Subject: Re: Have you flown a Zero?
From: jesw@mitre.org (James Wilkins)
Date: May 14 1997
Newsgroups: rec.aviation.military

In article <01bc5f59$f0f2bfe0$4a2cc8cd@x.mb.sympatico.ca>, "x"
<kchoy@mts.net> wrote:

> I don't know of anyone who flew a Zero, but 2 things: 1)they are remaking
> them in Carmen, Manitoba, Canada and my friend who was one of the original
> Golden Eagles who flew the P51, the Spitfire and the F84 in Korea told me
> something I didn't realize--the reason why Zero was highly explosive was
> for both speed and the HERO worship to die heroically. Kevin

Jiro Horikoshi's book Eagles of Mitsubishi describes the extreme
difficulty he had with weight reduction. He had to use an unproven alloy
(7075) and reduce the strength safety factor below 1.8 in violation of
government regulations. He would have built a stronger plane if they had
let him relax the performance specs.

-- 
James Wilkins
The Mitre Corp.
Bedford, MA

Subject: Re: Have you flown a Zero?
From: jesw@mitre.org (James Wilkins)
Date: May 15 1997
Newsgroups: rec.aviation.military

In article <5ld5eo$9js@sjx-ixn5.ix.netcom.com>, erikavg@ix.netcom.com(Erik
Shilling) wrote:
> HI James Wilkins
> Hirikoshi's statement is difficult for me to accept and I'll explain
> why.

> [snip CW21 specs; comparable A6M specs are missing from Horikoshi's book]

> My question is why would the Zero with an empty weight of a little over
> 5,000 pound was built so flimsy unless it was a designe flaw, and he
> used the above excuse to save face?

> Erik Shilling.

The book reads like a Wehrmacht general's memoirs - I did all I could,
someone else was to blame. In particular the Japanese were behind the West
in engine technology and he carefully points out how each extra kilogram
of engine weight increases the wing size, the fuel tankage, the landing
gear, the fuselage structure, etc. He worked for Mitsubishi but had to go
to rival Nakajima for an adequate engine. That must have cost some face,
although he says management agreed with him. Nakajima in turn had decided
they couldn't design an aircraft that could meet the specifications. 

He also complained about the shortage of engineering talent. I wonder how
much of our success was due to millions of impoverished teenage motorheads
who entered the service able to fix almost anything. Yeager had worked in
the gas fields, for example. My dad's unit in New Guinea turned a
"wrecked" Jeep into an ice maker. 

At the end he claims that no one else has ever achieved more overall
performance from so little horsepower (not that anyone else had to).

-- 
James Wilkins
The Mitre Corp.
Bedford, MA

Subject: Re: Have you flown a Zero?
From: jesw@mitre.org (James Wilkins)
Date: May 16 1997
Newsgroups: rec.aviation.military

In article <5ld5eo$9js@sjx-ixn5.ix.netcom.com>, erikavg@ix.netcom.com(Erik
Shilling) wrote:

> Curtiss Wright, about the same time the zero was built, had built an
> intercepter call the CW-21, also know as the Demon.
> 
> This airplane's empty weight was 3150 lbs (the zero's 5200 lbs) had two
> fifties and two thirties. Had a top speed of 315 mph. (the zero's top
> speed according to Saburo Sakai was 309 mph) had a rate of Climb of
> 5200 feet per min. over 2000 feet per min than the zero was capable of,
> Its red lines dive speed was 450 mph.

Horikoshi claimed greater than 490 km/hr uncorrected. He was trying for
500 km/hr. 
 
> In was in every respect superior to the Japnese Zero.

> My question is why would the Zero with an empty weight of a little over
> 5,000 pound was built so flimsy unless it was a designe flaw, and he
> used the above excuse to save face?
> 
> Erik Shilling.

As soon as the first prototype was assembled they weighed it - 1565.9 kg,
without small parts such as machine gun supports. 
Later before the first flight the total weight "including every part,
fuel, oil, and so forth" was 1620 kg (3570.5 lbs). 

If that is the weight without any military hardware, the CW-21 is even
more impressive. What was its engine?  Range? (if the engine didn't quit)

Horikoshi goes into considerable detail about catastrophic failure in a
dive. Two planes came apart in the air, one with a loud roaring sound
followed by a bang. The engine and propeller separated and the rest of the
aircraft fell in pieces. The other one lost some wing surface, then the
entire tail. Both were traced to lack of dynamic damping of control
surfaces. One had lost the elevator mass balance weight without anyone
noticing. A surviving pilot's report indicated that the wing's flutter
stiffness was reduced more than they calculated when the upper surface
rippled due to aerodynamic loading. That's why thicker metal improved dive
speed. 

You have written that the P-40 could dive at up to 510 MPH, and that one
of them also came apart in a dive with a strange sound. What limited the
dive speed?

-- 
James Wilkins
The Mitre Corp.
Bedford, MA

Subject: Re: Have you flown a Zero?
From: jesw@mitre.org (James Wilkins)
Date: May 16 1997
Newsgroups: rec.aviation.military

Here are the original 1937 specifications for Prototype 12, which became
the A6M Zero. 

* Escort fighter with dogfight performance superior to that of its opponents. 
  It must also be an interceptor capable of destroying enemy attackers. 

* Wing span less than 12 meters. 

* Faster than 500 km/hr at 4000 meters.

