Model Engine Maker
Help! => Specific Engine Help => Topic started by: alm56 on December 16, 2016, 12:17:10 AM
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Hi Frends, I am (Trying ) to build my very first engine, Its a Flame Licker, I am at the point where I am ready to make the cam, I need to know ( All About) the slide valve timing, (To Let The Flame in) When it should start to open and close and anything else you think I may need to know.
Thank You All.
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One more picture
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Allen, unlike Stirling engines where the displacer and power pistons are normally 90 degrees out of phase, I am not sure the same can be said of flame lickers (or any exact degree setting for that matter). A lot is going to depend on the thermodynamic properties of the entire system, especially the cylinder. The best advice I can give is to make the timing as adjustable as possible so that you can hopefully find that "sweet" spot once you get it running, everything heated up, etc., meaning that the cam can be rotated. As you know, these engines can be very finicky and it may require a lot of trial and error.
Bill
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It seems like I saw some place that the the slide valve should open 20 degrees before the piston is at TDC, I don't know if that is true or not ? And I have no idea when ( What degree the slide valve should close) I just need to where to start ? So I can make a cam. :shrug:
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Allen, check out the plans for the Poppin Engine here: http://john-tom.com/MyPlans/SteamPlans3/poppin/Poppin-vacum-engSm.pdf . The cam for that engine should give you a starting place.
Bill
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OK, I sure will, Thank you Bill.
:ThumbsUp:
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Here is the plan I worked from for my first flame licker.
Ian S C
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The valve should open before TDC, about 20°, then the cylinder breathes flames on the downward stroke, and the valve should close just before BDC, this point has to be set while testing, say 10° before BDC to start, adjusting matters here.
after BDC, pressure decreases inside the cylinder upon cooling, up to less than atmospheric pressure, which pushes the piston back to top for about 90°, this is the motive phase, then as the volume decreases, pressure raises in the cylinder, hence the opening of the valve before TDC and the cycle continues, hopefully.
the closure of valve before BDC depends of lots of factors...
too early, the engine bounces, and cannot pass the BDC, a larger flywheel may help.
too late, air inside is not cooled enough after BDC to induce motive power.
You may appreciate the tiny power this cycle develops, hence the absolute requirement for free mechanical movements, coupled to a faultless air tightness.