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Re; Engine choices

https://www.murphybuilders.net/viewtopic.php?f=1&t=1182

Page 1 of 2

Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by Rob Helt
Hi Mike;
Read with interest re: engines. I found myself in a very similar
situation and like you I have looked into a number of different engine
options. You mention that Murphy would like to see everyone upgrade the
gross if they use the M-14P. Speaking with Bob Patterson he had mentioned
that you can use the engine and not do the upgrade except that you have to
watch your speeds and weight. (Personally I think this scenario can get you
in trouble). Like yourself I didn't want to pay a fortune for an engine and
even though I wanted the M-14 I didn't want to open up my wings again. What
I have purchased is the M-462 which is very similar to the M-14 only not
certified for inverted flight, has a different prop govenor and is rated at
315hp. As well it comes with a overhauled constant speed all metal prop
(V-520) (the Russian M-14 comes with a wooden prop with metal leading edges)
and new exhaust. Cost about 10,500 US exclusive shipping. You would still
need all the other accessories as with the M-14 but hopefully Murphy will be
making a firewall forward kit available. I did post some information to the
list earlier on this engine however let me know if you want some more
information .
Rob Helt
----- Original Message -----
From: "AGT" <agt@mosquitonet.com>
To: <agt@mosquitonet.com>
Sent: Monday, January 15, 2001 10:23 PM
Subject: RE: Engine Mount Fabrication

The complete LS-1 engine installation, including all accessories, is 490
lbs. It's rated at 350HP@5500rpm for takeoff and 300HP@4250rpm
continuous.
That compares favorably to the M14P which allows 360HP for takeoff, but
lists cruise HP at only 200HP. Of course, the M14P only has to turn less
than 3000rpm for that, which is a huge advantage. The other engine of
interest is the Suburu from Crossflow in Ontario. They have three
suitable
engine models ranging from 250HP to 320HP. Two of the three models are
turbocharged, which should be an advantage for high altitude operation.
Interestingly, the 300HP turbocharged model lists a fuel burn of 10.2gph
and
the 320HP high output engine lists 9.1gph. Also, the high output model
apparently gets the extra 20HP from rpm. It's rated 320HP occurs at
6050rpm
versus the 300HP model at 5600rpm. The huge advantage of the Crossflow
engine is that they provide a firewall forward package, including engine
mount, radiators, and other stuff that would be a challenge to engineer
myself. But the scary thing about auto engine conversions for me is high
continuous rpm. At least the LS-1 has two extra cylinders and turns quite
a
bit slower than the Suburu. I've had more than one experience of
cylinders
failing for one reason or another on auto V8s and the engine keeps running
anyway.

I would dearly love to use the M14P, but Murphy is adamant about doing the
gross weight upgrade if the M14P is to be used. I have a lot of my
project
completed already so that would mean tearing into parts that I don't want
to
tear into, such as the sealed and tested wing tank. So off I go,
exploring
other engine options. One thing for sure, I can't afford a $40,000 (or
more) Lycoming and I don't want to keep paying ridiculous prices for parts
to maintain it.

Mike

-----Original Message-----
From: Bob Patterson [mailto:bob.patterson@canrem.com]
Sent: Wednesday, January 10, 2001 3:32 PM
To: Murphy Rebel Builders List
Subject: Re: Engine Mount Fabrication



Hi Mike !

I'm sure the Murphy Tech. Dept. can supply all the needed
measurements - thrust line position, offset, etc. .... They have
done this for the Rebel for several builders.

How heavy is that complete installation, compared to an O-540 ??
How many HP. ?? Perhaps NWA can supply some info on the mounts
others are using ...

.....bobp

---------------------------------orig.---------------------------------
At 11:50 AM 1/10/01 -0900, you wrote:
I am interested in using the Northwest-Aero Chevy LS-1 V8 conversion on
my
Super Rebel. Does anyone have information about the positioning of the
center of thrust (i.e., prop hub location, how the prop shaft is angled,
whatever). I have heard things like 19 inches up from the bottom of the
firewall and angled such that the center of thrust passes through some
place
on the tail. Stuff like that. I have also heard that it is easier to
begin
by suspending the engine from the ceiling over the firewall (or a mock up
of
the firewall). Any other tips or advice on how to fabricate an engine
mount
from scratch?

