VW Reality

[[email protected]]

> *******************************************
> "...the great little VW
> conversion with a 2.0:1 reduction producing 103 HP."
> ---------------------------------------------------------

To All:

In the context of an engine converted for flight the figures above are
wildly fallacious. At best, they represent a 'dyno blip,' at worst
they may be an out-right lie. Here's why:

The maximum SUSTAINABLE power available from ANY air-cooled engine is
determined by the engine's ability to cool itself -- to couple its
waste-heat to the atmosphere. And with a carburetted, spark-ignited,
gasoline-fueled engine there is a LOT of waste heat to be managed
since such engines are no more than 25% efficient when it comes to
converting the heat of combustion into torque at the crankshaft. That
means that for every horsepower measured at the crank you must
generate at least four horsepower's-worth of heat in combustion.
These basic rules of thermodynamics are made even worse by two
additional factors, the first being 'Economy of Scale' in that smaller
engines are LESS thermally efficient than larger engines, and the
basic definition of Standard Day conditions -- 59.9 degrees on the
Fahrenheit scale and an atmospheric pressure of 29.92 inches of
mercury -- a fairly cool day.

With those laws of physics as preamble the next factor worthy of note
is the physical dimensions of the Volkswagen cylinder head and the
fact that ALL VW heads have the same exterior dimensions. This is
because they must fit under the stock VW engine shrouding. No
manufacturer of VW heads, either stock or after-market, offers a head
having more fin area. Indeed, most after-market heads have LESS, due
either to thickening of the combustion chamber wall or even
eliminating one of the eight fins -- and in a few cases they have done
both.

All -- ALL -- Volkswagen heads in common use today are derived from
the heads developed for the 1300cc engine; their external physical
dimensions remained exactly the same for the later 1500 and 1600
engines. The output of the 1300 engine was approximately 40hp and
could SUSTAIN that level of output indefinitely under Standard Day
conditions. This engine was bored-out to 83mm to produce the 1500
engine, then over-bored to 85.5mm to create the 1600 (actual
displacement 1584cc), the maximum output of which was 57bhp for
carburetted models, achieved in the 1971 model year. But that level
of output could only be sustained for a bit less than FOUR MINUTES,
until the cylinder head temperature exceeded safe levels, again under
Standard Day conditions.

So what's this 'safe level' of CHT? About 450 degrees on the
Fahrenheit scale. This reflects the fact that VW heads are made of
CAST aluminum (as opposed to a forging) and the fact aluminum is a
'white short' metal, meaning it becomes frangible when its temperature
enters the 'plastic' range. A characteristic of white-short metals is
that when heated they fracture like a cube of sugar when subjected to
stress. The floor of the frangible range is a bit higher for a
forging -- about 550F according to Pratt-Whitney -- but can be as low
as 400F in a casting, depending upon the alloy.

A common thread used to impress technologically naive buyers is tales
of driving a Volkswagen bug or bus for hours on end with the throttle
wide open. The fact the engine was was probably producing LESS THAN
TWENTY HORSEPOWER goes unsaid. This involves the Horsepower Myth and
generally leaves a large black question mark hanging over the heads of
those without an engineering background but it needs to be touched
upon since ignorance can be as deadly as a machine gun when it comes
to aviation.

The Horsepower Myth was create by James Watt in order to sell his
modified Newcommen steam engine to mine owners. To do so he added the
element of TIME to the power equation and from that day to this the
general public has been comfortable with the idea that 'horsepower'
represents a given quanta of energy... which it does... but only
within a defined unit of TIME. And from that day to this, that
arithmetical loophole has been used by those eager to prey upon
technologically naive consumers.

Indeed, in the early days of aviation those predations cost so many
lives that government agencies had to step in, requiring the
manufacturers of aircraft engines to justify their claims of power and
durability.

------------------------------------------------------

All of which tends to leave the average homebuilder with more
questions than answers. Fortunately, the ENGINES themselves are
incapable of lying, especially when it comes to FUEL CONSUMPTION.

The Specific Fuel Consumption (SFC) of all -- ALL -- air-cooled,
gasoline-fueled, normally aspirated Otto-cycle engines is clumped near
the 0.5 mark, meaning it takes about 0.5 POUNDS of 'gasoline' (*) per
HOUR to produce ONE HORSEPOWER'S worth of torque at the crankshaft.
For aviation gasoline that works out to about 12bhp per gallon per
hour. For a 103hp engine that works out to 8.58 gph.
--------------------------------------------

(*) -- Thanks to additives and dilutants (such as alcohol) gasoline
intended for automobiles has LESS potential energy.

---------------------------------------------

So when someone tries to sell you their Whiz-Bang 103hp VW engine,
simply ask about its fuel consumption. If they give you an honest
answer, such as 'nine gallons per hour' your next question should be
'For what TBO?' (And if they try to feed you the usual '3gph'
bull****, simply walk away.)

The truth is, by simply spinning an engine faster you can claim an
impressive amount of 'horsepower' -- up to 1500bhp for some 'VW'
powered dragsters (but with a TBO measured in MINUTES). Some years
ago turbosupercharged VW engines were all the rage... until people
learned they needed a valve job about every ten hours, no big deal if
you're only SELLING such engines -- but of some importance to the
folks who actually FLY them :-)

-R.S.Hoover

[Bill Daniels]

Well said. Thanks for the sanity.

bildan

> wrote in message
...
>> *******************************************
>> "...the great little VW
>> conversion with a 2.0:1 reduction producing 103 HP."
>> ---------------------------------------------------------
>
> To All:
>
> In the context of an engine converted for flight the figures above are
> wildly fallacious. At best, they represent a 'dyno blip,' at worst
> they may be an out-right lie. Here's why:
>
> The maximum SUSTAINABLE power available from ANY air-cooled engine is
> determined by the engine's ability to cool itself -- to couple its
> waste-heat to the atmosphere. And with a carburetted, spark-ignited,
> gasoline-fueled engine there is a LOT of waste heat to be managed
> since such engines are no more than 25% efficient when it comes to
> converting the heat of combustion into torque at the crankshaft. That
> means that for every horsepower measured at the crank you must
> generate at least four horsepower's-worth of heat in combustion.
> These basic rules of thermodynamics are made even worse by two
> additional factors, the first being 'Economy of Scale' in that smaller
> engines are LESS thermally efficient than larger engines, and the
> basic definition of Standard Day conditions -- 59.9 degrees on the
> Fahrenheit scale and an atmospheric pressure of 29.92 inches of
> mercury -- a fairly cool day.
>
> With those laws of physics as preamble the next factor worthy of note
> is the physical dimensions of the Volkswagen cylinder head and the
> fact that ALL VW heads have the same exterior dimensions. This is
> because they must fit under the stock VW engine shrouding. No
> manufacturer of VW heads, either stock or after-market, offers a head
> having more fin area. Indeed, most after-market heads have LESS, due
> either to thickening of the combustion chamber wall or even
> eliminating one of the eight fins -- and in a few cases they have done
> both.
>
> All -- ALL -- Volkswagen heads in common use today are derived from
> the heads developed for the 1300cc engine; their external physical
> dimensions remained exactly the same for the later 1500 and 1600
> engines. The output of the 1300 engine was approximately 40hp and
> could SUSTAIN that level of output indefinitely under Standard Day
> conditions. This engine was bored-out to 83mm to produce the 1500
> engine, then over-bored to 85.5mm to create the 1600 (actual
> displacement 1584cc), the maximum output of which was 57bhp for
> carburetted models, achieved in the 1971 model year. But that level
> of output could only be sustained for a bit less than FOUR MINUTES,
> until the cylinder head temperature exceeded safe levels, again under
> Standard Day conditions.
>
> So what's this 'safe level' of CHT? About 450 degrees on the
> Fahrenheit scale. This reflects the fact that VW heads are made of
> CAST aluminum (as opposed to a forging) and the fact aluminum is a
> 'white short' metal, meaning it becomes frangible when its temperature
> enters the 'plastic' range. A characteristic of white-short metals is
> that when heated they fracture like a cube of sugar when subjected to
> stress. The floor of the frangible range is a bit higher for a
> forging -- about 550F according to Pratt-Whitney -- but can be as low
> as 400F in a casting, depending upon the alloy.
>
> A common thread used to impress technologically naive buyers is tales
> of driving a Volkswagen bug or bus for hours on end with the throttle
> wide open. The fact the engine was was probably producing LESS THAN
> TWENTY HORSEPOWER goes unsaid. This involves the Horsepower Myth and
> generally leaves a large black question mark hanging over the heads of
> those without an engineering background but it needs to be touched
> upon since ignorance can be as deadly as a machine gun when it comes
> to aviation.
>
> The Horsepower Myth was create by James Watt in order to sell his
> modified Newcommen steam engine to mine owners. To do so he added the
> element of TIME to the power equation and from that day to this the
> general public has been comfortable with the idea that 'horsepower'
> represents a given quanta of energy... which it does... but only
> within a defined unit of TIME. And from that day to this, that
> arithmetical loophole has been used by those eager to prey upon
> technologically naive consumers.
>
> Indeed, in the early days of aviation those predations cost so many
> lives that government agencies had to step in, requiring the
> manufacturers of aircraft engines to justify their claims of power and
> durability.
>
> ------------------------------------------------------
>
> All of which tends to leave the average homebuilder with more
> questions than answers. Fortunately, the ENGINES themselves are
> incapable of lying, especially when it comes to FUEL CONSUMPTION.
>
> The Specific Fuel Consumption (SFC) of all -- ALL -- air-cooled,
> gasoline-fueled, normally aspirated Otto-cycle engines is clumped near
> the 0.5 mark, meaning it takes about 0.5 POUNDS of 'gasoline' (*) per
> HOUR to produce ONE HORSEPOWER'S worth of torque at the crankshaft.
> For aviation gasoline that works out to about 12bhp per gallon per
> hour. For a 103hp engine that works out to 8.58 gph.
> --------------------------------------------
>
> (*) -- Thanks to additives and dilutants (such as alcohol) gasoline
> intended for automobiles has LESS potential energy.
>
> ---------------------------------------------
>
> So when someone tries to sell you their Whiz-Bang 103hp VW engine,
> simply ask about its fuel consumption. If they give you an honest
> answer, such as 'nine gallons per hour' your next question should be
> 'For what TBO?' (And if they try to feed you the usual '3gph'
> bull****, simply walk away.)
>
> The truth is, by simply spinning an engine faster you can claim an
> impressive amount of 'horsepower' -- up to 1500bhp for some 'VW'
> powered dragsters (but with a TBO measured in MINUTES). Some years
> ago turbosupercharged VW engines were all the rage... until people
> learned they needed a valve job about every ten hours, no big deal if
> you're only SELLING such engines -- but of some importance to the
> folks who actually FLY them :-)
>
> -R.S.Hoover

[Gig 601XL Builder[_2_]]

wrote:

> -R.S.Hoover


So how does one start the slow clap on USENET?

Well written.

[Jim Logajan]

" > wrote:
....
> The Horsepower Myth was create by James Watt in order to sell his
> modified Newcommen steam engine to mine owners. To do so he added the
> element of TIME to the power equation
....

It makes no sense to claim "time" was added to the "power" equation because
"power" already is energy per unit time. Perhaps you meant to say time was
added to the "energy" equation?

I'm also not sure what the nature is of the "myth" you are complaining
about. You don't actually make it clear - at least it isn't clear to me.
Just so you know what level to respond at, I managed to somehow get a BSc
in physics, so feel free to use technical terms.

[[email protected]]

On Jan 31, 3:33*pm, Jim Logajan > wrote:
> " > wrote:
>
> ...> The Horsepower Myth was create by James Watt in order to sell his
> > modified Newcommen steam engine to mine owners. To do so he added the
> > element of TIME to the power equation
>
> ...
>
> It makes no sense to claim "time" was added to the "power" equation because
> "power" already is energy per unit time. Perhaps you meant to say time was
> added to the "energy" equation?
>
> I'm also not sure what the nature is of the "myth" you are complaining
> about. You don't actually make it clear - at least it isn't clear to me.
> Just so you know what level to respond at, I managed to somehow get a BSc
> in physics, so feel free to use technical terms.

I don't get that statement either but the SFC is the more important
part. Those numbers add up, such that 3 gph means 36hp. Which veeduber
reports as indefinitely sustainable, which means I guess set the TBO
at what you want (barring other bad signs).

veeduber did I miss it somewhere, or what is the usual CHT of a 1300
sustaining 40hp on a standard day (or any day, that you might have
measured)? That would give a nice reference point to the max temps
given by pratt & whitney.

Is it fair to say that with a particular engine type, that SFC can be
used to estimate HP? (because that's what the equations are doing
seems to me)

Now check this related stuff out from a supplier's website:

Continuous HP, 3400 RPM 80 (note this is 6.6 gph, no?)
Bore (mm) 92
Stroke (mm) 82
Displacement (cc) 2180
Compression Ratio 8.0:1
Idle RPM 700-900
Cruise RPM 3200 +/- 200
Maximum RPM 4000
CHT @ Cruise 350-375 degrees F
CHT @ Climb (5 min) 420 degrees F
CHT Max 450 degrees F

What's the gph figure?

Hmm. Missing ... as is the amount of time that the engine was run to
reach those CHTs ...

Very slick.

[[email protected]]

On Jan 31, 1:33 pm, Jim Logajan > wrote:

> I'm also not sure what the nature is of the "myth" you are complaining
> about.
-----------------------------------------------------------------------------

The one where an articled engineer insists 65hp @ 7200 rpm is exactly
the same as 65hp @ 1800... and equally appropriate for powering a
Piper 'Cub.' (You'll have to go back at least ten years on Usenet if
you want to pick up this particular thread, and to eScribe/Yahoo for
the articles posted to specific Newsgroups.)

In explaining why this was not true -- and in numerous other articles
about VW conversions -- I've used terms appropriate to the reader's
level of understanding... always sure to set an engineer's hair on
fire :-) If you'll take the trouble to read the foundation articles
you will see where the use of valid terms lead to conflicts with what
the typical American homebuilder 'knows.'

-R.S.Hoover

[[email protected]]

On Jan 31, 3:44 pm, wrote:
> what is the usual CHT of a 1300
> sustaining 40hp on a standard day
---------------------------------------------------------------------------------------

I don't know.
The only quantified engine parameters provided by Volkswagen were for
their industrial engines and then only for OT & OP... and only for
color-coded gauges. By comparing the VW gauges to standard gauges
allowed me to define the limits of the arcs. I've posted that
information somewhere (probably on the AirVW Group).

--------------------------------------------------------------------------------------

> (or any day, that you might have
> measured)?

-------------------------------------------------------------------------------------

VDO offered a dealer-installed instrumentation package but the
readings couldn't be trusted due either to improper installation or
depredation of the installation over time. VW issued a couple of
Service Notes pointing out that after-market instrumentation should
not be used for diagnostics unless they had been calibrated.

