[GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked)

[quote="Makr"]

Citation :

I will run a mechanical linkage to the left handlebar to open and close, and a spring loaded detent to secure the position.

just use an YPVS engine and a full prog CDI ( Ignitech or Zeeltronic ) and all will be as easy as it will work fine

[quote="SEB4LO"]

Makr a écrit:

Citation :

I will run a mechanical linkage to the left handlebar to open and close, and a spring loaded detent to secure the position.

just use an YPVS engine and a full prog CDI ( Ignitech or Zeeltronic ) and all will be as easy as it will work fine

Ah you suggesting he use the YPVS actuator to open the reeds? I guess that could work even without the ignitech, since the exhaust valve is useless in this application, and you'd want to open the reeds at about the same point as the exhaust valve would open...

i don't know ( didn't read all the text ) what he wants to move with his hands on the handle bar but whatever it is an ignitech and an YPVS engine will do the job and whatever the engine ( ie 400Rd ) ..... he will need an ignitech or zeeltronic

so to avoid issues on mecanical prehistoric device , just use it as it should be done as it's easy to do

SEB4LO a écrit:

i don't know ( didn't read all the text ) what he wants to move with his hands on the handle bar

You should, or you'll miss the point :)

Thanks for thinking of my saftey, but if that was my concern I wouldn't be racing a motorbike.


I don't need to remove my hand from the bar to move a lever.


This is old school two stroke. No exhaust/power/whatever valve to tie into.


Frits, thank you for your comments. I didn't know you were taking your24/7 idea down a specific avenue. I will step away.

Whaddaya mean, step away? I would be happy if you would use it for land speed .

Were any other factors taken into consideration in the design on the crankshaft except inertia?
For one you told us that it is counterproductive to rotate the cranshaft against the mixture flow.
(since the mixture in fully exposed to the crankshaft...)
Do you think a 24/7 idea can be utilized on a rotary base?

XpTpSMTT a écrit:

Were any other factors taken into consideration in the design on the crankshaft except inertia?

Of course. A crankshaft has so much more properties than just an inertia-value. This is the kind of simple question that needs a complete book to answer it.

Citation :

Do you think a 24/7 idea can be utilized on a rotary base?

take a look here: [Vous devez être inscrit et connecté pour voir ce lien]

Frits Overmars a écrit:

XpTpSMTT a écrit:

Were any other factors taken into consideration in the design on the crankshaft except inertia?

Of course. A crankshaft has so much more properties than just an inertia-value. This is the kind of simple question that needs a complete book to answer it.

Citation :

Do you think a 24/7 idea can be utilized on a rotary base?

take a look here: [Vous devez être inscrit et connecté pour voir ce lien]

I meant based on a rotary valve.

Didn't you click that link, Peter? Here is the quote I was trying to show you:

Frits Overmars a écrit:

...how do you build a rotary disk that stops in the open position when the engine revs reach the power band? I had no idea...
But then why would you need a rotary disk anyway? Because it flows better than a reed valve? That doesn't matter when you only need it to start the engine. And a reed valve is much simpler to open...

I presume someone has tried stacking two rotary valves that move relative to each other?

That would allow the closed-time to vary over a factor of almost 2... but controlling it while the whole thing is spinning at engine rpm would be... interesting :)

comme le flat 4 de rudi kurth ? (scissor discs)
ou tu parles de 2 discs qui tourne en meme direction ?

et pour le system ...interesting... une system centrifuge comme les ancien alumages


Est que ca peux marche si le couverture devant le disc peu etre decalé par une systeme de "moter de powervalve" ? ou meme deux plaques avant qui peux etre decale separement ?
(besoin d'une moter assie fort pour resister a une system de etanchetie plaque /carter)

rgdavid a écrit:

comme le flat 4 de rudi kurth ? (scissor discs)
ou tu parles de 2 discs qui tourne en meme direction ?

I'll spare the world the spectacle of two anglophones mutilating la langue française

No, to have a variable opening time they'd need to turn in the same sense. If eg you made ech of them
cover only 90° you could either have one immediately following the other (180° closed, 180° open)
or stacked completely on top of each other (90° closed, 270° open).

