Pearl Harbor Defense

In article ,
Gernot Hassenpflug writes:
"Peter" == Peter Stickney writes:

Peter Actually, it's fairly easy to see why - The Imperial
Peter Japanese Navy was only so large - they didn't have enough
Peter ships to be everywhere in the Pacific at once. /../

Peter /../ They could fly htier land-based bombers from their
Peter forward based in Indochina and Formosa, but they'd arrive
Peter without fighter escorts. The same, of course, would apply
Peter to any sea-borne invasions force - no fighter cover, and
Peter they'd be sitting ducks in the target area.

Peter /../ One of the most closely held secrets if the IJN was
Peter the unprecedented range of the A6M (Year Zero)
Peter fighter. /../

Peter Much has been made of teh Zero's maneuverability as the key
Peter to its success early in the war. /../

Sorry, but that's not true AFAIK: the fact that it came as a
surprise to some of the Allies is not the same as the IJN keeping
it a strict secret. The IJN never considered it secret, using it
in China. Chennault wrote of this fighter in 1940 and 1941, and
the Chinese certainly knew of this successor to the Type 96
'Claude'.

The existance of the Zero wasn't a secret - the fact that the Japanese
had built a single-engine fighter that could fly from Taipei to Manila
and back was. That was certainly not apparent to anybody, and the IJN
wasn't advertising that fact.

A short range fighter with extremely high performance certainly wasn't
unexpected - consider teh case of the Curtiss CW-21 "Demon" - a
lightweight short-ranged interceptor that exceeded the A6M in climb
and agility. The KNIL had a bunch of them in Java. Without the
ability to be warned in time to get off the ground and into position,
it didn't do them a bit of good.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

Peter Stickney wrote:

In article ,
Gernot Hassenpflug writes:
"Peter" == Peter Stickney writes:

Peter Actually, it's fairly easy to see why - The Imperial
Peter Japanese Navy was only so large - they didn't have enough
Peter ships to be everywhere in the Pacific at once. /../

Peter /../ They could fly htier land-based bombers from their
Peter forward based in Indochina and Formosa, but they'd arrive
Peter without fighter escorts. The same, of course, would apply
Peter to any sea-borne invasions force - no fighter cover, and
Peter they'd be sitting ducks in the target area.

Peter /../ One of the most closely held secrets if the IJN was
Peter the unprecedented range of the A6M (Year Zero)
Peter fighter. /../

Peter Much has been made of teh Zero's maneuverability as the key
Peter to its success early in the war. /../

Sorry, but that's not true AFAIK: the fact that it came as a
surprise to some of the Allies is not the same as the IJN keeping
it a strict secret. The IJN never considered it secret, using it
in China. Chennault wrote of this fighter in 1940 and 1941, and
the Chinese certainly knew of this successor to the Type 96
'Claude'.

The existance of the Zero wasn't a secret - the fact that the Japanese
had built a single-engine fighter that could fly from Taipei to Manila
and back was. That was certainly not apparent to anybody, and the IJN
wasn't advertising that fact.

One reason was that the Japanese were unaware that they had the capability
until sometime in 1941. Clark and Iba were over 450nm from the closest
Formosan bases, Manila was 500nm away. They'd never made attacks at such
ranges in China, and they were flying over land there, where navigation was
much easier. They'd originally planned to use three small carriers (the big
ones were going to PH), but that was inconvenient as they were slow and
unable to operate sufficient numbers of a/c (only 75 vs. the 250 or so Zeros
they had assembled on Formosa and believed to be necessary). So in 1941,
they started to see just how much they could safely stretch the fuel economy
of the Zero, individually and then in larger groups. Ten hour missions
became routine, then 11 and eventually they were able to stay in the air for
12. Okumiya describes this in "Zero!", with average fuel consumption
dropping to 21 gal./hr. and Saburo Sakai holding the record at only 18
gal./hr.