------------------------------------------------------------------------------------

>That would give a nice reference point to the max temps
> given by pratt & whitney.

------------------------------------------------------------------------------------

With 50W oil and forged heads (vs cast) I don't think such a
comparison would be very wise.

------------------------------------------------------------------------------------

> Now check this related stuff out from a supplier's website:
>
> Continuous HP, 3400 RPM 80 (note this is 6.6 gph, no?)
> Bore (mm) 92
> Stroke (mm) 82
> Displacement (cc) 2180
> Compression Ratio 8.0:1
> Idle RPM 700-900
> Cruise RPM 3200 +/- 200
> Maximum RPM 4000
> CHT @ Cruise 350-375 degrees F
> CHT @ Climb (5 min) 420 degrees F
> CHT Max 450 degrees F
>
-----------------------------------------------------------------------------

There's nothing wrong with the numbers. Dig around the AirVW Group
archives you should find dyno pulls posted by myself and others.
Indeed, the figures are fairly typical for a VW hot-rod engine. Which
of course is the problem.

What's missing are a host of apparently unimportant details, such as
how certain things are measured. By simply locating the CHT sensor to
a cooler location on the head you can 'prove' the engine runs cool.
Ditto for oil temp. A lot of flying VW's are actually measuring the
temperature of the crankcase rather than the oil inside of it. (VW
measured CHT at various locations, depending on the purpose. For
engines converted to flight the best location is the threaded boss
adjacent to the exhaust flange, as provided on a particular model of
cylinder head, which I've shown in several articles. Oil temperature
was measured at the inlet to the oil pump.)

But as I've said before, this is Old News. This ground has been
tilled many times before.

-R.S.Hoover

[[email protected]]

Ted Barker fitted one of his engines to a J3 in the late 60's. It was
a bit sluggish with two on-board but more than adequate when flown
solo. Unfortunately, an ATR with a poor grasp of energy management
augered it in whilst doing aerobatics.

-R.S.Hoover

[cavalamb himself[_2_]]

wrote:
> On Jan 31, 1:33 pm, Jim Logajan > wrote:
>
>
>>I'm also not sure what the nature is of the "myth" you are complaining
>>about.
>
> -----------------------------------------------------------------------------
>
> The one where an articled engineer insists 65hp @ 7200 rpm is exactly
> the same as 65hp @ 1800... and equally appropriate for powering a
> Piper 'Cub.' (You'll have to go back at least ten years on Usenet if
> you want to pick up this particular thread, and to eScribe/Yahoo for
> the articles posted to specific Newsgroups.)
>
> In explaining why this was not true -- and in numerous other articles
> about VW conversions -- I've used terms appropriate to the reader's
> level of understanding... always sure to set an engineer's hair on
> fire :-) If you'll take the trouble to read the foundation articles
> you will see where the use of valid terms lead to conflicts with what
> the typical American homebuilder 'knows.'
>
> -R.S.Hoover
>

Robert,

You will not believe this one. Or - maybe you will?

A VW on a Cub...

Not flying, of course.

http://www.youtube.com/watch?v=BlqVThvkUYM&feature=related

[Steve Foley]

> wrote in message
...
> 'Economy of Scale' in that smaller
> engines are LESS thermally efficient than larger engines

Back before I got thrown out of engineering school, I was taught that if you
double all of the dimensions of something, the volume increases by a factor
of eight, but the surface area only increases by a factor of four.

The question posed was "Is there an upper limit to the size of a bird?" The
answer given, as I remember it was yes. Because the lift of the bird's wings
is proportional to area, but the weight of the bird is proportional to
volume, at some 'size', the wings become overloaded.

The same reasoning was applied to body cooling. The birds cooling was
proportional to surface area, but the heat produced was proportional to
volume.

What did I miss in EE102 after I transferred?

[[email protected]]

Birds aren't engines. See...

http://people.bath.ac.uk/ccsshb/12cyl/

....note the references to the thermal efficiency and specific fuel
consumption of smaller engines.

-R.S.Hoover

[Stealth Pilot[_2_]]

On Thu, 31 Jan 2008 11:28:57 -0800 (PST), "
> wrote:


another aspect of the VW reality that has been alluded to by other
posters, who gave details of the symptoms but seemed unaware of the
causes, is destructive harmonic vibration in the crankshaft.

in the middle of the crankcase is a web that supports the centre
bearing. above that in the middle is a gap where the case and this
centre piece have a hollow part.

in the usual VW car engine the harmonic charactersitics of the
crankshaft are such that the destructive vibration occurs a few
thousand revs above the max possible rpm so the engine never
experiences a problem.

in aircraft installations with large heavy propellors attached to the
shaft the harmonic range occurs at a lower RPM.

particularly with large 3 bladed ground adjustable composite props the
destructive harmonic range comes down to about 3,200rpm. most VW's
would run at around those revs so the problem becomes an unavoidable
one.

the destructive harmonics are indetectable in the cockpit above the
normal engine vibrations but in the engine's interior those harmonics
deliver hammer like blows to the crank web. the hollow area above the
centre of the internal web gets a fair shaking and develops a fine
hairline fatigue crack. this crack leaks copious amounts of oil and of
course there is no way of welding oily electron so the case becomes
junk.

the problem can be avoided completely by using lightweight fixed two
bladed wooden props.

so again there is an upper limit to how much power you can extract
from a VW. a 1600 will be a long lived engine. an 1835 pretty good.
check out how little cylinder wall remains in a 2100 and you'll
probably stck to the more modest displacements.

get the installation right though and the vw will pull the aircraft
around for decades. english Druine Turbulents demonstrate this.

Stealth Pilot

[Steve Foley]

> wrote in message
...
> Birds aren't engines. See...

The same concepts apply. Unfortunately, I was applying the wrong concepts. I
mis-understood the term 'thermal efficiency'.

>
> http://people.bath.ac.uk/ccsshb/12cyl/

That's one nasty engine!

>
> ...note the references to the thermal efficiency and specific fuel
> consumption of smaller engines.

AH HA.

>
> -R.S.Hoover

Thank for the extra help for the slow.

- Steve (Another one not left behind)

[[email protected]]

On Feb 1, 5:29 am, Stealth Pilot >
wrote:

another aspect of the VW reality that has been alluded to by other
posters, who gave details of the symptoms but seemed unaware of the
causes, is destructive harmonic vibration in the crankshaft.
- - - - - - - - - - - - - - - -

Perhaps not.

The VW crankshaft is of the 'boxer' design, where the connecting rod
throws are located in the same plane and symmetrically about the
center main bearing. With the cylinders arranged as opposed pairs
this allows the use of a camshaft having only four lobes. By about
1914 both Porsche and Reimspiess had assembled engines of this
configuration, which was copied by several American engine builders.

By the late 1930's it was understood that the boxer design had a
number of short-comings, one being accelerated wear of the cam, since
each lobe was required to actuate a pair of opposed valves, but also a
curious pattern of wear that appeared in the center main bearing.
Fortunately, these things were relatively easy to fix... unless Hitler
and the Nazi Party happened to be your business partner.

The bottom line is that the Volkswagen engine retained these inherent
flaws whereas the Continental and Lycoming did not.

Advances in metallurgy - specifically, the method of gas-nitriding
cast iron developed by Krupp - eventually resolved the cam-wear
problem but pounding-out of the center main bearing web turned out to
be a flaw inherent with the boxer geometry. Indeed, it was not fully
understood until the mid-1950's when the problem was finally defined
as phlugoid motion generated by the geometry of the VW crankshaft.

The best description of the problem - and to understand the cure - is
to do a side-by-side comparison of a VW and a Subaru crankshaft.

- - - - - - - - - - - - - - - - - - - - - - - - - - -
in the middle of the crankcase is a web that supports the centre
bearing. above that in the middle is a gap where the case and this
centre piece have a hollow part...

....the destructive harmonics are indetectable in the cockpit above
the
normal engine vibrations but in the engine's interior those harmonics
deliver hammer like blows to the crank web. the hollow area above the
centre of the internal web gets a fair shaking and develops a fine
hairline fatigue crack. this crack leaks copious amounts of oil and of
course there is no way of welding oily electron so the case becomes
junk.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

I'm afraid I can't quite follow that. I've uploaded some pix of the
center main bearing web to my blog...

http://bobhooversblog.blogspot.com/

.....that may help you to see why I don't understand your description
of where your crack occurred.

Other than cracks resulting from catastrophic failures such as a
thrown rod, the only cracks I've seen in the vicinity of the center
main bearing web have been the product of shoddy machine work, either
due to improper clearencing or using cutting tools having the wrong
radius.

Another factor is where - and how - the propeller is attached to the
crankshaft, specifically with regard to the THRUST BEARING.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

.....particularly with large 3 bladed ground adjustable composite props
the
destructive harmonic range comes down to about 3,200rpm. most VW's
would run at around those revs so the problem becomes an unavoidable
one.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Again, perhaps not.

The only reason for running the engine at that rpm is because most
flying Volkswagens are fitted with hot-rod cams. If you retain the
stock cam and simply retard it by four degrees you will move the
torque-peak to about 1800rpm. By then adjusting the displacement and
compression ratio in keeping with the thermal limitations of the
cylinder heads, you will have a sturdy, reliable, DURABLE engine
capable of delivering in excess of 75hp @ 2750rpm for take-off and
about 40hp for cruise.

But such an engine is a far cry from the dune-buggy mentality on which
most flying VW's are based.

As for your mention of cylinder wall thickness, apparently as a
limitation to power output, the wall of a 94mm barrel is actually
thicker than that of the typical 92mm barrel. But the real problem
isn't the thickness of the wall but the competence of the SEAL between
the wall and the cylinder head. Proper assembly and the use of fully
annealed copper seals makes this a non-issue, assuming the compression
ratio is within reason.

I'm sorry your engine suffered a crack but I've a hunch you'll find a
lot more reasons for it before you work your way down to something as
exotic as 'crankshaft harmonics,' although this may be only a
difference of terms.

-R.S.Hoover

[John[_14_]]

wrote:

>
> Is it fair to say that with a particular engine type, that SFC can be
> used to estimate HP? (because that's what the equations are doing
> seems to me)
>


Varies somewhat with an engine's efficiency. Most normally aspirated
air cooled engines are in the .42 to .45 range. That's leaned out to
best efficiency remember. Car engines are I believe, around or little
under .4 by using electronic fuel injection and low friction (narrow)
bearings etc. and the more efficient diesels in the mid .3s. IIRC, the
turbocompound radials like the R3360 were in the high .3s, among the
most efficient gas engines built, even if they didn't run like that very
long before something went south.

I think .45 lb/hp/hr will give a valid fuel consumption number, accurate
to a few percent, for pretty much any power setting that can be done at
lean mixture on just about any gasoline air cooled, carburated engine.

John

[Blueskies]

> wrote in message ...
>> *******************************************
>> "...the great little VW
>> conversion with a 2.0:1 reduction producing 103 HP."
>> ---------------------------------------------------------
>
> To All:
>
> In the context of an engine converted for flight the figures above are
> wildly fallacious. At best, they represent a 'dyno blip,' at worst
> they may be an out-right lie. Here's why:
>
> The maximum SUSTAINABLE power available from ANY air-cooled engine is
> determined by the engine's ability to cool itself -- to couple its
> waste-heat to the atmosphere. And with a carburetted, spark-ignited,
> gasoline-fueled engine there is a LOT of waste heat to be managed
> since such engines are no more than 25% efficient when it comes to
> converting the heat of combustion into torque at the crankshaft. That
> means that for every horsepower measured at the crank you must
> generate at least four horsepower's-worth of heat in combustion.
> These basic rules of thermodynamics are made even worse by two
> additional factors, the first being 'Economy of Scale' in that smaller
> engines are LESS thermally efficient than larger engines, and the
> basic definition of Standard Day conditions -- 59.9 degrees on the
> Fahrenheit scale and an atmospheric pressure of 29.92 inches of
> mercury -- a fairly cool day.
>
> With those laws of physics as preamble the next factor worthy of note
> is the physical dimensions of the Volkswagen cylinder head and the
> fact that ALL VW heads have the same exterior dimensions. This is
> because they must fit under the stock VW engine shrouding. No
> manufacturer of VW heads, either stock or after-market, offers a head
> having more fin area. Indeed, most after-market heads have LESS, due
> either to thickening of the combustion chamber wall or even
> eliminating one of the eight fins -- and in a few cases they have done
> both.
>
> All -- ALL -- Volkswagen heads in common use today are derived from
> the heads developed for the 1300cc engine; their external physical
> dimensions remained exactly the same for the later 1500 and 1600
> engines. The output of the 1300 engine was approximately 40hp and
> could SUSTAIN that level of output indefinitely under Standard Day
> conditions. This engine was bored-out to 83mm to produce the 1500
> engine, then over-bored to 85.5mm to create the 1600 (actual
> displacement 1584cc), the maximum output of which was 57bhp for
> carburetted models, achieved in the 1971 model year. But that level
> of output could only be sustained for a bit less than FOUR MINUTES,
> until the cylinder head temperature exceeded safe levels, again under
> Standard Day conditions.
>
> So what's this 'safe level' of CHT? About 450 degrees on the
> Fahrenheit scale. This reflects the fact that VW heads are made of
> CAST aluminum (as opposed to a forging) and the fact aluminum is a
> 'white short' metal, meaning it becomes frangible when its temperature
> enters the 'plastic' range. A characteristic of white-short metals is
> that when heated they fracture like a cube of sugar when subjected to
> stress. The floor of the frangible range is a bit higher for a
> forging -- about 550F according to Pratt-Whitney -- but can be as low
> as 400F in a casting, depending upon the alloy.
>
> A common thread used to impress technologically naive buyers is tales
> of driving a Volkswagen bug or bus for hours on end with the throttle
> wide open. The fact the engine was was probably producing LESS THAN
> TWENTY HORSEPOWER goes unsaid. This involves the Horsepower Myth and
> generally leaves a large black question mark hanging over the heads of
> those without an engineering background but it needs to be touched
> upon since ignorance can be as deadly as a machine gun when it comes
> to aviation.
>
> The Horsepower Myth was create by James Watt in order to sell his
> modified Newcommen steam engine to mine owners. To do so he added the
> element of TIME to the power equation and from that day to this the
> general public has been comfortable with the idea that 'horsepower'
> represents a given quanta of energy... which it does... but only
> within a defined unit of TIME. And from that day to this, that
> arithmetical loophole has been used by those eager to prey upon
> technologically naive consumers.
>
> Indeed, in the early days of aviation those predations cost so many
> lives that government agencies had to step in, requiring the
> manufacturers of aircraft engines to justify their claims of power and
> durability.
>
> ------------------------------------------------------
>
> All of which tends to leave the average homebuilder with more
> questions than answers. Fortunately, the ENGINES themselves are
> incapable of lying, especially when it comes to FUEL CONSUMPTION.
>
> The Specific Fuel Consumption (SFC) of all -- ALL -- air-cooled,
> gasoline-fueled, normally aspirated Otto-cycle engines is clumped near
> the 0.5 mark, meaning it takes about 0.5 POUNDS of 'gasoline' (*) per
> HOUR to produce ONE HORSEPOWER'S worth of torque at the crankshaft.
> For aviation gasoline that works out to about 12bhp per gallon per
> hour. For a 103hp engine that works out to 8.58 gph.
> --------------------------------------------
>
> (*) -- Thanks to additives and dilutants (such as alcohol) gasoline
> intended for automobiles has LESS potential energy.
>
> ---------------------------------------------
>
> So when someone tries to sell you their Whiz-Bang 103hp VW engine,
> simply ask about its fuel consumption. If they give you an honest
> answer, such as 'nine gallons per hour' your next question should be
> 'For what TBO?' (And if they try to feed you the usual '3gph'
> bull****, simply walk away.)
>
> The truth is, by simply spinning an engine faster you can claim an
> impressive amount of 'horsepower' -- up to 1500bhp for some 'VW'
> powered dragsters (but with a TBO measured in MINUTES). Some years
> ago turbosupercharged VW engines were all the rage... until people
> learned they needed a valve job about every ten hours, no big deal if
> you're only SELLING such engines -- but of some importance to the
> folks who actually FLY them :-)
>
> -R.S.Hoover



We made 11.89 in a 1/4 mile with our 1800cc 'dragster' Ghia, quad carbs and total run time of minutes before complete
teardown and rebuild. Fun, but would never go in a plane. We did not have a dyno but it sure ran nice! The 1800cc did
better than the 2180...

