Quantitative Pulse and Glide

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Old 02 Feb 2011, 01:12 am   #1 (permalink)
bwilson4web
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Default Quantitative Pulse and Glide

Good testing is based upon holding as many variables constant and only
changing the one under question. Certainly it is important to document
the methodology to so others can replicate THE RESULT. Sad to say, we
get a lot of "Pulse and Glide" methodology and too little test results
where everything is kept constant except the use of "Pulse and Glide"
versus say "constant equivalent speed."

On a single day I conducted a series of runs over the same course,
both ways, only changing:

o pulse and glide
o constant speed

PROTOCOL

Pulse was handled by using "resume" on the cruise control stalk. Glide
was handled by shifting into "N". This limited the speed range to
25-42 mph due to the 23 mph lower limit of cruise control memory and
upper limit of 41 mph on hybrid mode.

Constant speed was handle by setting cruise control to the equivalent,
speed over the course of the pulse and glide protocol. Entry to the
course was at the constant speed equivalent. Exit was at a fixed
location at least six pulse and glide cycles later.

RESULTS:

constant - PnG
70 - 78
74 - 85
76 - 90
85 - 93
90 - 94
- - - - - -
79 - 88 MPG average

PnG = 11.4% improvement

So for the pleasures of changing the speed from 25 mph to 42 mph,
mileage improved 11.4%. Sad to say, I've only found one other similar
report, SAE 2009-01-1322. However, it looks like they allowed the
traction battery SOC to decrease during some of their tests. Still, we
have two documented tests comparing PnG to constant speed.

.. . . Anyone else?

Bob Wilson
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Old 02 Feb 2011, 07:42 am   #2 (permalink)
News
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Default Re: Quantitative Pulse and Glide

On 2/2/2011 2:12 AM, bwilson4web wrote:
> Pulse was handled by using "resume" on the cruise control stalk. Glide
> was handled by shifting into "N". This limited the speed range to
> 25-42 mph due to the 23 mph lower limit of cruise control memory and
> upper limit of 41 mph on hybrid mode.


With respect, what effect do you think this sort of repeated, wide speed
variation (+68% to -41%) has on surrounding drivers and traffic?
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Old 02 Feb 2011, 08:38 am   #3 (permalink)
bwilson4web
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Default Re: Quantitative Pulse and Glide

On Feb 2, 7:42*am, News <N...@Group.Post> wrote:
> On 2/2/2011 2:12 AM, bwilson4web wrote:
>
> > Pulse was handled by using "resume" on the cruise control stalk. Glide
> > was handled by shifting into "N". This limited the speed range to
> > 25-42 mph due to the 23 mph lower limit of cruise control memory and
> > upper limit of 41 mph on hybrid mode.

>
> With respect, what effect do you think this sort of repeated, wide speed
> variation (+68% to -41%) has on surrounding drivers and traffic?


I think it is nuts with other traffic around. It leads to unnecessary
tailgating at both ends of the speed range . . . depending upon the
posted maximum speed.

Both the SAE paper and my own testing confirm these should only be
done isolated from other traffic. So in my case, it was a Saturday
morning on a straight, flat road at Redstone Arsenal that connects the
river side recreational areas and the main base. If other traffic
showed up, I aborted the test by pulling on to the shoulder and
parking. After traffic cleared, I proceeded to the next start point
and set it up again. But I believe low-traffic roads and parking lots
exists that can be used for such tests and this is why I'm looking for
others who might measure their Pulse and Glide performance versus
constant speed.

Likely places to find under utilized roads and parking lots include:
sports stadiums and recreational areas at dawn or non-weekend days.
Roads near rivers are often fairly flat, especially if on flood
planes. Higher speeds can often be tested safely between 2:00 and 5:00
AM. The key is to find roadways at times they have very little traffic
and if there are multiple lanes, use the emergency "flashers" to
signal following traffic should pass.

From my standpoint, I'm interested in the physics, the engineering
aspects that let us know how much pulse and glide improves mileage.
Too often I see only one number posted:

"I got <wonderful> MPG using pulse and glide at <Y> elapsed speed."

