Forced induction 100cc

[Sketchy_Racer]

Sketch, thats a realy interesting post ......

Thanks Rob,

Probably out of reach but will still be of interest to you is a traction drive CVT



If you google Nuvinci they make a CVT for a bicycle which is really neat, not sure how they control the gear ratios but it is a nice little unit.

There is a lot of different designs of traction drive CVT but the one in the video has to be one of the best out there.

[Sketchy_Racer]

Google ALPHA traction oil

http://www.chemcas.com/msds112/cas/2...3_128-37-0.asp
above is the MSDS

We use it in a Graham drive which is a common usage for it

Im sticking with the FXR route for now

Thanks for that.

If I knew it was all going to be this much work I probably would have never given it a shot, but I am to far in to give up now, gotta keep trucking!

[Sketchy_Racer]

Knowing very little about traction fluids, but 4.7kg force sounds like bugger all, I assume the force goes up if you have a bigger contact patch? Is the problem perhaps your contact patch is too small? Mind you, stands to reason if you were getting 5psi with far too large of a force, the correct force might bump it up enough. Be intersting to see how it goes with the better force anyway. Good perseverance btw!

Yes you are right, the force goes up with area, in my case my area is 0.05mm/2 and the oil is asking for a pressure of 92.5Kgf/mm2 and the area of my contact patch is 5% of 1.0mm2 so I need 5% of 92.5Kgf/mm2 which results to:

92.5 * 0.05 = 4.625

which is the force required on my contact area. I think, Im open to correction that I understand the force application correctly.

[Moooools]

Yes you are right, the force goes up with area, in my case my area is 0.05mm/2 and the oil is asking for a pressure of 92.5Kgf/mm2 and the area of my contact patch is 5% of 1.0mm2 so I need 5% of 92.5Kgf/mm2 which results to:

92.5 * 0.05 = 4.625

which is the force required on my contact area. I think, Im open to correction that I understand the force application correctly.

That does all look right. My question is how you obtained the 0.05mm^2 given you have two tangential surfaces. Is it just an approximation or are you taking the area where the two surfaces are within a certain distance of each other. i.e. doe the traction fluid take effect when 2 surfaces are 'x' close to each other?

[Sketchy_Racer]

That does all look right. My question is how you obtained the 0.05mm^2 given you have two tangential surfaces. Is it just an approximation or are you taking the area where the two surfaces are within a certain distance of each other. i.e. doe the traction fluid take effect when 2 surfaces are 'x' close to each other?

Thanks for the confirmation,

The contact patch is a semi calculated approximation drawn from the elastic modulus of the steel outer ring (annulus) and how much interference I will require to achieve the 92.5kgf/mm2 and at the given interference of 0.023mm on diameter (according to solidworks) I will see a interference area of 0.05mm2 which I have taken as a estimation of the contact patch on the rollers.

So really, it is just a guess but it is a figure to work with that I can measure from depending on the success or failure of the next attempt.

[jasonu]

Well, I wasn't going to post my failures, because it is rather embarrassing, but the supercharger still doesn't work.

I got the oil from Yowling and put it in with no modification of the charger and got LESS boost, was only getting 2psi and it was making 5 with CVT oil. I though to myself, surely I am not applying enough pressure to activate the phase change of the traction fluid to for the elasto-solid to transfer torque, so I made another outer ring (3rd time) with even more pre-tension and had to heat it to 150 degrees to get it on. I put it all together and ran the bike up, and managed 5psi which was a little more promising but after 2 minutes the oil inside boiled and blew all the sealer out and literally dropped it's guts. Luckily no damage to any of the supercharger parts.

So I left it for a day as I was pissed right off with it, but today I spent my lunch break researching traction fluids. I can't make out what brand exactly traction fluid I have (Yowling put MSI alpha traction fluid) but that returned no information on google. So I looked up all the alternatives and found that the major supplier of traction fluid is from Santolube from USA and their Santotrac 50 (http://www.santolubes.com/resources/...NTOTRAC-50.pdf) is the most common traction fluid that is usually re-branded. It was thoroughly tested by NASA when they were designing the mars rover gearbox along with many other traction fluids and surprisingly there is a LOT of information on the web about it. It turns out that the traction fluids are very sensitive to the loading they are put through achieve the dynamic phase change. Not enough pressure and it wont work, but also to much pressure and it will fail equally.

If you imagine that the fluid contains these long thin polymers that in most situations lubricate by preventing metal to metal contact (as most oils do) in a traction fluid when the right amount of pressure is exerted the polymers will align and grip each other and create traction (note: not friction) between the two surfaces, but if the pressure is to great the polymers are squeezed out and can't achieve this condtion.

So, in terms of pressure, all the fluids are the same sort of level within 5% and are asking for around 907Mpa (mega pascals) this equates to 92.5 Kgf/mm2 which when worked out to the contact patch of my outer ring on the rollers equals 4.628 Kg which is really not that much! Well, certainly a lot lot less than what I currently have.

I am going to the best of my ability try to achieve this loading upon my rollers. Upon dissasembly I have also learnt of machining tolerance failures so that the rollers were not contacting the shaft correctly so it seems that it may have been a combined effect of this failure.

