Standards for H.P. corr. factors ??

[jerry wass]

To what standards are today's(and/or yesterdays) A/C engines corrected to???

I find the older SAE J607--60°F---29.92" Hg 0% humidity
SAE J1349--77°F 29.234"Hg 0%
DIN 68°F 29.92
JIS 77°F 29.234 0%
?? J1995 77°F 29.53 0%
(29.53"Hg = 100KPa )


My guess is that it is the older J607--,but I'd like a 2nd opinion.

Thanks a Whole bunch--Jerry

[Peter Dohm]

"Jerry Wass" > wrote in message
. net...
> To what standards are today's(and/or yesterdays) A/C engines corrected
to???
>
> I find the older SAE J607--60°F---29.92" Hg 0% humidity
> SAE J1349--77°F 29.234"Hg 0%
> DIN 68°F 29.92
> JIS 77°F 29.234 0%
> ?? J1995 77°F 29.53 0%
> (29.53"Hg = 100KPa )
>
>
> My guess is that it is the older J607--,but I'd like a 2nd opinion.
>
> Thanks a Whole bunch--Jerry

To the best of my knowledge and recollection, they use International
Standard Atmosphere (ISA) and part of the definition, including 59°F and
29.92"Hg, can be seen at: http://www.pilotsweb.com/wx/w_sense.htm#isa
However, little is stated in the article with regard to humidity except that
the atmosphere can contain a lot of water--which displaces the other gasses.
The figure of 5% was shown somewhere one the page, but was not tied to a
particular temperature.

I was also able to find a an article in Wikipedia:
http://en.wikipedia.org/wiki/Standard_temperature_and_pressure which
includes a table, about a third of the way down the page. The table
suggests that ISA is based upon 0% humidity--which would not be achieved in
real life.

I do know that the effect of humidity, especially at high temperatures, is
considerable on the takeoff roll and dramatic on climb performance. IIRC,
the reduction in horsepower due to humidity can be around 10%, while the
same amount of humidity would have only a 1% reduction in air density with
regard to the wings.

Considering that climb performance is entirely based on reserve power, above
that required to fly the aircraft, the result can be downright scary!

I have seen articles on the subject, including real numbers usefull for
pre-takeoff planning, but can not find any at the moment.

Peter

[jerry wass]

Peter Dohm wrote:
> "Jerry Wass" > wrote in message
> . net...
>> To what standards are today's(and/or yesterdays) A/C engines corrected
> to???
>> I find the older SAE J607--60°F---29.92" Hg 0% humidity
>> SAE J1349--77°F 29.234"Hg 0%
>> DIN 68°F 29.92
>> JIS 77°F 29.234 0%
>> ?? J1995 77°F 29.53 0%
>> (29.53"Hg = 100KPa )
>>
>>
>> My guess is that it is the older J607--,but I'd like a 2nd opinion.
>>
>> Thanks a Whole bunch--Jerry
>
> To the best of my knowledge and recollection, they use International
> Standard Atmosphere (ISA) and part of the definition, including 59°F and
> 29.92"Hg, can be seen at: http://www.pilotsweb.com/wx/w_sense.htm#isa
> However, little is stated in the article with regard to humidity except that
> the atmosphere can contain a lot of water--which displaces the other gasses.
> The figure of 5% was shown somewhere one the page, but was not tied to a
> particular temperature.
>
> I was also able to find a an article in Wikipedia:
> http://en.wikipedia.org/wiki/Standard_temperature_and_pressure which
> includes a table, about a third of the way down the page. The table
> suggests that ISA is based upon 0% humidity--which would not be achieved in
> real life.
>
> I do know that the effect of humidity, especially at high temperatures, is
> considerable on the takeoff roll and dramatic on climb performance. IIRC,
> the reduction in horsepower due to humidity can be around 10%, while the
> same amount of humidity would have only a 1% reduction in air density with
> regard to the wings.
>
> Considering that climb performance is entirely based on reserve power, above
> that required to fly the aircraft, the result can be downright scary!
>
> I have seen articles on the subject, including real numbers usefull for
> pre-takeoff planning, but can not find any at the moment.
>
> Peter
>
> Thanks, Peter I found the above at --> wahiduddin.net/calc/cf.htm -

-But it seemed to be race car engine oriented--I recently rebuilt my
airplane engine & can measure all the parameters, but didn't know what
system of specs to use in order to compare it with the A/C engines in
use today--Jerry

[Charles Vincent]

Jerry Wass wrote:
> To what standards are today's(and/or yesterdays) A/C engines corrected
> to???
>
> I find the older SAE J607--60°F---29.92" Hg 0% humidity
> SAE J1349--77°F 29.234"Hg 0%
> DIN 68°F 29.92
> JIS 77°F 29.234 0%
> ?? J1995 77°F 29.53 0%
> (29.53"Hg = 100KPa )
>
>
> My guess is that it is the older J607--,but I'd like a 2nd opinion.
>
> Thanks a Whole bunch--Jerry

I sincerely doubt it was the J607 standard used to rate the engines
since if you actually read the J607 standard you will see that it
clearly states that it was developed for basically lawnmower engines(<
50 ci displacement and < 20hp) You will also see that it allows for only
a ten percent correction to be applied. A real hoot when you see it
applied to a 500hp supercharged engine. However your question seems to
be what is the standard day used for calculations, rather than the
calculations applied, so I will say I believe the FAA uses standard day,
standard atmosphere at sea level with zero humidity calculated by the
formulas defined in the US Standard Atmosphere 1976 standard(Temperature
= 15°C, specific humidity = 0.00 kg H2O/kg dry air, and pressure =
101325 Pa). I also believe that this standard is largely in agreement
with the international standard at near sea level altitudes that you are
concerned with.

