Oddball engines and prototypes

[Pursang]

Those snowmobile turbos only blow into the crankcase and from there on everthing is conventional, with exhaust ports that close after the transfers, so the cylinders cannot be supercharged through the transfers.
The rotary drum in the Strange Development engine closes the exhaust ducts before the pistons close the transfer ports, so this engine can be supercharged.

I disagree. The turbo provides back pressure and the compressor raises the intake pressure. This runs the cycle as a whole at a higher pressure making more power. Some engines have gotten really serious with this and can make 800 hp with nitrous.

For Max Power, don't worry about charge loss to the exhaust, run full power rich and burn it off in the turbo, a bit like they did in the old 'Fuel Dump' FI & Rally cars.

Not applicable to the "Clean 2-Stoke".

Cheers, Daryl

[WilDun]

Looking forward to the Clean 2-Stroke Thread.

Cheers, Daryl

Daryl, I find light blue and yellow print difficult to read, - try using dark blue and red if you can!

[Pursang]

Will, You need to go to the Dark Side!, things are clearer here

Bottom Left of page!

Cheers, Daryl

[WilDun]

I've always been virtuous and caring person and have steered away from any "dark side" as much as possible! .....
I must say that I have never found the dark zone here to be particularly enlightening!

[Frits Overmars]

Daryl, I find light blue and yellow print difficult to read, - try using dark blue and red if you can!

Will, You need to go to the Dark Side!, things are clearer here

I've always been virtuous and caring person and have steered away from any "dark side" as much as possible! .....
I must say that I have never found the dark zone here to be particularly enlightering!

Daryl, I checked with various experts. The pastor, the vicar, the rebbe and the imam insist that I keep away from people who want to lure me to the dark side, and the ophthalmologist advised me to skip the hard to read texts. I had already thought of the latter myself, so goodbye Daryl

[WilDun]

Daryl, I checked with various experts. The pastor, the vicar, the rebbe and the imam insist that I keep away from people who want to lure me to the dark side, and the ophthalmologist advised me to skip the hard to read texts. I had already thought of the latter myself, so goodbye Daryl

Unfortunately, the two stroke has capitulated and gone over to the dark side, lured there by the bright lights of the chance of becoming the star in competition, but now it has died and gone to hell! - what are we going to do about it? ........ it will have to be reincarnated

Just to go back a little and a good example of where the two stroke engine might be used - A twin cylinder MZ which once powered the Trabant (East German car) was fitted in a small aircraft - I think I mentioned this somewhere before .......
In this role it would run at a pretty much constant efficient speed and with the prop being the transmission, it can cope with its role whilst remaining a simple engine, .................................................. ...................................

Here is the Trabant engine in action (along with a common or garden B&S V twin version of the same aircraft!).
The MZ does fit in a very neat package and sounds very nice I must say! - the Briggs neither sounds nor looks quite as good (but it can fly on only 22 BHP! would you believe)!
https://www.youtube.com/watch?v=ZKOrmETgMkM

[WilDun]

Who would have thought that Shrek would have been interested in a two stroke? ! - a great, light hearted look at the two stroke! - very good!

https://www.youtube.com/watch?v=vB0TK0Gdmh4

https://www.youtube.com/watch?v=nYCzbGaXShM

[lohring]

I grew up on model two stroke engines. I've written some articles on the history of model racing engines. See namba.com/content/library/propwash/2018/october/14/ for that history.

Lohring Miller

[Niels Abildgaard]

Cummins should "re-invent" the TS3 and TS4 Rootes engine that they killed off so long ago in favour of their own designs.

The Rootes concept was stillborn from start.
The piston pin bearing has always(and still is ) been problematic for normal speed two strokes.
This is due to always being loaded in one direction and not fully rotating.
In a fourstroke piston pin is reversed loaded when piston is in top between exhaust and inlet.
Some oil seeps in and saves the day during compression/combustion.
A normal two stroke cylinder has one of these problematic bearings,a Rootes type cylinder has eight.