Without the control:

"I repeated the same route at a constant <Y> speed and got <something
else> MPG."

This second statement is too often missing so no one can really tell
what pulse and glide accomplished.

Bob Wilson

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Old 02 Feb 2011, 09:26 am   #4 (permalink)
News
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Default Re: Quantitative Pulse and Glide

On 2/2/2011 9:38 AM, bwilson4web wrote:
> On Feb 2, 7:42 am, News<N...@Group.Post> wrote:
>> On 2/2/2011 2:12 AM, bwilson4web wrote:
>>
>>> Pulse was handled by using "resume" on the cruise control stalk. Glide
>>> was handled by shifting into "N". This limited the speed range to
>>> 25-42 mph due to the 23 mph lower limit of cruise control memory and
>>> upper limit of 41 mph on hybrid mode.

>>
>> With respect, what effect do you think this sort of repeated, wide speed
>> variation (+68% to -41%) has on surrounding drivers and traffic?

>
> I think it is nuts with other traffic around.


<Note to "Bruce Richmond">

> It leads to unnecessary tailgating at both ends of the speed range . . .
> depending upon the posted maximum speed.


<Note to "Bruce Richmond">

> Both the SAE paper and my own testing confirm these should only be
> done isolated from other traffic. So in my case, it was a Saturday
> morning on a straight, flat road at Redstone Arsenal that connects the
> river side recreational areas and the main base. If other traffic
> showed up, I aborted the test by pulling on to the shoulder and
> parking. After traffic cleared, I proceeded to the next start point
> and set it up again. But I believe low-traffic roads and parking lots
> exists that can be used for such tests and this is why I'm looking for
> others who might measure their Pulse and Glide performance versus
> constant speed.
>
> Likely places to find under utilized roads and parking lots include:
> sports stadiums and recreational areas at dawn or non-weekend days.
> Roads near rivers are often fairly flat, especially if on flood
> planes. Higher speeds can often be tested safely between 2:00 and 5:00
> AM. The key is to find roadways at times they have very little traffic
> and if there are multiple lanes, use the emergency "flashers" to
> signal following traffic should pass.
>
> From my standpoint, I'm interested in the physics, the engineering
> aspects that let us know how much pulse and glide improves mileage.
> Too often I see only one number posted:
>
> "I got<wonderful> MPG using pulse and glide at<Y> elapsed speed."
>
> Without the control:
>
> "I repeated the same route at a constant<Y> speed and got<something
> else> MPG."
>
> This second statement is too often missing so no one can really tell
> what pulse and glide accomplished.
>
> Bob Wilson
>


Agreed. Experimental design is important. As is limiting experiments
to the lab.
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Old 02 Feb 2011, 08:01 pm   #5 (permalink)
Elmo P. Shagnasty
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Default Re: Quantitative Pulse and Glide

In article <Hc-dnUIWs-anwtTQnZ2dnUVZ_hadnZ2d@speakeasy.net>,
News <News@Group.Post> wrote:

> On 2/2/2011 2:12 AM, bwilson4web wrote:
> > Pulse was handled by using "resume" on the cruise control stalk. Glide
> > was handled by shifting into "N". This limited the speed range to
> > 25-42 mph due to the 23 mph lower limit of cruise control memory and
> > upper limit of 41 mph on hybrid mode.

>
> With respect, what effect do you think this sort of repeated, wide speed
> variation (+68% to -41%) has on surrounding drivers and traffic?


He doesn't care.

But I bet he gets REAL cranky when the outside world doesn't cooperate
and let him play his rolling video game according to HIS rules.