Mike Kimball
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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by AGT
It appears as if the M462 weighs the same as an M14. And since max power is
only available for short periods, usually used for takeoff, I don't see why
the M462 would be OK for use in an unmodified SR and the M14 would not be
OK. With either engine, one would have to be in a steep descent (probably
very steep) to get anywhere near Vne. The two concerns, gross weight and
Vne would be the same with both engines. That being the case, I'll take the
extra horsepower. Of course, the extra horsepower at takeoff would be
trying to separate the engine from the airplane more, but would it be a
significantly higher force from 315HP to 360HP?

Change tracks...

I spoke to Crossflow about their CF4-33 engines and asked the usual
questions including the big one..."I'm concerned about high rpm?"

He said I shouldn't be thinking in terms of rpm, but rather, piston speed.
He went on to explain that the CF4-33 stroke is about 2 inches versus a
similarly powerful Lycoming with a stroke of 6 inches. This was supposed to
make me feel better since the piston speed would still be reasonable. It
sort of worked, but I still had nagging worries about the high rpm that I
couldn't quite nail down. Later I remembered the valve train. I forgot to
ask him about the more fragile areas, like valves and stuff, that would
still be moving a lot faster in an engine turning 6000 rpm versus the valves
and stuff in an engine turning 3000 rpm.

The description of how they ship the engine sounded very cool. Apparently,
they bolt the engine to the side of the crate as if it were being bolted to
your airplane. All accessories are mounted on the engine. You don't have
to figure out where everything goes.

I searched around on the web to see if I could find out more about the
CF4-33 engines. The Suburu SVX is the car this engine is used in. I found
lots of complaints on the web about maintenance on this car, but very little
problems with the engine. One thing became very clear from owner comments.
The Suburu SVX is a relatively rare car and parts are not always readily
available. Also, owners of the SVX complained about the high cost of parts.
Now I'm thinking, this doesn't sound much better than owning a Lycoming. If
only Northwest Aero would make a firewall forward package for their LS-1!
If they had a firewall forward package, I think that would be the engine I
would go with.

Mike


-----Original Message-----
From: Rob Helt [mailto:rhelt@csolve.net]
Sent: Monday, January 15, 2001 7:18 PM
To: Murphy Rebel Builders List
Subject: Re; Engine choices


Hi Mike;
Read with interest re: engines. I found myself in a very similar
situation and like you I have looked into a number of different engine
options. You mention that Murphy would like to see everyone upgrade the
gross if they use the M-14P. Speaking with Bob Patterson he had mentioned
that you can use the engine and not do the upgrade except that you have to
watch your speeds and weight. (Personally I think this scenario can get you
in trouble). Like yourself I didn't want to pay a fortune for an engine and
even though I wanted the M-14 I didn't want to open up my wings again. What
I have purchased is the M-462 which is very similar to the M-14 only not
certified for inverted flight, has a different prop govenor and is rated at
315hp. As well it comes with a overhauled constant speed all metal prop
(V-520) (the Russian M-14 comes with a wooden prop with metal leading edges)
and new exhaust. Cost about 10,500 US exclusive shipping. You would still
need all the other accessories as with the M-14 but hopefully Murphy will be
making a firewall forward kit available. I did post some information to the
list earlier on this engine however let me know if you want some more
information .
Rob Helt
----- Original Message -----
From: "AGT" <agt@mosquitonet.com>
To: <agt@mosquitonet.com>
Sent: Monday, January 15, 2001 10:23 PM
Subject: RE: Engine Mount Fabrication

The complete LS-1 engine installation, including all accessories, is 490
lbs. It's rated at 350HP@5500rpm for takeoff and 300HP@4250rpm
continuous.
That compares favorably to the M14P which allows 360HP for takeoff, but
lists cruise HP at only 200HP. Of course, the M14P only has to turn less
than 3000rpm for that, which is a huge advantage. The other engine of
interest is the Suburu from Crossflow in Ontario. They have three
suitable
engine models ranging from 250HP to 320HP. Two of the three models are
turbocharged, which should be an advantage for high altitude operation.
Interestingly, the 300HP turbocharged model lists a fuel burn of 10.2gph
and
the 320HP high output engine lists 9.1gph. Also, the high output model
apparently gets the extra 20HP from rpm. It's rated 320HP occurs at
6050rpm
versus the 300HP model at 5600rpm. The huge advantage of the Crossflow
engine is that they provide a firewall forward package, including engine
mount, radiators, and other stuff that would be a challenge to engineer
myself. But the scary thing about auto engine conversions for me is high
continuous rpm. At least the LS-1 has two extra cylinders and turns quite
a
bit slower than the Suburu. I've had more than one experience of
cylinders
failing for one reason or another on auto V8s and the engine keeps running
anyway.

