Preheating engines: Airplane engines versus auto engines

"Mike Spera" wrote in message
...


I've been more cautious about rapid heating up of engines since I
unfortunately split the engine block of my Jaguar XJ6 4.2 litre that I
conclude was caused by immediate rapid driving from -5c being late for an
appointment. Guess that expensive incident will always stay in my mind...


My guess would be that the very cold temps caused the block to split due
to the coolant freezing over night. If it was -5C when you started it,
chances are it was much colder at some point in the evening.

Common in the upper Midwestern US was to see 70's era cars blow out freeze
plugs and/or crack blocks by running no (or too weak) antifreeze. A cold
start and immediate run up to high speed should not cause catastrophic
failure of a block. Being a Jag, it may have had a badly cast block since
new. Their QC ain't the best.

Good Luck,
Mike

Mike, the coolant was at the correct winter dilution so I don't think
freezing was a contributory factor. More likely sloppy engineering standards
which similarly and sadly led to the downfall of the UK's motorcycle
industry, I know I owned many UK produced bikes. At least those industries
didn't manufacture aero engines.
Cheers,
Mike

More likely sloppy engineering standards
which similarly and sadly led to the downfall of the UK's motorcycle
industry,

A slight aside: that situation is the end point of all socialized
societies... Go along to get along, and all that...


denny

On Wed, 19 Dec 2007 12:21:28 -0500, "Peter R."
wrote:

This time of year here in the Northeast US I always preheat my Bonanza's
IO520 engine with a Tanis heater and an insulated cowling/prop cover as it
sits in an unheated t-hangar. The result is that the oil temperature at
startup is around 105 degrees F, even if the outside air temperature is as
low as -15 degrees F.

Monday night I arrived at my t-hangar to discover that at some point during
the day the line person accidentally pulled out the plug connecting the Tanis
heater to the small extension cord I use to extend the plug to the outside of
the cowling cover, so the aircraft had not been preheating. Outside and
inside temperatures were both a cold 25 degrees F.

Given any other day, I would have plugged the aircraft back in and scrapped
the flight but in this case I had an Angel Flight patient waiting in another
city for my arrival and I was already late. Thus I made the painful decision
to start up the aircraft and allow it to low idle until the oil heated
thoroughly. A small consolation is that the engine had been recently filled
with fresh Exxon Elite oil. To my relief the aircraft started right up.

I know what I did has negative long term repercussions on my engine's health


Ahhhh...How do you "know" one cold start is going to have long term,
negative effects?

I normally preheat mine and when flying a lot the preheater was always
on with the cowl double wrapped. No condensation and worked great.

OTOH I have gone out on days that were really cold, not 25 degrees and
if I could get it to start I'd go flying without worrying about it.

I think you'll find that an engine that has set a long time and is
really cold takes a while to get oil to the cam. Every thing else gets
oiled just fine.

I'd not be overly concerned about a few cold starts as long as the
engine is given time enough to circulate warm oil.

In the Bo you'll know if it wasn't hot enough as the oil will congeal
in the oil cooler and the prop governor will let you know right away!
:-))

and I have already derived a tool to lock the two cords and prevent this
accidental unplugging from happening again. However, this leads me to
question the differences between aircraft engines and auto engines:

Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?

Nearly all the cars we've had in recent years have gone between 100
and 200 thousand miles. None gave engine problems, none were
preheated, and all stayed outside, or in an unheated garage. The
engines stood up far better than the bodies did.

Roger (K8RI)

On Wed, 19 Dec 2007 12:21:28 -0500, "Peter R."

Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures?

A) Automobiles have the advantage of 50+ years of research and innovation.
When did you last see a magneto ignition on a car? GA aircraft, however..

B) Ditto automobile oil. When I lived in the Twin Cities, Mobil 1 oil at
-25C was astonishing; you can spun over as if it was 35 degrees warmer.

C) Cars get used daily by most/many folks.

D) We're a nation of impatient, who GAF? people who'll sooner
buy a new car anyhow..


[ps: I did plug in my car when it got REALLY cold..]
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A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Mon, 24 Dec 2007 04:47:22 +0000 (UTC), David Lesher
wrote:


On Wed, 19 Dec 2007 12:21:28 -0500, "Peter R."

Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures?

A) Automobiles have the advantage of 50+ years of research and innovation.
When did you last see a magneto ignition on a car? GA aircraft, however..

aircraft have the same period of innovation but the developments have
been for a different aim. longevity. once the designs reached their
light weight optimum many aspects have stayed fixed.
an engine running for long periods at the same rpm has what sort of
need for vacuum advance? ...for instance.
it does have a need to be able to continue to run in spite of
electrical failure and a magneto and gravity feed do that for many
designs quite adequately. simplicity removes failure points due to
complexity. failures can kill you, simplicity keeps you alive.

aircraft have a higher risk of being struck by lightning. how much of
the high tech auto technology can survive a lightning strike?

I must admit that the dead hand of certification needs to be phased
out if there is any prospect of innovation again.
the current cosworth formula1 engines deliver 950hp at 20,000rpm from
an engine package smaller in capacity than an O-200.
I wouldnt mind a little bit more bleed through of the technology into
aviation.



B) Ditto automobile oil. When I lived in the Twin Cities, Mobil 1 oil at
-25C was astonishing; you can spun over as if it was 35 degrees warmer.

C) Cars get used daily by most/many folks.