[Stealth Pilot[_2_]]

Bob
Aeropower here in Perth was an aero engine conversion business run by
Sig Muninger and his dad as an adjunct to a healthy VW car overhaul
business. ....probably about 10 years ago.
The problem caused a string of failures in aeropower conversions.
identifying and solving the problem cost Sig over $100,000.
The problem and the work involved in identifying it's cause were
explained to me by Sig himself as we stood beside the test rig.

what can I say?
Your mileage may vary.

just dont stick a heavy prop on your conversion.

Stealth Pilot




On Fri, 1 Feb 2008 13:10:58 -0800 (PST), "
> wrote:

>On Feb 1, 5:29 am, Stealth Pilot >
>wrote:
>
>another aspect of the VW reality that has been alluded to by other
>posters, who gave details of the symptoms but seemed unaware of the
>causes, is destructive harmonic vibration in the crankshaft.
>- - - - - - - - - - - - - - - -
>
>Perhaps not.
>
>The VW crankshaft is of the 'boxer' design, where the connecting rod
>throws are located in the same plane and symmetrically about the
>center main bearing. With the cylinders arranged as opposed pairs
>this allows the use of a camshaft having only four lobes. By about
>1914 both Porsche and Reimspiess had assembled engines of this
>configuration, which was copied by several American engine builders.
>
>By the late 1930's it was understood that the boxer design had a
>number of short-comings, one being accelerated wear of the cam, since
>each lobe was required to actuate a pair of opposed valves, but also a
>curious pattern of wear that appeared in the center main bearing.
>Fortunately, these things were relatively easy to fix... unless Hitler
>and the Nazi Party happened to be your business partner.
>
>The bottom line is that the Volkswagen engine retained these inherent
>flaws whereas the Continental and Lycoming did not.
>
>Advances in metallurgy - specifically, the method of gas-nitriding
>cast iron developed by Krupp - eventually resolved the cam-wear
>problem but pounding-out of the center main bearing web turned out to
>be a flaw inherent with the boxer geometry. Indeed, it was not fully
>understood until the mid-1950's when the problem was finally defined
>as phlugoid motion generated by the geometry of the VW crankshaft.
>
>The best description of the problem - and to understand the cure - is
>to do a side-by-side comparison of a VW and a Subaru crankshaft.
>
>- - - - - - - - - - - - - - - - - - - - - - - - - - -
>in the middle of the crankcase is a web that supports the centre
>bearing. above that in the middle is a gap where the case and this
>centre piece have a hollow part...
>
>...the destructive harmonics are indetectable in the cockpit above
>the
>normal engine vibrations but in the engine's interior those harmonics
>deliver hammer like blows to the crank web. the hollow area above the
>centre of the internal web gets a fair shaking and develops a fine
>hairline fatigue crack. this crack leaks copious amounts of oil and of
>course there is no way of welding oily electron so the case becomes
>junk.
>
>- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
>I'm afraid I can't quite follow that. I've uploaded some pix of the
>center main bearing web to my blog...
>
>http://bobhooversblog.blogspot.com/
>
>....that may help you to see why I don't understand your description
>of where your crack occurred.
>
>Other than cracks resulting from catastrophic failures such as a
>thrown rod, the only cracks I've seen in the vicinity of the center
>main bearing web have been the product of shoddy machine work, either
>due to improper clearencing or using cutting tools having the wrong
>radius.
>
>Another factor is where - and how - the propeller is attached to the
>crankshaft, specifically with regard to the THRUST BEARING.
>
>- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
>....particularly with large 3 bladed ground adjustable composite props
>the
>destructive harmonic range comes down to about 3,200rpm. most VW's
>would run at around those revs so the problem becomes an unavoidable
>one.
>
>- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
>Again, perhaps not.
>
>The only reason for running the engine at that rpm is because most
>flying Volkswagens are fitted with hot-rod cams. If you retain the
>stock cam and simply retard it by four degrees you will move the
>torque-peak to about 1800rpm. By then adjusting the displacement and
>compression ratio in keeping with the thermal limitations of the
>cylinder heads, you will have a sturdy, reliable, DURABLE engine
>capable of delivering in excess of 75hp @ 2750rpm for take-off and
>about 40hp for cruise.
>
>But such an engine is a far cry from the dune-buggy mentality on which
>most flying VW's are based.
>
>As for your mention of cylinder wall thickness, apparently as a
>limitation to power output, the wall of a 94mm barrel is actually
>thicker than that of the typical 92mm barrel. But the real problem
>isn't the thickness of the wall but the competence of the SEAL between
>the wall and the cylinder head. Proper assembly and the use of fully
>annealed copper seals makes this a non-issue, assuming the compression
>ratio is within reason.
>
>I'm sorry your engine suffered a crack but I've a hunch you'll find a
>lot more reasons for it before you work your way down to something as
>exotic as 'crankshaft harmonics,' although this may be only a
>difference of terms.
>
>-R.S.Hoover

[Stealth Pilot[_2_]]

On Thu, 31 Jan 2008 11:28:57 -0800 (PST), "
> wrote:


Bob I admire your work so I'm going to irritate you with an argument.
I wish someone would post a concise guide to a style of VW conversion
that is durable and simple. have never seen one that had the tests of
time behind it. 1600 or 1835cc for preference.

as to the hollow part...
in your blog page top photo look at the left side rusty stud.
look just to the left of that stud and you'll see an area where the
metal that the stud screws into doesnt extend to the case outer side.
that is the hollow part I was referring to. bad terminology??

the cracks that occurred in Sig's cases were in the centre of the case
top just to one side of centre. it's the common crack area I believe.

btw to continue your rib baking experiment you should read up the Molt
Taylor, Jerry Holcombe experiments on TPG (Taylor Paper Glass).
they used a medium thickness kraft paper. seems like the stuff that
some paper gaskets are made of. Btw commercial Laminex is/was just
paper sheets and epoxy.the top paper sheet is printed with the
pattern.

keep up the good work. enjoy your posts.
Stealth Pilot

[cavalamb himself[_2_]]

Stealth Pilot wrote:
> Bob
> Aeropower here in Perth was an aero engine conversion business run by
> Sig Muninger and his dad as an adjunct to a healthy VW car overhaul
> business. ....probably about 10 years ago.
> The problem caused a string of failures in aeropower conversions.
> identifying and solving the problem cost Sig over $100,000.
> The problem and the work involved in identifying it's cause were
> explained to me by Sig himself as we stood beside the test rig.
>
> what can I say?
> Your mileage may vary.
>
> just dont stick a heavy prop on your conversion.
>
> Stealth Pilot
>
>

Was he trying to use metal props?

Or cast cranks?

[Stealth Pilot[_2_]]

On Sat, 02 Feb 2008 12:56:55 -0800, cavalamb himself
> wrote:

>Stealth Pilot wrote:
>> Bob
>> Aeropower here in Perth was an aero engine conversion business run by
>> Sig Muninger and his dad as an adjunct to a healthy VW car overhaul
>> business. ....probably about 10 years ago.
>> The problem caused a string of failures in aeropower conversions.
>> identifying and solving the problem cost Sig over $100,000.
>> The problem and the work involved in identifying it's cause were
>> explained to me by Sig himself as we stood beside the test rig.
>>
>> what can I say?
>> Your mileage may vary.
>>
>> just dont stick a heavy prop on your conversion.
>>
>> Stealth Pilot
>>
>>
>
>Was he trying to use metal props?
>
>Or cast cranks?

neither.
Stealth Pilot

[[email protected]]

On Feb 2, 5:48 am, Stealth Pilot >
wrote:

> Bob I admire your work so I'm going to irritate you with an argument.
> I wish someone would post a concise guide to a style of VW conversion
> that is durable and simple. have never seen one that had the tests of
> time behind it. 1600 or 1835cc for preference.
> -------------------------------------------------------------------------

Dear Stealth,

Allow me to share with you something I just saw on the internet. Some
old geezer said:

"As far back as Rockford, at least three builders of converted VW's
appealed to Pope Paul to use the EAA's bully pulpit for educating
homebuilders about the realities of automobile engine conversions. At
least two of us (me and Ted Barker) even offered to provide the
required torque-stand. But the EAA was (and is) more interested in
selling tent-space and full-page ads than in contributing to the basic
store of USEFUL homebuilt information."

Ain't that a hoot? Stupid ol' fool actually thought the EAA was about
doing something USEFUL, like, mebbe, what you said up there at the
top.

-R.S.Hoover

[RST Engineering]

I could be very, very wrong, but my understanding of efficiency is that 25%
efficiency means that a quarter of the energy goes to torque and 3/4 to
heat. That would mean you throw away THREE horsepower's-worth instead of
four, no?

Jim



> since such engines are no more than 25% efficient when it comes to
> converting the heat of combustion into torque at the crankshaft. That
> means that for every horsepower measured at the crank you must
> generate at least four horsepower's-worth of heat in combustion.

[Charles Vincent]

RST Engineering wrote:
> I could be very, very wrong, but my understanding of efficiency is that 25%
> efficiency means that a quarter of the energy goes to torque and 3/4 to
> heat. That would mean you throw away THREE horsepower's-worth instead of
> four, no?
>
> Jim
>
>
>
>> since such engines are no more than 25% efficient when it comes to
>> converting the heat of combustion into torque at the crankshaft. That
>> means that for every horsepower measured at the crank you must
>> generate at least four horsepower's-worth of heat in combustion.
>
>
You are correct, but that is also exactly what he said ---. i.e.
generate four hp in heat, only one available at the shaft.

Charles

[Peter Dohm]

"Charles Vincent" > wrote in message
t...
> RST Engineering wrote:
>> I could be very, very wrong, but my understanding of efficiency is that
>> 25% efficiency means that a quarter of the energy goes to torque and 3/4
>> to heat. That would mean you throw away THREE horsepower's-worth instead
>> of four, no?
>>
>> Jim
>>
>>
>>
>>> since such engines are no more than 25% efficient when it comes to
>>> converting the heat of combustion into torque at the crankshaft. That
>>> means that for every horsepower measured at the crank you must
>>> generate at least four horsepower's-worth of heat in combustion.
>>
>>
> You are correct, but that is also exactly what he said ---. i.e. generate
> four hp in heat, only one available at the shaft.
>
> Charles

Well, with only slight rephrasing, that is what was said at the beginning of
this thread. The rephrasing would be that we "throw away 3 horespower's
worth of heat out of every four".

Actually, that is slightly worse than I was taught; but I really did not
regard it as the primary issue under discussion--so I let it be. The number
that I was taught a little more than 40 years ago was 30% when running at a
moderately high percentage of power. I understand that there has been
considerable improvement since then, which could have brought the efficiency
up to around 33%, and I have read recently (from a forgotten source) that
the theoretical maximum is around 37% efficience for spark ignition engines.

So, for the moment, it is unclear (at least to me) whether the 25% figure is
slightly low, pertains to rich mixture opperation, or is related to the low
compression and the intake and exhaust plumbing of the engines in question.
In any case, even the 25% figure is really much better than we can obtain
from our supposedly more efficient automobile engines--especially when you
consider the waste in time spent idling or simply "spun up" to avoid lugging
(because the cost of not doing so is far greater).

However, the basic point of Bob's original post is very real; even on the
highway, cars and trucks normally run at a very low percentage of power--and
the few exceptions, such as pulling trailers far about the rated limit, seem
to result in increased failure rates and short TBOs.

I admit that I still believe a 1600, and especially an 1800, is fully
capable of producing 60 hp on takeoff and 30 hp in cruise with a 52 inch
diameter prop--and that the addition of thermal barrier and dispersant
coatings might allow a climb power approaching 40 hp. But none of that
detracts from the basic points--that cars and trucks normally opperate at
surprisingly low ower levels, and that 100 maximum continuous hp from a
Continental O-200 really does mean continuous. Taken in that context, tha
1600 might well be 40 hp maximum and 30 hp cruise; and the thermal coatings
might raise that to 45 hp maximum and 33 hp cruise.

Peter
(Former engineering student and shade-tree mechanic)

[[email protected]]

On Feb 4, 12:23 pm, "Peter Dohm" > wrote:

> I still believe a 1600...

------------------------------------------------------------------------------

That'll make a fine epitaph.

An engine doesn't give a **** what you believe. Nor what some
huckster has told a tent-full of the faithful to separate them from
their money. Engines are painfully honest -- often fatally so.

Build a few. Put your beliefs aside and listen to what the ENGINE has
to say.