I would dearly love to use the M14P, but Murphy is adamant about doing the
gross weight upgrade if the M14P is to be used. I have a lot of my
project
completed already so that would mean tearing into parts that I don't want
to
tear into, such as the sealed and tested wing tank. So off I go,
exploring
other engine options. One thing for sure, I can't afford a $40,000 (or
more) Lycoming and I don't want to keep paying ridiculous prices for parts
to maintain it.

Mike

-----Original Message-----
From: Bob Patterson [mailto:bob.patterson@canrem.com]
Sent: Wednesday, January 10, 2001 3:32 PM
To: Murphy Rebel Builders List
Subject: Re: Engine Mount Fabrication



Hi Mike !

I'm sure the Murphy Tech. Dept. can supply all the needed
measurements - thrust line position, offset, etc. .... They have
done this for the Rebel for several builders.

How heavy is that complete installation, compared to an O-540 ??
How many HP. ?? Perhaps NWA can supply some info on the mounts
others are using ...

.....bobp

---------------------------------orig.---------------------------------
At 11:50 AM 1/10/01 -0900, you wrote:
I am interested in using the Northwest-Aero Chevy LS-1 V8 conversion on
my
Super Rebel. Does anyone have information about the positioning of the
center of thrust (i.e., prop hub location, how the prop shaft is angled,
whatever). I have heard things like 19 inches up from the bottom of the
firewall and angled such that the center of thrust passes through some
place
on the tail. Stuff like that. I have also heard that it is easier to
begin
by suspending the engine from the ceiling over the firewall (or a mock up
of
the firewall). Any other tips or advice on how to fabricate an engine
mount
from scratch?

Mike Kimball
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---------*

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--------*

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--------*
*---------------------------------------------------------------------------
--------*

*---------------------------------------------------------------------------
--------*
Contributors' page at:
http://www.dcsol.com/murphy-rebel/contributors.htm
Visit the book store at:
http://www.dcsol.com/murphy-rebel/book_store.htm
Archives located at:
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Contributors' page at:
http://www.dcsol.com/murphy-rebel/contributors.htm
Visit the book store at:
http://www.dcsol.com/murphy-rebel/book_store.htm
Archives located at:
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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by Mike Davis
I don't know what the SFC for the Subaru engines is, but from the reports
we've had on actual flying Subarus, it's considerably better than the
typical .435lb per hour per HP which is what Lycoming claims for an O-360-A
series at 75%, or best fuel/air mixture. I'll pose this question to the
airsoob list to see if we can get some real world numbers, and I'll ask
Crossflow what their numbers are.

Mike

----- Original Message -----
From: "Peter & Monica" <capete@sympatico.ca>
To: " (Murphy Rebel Builders List)" <murphy-rebel@dcsol.com>
Sent: Tuesday, January 16, 2001 11:32 PM
Subject: Re: Re; Engine choices

What percent of rated horsepower are these fuel burns derived from? That
will tell you
how efficient an engine is. All gasoline piston engines fall within a
narrow range of
efficiency which = "specific fuel consumption" (SFC)

According to the math, Crossflow's fuel burn numbers on the 300 HP
indicate a 50% power
setting. An SR at 150 HP will not be cruising very fast.

Peter Kopasovic SR003

lt
----- Original Message -----
From: "AGT" <agt@mosquitonet.com>
To: <agt@mosquitonet.com>
Sent: Monday, January 15, 2001 10:23 PM
Subject: RE: Engine Mount Fabrication
The complete LS-1 engine installation, including all accessories, is
490
lbs. It's rated at 350HP@5500rpm for takeoff and 300HP@4250rpm
continuous.
That compares favorably to the M14P which allows 360HP for takeoff,
but
lists cruise HP at only 200HP. Of course, the M14P only has to turn
less
than 3000rpm for that, which is a huge advantage. The other engine of
interest is the Suburu from Crossflow in Ontario. They have three
suitable
engine models ranging from 250HP to 320HP. Two of the three models
are
turbocharged, which should be an advantage for high altitude
operation.
Interestingly, the 300HP turbocharged model lists a fuel burn of
10.2gph
and
the 320HP high output engine lists 9.1gph. Also, the high output
model
apparently gets the extra 20HP from rpm. It's rated 320HP occurs at
6050rpm
versus the 300HP model at 5600rpm. The huge advantage of the
Crossflow
engine is that they provide a firewall forward package, including
engine
mount, radiators, and other stuff that would be a challenge to
engineer
myself. But the scary thing about auto engine conversions for me is
high
continuous rpm. At least the LS-1 has two extra cylinders and turns
quite
a
bit slower than the Suburu. I've had more than one experience of
cylinders
failing for one reason or another on auto V8s and the engine keeps
running
anyway.