Guy

From: Guy Alcala

in 1941,
they started to see just how much they could safely stretch the fuel economy
of the Zero, individually and then in larger groups. Ten hour missions
became routine, then 11 and eventually they were able to stay in the air for
12. Okumiya describes this in "Zero!", with average fuel consumption
dropping to 21 gal./hr. and Saburo Sakai holding the record at only 18
gal./hr.

Interesting. The Wright R-2600 engine burned about 75gph at 60 percent power.
Any details on how the Japanese achieved such frugal fuel consumption figures?
What was "normal" fuel consumption for the Zero?



Chris Mark

In article ,
ost (Chris Mark) wrote:

From: Guy Alcala

in 1941,
they started to see just how much they could safely stretch the fuel economy
of the Zero, individually and then in larger groups. Ten hour missions
became routine, then 11 and eventually they were able to stay in the air for
12. Okumiya describes this in "Zero!", with average fuel consumption
dropping to 21 gal./hr. and Saburo Sakai holding the record at only 18
gal./hr.

Interesting. The Wright R-2600 engine burned about 75gph at 60 percent
power.
Any details on how the Japanese achieved such frugal fuel consumption
figures?
What was "normal" fuel consumption for the Zero?



Chris Mark


They achieved thos numbers by cutting back to 20%-30% power and
aggressive leaning. Lindbergh taught the same concepts to USAAF P-38
pilots -- this technique is part of what enabled the Yamamoto shootdown.
The P-38s were operating way outside their expected normal combat radius.

In article ,
Orval Fairbairn writes:
In article ,
ost (Chris Mark) wrote:

From: Guy Alcala

in 1941,
they started to see just how much they could safely stretch the fuel economy
of the Zero, individually and then in larger groups. Ten hour missions
became routine, then 11 and eventually they were able to stay in the air for
12. Okumiya describes this in "Zero!", with average fuel consumption
dropping to 21 gal./hr. and Saburo Sakai holding the record at only 18
gal./hr.

Interesting. The Wright R-2600 engine burned about 75gph at 60 percent
power.
Any details on how the Japanese achieved such frugal fuel consumption
figures?
What was "normal" fuel consumption for the Zero?



Chris Mark


They achieved thos numbers by cutting back to 20%-30% power and
aggressive leaning. Lindbergh taught the same concepts to USAAF P-38
pilots -- this technique is part of what enabled the Yamamoto shootdown.
The P-38s were operating way outside their expected normal combat radius.

Y'know, that's been mentioned any number of times about Lindberg's
trip to the Pacific. But I have some doubts about it.
The Carbs used on the later model P-38s were Bendix-Stromberg PD 12
pressure carbs. IIRC, These didn't have manual adjustment - you had
settings of "Full Rich", Auto-Rich", "Auto-Lean", and "Idle Cutoff".
you couldn't manually lean the engines.

The secret to a low fuel burn is low RPM/High BMEP. To get this, you
need to crank the prop to the desired cruise RPM (Usually Full Decrease or
thereabouts, set the throttle to the maximum setting that maintains
that RPM, and pull the mixture back to Auto-Lean. If you've chosen
the proper cruise altitude, you'll be chugging along at the minumum
drag IAS (Speed for best climb), and what determines your endurance
will be whether the relief tube's plugged.
I suspect that that's wht Lindy really taught them.

It's not a great condition to be in if you're bounced, however - you
can't just shove teh throttle forward & go. A Big recip can be
remarkably delicate at times, and just shoving the throttle forward at
low revs with a lean mixture is asking it to come apart. To spool
things up, you've got to do the hand-jive, shoving teh mixture to Full
Rich first, the prop to Full Increase, and then you can bring up the
power with the throttle. I can see somebody who's concerned about
being bounced keeping the mixture up in the AUto-Rich range and just
fiddling with the revs (Prop) and Manifold Pressure (Throttle).

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

Peter Stickney wrote:

In article ,
Orval Fairbairn writes:
In article ,
ost (Chris Mark) wrote:

From: Guy Alcala

in 1941,
they started to see just how much they could safely stretch the fuel economy
of the Zero, individually and then in larger groups. Ten hour missions
became routine, then 11 and eventually they were able to stay in the air for
12. Okumiya describes this in "Zero!", with average fuel consumption
dropping to 21 gal./hr. and Saburo Sakai holding the record at only 18
gal./hr.

