Never before has so little power been made from so much displacement! (Page 40 of 57)

I think we're seeing different things here.

What I think you're seeing: You assume (or maybe saw on an earlier photo I haven't seen) the chain was tensioned enough that, when stationary, it's tight between the sprockets on both sides. So, under load, the big wave on one side tells you the tight side must be stretching to create the slack that's evident on the slack side.

What I'm seeing: I assume that much slack was in the chain as assembled. That's a conventional thing for a motorcycle (though I think the reason is to allow for the slight change in sprocket-to-sprocket distance as the suspension moves through its stroke, so it seems unnecessary in this application). The big arc on the slack side is exactly what you'd expect to see with an o-ring sealed chain. The o-rings sealing each link cause a fair amount of resistance when you try to bend the chain. As a result, the chain, once wrapped around the sprocket, will tend to try and follow that curve as the individual links try to stay in their current orientation. This will cause the slack side to have a wave like you see in the pictures.

I have no idea which of us is seeing the truth (or if I'm even understanding what you're seeing)

-Dave

Ok Marc.  I think I read enough of this thread to be of some help.  I have played the chain drive car game a fair amount and figured out a thing or two.

First and foremost the main enemy of a chain is heat.  The heat is caused by the friction of the links pivoting as they round the sprockets.  A chain cools down on the straight sections between the sprockets.  If those sections are too short the chain will overheat.  Short chains die fast.  How short is short?  Under 100 links is a suicide mission unless it's in an oil bath.  That's the fact of it.  Speaking of lube, there are two things that are getting lubed on a chain:  The pins and the rollers.  The rollers are lubed from the outside with spray oil and this in not that critical.  The pins are pre lubed by grease that is contained by o-rings.  This is key.  What kills a chain is when the grease squirts out due to heat...

Next thing to talk about is tension.  There is really no such thing because properly shaped sprockets keep the chain rollers in the valleys of the sprocket and not the tension of the chain.  Vee belts rely on tension.  Chains don't.  All an over tight chain does is make more heat.  We run the chain on the Gnome with at least two inches of droop.

This brings us to sprockets.  The common thought is that they should be hard and stout.  Nope.  Really small sprockets (under 20 teeth) should be hardened steel but bigger sprockets work best out of aluminum because as the chain wears the alum beds in a bit and allows the load to spread over more teeth.  The key to the whole thing is to make the sprocket pull using as many teeth as possible.  Chain stretch is a misnomer btw.  It's pin wear.  As the chain pins wear the the links get longer.  If they get worn enough then they only engage the first few teeth on a sprocket.  Bad news.

Now for the really counter intuitive part.  You need to go to a smaller chain because your sprockets are too close together for a big one.  Go down in size until you get over 100 links.  If the smaller chain you are forced to use can't hold the torque then run them in duplex.  Or triplex.  Another thing you gain from a smaller chain is better cooling.  Something about volume going down on the square root with surface area or some shit. 

There are plenty of 530 chains that have working strengths over 10k lbs.  A quality chain like the EK ZZZ can handle the torque you have.  Think about a 150 Ft LBS motorcycle in first gear.  Prolly 500 lbs of torque on that coutershaft.  Decent quality 530 chain don't care.  Takes that abuse all day.  Moto chains are treated like crap by their users and still last an amazingly long time.  Clutch pops off the rev limiter and all that don't faze a good chain.  There is a huge range of chain quality out there though.  Any sport bike will have a good one.  Ebay will provide since sport bikes get crashed every 4th time they are ridden.  Sport bikes usually have chains in the 115 link range.

In closing, I can't exactly tell but it looks like you had a sprocket way out on an unsupported shaft.  Can't live long without a support bearing on the other end of the shaft.

I hope this helps you get closer to a design that can last a whole race.  I really don't think you need a cush drive or any of that.  The only reason some bikes have them is for comfort.  Just having sprockets on well supported shafts with a quality chain in the mix should be fine.

Not sure if I understand Marc.  Looks like a pretty long cantilever here.  The bearing is not the issue it's the flex of the shaft.  Am I missing something?  It looks to me that the shaft coming out of the engine would snap right off.

Also, your chain is not far from being workable.  A 530 chain would get you more links thus running cooler and it's same width as the 630 so it's load carrying abilities are nearly the same.  630 is a really arcane chain pitch from the pre o-ring days.

i know it looks bad on that top shaft. but the shaft is massive and strong. the scale might be throwing you off, the OD does not get any smaller than 4" at any point.

the sprocket is here: http://frankensteinmotorworks.com/Airpl … G_0243.jpg i'm liking instead of embedding it because it's a huge image.

Kevin Cameron in the current issue of Cycle World has a nice 1 page history of primary chains and lubrication.  It seems Matchless used open primary drive with 2 oil drips over the sprockets, which worked fine.  BSA experimented with a fully enclosed chain but they kept failing.  What they came to realize was that lubrication or not, the chains needed a lot of cooling air to keep from over heating.  So, if you do go to an oil bath, or an oil drip, make sure the chain is getting cooled some how along the way.

I looked but couldn't find it on their web site.  The source he was quoting from back in the day was saying a chain without enough oil eats up 2hp, which is the equivalent of 1500 watts of energy becoming heat.  The only thing that kept the chains alive was all the air moving over them.

http://www.youtube.com/watch?v=HHfOejlvVsY

did i mention that this thing hasn't run in 6 months and it's *STILL* leaking oil all over the damn shop?

these radials just leak. it's what they do.

*edit* don't you need a muffler to have muffler bearings?

I was just wondering the other day what happened to this project, glad to see it's getting back on track.

Hey, I was thinking about this the other day and I KNOW EXACTLY WHAT WENT WRONG!!!

Kidding... glad to see you are back at it. Look forward to more updates. Hope to see you and this car back at Gingerman next spring but this time we will be racing along with you guys.

I was gonna say I have a pile of zero balance 45# flywheels off large straight 6 truck engines.

But you just figgered that out.  Glad to hear youre still thinking about this.