the clean two-stroke thread

[husaberg]

How about this Neil?
Only one crankshaft, so no need for a gear train to join two of 'm.
It's a boxer, so no need for a balance shaft.
It will be easy to separate the crankcase from the volumes 'under' the pistons.
You can have your shaft drive without the need for a bevel drive at the gearbox.
It will be a lot narrower than a BMW. In fact you could drop it right into a BMW frame for testing. And with the cultivated behavior of a TPI two-stroke it would make a great touring bike.
Attachment 347039Attachment 347040

TS3 Horizontally Opposed Piston Engine
Rootes Motor Group built an engine for their trucks which was a design loosely based around an original Sulzer Brothers concept,



but why stop there.

[Flettner]

I've seen them.
In fact my last 100cc supercharger was a TS3 supercharger cut down to the right width for the required volume.

[Pursang]

Nice Idea, Perhaps it was appropriated by Rootes as Spoils of War.
ala DKW-BSA Bantam

[WilDun]

No, Sulzer is a Swiss company, not German - and I believe they are still in business......... Switzerland didn't take part in the war - well, they held the coats while the others fought.

I also remember the TS3 Commer trucks at the local quarry - the drivers used to remove the engine governor - they went like hell!
They were also very smooth running engines (had a trip in one) - very successful engines, but noisy! (although not really noisy inside the cab).
- Still used in some fishing boats till this day!!

The Napier "Deltic" - (second picture) was also very successful as a locomotive engine with British Rail for many years. (think it was 12 cylinder) - it was inspired by the Junkers Jumo (boat engine) which was built under licence by Napier before WW2.

[Pursang]

Hi Bill,
The sectioned engine in Frits' picture is an Auto Union - DKW from 1938.

That's about 10 years & one World War before the Commer.

If the Blueprints for the DKW RT125 made their way back to GB, I bet lots of other stuff did too.

A well know US Automobile manufacturer also had a patent on a Lightweight OP 2stroke diesel back in 1934.
(Shortly after buying a firm with a licensing agreement with the Sulzers).

Totalitarian regimes, with an eye on world domination, are rarely concerned about Intellectual Property laws.

I really like the big tie rod through the rocker pivots holding it all together.
Only needs very light, non-structural outer covers or castings.



Cheers, Daryl

[WilDun]

Hi Bill,
The sectioned engine in Frits' picture is an Auto Union - DKW from 1938.

That's about 10 years & one World War before the Commer.

If the Blueprints for the DKW RT125 made their way back to GB, I bet lots of other stuff did too.

A well know US Automobile manufacturer also had a patent on a Lightweight OP 2stroke diesel back in 1934.
(Shortly after buying a firm with a licensing agreement with the Sulzers).

I was looking to post that one but couldn't find it - From memory, I believe that picture was from the guy (Olds) who started Oldsmobile! - good picture (notice the out of phase cranks?).

[Flettner]

How about this Neil?
Only one crankshaft, so no need for a gear train to join two of 'm.
It's a boxer, so no need for a balance shaft.
It will be easy to separate the crankcase from the volumes 'under' the pistons.
You can have your shaft drive without the need for a bevel drive at the gearbox.
It will be a lot narrower than a BMW. In fact you could drop it right into a BMW frame for testing. And with the cultivated behavior of a TPI two-stroke it would make a great touring bike.
Attachment 347039Attachment 347040

I'm combining these https://youtu.be/BPr694nlUKE

https://youtu.be/TOHKls3Cxjs

https://youtu.be/cuSnfRgyEZk

[WilDun]

In the present project, or later?

[Flettner]

No not this one, next perhaps.
This one already had some new stuff to test, one step at a time

[Norman]

Ceci
No, I would just find her a job and send her off to work instead ....... and I would stay at home, tidying up the house etc. (takes the best part of an hour) then spend the rest of my day designing and building the perfect two stroke! - might even employ a housekeeper! .......... then maybe not - my age might not allow me to do that! - oh well!

Norman
Thanks for that article - that was written just when I was starting to take an interest in motorcycles again after over 25 years off, so I hadn't read much about developments around then.
I found it very interesting indeed and agreed entirely with most of what he was saying , but I had always looked on a two stroke as a competition machine with Schneurle scavenging (as this guy obviously did.) ...... I think Uniflow now!

Since my life had changed dramatically through severe health problems, I could no longer ride bikes (to do so and risk falling off would have been the end for me!) - then I found computers and forums! and have never stopped talking since!

I am still learning and just as keen as I was over 50 years ago, but my ideas have changed and I am more concerned with the fate of the more mundane two stroke and how to make it as clean as these exotic competition machines, but still keep it inexpensive! ..... ie in the future when it might actually need to be the breadwinner (through huge sales in the commuter market etc).

Maybe Ceci is right about ditching electronics I dunno - but why? when it works fine and is actually well developed and relatively cheap!