-R.S.Hoover

[cavalamb himself[_2_]]

Peter Dohm wrote:
> "Charles Vincent" > wrote in message
> t...
>
>>RST Engineering wrote:
>>
>>>I could be very, very wrong, but my understanding of efficiency is that
>>>25% efficiency means that a quarter of the energy goes to torque and 3/4
>>>to heat. That would mean you throw away THREE horsepower's-worth instead
>>>of four, no?
>>>
>>>Jim
>>>
>>>
>>>
>>>
>>>>since such engines are no more than 25% efficient when it comes to
>>>>converting the heat of combustion into torque at the crankshaft. That
>>>>means that for every horsepower measured at the crank you must
>>>>generate at least four horsepower's-worth of heat in combustion.
>>>
>>>
>>You are correct, but that is also exactly what he said ---. i.e. generate
>>four hp in heat, only one available at the shaft.
>>
>>Charles
>
>
> Well, with only slight rephrasing, that is what was said at the beginning of
> this thread. The rephrasing would be that we "throw away 3 horespower's
> worth of heat out of every four".
>
> Actually, that is slightly worse than I was taught; but I really did not
> regard it as the primary issue under discussion--so I let it be. The number
> that I was taught a little more than 40 years ago was 30% when running at a
> moderately high percentage of power. I understand that there has been
> considerable improvement since then, which could have brought the efficiency
> up to around 33%, and I have read recently (from a forgotten source) that
> the theoretical maximum is around 37% efficience for spark ignition engines.
>
> So, for the moment, it is unclear (at least to me) whether the 25% figure is
> slightly low, pertains to rich mixture opperation, or is related to the low
> compression and the intake and exhaust plumbing of the engines in question.
> In any case, even the 25% figure is really much better than we can obtain
> from our supposedly more efficient automobile engines--especially when you
> consider the waste in time spent idling or simply "spun up" to avoid lugging
> (because the cost of not doing so is far greater).
>
> However, the basic point of Bob's original post is very real; even on the
> highway, cars and trucks normally run at a very low percentage of power--and
> the few exceptions, such as pulling trailers far about the rated limit, seem
> to result in increased failure rates and short TBOs.
>
> I admit that I still believe a 1600, and especially an 1800, is fully
> capable of producing 60 hp on takeoff and 30 hp in cruise with a 52 inch
> diameter prop--and that the addition of thermal barrier and dispersant
> coatings might allow a climb power approaching 40 hp. But none of that
> detracts from the basic points--that cars and trucks normally opperate at
> surprisingly low ower levels, and that 100 maximum continuous hp from a
> Continental O-200 really does mean continuous. Taken in that context, tha
> 1600 might well be 40 hp maximum and 30 hp cruise; and the thermal coatings
> might raise that to 45 hp maximum and 33 hp cruise.
>
> Peter
> (Former engineering student and shade-tree mechanic)
>
>


That (the last paragraph) does seem to agree pretty well with my results.

For whatever that's worth...


Richard

[Peter Dohm]

> wrote in message
...
> On Feb 4, 12:23 pm, "Peter Dohm" > wrote:
>
>> I still believe a 1600...
>
> ------------------------------------------------------------------------------
>
> That'll make a fine epitaph.
>
> An engine doesn't give a **** what you believe. Nor what some
> huckster has told a tent-full of the faithful to separate them from
> their money. Engines are painfully honest -- often fatally so.
>
> Build a few. Put your beliefs aside and listen to what the ENGINE has
> to say.
>
> -R.S.Hoover

Sorry to have upset you.

Peter

[Peter Dohm]

"cavalamb himself" > wrote in message
...
> Peter Dohm wrote:
-----------------much snipped--------------
>>
>> I admit that I still believe a 1600, and especially an 1800, is fully
>> capable of producing 60 hp on takeoff and 30 hp in cruise with a 52 inch
>> diameter prop--and that the addition of thermal barrier and dispersant
>> coatings might allow a climb power approaching 40 hp. But none of that
>> detracts from the basic points--that cars and trucks normally opperate at
>> surprisingly low ower levels, and that 100 maximum continuous hp from a
>> Continental O-200 really does mean continuous. Taken in that context,
>> tha 1600 might well be 40 hp maximum and 30 hp cruise; and the thermal
>> coatings might raise that to 45 hp maximum and 33 hp cruise.
>>
>> Peter
>> (Former engineering student and shade-tree mechanic)
>>
>>
>
>
> That (the last paragraph) does seem to agree pretty well with my results.
>
> For whatever that's worth...
>
>
> Richard
>
Actually, it's worth a great deal because it provides further confirmation
for the maximum continuous power; and does so within a range of speeds that
approximate maximum performance climb for a lot of small experimentals.
That's probably about as close as it gets for a useable rull of thumb.

BTW, it seems to me that they are not that far from Veeduber's maximum
continuous numbers.

Peter

[Bill Daniels]

Way back when I was a university student I got stuck fixing a girlfriends VW
"Bug". (I think she liked the Bug more than me but kept me around 'cause I
could fix it.) From that experience I developed a strong dislike for the
"Bug". My Volvo 544 was both more comfortable and more reliable while
providing about the same gas milage.

Once while chasing VW parts in the Volvo (Never happened the other way
'round) I struck up a conversation with a German mechanic at a VW shop.
Refering to the little flat 4, he said, "Well, it was a good idea when it
made 36HP - not so good when they increased the power. "What do you
drive?", I asked. He pointed to a brand new Caddy and gave me a slow wink.

If you want a light weight engine why not look hard at state of the art
Japanese "liter bike" engines instead of a 60 year old VW design? My
Kawasaki cranks out 108HP and is reputed to be bulletproof. Of course a
PRSU would be manditory given that the little Kawi would be turning almost
9,000 RPM.

Somebody made a 2.8 liter V8 out of a pair of Hyabusa cylinder blocks.
Making a flat 4 shouldn't be any harder.
See: http://thekneeslider.com/archives/2005/02/09/hayabusa-v8-engine/

[clare at snyder.on.ca]

On Mon, 04 Feb 2008 13:06:29 -0600, Charles Vincent
> wrote:

>RST Engineering wrote:
>> I could be very, very wrong, but my understanding of efficiency is that 25%
>> efficiency means that a quarter of the energy goes to torque and 3/4 to
>> heat. That would mean you throw away THREE horsepower's-worth instead of
>> four, no?
>>
>> Jim
>>
>>
>>
>>> since such engines are no more than 25% efficient when it comes to
>>> converting the heat of combustion into torque at the crankshaft. That
>>> means that for every horsepower measured at the crank you must
>>> generate at least four horsepower's-worth of heat in combustion.
>>
>>
>You are correct, but that is also exactly what he said ---. i.e.
>generate four hp in heat, only one available at the shaft.
>
>Charles
What he's forgetting is the 1 available at the shaft is STILL heat
energy.
Fuel makes 4
Pistons catch 1
cooling and exhaust loose the other 3.


--
Posted via a free Usenet account from http://www.teranews.com

[Peter Dohm]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
...
> Way back when I was a university student I got stuck fixing a girlfriends
> VW "Bug". (I think she liked the Bug more than me but kept me around
> 'cause I could fix it.) From that experience I developed a strong dislike
> for the "Bug". My Volvo 544 was both more comfortable and more reliable
> while providing about the same gas milage.
>
> Once while chasing VW parts in the Volvo (Never happened the other way
> 'round) I struck up a conversation with a German mechanic at a VW shop.
> Refering to the little flat 4, he said, "Well, it was a good idea when it
> made 36HP - not so good when they increased the power. "What do you
> drive?", I asked. He pointed to a brand new Caddy and gave me a slow
> wink.
>
> If you want a light weight engine why not look hard at state of the art
> Japanese "liter bike" engines instead of a 60 year old VW design? My
> Kawasaki cranks out 108HP and is reputed to be bulletproof. Of course a
> PRSU would be manditory given that the little Kawi would be turning almost
> 9,000 RPM.
>
> Somebody made a 2.8 liter V8 out of a pair of Hyabusa cylinder blocks.
> Making a flat 4 shouldn't be any harder.
> See: http://thekneeslider.com/archives/2005/02/09/hayabusa-v8-engine/
>
Well, to be blunt, I am not into *that* level of experimenting any time
soon.

Basically, the VW is such an old standard that I couldn't resist asking a
few questions and mentioning some of what I have seen. And, of course,
there is plain old nostalgia. Back in the day, VW engines were so cheap and
plentifull that they were irresistable, and a lot of entry level
experimentals were designed around them for that reason--just as some were
designed around the Model A Ford engine decades earlier.

They are still a reasonable choice on a few, mostly single seaters; but, in
the end, it has mostly served to show me why they have been replaced by
Corvair, Jabiru and Rotax engines on several of the common 2 seat airframes.

BTW, reduction drives are not a panacea. They do add maintenance and
complexity--especially for a home brew project.

Peter

[clare at snyder.on.ca]

On Mon, 4 Feb 2008 15:23:43 -0500, "Peter Dohm"
> wrote:


>
>I admit that I still believe a 1600, and especially an 1800, is fully
>capable of producing 60 hp on takeoff and 30 hp in cruise with a 52 inch
>diameter prop--and that the addition of thermal barrier and dispersant
>coatings might allow a climb power approaching 40 hp. But none of that
>detracts from the basic points--that cars and trucks normally opperate at
>surprisingly low ower levels, and that 100 maximum continuous hp from a
>Continental O-200 really does mean continuous. Taken in that context, tha
>1600 might well be 40 hp maximum and 30 hp cruise; and the thermal coatings
>might raise that to 45 hp maximum and 33 hp cruise.
>
>Peter
>(Former engineering student and shade-tree mechanic)
>
Except for the FACT that it is a rare O-200 that will produce an
honest 100HP under "standard conditions" in stock form, and on an
average day, in average conditions in most of the continental US, 90%
would be doing good on the ground - less in the air.

--
Posted via a free Usenet account from http://www.teranews.com

[[email protected]]

On Feb 5, 8:07*pm, "Bill Daniels" <bildan@comcast-dot-net> wrote:
> Way back when I was a university student I got stuck fixing a girlfriends VW
> "Bug". *(I think she liked the Bug more than me but kept me around 'cause I
> could fix it.) *From that experience I developed a strong dislike for the
> "Bug". *My Volvo 544 was both more comfortable and more reliable while
> providing about the same gas milage.
>
> Once while chasing VW parts in the Volvo (Never happened the other way
> 'round) I struck up a conversation with a German mechanic at a VW shop.
> Refering to the little flat 4, he said, "Well, it was a good idea when it
> made 36HP - not so good when they increased the power. *"What do you
> drive?", I asked. *He pointed to a brand new Caddy and gave me a slow wink.
>
> If you want a light weight engine why not look hard at state of the art
> Japanese "liter bike" engines instead of a 60 year old VW design? *My
> Kawasaki cranks out 108HP and is reputed to be bulletproof. *Of course a
> PRSU would be manditory given that the little Kawi would be turning almost
> 9,000 RPM.
>
> Somebody made a 2.8 liter V8 out of a pair of Hyabusa cylinder blocks.
> Making a flat 4 shouldn't be any harder.
> See:http://thekneeslider.com/archives/2005/02/09/hayabusa-v8-engine/

some in Deutschland have built aero conversions out of BMW R series
engines.

most of the HP from those japanese engines comes at very high rpm --
have to develop a very solid PSRU for that ... and there's nobody
flying these things, which means you'd be a real guinea pig. But, I
say if you've really thought it through, and done a lot of testing,
bike engine might turn out to work (but only with a really bullet
proof PSRU)

[John[_14_]]

Charles Vincent wrote:
> RST Engineering wrote:
>> I could be very, very wrong, but my understanding of efficiency is
>> that 25% efficiency means that a quarter of the energy goes to torque
>> and 3/4 to heat. That would mean you throw away THREE
>> horsepower's-worth instead of four, no?
>>
>> Jim
>>
>>
>>
>>> since such engines are no more than 25% efficient when it comes to
>>> converting the heat of combustion into torque at the crankshaft. That
>>> means that for every horsepower measured at the crank you must
>>> generate at least four horsepower's-worth of heat in combustion.
>>
>>
> You are correct, but that is also exactly what he said ---. i.e.
> generate four hp in heat, only one available at the shaft.
>
> Charles


Well that's better than a 100 watt electric light bulb, which is a 90
watt heater and 10 watt light source...

John

[Bill Daniels]

> wrote in message
...
On Feb 5, 8:07 pm, "Bill Daniels" <bildan@comcast-dot-net> wrote:
> Way back when I was a university student I got stuck fixing a girlfriends
> VW
> "Bug". (I think she liked the Bug more than me but kept me around 'cause I
> could fix it.) From that experience I developed a strong dislike for the
> "Bug". My Volvo 544 was both more comfortable and more reliable while
> providing about the same gas milage.
>
> Once while chasing VW parts in the Volvo (Never happened the other way
> 'round) I struck up a conversation with a German mechanic at a VW shop.
> Refering to the little flat 4, he said, "Well, it was a good idea when it
> made 36HP - not so good when they increased the power. "What do you
> drive?", I asked. He pointed to a brand new Caddy and gave me a slow wink.
>
> If you want a light weight engine why not look hard at state of the art
> Japanese "liter bike" engines instead of a 60 year old VW design? My
> Kawasaki cranks out 108HP and is reputed to be bulletproof. Of course a
> PRSU would be manditory given that the little Kawi would be turning almost
> 9,000 RPM.
>
> Somebody made a 2.8 liter V8 out of a pair of Hyabusa cylinder blocks.
> Making a flat 4 shouldn't be any harder.
> See:http://thekneeslider.com/archives/2005/02/09/hayabusa-v8-engine/

some in Deutschland have built aero conversions out of BMW R series
engines.

most of the HP from those japanese engines comes at very high rpm --
have to develop a very solid PSRU for that ... and there's nobody
flying these things, which means you'd be a real guinea pig. But, I
say if you've really thought it through, and done a lot of testing,
bike engine might turn out to work (but only with a really bullet
proof PSRU)

Well, I'm not going to build a Hyabusa flat 8 but if I were, I'd be thinking
about a planetary gear PSRU. Planetarys have a lot of gear tooth engagement
and are happy with high RPM sun gears. A fairly small planetary can get 4:1
reduction which would reduce 9000RPM to a very usable 2250.

The propeller thrust bearings would be on the ring gear - the engine
crankshaft would see only torque loads. This little screamer would produce
about 280HP in stock trim from an engine about the size of an O-200.

Bill D

[Anthony W]

Bill Daniels wrote:

> Well, I'm not going to build a Hyabusa flat 8 but if I were, I'd be thinking
> about a planetary gear PSRU. Planetarys have a lot of gear tooth engagement
> and are happy with high RPM sun gears. A fairly small planetary can get 4:1
> reduction which would reduce 9000RPM to a very usable 2250.
>
> The propeller thrust bearings would be on the ring gear - the engine
> crankshaft would see only torque loads. This little screamer would produce
> about 280HP in stock trim from an engine about the size of an O-200.
>
> Bill D

I think we would be back to the same problem, the engine can't dissipate
that much heat. Motorcycles don't run at peak output any more than car
engines do and the sustainable power level would be considerably lower.
Not that a Suzuki V8 wouldn't be fun, I don't think it has what it
takes to be a good aircraft engine.

The more I think about it, the less I think any auto engine conversion
is going to do the job well. I'm looking for an old but rebuildable
airplane engine that I can rebuild rather than spend all my money on an
engine I can't trust. I don't mind it not having the certificate and I
don't think that's all that important on an home built anyway.