I would dearly love to use the M14P, but Murphy is adamant about doing
the
gross weight upgrade if the M14P is to be used. I have a lot of my
project
completed already so that would mean tearing into parts that I don't
want
to
tear into, such as the sealed and tested wing tank. So off I go,
exploring
other engine options. One thing for sure, I can't afford a $40,000
(or
more) Lycoming and I don't want to keep paying ridiculous prices for
parts
to maintain it.

Mike

-----Original Message-----
From: Bob Patterson [mailto:bob.patterson@canrem.com]
Sent: Wednesday, January 10, 2001 3:32 PM
To: Murphy Rebel Builders List
Subject: Re: Engine Mount Fabrication



Hi Mike !

I'm sure the Murphy Tech. Dept. can supply all the needed
measurements - thrust line position, offset, etc. .... They have
done this for the Rebel for several builders.

How heavy is that complete installation, compared to an O-540
??
How many HP. ?? Perhaps NWA can supply some info on the mounts
others are using ...

.....bobp
---------------------------------orig.---------------------------------
At 11:50 AM 1/10/01 -0900, you wrote:
on
my
the
angled,
the
some
place
to
begin
mock up
of
engine
mount
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--------*
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--------*
*---------------------------------------------------------------------------
--------*
*---------------------------------------------------------------------------
--------*

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Contributors' page at:
http://www.dcsol.com/murphy-rebel/contributors.htm
Visit the book store at:
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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by Mike Davis
I looked at Crossflow's site, and the fuel flow for the 320HP model is
stated as "9 10.5". Since the 300HP model is 10.2, the 320 most likely is
10.5... I think the 9 is just a typo.

Mike

----- Original Message -----
From: "AGT" <agt@mosquitonet.com>
To: "'Murphy Rebel Builders List'" <murphy-rebel@dcsol.com>
Sent: Tuesday, January 16, 2001 6:54 PM
Subject: RE: Re; Engine choices
The complete LS-1 engine installation, including all accessories, is 490
lbs. It's rated at 350HP@5500rpm for takeoff and 300HP@4250rpm
continuous.
That compares favorably to the M14P which allows 360HP for takeoff, but
lists cruise HP at only 200HP. Of course, the M14P only has to turn
less
than 3000rpm for that, which is a huge advantage. The other engine of
interest is the Suburu from Crossflow in Ontario. They have three
suitable
engine models ranging from 250HP to 320HP. Two of the three models are
turbocharged, which should be an advantage for high altitude operation.
Interestingly, the 300HP turbocharged model lists a fuel burn of 10.2gph
and
the 320HP high output engine lists 9.1gph. Also, the high output model
apparently gets the extra 20HP from rpm. It's rated 320HP occurs at
6050rpm
versus the 300HP model at 5600rpm. The huge advantage of the Crossflow
engine is that they provide a firewall forward package, including engine
mount, radiators, and other stuff that would be a challenge to engineer
myself. But the scary thing about auto engine conversions for me is
high
continuous rpm. At least the LS-1 has two extra cylinders and turns
quite
a
bit slower than the Suburu. I've had more than one experience of
cylinders
failing for one reason or another on auto V8s and the engine keeps
running
anyway.

I would dearly love to use the M14P, but Murphy is adamant about doing
the
gross weight upgrade if the M14P is to be used. I have a lot of my
project
completed already so that would mean tearing into parts that I don't
want
to
tear into, such as the sealed and tested wing tank. So off I go,
exploring
other engine options. One thing for sure, I can't afford a $40,000 (or
more) Lycoming and I don't want to keep paying ridiculous prices for
parts
to maintain it.

Mike

-----Original Message-----
From: Bob Patterson [mailto:bob.patterson@canrem.com]
Sent: Wednesday, January 10, 2001 3:32 PM
To: Murphy Rebel Builders List
Subject: Re: Engine Mount Fabrication



Hi Mike !

I'm sure the Murphy Tech. Dept. can supply all the needed
measurements - thrust line position, offset, etc. .... They have
done this for the Rebel for several builders.