Interesting. The Wright R-2600 engine burned about 75gph at 60 percent
power.
Any details on how the Japanese achieved such frugal fuel consumption
figures?
What was "normal" fuel consumption for the Zero?



Chris Mark


They achieved thos numbers by cutting back to 20%-30% power and
aggressive leaning. Lindbergh taught the same concepts to USAAF P-38
pilots -- this technique is part of what enabled the Yamamoto shootdown.
The P-38s were operating way outside their expected normal combat radius.

Y'know, that's been mentioned any number of times about Lindberg's
trip to the Pacific. But I have some doubts about it.
The Carbs used on the later model P-38s were Bendix-Stromberg PD 12
pressure carbs. IIRC, These didn't have manual adjustment - you had
settings of "Full Rich", Auto-Rich", "Auto-Lean", and "Idle Cutoff".
you couldn't manually lean the engines.

The secret to a low fuel burn is low RPM/High BMEP. To get this, you
need to crank the prop to the desired cruise RPM (Usually Full Decrease or
thereabouts, set the throttle to the maximum setting that maintains
that RPM, and pull the mixture back to Auto-Lean. If you've chosen
the proper cruise altitude, you'll be chugging along at the minumum
drag IAS (Speed for best climb), and what determines your endurance
will be whether the relief tube's plugged.
I suspect that that's wht Lindy really taught them.

Exactly right. They'd been cruising in auto-rich, low MP/high rpm. He told them to
put it in auto-lean, pull the prop back to 1,800 rpm and then advance the throttle
until they got 180mph IAS (they'd been cruising at higher speeds).

It's not a great condition to be in if you're bounced, however - you
can't just shove teh throttle forward & go. A Big recip can be
remarkably delicate at times, and just shoving the throttle forward at
low revs with a lean mixture is asking it to come apart. To spool
things up, you've got to do the hand-jive, shoving teh mixture to Full
Rich first, the prop to Full Increase, and then you can bring up the
power with the throttle. I can see somebody who's concerned about
being bounced keeping the mixture up in the AUto-Rich range and just
fiddling with the revs (Prop) and Manifold Pressure (Throttle).

The advantage of the late-war Pacific was that most of the time you were flying over
uninhabited areas or the sea, so really didn't need to worry about getting bounced
except in the vicinity of airfields. The Japanese lack of fuel also played a part.
The details are in Lindbergh's wartime journal, but IIRR the increased radii guarantees
he made to Kenney, or maybe it was Whitehead, included going to auto rich and (IIRC)
combat cruise speed in the combat zone, which I think he defined as 100 miles both in
and out, plus combat allowance, etc. The crews didn't necessarily believe him the
first couple of missions, but when they noticed he was returning to base with 100-200
gallons more fuel than they while flying the same missions, they paid attention.

Guy

On Thu, 23 Sep 2004 14:51:08 -0400, (Peter
Stickney) wrote:

If you've chosen
the proper cruise altitude, you'll be chugging along at the minumum
drag IAS (Speed for best climb), and what determines your endurance
will be whether the relief tube's plugged.
I suspect that that's wht Lindy really taught them.

I don't know if this is relevant, but when Glen Edwards flew from
Goose Bay in Canada to Bluie West One in Greenland, he remarked how
uncomfortable it was, flying at the edge of a stall with his nose high
and his tail low.

all the best -- Dan Ford
email: (put Cubdriver in subject line)

Warbird's Forum www.warbirdforum.com
Piper Cub Forum www.pipercubforum.com
Viva Bush! www.vivabush.org

In article ,
Cub Driver writes:
On Thu, 23 Sep 2004 14:51:08 -0400, (Peter
Stickney) wrote:

If you've chosen
the proper cruise altitude, you'll be chugging along at the minumum
drag IAS (Speed for best climb), and what determines your endurance
will be whether the relief tube's plugged.
I suspect that that's wht Lindy really taught them.