Tony

[oilsardine[_2_]]

the modern 'VW engine': http://www.ulpower.com/

"John" > schrieb im Newsbeitrag
...
> Charles Vincent wrote:
>> RST Engineering wrote:
>>> I could be very, very wrong, but my understanding of efficiency is that
>>> 25% efficiency means that a quarter of the energy goes to torque and 3/4
>>> to heat. That would mean you throw away THREE horsepower's-worth
>>> instead of four, no?
>>>
>>> Jim
>>>
>>>
>>>
>>>> since such engines are no more than 25% efficient when it comes to
>>>> converting the heat of combustion into torque at the crankshaft. That
>>>> means that for every horsepower measured at the crank you must
>>>> generate at least four horsepower's-worth of heat in combustion.
>>>
>>>
>> You are correct, but that is also exactly what he said ---. i.e. generate
>> four hp in heat, only one available at the shaft.
>>
>> Charles
>
>
> Well that's better than a 100 watt electric light bulb, which is a 90 watt
> heater and 10 watt light source...
>
> John

[[email protected]]

On Feb 6, 1:28 am, "oilsardine" > wrote:
> the modern 'VW engine':http://www.ulpower.com/
> -------------------------------------------------------------------------------

Nice.

It's a real shame that the typical VW 'expert' knows so little about
engines :-) The ulpower people have gone out of their way to provide
easily understood explanations of how to measure torque; of torque vs
power, of Specific Fuel Consumption and so forth.

Indeed, these things are so simple -- and so fundamental to engines --
that it is difficult to understand why the EAA does NOT endorse a
program of publicly testing engines at its annual convention. The
'Experimental - Amateur-built' license is supposed to foster EDUCATION
and there are few things more educational than allowing the public to
see such demonstrations with their own eyes.

-R.S.Hoover
-EAA 58400 (Life Member)

[Charles Vincent]

cavalamb himself wrote:
> oilsardine wrote:
>
>> the modern 'VW engine': http://www.ulpower.com/
>
>
> Now that is a sweet little motor!
>
> 165 pounds
> 2600 cc
> claims 81 HP at 2800 RPM
> 500 hour TBO
> FADEC
> No Carb Ice problems
>
> Only problem - I didn't catch the price?

Isn't it more aptly a modern Continental C-85? I think the "modern VW"
as far as homebuilts go is one of the subaru's.

Charles

[Bill Daniels]

"Anthony W" > wrote in message
news:Bldqj.4239$f73.3718@trndny08...
> Bill Daniels wrote:
>
>> Well, I'm not going to build a Hyabusa flat 8 but if I were, I'd be
>> thinking about a planetary gear PSRU. Planetarys have a lot of gear
>> tooth engagement and are happy with high RPM sun gears. A fairly small
>> planetary can get 4:1 reduction which would reduce 9000RPM to a very
>> usable 2250.
>>
>> The propeller thrust bearings would be on the ring gear - the engine
>> crankshaft would see only torque loads. This little screamer would
>> produce about 280HP in stock trim from an engine about the size of an
>> O-200.
>>
>> Bill D
>
> I think we would be back to the same problem, the engine can't dissipate
> that much heat. Motorcycles don't run at peak output any more than car
> engines do and the sustainable power level would be considerably lower.
> Not that a Suzuki V8 wouldn't be fun, I don't think it has what it takes
> to be a good aircraft engine.
>
> The more I think about it, the less I think any auto engine conversion is
> going to do the job well. I'm looking for an old but rebuildable airplane
> engine that I can rebuild rather than spend all my money on an engine I
> can't trust. I don't mind it not having the certificate and I don't think
> that's all that important on an home built anyway.
>
> Tony

These are liquid cooled engines so with a large enough radiator, you could
keep it cool. I think motorcycles do run at higher percentage power than
automobiles - they have a far worse Cd.

Bill Daniels

[Charles Vincent]

cavalamb himself wrote:
> oilsardine wrote:
>
>> the modern 'VW engine': http://www.ulpower.com/
>
>
> Now that is a sweet little motor!
>
> 165 pounds
> 2600 cc
> claims 81 HP at 2800 RPM
> 500 hour TBO
> FADEC
> No Carb Ice problems
>
> Only problem - I didn't catch the price?

About nineteen grand, plus shipping, handling and any taxes.

Charles

[jan olieslagers[_2_]]

cavalamb himself schreef:
> oilsardine wrote:
>
>> the modern 'VW engine': http://www.ulpower.com/
>
>
> Now that is a sweet little motor!

looks good indeed, strange to find such a nice
offer from my own country without ever
hearing about it otherwise...

> Only problem - I didn't catch the price?

well, you could check out
http://www.ulpower.com/price.htm
where I read 12400 euro's, ex VAT of course,
but including more accesories than most

That being said, I am intrigued by your
mention of a 500 hrs TBO. Still on their own
website, I read
<quote>
ULPower has decided not to publish a TBO for our UL260i engine until we
have gained sufficient insight into how a significant number of our
engines are actually holding up to operating in real flying conditions.
</quote>

which sounds wise to this beginner's ears

[RST Engineering]

Come on, Bob. How do you expect the EAA to make a buck out of something as
useful as this? Sheesh, man, cherchez le dinero.

Jim


>
> Indeed, these things are so simple -- and so fundamental to engines --
> that it is difficult to understand why the EAA does NOT endorse a
> program of publicly testing engines at its annual convention.

[[email protected]]

On Feb 6, 8:04 am, "RST Engineering" > wrote:
> Come on, Bob. How do you expect the EAA to make a buck out of something as
> useful as this? Sheesh, man, cherchez le dinero.
> ------------------------------------------------------------------------------------------

Big Smiley :-)

The real question is what happens to all those bucks? Add up the
Total Compensation Package for all those wunnerful folks running the
EAA and it's enough to make Warren G. Buffett heave a sigh of envy.

But you're right. Valid, useful information doesn't buy full-page
ads. And of course, it IS all about money. On the other hand, the
more emphasis placed on selling a dime's worth of info for a dollar,
the quicker the demise of grass-roots aviation.

-R.S.Hoover

[Anthony W]

Bill Daniels wrote:

> These are liquid cooled engines so with a large enough radiator, you could
> keep it cool. I think motorcycles do run at higher percentage power than
> automobiles - they have a far worse Cd.
>
> Bill Daniels

The cooling systems on motorcycle engines do not have sufficient coolant
flow to keep the head from over heating under prolonged running at 3/4
to full output. The water craft and snowmobile engines may have better
flow but these also have access to lower temp coolant.

Honda makes a personal water craft that has a hot little 4 banger engine
that I thought might do the job. It would take some testing to see what
it's sustained power level would be.

Tony

[Anthony W]

cavalamb himself wrote:

> There was a Neiuport 12 project (two seater) published in Kit Planes a
> few years ago. He used a Yamaha engine and transmission - locked in
> second gear. (IIRC!)
>
> Real nice article about the airplane and engine.
>
> But no a mumblin' word about how the gearbox cratered a few hours into
> the test period.
>
> But, for Pete Sakes! Run a bike at 80% power continuously - in second
> gear(!) - what do you expect is going to happen?
>
> TANFL...

I remember seeing that article. Considering the engine they used and
how they mounted it, I'm surprised the engine didn't seize up first.
They used a Yamaha Virago V-twin mounted backwards so the shaft drive
would be pointed forward. I can think of several reasons why this setup
would fail...

A few year ago when I first thought of merging 2 of my passions (bikes
and flying) I was working on ways of turning a Virago engine sideways
like a Moto Guzzi engine. The only workable solution would have been a
custom machined side case to take power directly off the clutch basket.
This would give leave you with the built in gear reduction of the
primary drive but leave out the transmission. There are lot of things
to be concerned about in a conversion like this but the 2 biggest things
I think are; would the case hold up to the side loads and would the
vibrations of the prop over load the dampening in the clutch basket? I
think turning the engine sideways in the air stream would improve
cooling so at least that would be a plus in it's favor.

If I had enough money to work the problems out of this type of
conversion I could afford a new Rotax 4.

Tony

[Gig 601XL Builder[_2_]]

wrote:
> On Feb 6, 8:04 am, "RST Engineering" > wrote:
>> Come on, Bob. How do you expect the EAA to make a buck out of something as
>> useful as this? Sheesh, man, cherchez le dinero.
>> ------------------------------------------------------------------------------------------
>
> Big Smiley :-)
>
> The real question is what happens to all those bucks? Add up the
> Total Compensation Package for all those wunnerful folks running the
> EAA and it's enough to make Warren G. Buffett heave a sigh of envy.
>
> But you're right. Valid, useful information doesn't buy full-page
> ads. And of course, it IS all about money. On the other hand, the
> more emphasis placed on selling a dime's worth of info for a dollar,
> the quicker the demise of grass-roots aviation.
>
> -R.S.Hoover

So the obvious answer is to take the advertising out of it. What we need
to do is lobby Aviation Consumer to have an annual homebuilt issue.

[cavalamb himself[_2_]]

oilsardine wrote:

> the modern 'VW engine': http://www.ulpower.com/


Now that is a sweet little motor!

165 pounds
2600 cc
claims 81 HP at 2800 RPM
500 hour TBO
FADEC
No Carb Ice problems

Only problem - I didn't catch the price?

[Gig 601XL Builder[_2_]]

Gig 601XL Builder wrote:
> wrote:
>> On Feb 6, 8:04 am, "RST Engineering" > wrote:
>>> Come on, Bob. How do you expect the EAA to make a buck out of
>>> something as
>>> useful as this? Sheesh, man, cherchez le dinero.
>>> ------------------------------------------------------------------------------------------
>>>
>>
>> Big Smiley :-)
>>
>> The real question is what happens to all those bucks? Add up the
>> Total Compensation Package for all those wunnerful folks running the
>> EAA and it's enough to make Warren G. Buffett heave a sigh of envy.
>>
>> But you're right. Valid, useful information doesn't buy full-page
>> ads. And of course, it IS all about money. On the other hand, the
>> more emphasis placed on selling a dime's worth of info for a dollar,
>> the quicker the demise of grass-roots aviation.
>>
>> -R.S.Hoover
>
> So the obvious answer is to take the advertising out of it. What we need
> to do is lobby Aviation Consumer to have an annual homebuilt issue.


To get that idea rolling I just sent a letter to the editor. Here's a
link so others can do the same and a copy of my letter.

Dear Sirs,

I have been a subscriber for a few years now and have been very happy
with the unbiased reviews and information you provide.

I am currently building home-built aircraft and sadly the same kind of
reporting isn't currently available for experimental specific kits,
equipment or engines.

It would be great and I think you would see a fairly large audience if
you were to produce either an annual experimental issue or add a monthly
section on experimental aircraft.


http://www.aviationconsumer.com/cgi-bin/udt/fdc.collector?client_id=aviationconsumer&form_id=maileditform&link_id=3

[cavalamb himself[_2_]]

Bill Daniels wrote:
>>
>>I think we would be back to the same problem, the engine can't dissipate
>>that much heat. Motorcycles don't run at peak output any more than car
>>engines do and the sustainable power level would be considerably lower.
>>Not that a Suzuki V8 wouldn't be fun, I don't think it has what it takes
>>to be a good aircraft engine.
>>
>>The more I think about it, the less I think any auto engine conversion is
>>going to do the job well. I'm looking for an old but rebuildable airplane
>>engine that I can rebuild rather than spend all my money on an engine I
>>can't trust. I don't mind it not having the certificate and I don't think
>>that's all that important on an home built anyway.
>>
>>Tony
>
>
> These are liquid cooled engines so with a large enough radiator, you could
> keep it cool. I think motorcycles do run at higher percentage power than
> automobiles - they have a far worse Cd.
>
> Bill Daniels
>
>

There was a Neiuport 12 project (two seater) published in Kit Planes a
few years ago. He used a Yamaha engine and transmission - locked in
second gear. (IIRC!)

Real nice article about the airplane and engine.

But no a mumblin' word about how the gearbox cratered a few hours into
the test period.

But, for Pete Sakes! Run a bike at 80% power continuously - in second
gear(!) - what do you expect is going to happen?

TANFL...

[cavalamb himself[_2_]]

jan olieslagers wrote:

> cavalamb himself schreef:
>
>> oilsardine wrote:
>>
>>> the modern 'VW engine': http://www.ulpower.com/
>>
>>
>>
>> Now that is a sweet little motor!
>
>
> looks good indeed, strange to find such a nice
> offer from my own country without ever
> hearing about it otherwise...
>
>> Only problem - I didn't catch the price?
>
>
> well, you could check out
> http://www.ulpower.com/price.htm
> where I read 12400 euro's, ex VAT of course,
> but including more accesories than most
>
> That being said, I am intrigued by your
> mention of a 500 hrs TBO. Still on their own
> website, I read
> <quote>
> ULPower has decided not to publish a TBO for our UL260i engine until we
> have gained sufficient insight into how a significant number of our
> engines are actually holding up to operating in real flying conditions.
> </quote>
>
> which sounds wise to this beginner's ears

In their download section - the Maintenance Manual.PDF file -
under "Time Limits".

500 Hrs or 8 years.
whichever comes first...

[cavalamb himself[_2_]]

Charles Vincent wrote:

> cavalamb himself wrote:
>
>> oilsardine wrote:
>>
>>> the modern 'VW engine': http://www.ulpower.com/
>>
>>
>>
>> Now that is a sweet little motor!
>>
>> 165 pounds
>> 2600 cc
>> claims 81 HP at 2800 RPM
>> 500 hour TBO
>> FADEC
>> No Carb Ice problems
>>
>> Only problem - I didn't catch the price?
>
>
> Isn't it more aptly a modern Continental C-85? I think the "modern VW"
> as far as homebuilts go is one of the subaru's.
>
> Charles


A lot of people seem to think that about the Suburu, but they weight
quite a bit more than you'd think.

The extra weight means a PSRU is really mandatory to get reasonable
propeller output (HP/LB) - with all the attendent complexity, harmonic,
and weight issues.

In my mind that takes them out of the "modern VW" class.

They seem to be more at home on the nose of RV/Tailwind class airplanes.

Richard

[cavalamb himself[_2_]]

RST Engineering wrote:

> Come on, Bob. How do you expect the EAA to make a buck out of something as
> useful as this? Sheesh, man, cherchez le dinero.
>
> Jim
>
>
>
>>Indeed, these things are so simple -- and so fundamental to engines --
>>that it is difficult to understand why the EAA does NOT endorse a
>>program of publicly testing engines at its annual convention.
>
>
>

Endorsement would equate to liability.

BEsides, EAA has never really been about the reality of it - they
sell the dream.

