Oddball engines and prototypes

[tjbw]

I was told Wankel engines were more suited to higher speed constant rpm operations,
how true is that opinion?

The competition success achieved by, Mazda, and Norton, doesn't support that view.

[eldog]

The competition success achieved by, Mazda, and Norton, doesn't support that view.

I know about the success, was just curious as a lecturer I had, a while back, mentioned about high speed running - maybe I wasn't listening properly at the time.
My memory isn't what it used to be. thanks for the info.

[husaberg]

I know about the success, was just curious as a lecturer I had mentioned about high speed running - maybe I wasn't listening properly at the time.
My memory isn't what it used to be. thanks for the info.

Maybe what he meant was they are better at constant sustained high rpm than the competition is.
Their balance is superior which help as does their lack of poppet valves.

or maybe he was refering to the competition carbon apex seals used until mazda devloped the ceramic seals..
these initial carbon apex seals were only effective at high rpm.

[WilDun]

Maybe what he meant was they are better at constant sustained high rpm than the competition is

A few years ago Norton were developing another Wankel suitable for aircraft, no doubt because of the smoothness and good power to weight ratio. In aircraft, constant speed running is the norm, however fuel consumption in aircraft is paramount and it looks like it may have fallen down there - can't see any other reason. Knowing that they had done a lot of development work with the Norton racers they should have had that sussed.
So why would they have tried it in that role without drastically improving fuel economy first, knowing that fuel consumption was so important?

I hope that if they (Wankel engines in general) can get the fuel consumption thing sorted and get HCCI working with it, that the Wankel will be back in business!
I'm not so sure that the Norton company (in the aero engine and industrial field) had much connection with the bikes - but I don't really know the story there though.

BTW I did notice that the racers did smoke quite a lot.

[Pursang]

I have a 'vintage-ish' cast iron 2-stroke cylinder, 64mm bore x 54 stroke, that is being developed to do something it was never intended to do.

The inlet and exhaust ports and ducts can be effectively enlarged by cutting, machining, s/s welding, brazing, etc.

The big problem is that it is severely transfer challenged. They are small, recessed into the cylinder wall, and fed only from windows in the piston skirt.

There is room in the wall for 12-15mm wide ports on either side of the existing one and heaps of empty space over the inlet.

So, the Oddball question, has anyone seen, heard of, or actually added, extra transfers to an engine, through EXTERNAL ducts? Google couldn't help much.

Nowhere at the cylinder to case junction to take them off, i will probably need to cut into the back wall of the main or tap them directly into the crankcase.

cheers, Daryl.

[Grumph]

Yes - early Kart engines were frequently modified like that. The McCulloch engines with barrel in unit with the case lent itself to welding in additional tubular transfers.
Personally, I've seen additional internal passages added. A Villiers Starmaker I rebuilt had been altered in Melbourne to have an additional pair of transfers via trenches in the bore - TD1C style. Made a significant improvement too.

[Pursang]

Thanks Grumph,

So not unheard of, and not without merit.

Engines in this family powered a lot of early Karts.

cheers, Daryl.

[Grumph]

Thanks Grumph,

So not unheard of, and not without merit.

Engines in this family powered a lot of early Karts.

cheers, Daryl.

Iron Horse ?

At least those dimensions give you a lot of modern alternative replacement parts.....

[husaberg]

A few years ago Norton were developing another Wankel suitable for aircraft, no doubt because of the smoothness and good power to weight ratio. In aircraft, constant speed running is the norm, however fuel consumption in aircraft is paramount and it looks like it may have fallen down there - can't see any other reason. Knowing that they had done a lot of development work with the Norton racers they should have had that sussed.
So why would they have tried it in that role without drastically improving fuel economy first, knowing that fuel consumption was so important?

I hope that if they (Wankel engines in general) can get the fuel consumption thing sorted and get HCCI working with it, that the Wankel will be back in business!
I'm not so sure that the Norton company (in the aero engine and industrial field) had much connection with the bikes - but I don't really know the story there though.

BTW I did notice that the racers did smoke quite a lot.

