rotary outboard anyone?

Searush said:
The video shows it running. Is that just a computer simulation then? Bloody good one if it is. :p
Click to expand...

As far as I can see, the video shows a 70cc version running. There is no sign that the 50cc one exists. Worth remembering that this is from Fox News, which is to miracle fossil fuel engines what the Daily Mail is to miracle cancer cures.

Update: actually, the video shows combustion, or claims to. Since the engine couldn't run if the combustion was visible, it's either a mockup or a CGI simulation. Their vimeo channel does have another video purporting to show an engine running for a bit, but I suspect it's actually running on compressed air.
 
Further update. This article is illuminating: http://www.gizmag.com/liquidpistol-rotary/24623/

First of all, they are claiming 75% thermal efficiency. This is spectacularly higher than any other IC engine and would require a working temperature inside of at least 1200K to achieve. In practice it would have to be considerably higher, since it ain't a Carnot cycle ... and yet they claim to need no cooling.

Their whizzy new cycle is shown as a standard theoretical otto cycle - adiabatic compression, heat in at constant volume (isochoric), adiabatic expansion, heat out at constant pressure (isobaric), except they claim to be able to get right into the corners of the p-v diagram by, for example, expanding almost down to atmospheric pressure. In which case, what drives the exhaust out? A highly tuned resonant exhaust might help, but that would make it extremely inflexible.

Finally they have been punting this idea for almost ten years, yet seem reluctant to tell anyone how the thing is actually supposed to work and don't seem to have any working examples for people to see.

My spidey senses are tingling, boys.
 
JumbleDuck said:
Further update. This article is illuminating: http://www.gizmag.com/liquidpistol-rotary/24623/

First of all, they are claiming 75% thermal efficiency. This is spectacularly higher than any other IC engine and would require a working temperature inside of at least 1200K to achieve. In practice it would have to be considerably higher, since it ain't a Carnot cycle ... and yet they claim to need no cooling.

Their whizzy new cycle is shown as a standard theoretical otto cycle - adiabatic compression, heat in at constant volume (isochoric), adiabatic expansion, heat out at constant pressure (isobaric), except they claim to be able to get right into the corners of the p-v diagram by, for example, expanding almost down to atmospheric pressure. In which case, what drives the exhaust out? A highly tuned resonant exhaust might help, but that would make it extremely inflexible.

Finally they have been punting this idea for almost ten years, yet seem reluctant to tell anyone how the thing is actually supposed to work and don't seem to have any working examples for people to see.

My spidey senses are tingling, boys.
Click to expand...



it does have the air of a bit of kite flying

however, it would have been awfully good in some sort of well contraption in a twin keeler of some sort
 
dylanwinter said:
it does have the air of a bit of kite flying
Click to expand...

My general rule of thumb is to distrust claims of multiple innovation in one device

Quieter or smoother or cooler or more efficient or more powerful or smaller or lighter? Maybe.

Quieter and smoother and cooler and more efficient and more powerful and smaller and lighter? Unlikely.

however, it would have been awfully good in some sort of well contraption in a twin keeler of some sort
Click to expand...

Well schmell. At their claimed size you could put one in a cute little yacht-sized azipod.
 
I wonder how many "miracle" engines (and indeed other "opportunities") there have been that have made some people a good living from research/development funding before disappearing?
 
gordmac said:
I wonder how many "miracle" engines (and indeed other "opportunities") there have been that have made some people a good living from research/development funding before disappearing?
Click to expand...

Loads, and as long as venture capitalists don't have engineering degrees they'll keep on coming.
 
Rotary engines. How long is it since Mazda brought out the Wankel engined car and how long did it last. Meanwhile a local guy (Sarich) here invented something similar which was going to change the world. A don't remember the details of the design it is so long ago. It went no where. So Inventors use the press release type hype to hopefully get investment in their idea which is inevitably optimistic to say the least. We seem to get on TV news once per week about some new break through usually medical which are never heard of again.
Meanwhile industry keep churning out reciprocating piston engines which are still apparently the best option for small outboard engines to large ship engines.
I doubt I will ever see any great change except to battey electric power. olewill

http://en.wikipedia.org/wiki/Ralph_Sarich
 
Last edited:
nimbusgb said:
3% in a decent single stage planetary box and 5:1 would be fine.

Gas turbines like the PT6 use a planetaery reduction box to get useable shaft speeds out.
Click to expand...

True but a PT6 also uses about 100 gph in some versions. Fantastic power to weight ratio until you include the fuel tank...
 
William_H said:
Rotary engines. How long is it since Mazda brought out the Wankel engined car and how long did it last. Meanwhile a local guy (Sarich) here invented something similar which was going to change the world. A don't remember the details of the design it is so long ago. It went no where. So Inventors use the press release type hype to hopefully get investment in their idea which is inevitably optimistic to say the least. We seem to get on TV news once per week about some new break through usually medical which are never heard of again.
Meanwhile industry keep churning out reciprocating piston engines which are still apparently the best option for small outboard engines to large ship engines.
I doubt I will ever see any great change except to battey electric power. olewill

http://en.wikipedia.org/wiki/Ralph_Sarich
Click to expand...
If I remember correctly NSU did the first production car with the Wankel, not a success. Citroen did one for a while too but Mazda did make a go of it for I think 20 years or so in sportscars, it's disadvantages aren't so critical in sportscars and it's advantages beneficial. Main problem is the combustion chamber has a high surface area giving heat loss rather than the heat providing power reducing efficiency, hence the poor fuel consumption.
I recall Orbital, on the face of it a good idea, a few manufacturers gave it a go but as I recall nobody could make it last.
 
You must log in or register to reply here.

Share this page

Top