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    PatRoVa Rotary Valve engine

    The simply genius aspect of a poppet valve is, that it does not move on the sealing surface when exposed to the maximum pressure of hot combustion gas. It stands still. The second genius aspect is, that the hot exhaust gasses do not pass an oil film at any time with high velocity. In fact, the...
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    Duke engines

    There have been barrel-engines for over 100 years now. They all share difficult lubrication conditions, difficult thermal conditions, extra tight tolerances and lack space for maintenance. In other words: These are expensive to make, have a short lifespan and expensive maintenance. I don't...
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    Casting con rods

    The conrods in real engines are made of (forged) steel, because the weak E-Modul (Youngs Modulum) of aluminium won't allow for stiff supporting structures around the bearing bushes. The bushing will deform and thus wear out quickly. This is unimportant in model engines. For illustration...
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    Compression Ratio, Cad Assist

    Cr = ( 9953 + 1058 ) / 1058 = 10.4
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    Using shims to tram a X2 mill

    Use a compound (polymer resin with a high percentage of metalpowder for enforcement ) specially made for that purpose such as Diamant Metallplastic DHW to provide force-fit cover on the whole mating area. You can use WD40 as a parting agent for most products (check this prior to use!).
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    Future small aircraft engines.Wich way?

    Well there are already small power plants established to supply trucks, especially for the refrigeration units (at least in Europe they are). So they clearly aimed at the military market. Military? Funding comes from the taxpayer → if there’s a problem, continue to throw money at it until...
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    Future small aircraft engines.Wich way?

    Niels, that crankshaft design will wobble unter load conditions because of the bearing layout. There will be lots of undesireble sideeffects, including periodic noise (and wear) of the bevel gears. And I think that the amount of power supplied to each prop is not equivalent (at least with...
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    Future small aircraft engines.Wich way?

    This is a pipe dream. It will be expensive to develop and to purchase because of the small lot size. Plus engines with hot exhaust gasses passing hot, well lubricated parts such as piston rings will never meet emission standards. If there’s is any future for new small aircraft in the...
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    Engine bore/stroke ratios

    Lubrication oil and manufacturing techniques made great improvements over the centuries. Steam engines were built for industrial work and had to be reliable for a long time. Lubrication was a great problem for decades. To tackle this problem in a piston engine, you’ll have to reduce the...
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    More CAD Options.

    Yes that's the usual way in every cad program. Elements on the screen must be defined precisely so the program can create unambiguous data you can perform operations with later. I recommend using one of the big established cad-programs, too (if you can afford it). Here are some reasons for...
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    More CAD Options.

    Even the objects are called solid, they aren't. They are made of surfaces, the programm calculates the boundaries and hides everything outside of the boundaries. The solids are hollow. Hide one of the faces and you can have a look inside. I installed the programm some time ago but never...
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    It is there, but you've accidently typed your text in between the
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    Drawing selling and such

    In most countries it depends on whether you sell it from your private use property or from your commercial use property. You usually buy a license to build one (or several) piece(s) of xyz and this includes using the plans. As a commercial user, you’re usually not allowed to pass...
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    Please help!! Silver soldering/brazing confusion

    Cheap electric cooktops (the ones with a cable attached) are getting red hot if left at maximum for some time. I use one of the white ones like these for heating up the workpiece when...
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    The picture on top of the page is a featured user project, called "project of the month". In the past the picture had a link to the nomination thread which obviously is absent now. Maybe Austin can fix this? The engine is a Hoglet and you’ll find plenty of information on the net and...
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    Alternative cranks

    Regarding power: Let’s assume that the amount of obtainable energy in the combustion gasses, which is applied to the piston, is a fixed amount in total. A mechanism is a like black box. All energies that go in must come out again somewhere. If you install a “black box” in...
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    hitorque lathe high torque!

    Edit: I mixed up the loose side of the belt.
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    V12 Build

    There's a tiny bit of information on wikipedia, too: So the smaller rods are called slave rods.
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    Do I go single or multiple?

    If you build it to actually power something, eg a RC-Plane, other points such as proper lubrication, cooling, ignition and reliability become more difficult to archive.
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    V12 Build

    gbritnell is right. If you attach the small linked rod somewere off the center of the master rod, the linked point is not on a circle, but on a oval path. Thus the pistons on the linked rods have different strokes and the timing is different, too. The piston reaches top dead center when the...