Moving the cover could vary the phase (open later & close later) but not change the total duration. Unless you moved the
opening radially and had the disc cut at an angle... but getting that to flow well would be a nightmare.

an excelent challenge all the same

i reckon you need 2 valve covers that move indipendently,

i'm gonna have to sit down with some cardboard templates to work this one out,

challange you to find a solution ? results in 2 weeks of head scratching ?

david,

[quote="Frits Overmars"]Didn't you click that link, Peter? Here is the quote I was trying to show you:

Frits Overmars a écrit:

...how do you build a rotary disk that stops in the open position when the engine revs reach the power band? I had no idea...
But then why would you need a rotary disk anyway? Because it flows better than a reed valve? That doesn't matter when you only need it to start the engine. And a reed valve is much simpler to open...

[/quote
actually I didnt...I thought......I thaw a puthy cat...um i mean.....
I thought I remembered everything.....
Ill have to go over and print for ease.
Also was trying to spawn a conversation.Although this is not the thread to do so.
"SOMEONE MUST BE THINKING WHAT I Am"......And Voila...(Thats where my french ends)
My experience in rotary valves is negligable or NIL.

GrahamB,rgdavid
A few years ago I serviced a RG400Γ..that got me thinking,now that RG has been abandoned
and in horrible condition...But I can have it and it got me
I am still looking for a single cylinder though for simlicity,but finding a rotary valve single here is imposible.
The 24/7 idea never occurred to me because I never experienced a bike working without reeds,
or with severly damaged ones.
My theory was something like a VVT for two strokes, give the nessesary timing at all engine speeds,
and probably eliminate reverse flow out of the carb.
Lets say something like reed valve but with control over opening time, without the drawbacks.
Racing technology must pass to production one time or another.

I have also thought about a system to variate the timing of rotary valves. I have an idea about a relatively simple way to adjust the timing of the rotary valve and I made some little drawings in MS Word.

Now I only have to post the images...

This is just a basic idea of how I think that (with two discs on top of each other) it wouldn't be too hard to make a variable rotary disc timing.

What do you guys think? Is this too simple to be true?

BTW, I'm just a 2-stroke enthousiast (well to be honest... I love everything that makes loud noise and produces power) and I only have very little "in the field" experience. The daily job takes way too much time and I have no-one to share the ideas with, let alone to accomplish them...

I love to read this tread and I hope to learn more of you guys!

Cheers

I like the idea about two rotary valves stacked.

But instead of rotating they could just oscillate back and forward controlled by a couple of fast and precise step/servo motors like the x and y mirror on an industrial engraving laser. The motors used to move the beam is very fast and accurate.

Then you would have fully programmable intel duration controlled by a combined ECU also controlling, ignition, exhaust valve, power jet and step motor for variable intake lenght.

Will start on a simple sketch of the layout.

Mic a écrit:

I like the idea about two rotary valves stacked. But instead of rotating they could just oscillate back and forward controlled by a couple of fast and precise step/servo motors like the x and y mirror on an industrial engraving laser. The motors used to move the beam is very fast and accurate. Then you would have fully programmable intel duration controlled by a combined ECU also controlling, ignition, exhaust valve, power jet and step motor for variable intake lenght. Will start on a simple sketch of the layout.

And while you are at it, maybe you can add a couple of camshafts, Mic .

@Hakkelaar: your proposal of shifting the phase of the disk by shifting the belt tensioners was used by Porsche over 20 years ago; it was their first version of a variable inlet camshaft drive.

Mic a écrit:

Will start on a simple sketch of the layout.

Maybe start with a calculation of the amount of torque required to move them back & forth at the required rate, and the power your stepper motor would need...

i would of thought 2 X valve covers that could be moved separtely,

but how to overcome the force needed to move the covers quickly against the resistance of oilseals or o-rings (or what ever to seal against air leaks)

After some more thinking one of the rotary discs could be removed.

One disc controlled by servo motor would be enough. It would still provide a good flow until fully opened and upon fully opened the flow is perfect.

Of course some calculations on torque requirements is needed. But I'm quite sure the motor speed is available based on the current design of galvano mirrors on lasers. But how much torque is need to overcome the friction caused by the suction and pressure on the disc is a good question.