Orphaned Engine

On Jul 20, 5:05*am, " wrote:
Most Experts Aren’t. *That's something the late Smokey Yunick said
back when I was a seaman deuce. Every month my mail delivers one or
two messages saying it's still true. The messages usually come from
some superbly experienced fellow who has literally spent his life
working on cars or trucks. He is the Local Guru when it comes to
engines for homebuilts and he's taking the time to let me know that
the automotive engineers I like to cite in my articles aren't quite as
bright as I seem to think they are, offering an experience-based
example to prove his point.

Unfortunately, the offered example invariably deals with cars or
trucks, things in which the fellow has a life-time of experience,
whereas automotive in the sense used here, does not, although it could
include them. To an engineer, automotive means something that can move
under its own power. Like an oil tanker, the Space Shuttle, or a gold
dredger.

My usual reaction is to hit the delete key. I get more mail than I
want, most from people with real problem, some of whom I can help. But
it's always sad to hear smart people say dumb things. And on the
whole, these are smart people, even though a life-time of experience
hasn't tipped him off that we're taking about two different meanings
for automotive.

We all start out pretty dumb. As we age we gather information and gain
experience and, assuming a fair share of native wit, we end up a bit
smarter than when we began. Mebbe all this guy needs is a nudge in the
right direction. So you say hello and the odds are the fellow is
having the same problems as everyone else except he was a bit too
proud to say so.

With this type of Expert you'll often discover his life-time of
experience has been with just one type of engine or perhaps one type
of car and he has been trying to transfer that experience to a Corvair
or a Volkswagen and isn't having much luck. I mean, who ever heard of
a head torqued to only eighteen foot-pounds! That has to be wrong...
right?

If the fellow hasn't figured out the meaning of automotive there's a
good chance he won't have any idea in the blue-eyed world about Class
of Service but a good understanding here is the real key to a
successful conversion so you give it a shot.

A car or light truck uses a variable speed, high-rpm, low-torque
engine whose nominal output approximates 25% of its peak output.
Nominal output is defined as the amount of power the engine was
designed to deliver for approximately 98% of its service life. The
only time it’s expected to produce more… that wayward 2%… is when
accelerating or climbing a hill. *Once on the flats -- once you've
reached a Stable State of cruise -- the figures are a good match. *For
hilly regions vehicle manufacturers offer different ratios for the
rear-ends. *Economy takes a hit but over-all, the figures match up.
Respect an engine's Class of Service and you'll be rewarded with 2,000
to 5,000 hours between overhauls.

You can always demand more output from either *type of engine but
doing so will reduce it's service life. With a converted VW, for
example, your Mean Time Before Failure will typically fall from about
2,000 hours in vehicular service to about 200 hours when powering a
plane.

By comparison, an aircraft engine is a single-speed, low-rpm, high-
torque engine whose nominal output approximates 75% of its peak
output. Peak output may be defined further as maximum sustainable
output, and as Peak-sub I, meaning an instantaneous value or dyno
blip, something you might use to impress the newbies.

Since our goal is to produce thrust throuigh the rotation of a
propeller, our primary interest is in the amount of torque that
appears in the crank, and in the propeller's efficiency at a given
rpm. The measurement of thrust is quite simple and articles describing
different types of homebuilt thrust stands have appeared in the
literature and on the internet. You will note that horsepower, which
serves no useful function at this stage, has not been mentioned.

It usually takes an exchange of half a dozen messages or thereabouts
to arrive at this point, if in fact we arrive at all. In the
overwhelming majority of cases the Local Expert simply vanishes. Which
is doubly unfortunate because the best is yet to come.

When we convert an auto engine for use in an airplane we are trying to
convert it from one Class of Operation to another to make it more
suitable, usually in the area of mechanical reliability. By
comparison, the typical flying Volkswagen starts out as a marginally
suitable auto engine that is then made even less suitable for aircraft
use by turning it into a hot-rod enigine. Why? Usually because the
person doing the conversion has little understanding of an aircraft
powerplant. *Indeed, most such experts are merely the local Guru grown
old, selling dune buggy engines to the kiddies. *And after all, it
does fly the plane, right?

So why even bother.

Well.... because we should. *A properly built engine is more
efficient. *It produces the required torque at a lower rpm and wear
increases exponentially with rpm. *That means a properly built engine
uses less fuel to deliver the same thrust and last longer, too.

But a properly built engine is also a lot less expensive to build and
nowdays that's becoming a critical factor.

