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#31
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DIY Two-Stroke Engine
bod43 schreef:
www.deltahawk.com Too big for ultralight I would guess but seems like a very fine plan for a light aircraft engine. 160 hp and upwards V4 two stroke diesel. Yes yes, nice stuff though expensive. But the original question was about building one's engine from scratch. |
#32
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DIY Two-Stroke Engine
On Mar 9, 10:37*am, jan olieslagers
wrote: bod43 schreef: ... V4 two stroke diesel. Yes yes, nice stuff though expensive. But the original question was about building one's engine from scratch. After spray cans you want yet another safety rant? jsw |
#33
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DIY Two-Stroke Engine
Anna wrote:
Jim Wilkins wrote: On Mar 8, 11:55 pm, Tim Wescott wrote: ... www.deltahawk.com That link redirects to a poster site. Tim Wescott http://www.deltahawkengines.com/ Any day now..... jsw saw the price? 71 Thou $$$$$$ Not out of line for an engine that's capable of being certified but hasn't been yet. Aero engines are expensive. That's why folks go to great lengths to modify car engines to fly airplanes. When they're done, the engines are -- expensive. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |
#34
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DIY Two-Stroke Engine
Jim Wilkins wrote:
On Mar 9, 10:37 am, jan olieslagers wrote: bod43 schreef: ... V4 two stroke diesel. Yes yes, nice stuff though expensive. But the original question was about building one's engine from scratch. After spray cans you want yet another safety rant? jsw THAT, more than likely, just won't happen. Fred Blanton did it. But it took his entire adult life time. So this thread is about TALKING about building and engine from scratch. Not actually building one... -- Richard Lamb http://www.home.earthlink.net/~cavelamb/ |
#35
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DIY Two-Stroke Engine
cavelamb wrote:
Jim Wilkins wrote: On Mar 9, 10:37 am, jan olieslagers wrote: bod43 schreef: ... V4 two stroke diesel. Yes yes, nice stuff though expensive. But the original question was about building one's engine from scratch. After spray cans you want yet another safety rant? jsw THAT, more than likely, just won't happen. Fred Blanton did it. But it took his entire adult life time. So this thread is about TALKING about building and engine from scratch. Not actually building one... Henry Ford did it, in his garage, over the space of a year or two. But the performance wasn't high. The Wright Brothers did it, over the space of a year or two, and even though the performance wasn't high it was still good enough! Talking about building stuff can get you a lot more bang for the buck than actually doing it. Witness me, with several engine parts sitting next to a lathe that's been idle for days, and last had an accessory for a completely different engine built on it, not a part for the engine that's half-done and sitting next to it. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |
#36
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DIY Two-Stroke Engine
durabol wrote:
For the last few years I have toyed with the idea of building a homemade two-stroke engine for UL use. What keyed my interest was reading about homemade model aircraft engines and reading and watching a re-enactment of the Wright brother's first flight with a replica engine (not a two-stroke engine). Has anyone made a 2-stroke engine from scratch? One may need to cast aluminium, may need a lathe and milling machine with boring head and hone or perhaps the boring and honing of the cylinder and bearing journals could be farmed out. A commercial carburetor and piston could be used. Two-stroke engines seem simple enough that home construction may be possible, if not practical. A direct drive engine will be that much heavier when you take into account the weight of the drive reduction system. I have calculated the weight of an 80x80mm bore and stroke 2 cylinder opposed engine and it was a bit under 40lbs which should give about 1hp/lbs. I used 10mm cylinder and crankcase wall thickness and a 1.25" dia crank. I have got some idea of port-time-area from the freeware computer program called "BiMotion". I'm not sure how good the data is for lowish speed engines but I guess it is a start. I have also worked up a spreadsheet for similar information. I don't think a reed valve system is needed for this engine since it is only going to operate at a fairly narrow rpm range and the port timing isn't critical. Piston ported valves offer similar performance to other induction types but only over a narrow rpm range which is what I have planned for the engine. I plan to build an engine with a restrictive exhaust to ensure no fuel escapes. I have heard that piston ported engines can spit some fuel out of the carb at idle but this doesn't seem like a major problem. Rotary valves via crank shaft induction (disk or drum valves as well) is an interesting idea but I don't think I need the critical timing they provide. I was planning on using the largest two-stroke piston (not a diesel piston) I could find and using the largest stoke that was reasonable, something like 90x105mm Brock http://www.s363.com/Elbridge/aee.html -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |
#37
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DIY Two-Stroke Engine
Tim Wescott wrote:
cavelamb wrote: Jim Wilkins wrote: On Mar 9, 10:37 am, jan olieslagers wrote: bod43 schreef: ... V4 two stroke diesel. Yes yes, nice stuff though expensive. But the original question was about building one's engine from scratch. After spray cans you want yet another safety rant? jsw THAT, more than likely, just won't happen. Fred Blanton did it. But it took his entire adult life time. So this thread is about TALKING about building and engine from scratch. Not actually building one... Henry Ford did it, in his garage, over the space of a year or two. But the performance wasn't high. The Wright Brothers did it, over the space of a year or two, and even though the performance wasn't high it was still good enough! Talking about building stuff can get you a lot more bang for the buck than actually doing it. Witness me, with several engine parts sitting next to a lathe that's been idle for days, and last had an accessory for a completely different engine built on it, not a part for the engine that's half-done and sitting next to it. Yep! Tha's how it happens... -- Richard Lamb http://www.home.earthlink.net/~cavelamb/ |
#38
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DIY Two-Stroke Engine
This isn't aviation related but this guy built a replica of a 1919
motorcycle. The info on the work involved is well worth reading... http://www.flashbackfab.com/pages/excel00.html Tony |
#39
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DIY Two-Stroke Engine
On Tue, 9 Mar 2010 04:36:58 -0800 (PST), Jim Wilkins
wrote: On Mar 8, 11:55Â*pm, Tim Wescott wrote: ... www.deltahawk.com That link redirects to a poster site. Tim Wescott http://www.deltahawkengines.com/ Any day now..... jsw For the last 10 years. |
#40
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DIY Two-Stroke Engine
"Peter Fairbrother" wrote Without knowing anything much about ultralights (beyond they look fun but dangerous) wouldn't the obvious source of lightweight engines in that power range be motorcycle engines? You would think, but how they are designed is a major problem. Most have the gearbox made as one with the lower crankcase. You can't get the weight off of the engine, and the gears in the bike tranny are not tough enough to run a prop, so you have to live with the weight and figure out a way to get the power out of the case without using the gearbox. Big problem. -- Jim in NC |
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