Richard

[Peter Dohm]

"cavalamb himself" > wrote in message
...
> Charles Vincent wrote:
>
>> cavalamb himself wrote:
>>
>>> oilsardine wrote:
>>>
>>>> the modern 'VW engine': http://www.ulpower.com/
>>>
>>>
>>>
>>> Now that is a sweet little motor!
>>>
>>> 165 pounds
>>> 2600 cc
>>> claims 81 HP at 2800 RPM
>>> 500 hour TBO
>>> FADEC
>>> No Carb Ice problems
>>>
>>> Only problem - I didn't catch the price?
>>
>>
>> Isn't it more aptly a modern Continental C-85? I think the "modern VW"
>> as far as homebuilts go is one of the subaru's.
>>
>> Charles
>
>
> A lot of people seem to think that about the Suburu, but they weight
> quite a bit more than you'd think.
>
> The extra weight means a PSRU is really mandatory to get reasonable
> propeller output (HP/LB) - with all the attendent complexity, harmonic,
> and weight issues.
>
> In my mind that takes them out of the "modern VW" class.
>
> They seem to be more at home on the nose of RV/Tailwind class airplanes.
>
> Richard

A lot of good points, and the radiator plumbing also seems to provide many
happy hours of tinkering for a lot of folks.

Actually, some of the small inline engines, such as those from the Geo/Chevy
Metro, have shown some promise--which was unfortunately mixed with far too
much hype. Actually, it the basic weight is anywhere near as light as was
claimed, then a realistic power rating should work quite well.

Regrettably, I have had no opportunity to weigh any of the engines in
question.

Peter

[Blueskies]

"Peter Dohm" > wrote in message .. .

> A lot of good points, and the radiator plumbing also seems to provide many happy hours of tinkering for a lot of
> folks.
>
> Actually, some of the small inline engines, such as those from the Geo/Chevy Metro, have shown some promise--which was
> unfortunately mixed with far too much hype. Actually, it the basic weight is anywhere near as light as was claimed,
> then a realistic power rating should work quite well.
>
> Regrettably, I have had no opportunity to weigh any of the engines in question.
>
> Peter
>
>
>

One of our neighbors is flying a Geo Metro engine in his RagWing Special. Great sound and he loves it, very reliable (so
far!) and simple key start...

[Peter Dohm]

"Ernest Christley" > wrote in message
...
> cavalamb himself wrote:
>
>> There was a Neiuport 12 project (two seater) published in Kit Planes a
>> few years ago. He used a Yamaha engine and transmission - locked in
>> second gear. (IIRC!)
>>
>> Real nice article about the airplane and engine.
>>
>> But no a mumblin' word about how the gearbox cratered a few hours into
>> the test period.
>>
>> But, for Pete Sakes! Run a bike at 80% power continuously - in second
>> gear(!) - what do you expect is going to happen?
>>
>> TANFL...
>
> George Graham ran a rotary conversion with the stock rotary manual
> transmission as a PSRU. It lasted a couple hundred hours before
> disintegrating (if I remember correctly).
>
> --
Actually, that makes a lot of sense. Reduction gear problems were explained
to me, there are essentially two causes of uneven wear in a spur gear
transmission; both of which lead to failure. The worse of the two occurs if
the gear ratio allows some the teeth on each gear to transmit power more
frequently than the others--a classic example would be a propeller shaft
turning exactly half the speed of the crank shaft. The slower cause of
uneven wear would occur whenever the driving gear is permanently oriented in
the same relation to the crankshaft so that the same quadrants of the gear
always transmit the power pulses--a condition that is normally avoided by
the clutch, and can presumably be resolved by the installation of a
centrifugal clutch.

I don't personally know how the problem is usually solved in purpose built
PSRU's and the only possibility that I find obvious is that the driving gear
might be harder than the driven gear. That might slow the process, but the
PSRU would still be a major component in calculating the TBO. Perhaps some
here have experience in this area.

Peter

[[email protected]]

On Feb 6, 8:03 am, Charles Vincent > wrote:
>
> Isn't it more aptly a modern Continental C-85? I think the "modern VW"
> as far as homebuilts go is one of the subaru's.
>
> Charles

They're not the big solution, either. I installed a Subaru 2.2
litre on a Glastar, using an RAF redrive. The problems I encountered:
-Some vibration at around 1400 engine RPM. Caused by the very light
RAF aluminum flywheel, which doesn't absorb all that much pulsation,
and this interacts with the prop's mass, which has a different
resonance. We had initially used an Ivoprop, and could not balance it
chordwise because the blades would shift a little on the hub bolts.
The subsequent Warp Drive prop was better, but had much narrower chord
and did not pull as well as the Ivo. Further, the Ivo's blades would
flutter if there was too little tension on the torque rods. Scary.

-Burned valves. The engine had a converted Holley two-barrel, with
mixture control that was way too sensitive, to the point that it
either ran or didn't. I modified the valve to get some range. On a
short-field takeoff, usual SOP with an aircraft engine is to lean to
max RPM with the brakes locked and throttle wide open; do that with
the Soob and the valves will burn real quick. The engine has four
valves per cylinder and they're about the size of the valves in a
Briggs and Stratton lawnmower engine. Tiny, with little skinny stems.
Compare them to a Lyc's valves. The 16-valve Soob was designed for
computerized fuel injection, for good reason.

-Couldn't install a mechanical fuel pump in it. No place for one. So,
since you can't rely on gravity feed (the Holley has a small float
valve designed for a 4 to 7 psi fuel pressure) you need an electric
pump. Two of them, just in case. And the ignition is run off the
aircraft's fuel system. So, since (as anyone with car or airplane
mechanical experience knows) 90% of all engine problems are
electrical, it's asking for trouble. Real quiet trouble. Avoiding that
requires another battery and a big diode to protect it, more weight
and complexity and cost and room that isn't there.

-The engine was rated at 130 hp at 5600 RPM. The Glastar was designed
for engines from 125 to 180 hp. Should be good enough, right? It was
OK for takeoff and climb, but for cruise it was lousy. A Lycoming,
redlined at 2700 RPM, is easily cruised at 2500 or even 2600. The
engine is rated for 2700 continuous, if you want that. The Subaru, if
you try to cruise it at an equivalent RPM of, say, 5300 or 5400, will
wear out in no time flat and will burn phenomenal amounts of fuel,
too. And makes the most awesome cabin noise. So you end up cruising at
4700 max, which gives an anemic cruise of 110 mph instead of the 135
that the Lyc 125 would give you. Both engines will give the claimed
143 mph at full RPM, so it's not a propeller pitch issue.

-The exhaust system was two tiny mufflers that did little to contain
the noise. There's no room under the heads, inside the cowl, since the
engine sits low to get the thrust line up where it belongs. I could
hear this airplane 7 miles away. When I flew it, I stayed away from
town.

-The engine compartment was very tight, once the radiator and its
associated baffling was put in. The cooling system was the one thing I
built that worked really well. The cabin heater was the Subaru's
heater core.

-The ultimate cost, in terms of the stupidly complicated engine mount
I had to build and have professionally tigged (17 pieces of tubing and
four special engine brackets), the time I spent, the constant
tinkering, the cowling modifications necessary to make it fit, and the
ultimately much lower resale value it had (half or less than a Lyc-
powered Glastar), it just wasn't worth it.

Dan

[cavalamb himself[_2_]]

wrote:
>
> -The ultimate cost, in terms of the stupidly complicated engine mount
> I had to build and have professionally tigged (17 pieces of tubing and
> four special engine brackets), the time I spent, the constant
> tinkering, the cowling modifications necessary to make it fit, and the
> ultimately much lower resale value it had (half or less than a Lyc-
> powered Glastar), it just wasn't worth it.
>
> Dan


Dan! You are not going to sell magazines that way...

[[email protected]]

On Feb 7, 3:42 pm, cavalamb himself > wrote:

> Dan! You are not going to sell magazines that way...

Good thing I don't rely on magazine sales, huh?

Funny, though. People are always asking me for my opinions on
mechanical stuff. Sometimes they don't like the answers. Sometimes
they want to buy an airplane, so I tell them what to look for and be
aware of and be scared of and that the pretty airplane can clean out
your bank account real fast. They don't like that because they want
that airplane so bad. They buy it and find out I was right. Usually.
I'm supposed to be working on my Hummelbird. That's why I
asked Veeduber about the 1/2 VW, and he says they aren't so good. I
believe that, and have to take it into account. Maybe, if I don't fly
much, it'll be good enough, as long as I expect to be doing the valves
every 50 hours or so. I have been warned, see. I 'm considering
sticking the whole four-cylinder VW on it, like Bruce King did; a
weight penalty, but a little less work expected from each jug.
Sometimes we don't like the opinions of others. We need to
evaluate the source, and if it's experienced in the matter at hand, we
should shut up and listen.
Even if it hurts magazine sales.

Dan

[Stuart & Kathryn Fields]

> wrote in message
...
> On Feb 7, 3:42 pm, cavalamb himself > wrote:
>
>> Dan! You are not going to sell magazines that way...
>
> Good thing I don't rely on magazine sales, huh?
>
> Funny, though. People are always asking me for my opinions on
> mechanical stuff. Sometimes they don't like the answers. Sometimes
> they want to buy an airplane, so I tell them what to look for and be
> aware of and be scared of and that the pretty airplane can clean out
> your bank account real fast. They don't like that because they want
> that airplane so bad. They buy it and find out I was right. Usually.
> I'm supposed to be working on my Hummelbird. That's why I
> asked Veeduber about the 1/2 VW, and he says they aren't so good. I
> believe that, and have to take it into account. Maybe, if I don't fly
> much, it'll be good enough, as long as I expect to be doing the valves
> every 50 hours or so. I have been warned, see. I 'm considering
> sticking the whole four-cylinder VW on it, like Bruce King did; a
> weight penalty, but a little less work expected from each jug.
> Sometimes we don't like the opinions of others. We need to
> evaluate the source, and if it's experienced in the matter at hand, we
> should shut up and listen.
> Even if it hurts magazine sales.
>
> Dan

Dan: Totally agree. Being the Publisher of Experimental Helo magazine I
had to address the problem of publishing ethics vs money. Ethics won out.

Stu

[Morgans[_2_]]

> wrote

> On a
> short-field takeoff, usual SOP with an aircraft engine is to lean to
> max RPM with the brakes locked and throttle wide open; do that with
> the Soob and the valves will burn real quick.

But it isn't normal procedure for an aircraft engine on a normal take-off.
Full rich, unless you are at a pretty high field.

Recognizing that the valves can burn, what's the problem with giving it
enough fuel too keep the temperatures down? If that means you have to set
your minimum field length a little longer, then so be it.

I'm not defending the soob, but it is wise to recognize the shortcomings of
what ever engine you brung, and run it accordingly. You would be hard
pressed to find _any_ engine that does not have weaknesses.
--
Jim in NC

[Anthony W]

Until the Franklin parts info post, I thought Franklin was dead and
gone. It seems to me that their air cooled 4 banger has a lot to offer
and right now they have it on special for $6900 but the regular prices
isn't listed.

Anybody know if these new Franklin engines are any good? If they are, a
complete engine for under $7 make me wonder why anybody would use a VW
engine instead of one of these...

http://www.franklinengines.com/

Tony

[Morgans[_2_]]

"Anthony W" > wrote

> Anybody know if these new Franklin engines are any good? If they are, a
> complete engine for under $7 make me wonder why anybody would use a VW
> engine instead of one of these...

I have no first hand experience, but I know someone with one, and they
don't have kind things to say, as compared to the other "big two" opposed
engine makers. I don't know of anything specific, though.
--
Jim in NC

[Stuart & Kathryn Fields]

Limited experience with a Franklin in a Bell 47 had a lot of lead fouling,
compared with Lycoming engine experience. Different plugs or mags? Also if
there wasn't oil under it before start up, it needed more oil. Not my bird
though. All of the above could be maintenance related?

Stu
"Morgans" > wrote in message
...
>
> "Anthony W" > wrote
>
>> Anybody know if these new Franklin engines are any good? If they are, a
>> complete engine for under $7 make me wonder why anybody would use a VW
>> engine instead of one of these...
>
> I have no first hand experience, but I know someone with one, and they
> don't have kind things to say, as compared to the other "big two" opposed
> engine makers. I don't know of anything specific, though.
> --
> Jim in NC
>

[Morgans[_2_]]

"Stuart & Kathryn Fields" > wrote in message
.. .
> Limited experience with a Franklin in a Bell 47 had a lot of lead fouling,
> compared with Lycoming engine experience. Different plugs or mags? Also
> if there wasn't oil under it before start up, it needed more oil. Not my
> bird though. All of the above could be maintenance related?

I do seem to recall the fact that it leaked a lot of oil.

Also, it seemed to have top problems, with cylinder problems being common.

Again, I want to stress, don't take my word on this; it isn't first hand,
and there is not a lot to go on.

I would think if some digging was done, a person could come up with some
common complaints.
--
Jim in NC

[[email protected]]

On Feb 8, 2:18 pm, "Morgans" > wrote:
> Recognizing that the valves can burn, what's the problem with giving it
> enough fuel too keep the temperatures down? If that means you have to set
> your minimum field length a little longer, then so be it.
>
> I'm not defending the soob, but it is wise to recognize the shortcomings of
> what ever engine you brung, and run it accordingly. You would be hard
> pressed to find _any_ engine that does not have weaknesses.

But it involved learning the hard way: A burnt valve
immediately after takeoff, with the associated shudder and power loss.
Could have been a bad scene. Nobody had told me about the sensitivity
of those valves, and I didn't realize why they had burned so easily
until I took the head off and had the valves out. They are really
slender.
Point was: After all the fooling around and the unexpected
costs associated with the installation, it wasn' worth it. These
things tend to cost way more than we figure, and take a long time to
sort out. I just want others to know that, so that they aren't as
unpleasantly surprised like we were.

Dan

[Morgans[_2_]]

> wrote

> Point was: After all the fooling around and the unexpected
> costs associated with the installation, it wasn' worth it. These
> things tend to cost way more than we figure, and take a long time to
> sort out. I just want others to know that, so that they aren't as
> unpleasantly surprised like we were.

Point taken.

Auto engine installations are definitely for the person that wants something
different, and realizes that there will most likely be some things to sort
out.
--
Jim in NC

[jerry wass]

Stuart & Kathryn Fields wrote:
> Limited experience with a Franklin in a Bell 47 had a lot of lead fouling,
> compared with Lycoming engine experience. Different plugs or mags? Also if
> there wasn't oil under it before start up, it needed more oil. Not my bird
> though. All of the above could be maintenance related?
>
> Stu
> "Morgans" > wrote in message
> ...
>> "Anthony W" > wrote
>>
>>> Anybody know if these new Franklin engines are any good? If they are, a
>>> complete engine for under $7 make me wonder why anybody would use a VW
>>> engine instead of one of these...
>> I have no first hand experience, but I know someone with one, and they
>> don't have kind things to say, as compared to the other "big two" opposed
>> engine makers. I don't know of anything specific, though.
>> --
>> Jim in NC
>>
>
>
The Franks use a 14mm plug in lieu of the usual 18mm--there's not as
much room between electrodes & porcelain to let the lead balls fall out.
especially the 3 electrode plug which works a lot better than the other
types. Jerry

[Anthony W]

Jerry Wass wrote:
> The Franks use a 14mm plug in lieu of the usual 18mm--there's not as
> much room between electrodes & porcelain to let the lead balls fall out.
> especially the 3 electrode plug which works a lot better than the other
> types. Jerry

According to the website the new Franklin engines have 18mm spark plugs.
I can only assume they discovered that problem.

