Forum whore
I too would pick the epicycloid for simplicity and revs, and for the possibility to build an opposed twin with very few extra parts, or use the other end of the con rod for other means, pumping for example.
The beam crank does allow compression ratio variation, but unlike your small double-rpm HCCI crank, the pressure rise may be too slow for good control.
Hardcore Biker
Breezy, there are 3 expectation or reasons for trying this:Originally Posted by breezy
1. High output (read road racing) 2 strokes can suffer from severe detonation at high revs and small throttle openings when the scavenging pressure that was lower than the cylinder pressure at transfer opening, so a lot of hot spent gases entered the transfer ducts and heated the fresh mixture even before it was compressed in the cylinder.
2. Essentially the design provides what is known as “variable valve timing”, which in this case will allow the exhaust system to work over a wider rev range, giving a wider powerband.
3. At low loads and speeds it will offer a much more stable scavenging stream (due to the higher velocity obtainable with the much lower ports) offering improved “cycle to cycle” combustion event stability, ideally it will be a 2 stroke that 2 strokes at idle. This implies a significant reduction in HCs and fuel consumption
Time will tell. I suppose I'd bettter get on to making some more bits, but been a bit distracted with Fletto's strippers.
still basking in the glory..
Do we know what range of compression ratios are required to initiate and sustain hcci running with just low grade pump fuel? would anyone know if the nitrogen expelled from normal combustion be the same as that added to increase performance in race car engines?
i liked the spark plug link, posted earlier in the thread, think used in f1 engines. small amount of fuel combusted to provide heat to initiate /control better combustion of the remaining fuel charge, perhaps pre combustion area in cylinder head .
Hardcore Biker
Slider report. Piston done and shortened. Note, as the transfers occupy all the real estate at BDC, the piston cane be shortened, something that had to be done anyway to provide a sufficient flow path area from inside the piston and the crank/crankcase when at BDC.
With the cylinder plated, the head, which spigots into the bore of the sliding cylinder and also guide it, could be turned down to a sliding fit within the bore. Then, with some old and dodgy radius turning gizmo I had, was able to shape the head to suit the 100 radius of the piston. This will be continued to be cut to provide the target 0.07 squish clearance. After this, the actual bowl can be machined in.
Stripper update. Can’t say.NICE, now you stay in that workshop until it makes noise out the exhaust! OK. Tell the wife you have strippers at work and can't come home or something, anything, just make it go. We can't wait.
L-Plate Rider
Flettner or anyone who has been getting started with castings I have been looking at getting a few books. Any chance you've read or heard of: The Complete Handbook of Sand Casting, Metal Casting: A Sand Casting Manual for the Small Foundry, Vol. 1 and 2? If not I'll, probably order anyway and report back!
https://www.amazon.com/dp/083061043X...I371EZZWYS0KUL
https://www.amazon.com/dp/0970220324...I36ESQ3SSQ3QAI
https://www.amazon.com/dp/0970220332...I1BD8Y316F8WCJ
Thanks,
Paul
Forum whore
Yes they all look like good books, worth reading I'm sure.
I was lucky enough to work in a foundry for a while and along side a very experienced pattern maker, taught me a lot.
Paul, nice bike by the way (the H2)
Anorak
Another one Paul
https://c2249bf946246ad88d7d22cd7f15...f-download.pdf
https://www.scribd.com/doc/127045351...ckyard-Foundry
Kinky is using a feather. Perverted is using the whole chicken
Forum whore
Castings back from Neal's Foundry.
Bogeyman
They look all right Neil, not bad turn around either.
Price was OK?
Go soothingly on the grease mud, as there lurks the skid demon
L-Plate Rider
Thanks Husaberg!
L-Plate Rider
Thanks Neil. I fancy making a modern triple at some point. I finally got a workshop so I can get on with all the projects and try to catch up to you and others doing interesting work!
Forum whore
Me too, I've been pondering over a modern triple myself. Every time I get enthusiastic I remember all the unfinished projects
But In saying that I do have an interested party that want's one (as well as me) so the design process continues. First it was going to be a 1050cc three using my own cylinders off the 700 twin gyro engine, but then it got down graded to a 700 twin (with a balance shaft). BUT now it's down graded again to 480 three. I'm building a 160cc (58 x 58 ) cylinder to suit this bottom end bolted in the YZ250 frame, with just standard, modern, port arrangement (two versions, one a bridged port and one a single with eye ports). So three times 160 cylinders but in a line? Firing the two outside cylinders together and the middle one 180 degrees later, (better for mechanical balance) or turn it into a V?
I'm keen on the three in line as it will be easier to make, center cylinder pointing backwards, water cooled cases, possible EFI too.
But this is all just dream land at the moment.
You know I do have these patterns here for a rotary valve 700 tandem twin engine (ex gyro engine ), can't help day dreaming about that as a street bike. Thin and lite, goobs of power
Might be 153cc, not 160cc opps.
Forum whore
I couldn't wait so I got them to send the casting back to me, yes they were fast turn around. The finish is ok I have seen better but will be fine for what it's doing. Cost, well, I guess they need to stay in business but I did think @ $90 each was on the high end (plus GST) perhaps I'm just a tight old bastard.
So I'm still heading down your way this weekend, might take you up on that beer.
Anorak
http://www.motohistory.net/news2009/news-oct09.html
Some rotary valve engines I have never seen.
Kinky is using a feather. Perverted is using the whole chicken
Bogeyman
No worries, give me a call when it's beer time.
Go soothingly on the grease mud, as there lurks the skid demon
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