How heavy is that complete installation, compared to an O-540 ??
How many HP. ?? Perhaps NWA can supply some info on the mounts
others are using ...

.....bobp

---------------------------------orig.---------------------------------
At 11:50 AM 1/10/01 -0900, you wrote:
I am interested in using the Northwest-Aero Chevy LS-1 V8 conversion on
my
Super Rebel. Does anyone have information about the positioning of the
center of thrust (i.e., prop hub location, how the prop shaft is
angled,
whatever). I have heard things like 19 inches up from the bottom of
the
firewall and angled such that the center of thrust passes through some
place
on the tail. Stuff like that. I have also heard that it is easier to
begin
by suspending the engine from the ceiling over the firewall (or a mock
up
of
the firewall). Any other tips or advice on how to fabricate an engine
mount
from scratch?

Mike Kimball
*--------------------------------------------------------------------------
*--------------------------------------------------------------------------
---------*

*---------------------------------------------------------------------------
*---------------------------------------------------------------------------
--------*

*---------------------------------------------------------------------------
*---------------------------------------------------------------------------
--------*

*---------------------------------------------------------------------------
*---------------------------------------------------------------------------
--------*

*---------------------------------------------------------------------------
--------*
*---------------------------------------------------------------------------
--------*

*-----------------------------------------------------------------------------------*
Contributors' page at:
http://www.dcsol.com/murphy-rebel/contributors.htm
Visit the book store at:
http://www.dcsol.com/murphy-rebel/book_store.htm
Archives located at:
http://www.dcsol.com/murphy-rebel/archives.htm
*-----------------------------------------------------------------------------------*




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

Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by Peter & Monica
What percent of rated horsepower are these fuel burns derived from? That will tell you
how efficient an engine is. All gasoline piston engines fall within a narrow range of
efficiency which = "specific fuel consumption" (SFC)

According to the math, Crossflow's fuel burn numbers on the 300 HP indicate a 50% power
setting. An SR at 150 HP will not be cruising very fast.

Peter Kopasovic SR003

lt
----- Original Message -----
From: "AGT" <agt@mosquitonet.com>
To: <agt@mosquitonet.com>
Sent: Monday, January 15, 2001 10:23 PM
Subject: RE: Engine Mount Fabrication
The complete LS-1 engine installation, including all accessories, is 490
lbs. It's rated at 350HP@5500rpm for takeoff and 300HP@4250rpm
continuous.
That compares favorably to the M14P which allows 360HP for takeoff, but
lists cruise HP at only 200HP. Of course, the M14P only has to turn less
than 3000rpm for that, which is a huge advantage. The other engine of
interest is the Suburu from Crossflow in Ontario. They have three
suitable
engine models ranging from 250HP to 320HP. Two of the three models are
turbocharged, which should be an advantage for high altitude operation.
Interestingly, the 300HP turbocharged model lists a fuel burn of 10.2gph
and
the 320HP high output engine lists 9.1gph. Also, the high output model
apparently gets the extra 20HP from rpm. It's rated 320HP occurs at
6050rpm
versus the 300HP model at 5600rpm. The huge advantage of the Crossflow
engine is that they provide a firewall forward package, including engine
mount, radiators, and other stuff that would be a challenge to engineer
myself. But the scary thing about auto engine conversions for me is high
continuous rpm. At least the LS-1 has two extra cylinders and turns quite
a
bit slower than the Suburu. I've had more than one experience of
cylinders
failing for one reason or another on auto V8s and the engine keeps running
anyway.

I would dearly love to use the M14P, but Murphy is adamant about doing the
gross weight upgrade if the M14P is to be used. I have a lot of my
project
completed already so that would mean tearing into parts that I don't want
to
tear into, such as the sealed and tested wing tank. So off I go,
exploring
other engine options. One thing for sure, I can't afford a $40,000 (or
more) Lycoming and I don't want to keep paying ridiculous prices for parts
to maintain it.

Mike

-----Original Message-----
From: Bob Patterson [mailto:bob.patterson@canrem.com]
Sent: Wednesday, January 10, 2001 3:32 PM
To: Murphy Rebel Builders List
Subject: Re: Engine Mount Fabrication



Hi Mike !

I'm sure the Murphy Tech. Dept. can supply all the needed
measurements - thrust line position, offset, etc. .... They have
done this for the Rebel for several builders.

How heavy is that complete installation, compared to an O-540 ??
How many HP. ?? Perhaps NWA can supply some info on the mounts
others are using ...