See that chart down there? *The one title BORE VS STROKE? *(It's
embedded in the article in the blog; you guys on r.a.h. will have to
go dig it out and print yourself a copy.) *The chart shows the bore &
stroke combinations for most common conversions and for everything
using 88mm jugs or larger, or a 78 mm or longer crank, is going to
have to machine the crankcase & heads to match. *What they'll end up
with is a dune-buggy combination -- a high-rpm engine that produces
most of its torque up high. *Itty-bitty toothpick of a prop. *Not very
efficient at all. *Lots of machining to do. *Lots of tricky bits to go
wrong during assembly... which is why some folks don't even offer the
thing assembled.

But it's all a bit of a joke because no matter HOW BIG the engine,
it's MAXIMUM SUSTAINABLE OUTPUT is going to be between 35hp and 45hp.

Yeah, I know -- everybody is selling 80hp and up. *Which is a dyno
blip, not a steady output. *Lotsa cubes is going to get you out of the
weeds quicker but once you get the puppy cleaned up you're flying
behind your basic 40hp engine, depending on the local atmosphere.

The limitation has to do with the heads, not the displacement. *The
cylinder heads only provide enough fin-area to manage the waste-heat
from about 40hp. *Unless its nice and cold or you are nice & high.
But the dune crowd only knows how to build big-bore strokers.

Now go take anohter look at that chart. *Limit your jugs to the stock
85.5mm.s and your cranshaft to a 78mm. *At those sizes there's NO
MACHINING REQUIRED. *Your displacement is 1791cc, your maximum
SUSTAINABLE output is about 45hp and your peak torque is going to come
in at about 2800rpm.

Did I mention that no machining is required?

You've altered your cam timing but you're running a stock cam or a
Schneider 'chugger,' the one used in the orchard-blower engine.
You're running SINGLE PORT HEADS... because you're now an airplane
engine, not a hot-rod. *Your Volumetric Efficiency is pushing 70% and
you're about a $1000 dollars ahead of the game because you haven't had
to buy all that machining and you're using a higher percentage of
stock, off the shelf parts. *You're also running a longer, more
efficient prop -- hopefully one you've carved yourself.

The thing starts on the first flip because it has an efficient
ignition system, one that automatically adjusts itself to the load and
a 20A. electrical system. *But no starter, please. *As it is, it
weighs about twenty pounds less than any engine offered by anyone
else.

But of course, it's not a dune-buggy engine. *And the Instant Experts
will stand in line to damn it with faint praise for that fact alone
even while it flys circles around them and is still going strong when
they're doing their second valve job of the year.

In my opinion, this is the perfect engine for an aerodynamically clean
single-seater, like Bruce Kings little beauty. *Had fate dealt me a
different hand, that's what it would be going into. *It would also be
a good match for a KR-1, the early Jodel, Druine, the Teenie Two and
similar designs.

Kill the parent, you got orphans. *And that applies to engines, too.

-R.S.Hoover

Hello Bob

Nice article as per usual.

How about something more on the Type 4? Most info on this engine seems
to be " That is what the VW engine should have been" or " yeah, the
type 4, now that`s a different story" etc. I am sure I am not the only
one with an interest in the "bigger" veedub, and an in-depth
discussion on what can be done with it and to it, written by an
expert like yourself, would be hugely appreciated. It is heavier than
the T1, less available, and parts are more expensive, but it is still
a flat-4 aircooled VW, ain`t it?

Thank you and regards,

Erik Snyman.

PS. Have you perhaps got something written on the T4 on your blog? If
so, a link, please.

"erik" wrote

Nice article as per usual.

How about something more on the Type 4? Most info on this engine seems
to be " That is what the VW engine should have been" or " yeah, the
type 4, now that`s a different story" etc. I am sure I am not the only
one with an interest in the "bigger" veedub, and an in-depth
discussion on what can be done with it and to it, written by an
expert like yourself, would be hugely appreciated. It is heavier than
the T1, less available, and parts are more expensive, but it is still
a flat-4 aircooled VW, ain`t it?

--- new post starts he ----

As far as that goes, how about a small blurb on the type 1, 2, 3, 4, 5, and
how many other types there are? g

About the time I think I am understanding VW's, someone brings up "type 1,
only," and my eyes start to glaze over. ;-) Like just basic, like what
years, cars they were used in, and the main differences between them.

I had a 72 convertible bug for a while, and don't even know what type it
had!

I wish they had made a 6 cylinder bug engine, with decent heads. That would
be a much better aero engine, me thinks. I'm afraid that 40 HP is not going
to ever be enough for what I want to build.
--
Jim in NC

On Jul 21, 12:58*pm, "Morgans" wrote:

As far as that goes, how about a small blurb on the type 1, 2, 3, 4, 5, and
how many other types there are? g
----------------------------------------------------------------------------

Types? They number in the low HUNDREDS, from the basic beetle or Type
I to some NATO aviation support vehicles, Type 338 and higher.

Volkswagen has ALWAYS reserved 'Type' to define the CHASSIS.