It's amazing how many people think they don't have to live in the real
world.
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Old 02 Feb 2011, 11:46 pm   #6 (permalink)
Bruce Richmond
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Default Re: Quantitative Pulse and Glide

On Feb 2, 10:26*am, News <N...@Group.Post> wrote:
> On 2/2/2011 9:38 AM, bwilson4web wrote:
>
> > On Feb 2, 7:42 am, News<N...@Group.Post> *wrote:
> >> On 2/2/2011 2:12 AM, bwilson4web wrote:

>
> >>> Pulse was handled by using "resume" on the cruise control stalk. Glide
> >>> was handled by shifting into "N". This limited the speed range to
> >>> 25-42 mph due to the 23 mph lower limit of cruise control memory and
> >>> upper limit of 41 mph on hybrid mode.

>
> >> With respect, what effect do you think this sort of repeated, wide speed
> >> variation (+68% to -41%) has on surrounding drivers and traffic?

>
> > I think it is nuts with other traffic around.

>
> <Note to "Bruce Richmond">
>
> > It leads to unnecessary tailgating at both ends of the speed range . . ..
> > depending upon the posted maximum speed.

>
> <Note to "Bruce Richmond">
>


<Note to News, learn to read.>

http://groups.google.com/group/alt.a...521c684d?hl=en

"The down side is that it will annoy anyone stuck behind you when you
are doing it. I know that and make it a point not to play that game
when someone is stuck behind me."

Did you not understand the above statement?



>
>
>
> > Both the SAE paper and my own testing confirm these should only be
> > done isolated from other traffic. So in my case, it was a Saturday
> > morning on a straight, flat road at Redstone Arsenal that connects the
> > river side recreational areas and the main base. If other traffic
> > showed up, I aborted the test by pulling on to the shoulder and
> > parking. After traffic cleared, I proceeded to the next start point
> > and set it up again. But I believe low-traffic roads and parking lots
> > exists that can be used for such tests and this is why I'm looking for
> > others who might measure their Pulse and Glide performance versus
> > constant speed.

>
> > Likely places to find under utilized roads and parking lots include:
> > sports stadiums and recreational areas at dawn or non-weekend days.
> > Roads near rivers are often fairly flat, especially if on flood
> > planes. Higher speeds can often be tested safely between 2:00 and 5:00
> > AM. The key is to find roadways at times they have very little traffic
> > and if there are multiple lanes, use the emergency "flashers" to
> > signal following traffic should pass.

>
> > *From my standpoint, I'm interested in the physics, the engineering
> > aspects that let us know how much pulse and glide improves mileage.
> > Too often I see only one number posted:

>
> > "I got<wonderful> *MPG using pulse and glide at<Y> *elapsed speed."

>
> > Without the control:

>
> > "I repeated the same route at a constant<Y> *speed and got<something
> > else> *MPG."

>
> > This second statement is too often missing so no one can really tell
> > what pulse and glide accomplished.

>
> > Bob Wilson

>
> Agreed. *Experimental design is important. *As is limiting experiments
> to the lab.- Hide quoted text -
>
> - Show quoted text -


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Old 03 Feb 2011, 01:28 am   #7 (permalink)
News
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Default Re: Quantitative Pulse and Glide

On 2/3/2011 12:46 AM, Bruce Richmond wrote:
> On Feb 2, 10:26 am, News<N...@Group.Post> wrote:
>> On 2/2/2011 9:38 AM, bwilson4web wrote:
>>
>>> On Feb 2, 7:42 am, News<N...@Group.Post> wrote:
>>>> On 2/2/2011 2:12 AM, bwilson4web wrote:

>>
>>>>> Pulse was handled by using "resume" on the cruise control stalk. Glide
>>>>> was handled by shifting into "N". This limited the speed range to
>>>>> 25-42 mph due to the 23 mph lower limit of cruise control memory and
>>>>> upper limit of 41 mph on hybrid mode.

>>
>>>> With respect, what effect do you think this sort of repeated, wide speed
>>>> variation (+68% to -41%) has on surrounding drivers and traffic?

>>
>>> I think it is nuts with other traffic around.

>>
>> <Note to "Bruce Richmond">
>>
>>> It leads to unnecessary tailgating at both ends of the speed range . . .
>>> depending upon the posted maximum speed.

