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tfarin(at)farin.com
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 Posted: Wed Aug 02, 2006 5:50 pm Post subject: Engine Choices for Zodiac XL |
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Folks,
0
First let me compliment the posters on this subject for not trashing each other's viewpoints and turning this discussion into a war.
0
I'm a new builder and thought I'd share my thoughts on the subject. I'm working on the XL tail section and have three Corvair core engines I'm in the process of disassembling. But I also went up in the Jabiru equipped factory XL at the Romeoville, IL Sport Pilot fly in. And I just returned from Oshkosh.
0
I haven't seen this posted to the list although many of you are aware of the fact the Zenith both had both a Jabiru equipped XL and a Corvair equipped XL. The Corvair equipped XL was WW's plane and he spent a fair amount of time in the Zenith booth.
0
I sat through two WW presentations and talked extensively with William and Gus from the WW operation and with the Zenith factory reps. One of the factory reps (who I won't mention by name) told me if he was to build an XL personally, he'd build one with a Corvair engine. Do I consider any of this to be a formal endorsement of Corvair power by Zenith? No. But It does make me feel better about the direction in which I am headed.
0
One of the posters indicated he felt some folks doing automotive conversions were doing so for the wrong reasons. I'm not sure which auto conversions he was discussing. And I'm not sure which reasons were the "wrong reason". Here are the three most common reasons I can think of for doing a Corvair conversion.
0
1. Cost - there is no question an auto conversion is going to be cheaper than a new Jabiru or Rotax. It is highly probable that a Corvair conversion will also be cheaper than a rebuild of an O-200. I'm aware some are claiming an O-200 build can be done for $4,000. I've been watching prices of O-200s on eBay. Based on what I've seen, coming in significantly under $12,000 for a rebuilt engine (without starting with a core) would be an accomplishment.
0
2. Education/Maintenance - There is no question in my mind I will learn a whole lot more building an engine myself than taking delivery of a new or rebuilt engine in a crate. In turn, I'm going to be in much better shape to do maintenance and repairs myself including field repairs.
0
3. Satisfaction - Isn't this one of the reasons many of us are building Zodiacs, either from kits or from scratch? In fact, couldn't the same three reasons be given for our decisions to build kits or scratchbuild the airframe itself.
0
Here are the reasons I've heard given for not doing an auto conversion. I've added my reactions to the arguments.
1. Ignition system redundancy - Because much of the WW conversion offers redundancy for almost the entire ignition system, a large point is made of the fact there are not two spark plugs per cylinder. An inoperative spark plug is a big issue on a 4 cylinder engine. It is much less so on a six. There is at least one ducumented case of a Corvair landing without any particular drama with one of the spark plug totally out of the head.
0
2. Inappropriate Design for aviation - Most of the discussion relating to corvairs relates to crankshaft issues. Corvairs have been flying in aircraft since the Corvair was introduced in 1960. Only recently have crank issues surfaced, for the most part on engines with increased horespower, or extended cranks, and non-nitrided cranks. I've read every piece of material on Corvair crank failures I can lay my hands on. There is no history I can find of crank failures on Corvairs with nitrided cranks built to produce 100 hp without crank extensions. The other problems I've heard aout with Corvair powered Experimentals involve components that are also found on aviation purposed engines that appear to be subject to the same problems.
0
3. Parts availability in the field (Podunk, NE) and field maintenance - This may be a valid point if looking for parts or maintenance if the alternative is a Continental or Lycoming engine. But I'd bet It would be easier to come up with a Corvair part than a Jabiru or Rotax part in a remote location. If A&Es don't like to work on experimentals, would they feel good about and be qualified to work on a Roitax or Jabiru engine? I'm asking. I don't know the answer.
0
4. Resale value - Given that only a few Corvair powered XLs are flying, I'm not sure anyone knows the answer to this question. There is a strong Corvair community. And I've seen partially complete WW Corvair conversions go on eBay for more than the builder had in the engine.
0
5. Safety - Some have claimed that building an auto conversion adds to the crash statistics. I suppose that is likely to be a correct statement although I've seen no statistics to support it. But couldn't the same be said for scratch building or kit building an airframe? Someone said they cringe every time they read about a crash of an auto conversion. I cringed when I read the FAA report about the Zodiac whos wings folded up killing both the flight instructor and the owner. My son really cringed when he close up witnessed what a WW2 dive bomber can do to a Vans RV on the taxiway at Oshkosh last week. Let's face it. Flying is risky.
0
So here's where I'm at. I'm building a Zodiac XL knowing full well the risk is higher that I'll crash with a plane I build myself than if I bought a factory built airplane. The same is true of the engine. I'm going to begin building a Corvair engine and a Zodiac XL. Actually I'm about half way through the XL's tail. Along the way I'm going to learn a hell of a lot about building both planes and engines. As I proceed I'm going to keep asking myself two questions. Do you feel good enough about the job you are doing in building this airframe to bet your life on your skills? Do you feel good enough about the the job you are doing building this engine and what else you have learned about its safety to bet your life on your skills and knowledge?