As far as what standard was in effect at the time a particular engine
was certified, I can't tell you. There are versions of the US Standard
Atmosphere going back to 1958, and I do not know what correction factors
were applied.

The FAA engine certification tests are more rigorous than the typical
dyno run and require an endurance test that includes the following regimes:

(1) A 30-hour run consisting of alternate periods of five minutes at
takeoff power and speed, and five minutes at maximum best economy
cruising power or maximum recommended cruising power.

(2) A 20-hour run consisting of alternate periods of 1½ hours at maximum
continuous power and speed, and ½ hour at 75 percent maximum continuous
power and 91 percent maximum continuous speed.

(3) A 20-hour run consisting of alternate periods of 1½ hours at maximum
continuous power and speed, and ½ hour at 70 percent maximum continuous
power and 89 percent maximum continuous speed.

(4) A 20-hour run consisting of alternate periods of 1½ hours at maximum
continuous power and speed, and ½ hour at 65 percent maximum continuous
power and 87 percent maximum continuous speed.

(5) A 20-hour run consisting of alternate periods of 1½ hours at maximum
continuous power and speed, and ½ hour at 60 percent maximum continuous
power and 84.5 percent maximum continuous speed.

(6) A 20-hour run consisting of alternate periods of 1½ hours at maximum
continuous power and speed, and ½ hour at 50 percent maximum continuous
power and 79.5 percent maximum continuous speed.

(7) A 20-hour run consisting of alternate periods of 2½ hours at maximum
continuous power and speed, and 2½ hours at maximum best economy
cruising power or at maximum recommended cruising power

I will bet that many of the un-certified engines being marketed out
there couldn't finish the endurance test without swallowing an exhaust
valve.


Charles

[jerry wass]

Charles Vincent wrote:
> Jerry Wass wrote:
>> To what standards are today's(and/or yesterdays) A/C engines corrected
>> to???
>>
>> I find the older SAE J607--60°F---29.92" Hg 0% humidity
>> SAE J1349--77°F 29.234"Hg 0%
>> DIN 68°F 29.92
>> JIS 77°F 29.234 0%
>> ?? J1995 77°F 29.53 0%
>> (29.53"Hg = 100KPa )
>>
>>
>> My guess is that it is the older J607--,but I'd like a 2nd opinion.
>>
>> Thanks a Whole bunch--Jerry
>
> I sincerely doubt it was the J607 standard used to rate the engines
> since if you actually read the J607 standard you will see that it
> clearly states that it was developed for basically lawnmower engines(<
> 50 ci displacement and < 20hp) You will also see that it allows for only
> a ten percent correction to be applied. A real hoot when you see it
> applied to a 500hp supercharged engine. However your question seems to
> be what is the standard day used for calculations, rather than the
> calculations applied, so I will say I believe the FAA uses standard day,
> standard atmosphere at sea level with zero humidity calculated by the
> formulas defined in the US Standard Atmosphere 1976 standard(Temperature
> = 15°C, specific humidity = 0.00 kg H2O/kg dry air, and pressure =
> 101325 Pa). I also believe that this standard is largely in agreement
> with the international standard at near sea level altitudes that you are
> concerned with.
>
> As far as what standard was in effect at the time a particular engine
> was certified, I can't tell you. There are versions of the US Standard
> Atmosphere going back to 1958, and I do not know what correction factors
> were applied.
>
> The FAA engine certification tests are more rigorous than the typical
> dyno run and require an endurance test that includes the following regimes:
>
> (1) A 30-hour run consisting of alternate periods of five minutes at
> takeoff power and speed, and five minutes at maximum best economy
> cruising power or maximum recommended cruising power.
>
> (2) A 20-hour run consisting of alternate periods of 1½ hours at maximum
> continuous power and speed, and ½ hour at 75 percent maximum continuous
> power and 91 percent maximum continuous speed.
>
> (3) A 20-hour run consisting of alternate periods of 1½ hours at maximum
> continuous power and speed, and ½ hour at 70 percent maximum continuous
> power and 89 percent maximum continuous speed.
>
> (4) A 20-hour run consisting of alternate periods of 1½ hours at maximum
> continuous power and speed, and ½ hour at 65 percent maximum continuous
> power and 87 percent maximum continuous speed.
>
> (5) A 20-hour run consisting of alternate periods of 1½ hours at maximum
> continuous power and speed, and ½ hour at 60 percent maximum continuous
> power and 84.5 percent maximum continuous speed.
>
> (6) A 20-hour run consisting of alternate periods of 1½ hours at maximum
> continuous power and speed, and ½ hour at 50 percent maximum continuous
> power and 79.5 percent maximum continuous speed.
>
> (7) A 20-hour run consisting of alternate periods of 2½ hours at maximum
> continuous power and speed, and 2½ hours at maximum best economy
> cruising power or at maximum recommended cruising power
>
> I will bet that many of the un-certified engines being marketed out
> there couldn't finish the endurance test without swallowing an exhaust
> valve.
>
>
> Charles

Thanks, Charles, I'm inclined to agree with you--the 59°F temp rings a
bell in my memory.

[Morgans[_2_]]

"Charles Vincent" > wrote

> I will bet that many of the un-certified engines being marketed out there
> couldn't finish the endurance test without swallowing an exhaust valve.

Time for someone to trot out the GM stress test for new engines.

It makes the FAA tests look like a walk in the park.

