#6

[Askor]

Awesome bit of work right there.

I have two questions:
-How much power do you think it will make when you've finished tuning it
-How are you going to reduce it to 100cc? Bore or stroke? (Assuming youre still going to run it in buckets)

[speedpro]

Awesome bit of work right there.

I have two questions:
-How much power do you think it will make when you've finished tuning it
-How are you going to reduce it to 100cc? Bore or stroke? (Assuming youre still going to run it in buckets)

No idea of power, probably not much. If it makes 20hp I'll be happy.
It's going to be magically destroked to make it 100cc

[speedpro]

In the ESE thread there was mention of a Hypocyclic mechanism. There are a few animations on the web I've found and one small motor running. It seems that there would be advantages, but then again, nobody seems to have built a useful engine using the principle. The way I see it you would use a plain bearing bottom end separated from the working cylinder allowing high reliable revving. Over that you could have a pretty much standard piston/port/cylinder arrangement, or you could go nuts with forced induction either direct or via the under-piston cavity(formerly the crankcase). As the rod to the piston only ever moves vertically there would be no piston side thrust which would reduce lubrication requirements due to lower or practically zero forces on the piston. The rings would still be in contact so I suppose some lubricant would be required. The ring lubrication might be able to be supplied by the fuel.

Does anyone have any links or any idea why it doesn't get used?

Animation here: https://www.youtube.com/watch?v=cvbFuw7mY74

[husaberg]

In the ESE thread there was mention of a Hypocyclic mechanism. There are a few animations on the web I've found and one small motor running. It seems that there would be advantages, but then again, nobody seems to have built a useful engine using the principle. The way I see it you would use a plain bearing bottom end separated from the working cylinder allowing high reliable revving. Over that you could have a pretty much standard piston/port/cylinder arrangement, or you could go nuts with forced induction either direct or via the under-piston cavity(formerly the crankcase). As the rod to the piston only ever moves vertically there would be no piston side thrust which would reduce lubrication requirements due to lower or practically zero forces on the piston. The rings would still be in contact so I suppose some lubricant would be required. The ring lubrication might be able to be supplied by the fuel.

Does anyone have any links or any idea why it doesn't get used?

Animation here: https://www.youtube.com/watch?v=cvbFuw7mY74

If you added a separate chamber outside of the engine you could control the size of the crankcase and also its primary compression. Likely with a bellows possibly augmented by ex pressure.

You could then also pick what ever delivery ratio actually suited the revs you were using at the time.
You will find also at high revs blowdown is not necessarily just measured in time or degrees, but in time or degrees above the transfer pressure.

Remember the biggest problem in the sixties was they had to keep shortening the transfer duration to stop the mixture flowing out the ex, we have exhaust valves now so this need not be much of an issue.
In the 60's also as the revs went up over peak the small area transfers could not flow enough. The other problem was as the crankcase was made smaller cooling and lubrication of the big end and flow into transfers suffered.
In case you are worried that the pipe might not be able to handle huge variations in revs I had a few minutes play today and came up with this.
Don't panic about the silly EX durations I used it was just a quick concept check. to see if the pipe could be made to work over a wide range just by ex duration manipulation.



This I think is how the Ryger works.
17000 i think is possible with a std crank plain bearings as the MX250s are doing 14000 is on conventional set ups with a 53mm stroke So if you can have the transfer high enough in pressure and have a large degree of control over a wide range of ex durations. I don't think it actually needs a funny bottom end.

Anyway the funny one looks pretty cool with its contra rotation and kind of reminds me of the wankels shaft and planetary.

[speedpro]

Been busy. Was talking to Kevin at Motorcad about my FZR and needing a brake-dyno and he goes "Have that one". That one turned out to be a steel frame,shaft, bearings, and a bunch of other minor stuff. John Connor donated the piece of round steel that has become the roller. We cut 2 steel discs which were welded into each end of the steel tube, and fitted a hefty piece of steel tube between into which has been fitted taperlocks to attach to the shaft. You see the end of the drum in one of the photos.
Initially I just want to run it up against the brake and sort out the Lambda. Not shown in the photos is a big flywheel that fits to the shaft that extends outside the frame. It'll help smooth out fluctuations. Kevin has a water brake as well but he doesn't seem keen on using it but it could be chain driven off the shaft in place of the flywheel. A bit later we are going to fit an eddy current brake and hook it al up to a computer to control it all. We're going to chuck the whole assembly in the lathe tomorrow to tru it all up. Checked it last thing tonight and the drum only runs out about .2-.3mm assembled onto the shaft so pretty happy with that. Got the essentially brand new 320mm disc out of the bin and Kev had the calliper just lying around. The brake torque arm is going to end up on a load cell to measure brake torque. The shaft will be mounted below the frame. It's just on top while we check a few things.
I love building stuff.