Pretty sure the Norton wankel aircraft project was for a pilotless target drone for missle testing the yanks used to modify mazada engines for the same thing. (racing beat i think)
So high fuel use wasn't really mission critical
Vincent engines were used for a similar thing (the picador)

The later Renesis as used in the RX8 partially solved the excessive fuel use by variable port timing and moving the EX ports to the side plates thus reducing overlap.
they also produced similar power to the earlier turbo models

[pete376403]

A few years ago Norton ...racers did smoke quite a lot.

IIRC the race motors used air cooling for the interior of the rotor. The air was pulled through using exhaust- similar to crankcase evacuation systems. The cooling worked but picked up oil which ended up as a smokey exhaust. One of the reasons the race motor could never have become a road motor.

[husaberg]

IIRC the race motors used air cooling for the interior of the rotor. The air was pulled through using exhaust- similar to crankcase evacuation systems. The cooling worked but picked up oil which ended up as a smokey exhaust. One of the reasons the race motor could never have become a road motor.

pretty sure they also used an oil feed total loss, only a small ammount though come to think of it i am pretty sure as the Suzuki RE5 was too. Highly likely the mazda was as well.
The britten used to smoke when cold, as did Dave Morris's BMW single.
the exhaust air vac pac, i think was later deleted when the cooling was improved on later models.
the race motor was develed directly from the road interpol which was very reliable.
I think all norton rotary's had the housings plated and machined by Mazda
the road bikes initally had the old triumph gearbox and i think later had a old Yamaha xj600 or similar gearbox.

[Pursang]

Iron Horse ?

At least those dimensions give you a lot of modern alternative replacement parts.....

It's a 'Victa' This cylinder is a 160 with 61.5mm bore std.

There is a Suzuki TS185 piston, at 64mm which gives 173.7 cc, perfect for the class.
If 64 is too big, the PE175 is available at 62mm.

Bottom ends are actually pretty solid. Unconfirmed reports of 16,000rpm in karts, way back when.
I won't be looking for any thing like that, 9,500 + some over-rev should be plenty.

cheers, Daryl.

[Frits Overmars]

I have a 'vintage-ish' cast iron 2-stroke cylinder, 64mm bore x 54 stroke... The big problem is that it is severely transfer challenged...
9,500 + some over-rev should be plenty.

Plenty indeed Daryl. Good cylinder filling at 9500 rpm would require a transfer angle.area of about 114000°mm². In other words: with a sensible 130° transfer timing you'd need over 100 mm total transfer port width. That will take some doing. And then you'll have swapped one problem for an other: how to cool that lump of cast-iron.
I wouldn't go there...

[Pursang]

Thanks for the input Frits. 130 degree of transfer was exactly my plan (& say 190 Ext & 166 inlet)

100mm of width should be doable. Efficient ducts to feed them will be the tricky part.

If I keep it piston ported, is there any reason I can't put a transfer port or two above the inlet port?

As I don't have direct access to the crankcase, except by tapping into the main transfer,
I am thinking of creating transfer 'holding chambers' outside the cylinder and feeding the extra ports from there.

Creating reasonable directions will be based on some good stuff I read somewhere about Pizza slices, or something.
Actually optimising and balancing the flow without a squillian hours of Sim & Dyno, is unlikely to occur.
I'll just try to make it look a bit like something that is known to work rather well.

Cooling the lump shouldn't be my biggest problem, Lots of airflow available.
I can even add water vapour to the air, if required and using Methanol fuel is another option.

20HP at the rear wheel will be ideal, with enough torque to steadily climb back from 38 & 27% rev drops in the lower gears.
I am also considering a CVT or go kart clutch between the engine & gearbox to help cope with this, despite the power cost.

I'm putting some pictures together, to post soon.

cheers, Daryl. PS Not many would go there, in fact None have....that why I'll do it!

[Pursang]

.
And...just to prove that an old mower engine is not a hijack of the rotary discussion.....







Discussion & more pics here: https://www.outdoorking.com/forum/ub...t&Number=42597

Cheers, Daryl.