Anyone got a copy of that handy?
--
Jim in NC

[Charles Vincent]

Morgans wrote:
> "Charles Vincent" > wrote
>
>> I will bet that many of the un-certified engines being marketed out there
>> couldn't finish the endurance test without swallowing an exhaust valve.
>
> Time for someone to trot out the GM stress test for new engines.
>
> It makes the FAA tests look like a walk in the park.
>
> Anyone got a copy of that handy?

I have the GM Automotive Test Code for 1967 (the FAA test regime was
codified in 1964). It specifies a two hundred hour durability test,
whereas the FAA is one hundred and fifty hour endurance test for
reciprocating non supercharged engines or reciprocating single speed
supercharged engines. Two speed supercharged and helicopter engines are
longer as I recall. The GM test code requires the engine to complete a
200 hour test schedule "without major failure". The engine is cycled
between peak torque rpm and peak hp rpm +200 rpm (max rpm not to exceed
4600)on five minute intervals. Every five and a half cycles, speed to
be reduced to idle from max test speed by closing throttle for two
minutes, after which engine speed is brought up to maximum upshift speed
within 10 seconds +/- 5 seconds, the speed is then reduced again to the
peak torque rpm and the normal cycle is continued again. The engine is
inspected every twenty five hours for cranking compression, blowby, belt
tension and ignition timing. I don't have the current testing codes for
GM, and since GM isn't selling an uncertified engine for aircraft use, I
don't know the relevance and doesn't effect my belief that many of the
un-certified engines being marketed out there couldn't finish the
endurance test without swallowing an exhaust valve.

Charles

[Rich S.[_1_]]

"Morgans" > wrote in message
...
>
>
> Time for someone to trot out the GM stress test for new engines.
>
> It makes the FAA tests look like a walk in the park.
>
> Anyone got a copy of that handy?

No, but I remember one test for the Chevy 350 V-8. They were trying to run
the test in the greater Los Angeles area and couldn't pass. It turned out
the intake air was more polluted than the specs for the exhaust emissions.

They had to move the laboratory out to some dry lake east of L.A. to run the
test. It passed. The exhaust was more pollution-free than the air in L.A.

Urban legend? I dunno, but I flew over L.A. in the 60's and had less than a
mile visibility on a clear day.

Rich S.

[Peter Dohm]

"Charles Vincent" > wrote in message
. ..
> Morgans wrote:
> > "Charles Vincent" > wrote
> >
> >> I will bet that many of the un-certified engines being marketed out
there
> >> couldn't finish the endurance test without swallowing an exhaust valve.
> >
> > Time for someone to trot out the GM stress test for new engines.
> >
> > It makes the FAA tests look like a walk in the park.
> >
> > Anyone got a copy of that handy?
>
> I have the GM Automotive Test Code for 1967 (the FAA test regime was
> codified in 1964). It specifies a two hundred hour durability test,
> whereas the FAA is one hundred and fifty hour endurance test for
> reciprocating non supercharged engines or reciprocating single speed
> supercharged engines. Two speed supercharged and helicopter engines are
> longer as I recall. The GM test code requires the engine to complete a
> 200 hour test schedule "without major failure". The engine is cycled
> between peak torque rpm and peak hp rpm +200 rpm (max rpm not to exceed
> 4600)on five minute intervals. Every five and a half cycles, speed to
> be reduced to idle from max test speed by closing throttle for two
> minutes, after which engine speed is brought up to maximum upshift speed
> within 10 seconds +/- 5 seconds, the speed is then reduced again to the
> peak torque rpm and the normal cycle is continued again. The engine is
> inspected every twenty five hours for cranking compression, blowby, belt
> tension and ignition timing. I don't have the current testing codes for
> GM, and since GM isn't selling an uncertified engine for aircraft use, I
> don't know the relevance and doesn't effect my belief that many of the
> un-certified engines being marketed out there couldn't finish the
> endurance test without swallowing an exhaust valve.
>
> Charles
>
>
I don't know of anything that is necessarily specific to any one automotive
brand, but a test procedure from some time in the 1990s has been posted to
this NG a couple of times. As of this time, I can't find it; either because
I can't remember the file name or because it died with an older computer.

To the best of my recollection, the more recent engine testing includes a
rather long run, possibly 100 total hours, at 100% power. Interestingly,
the actual purpose is to verify the effectiveness and durability of the
torsion dampener. Failure of the torsion dampener will cause a failure of
the crankshaft and/or drive train--as will its absence or incorrect
calibration--which should be of considerable interest on this NG.

I suspect that the cycling test between maximum torque and maximum power is
also primarily a verification of harmonic dampening; but that is only a
presumption on my part--with the discalimer that I am not an automotive
engineer.

In addition, there was mention of a temperature cycling test in which the
engine is repeatedly run at full throttle until normal temperature is
reached, shut down and chilled to below freezing, then started and run
immediately at full throttle until normal temperature is reached, etc. The
purpose was stated to be verification of the head gaskets and related
clamping force--especially on engines that were all or partly aluminum.

There is also a cycling test including an automatic transmission, in which
the engine repeatedly runs up through the gears and then back down--as
though a driver accelerated through the gears in drive with the accelerator
to the floor, then pulled the lever into low and coasted back
down--repeating the process over and over. According to the account which
was given, an engine will usually outlast multiple transmissions. Obvoiusly
the test has value in predicting warranty costs, but the exact purpose is a
mystery to me.

Further disclaimer: All of this is from memory and the true original source
is unknown, as is the brand of engine(s) involved.