So once again, no good news but I have learnt even more which is always fun, and still have enough oil for 2 more attempts so I hope I can manage it! I have emailed Santolube to try and source some oil also.

I will post in tomorrow to let you know how it all goes.

Sounds like some typical Bucket issues...

[Drew]

I bloody hate it when these threads get too clever for me!

All I'm reading now is that you won't ne able to help me with my bucket when I get round to finishing it.

[Sketchy_Racer]

I bloody hate it when these threads get too clever for me!

All I'm reading now is that you won't ne able to help me with my bucket when I get round to finishing it.

Haha, ignore the tech talk, basically the spinning thing doesn't spin because I'm a muppet and didn't build it right, today i'm going to try fix that

What are you doing with your bucket? it should be finished already, stop pissing around with that gay side car thing and get onto the real race bike.

[Drew]

Haha, ignore the tech talk, basically the spinning thing doesn't spin because I'm a muppet and didn't build it right, today i'm going to try fix that

What are you doing with your bucket? it should be finished already, stop pissing around with that gay side car thing and get onto the real race bike.

Oh right, that's my kinda language.

Bucket is on the back burner till we have our own garage. Sidecar is more fun to ride than a bucket...trust me on this. Come to the have a go day and have a ride on ours, you Will giggle so much you'll shit!

[Bert]

Haha, ignore the tech talk, basically the spinning thing doesn't spin because I'm a muppet and didn't build it right, today i'm going to try fix that

What are you doing with your bucket? it should be finished already, stop pissing around with that gay side car thing and get onto the real race bike.

Right I get it now.
Good luck with today's attempts; great work by the way. (knock sensor is on its way)....

Oh right, that's my kinda language.

Bucket is on the back burner till we have our own garage. Sidecar is more fun to ride than a bucket...trust me on this. Come to the have a go day and have a ride on ours, you Will giggle so much you'll shit!

Great days; we might have dig out stinky and come play too.

[Drew]

Great days; we might have dig out stinky and come play too.

Is stinky a proper Sidecar or a bucket?

[crazy man]

Is stinky a proper Sidecar or a bucket?

stinky is a play sidecar like yours a bucket one is a real one

[Sketchy_Racer]

Still nothing, It just doesn't want to work. I installed a oil pump to make sure that the oil supply was correct, it worked very well. I also measured that all rollers were getting even contact which they seemed to be (as best as I could test them) The outer ring seemed to have a reasonable amount of pre-tension on it, But here's the intersting part,

It makes 1 psi of boost at idle which sounds like it should make heaps once RPM comes up, but as soon and I mean as soon as the rpm rises the pressure drops and so does the flow to a point where it is really noticeable. So the only thing that can be happening is that the outer ring is expanding and creating slip.

Still got a couple more ideas, otherwise I am going to go down a different style but more on that later.

[Moooools]

Still nothing, It just doesn't want to work. I installed a oil pump to make sure that the oil supply was correct, it worked very well. I also measured that all rollers were getting even contact which they seemed to be (as best as I could test them) The outer ring seemed to have a reasonable amount of pre-tension on it, But here's the intersting part,

It makes 1 psi of boost at idle which sounds like it should make heaps once RPM comes up, but as soon and I mean as soon as the rpm rises the pressure drops and so does the flow to a point where it is really noticeable. So the only thing that can be happening is that the outer ring is expanding and creating slip.

Still got a couple more ideas, otherwise I am going to go down a different style but more on that later.

Huh. That confuses me. Originally I was going to suggest that the planetary gears were not getting even contact because they are in single shear. But the sun gear supports them so they shouldn't really get on the piss. I suppose they could be bending tangentially to the outer ring but you would see pretty clear wear marks. And you have checked for this so probably not that.

The ring heating up and expanding? What sort of temperature is it getting up to?

The bearings in the planetary gears outside their designed maximum velocities?

Only other thought is that your calculation for pressure is out for the sun gear. The planetaries are in single shear so probably have shiteloads of compliance compared to the strain on the outer ring. So they are probably deflecting inwards so that reaction force is present between the sun and planetaries that is close to equal to the force from the ring gear. The contact patch of your sun gear is going to be significantly less than your ring gear with pretty much the same force on it. Thus a much higher pressure and may not be in the correct range for the oil.

Other than that I have no clue what could be upsetting it. Sounds complex.

[Flettner]

Good on you, haven't heard one of those in ??? I don't know maybe thirty years or so.
I found that using a single was a problem, you need a large plenum ( intercooler ) but that give delayed throttle response. So I made a throttle valve at the cylinder head and a blow off valve in the plenum chamber, super charger was blowing all the time. Plenum chamber had an air to methanol inter cooler inside it, external radiator, I'm not sure how well it worked. My injection was a mechanical / electrical cross ( just like a dog too ).
Decided if I ever built another one, I would build a fourstroke tamdem twin, even induction pulses and some balance , and lots of revs!!!
That is soo ooo cool, thanks for sharing it.

Neil Hintz