.....bobp

---------------------------------orig.---------------------------------
At 11:50 AM 1/10/01 -0900, you wrote:
I am interested in using the Northwest-Aero Chevy LS-1 V8 conversion on
my
Super Rebel. Does anyone have information about the positioning of the
center of thrust (i.e., prop hub location, how the prop shaft is angled,
whatever). I have heard things like 19 inches up from the bottom of the
firewall and angled such that the center of thrust passes through some
place
on the tail. Stuff like that. I have also heard that it is easier to
begin
by suspending the engine from the ceiling over the firewall (or a mock up
of
the firewall). Any other tips or advice on how to fabricate an engine
mount
from scratch?

Mike Kimball
*--------------------------------------------------------------------------
---------*
*--------------------------------------------------------------------------
---------*

*---------------------------------------------------------------------------
*---------------------------------------------------------------------------
--------*

*---------------------------------------------------------------------------
--------*
*---------------------------------------------------------------------------
--------*

*-----------------------------------------------------------------------------------*
Contributors' page at:
http://www.dcsol.com/murphy-rebel/contributors.htm
Visit the book store at:
http://www.dcsol.com/murphy-rebel/book_store.htm
Archives located at:
http://www.dcsol.com/murphy-rebel/archives.htm
*-----------------------------------------------------------------------------------*
*-----------------------------------------------------------------------------------*
Contributors' page at:
http://www.dcsol.com/murphy-rebel/contributors.htm
Visit the book store at:
http://www.dcsol.com/murphy-rebel/book_store.htm
Archives located at:
http://www.dcsol.com/murphy-rebel/archives.htm
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-----------------------------------------------------------------

Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by Mike Davis
Oops, guess I should read both airsoob and murphy-rebel before posting my
messages. Thanks David, guess everyone got this info twice.

Mike

----- Original Message -----
From: "David M Parrish" <dmp@radbsd.mcg.edu>
To: "Murphy Rebel Builders List" <murphy-rebel@dcsol.com>
Sent: Wednesday, January 17, 2001 5:37 AM
Subject: Re: Re; Engine choices

On 16 Jan 2001, at 21:45, Mike Davis wrote:
I don't know what the SFC for the Subaru engines is, but from the
reports we've had on actual flying Subarus, it's considerably better
than the typical .435lb per hour per HP which is what Lycoming claims
for an O-360-A series at 75%, or best fuel/air mixture. I'll pose
The EG-33 BSFC's:

3000RPM 120HP 0.436 (Best BSFC)
4800RPM 211HP 0.462 (Torque peak)
5400RPM 230HP 0.482 (HP peak)

Still, it's hard to compare. The standard conditions for the rated
HP's are different for aero and auto engines. Auto HP charts are for
full throttle sea level and can't be set to run lean of peak. (How
many O-360's can be realisticly be run lean of peak?)

---
David Parrish





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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by David M Parrish
On 16 Jan 2001, at 18:54, AGT wrote:
He said I shouldn't be thinking in terms of rpm, but rather, piston
speed. He went on to explain that the CF4-33 stroke is about 2 inches
versus a similarly powerful Lycoming with a stroke of 6 inches. This
was supposed to make me feel better since the piston speed would still
The SVX engine (AKA EG-33) has bore of 3.82" and a stroke of
2.95". The IO-360 is 5.125 x 4.375". So an IO-360 turning at
2400RPM would be equivalent to a EG-33 turning at about 3600 for
the same piston speed. (EG-33 is 230HP@5400RPM stock)

BUT. The IO's piston and rod are much more massive than the
EG's, increasing the forces. (The IO's piston area is almost twice
that of the EG, so mass is probably more that twice.)
remembered the valve train. I forgot to ask him about the more
fragile areas, like valves and stuff, that would still be moving a lot
faster in an engine turning 6000 rpm versus the valves and stuff in an
Those are four tiny valves compared to two huge ones.
from owner comments. The Suburu SVX is a relatively rare car and parts
are not always readily available. Also, owners of the SVX complained
about the high cost of parts. Now I'm thinking, this doesn't sound
High compared to other cars. I just heard from someone that you
can get a new EG-33 long block from Subaru for about $6400US.
How much is an O-540 crank? I also suspect that the EG-33 has
many parts that are common with the EJ-22 four, which was used
extensively by Subaru. (I may be totally off on that one.)

Subaru has also come out with a new engine that's in the LL Bean
edition Forester, which should be very popular. A 212HP six that's
only an inch longer than the EJ-25 four and a hundred pounds
heavier.