>>
>> <Note to "Bruce Richmond">
>>

>
> <Note to News, learn to read.>
>
> http://groups.google.com/group/alt.a...521c684d?hl=en
>
> "The down side is that it will annoy anyone stuck behind you when you
> are doing it. I know that and make it a point not to play that game
> when someone is stuck behind me."
>
> Did you not understand the above statement?
>
>
>
>>
>>
>>
>>> Both the SAE paper and my own testing confirm these should only be
>>> done isolated from other traffic. So in my case, it was a Saturday
>>> morning on a straight, flat road at Redstone Arsenal that connects the
>>> river side recreational areas and the main base. If other traffic
>>> showed up, I aborted the test by pulling on to the shoulder and
>>> parking. After traffic cleared, I proceeded to the next start point
>>> and set it up again. But I believe low-traffic roads and parking lots
>>> exists that can be used for such tests and this is why I'm looking for
>>> others who might measure their Pulse and Glide performance versus
>>> constant speed.

>>
>>> Likely places to find under utilized roads and parking lots include:
>>> sports stadiums and recreational areas at dawn or non-weekend days.
>>> Roads near rivers are often fairly flat, especially if on flood
>>> planes. Higher speeds can often be tested safely between 2:00 and 5:00
>>> AM. The key is to find roadways at times they have very little traffic
>>> and if there are multiple lanes, use the emergency "flashers" to
>>> signal following traffic should pass.

>>
>>> From my standpoint, I'm interested in the physics, the engineering
>>> aspects that let us know how much pulse and glide improves mileage.
>>> Too often I see only one number posted:

>>
>>> "I got<wonderful> MPG using pulse and glide at<Y> elapsed speed."

>>
>>> Without the control:

>>
>>> "I repeated the same route at a constant<Y> speed and got<something
>>> else> MPG."

>>
>>> This second statement is too often missing so no one can really tell
>>> what pulse and glide accomplished.

>>
>>> Bob Wilson

>>
>> Agreed. Experimental design is important. As is limiting experiments
>> to the lab.- Hide quoted text -
>>
>> - Show quoted text -

>



You backpedal well.
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Old 03 Feb 2011, 02:44 am   #8 (permalink)
bwilson4web
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Default Re: Quantitative Pulse and Glide

On Feb 3, 1:28*am, News <N...@Group.name> wrote:
> . . .


I'm less interested in what people do in traffic as there are plenty
of 'bad examples' out there. For example, this morning there was an
upscale sedan doing between 40-45 mph on a cross-town, 50 mph, divided
road followed by a service van towing a trailer that was rocking back
and forth. Traffic was backed up behind them and I took advantage to
follow the van. So I got the mileage advantage by exploiting the poor
judgement of two other vehicles . . . sweet. I parked at work with
just over 50 MPG indicated and the temperature was just under 40 F.

What I still don't see posted is anyone else's pulse-and-glide
performance over the same route, same average speed versus the
constant speed equivalent. This test can be conducted late at night,
say after midnight, if nothing else to answer the question:

"What mileage improvement does PnG provide over the equivalent,
constant speed?"

As for the safety aspects, there are enough poor drivers we don't
really need to 'flog our own.' But if someone thinks PnG is so great,
answer the question. Give some quantitative numbers:

a) minimum speed - glide end
b) maximum speed - pulse
c) equivalent constant speed
d) MPG in PnG
e) MPG at constant speed

Several years ago, some folks spent a week in Oklahoma driving section
lines in a Honda Insight endurance test. Using their mileage log,
they'd been driving at a constant speed equivalent of 16-18 mph. This
also corresponds to the maximum speed range of a Prius (and probably
quite a few other hybrids.)