D) We're a nation of impatient, who GAF? people who'll sooner
buy a new car anyhow..

ahhh but that is the actual reason for the technical inovation behind
the automobile. it self perpetuates the sale of new cars.
functionally a T model ford would get you around as well as any modern
car. the expectations driven by technology wouldnt allow you to be
seen dead in one so you go out and buy a new high tech car capable of
200mph and a standing quarter in 5 seconds ...so that you can drive it
in peak hour stop start traffic all the while dreaming of a circuit at
brands hatch.
cunning buggers arent they :-)

aircraft have the same period of innovation but the developments have
been for a different aim. longevity. once the designs reached their
light weight optimum many aspects have stayed fixed.
an engine running for long periods at the same rpm has what sort of
need for vacuum advance? ...for instance.
it does have a need to be able to continue to run in spite of
electrical failure and a magneto and gravity feed do that for many
designs quite adequately. simplicity removes failure points due to
complexity. failures can kill you, simplicity keeps you alive.



The thing that inhibits aircraft engine development appears to be simple
economics. With the HUGE certification and liability hurdles, there
simply are not enough potential sales to offset this economic mountain.
Auto engines can afford to fail in use because the consequences are
generally much less severe (you coast to a stop on the side of the
road). If the proposed auto innovation passes its early tests, the
market potential is generally large enough to make financial sense to go
ahead and put the thing in production.

The litigation blood suckers just about DARE anyone to attempt to
introduce any changes to the airplane market. The idiotic public puts up
with this nonsense and cheers on the suing family as they battle the
"big, bad corporation" who harmed their poor, defenseless family with
their "defective" product.

Airplane owners have a split personality as far as I can tell by reading
these forums. We cry "foul" when some idiot jury awards millions of
dollars in damages for an airplane mishap. But pilots are the first in
line to blame anyone in sight when it happens to them.

Curious lot.

Be Safe,
Mike

Stealth Pilot writes:

A) Automobiles have the advantage of 50+ years of research and innovation.
When did you last see a magneto ignition on a car? GA aircraft, however..

aircraft have the same period of innovation but the developments have
been for a different aim. longevity. once the designs reached their
light weight optimum many aspects have stayed fixed.

I respectfully disagree. There are many things we've learned from which
GA aircraft could benefit: automotive, electronic, metallurgical, human
factors.

That they don't is likely due to a "coffin corner" of low volumes, and
high overhead {including but not limited to regulatory burden..}.

Do I think aircraft engines could benefit from closed loop fuel
systems [ie fuel injection/FADEC]? Yep. Do I think such can survive
lightning? Yep. The Big Boys and the military aircraft do now; I recall
that thunderstorm research fighter at NASA-LaRC with the dozens of
thunderbolts stencils. Ditto TV/FM transmitters, who unlike the aircraft,
ARE a direct sink for the lightning. It takes some design but nothing
earthshaking.

But even small stuff, such as integral voltage regulators [inside
alternators] does not seem to come to pass.

an engine running for long periods at the same rpm has what sort of
need for vacuum advance? ...for instance.

Suppose a computerized fuel injection system offered oh, say 7% better
fuel consumption and 20% better TBO; would that be worth it? Look at the
MPG and engine life of a 1950's car and one from the last 5 years.

D) We're a nation of impatient, who GAF? people who'll sooner
buy a new car anyhow..

ahhh but that is the actual reason for the technical inovation behind
the automobile. it self perpetuates the sale of new cars.

Perhaps, but the outcome is better cars. Until the Japanese invasion,
Detroit built crap, at multiple levels: engineering, manufacturing,
QC. The dope-slap they got took years to wake them up, but it and
regulatory burdens [1] have given the customer a vehicle that's far far
better than what [s]he could buy 40 years ago. I wish the GA industry
could say the same.


1: The MPG/smog ones forced them to give up on carbs. How could anyone
ever have improved on a Rochester Quadrajet for example -- why, it's a
marval of simplicity exceeded only by the 6.02E23 parts found in a
Model 28 Teletype, right?]
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Dec 24, 2:42 am, Stealth Pilot
I must admit that the dead hand of certification needs to be phased
out if there is any prospect of innovation again.
the current cosworth formula1 engines deliver 950hp at 20,000rpm from
an engine package smaller in capacity than an O-200.

I doubt such a formula 1 engine would have better power to weight
ratio if you add the weight of the reduction gear to get the prop tip
speed below supersonic. I also doubt it can match the BSFC of a
O-200.

People often claim the auto engines are so much better. I'd like to
see an automobile gasoline engine that has 1. better BSFC than an
IO-550 at its 75% rated power and 2. better power to weight ratio
including the weight of the reduction gear to drive a propeller.

http://www.prime-mover.org/Engines/G.../article2.html has a lot
of good info.

On Dec 30, 5:56*pm, M wrote:
On Dec 24, 2:42 am, Stealth Pilot

I must admit that the dead hand of certification needs to be phased
out if there is any prospect of innovation again.
the current cosworth *formula1 engines deliver 950hp at 20,000rpm from
an engine package smaller in capacity than an O-200.

I doubt such a formula 1 engine would have better power to weight
ratio if you add the weight of the reduction gear to get the prop tip
speed below supersonic. *I also doubt it can match the BSFC of a
O-200.

People often claim the auto engines are so much better. *I'd like to
see an automobile gasoline engine that has 1. better BSFC than an
IO-550 at its 75% rated power and 2. better power to weight ratio
including the weight of the reduction gear to drive a propeller.

http://www.prime-mover.org/Engines/G...ticle2.htmlhas a lot
of good info.

Deal,,,, Come on out to Jackson Hole Wy and I will demonstrate an auto
engine that will prove both of your questions wrong.

Ben Haas
www.haaspowerair.com