---
David Parrish

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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by David M Parrish
On 16 Jan 2001, at 21:45, Mike Davis wrote:
I don't know what the SFC for the Subaru engines is, but from the
reports we've had on actual flying Subarus, it's considerably better
than the typical .435lb per hour per HP which is what Lycoming claims
for an O-360-A series at 75%, or best fuel/air mixture. I'll pose
The EG-33 BSFC's:

3000RPM 120HP 0.436 (Best BSFC)
4800RPM 211HP 0.462 (Torque peak)
5400RPM 230HP 0.482 (HP peak)

Still, it's hard to compare. The standard conditions for the rated
HP's are different for aero and auto engines. Auto HP charts are for
full throttle sea level and can't be set to run lean of peak. (How
many O-360's can be realisticly be run lean of peak?)

---
David Parrish





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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by klehman
With aftermarket electronics you can definately do better on sfc than
the car does. You can cruise the subaru leaner since we don't have to
keep the mixture rich enough to keep the catalytic converter running
which is largely what the oxygen sensor exists in the car for.

However from what I've seen so far, I flat out don't believe anybody who
claims better than about 0.37 for any auto conversion, especially if
they are running at high rpm. Usually they are overestimating the power
being produced. I think the 0.435 Lycoming figure is also a best cruise
number that is often not achieved though, so .37 or .38 in cruise is
darn good.

Ken

Mike Davis wrote:
I don't know what the SFC for the Subaru engines is, but from the reports
we've had on actual flying Subarus, it's considerably better than the
typical .435lb per hour per HP which is what Lycoming claims for an O-360-A
series at 75%, or best fuel/air mixture. I'll pose this question to
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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by Mike Davis
I want to know if at the end of the term we can repeat that and actually
sound like we understand that if we can all get degrees? Really though, I
love seeing it analyzed so logically.

Mike

----- Original Message -----
From: <Legeorgen@cs.com>
To: <murphy-rebel@dcsol.com>
Sent: Wednesday, January 17, 2001 6:33 PM
Subject: Re: Re; Engine choices

Hey Dave, could you repeat that first part again, in English?

Bruce 357R
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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by Legeorgen
Hey Dave, could you repeat that first part again, in English?

Bruce 357R
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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by David Ricker
Comments below:

David M Parrish wrote:
On 16 Jan 2001, at 18:54, AGT wrote:
He said I shouldn't be thinking in terms of rpm, but rather, piston
speed. He went on to explain that the CF4-33 stroke is about 2 inches
versus a similarly powerful Lycoming with a stroke of 6 inches. This
was supposed to make me feel better since the piston speed would still
The SVX engine (AKA EG-33) has bore of 3.82" and a stroke of
2.95". The IO-360 is 5.125 x 4.375". So an IO-360 turning at
2400RPM would be equivalent to a EG-33 turning at about 3600 for
the same piston speed. (EG-33 is 230HP@5400RPM stock)

BUT. The IO's piston and rod are much more massive than the
EG's, increasing the forces. (The IO's piston area is almost twice
that of the EG, so mass is probably more that twice.)
You are on the right track here, the shorter stroke can turn higher RPMs because of lower
peak velocities and accelerations. Also, the lower piston/rod weight makes the stress on
the parts less (of course you must account for the different mass/strength of the parts
when you look at this.....). Remember the equation: F=MA Force = Mass x Acceleration,
that you might have run into at school? Newtons first law if I remember correctly but it
has been too long! For a rod of the same strength (ie breaking force), the acceleration
(or deceleration, related to velocity) of the piston can be higher if the piston has a
lower mass.

The force required to decelerate the piston depends on its' energy which is related to
the velocity squared and the mass of the piston/rod. That is to say Energy=(MV^2)/2.
The Energy here is the kinetic energy of the piston/rod (Mass) that must be dissipated
every time it goes from peak Velocity to a stop at the ends of the stroke. You can see
here that the relationship between RPM and loading on the connecting rod is not strictly
linear but depends on the mass of the parts and the velocity (RPM). The automotive
engines will win out here because of shorter strokes and lighter piston/rods. Of course
aircraft engines are probably tuned to turn more slowly to keep prop tip speed lower so
they would optimize the RPM/stress issues with that in mind.
remembered the valve train. I forgot to ask him about the more
fragile areas, like valves and stuff, that would still be moving a lot
faster in an engine turning 6000 rpm versus the valves and stuff in an
Those are four tiny valves compared to two huge ones.
Correct. These days automotive valves are much lighter than in aircraft and thus can
accelerate to higher speeds and slow down much faster with lighter valve spring rates
without damage and without problems from valve float etc. For an interesting
comparision look at the typical NASCAR stock car which uses the "same" pushrod valve
train as the Lycoming and can tolerate 9000 RPM without floating valves etc. Admittedly
this is an extreme case with a shorter expected life but it goes to show that automotive
technology is adapted to tolerate higher RPMs. Another example is my early 1.6 Hemi
Corolla with pushrod valves which would happily tolerate 7000+ RPM without
modifications. OK, I am being long winded but the point is that the inertia in the
typical automotive valve train, particularly overhead cams can tolerate much higher RPMs
than the design chosen for aircraft.