[Grumph]

Many years ago I was going to build a dyno using HQ disc and caliper. A local guy here had a rolling road for car setup which used two HQ disc/caliper setups with a hand controlled load cell. which wasn't really fast enough acting...However, he'd done the calcs and reckoned a single HQ caliper on the stock ventilated disc would easily handle 150HP without additional cooling. I had it about half built then got crook/broke/lost interest...
I've used both inertia and applied load dynos and if I ever did it again I'd go for the variable load type as IMO you can learn more from the ability to hold a load for a period.

[F5 Dave]

Golly, I don't know much about cars, (I did own one briefly in 1987 I think), but they don't care much about un-sprung mass do they?

[speedpro]

Slow progress on the dyno, just making brackets and clamps and stuff.

1st round today at Mt Wgtn. Dave slid off when he got caught out by old cold tyres being even slipperier than he thought, but no damage and just in a practice. Cricket also slid off Gary's MB in the prelim race. No damage except to his confidence. His 1st points race was a cautious affair but the 2nd he was back into it and managed a 5th or 6th I think. Dave scored 2 1st places riding like a demon but looking very smooth. Gary was flying as well but exercising a little caution, something about having to work for a living. Didn't catch the placing but up with the fast crowd. I'll mention him only because he parked his bike next to Team Shnanny - Blair, recently promoted from "B" grade was flying on his FXR and also was right in amongst the fast guys.

Only annoying thing was getting home and my son remembering to tell me the guy who had his van parked next to my car had a door bang the rear quarter. Cricket noticed it and the guy closed his door but didn't bother saying anything. Nice little ding in the rear fender. This car is like a magnet for this shit.

[TZ350]

Love that dyno, great to see the Team Shanny bike at the very pointy end.

[Henk]

Track was scary cold today, usual reasonably cautious out lap pace was giving me front end slides through the horseshoe both points races. Ok when the tyres warmed up a bit but still a few slides and nothing like fast times for the day.

[speedpro]

Love that dyno, great to see the Team Shanny bike at the very pointy end.

It's all Dave. That chassis is pretty good as well. Honestly the motor is not that flash at all though there's a good chance the Wobbly MB top end will end up on it shortly and that is special. Dave got it down to high 29s for a few laps.

[speedpro]

I'll just do a couple of dyno runs I thought to myself, just to check and maybe drop a jet size. 5th run and it went pop and went off. Every time I pulled the clutch in it stopped. Had a check of all the usual things but nothing obvious. Opened it up and something had been rattling round in the squish. Finally found this, damn.

[husaberg]

Mag side.

[speedpro]

Full rebuild later, crank, rod, all bearings, new piston & rings and it's running sweet. Except that it stopped twice with Gary riding it. Fired it up for the next race with Cricket on it and no problems. In fact he got a pretty convincing couple of 2nd places. Pretty sure I know what and where the problem is and it will need torque plates for the next hone to fix it. I noticed a slight tightening at the bottom of the piston travel as I was prepping to assemble the engine. It was OK with the piston rotated 90 degrees so the way we have been holding the cylinder for honing isn't working. We tried a size bigger main and pilot prior to Gary's 2nd ride but it still slowed up suddenly at the end of the straight.

[speedpro]

Bit of a change of topic now.

I've been thinking about internal combustion engines and how they might be compromised by their mechanical architecture, being they have a crankshaft with a rod connecting to the piston. The piston reciprocates as the crank rotates. With an infinitely long conrod the piston velocity will vary sinusoidaly as the crank rotates. As the rods are a bit shorter than that the piston velocity varies at a modified sinusoidal rate. Over time we have optimised the combustion as best we can to extract as much power from the combustion as possible given the mechanical constraints of the piston rate of velocity change as the crank rotates.

My question is - "If" an engine could be built that could have any piston velocity change at any point of crankshaft rotation, what rate of change in velocity would be the best to extract the most from the combustion, firstly if we retained the current combustion chamber profiles with the current burn rates etc? If, as I suspect, that combustion chamber profile is a compromise to achieve a burn rate that best works with the current crank/rod/piston compromise, what then would be the ideal combustion chamber profile to achieve the ideal extraction of power from the combustion process, if we weren't restricted to the piston velocity profile but could in fact make it anything we wanted? As now I see it being speed dependant.