To Hell With Reeds! Rotary Valve PiP. 

I’m on break and was upset when he hadn’t uploaded but then he followed through!

Very nicely put John, with dignity and resect.

Theres a lot of two stroke lovers, but even more two stroke haters 😂

@@abyssmanur3965 Mainly because the haters don't understand 2-strokes... they think they're "simple."

I'm a fan of both reed and disc valves. The reed has simplicity and the disc has that retro feel. Until a couple of weeks ago I had a A/C Piagio NRG Power test engine that's design is around 20 years old and was in it's standard road going form except for a clone 28mm carb and modified road going expansion chamber. After some TLC this engine could be held at 16200RPM under load on test for 10 second power runs until the piston skirt broke writing the engine off. The metal reed petals remained intact through it's road usage and over 2 hours of very high RPM testing. Lets hope Alex doesn't suffer with previous disc valve failure where the disc broke around the fixing flange. IMO there's plenty of work that still needs doing to the cylinder before it will work as intended. We'll all be here watching. Rock on Alex.

Hmm wasn't worth watching anyways 🥹

It (ground wheel drive) still eats HP, and probably more (due to a more complex drivetrain) than a more direct drive does. Ram air eats HP due to parasitic drag. There are no free rides, you have to produce the power your forced scavenging system eats, no matter how you source that power. Turbos have the advantage of using "waste energy" (dumped out the exhaust anyway) to power forced induction, though at the cost of reducing potential exhaust flow, and tossing all kinds of wrenches into exhaust pressure wave pulse scavenging in 2 strokes (running "on the pipe"). Then you have the potential road instability dropping a 3rd wheel could cause in your chassis dynamics. As above, "no free rides", every added complexity comes at a mechanical price somewhere in the machine equation. The "magic" is minimizing the price through efficient application of the potential power loss, reliably

Very true.

Also, stop pushing the machine. You aren't a volume business. If it runs an extra hour, who cares? Dial everything down, get good results the first time. Yes, as people that like performance, that is tough. However, it is the mature decision.

Yes, or servo.

IMO I feel the exhaust port will take some sorting. The transfers are easy to re structure with in reason. We mustn't forget the engine needs the torque as well as RPM. Lets not forget the old saying that holds true today as yesterday. "You have to get it out quicker than you put it in".

I feel like a large thrust bearing just smaller than the port, behind the valve disc would be the best way to reduce friction. As long as the disc is thick enough to minimize flex it would keep it from ever touching the outside wall at all. Also having the valve run at half engine speed with two cutouts instead of one would lower the surface speed to drastically reduce friction and make the disc a bit lighter, but it would also slow the opening and closing speed of the ports. But I don't know how important that is on a 2 stroke.

@Andrew Kay Those of us who have being on this journey for 6 years with Alex think it would be nice to see a conclusion before too long. It can be very frustrating when as Alex puts it " Failure after failure, why....why" Alex says he likes problem solving.

@Andrew Kay Yes "Binky" is a great project, but you can see the development progress from one episode to the next. If I was asked which was the best part I would say the SPX era right upto swiching over to RC fuel. It then went from reliable to fitting a 32mm carb to a 50cc

The cylinder currently in use is one I designed and got 3d printed in aluminium by Protolabs.

Actually been thinking abput exactly that, servo driven valve, rotary encoder on crank.

@@2STROKESTUFFING Servo crossed my mind but from the very little I know probably nowhere near fast enough, I was thinking literally just the rotary valve always spinning but driven but something like a drone motor. Lots ot electronics and someone clever with code but it could be a bit like an ignition map no idea if response time would be quick enough to alter duration on the fly but some of these drone motors are insane now. Might in some ways be less complicated than mechanical timing it.

@@mrln247 A servo could be geared up to achieve the right speed, torque shouldn't be a problem👍Adds complexity, in return you get complete control over timing, and freedom to mount the valve wherever.

@@2STROKESTUFFING I was thinking about gear reduction as drills have planet gearboxes, another way would be having multiple windows on the valve then if you where being clever you could change phase for blocks of rpm which would alter duration although I'm not saying I know how you would time that.

Base 12 is easily split up so could be 12:1 6:1 3:1 etc built in to the valve itself.