0
In a few years from now when both are nearly complete I'll have to make a decision. It will come down to three choices.
1. Don't fly the plane or the engine. I'll have learned a hell of a lot about both and I'm likely to recover most of my investment. If I don't get it all back, I'll consider the difference as an investment in my education and an enjoyable hobby. Probably a whole lot cheaper than owning a boat or playing golf.
0
2. Buy an aviation purposed engine and fly the Zodiac. I'll either sell the Corvair engine for close to what I have in it or drop it in a Corvair automobile. And I'll be much better prepared to maintain my aviation purposed engine. 0
0
3. Fly a Corvair powered Zodiac and take the risk. But it will be a calculated risk. And in my mind that's what Experimental aviation is all about.
0
Thanks for listening.
0
Tom Farin
0
0
0
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pacificpainting(at)comcas
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| Posted: Wed Aug 02, 2006 6:21 pm Post subject: Engine Choices for Zodiac XL |
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Not to add fuel to any future fire on this subject. I would probably use a
Corvair engine if I could but not enough power for an 801. There is a lot of
good information on this list. I really enjoy reading all of the ideas that
are presented here. I don't know of any place you could find that everyone
agrees on a single subject. My suggestion, for what it's worth, is take all
the information you want or need and either ignore or delete the rest.
So There.
Dave in Salem
801
Do not archive.
---
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Ron Lendon
Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI
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| Posted: Wed Aug 02, 2006 9:44 pm Post subject: Re: Engine Choices for Zodiac XL |
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Very well said. Flying is risky. I am also building an XL and have 1 corvair core, looking for more, and will be thrilled to fly it with that engine.
I hired in to Chevrolet Engineering in 1979 and have always had an affinity for the Bow Tie logo. Now there is no more Chevrolet Engineering, it went through several name changes, but I do still work at the GM Tech Center and still love them Chevys'.
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_________________
Ron Lendon
WW Corvair with Roy's Garage 5th bearing
CH 601 XLB
N601LT - Flying
http://www.mykitlog.com/rlendon
Corvair Engine Prints:
https://sites.google.com/site/corvairenginedata/ |
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pmaxpmax(at)HOTMAIL.COM
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| Posted: Thu Aug 03, 2006 2:31 am Post subject: Engine Choices for Zodiac XL |
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Tom,
Well said! I agree.
Phil Maxson
601XL/Corvair
Northwest New Jersey
Do Not Archive
| Quote: | From: "Tom Farin" <tfarin(at)farin.com>
Reply-To: zenith-list(at)matronics.com
To: <zenith-list(at)matronics.com>
Subject: Engine Choices for Zodiac XL
Date: Wed, 2 Aug 2006 20:53:25 -0500
Folks,
First let me compliment the posters on this subject for not trashing each
other's viewpoints and turning this discussion into a war.
<<SNIP>>
|
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davgray(at)sbcglobal.net
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| Posted: Thu Aug 03, 2006 3:12 am Post subject: Engine Choices for Zodiac XL |
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Tom
Nice Post, This covers my point of view. I think you have the correct
approach.
Gary Ray
---
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bill_dom(at)yahoo.com
Guest
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| Posted: Thu Aug 03, 2006 4:55 am Post subject: Engine Choices for Zodiac XL |
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This is an excellent post, well said Tom. I enjoy the
topics on engine selection so much that it doesn’t
bother me that much when it goes out of control. In my
case, I already have a Corvair core and that is the
path I would like to pursue. However, since I’m still
years away from hanging an engine into my airframe, I
have the time in my favor and newer information will
hopefully confirm my current choice or will lead me to
look elsewhere.
That why I’m trying to get as much information about
engines as possible and I really appreciate these
threads. This is also what motivated me to start
www.ea-report.com, to collect a good database of real
life experiences about engine reliability and
performance data that I will make available to the
community.
William Dominguez
Plans built Zodiac 601XL
Working on tail
www.ea-report.com
Do not archive
--- Tom Farin <tfarin(at)farin.com> wrote:
| Quote: | Folks,
First let me compliment the posters on this subject
for not trashing each other's viewpoints and turning
this discussion into a war.
I'm a new builder and thought I'd share my thoughts
on the subject. I'm working on the XL tail section
and have three Corvair core engines I'm in the
process of disassembling. But I also went up in the
Jabiru equipped factory XL at the Romeoville, IL
Sport Pilot fly in. And I just returned from
Oshkosh.
I haven't seen this posted to the list although many
of you are aware of the fact the Zenith both had
both a Jabiru equipped XL and a Corvair equipped XL.
The Corvair equipped XL was WW's plane and he spent
a fair amount of time in the Zenith booth.
I sat through two WW presentations and talked
extensively with William and Gus from the WW
operation and with the Zenith factory reps. One of
the factory reps (who I won't mention by name) told
me if he was to build an XL personally, he'd build
one with a Corvair engine. Do I consider any of
this to be a formal endorsement of Corvair power by
Zenith? No. But It does make me feel better about
the direction in which I am headed.