Peter

[Dave S]

Charles Vincent wrote:

>
> I will bet that many of the un-certified engines being marketed out
> there couldn't finish the endurance test without swallowing an exhaust
> valve.
>
>
> Charles

Mine could. Simply because it doesn't have valves.

On a side note that IS interesting about the certification requirements
and the endurance required.

I wonder how many "certified engines" are requiring rebuild at the
completion of a full regime used during the certification process.

Dave
Mazda rotary goin in a velocity SE

[Charles Vincent]

Peter Dohm wrote:

> I don't know of anything that is necessarily specific to any one automotive
> brand, but a test procedure from some time in the 1990s has been posted to
> this NG a couple of times. As of this time, I can't find it; either because
> I can't remember the file name or because it died with an older computer.
>
There is an article from Contact magazine that has been posted here
before. It states that GM runs at max hp rpm with max load for 265
hours as one test and does the cyclic test I described for 400 hours,
along with the thermal testing you mentioned. However, I have not seen
the actual formal test regime, whereas I have a copy of the 1967 test
regime. In the end, it still doesn;t matter as GM is not to my
knowledge selling reciprocating aircraft engines certified or otherwise
and I have not seen any evidence many of the uncertified engines for
sale are testing their engines at this level.

Charles

[Morgans[_2_]]

"Charles Vincent" < wrote

> In the end, it still doesn;t matter as GM is not to my knowledge selling
> reciprocating aircraft engines certified or otherwise and I have not seen
> any evidence many of the uncertified engines for sale are testing their
> engines at this level.

I guess the point that we were making, is that although GM is not selling
uncertified engines for airplanes, a number of them do find their ways into
experimental airplanes, thus the reaction about the reliability of auto
engines.

Interestingly, it is most always not the core auto engine that experiences
failure when an auto engine conversion has problems, but the prop speed
reducer, or fuel system, or non original fuel system, or whatever else has
been added or re-engineered by the experimenter.

I hope this sheds light on why your comments got such a swift and
enthusiastic rebuttal by some here. It sounded as if you were condemning
those that used auto engines for airplanes, as a unsatisfactory, not as
tough engine as what is made as a certified engine.

After all of the major metallurgical crankshaft problems that some of the
certified engines have had as of late, it is hard to accept that just
because it is certified, it is completely reliable.
--
Jim in NC

[Peter Dohm]

"Morgans" > wrote in message
...
>
> "Charles Vincent" < wrote
>
> > In the end, it still doesn;t matter as GM is not to my knowledge selling
> > reciprocating aircraft engines certified or otherwise and I have not
seen
> > any evidence many of the uncertified engines for sale are testing their
> > engines at this level.
>
> I guess the point that we were making, is that although GM is not selling
> uncertified engines for airplanes, a number of them do find their ways
into
> experimental airplanes, thus the reaction about the reliability of auto
> engines.
>
> Interestingly, it is most always not the core auto engine that experiences
> failure when an auto engine conversion has problems, but the prop speed
> reducer, or fuel system, or non original fuel system, or whatever else has
> been added or re-engineered by the experimenter.
>
> I hope this sheds light on why your comments got such a swift and
> enthusiastic rebuttal by some here. It sounded as if you were condemning
> those that used auto engines for airplanes, as a unsatisfactory, not as
> tough engine as what is made as a certified engine.
>
> After all of the major metallurgical crankshaft problems that some of the
> certified engines have had as of late, it is hard to accept that just
> because it is certified, it is completely reliable.
> --
> Jim in NC
>
>
I interpreted the comment as pertaining to uncertified engines, or engined
certified to a different standard, originally manufactured and sold for
aircraft use.

Peter

[Peter Dohm]

"Charles Vincent" > wrote in message
et...
> Peter Dohm wrote:
>
> > I don't know of anything that is necessarily specific to any one
automotive
> > brand, but a test procedure from some time in the 1990s has been posted
to
> > this NG a couple of times. As of this time, I can't find it; either
because
> > I can't remember the file name or because it died with an older
computer.
> >
> There is an article from Contact magazine that has been posted here
> before. It states that GM runs at max hp rpm with max load for 265
> hours as one test and does the cyclic test I described for 400 hours,
> along with the thermal testing you mentioned. However, I have not seen
> the actual formal test regime, whereas I have a copy of the 1967 test
> regime. In the end, it still doesn;t matter as GM is not to my
> knowledge selling reciprocating aircraft engines certified or otherwise
> and I have not seen any evidence many of the uncertified engines for
> sale are testing their engines at this level.
>
> Charles

I believe that you have summed it up rather well.

I remain undecided whether I might or might not adapt an automotive engine
for aircraft use, but I would cdertainly avoid any of the changes which
would negate the laboratory and field testing which had already been done.
Changing or removing flywheels, driving from the accessory end, and changing
cams and timing are all high on that list--as is nearly anything else that
does not let the engine "believe" that it is still doing what it always did.
If that makes it too heavy, then it is simply the wrong engine for the job.

Peter

[Charles Vincent]

Morgans wrote:
> "Charles Vincent" < wrote
>
>> In the end, it still doesn;t matter as GM is not to my knowledge selling
>> reciprocating aircraft engines certified or otherwise and I have not seen
>> any evidence many of the uncertified engines for sale are testing their
>> engines at this level.
>
> I guess the point that we were making, is that although GM is not selling
> uncertified engines for airplanes, a number of them do find their ways into
> experimental airplanes, thus the reaction about the reliability of auto
> engines.

Automotive engines today are exceptionally reliable. No where did I
impugn automotive engines. It is also obvious that all readers are not
clear on the use of the adjective "many". Many does not mean all or
even imply a majority, it at most implies more than "several".

