ESE's works engine tuner

[Frits Overmars]

...Prior to the current KF and KZ engines, there were the 100 cc direct drive engines, the last ones featured a tri exhaust and A and C transfers. These revved from 7k to 22k (pretty much self-destruct levels at this speed). The exhausts were a compromise between max power and a useful power spread. It would be interesting to see a power curve of one of these. Husa, where are you?

No need to disturb Husa. Here is a comparison of the Aprilia RSA125, a TM 6-speed 125 cc kart engine and a world championship-winning 100 cc direct-drive kart engine.

Acceleration with respect to crank angle . Formula within this link. http://en.wikipedia.org/wiki/Piston_motion_equations

This wiki-article describes a crank mechanism, not an engine. For our purposes there are several factors missing that are by no means negligible, like crankshaft inertia and gas pressure.

[ken seeber]

No need to disturb Husa. Here is a comparison of the Aprilia RSA125, a TM 6-speed 125 cc kart engine and a world championship-winning 100 cc direct-drive kart engine.

Neat comparison. The 100s did pretty well, given the fixed ratio & power spread required.

Moooooooool's figures tell a bit of a story:

At 12000rpm - 42620 m/s^2
At 17000rpm - 85537 m/s^2
At 30000rpm - 266378 m/s^2

Forces at 30k are 6.33 times that at 12k. That means that whatever gizmo/mechanism that Mr Ryger has down there, it must be pretty good = robust. Centrifugal loadings are 6.25 times, so there must be lots of strength down there.
Maybe, if there's someone over there, could they shoot down to the Czech patents office and get this thing to go thru quicker ? Can't wait.

[husaberg]

No need to disturb Husa. Here is a comparison of the Aprilia RSA125, a TM 6-speed 125 cc kart engine and a world championship-winning 100 cc direct-drive kart engine.


This wiki-article describes a crank mechanism, not an engine. For our purposes there are several factors missing that are by no means negligible, like crankshaft inertia and gas pressure.

Hey..........that's my job
I was looking for that pic the other day, I think it was on Pitlane. I tried looking in your pics posted here prior and I couldn't find it, or missed it.
Gas pressure is an interesting one
While there are rules vs forced induction I am not sure if they really cover creating vacuums .......
I did a large post a while ago but I lost in in Cyber space (my fault)regarding the 1/3 rule for additional pressure and some stuff Jennings and the Japanese sae papers re primary compression.

I was musing if the peak of low pressure controlled flow displaced only by the piston pipe and large efficient crankcase relying solely on pipe and port resonance had been reached it zenith.
I also mused that if one could pre-compress the contents of the cylinder or crankcase there would be more time for flow.
Transfer design exhaust timing control have moved ahead a lot since the sixties. Also with a separate crankcase maybe a variable size electronic flow control fuel injection and intercooling.
Mixed in with some clever high speed low friction crankshaft without low drag.

https://youtu.be/98Vkl1YnNFs
https://youtu.be/-cCt9JobjOg
https://youtu.be/cJDM_g4Wl2s
https://youtu.be/aF92B6Gon3M
https://youtu.be/WTt_hoWtMIc
https://youtu.be/mkQ2pXkYjRM

To me Whether the Ryger fits the current rules is irrelevant, if it is clean and fast and simple its a winner in my eyes.
Who need the FIM or Karting bodies if it was legal and too fast it would only be handicapped or banned regardless, look at the 125/250/500 GP bikes as examples of that

[teriks]

I'd be very interested in seeing how you built the internals of that silencer if you were happy to share.
Thanks for posting the photos. I love seeing where else 2 strokes excel in this world.

Better late than never..

Nothing fancy, but does the job good enough to comply with the rules for F3D racing with good margin.

[Frits Overmars]

To me whether the Ryger fits the current rules is irrelevant, if it is clean and fast and simple its a winner in my eyes.

We're on the same page Husa. The Rygers amazing power and its willingness to rev are not even its main strong points. Its fuel economy and clean exhaust are.
But the environmental climate is not favourable for two-strokes.
Several dutch cities are contemplating a ban on small two-strokes because they are big polluters. Which is true because these 50 cc mopeds and scooters are limited to 25 or 40 kmh. They are not allowed to produce anything like decent power, so their combustion is mediocre.
The logical error is of course that vehicles should be banned if they pollute, not because they are chinese, or orange, or two-strokes. But try telling that to a politician.
The only thing they understand is what the public wants to hear. They don't want to see 'clean' and 'two-stroke' in the same sentence.

