Reply to Thread

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Message: <blockquote data-quote="Dave70968" data-source="post: 3102008" data-attributes="member: 13624">So I correctly read the rotation, but I'm still unclear on the .050".  That's only 1/20", and every cam I've ever seen has lobes bigger than that, so is that .050" taller than the standard profile?  The link you provided also talked about 1.5:1 lifter arms, so that .050" looks like it only translates to .033" at the valve, which doesn't seem like much at all.As to 720° of rotation in a cycle, that means the space between TDC and BDC is 180°.  Is the "extra" open time on the intake before TDC (pushing exhaust back up the intake), after BDC (expelling good charge back up the intake), or both?  On exhaust, does it open before BDC (which would seem to be wasting part of the power stroke), stay open after TDC (which would seem to suck exhaust back in instead of a fresh charge), or both?  Or is there more at play that I don't understand that doesn't waste part of the charge one way or the other?For the aircraft carbs, have a look at <a href="https://www.aopa.org/news-and-media/all-news/2016/june/flight-training/how-it-works" target="_blank">https://www.aopa.org/news-and-media/all-news/2016/june/flight-training/how-it-works</a> and <a href="http://www.flight-mechanic.com/float-type-carburetors-mixture-control-system/" target="_blank">http://www.flight-mechanic.com/float-type-carburetors-mixture-control-system/</a> .  Aircraft carbs are supremely simple devices.  They're also smaller than most automotive carbs, no doubt because our engines don't produce nearly the power of auto engines.  You mention a 350 cubic inch plant producing an easy 400HP, and some going to 700; a 360 cubic inch aircraft engine will typically be in the 180-200HP range, and a 540-inch 6-cylinder typically tops out around 300 HP.  On the other hand, they cruise at 55%-75% power for hours, and are air-cooled, so there are some limitations there (also, weight is a serious limitation; an O-360 is typically going to come in at under 300lb; a quick check of Google puts the 350 Chevy at about double that).Edit to add: here's a quick overview of some commonly-available aircraft engines.  They're "Experimental" in that they're not certificated designs (everything in aviation has paperwork, and is built exactly the same way, or else is experimental and limited in what it can be used for), but are highly representative of the equivalent certificated design (in four-cylinder engines, Lycoming is the household name; in sixes, Lycoming and Continental are both common): <a href="http://www.superiorairparts.com/xp-series-engine/engine-models/" target="_blank">http://www.superiorairparts.com/xp-series-engine/engine-models/</a> .  Superior is a manufacturer down in Dallas that also makes some certificated parts, including cylinder assemblies (our cylinders are external and individually-removable).</blockquote>

Verification