> Interestingly, it is most always not the core auto engine that experiences
> failure when an auto engine conversion has problems, but the prop speed
> reducer, or fuel system, or non original fuel system, or whatever else has
> been added or re-engineered by the experimenter.

What the heck does that have to do with it? "Why, its the best most
reliable 200hp airplane engine you can buy, unless you insist on hanging
a prop on it -- have you considered building an ornithoper?" If it is
not reliable when configured for use in an airplane, it is not a
reliable airplane engine. The FAA endurance test requires "a propeller
ordinarily used on a similar engine" be installed, it is also required
for the vibration survey, which is another specified test. The FAA
tests and certification has specific requirements of the fuel,
lubrication and ignition system with aviation necessities in mind. I
believe the reduction unit would be part of the equipment tested, as the
type sheets list the geared and ungeared varieties as separate engines.

>
> I hope this sheds light on why your comments got such a swift and
> enthusiastic rebuttal by some here. It sounded as if you were condemning
> those that used auto engines for airplanes, as a unsatisfactory, not as
> tough engine as what is made as a certified engine.

It may have been enthusiatic, but it was not a rebuttal. I opined that
many (not all) un-certified engines being marketed (not built in
backyards from automotive sources) would be unable to complete the
endurance test. People responded with evidence that automotive
manufacturers did endurance testing of automotive engines configured
with accessories required for automotive use (i.e. transmissions etc)
which has nothing to do with my statement.

I am not a certified engine bigot and I believe experimental aviation
should be experimental ( I also believe homebuilts should be homebuilt
as well) I was more specifically aiming at the vendors targeting the
experimental market with uncertified engines that make outlandish claims
regarding reliability, fuel burn and most especially power. The first
two tests --

(1) A 30-hour run consisting of alternate periods of five minutes at
takeoff power and speed, and five minutes at maximum best economy
cruising power or maximum recommended cruising power.

(2) A 20-hour run consisting of alternate periods of 1½ hours at maximum
continuous power and speed, and ½ hour at 75 percent maximum continuous
power and 91 percent maximum continuous speed.

--- would highlight the fact that just camming and carbing an engine to
produce 100hp on the dyno isn't going to be enough to get it through
thirty hours of five minute 100hp bursts with a five minute cooling
period at what, 75HP?. The second test is just going to further
highlight any deficiencies in cooling. There is often a vast difference
between dyno results and useful power.

> After all of the major metallurgical crankshaft problems that some of the
> certified engines have had as of late, it is hard to accept that just
> because it is certified, it is completely reliable.

No one said it was, but do you honestly think an honest comparison of
certified engine installations with uncertified engine installations on
a reliability basis is going to make certified engines look bad? You
would have to compare incidents per hour of operation for all certified
engines vs incidents per hour of operation for all uncertified engines.
The data I doubt exists and the data that is there is probably
not proportionate i.e. certified installations are more likely to be
reported than uncertified. As I understand it the Lycoming debacle
affected 3000-5000 engines and resulted from a combination of a change
in alloy used for the crank and the jobber forging the cranks not
holding to the forging temps required. Small details that resulted in
the crank not being up to the job of carrying prop loads at power. So
do you think uncertified engines are more immune to this than certified?
As immune? So how does some relatively low volume uncertified engine
company with parts sourced from everywhere from chinese made bubble pack
hot rod stuff, to custom machined assemblies going to track things at
that level? Particularly when most of the parts where never intended
for aviation and the part vendor is continually trying to optimize his
costs for his intended market? And your backyard assembler/builder?
Even though I am not really talking about automotive manufacturers, I
will point out that the number of auto recalls and TSB's issued on a
monthly basis is not insignificant even with their endurance testing.
Anyway, this is not intended as a diatribe against un certified engines.
I think they are great. I was really just addressing the original
poster's question on the standard day used for certified engines. I
assumed he was going to be using that information to compare his
favorite certified engine to some recently dyno'd uncertified variant
being marketed. My point was just that as I said before in this post,
there is often a vast difference between dyno results and useful power
and an endurance test ala FAA is more useful than a dyno run.

Charles

[Morgans[_2_]]

Wow, big post. I'll just hit a couple points to respond to. ;-)

> Automotive engines today are exceptionally reliable. No where did I
> impugn automotive engines. It is also obvious that all readers are not
> clear on the use of the adjective "many". Many does not mean all or even
> imply a majority, it at most implies more than "several".

I may have jumped in without fully understanding the response to the OP.
That never happens around here, does it? <g>
>
>> Interestingly, it is most always not the core auto engine that
>> experiences failure when an auto engine conversion has problems, but the
>> prop speed reducer, or fuel system, or non original fuel system, or
>> whatever else has been added or re-engineered by the experimenter.
>
> What the heck does that have to do with it?

I was making a point that the experimenter that builds his ow PSRU does so
at much risk, unless it is really well engineered. There are comercial
units out there that have very good reliability records. People get into
trouble when they try to improve on the standard conversion, usually. You
are correct though, the engine and PSRU and any other additions that make
the whole package is what really counts in the end.

> I am not a certified engine bigot and I believe experimental aviation
> should be experimental ( I also believe homebuilts should be homebuilt as
> well) I was more specifically aiming at the vendors targeting the
> experimental market with uncertified engines that make outlandish claims
> regarding reliability, fuel burn and most especially power.