If PnG boosts the equivalent constant speed mileage say by a factor of
two:

20 MPG @40 mph - constant speed
40 MPG @40 mph, 5 to 75 mph - pulse and glide

(40-20)/20 = 100% improvement

This would be a game changer but I never measured more than 12%
improvement. In contrast, the SAE paper claimed some curious numbers:

89.1 MPG @25 mph - constant speed (0.0% SOC decrease)
128.9 MPG @25 mph, 20 to 30 mph - pulse and glide (0.5% SOC decrease)
(128.9 - 89.1)/89.1 = 44.7% improvement

81.0 MPG @35 mph - constant speed (0.0% SOC decrease)
151.5 MPG @35 mph, 30 to 40 mph - pulse and glide (1.5% SOC decrease)
(151.5 - 81.0)/81.0 = 87% improvement

80.9 MPG @35 mph - constant speed (0.0% SOC decrease)
99.9 MPG @35 mph, 30 to 40 mph - pulse and glide (0.5% SOC decrease)
(99.9 - 80.9)/80.9 = 23.5% improvement

What I suspect is many lay reports about how great Pulse and Glide
performs may be just the discharge of the traction battery providing
the additional energy that is not counted in the total energy
picture.

So the challenge remains, the question remains:

What is the payback of Pulse and Glide versus a constant speed?

BTW, a route will hills changes the physics. Climbing can move the
engine into power regions that are fuel inefficient. In reality, any
test should be against a constant ICE power setting and let speed
follow load. But more of this advanced topic later ... if we can stop
bashing poor driving including going the minimum posted speed limit on
an Interstate.

Bob Wilson
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Old 03 Feb 2011, 06:18 am   #9 (permalink)
Bruce Richmond
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Default Re: Quantitative Pulse and Glide

On Feb 3, 2:28*am, News <N...@Group.name> wrote:
> On 2/3/2011 12:46 AM, Bruce Richmond wrote:
>
>
>
>
>
> > On Feb 2, 10:26 am, News<N...@Group.Post> *wrote:
> >> On 2/2/2011 9:38 AM, bwilson4web wrote:

>
> >>> On Feb 2, 7:42 am, News<N...@Group.Post> * *wrote:
> >>>> On 2/2/2011 2:12 AM, bwilson4web wrote:

>
> >>>>> Pulse was handled by using "resume" on the cruise control stalk. Glide
> >>>>> was handled by shifting into "N". This limited the speed range to
> >>>>> 25-42 mph due to the 23 mph lower limit of cruise control memory and
> >>>>> upper limit of 41 mph on hybrid mode.

>
> >>>> With respect, what effect do you think this sort of repeated, wide speed
> >>>> variation (+68% to -41%) has on surrounding drivers and traffic?

>
> >>> I think it is nuts with other traffic around.

>
> >> <Note to "Bruce Richmond">

>
> >>> It leads to unnecessary tailgating at both ends of the speed range . .. .
> >>> depending upon the posted maximum speed.

>
> >> <Note to "Bruce Richmond">

>
> > <Note to News, learn to read.>

>
> >http://groups.google.com/group/alt.a...sg/b5b72484521...

>
> > "The down side is that it will annoy anyone stuck behind you when you
> > are doing it. *I know that and make it a point not to play that game
> > when someone is stuck behind me."

>
> > Did you not understand the above statement?

>
> >>> Both the SAE paper and my own testing confirm these should only be
> >>> done isolated from other traffic. So in my case, it was a Saturday
> >>> morning on a straight, flat road at Redstone Arsenal that connects the
> >>> river side recreational areas and the main base. If other traffic
> >>> showed up, I aborted the test by pulling on to the shoulder and
> >>> parking. After traffic cleared, I proceeded to the next start point
> >>> and set it up again. But I believe low-traffic roads and parking lots
> >>> exists that can be used for such tests and this is why I'm looking for
> >>> others who might measure their Pulse and Glide performance versus
> >>> constant speed.

>
> >>> Likely places to find under utilized roads and parking lots include:
> >>> sports stadiums and recreational areas at dawn or non-weekend days.
> >>> Roads near rivers are often fairly flat, especially if on flood
> >>> planes. Higher speeds can often be tested safely between 2:00 and 5:00
> >>> AM. The key is to find roadways at times they have very little traffic
> >>> and if there are multiple lanes, use the emergency "flashers" to
> >>> signal following traffic should pass.