OK, at the end of this how do we come out with auto vs aircraft? I'm not sure but if you
look at the typical life of an auto engine at say 100,000 miles between re-builds (and
this is getting to be on the low side) and an average speed of a generous 45 miles an
hour over the lifetime of the car then you will have driven for about 2200 hours, about
the TBO for an aircraft engine. The auto engine starts to look attractive here if you
can eliminate the teething problems with doing your own conversion.........
from owner comments. The Suburu SVX is a relatively rare car and parts
are not always readily available. Also, owners of the SVX complained
about the high cost of parts. Now I'm thinking, this doesn't sound
High compared to other cars. I just heard from someone that you
can get a new EG-33 long block from Subaru for about $6400US.
How much is an O-540 crank? I also suspect that the EG-33 has
many parts that are common with the EJ-22 four, which was used
extensively by Subaru. (I may be totally off on that one.)
I think you have put this into the corect perspective. As for availibility I suspect
dealing with Subaru would be like my experience with Toyota, if you want the part I think
they will find it for you even if they have to make it. I ordered a door for a 15 year
old car & what looked like a brand new one (not dusty!) came from Japan!

Well I hope this helps and sorry about all the Engineerese!

Dave R.

Subaru has also come out with a new engine that's in the LL Bean
edition Forester, which should be very popular. A 212HP six that's
only an inch longer than the EJ-25 four and a hundred pounds
heavier.

---
David Parrish

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David A. Ricker P. Eng.
DARTEC Engineering Inc.
Fall River, Nova Scotia
Canada

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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by David M Parrish
On 17 Jan 2001, at 22:20, David Ricker wrote:
look at this.....). Remember the equation: F=MA Force = Mass x
Acceleration, that you might have run into at school? Newtons first
which is related to the velocity squared and the mass of the
piston/rod. That is to say Energy=(MV^2)/2. The Energy here is the
kinetic energy of the piston/rod (Mass) that must be dissipated every
I seem to remember something about those...

Actually, I've wanted to do the force calculations, but I've never had
the weight values for the piston/rings/rod.
side) and an average speed of a generous 45 miles an hour over the
lifetime of the car then you will have driven for about 2200 hours,
about the TBO for an aircraft engine. The auto engine starts to look
The harder you work an engine, the shorter it lives, probably
exponetially. But even assuming a TBO of 500 hours, (And I'd say
it'll be much more than that.) they'd still be cheaper to fix or
replace. Plus, how many hours a year do most homebuilders put
on their planes anyway?

---
David Parrish

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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by David M Parrish
On 17 Jan 2001, at 22:33, Legeorgen@cs.com wrote:
Hey Dave, could you repeat that first part again, in English?
Mmm. Which part?

---
David Parrish

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Re; Engine choices

Posted: Fri Feb 17, 2012 8:39 pm
by AGT
I started this discussion to answer one simple question. Will the Suburu
engine, or the Northwest-Aero LS-1 engine for that matter, be as reliable as
a Lycoming. Simple question, right? Won't someone just say yes, or no?

Seriously, the responses have been very informative and I thank everyone
that contributed. The only true way to tell if the auto conversions are as
reliable as aircraft engines is to get 50 years of experience in the field.
Can't wait that long, so I quess I'll have to absorb all of this info and
make a decision. The sad thing is that I'm pretty sure the airframe will be
ready for an engine long before I can afford to buy one.

Mike

-----Original Message-----
From: Legeorgen@cs.com [mailto:Legeorgen@cs.com]
Sent: Wednesday, January 17, 2001 6:33 PM
To: murphy-rebel@dcsol.com
Subject: Re: Re; Engine choices


Hey Dave, could you repeat that first part again, in English?

Bruce 357R
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