I don't know if this is relevant, but when Glen Edwards flew from
Goose Bay in Canada to Bluie West One in Greenland, he remarked how
uncomfortable it was, flying at the edge of a stall with his nose high
and his tail low.

Quite relevant, I'd say. Ernie Gann wrote about it in "Fate is the
Hunter", as well. Apparently it went against every gut feeling they
had. Even today, you'll find people who'll tell you that running an
engine "oversquare" (More Manifold pressure in Inches Hg than RPM in
100s - say, 30" vs 3000R) is Absolutely Evil. (Again, you'll only
get there with a controllable pitch prop - with a fixed pitch, set for
takeoff power at sea level, you'll generally run out of torque defore
you;ll reach the RPM redline at any sort of altitude). While its true
that yo can overboost an engine if you aren't careful, thw Handbook
numbers are solid - the Manufacturer can't get them past the FAA
without proving them.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

In article ,
ost (Chris Mark) writes:
From: Guy Alcala

in 1941,
they started to see just how much they could safely stretch the fuel economy
of the Zero, individually and then in larger groups. Ten hour missions
became routine, then 11 and eventually they were able to stay in the air for
12. Okumiya describes this in "Zero!", with average fuel consumption
dropping to 21 gal./hr. and Saburo Sakai holding the record at only 18
gal./hr.

Interesting. The Wright R-2600 engine burned about 75gph at 60 percent power.
Any details on how the Japanese achieved such frugal fuel consumption figures?
What was "normal" fuel consumption for the Zero?

They did it the classical way - Minimum RPM, Maximum Manifold Pressure
to maintain that RPM, as lean a mixture as the engine can stand, and
flying at the altitude where, with those conditions, they could
maintain the minimum drag spot on the airplane's drag curve. (Probably
around 15,000', in a Zero, maybe a bit lower.)
You can turn in some really impressive fuel burn numbers that way.
The low RPM means that the total volume of fuel/air mixture per unit
of time is as small as it can get. The High Manifold Pressure means
that you're getting the most out of that small volume.

Note that you can't do this unless you've got a fully controllable or
Constant Speed prop.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

Chris Mark wrote:

From: Guy Alcala

in 1941,
they started to see just how much they could safely stretch the fuel economy
of the Zero, individually and then in larger groups. Ten hour missions
became routine, then 11 and eventually they were able to stay in the air for
12. Okumiya describes this in "Zero!", with average fuel consumption
dropping to 21 gal./hr. and Saburo Sakai holding the record at only 18
gal./hr.

Interesting. The Wright R-2600 engine burned about 75gph at 60 percent power.
Any details on how the Japanese achieved such frugal fuel consumption figures?
What was "normal" fuel consumption for the Zero?

I have a vague memory of reading 30-35gal./hr. somewhere, but don't hold me to
it. The A6M2 had the Sakae 12 engine, which was only rated at 950 hp or so. When
they got the A6M3 Model 32 in the Solomons, which had the more powerful Sakae 21
engine of 1,130 hp (and slightly less fuel) plus clipped tips, they found that its
range was inadequate to make it from Rabaul to Guadalcanal and back (it was
pushing it for the A6M2), which IIRR was something like 550 sm one way. They
built intermediate strips down the Solomons (Buin, etc) so that it could get there
and back, and put the A6M3 Model 22 with increased internal fuel and the full
wingspan (non-folding, like the first production model, the A6M2 Model 11) into
production for land use.

The USN found that for carrier operations, overall they could plan on R-2600s
burning 45-50 gal./hr average per sortie (which includes lots of low speed loiter
for landing and ASW patrol) depending on whether it was in an Avenger or a
Helldiver, while the R-2800 in the Hellcat burned about 75 or so (same landing
loiter, CAP loiter). The exact mix of sortie types flown would affect the
average, but as far as planning for carrier AVGAS replenishment needs, that gave
them good numbers.

Guy