Interesting engine?

Bill Daniels write:

"Jim Carriere writes:

.. From an engineering perspective, 0.25 lb/hp/hr is,
uh, extraordinary to say the least. Think of it like the internal
combustion engine's answer to cold fusion.

The gigiantic Sulzer marine diesels only get 0.278 lbs per hp per hour
on heavy bunker oil. That's about as good as it gets.
See: http://www.bath.ac.uk/~ccsshb/12cyl/

While I agree that the Bourke engine is vaporware, and doesn't/can't
achieve a BSFC of .25 lb/hp/hr, the web page you point to explicitly
states that the Sulzer diesel can achieve .26 lb/hp/hr.

Going from .26 to .25 is an advance of 4% - I hardly think that a BSFC
of 4% better than the best existing internal combustion engine puts it
into the category of cold fusion, or makes it violate the laws of
physics, as another poster implied.

Hyperbole isn't necessary here - no small internal combustion engine has
ever gotten near .25, and the Bourke engine certainly doesn't, but it IS
theoretically possible. Using ceramic materials instead of metals may
someday get us there.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2005

"Marc J. Zeitlin" wrote ...
Hyperbole isn't necessary here - no small internal combustion engine has
ever gotten near .25, and the Bourke engine certainly doesn't, but it IS
theoretically possible. Using ceramic materials instead of metals may
someday get us there.

Ceramic engines have been built but the material is far too brittle to make
a useful product.

Rich

Richard Isakson wrote:

Ceramic engines have been built but the material is far too
brittle to make a useful product.

Which is why I said "someday".

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2005

"Richard Isakson" wrote in message
om...
"Marc J. Zeitlin" wrote ...
Hyperbole isn't necessary here - no small internal combustion engine has
ever gotten near .25, and the Bourke engine certainly doesn't, but it IS
theoretically possible. Using ceramic materials instead of metals may
someday get us there.

Ceramic engines have been built but the material is far too brittle to
make
a useful product.

Rich

Hey! Some of the new engineering ceramics are ductile enough to pull into a
wire. Mark isn't talking crockery here. Ceramics are already used in
engines. Diesel exhaust valves in one instance, turbocharger hot sections
for another. If you make the piston crown, combustion chamber roof and
valves out of highly insulating ceramics, diesels can get a LOT lower SFC.
They're working on it.

Bill Daniels

Bill Daniels wrote:

Yup. The gigiantic Sulzer marine diesels only get 0.278 lbs per hp per hour
on heavy bunker oil. That's about as good as it gets. Of course that's
1660 GPH for 108,920 hp and 5,608,312 lb/ft of torque at 102 rpm for the
I-14. Oh yes, no PSRU, the propeller is direct drive.

See: http://www.bath.ac.uk/~ccsshb/12cyl/

Bill Daniels


OK So how large (gigantic) would a homebuilt plane have to be to use
this 14 cyl engine. And can I license it as an ultralight?
Very LARGE pun intended...
Rocky

"Richard Riley" wrote in message
OTOH, I'm doing some work now with a V6 that's getting an SFC of .05.
But that's on pure hydrogen, so the fuel system ends up a little
involved.

How big would the hydrogen tank be for a C-172?

D.

"rocky" wrote

OK So how large (gigantic) would a homebuilt plane have to be to use
this 14 cyl engine. And can I license it as an ultralight?
Very LARGE pun intended...

How about a single engine C-5A? Now, the trick is the prop size. We'll
have to use a PSIU (propeller speed increasing unit), but I still think we
are going to have to increase the length of the landing gear, or shaft drive
multiple props. g

And no, you will not be able to license it as an ultralight. BFG Shoot,
the engine to start the main engine will be heavier than most light planes!
--
Jim in NC

Marc wrote:
By coincidence, the energy in a gallon of liquid H2 is in the same
ball park as a gallon of gasoline, so figure a 50 gallon tank. But a
gallon of liquid H2 is just over 1/2 pound -1/12th the density of
gasoline. That - and the need to keep it at minus 423 degrees F-
makes for some interesting design tradeoffs. ;^)

Richard Riley! Is that you?

Jim in NC wrote:
And no, you will not be able to license it as an ultralight. BFG Shoot,
the engine to start the main engine will be heavier than most light planes!

I could salvage the metal in the crank shaft alone to pay off my
mortgages... "Damn that shaft's big!" saids wifey :)

"Jim Carriere" wrote in message
...
Ben Hallert wrote:
Howdy,

Just for comparison, the O-200 puts out 100hp at like 5-6gph of av gas,
right? Whether or not the engine mentioned can do it, it seems
difficult to believe that the O-200 is the height of efficiency. 100hp
at 4gph doesn't seem like that far of a stretch when compared to the
burn on the O-200, I guess, especially when energy denser fuels than
avgas exist.

That said, I don't understand what the bourke engine is supposed to do
different to get the numbers it describes, like another poster
mentioned, it looks like a two cylinder rotary.

Most internal combustion engines (including the O-200) have a BSFC
between 0.4 and 0.5 pounds/hp/hour.

I'd say an O-200 puts out 100hp at about 8gph, 5-6 gph is a typical
cruise fuel flow. 100hp is at sea level, wide open throttle, max rpm.
You don't spend too much flight time in that regime.

The O-200 is not the height of efficiency, but it isn't the height of
inefficiency either. From an engineering perspective, 0.25 lb/hp/hr is,
uh, extraordinary to say the least. Think of it like the internal
combustion engine's answer to cold fusion.

Also, consider which definition of energy density you're using. Avgas,
Jet-A, and kerosene have virtually the same mass energy density (avgas
is actually about one percent greater than Jet-A). A gallon of avgas is
lighter than a gallon of kerosene (and/or jet fuel, diesel), so it's
_volumetric_ energy density is less.

Actually, its energy density per pound should be the same, for "traditional"
gasoline; but less per gallon.

0.25 lb/hp/hr should be readily achievable for a stratified charge engine
which runs unthrottled at a modest power output. That is how the diesels
accomplish it.

As to that kind of efficiency, and a reasonable weight, at a power level
that can fly an aircraft; medium size and larger turboprops are still "the
only game in town" and that won't change anytime soon!

BTW, I too regard this engine as impractical and vaporware, it addition to
the efficiency being unlikely.