns. As you can see, there's not a whole lot to show yet, but this might interest of few of you. The Vacuum chamber is made out of a swimming pool filter with a 1/2 inch polycarbonate window. At 25 inches of mercury, the window, which is 24 inches ID, bows in about 2 inches. The vac chamber will be used for surrounding my wood patterns with RTV rubber, then pouring wax into the rubber molds, then surrounding the wax patterns with investment material from Ranson and Randolph. That's the plan, anyway, and at all three steps, the vac chamber will help me keep air bubbles out of the whole picture. The wood coloured pattern is the crankcase of the Merlin and I made the front reduction gear case in a separate piece, so I can pull the hardened rubber mold off the front without getting it stuck. The I'll pour the 2 wax parts and join them, just like the wood pieces. The metal shown, (this is a metal working website !!) is the first set of cylinder block from an Aerospace foundry in Montreal. They did them for free, and who can pass that up? The wax and white pieces of wood are patterns from the cylinder block (minus the head). So the next part to be cast in wax, then metal will be the crankcase. I am working on the cylinder heads (just started) and just this weekend I brought home a full wheelcase and supercharger from a friend who has a few Merlins rusting on his farm. I have already unbolted the wheelcase from the supercharger and I can't belive how easily it came apart given how all these parts have been stored. This project will take me about 4 lifetimes to complete. It's a very interesting journey for me, and I enjoy sharing the results with others, engine builders or not. I am in touch with others who build engines, and anyone can feel free to write. Keep it clean ! I work at a government facility ! Cheers, Tom Kay, Ottawa. tom.kay@nrc.ca --- Dear Sir(s) at Metalworking: Here is another set of pictures for the drop box. Please let me know if I am sending too many ! I don't wish to overload your system. These are pictures of a wood pattern of a 1/4 scale Rolls Merlin engine, cylinder head. The pattern is not quite finished (but close) and this is an opportune time to see how it's being made. I use several layers of bass wood, and this layering allows me to carve all of the intake and exhaust ports to the right shape, as well as the internal coolant passages. The actual wood pieces will be glued together into 2 main pieces, upper and lower, then used to make 2 silicone rubber (RTV) molds, and this will accept melted wax. The 2 main pieces of wax, upper and lower cylinder head portions, will be glued or melted together to form one unit, basically a hollow wax cylinder head. There will be lots of core vents, so that the internal investment core will be held firmly in place by the outside investment. Then the wax will be invested, with vacuum assist to help push the investment into all the internal nooks and crannies, and sent to an aluminum foundry. I've not done this yet, but I am hoping for success with the vacuum method. I hope this is interesting to others who are making mini engines. If anyone has questions or comments, feel free to send or post them. --- Hi Engine Enthusiasts: There are a few new pictures of my 1/4 scale Merlin in the metalworking website. Just look in the dropbox, under "Merlin" and you'll see them. The new ones are the "Cyl Hd Wood" and these are pictures of the wood pattern I am making of the left cylinder head. Then I make rubber molds, pour the wax, and finally get to the metal stage. If all goes well. As you can see, it's painstaking work, but fun also. I was not sure at first how I'd make the internal coolant cores and intake/exhaust ports of the cylinder head, but I think the method shown, with several layers of wood, will work. I'll know as soon as I make the rubber molds and pour my first wax. To minimize damaging bubbles, all pouring and investing will be done in a vacuum chamber (an old swimming pool filter tank). If you have any questions/comments, please write or post them. Cheers, Tom Kay, Ottawa. tom.kay@nrc.ca