[Haufen]

The Rygers amazing power and its willingness to rev are not even its main strong points. Its fuel economy and clean exhaust are.

As HP and rpm have been published, are there numbers regarding fuel economy and clean exhaust available that can be published, too?
Like best point BSFC (g/kWh), and emissions wise BSHC (g/kWh) and BSNOx (g/kWh)?

[Frits Overmars]

As HP and rpm have been published, are there numbers regarding fuel economy and clean exhaust available that can be published, too? Like best point BSFC (g/kWh), and emissions wise BSHC (g/kWh) and BSNOx (g/kWh)?

The numbers are there, but not yet free for publishing, I'm told.

[Haufen]

The numbers are there, but not yet free for publishing, I'm told.

I am looking forward to that!

Are you allowed to tell us why it is clean / which basic mechanism is behind this? As far as I understood it is not burning 2T oil. Anything else?

[Frits Overmars]

Are you allowed to tell us why it is clean / which basic mechanism is behind this?

[Grumph]

I am looking forward to that!

Are you allowed to tell us why it is clean / which basic mechanism is behind this? As far as I understood it is not burning 2T oil. Anything else?

It's presumably burning the mixture more completely. Which raises more questions - better air/fuel mixing ? leaner mixtures ? does the head even have squish as squish is known to do bad things to emissions.
Sorry, I don't have any answers, still feeling around the bottom of the bed....Ouch, it was a cat....

[sonic_v]

This guy appears to have done a lot of engineering on this project

https://nl.linkedin.com/in/lennartvandendoel

[breezy]

The problem as I see it is twofold.
If you are talking what we regard as "normal" engine technology with rods etc, and these were converted to plain bearing, the next weakest link in line is the ring seal.
At 30,000 and approaching tdc, the ring inertia would easily overcome the gas pressure trying to push down on the ring seal surface.
Then the next issue is simply time,and with what we regard as "normal " pressure ratios across "normal " ports there is no way of achieving any meaningful flow quantity
in the time allotted.
Thus yes, some form of additional time/area is needed or some form of increased pressure differential generation, over and above that created by the virtual supercharger we have inside the pipe.
This is where we are at right now with the new engine being discussed - it must have a non "normal " movement translation device under the piston to achieve 30,000,it must have a different
bore seal arrangement, and it must have some form of additional "supercharge" to achieve 70Hp at 17,000.

thanks for your feedback.. to be honest im a bit reluctant to even bother thinking about engine tuning with this Ryger situation looming overhead,i could be wasting time, money and energy. lets just hope it comes into the public domain.

[F5 Dave]

I don't think they are going to be selling magic filter canisters soon. Besides it will take an age to tool up for those flip top pistons in the size you want.

[Frits Overmars]

I can see that the questions will keep coming. I don't mind at all, it fact I enjoy it, but it's a little tiresome having to repeat over and over that I cannot answer all of 'm.
So here's the deal: you can ask anything you want and if you don't get an answer, you may assume that I did read your question but that the non-disclosure agreement does not allow me to answer.

[ken seeber]

It's presumably burning the mixture more completely. Which raises more questions - better air/fuel mixing ? leaner mixtures ? does the head even have squish as squish is known to do bad things to emissions.
Sorry, I don't have any answers, still feeling around the bottom of the bed....Ouch, it was a cat....

The key to fundamentally reducing fuel consumption (and unburnt HC emissions) is to prevent the fresh mixture escaping into the exhaust and out to atmosphere.
4Ts do it by separating the exhaust and inlet cycles. 2Ts achieve this by either injecting the fuel into the cylinder after exhaust port closure or:
1. Transferring the charge at a time when the exhaust port is closed
2. Transferring the charge at a time when the fuel cannot escape out the exhaust, say, by having to travel a long path
3. Ensuring that any charge that has passed out the exhaust has been returned into the cylinder.

So, as the Ryger is running the standard exhaust, it is doubtful 3. can be well controlled. So, from what I can see, it's either 1. or 2. Could have missed something maybe?

As a total aside, at Orbital ages ago, we set up a motoring rig and on this was a 4cyl 4T engine, but no head. At 2 - 3k rpm, oil was collecting on top of piston. Stop it, wipe it, re-run it and the same. My conclusion from that was that while oil control rings are very important, some form of high pressure above the piston during the cycle is further necessary to prevent oil migrating upwards to above the piston. So, given the Ryger doesn't use oil, say no more than a 4T, then either its piston or rod or mechanism must at least be subject to a positive pumping pressure.