V8 fuel flow

"stol" wrote in message oups.com...
Lean mixture makes the exhaust hotter, not a rich mixture.


Up to a point, then it gets cooler...

stol wrote:

My Zenith 801 is running a 347 cu in all aluminum Ford V-8. I detuned
it to about 310 hp to keep the plane from breaking in half and on
take
off I am burning 11.8-12.3 an hour.

Ben,

This equates to a BSFC of about 0.22 , essentially "impossible".



Remember, on aircooled motors they use 30-40 % of
the fuel just to cool the heads/cylinders.

Please explain the reasoning behind this (IMHO bizarre ) statement.


Sid Knox
Oklahoma
Velocity N199RS
Starduster N666SK
KR2 N24TC
W7QJQ

On 20 Jan 2005 21:57:24 -0800, wrote:

stol wrote:

My Zenith 801 is running a 347 cu in all aluminum Ford V-8. I detuned
it to about 310 hp to keep the plane from breaking in half and on
take
off I am burning 11.8-12.3 an hour.

Ben,

This equates to a BSFC of about 0.22 , essentially "impossible".

Sid, you must have missed the following, it explains a lot:

"Let me clear up some things. My plane is tied down in its hangar at
almost 7000 feet msl. So the 310 hp is down 22% right off the bat, now
it's at 240 or so. The fuel flow for that HP range is damn close. I
agree that any motor running below .38-.40 is pushing the limit on
thermal dynamics of current technology. I admit that there is some
cutting edge stuff in my motor that helps squeeze out more hp per pound of fuel.
Ben Haas N801BH Jackson Hole Wyoming"

Ben wrote:
Remember, on aircooled motors they use 30-40 % of
the fuel just to cool the heads/cylinders.

Sid asks:
Please explain the reasoning behind this (IMHO bizarre ) statement.

When properly set up aircooled engines with fixed timing (which
describes all of them except for those equipped with electronic
aftermarket timing or FADEC) are advanced to full power, the fuel
system is designed to produce a strongly overrich mixture in order to
prevent detonation and overheating.

There may be some confusion as to how an overrich mixture actually
achieves this. The answer in depth may be found at:
http://www.avweb.com/news/columns/182084-1.html

REALLY simplifying the explanation, since the timing is fixed, the
only way to vary the timing is by varying the mixture. The speed of
combustion within the combustion chamber will vary from very lean to
ideal to very rich: going from slow (relatively speaking) to fast and
back to slow again respectively.

Engineers preset the point of ignition in order for the peak pressure
point to occur at 16 degrees after top dead center while at full power
and full rich mixture. This is the point where the combustion reached
it's maximum pressure during the combustion process. Engineers have
long known that the PPP should occur at 16 degrees ATDC for maximum
power and cooling.

If the mixture is leaned while under full power the combustion will
speed up. If the combustion speeds up, the PPP may begin to occur at
close to TDC. If the PPP is occurring at TDC, all that pressure has
no where to go and pressure and temperatures skyrocket.

This is why you do NOT lean the mixture while the at full power and
taking off, unless you are at a high altitude airport, which is
another story. It's also why you should NOT pull back the throttle in
an effort to "save" the engine. Pulling back the throttle slows the
engine (fixed prop), which brings the PPP close to TDC (bad).

Anyway, the rich mixture for takeoff allows the engine to achieve it's
best PPP location at 16 degrees ATDC which allows the engine to
produce maximum power and not overheat. It does not cool the engine
by hosing down the combustion chamber with excess fuel.

Corky Scott

Please read the followup post I did for an explaination. You seem to
have pasted the SEA level output I quoted, not the real enviorment it
is flying . I am SURE the fuel consumption will be a lot higher DOWN
there.So Lets see, 12.6 X X 6 is 73 pounds per hour divided by 240 hp
gaves a number in the low three range. The main reason I am seeing 12.2
or so GPM is because I don't use FULL power. The whole idea is to have
plenty of EXTRA HP and use just what one needs for the task at hand.
Maybe one day when I get real crazy I will throttle it up some more, if
the plane don't break in half.. After all I only have two feet to push
on the right rudder. After 60+ hours on this package it has
demonstrated everything I was expecting and more. The motor is WAY
smoother then a Lyc or Cont, starts on the first couple of turns
everytime and can burn either 100LL or car gas. I do commend you on
taking the WRONG numbers to make your calcs with. IMHO you are bizarre
in your approach. But what the hell, this is a free country, better
yet. Come on out and strap yourself in and see for yourself, is ya
promise not to throw up in my plane.. Bring Barnyard Blob anong too..I
am betting all three of the planes you list below your name has a
aircooled engine in them,

Ben Haas

stol wrote...

After 60+ hours on this package it has
demonstrated everything I was expecting and more.

I don't doubt that someday someone will build
a successful auto conversion. Maybe someone
already has. Maybe it's you. But you sure
as snot don't know for sure after only "60+ hours"
unless that plus adds a zero or two to that 60.