I get a kick out of the 100 HP VW's, especially.
--
Jim in NC

[[email protected]]

> I get a kick out of the 100 HP VW's, especially.
> --
> Jim in NC
-------------------------------------------------------------------------------------------

Even 80hp should have you rolling on the floor :-)

After waving the magical 80hp flag at a tent-full of round-eyed
admirers the next kerchief out of his sleeve is usually "3.3 gph"
followed by a round of patting himself on the back in routine worth of
a French circus. Are we great or what?

Truth is, if you know engines and want some serious fun, get a bunch
of real engine guys together and show them the Aero-vee assembly
video. I swear to God it's the funniest thing I've seen in years.
Seriously. Most guys assume it's a put-on. When they realize it's
being sold as a 'expert advice' their reactions range from blowing
beer out their nose to simply sitting there in stunned amazement.

-R.S.Hoover

[Barnyard BOb]

Morgans wrote:

>"Charles Vincent" > wrote
>
>> I will bet that many of the un-certified engines being marketed out there
>> couldn't finish the endurance test without swallowing an exhaust valve.
>
>Time for someone to trot out the GM stress test for new engines.
>
>It makes the FAA tests look like a walk in the park.
>
>Anyone got a copy of that handy?
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Morgans, no need.

You're outclassed no matter what you wave at the crowd. :-)

I am sooooo glad that I have no dogs in this hunt.....

YET!


- Barnyard BOb -

[Morgans[_2_]]

"Barnyard BOb" > wrote >
> Morgans, no need.
>
> You're outclassed no matter what you wave at the crowd. :-)
>
> I am sooooo glad that I have no dogs in this hunt.....
>
> YET!

I know, I know. Keep flying those ancient tractor engines, and be quiet!
<g>

I had not sighted you around, for a while, so I thought it would be safe to
throw out the conversion engine testing bit.

Next time, give me a 3 day warning before you pop in, so I know whether to
post stuff like that, or to wait until you are gone! ;-)
--
Jim in NC

[Peter Dohm]

"Morgans" > wrote in message
...
>
> "Charles Vincent" > wrote
>
> > I will bet that many of the un-certified engines being marketed out
there
> > couldn't finish the endurance test without swallowing an exhaust valve.
>
> Time for someone to trot out the GM stress test for new engines.
>
> It makes the FAA tests look like a walk in the park.
>
> Anyone got a copy of that handy?
> --
> Jim in NC
>
>
IIRC, the one who used to post that article was Corky Scott and it has been
quite some time since I have observed any posts from him. OTOH, I have
never been sure which manufacturer's stress test that may have been. A
frequent contributor to another NG, who was retired from one of the other
automobile companies, occasionally wrote in the same style as the article
that I recall; but that style may very well be generic to the industry.

However, I am glad that you brought the subject back up; because there are a
couple of points which I neglected to make in an earlier post in a branch of
this thread.

1) The certification test for aircraft engines really does apear to be
directly related to the actual use and performance of aircraft engines, as
installed, using real propellers and an acceptable simulation of real
aircraft cooling systems--with all of the efficiencies and inefficiencies
which all of that might imply.

2) The automotive engine stress tests could very well be exactly what the
name implies--Stress Tests. In other words, they may well be very carefully
designed tests to predict certian common warranty problems on new engine
models--as used in automobiles where they commonly operate between idle and
20% power, with occasional bursts of full power and occasional demands for
maximum power from cold engines. Based on that possibility, it would be
very usefull to know the engine coolant outlet *and* inlet temperatures and
flow rate as well as the oil outlet *and* inlet temperatures and flow rate
during the sustained high power run. (Remember that they have chillers on
line which probably have far more capability than the engines under test.)
There are a few other things I would like to know, specifically for any
engine which I might consider for conversion, such as any additional steady
speeds which might have been tested; but those temperatures and flow rates
would tell whether the engine showed any promise when using any plausible
cooling system in an aircraft.

There are still several automotive engines that I believe have a lot of
promise, and I would really enjoy such a project. However, it would save a
lot of effort if a few more data points happened to be published.

Peter

[Peter Dohm]

> wrote in message
oups.com...
>
> > I get a kick out of the 100 HP VW's, especially.
> > --
> > Jim in NC
> --------------------------------------------------------------------------
-----------------
>
> Even 80hp should have you rolling on the floor :-)
>
> After waving the magical 80hp flag at a tent-full of round-eyed
> admirers the next kerchief out of his sleeve is usually "3.3 gph"
> followed by a round of patting himself on the back in routine worth of
> a French circus. Are we great or what?
>
> Truth is, if you know engines and want some serious fun, get a bunch
> of real engine guys together and show them the Aero-vee assembly
> video. I swear to God it's the funniest thing I've seen in years.
> Seriously. Most guys assume it's a put-on. When they realize it's
> being sold as a 'expert advice' their reactions range from blowing
> beer out their nose to simply sitting there in stunned amazement.
>
> -R.S.Hoover
>
I am much more of a theoretical engine guy than a real engine guy, and IIRC
it took a little effort on your part to set me straight on the thermal
limits of the VW heads; so I have faith that you will help to clear up
whatever misconceptions I may have on this as well.

With that disclaimer...

it seems to me that there is an additional way to look at the 80HP VW issue:
80HP from 130CID at 3450RPM is plausible in standard air; for a time limited
by cooling, etc. However, my limited knowledge of propellers suggests that
either the RPM or the manifold pressure must change quite soon--even with an
engine that could handle the load continuously--and I am not convinced that
it is achievable more than momentarily

Soooo.... the 3.3GPH may be the real key to the puzzle. Given a fixed
pitch prop, there is no way for this all to happen at the most efficient RPM
and MP. Therefore, 3.3GPH means to me that cruise is less than 43HP; since
about 13 horsepower hours per gallon is the best it can get under the
circumstances and with the type of engine and fuel system in use.