Volkswagen engines have ALWAYS been defined by a number approximating
their displacement: 1100, 1500, etc. What Ami-Ricans refer to as the
'Type 4 engine' is actually three engines, the 1700, 1800 and 2000,
which was installed in about a dozen different vehicles, not counting
the applications from the Industrial Engine Divsion.
---------------------------------------------------------------------------------------------

About the time I think I am understanding VW's, someone brings up "type 1,
only," and my eyes start to glaze over. *;-) *Like just basic, like what
years, cars they were used in, and the main differences between them.
-----------------------------------------------------------------------------------------

Variations to the basic VW engines probably number in the thousands;
you can line up at least a hundred variations in the heads alone.
Since the changes were incorporated within production runs you will
need a full set of Factory Service Manuals to learn the serial numbers
of when such changes started and stopped.

Since the Type 1 used SIX different engines over the years, and ALL of
those included variations, the type vs displacement thingy is a handy
way to determine if a person is just running their mouth or if they
actually know something about VW engines.

But that has little to do with converting a VW engine for flight since
you should base your build on all new, universal replacement parts.
----------------------------------------------------------------------------------------------------

I wish they had made a 6 cylinder bug engine, with decent heads. *That would
be a much better aero engine, me thinks.
----------------------------------------------------------------------------------------------------

They did. It's called the Corvair :-)

-R.S.Hoover

wrote:

Snipped out all the good stuff...

I wish they had made a 6 cylinder bug engine, with decent heads. That would
be a much better aero engine, me thinks.

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

They did. It's called the Corvair :-)

-R.S.Hoover


Not at 260 pounds.


IMHO, the best 80 HP VW engine is the Rotax 912.

On Jul 21, 6:55*pm, cavelamb himself wrote:

Not at 260 pounds.
---------------------------------------------------------------------

Seems a tad high but it really doesn't matter; beggers can't be
choosers. It is available, dirt cheap and reliable. Determine it's
CG and it is reduced to a box on the drawing, waiting to be made
practical by the designer.

The Wright 'Flyer' grossed about 750lbs with Orville onboard. Wing
span of 40 feet. Wing area over 500 square feet. Yet it flew
moderately well (in 1905) with only 12 horsepower. Since those days
we have enjoyed quantum leaps in materials and aeronautical knowledge
-- we've more than enough information to build a reliable airplane
from materials commonly available in the average town. Drop the
bureaucrats out of the equation, solve the logistical problems of
where to build and to fly, and you own the sky, de facto if not de
juri.

Here in the western United States on any winter weekend you can see
hundreds of flying machines doing their thing over the myriad of dry
lakes. Many of these are substantial machines with real aircraft
engines but most are not. Yet they all fly and incidents are low.

wrote in message
...
On Jul 21, 6:55 pm, cavelamb himself wrote:

Not at 260 pounds.
---------------------------------------------------------------------

Seems a tad high but it really doesn't matter; beggers can't be
choosers. It is available, dirt cheap and reliable. Determine it's
CG and it is reduced to a box on the drawing, waiting to be made
practical by the designer.

The Wright 'Flyer' grossed about 750lbs with Orville onboard. Wing
span of 40 feet. Wing area over 500 square feet. Yet it flew
moderately well (in 1905) with only 12 horsepower. Since those days
we have enjoyed quantum leaps in materials and aeronautical knowledge
-- we've more than enough information to build a reliable airplane
from materials commonly available in the average town. Drop the
bureaucrats out of the equation, solve the logistical problems of
where to build and to fly, and you own the sky, de facto if not de
juri.

Here in the western United States on any winter weekend you can see
hundreds of flying machines doing their thing over the myriad of dry
lakes. Many of these are substantial machines with real aircraft
engines but most are not. Yet they all fly and incidents are low.

__________________________________________________ ________

I believe the key to the Wright Brothers success with only 12HP was not the
engine, all up flying weight or the wing area but the propellers.

The props were huge and very slow turning giving them astonishing
efficiency. The total propeller disk area was greater than some WWII
bombers. 100 years on, their propulsive efficiency still exceeds those on
most light aircraft.

I think this is still the key if you want to fly far (if slowly) on a tiny
engine. Make a big slow prop and attach it to a glider-like airframe.

On Jul 22, 6:11*am, "Bill Daniels" bildan@comcast-dot-net wrote:

I believe the key to the Wright Brothers success with only 12HP was not the
engine, all up flying weight or the wing area but the propellers.

The props were huge and very slow turning giving them astonishing
efficiency. *The total propeller disk area was greater than some WWII
bombers. *100 years on, their propulsive efficiency still exceeds those on
most light aircraft.