Anyway thanks for sharing

Inspiring to hear that you highly enjoy the two stroke world in spite of your health issues Wildun.
One of my school friends father was a two stroke engine designer at Volvo Penta, a very clever man. In their home workshop, with a lot of proto two stroke engines laying around, I more than once got help to fix my expansion chamber needing welding reapair.. But more important, I also got tips to improve the performance of my Suzuki GP125 to be able to keep up with my friends RD125LC:s. Very fun times, the days everything worked as it should that is..! Somewhere there it all went "wrong" and the addiction is there, and I have accepted that it will never go away .

[Flettner]

The twostroke virus, yes,

[husaberg]

The twostroke virus, yes,

I have always been intrigued why you were so keen on the Uniflow Neil that one simple animation of the Commer answered it.

[husaberg]

Hi Bill,
The sectioned engine in Frits' picture is an Auto Union - DKW from 1938.

That's about 10 years & one World War before the Commer.

If the Blueprints for the DKW RT125 made their way back to GB, I bet lots of other stuff did too.

A well know US Automobile manufacturer also had a patent on a Lightweight OP 2stroke diesel back in 1934.
(Shortly after buying a firm with a licensing agreement with the Sulzers).

Totalitarian regimes, with an eye on world domination, are rarely concerned about Intellectual Property laws.

I really like the big tie rod through the rocker pivots holding it all together.
Only needs very light, non-structural outer covers or castings.



Cheers, Daryl

Hi Dazza the Simpson as posted by you was 1914

[WilDun]

We need to note that the big picture above is not a DKW - possibly Sulzer inspired of course.

There is (to my mind anyway) something wrong in the picture ..... Assuming that crankshaft rotation is clockwise of course, the cranks are clearly not at 180 deg to each other, so the crank controlling the right hand piston has not yet reached the TDC position - so why are both rockers positioned exactly the same - ie at the end of their travel??

This is of course is an OP engine, but it's also a Diesel and Diesels don't figure in the 'clean two stroke' picture these days!

(But I may have got it all wrong!)

Inspiring to hear that you highly enjoy the two stroke world in spite of your health issues Wildun.
One of my school friends father was a two stroke engine designer at Volvo Penta, a very clever man. In their home workshop, with a lot of proto two stroke engines laying around, I more than once got help to fix my expansion chamber needing welding reapair.. .................. Somewhere there it all went "wrong" and the addiction is there, and I have accepted that it will never go away .

NORMAN
My health 'problems' aren't really a problem these days (actually have not been for around 10 years - except for one 'flare up') - and it was during the time I was recovering that I found this forum and enjoyed following Flettner's enthusiasm for building his own engines (including his own castings).
I managed to build a small foundry for myself, but having had to downsize my home, I found that it was not the place to have a foundry!


(My addiction to the two stroke has lasted for more than 60 years) - since the days when I first saw Ernst Degner, Horst Fugner and Werner Krumpholz riding MZ's at the Ulster GP! (I must admit my initial interest came via model aircraft engines from the age of fourteen).

However, I had to learn for myself - I didn't share your luck (ie having someone around who understood the two stroke). - the main topic where I lived was, how many cows they owned, the price pigs and cows were fetching at the market, who had the biggest tractor, or moaning about how much tax they paid last year etc. etc.
Not a lot of scope for a budding two stroke engineer! - so I emigrated to New Zealand 54 years ago! ..... but found that they were exactly the same! - however, I decided to stay anyway! - and happy to have done that! - now a New Zealander!

[Pursang]

Hi Dazza the Simpson as posted by you was 1914

Thank-you for pointing that out (so, that's 2 World Wars before Commer), I've swapped the pic!.

There is (to my mind anyway) something wrong in the picture ..... Assuming that crankshaft rotation is clockwise of course, the cranks are clearly not at 180 deg to each other, so the crank controlling the right hand piston has not yet reached the TDC position - so why are both rockers positioned exactly the same - ie at the end of their travel??

This is of course is an OP engine, but it's also a Diesel and Diesels don't figure in the 'clean two stroke' picture these days! (But I may have got it all wrong!)

I think the Patent drawings were more conceptual, rather than actual blue prints. Plus, it's a great way to keep 'Reverse Engineers' on their toes, even 90 years later!

Reference to the patent description explains, thusly: https://patents.google.com/patent/US2099371A/en

The throws are so arranged that the opposed pistons in both cylinders move in the same direction, but the throws 28 and 29 controlling the movement of the pistons 19 in the cylinders are disposed approximately 15 degrees back of the throws 27 and 30 so as to effect a phase difference of approximately 15 degrees between the motions of the pistons 19 and 20. In other words, the throws of the crank for operating the pistons controlling the exhaust ports are disposed in advance of the throws for operating the pistons controlling the intake ports, so that the exhaust ports will not only be opened before the intake ports for scavenging purposes, but will also be closed before the latter ports for supercharging purposes. (Thus satisfying Physics & Frits!)

The numbers in the description might be screwy, probably from optical character recognition, when the patent was digitised)

I'm sure one could argue that Diesel & HCCI are just different types of compression ignition engines.

Here is a pic from end on.