The "Three-Cylinder" Commando

For those who recently expressed an interest in the factory prototype I have and ride occasionally, see http://www.andover-norton.co.uk/Jake.htm.
Joe Seifert

Thats one way to reduce norton vibration. But its a hell of a lot more trouble than just installing lightweight pistons & longer rods.

Thanks for posting 8)

That's what I thought it would be, but I was hoping to see a third "combustion" chamber, Norton T160 type thing.

jseng1 said:

Thats one way to reduce norton vibration. But its a hell of a lot more trouble than just installing lightweight pistons & longer rods.

Click to expand...

Yeah, but back then the materials then wouldn't have supported a lightweight piston.

It's fascinating to see evidence that NVT at least tried to further improve the breed. I can't help thinking that a water-cooled in-line four, like the BMW layout, would have been a lot less bother. It would have been ahead of the BMW, 4-cylinfder bike, if I recall dates correctly. Double up the 500 cc Dominator engine with a proper 4-cylinder car-type crank. When I was at N-V I really wanted the company to do a 4-cyliner 1-liter shaft-drive touring bike, based on the Commando, but the development money wasn't there and not too many of the "gurus" though it was a good idea. They were still in the "inexpensive performance bikes for people who can't afford a decent car" mode. The idea of motorcyles as a hobby vehicle, rather than a cheap commuter rig hadn't penetrated.

This concept looks like an attempt to make a silk purse out of a sow's ear, an example of development trying to solve a fundamental design flaw.

Congrtulations on trying to keep that bit of history alive.

ditto--thanks for the post. Cj

For Fundamental Design Flaw , read Fundamental Design Characteristic .

seeing there was already the Hanson / Mundy 850 / 1000 four , there wouldnd be a lot of point designing another one ?
There the Chaps that did the Coventry climax , Hillman Imp , and Jaguar V-12 . The middle one ruined by a poor installation .

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

Intresting to know the forums for sows ears entusiasts , frank .Heaven knows what the Jappers were ,
incapable of beating the Archaic poms , in the i.o.m. , untill the industry collapsed .

Most people recognised the i.o.m. as the closest related to road machines of the entire gendre .

Seeing Dewcati were able to obtain another fifteen hundred rpms from their 500 supermono useing
a near identical concept ( false piston - tangental rod ) and BMW have adopted a derivitive off it in
their ' sows ear ' currently , the ' Obsolete ' parralell twin , one wonders on the merits of the comments
to say the least.

Notably Aston & Jag would use a ' five bearing ' Hare to break the mercedes hounds at Le Mans ,
recogniseing its greater stressing would result in failure . Noteably though , it was more powerfull
as less bearing drag absorbed the horsepower .

A roller bearing bottom end ( mains ) in the Norton & Triumph further enhanced the output .
Why , one even set the World Speed Record , at 240 mph odd .
Sows Ear Indeed . Sounds like a K1 750 Honda .

jseng1 said:

Thats one way to reduce norton vibration. But its a hell of a lot more trouble than just installing lightweight pistons & longer rods.

Click to expand...

Done right it's also a hell of a lot more effective than only installing lightweight pistons and longer rods.


Tim

Thx for this, interesting.
P for primary, S for secondary?
Apparently some design changes when sketch evolved into actual crankshaft in picture:
-shorter "stroke" for the balancer rods in the sketch not retained on the actual crank built
-from 2 rods to one. Maybe they went to 1 rod because no room at the back of the crankcase. Wonder why 2 rods initially anyway?

Probably just a first sketch, and after the practical tests Doug Hele may have ended up where Ducati did, only decades later. The idea was not pursued, the Cosworth used counterrotating shafts, then the taste of the season.
The bike has hairline steering and the first time I showed it to my eldest daughter's ex-boyfriend, who is on an engineering course, the first thing he noticed was the front wheel did not go to and fro at tickover, as it does on all "normal" Commandos. He then rode the bike and was enthusiastic about its smoothness- he owns a 750 Commando.
He had just had a lecture by a BMW director on the groundbreaking anti-vibe work they did on the F800, and I asked him to take a photo and show it to his lecturer, not forgetting to say this bike was nearly three decades old.
Joe Seifert

Didn't DKW do a supercharged 2 stroke, with the 'compressor' piston laid down in front like that. 80+ years ago now.

Nothing is ever new..

P.S. Said to be the only bike to race in the island (IoM) that could be heard on the mainland - 80 miles away. Wind must have been right....

ZFD said:

He had just had a lecture by a BMW director on the groundbreaking anti-vibe work they did on the F800, ...

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BMW just introduced that design when a VW patent covering exactly this system ran out. AFAIK they don't own any patent which covers the system itself, just the usual b*llsh*t to pretend they actually do. Same story with their Telelever which Saxon did initially and the Hossack FFE they call a Duolever - introduced exactly 25 years after Norman Hossack filed his first patents. I'm not aware of any innovation on a BMW motorcycle with which BMW came up in the first place.... :twisted:



Tim

An interesting story. Thanks

Tintin said:

ZFD said:

He had just had a lecture by a BMW director on the groundbreaking anti-vibe work they did on the F800, ...

Click to expand...

BMW just introduced that design when a VW patent covering exactly this system ran out. AFAIK they don't own any patent which covers the system itself, just the usual b*llsh*t to pretend they actually do. Same story with their Telelever which Saxon did initially and the Hossack FFE they call a Duolever - introduced exactly 25 years after Norman Hossack filed his first patents. I'm not aware of any innovation on a BMW motorcycle with which BMW came up in the first place.... :twisted:



Tim

Click to expand...

They innovated this piece of shit.

Which sold like hotcakes. For $$$
Must be a lesson in there somewhere ??

Same market the new Norton is after ?

Brains arnt compulsary ?
One of those P.o.S. in town here , uses it as Vespa .

DKW I think had Compressor Cyl aft and parrallel to main Cyl ,
so cross fed under head , phaseing closes cross passage about
the top of the stroke .

DKW had a layout exactly like Commando here.

The front 'cylinder' provided both supercharging and balance duties...

Rohan mistakes the "singing saw" three-cylinder racing DKW for one of their "Ladepumpe" (compressor) models. The "singing saw" had three conventionally aspirated cylinders, with the front one at significantly less than 90 degrees to the upright ones because the upright ones were tilted forward. So the layout, whilst similar, was different in function and in geometry and could not have the same result as the "three cylinder Commando" engine vibrationwise.
The "Ladepumpe" models had the "compressor" piston diametrically opposed to the "working" piston.

Joe Seifert

Rohan doesn't mistake anything.

"These monsters had three cylinders, one mounted horizontally on the front of the crankcase acting as a compressor, but doing no combustion. There are two more vertically mounted, finned cylinders in the 'cylinder block etc etc"

And I've seen (and HEARD) it race. Even with a form of silencing and without the original style megaphones, and a lower rpm limit, it emitted a noise that was beyond an ear splitting SHRIEK...

If you read around, the supercharger cylinder also did the balancing, EXACTLY like the Norton is set up.