Dave 'accelerated service test' Hyde

On Fri, 21 Jan 2005 15:21:19 GMT, "Dave Hyde" wrote:

I don't doubt that someday someone will build
a successful auto conversion. Maybe someone
already has. Maybe it's you. But you sure
as snot don't know for sure after only "60+ hours"
unless that plus adds a zero or two to that 60.

Does 2,000+ hours count? There is a Ford V6 STOL that achieved that
mark several years ago. The owner/builder reached that time and tore
the engine and PSRU down for inspection. He found no discernable wear
in the cylinders and the belt appeared still viable. My understanding
is that he installed new bearings and replaced the psru's cog belt
anyway.

Bruce can likely give more detailed information.

Bruce can also give numbers on how many of the Ford conversions are
over 1,000 hours.

Corky Scott

PS, I did not see where Ben claimed anything other than that he built
the conversion and it is working fine so far.

Years ago when I lived in PA I watched as a FWF 0-320 was pulled off a
plane at the FBO (can't remember what plane). Just for the information the
mechanic weighed the package, wet without the metal prop. The weight came
to 420 lbs which was only 20 pounds less than the FWF Ford V-6 installed in
the mechanics plane.

stol wrote:

Morgans wrote:
"Blueskies" wrote

That is an in-flight adjustable prop, not constant speed but still
adjustable. I think the writer is saying the weight
compares favorably with a IO-360 with all accessories and a
constant speed
prop. The only real operational issue is the
requirement to watch the prop pitch control vs. manifold pressure
and
twiddle as necessary to set the power; not quite
as easy as a constant speed but configurable never-the-less...


Right. I think other people's hesitations about the poster saying
the V-8
is lighter, is possibly justified. Nevertheless, the possible
heavier
weight should be more than offset by the higher HP, and I commend
someone
giving alternate power a real, (from how it appears) well thought out
application, a chance to work.

As far as claims of fantastic economy goes, I think that anyone
claiming to
be getting *substantially* better than .38 lbs/hp/hr, even with a
modern
liquid cooled engine, are suspect.


Good luck to the OP. I wish I were involved in the project. Test
test
test, before flying!
--
Jim in NC

Let me clear up some things. My plane is tied down in its hangar at
almost 7000 feet msl. So the 310 hp is down 22% right off the bat, now
it's at 240 or so. The fuel flow for that HP range is damn close. I
agree that any motor running below .38-.40 is pushing the limit on
thermal dynamics of current technology. I admit that there is some
cutting edge stuff in my motor that helps squeeze out more hp per pound
of fuel. For instance my egt is running 1600 + on takeoff but this also
has an explanation. my probe is in the collector, not the head pipe so
the the egt number looks high for sure. Took me a while to find some
trick collector gaskets that can stand that kind of temp. An aircooled
motor in the low .40 range is kinda hard to believe. Now if they add
some ceramic goodies to their product they might get close. Lyc and
Cont are realizing they are so far behind the tech curve that stating
the FADEC is the future of their aircooled powerplants is like buying a
bridge somewhere. Truth is Horsepower=Heat. The better one converts
that to motion is ahead of the pack. I believe Dave Hyde asked the
question ,How did a 0-360 gain so much weight.Well, lets add things up.
0-360 "Bare" and dry is 293,, Maybe,, add starter,Flywheel, ringgear,
alt, fuel system and pump, fuel lines, shrouds, mags, wiring harness,
brackets, exhaust system, mufflers, heat muffs, Scat tubes, clamps,
oil filter, oil, oil cooler,oil lines,engine mount, cowling, prop,
governor, bolts, nuts, Etc !!!!! I have weighed a Lyc all dressed out
and it is alot heavier then most people think. Only in America can one
create a better flying mouse trap....God Bless the USA !!!!!!!
Ben Haas N801BH Jackson Hole Wyoming

--
Bruce A. Frank, Editor "Ford 3.8/4.2L Engine and V-6 STOL
Homebuilt Aircraft Newsletter"
| Publishing interesting material|
| on all aspects of alternative |
| engines and homebuilt aircraft.|
*------------------------------**----*
\(-o-)/ AIRCRAFT PROJECTS CO.
\___/ Manufacturing parts & pieces
/ \ for homebuilt aircraft,
0 0 TIG welding

While trying to find the time to finish mine.

Geez. Once again I screwed up and posted my results from my auto
conversion on the wrong web group. You see I was trying to inform all
the EXPERIMENTAL people that are " dreaming, thinking about, building
or just curious about homebuilt aircraft and dumb me I posted it on the
CERTIFIED plane group instead I put it here.........


Wait !!!!!


late breaking news !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


This is the rec.aviation. HOMEBUILT. newsgroup. Please Dave Hyde find
something wrong with this ...

Ben' thank god I don't have a certfied Lycoming crank that will break
in my plane' Haas.

Very well explained Corky !!!!!!!!!!!!

Blueskies

Are you saying that if you lean the mixture until engine quits, then
the EGT goes down?

I'm still alive but lurking )

Big John
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~````

On Wed, 19 Jan 2005 23:09:06 GMT, "Blueskies"
wrote:


"stol" wrote in message oups.com...
Lean mixture makes the exhaust hotter, not a rich mixture.


Up to a point, then it gets cooler...