And then... dividing 43 by 0.75 it becomes clear that, when the subsequent
round table discussion is included, this is at least a 3-Beer video.

Peter
(Also starting to wonder about that little jewel from down under... )

[Peter Dohm]

> >
> > > I get a kick out of the 100 HP VW's, especially.
> > > --
> > > Jim in NC
>
> --------------------------------------------------------------------------
> -----------------
> >
> > Even 80hp should have you rolling on the floor :-)
> >
> > After waving the magical 80hp flag at a tent-full of round-eyed
> > admirers the next kerchief out of his sleeve is usually "3.3 gph"
> > followed by a round of patting himself on the back in routine worth of
> > a French circus. Are we great or what?
> >
> > Truth is, if you know engines and want some serious fun, get a bunch
> > of real engine guys together and show them the Aero-vee assembly
> > video. I swear to God it's the funniest thing I've seen in years.
> > Seriously. Most guys assume it's a put-on. When they realize it's
> > being sold as a 'expert advice' their reactions range from blowing
> > beer out their nose to simply sitting there in stunned amazement.
> >
> > -R.S.Hoover
> >
> I am much more of a theoretical engine guy than a real engine guy, and
IIRC
> it took a little effort on your part to set me straight on the thermal
> limits of the VW heads; so I have faith that you will help to clear up
> whatever misconceptions I may have on this as well.
>
> With that disclaimer...
>
> it seems to me that there is an additional way to look at the 80HP VW
issue:
> 80HP from 130CID at 3450RPM is plausible in standard air; for a time
limited
> by cooling, etc. However, my limited knowledge of propellers suggests
that
> either the RPM or the manifold pressure must change quite soon--even with
an
> engine that could handle the load continuously--and I am not convinced
that
> it is achievable more than momentarily
>
> Soooo.... the 3.3GPH may be the real key to the puzzle. Given a fixed
> pitch prop, there is no way for this all to happen at the most efficient
RPM
> and MP. Therefore, 3.3GPH means to me that cruise is less than 43HP;
since
> about 13 horsepower hours per gallon is the best it can get under the
> circumstances and with the type of engine and fuel system in use.
>
> And then... dividing 43 by 0.75 it becomes clear that, when the
subsequent
> round table discussion is included, this is at least a 3-Beer video.
>
> Peter
> (Also starting to wonder about that little jewel from down under... )
>
>
It seems that I got so wrapped up in my writing that I forgot just how close
that cruising power might be to the practical maximum continuous....

Peter :-(

[[email protected]]

On Jul 7, 1:39 pm, "Peter Dohm" > wrote:

> I am much more of a theoretical engine guy than a real engine guy, and IIRC
> it took a little effort on your part to set me straight on the thermal
> limits of the VW heads; so I have faith that you will help to clear up
> whatever misconceptions I may have on this as well.
> ----------------------------------------------------------------------------------------

Dear Peter,

The magnesium crankcase is referred to as aluminum, old, used parts
are referred to as 'factory new,' bearing shells are installed atop a
splatter of spray-paint... But the humor has more to do with the
overall incompetence of the video rather than the fallacious
statements. The video is larded with hilarious Mechanical Sight-Gags
that can't be described without losing the essence of the humor; you
NEED to see it for yourself.

The Beer Fountain erupted when, upon completing some mundane task, the
assembler puts thumb to forefinger and gives the camera a close-up
'okay' for all the deaf-mutes in the audience. Doing it once was
funny but the second time even Old Stoneface cracked up: 'This guy
makes Dubya look like a Whiz Kid.'

Giiven the nature of the medium -- the ability to re-shoot a take
until they got it right -- it's hard to understand why they would
leave in so many scenes showing them doing things wrong. That caused
a bit of discussion, some arguing that it had to be a put-on... until
someone pointed out that they probably HAD re-shot and edited TO THE
BEST OF THEIR ABILITY. Which makes the video a ****-up of truly
monumental proportions.

Like I said, you've GOT to see it. This thing is a collector's item.

-R.S.Hoover

[Peter Dohm]

> wrote in message
oups.com...
> On Jul 7, 1:39 pm, "Peter Dohm" > wrote:
>
> > I am much more of a theoretical engine guy than a real engine guy, and
IIRC
> > it took a little effort on your part to set me straight on the thermal
> > limits of the VW heads; so I have faith that you will help to clear up
> > whatever misconceptions I may have on this as well.
>
> --------------------------------------------------------------------------
--------------
>
> Dear Peter,
>
> The magnesium crankcase is referred to as aluminum, old, used parts
> are referred to as 'factory new,' bearing shells are installed atop a
> splatter of spray-paint... But the humor has more to do with the
> overall incompetence of the video rather than the fallacious
> statements. The video is larded with hilarious Mechanical Sight-Gags
> that can't be described without losing the essence of the humor; you
> NEED to see it for yourself.
>
> The Beer Fountain erupted when, upon completing some mundane task, the
> assembler puts thumb to forefinger and gives the camera a close-up
> 'okay' for all the deaf-mutes in the audience. Doing it once was
> funny but the second time even Old Stoneface cracked up: 'This guy
> makes Dubya look like a Whiz Kid.'
>
> Giiven the nature of the medium -- the ability to re-shoot a take
> until they got it right -- it's hard to understand why they would
> leave in so many scenes showing them doing things wrong. That caused
> a bit of discussion, some arguing that it had to be a put-on... until
> someone pointed out that they probably HAD re-shot and edited TO THE
> BEST OF THEIR ABILITY. Which makes the video a ****-up of truly
> monumental proportions.
>
> Like I said, you've GOT to see it. This thing is a collector's item.
>
> -R.S.Hoover
>
The search for a copy is now under way!