What I don't understand is how the Franklin engine company ended up in
Eastern Europe. The last I'd heard of them was that the Franklin engine
division was the only surviving department of Tucker motors. From what
I read Tucker brought Franklin because they couldn't get the bugs out of
their own engine design.

Tony

[jan olieslagers[_2_]]

cavalamb himself schreef:
> oilsardine wrote:
>
>> the modern 'VW engine': http://www.ulpower.com/
>
>

I wonder if this could some follow-up to the engine developed for the
Masquito helicopter (see http://home.comcast.net/~aeroengine/Masquito.html)
If so, it is really a Jabiru descendant rather than VW.

[Blueskies]

"Jerry Wass" > wrote in message . net...
> Stuart & Kathryn Fields wrote:
>> Limited experience with a Franklin in a Bell 47 had a lot of lead fouling,
>> compared with Lycoming engine experience. Different plugs or mags? Also if
>> there wasn't oil under it before start up, it needed more oil. Not my bird
>> though. All of the above could be maintenance related?
>>
>> Stu
>> "Morgans" > wrote in message
>> ...
>>> "Anthony W" > wrote
>>>
>>>> Anybody know if these new Franklin engines are any good? If they are, a
>>>> complete engine for under $7 make me wonder why anybody would use a VW
>>>> engine instead of one of these...
>>> I have no first hand experience, but I know someone with one, and they
>>> don't have kind things to say, as compared to the other "big two" opposed
>>> engine makers. I don't know of anything specific, though.
>>> --
>>> Jim in NC
>>>
>>
>>
> The Franks use a 14mm plug in lieu of the usual 18mm--there's not as
> much room between electrodes & porcelain to let the lead balls fall out.
> especially the 3 electrode plug which works a lot better than the other
> types. Jerry



Plus, they still spec 100/130 for the minimum fuel grade?
http://www.franklinengines.com/4a.cfm
http://www.franklinengines.com/6a.cfm

If they meant 100LL, why wouldn't they say it?

The TCDS that I can find at FAA.GOV list minimum octane at 73 to 80 for the older engines...

[John[_14_]]

Anthony W wrote:
> Jerry Wass wrote:
>> The Franks use a 14mm plug in lieu of the usual 18mm--there's not as
>> much room between electrodes & porcelain to let the lead balls fall out.
>> especially the 3 electrode plug which works a lot better than the
>> other types. Jerry
>
> According to the website the new Franklin engines have 18mm spark plugs.
> I can only assume they discovered that problem.
>
> What I don't understand is how the Franklin engine company ended up in
> Eastern Europe. The last I'd heard of them was that the Franklin engine
> division was the only surviving department of Tucker motors. From what
> I read Tucker brought Franklin because they couldn't get the bugs out of
> their own engine design.
>
> Tony

The Polish company PZL bought the Franklin production rights, tooling,
engineering etc from whatever receiver was sitting on it back in the 90s.

Wasn't aware that Tucker ever owned Franklin. He originally got his
Franklin engines from Howard Hughes, who had a warehouse full of VIO 5
something engines for helicopters and wanted to unload them on a sucker,
and found a willing dupe only one letter of the alphabet away.

John

[Anthony W]

Blueskies wrote:

>>>>> Anybody know if these new Franklin engines are any good?
>> The Franks use a 14mm plug in lieu of the usual 18mm--there's not as
>> much room between electrodes & porcelain to let the lead balls fall out.
>> especially the 3 electrode plug which works a lot better than the
>> other types. Jerry
>
>
>
> Plus, they still spec 100/130 for the minimum fuel grade?
> http://www.franklinengines.com/4a.cfm
> http://www.franklinengines.com/6a.cfm
>
> If they meant 100LL, why wouldn't they say it?
>
> The TCDS that I can find at FAA.GOV list minimum octane at 73 to 80 for
> the older engines...

I was wondering about that too. The compression ratio doesn't seem high
enough to require that. Perhaps a thicker head gasket could be used to
lower the CR so it would run on auto-premium to make it cheaper to operate.

Tony

[Anthony W]

John wrote:

> The Polish company PZL bought the Franklin production rights, tooling,
> engineering etc from whatever receiver was sitting on it back in the 90s.
>
> Wasn't aware that Tucker ever owned Franklin. He originally got his
> Franklin engines from Howard Hughes, who had a warehouse full of VIO 5
> something engines for helicopters and wanted to unload them on a sucker,
> and found a willing dupe only one letter of the alphabet away.
>
> John

I didn't verify it but according to a History channel show on Tucker.
After too many failures of the Tucker engine, Franklin aircraft engines
were converted to liquid cooling and proved to be reliable and Tucker
bought the Franklin company to be sure and have an uninterrupted supply
of engines for his cars. After the bankruptcy, the Franklin engine
company was sold off but I don't know who bought it and I assumed they
were gone forever. If the Pols are doing a good job at building these
new Franklin engines, they sure look like a bargain.

Tony

[stol]

On Feb 8, 7:01*pm, "Morgans" > wrote:
> > wrote
>
> > * * * Point was: *After all the fooling around and the unexpected
> > costs associated with the installation, it wasn' worth it. These
> > things tend to cost way more than we figure, and take a long time to
> > sort out. I just want others to know that, so that they aren't as
> > unpleasantly surprised like we were.
>
> Point taken.
>
> Auto engine installations are definitely for the person that wants something
> different, and realizes that there will most likely be some things to sort
> out.
> --
> Jim in NC

That's the "educational" part of homebuilt experimental planes....

Ben
www.haaspowerair.com

[Peter Dohm]

"stol" > wrote in message
...
On Feb 8, 7:01 pm, "Morgans" > wrote:
> > wrote
>
> > Point was: After all the fooling around and the unexpected
> > costs associated with the installation, it wasn' worth it. These
> > things tend to cost way more than we figure, and take a long time to
> > sort out. I just want others to know that, so that they aren't as
> > unpleasantly surprised like we were.
>
> Point taken.
>
> Auto engine installations are definitely for the person that wants
> something
> different, and realizes that there will most likely be some things to sort
> out.
> --
> Jim in NC

That's the "educational" part of homebuilt experimental planes....

Ben
www.haaspowerair.com

----------------above line is prior post (OE strikes again!)--------------

I've seen a few really nice ones, and a couple that got a little too
educational!

Peter

[Steve Hix]

In article <hNorj.881$R64.37@trndny03>,
Anthony W > wrote:
>
> I didn't verify it but according to a History channel show on Tucker.
> After too many failures of the Tucker engine, Franklin aircraft engines
> were converted to liquid cooling and proved to be reliable and Tucker
> bought the Franklin company to be sure and have an uninterrupted supply
> of engines for his cars. After the bankruptcy, the Franklin engine
> company was sold off but I don't know who bought it and I assumed they
> were gone forever.

At least as of the mid-70s Franklin engines were in production.

About the time I first started instruction, Bellanca was making
Aeroncas, and they offered their 7AC equivalent with a 2-cylinder
Franklin engine.

For $4995 FAF. (I wanted one *sooooooooooo* much at the time.)

> If the Pols are doing a good job at building these
> new Franklin engines, they sure look like a bargain.
>
> Tony

[[email protected]]

On Feb 9, 2:10 pm, Anthony W > wrote:
> I was wondering about that too. The compression ratio doesn't seem high
> enough to require that. Perhaps a thicker head gasket could be used to
> lower the CR so it would run on auto-premium to make it cheaper to operate.


I've had very little to do with Franklins, but if they're built
like most other opposed aircraft engines, there is no head gasket. The
steel cylinder screws into the aluminum head, more or less
permanently, using a shrink fit. The only way to lower the compression
ratio in such engines is to shim the cylinder base/crankcase
junction.
I once owned a McCulloch two-stroke four-cylinder drone
engine that had been modified this way to derate it from 72 hp to 50
and to allow it to run smoother at a lower RPM. Terrible engine,
commonly used years ago in Bensen's gyrocopters. They'd been built by
McCulloch for the military, who used them in target drones for anti-
aircraft gunners to practice shooting down, so the engine was designed
for a 15-minute service life or something like that. In homebuilts,
they vibrated like mad, and the mag would get hot and quit. The
carburetor throttle shaft would wear the thin carb barrel walls out in
no time flat and leak air. But cheap they were, light, and plentiful.
Couple pictures of one, and one of a Franklin drone engine, too:
http://www.barnstormers.com/EVENTS/040619/museum/museum-21.html

Dan

[Anthony W]

wrote:

> I've had very little to do with Franklins, but if they're built
> like most other opposed aircraft engines, there is no head gasket. The
> steel cylinder screws into the aluminum head, more or less
> permanently, using a shrink fit. The only way to lower the compression
> ratio in such engines is to shim the cylinder base/crankcase
> junction.

This seems an odd way of doing things to me but my background is in
motorcycles not aviation.

> I once owned a McCulloch two-stroke four-cylinder drone
> engine that had been modified this way to derate it from 72 hp to 50
> and to allow it to run smoother at a lower RPM. Terrible engine,
> commonly used years ago in Bensen's gyrocopters. They'd been built by
> McCulloch for the military, who used them in target drones for anti-
> aircraft gunners to practice shooting down, so the engine was designed
> for a 15-minute service life or something like that. In homebuilts,
> they vibrated like mad, and the mag would get hot and quit. The
> carburetor throttle shaft would wear the thin carb barrel walls out in
> no time flat and leak air. But cheap they were, light, and plentiful.
> Couple pictures of one, and one of a Franklin drone engine, too:
> http://www.barnstormers.com/EVENTS/040619/museum/museum-21.html

My old business partner (some 25 odd years ago) had both a 2 cylinder
and 4 cylinder drone engines hanging up in the bike shop. I agree it
sure looked cheaply made. He had them for display items and I don't
think he ever ran either of them.

Tony

[cavalamb himself[_2_]]

wrote:
> On Feb 9, 2:10 pm, Anthony W > wrote:
>
>>I was wondering about that too. The compression ratio doesn't seem high
>>enough to require that. Perhaps a thicker head gasket could be used to
>>lower the CR so it would run on auto-premium to make it cheaper to operate.
>
>
>
> I've had very little to do with Franklins, but if they're built
> like most other opposed aircraft engines, there is no head gasket. The
> steel cylinder screws into the aluminum head, more or less
> permanently, using a shrink fit. The only way to lower the compression
> ratio in such engines is to shim the cylinder base/crankcase
> junction.
> I once owned a McCulloch two-stroke four-cylinder drone
> engine that had been modified this way to derate it from 72 hp to 50
> and to allow it to run smoother at a lower RPM. Terrible engine,
> commonly used years ago in Bensen's gyrocopters. They'd been built by
> McCulloch for the military, who used them in target drones for anti-
> aircraft gunners to practice shooting down, so the engine was designed
> for a 15-minute service life or something like that. In homebuilts,
> they vibrated like mad, and the mag would get hot and quit. The
> carburetor throttle shaft would wear the thin carb barrel walls out in
> no time flat and leak air. But cheap they were, light, and plentiful.
> Couple pictures of one, and one of a Franklin drone engine, too:
> http://www.barnstormers.com/EVENTS/040619/museum/museum-21.html
>
> Dan
>
>

Perhaps, like teh VW, a spacer at teh bottom of the cylinder can be
used to adjust compression?

[Fred the Red Shirt]

On Feb 10, 12:57 am, cavalamb himself > wrote:
> wrote:
> > On Feb 9, 2:10 pm, Anthony W > wrote:
>
> >>I was wondering about that too. The compression ratio doesn't seem high
> >>enough to require that. Perhaps a thicker head gasket could be used to
> >>lower the CR so it would run on auto-premium to make it cheaper to operate.
> ...
>
> > I once owned a McCulloch two-stroke four-cylinder drone
> > engine that had been modified this way to derate it from 72 hp to 50
> > and to allow it to run smoother at a lower RPM. Terrible engine,
> > commonly used years ago in Bensen's gyrocopters. They'd been built by
> > McCulloch for the military, who used them in target drones for anti-
> > aircraft gunners to practice shooting down, so the engine was designed
> > for a 15-minute service life or something like that. In homebuilts,
> > they vibrated like mad, and the mag would get hot and quit. The
> > carburetor throttle shaft would wear the thin carb barrel walls out in
> > no time flat and leak air. But cheap they were, light, and plentiful.
> > Couple pictures of one, and one of a Franklin drone engine, too:
> >http://www.barnstormers.com/EVENTS/040619/museum/museum-21.html
>
> > Dan
>
> Perhaps, like teh VW, a spacer at teh bottom of the cylinder can be
> used to adjust compression?

I know someone who added a third piston ring to his pistons.

He said he got 95 hp, didn't say for how long, and I don't think he
ever ran it full bore for very long.

--

FF

[Highflyer]

"Fred the Red Shirt" > wrote in message
...
> On Feb 10, 12:57 am, cavalamb himself > wrote:
>> wrote:
>> > On Feb 9, 2:10 pm, Anthony W > wrote:
>>
>> >>I was wondering about that too. The compression ratio doesn't seem
>> >>high
>> >>enough to require that. Perhaps a thicker head gasket could be used to
>> >>lower the CR so it would run on auto-premium to make it cheaper to
>> >>operate.
>> ...
>>
>> > I once owned a McCulloch two-stroke four-cylinder drone
>> > engine that had been modified this way to derate it from 72 hp to 50
>> > and to allow it to run smoother at a lower RPM. Terrible engine,
>> > commonly used years ago in Bensen's gyrocopters. They'd been built by
>> > McCulloch for the military, who used them in target drones for anti-
>> > aircraft gunners to practice shooting down, so the engine was designed
>> > for a 15-minute service life or something like that. In homebuilts,
>> > they vibrated like mad, and the mag would get hot and quit. The
>> > carburetor throttle shaft would wear the thin carb barrel walls out in
>> > no time flat and leak air. But cheap they were, light, and plentiful.
>> > Couple pictures of one, and one of a Franklin drone engine, too:
>> >http://www.barnstormers.com/EVENTS/040619/museum/museum-21.html
>>
>> > Dan
>>
>> Perhaps, like teh VW, a spacer at teh bottom of the cylinder can be
>> used to adjust compression?
>
> I know someone who added a third piston ring to his pistons.
>
> He said he got 95 hp, didn't say for how long, and I don't think he
> ever ran it full bore for very long.
>
> --
>
> FF

Many years ago a friend of mine built a racing sports car around a McCullogh
drone engine coupled to a VW transaxle with a flipped ring gear so the
engine could mount in front of the axle. We balanced the engine and ported
and relieved it. Changed to carb out for an old one barrel Pontiac carb and
it put out about 120 HP on a dyno at 12000 rpm. ( no valve float! ) The
resulting car turned a quarter mile at the drag strip between 10.2 and 10.4
seconds. Not bad at all for a two place automobile with 66 cubic inches of
engine!

