Now this is really interesting, not only the port arrangement, but the manufacturing method as well!
It just happens I spoke briefly with a colleague about the possibility using laser-sintering/melting for cylinder prototyping. For me it will probably stay stay just like that, discussing and dreaming.
Anyway, his main concerns were surface accuracy and less than full density of the resulting material. That, and to find someone who had developed for an useable aluminium alloy.
-After seeing your cylinder today, the colleague said that it had some of, or even the best surface quality he had seen. Seems you have it all covered.
I think we have. We used AlSi12 material; the melting resolution was 20 micron. The result is a dense, hard workpiece, better than the best casting quality.
If there is a downside to all this, it would be that building these two 50 cc cylinders took 25 machine-hours; great for prototypes, but forget about mass production.
Neels van NieKerk auther of EngMod2T
As far as squish is concerned whether it helps or not depends on the residual turbulence at the time of combustion. As for squish quenching the flame at the edge of the squish band to stop detonation is not looking very likely. http://home.earthlink.net/~scloughn/id21.html
Tail pipe entry geometry http://www.google.co.nz/#sclient=psy...w=1024&bih=574
(2004) EngMod2T manual :- http://www.rddreams.com/neels/engmod2t.pdf
This manual is a bit dated but worth a look, hopefully someone can find a more recent version for us to look at.
Obtaining the EngMod2T suite of programs
The software price is $400.00. To purchase it email Neels van Niekerk at
vannik@mweb.co.za with a request. The software will then be emailed to you after which you
install it on your PC. The pre and post processors together with all the help files should then
work. EngMod2T requires a licence file to run. A one month evaluation license can be
provided. If after reading the help files you should decide to purchase the software contact
Neels van Niekerk to obtain banking details. Once proof of payment has been received the
licence file will be sent to you. The licence is for one computer only.
I know you are right. Women seem to always have something that requires conversation.
Question for Frits
With regards to adjustable length pipes For (Expansion chambers). I seem to have picked up that they at least mostly lengthening for low end power.
Has anyone tried ones that just shorten for top end or a least over rev potential to me that would be a more logical solution?( I am not always logical mind you)
I know Cagiva ran a hydraulic system and someone posted a solution you like on pit-lane but I can't access the pic I have a log in and it would let me in?
Last edited by husaberg; 8th November 2011 at 22:00. Reason: Question for Frits
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Kinky is using a feather. Perverted is using the whole chicken
You have to stay within certain length percentage limits for all elements of the exhaust system; you cannot make one part a lot longer or shorter in relation to the others without losing power somewhere.
It is best to concentrate on getting all dimensions correct for maximum power. In the high gears you don't ride low revs and in the low gears you'll have enough low-down power left to pull a wheelie or spin out the rear wheel (I'm not talking about buckets though, so you might want to reconsider your case).
If you have a decent setup for angle*areas, pipe, carburation and ignition, the necessary overrev potential will come naturally; no need to sacrifice maximum power in order to make it rev a little higher.
In my cylinders it was mainly the complicated cooling ducting that forced me to find a way around casting limitations. For an air-cooled cylinder like you want, there is no need to resort to selective laser melting.
Rob Metkemeijer's MB40 prototype engines are cast using the lost-wax method. Below you see a mold with exhaust and transfer cores, a wax cylinder and the end product. A mold like this for an air-cooled cylinder is relatively easy to make.
Was great catching up again. I think after being on track with the fast 2 strokes again. If it was dry it would have been a lot closer. The level of bikes and riders just keeps on climbing. I know that to win this race you need more than a fast bike. You need a fast bike a very focused rider and a bit of luck. Looking forward to next year already.
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That explains what we found (and suspected). We tried header and mid section extensions, neither on their own or in combination moved the power spread lower in the rpm range. The longer the extension the less top end power and a pronounced double hump. But no significant low end improvement.
And I suspect slippery pipes will behave much the same but water may work because I think it would change all the sections of the pipe proportionaly.
The power came back as the pipe was progressively shortened to its proper tuned length.
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