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    Twingle engine

    I'm really late to the party (actually I was looking for Twingle plans on the web and found this). What may not be apparent in the drawing is that a single, rocking connecting rod will bind if the attachment to crank and wrist pins is perfectly rigid. That's because the paths described by the...
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    Ignition system for Farm Boy

    Don't buy electronic components off of eBay (Sorry @doc1955) At least not common chips like the 555 -- you can get them cheaply from real mail-order suppliers. DigiKey, Mouser and Newark in the US, Farnell (I think) in the UK. Counterfeit chips are a thing, you can trust a distributor, and it...
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    Geared horizontal twin engine

    If I were the same guy who came up with all the bitty parts in the Citroen DS suspension, or whoever it was at Bristol that decided that a 9-cylinder radial engine should all the complication of sleeve valves (all those gears!) instead of a couple of bump rings, roller lifters and tappets, I'd...
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    Geared horizontal twin engine

    I feel like it's too late for this comment since you're already commencing work -- but if you put the valves on the bottom and the power cylinders on the top, you'll be driving the flywheels with the crankshaft without any major changes to the rest of the engine. (Well, aside from making it...
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    fuel mixture issues. stuart 400 replica build.

    Y'know, everyone motivates themselves differently. But if I were in your shoes and started despairing that the thing would ever run, I think I'd try gasoline (or ether!) just to make sure that the rest of the engine is functioning correctly. Once I'd verified that the only salient problem is...
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    LTD Stirling

    So, to solve a problem with figuring out how to hold the work in my Smithy in milling mode, I decided I'm going to trepan a slot in the bearing block, and make a matching dingus in the post. I've just trepanned something for the first time ever! And made a trepanning tool for the first time...
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    LTD Stirling

    Hah! I put it in an electric skillet set to 350F (probably way hotter than necessary, and only as I write this do the words "temper" and "draw" zip through my brain), and it popped right out. Next time I won't get it so warm, if there even needs to be a next time.
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    LTD Stirling

    I'm quite happy. I inherited a bunch of mechanical and electrical and electromechanical doodads from my Uncle, who passed away 30 years ago. In all the stuff is a little tube with some very sweet little bearings, 3/16" ID, 5/16" OD, and about 0.110" long. I'm going to use these to support the...
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    Ignition system for Farm Boy

    You could always go with a Kettering (points, condenser & coil)! That's pretty easy.
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    Nalon Viper 2.5cc CI Engine

    @Ramon You could use a wavy washer to spring-load the thing. Or maybe a really skinny Belleville washer. Even once you're past the need for it to be custom-made, I can see all sorts of difficulties with getting the material and temper right so that it stands up under heat cycling and...
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    Nalon Viper 2.5cc CI Engine

    Tug, if I'm understanding what you're saying correctly, should you also be recommending that the front housing be fit so that the outer race can move fore and aft, to find its own happy place? Because otherwise it could end up loading the balls against the races just by how its positioned in...
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    LTD Stirling

    Two nominally nice plates. I say "nominally" because the second one is a bit - uh - not flat. It's probably within about 0.01 or maybe even 0.005 now, though. The sheet that I cut this from was banged up in one corner, and I think that wow extended into the circle there. Fortunately, I have...
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    LTD Stirling

    One plate, 4.497" in diameter -- I keep hitting these things a bit small! The other plate, ready to be tossed into the 4-jaw. I'm using double-stick tape to hold the plate to the round bit of plywood that I'm using as a chuckable piece.
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    LTD Stirling

    Top and bottom plates. Made from some scrap aluminum sheet that I got God knows where. I'm going to see if I can turn these into nice round four and a half inch diameter circles. I don't know if I'm going to keep the wood grain or if I'm going to try to remove it. I'm sure it's going to...
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    ENV aero engine project

    I worked for a company building infrared cameras. we used a part that was electroformed by plating copper onto an aluminum form and then dissolving the form with acid. So it's certainly a known production process for making intricate shapes out of easily-plated metal like copper. I'm not sure...
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    LTD Stirling

    So where you you source a hunk of graphite for a power piston? I'm tempted to start out with an aluminum piston and some graphite lubricant.
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    LTD Stirling

    It's a displacer cylinder! It was supposed to come out one inch long, but it's about five mils short. I'm going to keep it.
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    ENV aero engine project

    I think you should anchor it to an ultralight that can fly on five or ten horsepower, and then do the obvious!
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    ENV aero engine project

    Oh, the sound is amazing! I love it.
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    New to machining all the toys no knowledge.

    I have a lot of scrap, bought by the pound at the local scrap yard. Some of it came stamped with the alloy (i.e, I know my 6061 is that, because it says so). Some of it is mysterious, ranging from what appears to be 4041 steel to some really high-alloy stuff that's a pain to machine that I...
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