One of the posters indicated he felt some folks
doing automotive conversions were doing so for the
wrong reasons. I'm not sure which auto conversions
he was discussing. And I'm not sure which reasons
were the "wrong reason". Here are the three most
common reasons I can think of for doing a Corvair
conversion.
1. Cost - there is no question an auto conversion
is going to be cheaper than a new Jabiru or Rotax.
It is highly probable that a Corvair conversion will
also be cheaper than a rebuild of an O-200. I'm
aware some are claiming an O-200 build can be done
for $4,000. I've been watching prices of O-200s on
eBay. Based on what I've seen, coming in
significantly under $12,000 for a rebuilt engine
(without starting with a core) would be an
accomplishment.
2. Education/Maintenance - There is no question in
my mind I will learn a whole lot more building an
engine myself than taking delivery of a new or
rebuilt engine in a crate. In turn, I'm going to be
in much better shape to do maintenance and repairs
myself including field repairs.
3. Satisfaction - Isn't this one of the reasons
many of us are building Zodiacs, either from kits or
from scratch? In fact, couldn't the same three
reasons be given for our decisions to build kits or
scratchbuild the airframe itself.
Here are the reasons I've heard given for not doing
an auto conversion. I've added my reactions to the
arguments.
1. Ignition system redundancy - Because much of the
WW conversion offers redundancy for almost the
entire ignition system, a large point is made of the
fact there are not two spark plugs per cylinder. An
inoperative spark plug is a big issue on a 4
cylinder engine. It is much less so on a six.
There is at least one ducumented case of a Corvair
landing without any particular drama with one of the
spark plug totally out of the head.
2. Inappropriate Design for aviation - Most of the
discussion relating to corvairs relates to
crankshaft issues. Corvairs have been flying in
aircraft since the Corvair was introduced in 1960.
Only recently have crank issues surfaced, for the
most part on engines with increased horespower, or
extended cranks, and non-nitrided cranks. I've read
every piece of material on Corvair crank failures I
can lay my hands on. There is no history I can find
of crank failures on Corvairs with nitrided cranks
built to produce 100 hp without crank extensions.
The other problems I've heard aout with Corvair
powered Experimentals involve components that are
also found on aviation purposed engines that appear
to be subject to the same problems.
3. Parts availability in the field (Podunk, NE) and
field maintenance - This may be a valid point if
looking for parts or maintenance if the alternative
is a Continental or Lycoming engine. But I'd bet It
would be easier to come up with a Corvair part than
a Jabiru or Rotax part in a remote location. If
A&Es don't like to work on experimentals, would they
feel good about and be qualified to work on a Roitax
or Jabiru engine? I'm asking. I don't know the
answer.
4. Resale value - Given that only a few Corvair
powered XLs are flying, I'm not sure anyone knows
the answer to this question. There is a strong
Corvair community. And I've seen partially complete
WW Corvair conversions go on eBay for more than the
builder had in the engine.
5. Safety - Some have claimed that building an auto
conversion adds to the crash statistics. I suppose
that is likely to be a correct statement although
I've seen no statistics to support it. But couldn't
the same be said for scratch building or kit
building an airframe? Someone said they cringe
every time they read about a crash of an auto
conversion. I cringed when I read the FAA report
about the Zodiac whos wings folded up killing both
the flight instructor and the owner. My son really
cringed when he close up witnessed what a WW2 dive
bomber can do to a Vans RV on the taxiway at Oshkosh
last week. Let's face it. Flying is risky.
So here's where I'm at. I'm building a Zodiac XL
knowing full well the risk is higher that I'll crash
with a plane I build myself than if I bought a
factory built airplane. The same is true of the
engine. I'm going to begin building a Corvair
engine and a Zodiac XL. Actually I'm about half way
through the XL's tail. Along the way I'm going to
learn a hell of a lot about building both planes and
engines. As I proceed I'm going to keep asking
myself two questions. Do you feel good enough about
the job you are doing in building this airframe to
bet your life on your skills? Do you feel good
enough about the the job you are doing building this
engine and what else you have learned about its
safety to bet your life on your skills and
knowledge?
In a few years from now when both are nearly
complete I'll have to make a decision. It will come
down to three choices.
1. Don't fly the plane or the engine. I'll have
learned a hell of a lot about both and I'm likely to
recover most of my investment. If I don't get it
all back, I'll consider the difference as an
investment in my education and an enjoyable hobby.
Probably a whole lot cheaper than owning a boat or
playing golf.
2. Buy an aviation purposed engine and fly the
Zodiac. I'll either sell the Corvair engine for
close to what I have in it or drop it in a Corvair
automobile. And I'll be much better prepared to
maintain my aviation purposed engine.
3. Fly a Corvair powered Zodiac and take the risk.
But it will be a calculated risk. And in my mind
that's what Experimental aviation is all about.
Thanks for listening.
Tom Farin
|
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http://www.matronics.com/Navigator?Zenith-List |
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