[WilDun]

The Rootes concept was stillborn from start.
The piston pin bearing has always(and still is ) been problematic for normal speed two strokes.
This is due to always being loaded in one direction and not fully rotating.
In a fourstroke piston pin is reversed loaded when piston is in top between exhaust and inlet.
Some oil seeps in and saves the day during compression/combustion.
A normal two stroke cylinder has one of these problematic bearings,a Rootes type cylinder has eight.

Neils - I have identified the bearings you are discussing (after a few confusing moments) and you may be correct. However to say that Rootes/Sultzer engine concept was 'stillborn' is maybe a little harsh! - Stillborn means they didn't get off the starting block, but these engines did and were popular for many years!
They were far from stillborn, in fact they were actually very successful - Yes when they were called 'the knocker', what you are describing was no doubt the reason for the characteristic 'knock'.

I have to admit they were quite noisy, although strangely, not inside the cab!
I saw them being used (and abused) in heavy duty service by the local quarry for many years, also they have been around for probably sixty years in some fishing boats!).
These engines were very fuel efficient, compact and were practically vibration free,

I can testify to all the things I described, especially to their lack of vibration.

[pete376403]

Neils - I have identified the bearings you are discussing (after a few confusing moments) and you may be correct. However to say that Rootes/Sultzer engine concept was 'stillborn' is maybe a little harsh! - Stillborn means they didn't get off the starting block, but these engines did and were popular for many years!
They were far from stillborn, in fact they were actually very successful - Yes when they were called 'the knocker', what you are describing was no doubt the reason for the characteristic 'knock'.

I have to admit they were quite noisy, although strangely, not inside the cab!
I saw them being used (and abused) in heavy duty service by the local quarry for many years, also they have been around for probably sixty years in some fishing boats!).
These engines were very fuel efficient, compact and were practically vibration free,

I can testify to all the things I described, especially to their lack of vibration.

No real problem, getting oil to the small end bearing. All of the shafts (crankshaft, rocker shafts) would have been plain bearings, pressure fed, so a jet / drilling at the side of the rod could squirt up under the piston, to lube the small end and cool the underside of the piston crown.

they seem to be lasting ok here "Over 60 years later - in 2015, about 20 of these old commercial fishing boats still go fishing each day, powered by their original Rootes-Lister TS3 marine engines. "

http://www.commer.co.nz/history

An d with regard to noise - http://www.commer.co.nz/history/ts3-engine-history

[WilDun]

http://www.commer.co.nz/history

And with regard to noise - http://www.commer.co.nz/history/ts3-engine-history

Well that sure clears up a few misconceptions!!

[husaberg]

No real problem, getting oil to the small end bearing. All of the shafts (crankshaft, rocker shafts) would have been plain bearings, pressure fed, so a jet / drilling at the side of the rod could squirt up under the piston, to lube the small end and cool the underside of the piston crown.

they seem to be lasting ok here "Over 60 years later - in 2015, about 20 of these old commercial fishing boats still go fishing each day, powered by their original Rootes-Lister TS3 marine engines. "

http://www.commer.co.nz/history

An d with regard to noise - http://www.commer.co.nz/history/ts3-engine-history

Noise was never really the two strokes problem, they are very easy to quieten without losing performance, but its the frequency rather than outright Db that people assosicate with being noisey.
Whty is this the case People simply associate the higher frequencies as being more objectionable.

[WilDun]

Noise was never really the two strokes problem, they are very easy to quieten without losing performance, but its the frequency rather than outright Db that people assosicate with being noisey.
Why is this the case People simply associate the higher frequencies as being more objectionable.

Yeah but that's down to how it affects people and not everyone is the same - I normally like peace and quiet (also sometimes a two stroke in full song!) - some people would go mad with anything resembling either of those! - yet we're still all perfectly good people!

Big problem is, people tend to listen to other people and want to join in the sheep chorus - making things seem much worse than they actually are - this has been the tactics used by those looking for power from time immemorial! and even in our case, in the engine world, it is affecting the balance of power also (as it is intended to do).

A crowd without any individual thought and following an overpowering bullshit leader is rabble, who to my mind have no place in this world. - unfortunately that's not reality, (problem is, rabble often buys bikes too! ).

[jbiplane]

Any idea what engine is it and specs ~1940 production, used by German military.
Scavenging through piston