Highflyer
2008 Pinckneyville Rec Aviation Flyin

The annual flyin time is coming around again! I finally got to where I
could find things in the hangar again, which is a sure indication that it is
time to start flyin preparations!

The local motels will be filling up fast again so you may want to get your
reservations in as soon as you can if you want a close motel room.

WHEN: May 16, 17, and 18 this year. Once again, it is the full weekend
prior to the Memorial Day official weekend. This has become the traditional
historical date for the flyin. It allows folks to plan well ahead to this
incredible trek. For many it becomes the cross country trip that they talk
about to everyone that will hold still long enough to listen.

WHERE: Pinckneyville DuQuoin Airport, Pinckneyville, Illinois. PJY is the
airport identifier. Put K in front if you have a fussy GPS. We are about
80 miles southeast of the Arch in St. Louis. There is a 4001 foot ( have to
be over 4000 feet for jets! ) north-south runway ( 18L – 36R ) with an 1800
foot grass runway parallel to the northern half.
( 18R – 36L ) . There is no taxiway. This an access taxiway perpendicular
to the runways. We do have instrument approachs again, but they are GPS
approachs only.

WHAT: The annual t here day get together of the diehards on the
rec.aviation newsgroups. Buddy rides all day and hangar flying all night.
Other entertainment as happens. Beer, soda, and good food. The PJY
barbeque is world renowned, as are the uniquely HOT Italian sausages served
on Thursday night. The Red Lady should be flying this year.

WHO: Pilots, about to be Pilots, wannabe Pilots, and anybody else who is
willing to put up with a bunch of wild eyed folks who talk about airplanes
and flying all day and all night.

COST: This is not one of those "break the bank" flyins. Highflyer and Mary
try to keep the costs in line so that we can have a good time without being
rich. We do that because a lot of people who come to the flyin own
airplanes. We all know that people who own an airplane are not rich
anymore! We try to collect $25 from everyone to defray the cost of the
beverages and the groceries. We do breakfast, lunch, and dinner every day.
Usually we have baby back ribs, steak, and chicken on Saturday night.
Friday night we have something good. No one goes hungry. We do have
something for vegetarians.

ACCOMODATIONS: Pitch a tent next to your airplane if you like. There is no
charge for camping on the field. We have a couple of bathrooms, but no
showers. Generally, if someone really would like to shower one of the folks
in a motel can help you out. We do have a garden hose. There are places
you can park a camper or motorhome near the action. If you are really nice,
we can even run you out an extension cord for an electrical hookup. No
sewer hookups though.

If you want a motel there are several in the area now. The preferred flyin
motel is the Mainstreet Inn, in Pinckneyville. The lady who runs it always
puts up with our group graciously. One year she even shortsheeted every bed
in the place, for a small bribe!
Her phone number is 618-357-2128. The rates are quite reasonable.

A little fancier is the local Oxbow Bed and Breakfast. This is between the
airport and town, right on the edge of town. A number of our folks stay
there every year they come and speak very highly of the establishment.
Their phone number is 618-357-9839.

We always manage to arrange some kind of transportation to and from both of
these places. If they are full there are other motels in the area and
transportation can usually be managed with no particular problems.

HOW: Flying to PJY is the primo way to arrive. If that doesn't work many
fly commercial to St. Louis and rent a car for the last 90 miles from the
airport. Whatever works for you works for us! Pinckneyville airport is
right on Illinois 127 just six miles south of the town of Pinckneyville.
Route 127 is exit 50 off of I-64. The airport is about 30 miles south of
I-64.

Please send an email to Mary at so that she can get some
idea how many steaks to buy for Saturday night dinner! It makes it a lot
easier when we have some idea of how many people to plan for meals.

[Bret Ludwig]

>
> in the usual VW car engine the harmonic charactersitics of the
> crankshaft are such that the destructive vibration occurs a few
> thousand revs above the max possible rpm so the engine never
> experiences a problem.
>
> in aircraft installations with large heavy propellors attached to the
> shaft the harmonic range occurs at a lower RPM.
>
> particularly with large 3 bladed ground adjustable composite props the
> destructive harmonic range comes down to about 3,200rpm. most VW's
> would run at around those revs so the problem becomes an unavoidable
> one.
>
> the destructive harmonics are indetectable in the cockpit above the
> normal engine vibrations but in the engine's interior those harmonics
> deliver hammer like blows to the crank web. the hollow area above the
> centre of the internal web gets a fair shaking and develops a fine
> hairline fatigue crack. this crack leaks copious amounts of oil and of
> course there is no way of welding oily electron so the case becomes
> junk.

It certainly should be possible to degrease the case by vapor
condensation. Tricloroethane was the solvent of choice before the
enviro-nazis got hold of things.

>
> the problem can be avoided completely by using lightweight fixed two
> bladed wooden props.

Better idea is to put a flywheel on the engine and use a redrive that
provides some isolation to the engine from its load. The marine
industry figured this out in the 1950s and the inboard/outdrive is
nearly universal now.

[Bret Ludwig]

>
> The maximum SUSTAINABLE power available from ANY air-cooled engine is
> determined by the engine's ability to cool itself -- to couple its
> waste-heat to the atmosphere. And with a carburetted, spark-ignited,
> gasoline-fueled engine there is a LOT of waste heat to be managed
> since such engines are no more than 25% efficient when it comes to
> converting the heat of combustion into torque at the crankshaft. That
> means that for every horsepower measured at the crank you must
> generate at least four horsepower's-worth of heat in combustion.
> These basic rules of thermodynamics are made even worse by two
> additional factors, the first being 'Economy of Scale' in that smaller
> engines are LESS thermally efficient than larger engines, and the
> basic definition of Standard Day conditions -- 59.9 degrees on the
> Fahrenheit scale and an atmospheric pressure of 29.92 inches of
> mercury -- a fairly cool day.
>
> With those laws of physics as preamble the next factor worthy of note
> is the physical dimensions of the Volkswagen cylinder head and the
> fact that ALL VW heads have the same exterior dimensions. This is
> because they must fit under the stock VW engine shrouding. No
> manufacturer of VW heads, either stock or after-market, offers a head
> having more fin area. Indeed, most after-market heads have LESS, due
> either to thickening of the combustion chamber wall or even
> eliminating one of the eight fins -- and in a few cases they have done
> both.

I think the Scat single unit heads have somewhat more as do the 356
Porsche heads after '59 or so. Both require different sheet metal in
the car.
>
> All -- ALL -- Volkswagen heads in common use today are derived from
> the heads developed for the 1300cc engine; their external physical
> dimensions remained exactly the same for the later 1500 and 1600
> engines. The output of the 1300 engine was approximately 40hp and
> could SUSTAIN that level of output indefinitely under Standard Day
> conditions. This engine was bored-out to 83mm to produce the 1500
> engine, then over-bored to 85.5mm to create the 1600 (actual
> displacement 1584cc), the maximum output of which was 57bhp for
> carburetted models, achieved in the 1971 model year. But that level
> of output could only be sustained for a bit less than FOUR MINUTES,
> until the cylinder head temperature exceeded safe levels, again under
> Standard Day conditions.
>
> So what's this 'safe level' of CHT? About 450 degrees on the
> Fahrenheit scale. This reflects the fact that VW heads are made of
> CAST aluminum (as opposed to a forging) and the fact aluminum is a
> 'white short' metal, meaning it becomes frangible when its temperature
> enters the 'plastic' range. A characteristic of white-short metals is
> that when heated they fracture like a cube of sugar when subjected to
> stress. The floor of the frangible range is a bit higher for a
> forging -- about 550F according to Pratt-Whitney -- but can be as low
> as 400F in a casting, depending upon the alloy.

You could always go to an iron or bronze (if TEL is eschewed)
head.....

>
> A common thread used to impress technologically naive buyers is tales
> of driving a Volkswagen bug or bus for hours on end with the throttle
> wide open. The fact the engine was was probably producing LESS THAN
> TWENTY HORSEPOWER goes unsaid. This involves the Horsepower Myth and
> generally leaves a large black question mark hanging over the heads of
> those without an engineering background but it needs to be touched
> upon since ignorance can be as deadly as a machine gun when it comes
> to aviation.
>
> The Horsepower Myth was create by James Watt in order to sell his
> modified Newcommen steam engine to mine owners. To do so he added the
> element of TIME to the power equation and from that day to this the
> general public has been comfortable with the idea that 'horsepower'
> represents a given quanta of energy... which it does... but only
> within a defined unit of TIME. And from that day to this, that
> arithmetical loophole has been used by those eager to prey upon
> technologically naive consumers.
>
> Indeed, in the early days of aviation those predations cost so many
> lives that government agencies had to step in, requiring the
> manufacturers of aircraft engines to justify their claims of power and
> durability.
>
> ------------------------------------------------------
>
> All of which tends to leave the average homebuilder with more
> questions than answers. Fortunately, the ENGINES themselves are
> incapable of lying, especially when it comes to FUEL CONSUMPTION.
>
> The Specific Fuel Consumption (SFC) of all -- ALL -- air-cooled,
> gasoline-fueled, normally aspirated Otto-cycle engines is clumped near
> the 0.5 mark, meaning it takes about 0.5 POUNDS of 'gasoline' (*) per
> HOUR to produce ONE HORSEPOWER'S worth of torque at the crankshaft.
> For aviation gasoline that works out to about 12bhp per gallon per
> hour. For a 103hp engine that works out to 8.58 gph.

Liquid cooling is simply so superior that the air cooled gasoline-and
even (see Deutz) diesel-is a museum piece per se. That said the Harley
conversion seems to be working out better than anyone would have
thought.

[Bret Ludwig]

>
> > Bill Daniels
>
> The cooling systems on motorcycle engines do not have sufficient coolant
> flow to keep the head from over heating under prolonged running at 3/4
> to full output. The water craft and snowmobile engines may have better
> flow but these also have access to lower temp coolant.
>
> Honda makes a personal water craft that has a hot little 4 banger engine
> that I thought might do the job. It would take some testing to see what
> it's sustained power level would be.

Car engines now are designed for full throttle continuous operation
because that's how the Germans run them. Actually another application
that does that, is the common school bus. Underpowered, they are run
flat out for a long time sometimes. Most now use diesels that are way
too heavy to fly, but when they ran Chevies, they ran a regular old
four bolt forged crank SBC.

[Bret Ludwig]

On Feb 6, 1:20 pm, cavalamb himself > wrote:
> RST Engineering wrote:
> > Come on, Bob. How do you expect the EAA to make a buck out of something as
> > useful as this? Sheesh, man, cherchez le dinero.
>
> > Jim
>
> >>Indeed, these things are so simple -- and so fundamental to engines --
> >>that it is difficult to understand why the EAA does NOT endorse a
> >>program of publicly testing engines at its annual convention.
>
> Endorsement would equate to liability.
>
> BEsides, EAA has never really been about the reality of it - they
> sell the dream.

Fantasy, even.

[Bret Ludwig]

>
> I didn't verify it but according to a History channel show on Tucker.
> After too many failures of the Tucker engine, Franklin aircraft engines
> were converted to liquid cooling and proved to be reliable and Tucker
> bought the Franklin company to be sure and have an uninterrupted supply
> of engines for his cars. After the bankruptcy, the Franklin engine
> company was sold off but I don't know who bought it and I assumed they
> were gone forever. If the Pols are doing a good job at building these
> new Franklin engines, they sure look like a bargain.
>

Tucker didn't have a lot of common sense.

[Maxwell[_2_]]

"Bret Ludwig" > wrote in message
...
>
> Car engines now are designed for full throttle continuous operation
> because that's how the Germans run them. Actually another application
> that does that, is the common school bus. Underpowered, they are run
> flat out for a long time sometimes. Most now use diesels that are way
> too heavy to fly, but when they ran Chevies, they ran a regular old
> four bolt forged crank SBC.
>

Back in the late 70s I drove a Chevy flatbed dump truck powered by a 350.
Always hauled a 8000 lb Ditch Witch and pulled a 16000 lb Case back hoe. Had
to run flat on the floor every where I went. Never had any problems, even in
summer. Did have a nice sized radiator though.

I think of that rig every time I hear someone claim that auto engines won't
survive at high power settings.

[Highflyer]

"Bret Ludwig" > wrote in message
...
>
>>
>> I didn't verify it but according to a History channel show on Tucker.
>> After too many failures of the Tucker engine, Franklin aircraft engines
>> were converted to liquid cooling and proved to be reliable and Tucker
>> bought the Franklin company to be sure and have an uninterrupted supply
>> of engines for his cars. After the bankruptcy, the Franklin engine
>> company was sold off but I don't know who bought it and I assumed they
>> were gone forever. If the Pols are doing a good job at building these
>> new Franklin engines, they sure look like a bargain.
>>
>
> Tucker didn't have a lot of common sense.

The Franklin engine company was alive and well in the late 60's in upstate
New York. I worked with them when they were developing the new line of
Franklin Aircraft engines. These were a twin, a four cylinder and a six
cylinder engine that all used the same cylinders and valves. They brought
them out first as an engine kit for homebuilders. However that didn't go
over very well because at that time there were not all that many homebuilts
and most did not want to spend the money for a new engine. Even as a kit.
When they finally went under financially the rights to the engines were sold
to PZL in poland who continued to produce the engines until recently.

Highflyer
Highflight Aviation Services
Pinckneyville Airport, PJY
Note: rec.aviation.homebuilt annual flyin at Pinckneyville is coming up May
16,17, and 18th. See the faq at http://www.ousterhout.net/pjy-faq.html and
do let Mary know at so she knows how many groceries to lay
in.

[Jim Logajan]

"Highflyer" > wrote:
> The Franklin engine company was alive and well in the late 60's in
> upstate New York. I worked with them when they were developing the
> new line of Franklin Aircraft engines. These were a twin, a four
> cylinder and a six cylinder engine that all used the same cylinders
> and valves. They brought them out first as an engine kit for
> homebuilders. However that didn't go over very well because at that
> time there were not all that many homebuilts and most did not want to
> spend the money for a new engine. Even as a kit. When they finally
> went under financially the rights to the engines were sold to PZL in
> poland who continued to produce the engines until recently.

Do you know who, if anyone, is producing them now? Also, are the guys at
this firm:

http://www.franklinengines.com/

just U.S. distributers or are they actually making them now?

[Anthony W]

Highflyer wrote:

> The Franklin engine company was alive and well in the late 60's in upstate
> New York. I worked with them when they were developing the new line of
> Franklin Aircraft engines. These were a twin, a four cylinder and a six
> cylinder engine that all used the same cylinders and valves. They brought
> them out first as an engine kit for homebuilders. However that didn't go
> over very well because at that time there were not all that many homebuilts
> and most did not want to spend the money for a new engine. Even as a kit.
> When they finally went under financially the rights to the engines were sold
> to PZL in poland who continued to produce the engines until recently.
>
> Highflyer

Are you saying that PLZ is no longer making Franklin engines?

Tony