>
> >>> * From my standpoint, I'm interested in the physics, the engineering
> >>> aspects that let us know how much pulse and glide improves mileage.
> >>> Too often I see only one number posted:

>
> >>> "I got<wonderful> * *MPG using pulse and glide at<Y> * *elapsed speed."

>
> >>> Without the control:

>
> >>> "I repeated the same route at a constant<Y> * *speed and got<something
> >>> else> * *MPG."

>
> >>> This second statement is too often missing so no one can really tell
> >>> what pulse and glide accomplished.

>
> >>> Bob Wilson

>
> >> Agreed. *Experimental design is important. *As is limiting experiments
> >> to the lab.- Hide quoted text -

>
> >> - Show quoted text -

>
> You backpedal well.- Hide quoted text -
>
> - Show quoted text -


Thank you for demonstrating that you don't even know what that term
means. In my first post to this thread where I mention pulse and
glide I wrote "The roads around here are mostly 2 lane, and coasting
down to 20 mph in a 35 zone with traffic behind you isn't really an
option."

http://groups.google.com/group/alt.a...2f6f497b?hl=en

So I made it clear from the begining that I didn't condone getting in
the way of others. You are a troll to keep implying that I do.
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Old 03 Feb 2011, 08:15 am   #10 (permalink)
bwilson4web
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Default Re: Quantitative Pulse and Glide

On Feb 3, 6:18*am, Bruce Richmond <bsr3...@my-deja.com> wrote:
.. . .
>
> . . . *In my first post to this thread where I mention pulse and
> glide I wrote "The roads around here are mostly 2 lane, and coasting
> down to 20 mph in a 35 zone with traffic behind you isn't really an
> option."
> . . .


All I'm interested in is a comparison of pulse and glide versus the
equivalent constant speed speed. BTW, there is one place I use 'pulse
and glide' without being a traffic hazard . . . a 'rolling warm-up.'

On cold mornings, I cut through my 25 mph posted, neighborhood streets
taking the 'back roads' to let the engine warm-up with a minimum fuel
burn:
http://hiwaay.net/~bzwilson/prius/map.jpg

The characteristics are:

17-25 mph, PnG, 'glide' in "N"
~30-35 MPG, ~1.5 miles

21 mph, constant speed
~20-22 MPG

Because I'm running parallel to the main commuting route, there is
very little traffic 'going my way.' With four cross streets leading to
the main commuting route, the vast majority of traffic turns at the
next intersection to commute to work. In those rare cases were someone
is following, it is because they are going to park at their home in
that block. But about once every four months or so, I pull over to
park at someone's house to let a following vehicle pass . . .
following traffic is very, very rare.

Coasting in "N" minimizes the fuel burned to warm-up the engine to a
rate of ~0.30 gallons per hour. There is no throttle setting that has
an equivalent, consistent, low fuel burn rate measured with my
ScanGauge. Regardless, the goal is to arrive at the commuting route
intersection when the car has warmed enough to enter "stage 4" or
hybrid mode. It is more accurate to call this a 'rolling warm-up'
because I don't use it once the engine coolant reaches 70 C.

I have a somewhat similar protocol leaving work where I can exploit
catalytic converter warm-up. There is a 30-40 second window when the
NHW11 Prius uses traction battery power and idles the engine at
~0.60-0.70 gallons per hour. By parking near the parking lot exit,
this is long enough to reach 35-40 mph before the catalytic converters
light off and normal engine warm-up begins. But at 35-40 mph, I'm
keeping up with traffic and by follow downgrades, can maximize the use
of the low-fuel burn rate, "N" during warm-up. Again, as soon as the
car reaches "stage 4" or normal hybrid mode, I'm back to normal,
constant speed mode.

BTW, in warmer mornings, I often take one of the earlier cross streets
once the engine coolant goes over 60 C. Again, this is a rolling 'warm-
up' using "N" to minimize fuel burn when rolling. In contrast, most
'pulse and glide' advocates claim the engine must be off or throttle
feathered during the glide. My scangauge indicates there is no
feathering with a lower rate of fuel burn than "N".

Bob Wilson

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