I think this is still the key if you want to fly far (if slowly) on a tiny
engine. *Make a big slow prop and attach it to a glider-like airframe.
---------------------------------------------------------------------------------------

There's a bit more to it than that :-) What you are seeing is a very
nice MATCH between the forward velocity of the airplane and the
velocity of the thrust-stream (or slug) being generated by the
propeller(s). It is the MATCH of velocities that results in the high
efficiency.

The 102" dia. props (8.5 feet ! ) were clearly a factor in the success
of the 'Flyer' but their arrangement -- crossing the drive-chains so
as to give contra-rotation, and the careful match of the engine's
output (the 'throttle' was not variable; you had 'running' and 'full
blast') to their guesstimated forward velocity was the stuff of
genius. But those are things outside the area in which I hoped to
make my point: That the elements needed to produce a successful
flying machine are presently available to anyone, anywhere in America,
who has a yen to fly.

-R.S.Hoover

On Mon, 21 Jul 2008 20:55:19 -0500, cavelamb himself
wrote:

wrote:

Snipped out all the good stuff...

I wish they had made a 6 cylinder bug engine, with decent heads. That would
be a much better aero engine, me thinks.

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

They did. It's called the Corvair :-)

-R.S.Hoover


Not at 260 pounds.


IMHO, the best 80 HP VW engine is the Rotax 912.


They CAN fly at 235. quite possibly less.
** Posted from http://www.teranews.com **

wrote

Types? They number in the low HUNDREDS, from the basic beetle or Type
I to some NATO aviation support vehicles, Type 338 and higher.

WoW ! ! ! I had NO idea, about all of that!

Since the Type 1 used SIX different engines over the years, and ALL of
those included variations, the type vs displacement thingy is a handy
way to determine if a person is just running their mouth or if they
actually know something about VW engines.

When you say 6 different Type 1 engines, is that difference defined by
displacement, or is there some other designation to differentiate among the
Type 1 engines?

But that has little to do with converting a VW engine for flight since
you should base your build on all new, universal replacement parts.

Are all of the Type 1 cases the same?

Thanks for all of the info, by the way.
--
Jim in NC

On Jul 22, 1:12*pm, "Morgans" wrote:

When you say 6 different Type 1 engines, is that difference defined by
displacement, or is there some other designation to differentiate among the
Type 1 engines?
------------------------------------------------------------------------------------------

Mostly displacement. The original (ie, late thirties through about
1943) was not designated in so far as I know but with a disignator,
possibly because it's spec changed so frequently. But the E-type
engine (1943) became the 1100, then the 1200, 1300, 1500 and 1600.
Within that group of engines were a number of variants some of which
appeared on the logo (1300S) although most did not.

The fact the same basic engine was used in the Sedan (ie, Type I), the
Transporter (type II) and the fastback (type III) is what compounds
the foolishness. And then you ran into all of the variants specific
to type, such as the fuel injected engines.

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

But that has little to do with converting a VW engine for flight since
you should base your build on all new, universal replacement parts.

Are all of the Type 1 cases the same?
------------------------------------------------------------------------------------------

Only if you're talking about the Universal Replacement Crankcase.
Special mounting lugs were installed on the rear of the cases used in
the Transporter, some fuel injected cases did not have provision for a
mechanical fuel pump, the threaded boss for the oil pressure switch
wandered around a bit and so forth.

As a point of interest, the State of California represented a market
larger than all of Canada -- large enough for VW to produce a number
of variations specific to SoCal's smog requirements. Those of us
living here are familiar with those engines whereas a VW mechanic from
another region is liable to have never even seen one.

For the most part, the internals stayed the same. All 1300, 1500 and
1600 engines used the same cam, for example (the 'Transporter Cam' is
a myth). But by the time you got out to the heads you are looking at
dozens of variations, all built in significant numbers. This is where
things begin to get serious because the chamber volume and deck height
must be identical across all four jugs. Try running a pair of mis-
matched heads and you could ltlrash the thing on the first hill.

In my blog I've spent some time talking about blueprinting the parts.
Aside from simply checking them against the spec, blueprinting is
needed to ensure you end up with a collection of parts that are
compatible.
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Thanks for all of the info, by the way.
--------------------------------------------------------------------------------------------------------

You're welcome. But you can find it all in the official manuals. And
in the popular manuals I've mentioned in the TULZ series of articles.
Great Plains offers a manual and video specific to flying
conversions. What you won't find are the lurbrication and durability
mods -- the HVX mods -- that allowed us to turn the VW in something
that could run flat-out for 24 hours. When those mods are
incorporated into a VW converted for flight you end up with a more
efficient, cooler-running engine. However, all of those mods appeared
on the 1700 and later engines (ie, the 'type 4')l and are found on ALL
modern-day engines. Retro-fitting them to your engine simply brings
it up to date.

-R.S.Hoover