Thanks,
Peter

[Morgans[_2_]]

"Peter Dohm" <> wrote

> 2) The automotive engine stress tests could very well be exactly what
> the
> name implies--Stress Tests. In other words, they may well be very
> carefully
> designed tests to predict certian common warranty problems on new engine
> models--as used in automobiles where they commonly operate between idle
> and
> 20% power, with occasional bursts of full power and occasional demands for
> maximum power from cold engines.

I remember it more as a worst case abuse test. LOTS of WOT running, some of
it for longer periods of time than certifications tests.

> Based on that possibility, it would be
> very usefull to know the engine coolant outlet *and* inlet temperatures
> and
> flow rate as well as the oil outlet *and* inlet temperatures and flow rate
> during the sustained high power run. (Remember that they have chillers on
> line which probably have far more capability than the engines under test.)
> There are a few other things I would like to know, specifically for any
> engine which I might consider for conversion, such as any additional
> steady
> speeds which might have been tested; but those temperatures and flow rates
> would tell whether the engine showed any promise when using any plausible
> cooling system in an aircraft.

Good point about flow rates and temperature.

From the guys that have used Ford and Chevy V-6's, they have not had a
problem with cooling if the system is well designed to create a good
positive air pressure. Shoot, instead of real radiators, most use two GM
air conditioner condenser radiators. It seems like cooling must not be too
hard, with those two little radiators.

The only problem stated is that they can not sit for too long, without
overheating.

I always wondered why they don't put little fans on the radiators, as is
standard for auto applications. I know, a little more weight, but if it got
me though long taxi situations at fly-ins, and big airports, that would be
weight I would be willing to carry.
--
Jim in NC

[Peter Dohm]

"Morgans" > wrote in message
...
>
> "Peter Dohm" <> wrote
>
> > 2) The automotive engine stress tests could very well be exactly what
> > the
> > name implies--Stress Tests. In other words, they may well be very
> > carefully
> > designed tests to predict certian common warranty problems on new engine
> > models--as used in automobiles where they commonly operate between idle
> > and
> > 20% power, with occasional bursts of full power and occasional demands
for
> > maximum power from cold engines.
>
> I remember it more as a worst case abuse test. LOTS of WOT running, some
of
> it for longer periods of time than certifications tests.
>
The test does include long periods of WOT, in addition to a lot more types
of extremely severe service. My point about the idle to 20% power is that
most of the engines sold will be used in automobiles with mostly very
lightly loaded operation, interspersed with bursts of acceleration onto
highways and occasional panic acceleration with cold engines. As I
understand it, the real purpose of the tests is to accelerate the possible
failures of a few critical parts, such as vibration dampers and head
gaskets, in an effort to predict and control the long term costs associated
with warranties--and especially extended warranties and service contracts
which can frequently by 7 years and 100,000 miles.

> > Based on that possibility, it would be
> > very usefull to know the engine coolant outlet *and* inlet temperatures
> > and
> > flow rate as well as the oil outlet *and* inlet temperatures and flow
rate
> > during the sustained high power run. (Remember that they have chillers
on
> > line which probably have far more capability than the engines under
test.)
> > There are a few other things I would like to know, specifically for any
> > engine which I might consider for conversion, such as any additional
> > steady
> > speeds which might have been tested; but those temperatures and flow
rates
> > would tell whether the engine showed any promise when using any
plausible
> > cooling system in an aircraft.
>
> Good point about flow rates and temperature.
>
> From the guys that have used Ford and Chevy V-6's, they have not had a
> problem with cooling if the system is well designed to create a good
> positive air pressure. Shoot, instead of real radiators, most use two GM
> air conditioner condenser radiators. It seems like cooling must not be
too
> hard, with those two little radiators.
>
> The only problem stated is that they can not sit for too long, without
> overheating.
>
It's good to hear that the cooling works reasonably well at normal power
levels--at least for the V6 engines. There are basically two cooling
problems to overcome at idle: First, there is the usual problem of
downdraft cooling in which the air must be pushed downward even though
convection wants to move it the other way--and a lot of air cooled engines
have the same problem when the installation is entirely designed around high
speed and low drag and the cooling inlets are simply too small to get the
job done at idle. The second problem is peculiar to liquid cooled engines
in which most of the coolant in the radiators is positioned lower than most
of the coolant in the engine--the water pump needs to turn fast enough to
move the coolant in a direction opposite from its natural convection. The
result is that a lot of V6 and V8 engine installations with offest reduction
drives (usually belt or chain) probably suffer from a "double wammy" in
terms of cooling difficulty at idle. OTOH, some of the inverted
installations, such as Steve Wittman's conversion for the Tailwind, which
had updraft cooling and the radiator mounted above the inverted crankcase,
should be immune from those problems--although I neglected to ask Steve
Wittman that question and have not had an opportunity to ask anyone else
with real world experience.
(He was in attedance and had the V8 Tailwind on display at SnF a number of
years ago.)

> I always wondered why they don't put little fans on the radiators, as is
> standard for auto applications. I know, a little more weight, but if it
got
> me though long taxi situations at fly-ins, and big airports, that would be
> weight I would be willing to carry.

I don't know the real reason, but fans would definitely restrict the airflow
at speed. That could be a greater penalty than the modest weight.

Peter