* Climb to 3000 meters in less than 3.5 minutes.

* Full power endurance on internal fuel 1.2 to 1.5 hours at 3000 meters, 
  1.5 to 2.0 hours with external tanks. 
  6 to 8 hours at economic cruise speed. 

     The translator notes this as 1870 km range on internal fuel, 
     3110 km with a drop tank. 

* Take off in 70 meters with 12 m/s headwind.

* Same dogfight performance as the Type 96 (Claude). 

* Two 20-mm cannon, two 7.7-mm machine guns.

* Radio and full direction-finding equipment. 

* Mitsubishi Zuisei Type 13 engine (875 hp at 3600 meters) or 
  Kinsei Type 46 engine (1070 hp at 4200 meters) 

He hints repeatedly that the extremely long range and heavy 20-mm cannon
were what made the design so difficult. 

" For it to have high speed and superior dogfight performance, a light and
powerful engine would be needed. Since such a power plant was not
available, to my regret, in Japan at that time, it was necessary to design
the airplane so light that it defied common sense."

-- 
James Wilkins
The Mitre Corp.
Bedford, MA

From: .charles.k.scott@dartmouth.edu (corky Scott)
Newsgroups: rec.aviation.military
Subject: Re: Was the Zero the best plane of WWII?
Date: 7 Aug 1996 13:29:57 GMT

In article <4u8rce$sn0@fu-berlin.de>
gustin@hhipe.uia.ac.be (Emmanuel.Gustin) writes:

> Realistically, the A6M and the F4F were, when they fought in 1941--1942,
> of about equal value. Their weaknesses and strenghts were very different,
> but the balance was about even. The later USN and USMC fighters, the F6F
> and F4U, totally outclassed the Zero.

Another authoritative and accurate post from Emmanuel, most of which I
deleted for brevity's sake.

I can only add an interesting aside about the vulnerability of the A6M
and almost all the Japanese early to mid WWII aircraft.

In order to maximise the fuel tankage in the Zero, the engineers
considered but discarded the idea of using self sealing wing tanks
because the tanks of the self sealing variety did not hold as much fuel
as standard aluminum tanks.  Further, in order to maximize the size of
the tankage, the tanks were formed so that they completely filled the
fuel bay and actualy lay against the wing spars and wing skin.  This
fact was discovered when the Aleutians Zero was recovered and inspected
by American engineers.

The reason this is significant is because of the physics of liquid and
how it reacts to the passage through it of a supersonic projectile. 
Since fluids are incompressible when a supersonic bullet or projectile
passes through it trailing a shock wave, the fuel explosively expands. 
This expansion had a direct and catastrophic effect on the surrounding
structural members.

Early combat reports of US fighters sometimes remarked that after
hitting a Zero in it's wing root, the entire wing blew off with a
resultant fireball.  This didn't always happen but did occur often
enough that military experts were wondering what was causing the
phenomenon.  The tightly fitted metal tank was the answer.

The engineers who developed the self sealing fuel tanks for the F6F
Hellcat used as a benchmark, the .50 caliber machine gun.  They'd
develop a tank and set it out on the firing range and shoot a single
round through it to see how it faired.  Metal tanks blew apart.  So
bladder type tanks were used with a sandwich of raw rubber between
layers of fabric.  When the bullet passed through the layers, the
gasoline leaked around the hole.  The leaking gas reacted with the raw
rubber causing it so swell and seal the hole.  This couldn't help when
the tank was hit by an explosive shell but worked for non explosive
bullet hits.

The downside was that the fuel bladder had to be suspended inside the
wing with room for expansion when a bullet passed through it or the
wing would suffer the same type of catastrophic failure that was
occuring to the Zero.  How did they get around this problem?  The
Hellcat had the biggest wing of any fighter that flew in WWII.  (Source
"Naval Institute. Proceedings")

Corky Scott

From: paustin@harris.com (Paul F Austin)
Newsgroups: rec.aviation.military
Subject: Re: Was the Zero the best plane of WWII?
Date: Thu, 8 Aug 1996 09:23:57

In article <4ua5ol$fn4@dartvax.dartmouth.edu>
.charles.k.scott@dartmouth.edu (corky Scott) writes:

>From: .charles.k.scott@dartmouth.edu (corky Scott)
>Subject: Re: Was the Zero the best plane of WWII?
>Date: 7 Aug 1996 13:29:57 GMT

<snippa>

>In order to maximise the fuel tankage in the Zero, the engineers
>considered but discarded the idea of using self sealing wing tanks
>because the tanks of the self sealing variety did not hold as much fuel
>as standard aluminum tanks.  Further, in order to maximize the size of
>the tankage, the tanks were formed so that they completely filled the
>fuel bay and actualy lay against the wing spars and wing skin.  This
>fact was discovered when the Aleutians Zero was recovered and inspected
>by American engineers.

>The reason this is significant is because of the physics of liquid and
>how it reacts to the passage through it of a supersonic projectile. 
>Since fluids are incompressible when a supersonic bullet or projectile
>passes through it trailing a shock wave, the fuel explosively expands. 
>This expansion had a direct and catastrophic effect on the surrounding
>structural members.

Corky, a nit.

There's a lot of misconceptions about projectiles traveling through liquids. 
The biggest is the one you refered to above about "supersonic bullet or 
projectile". No such thing. The speed of sound in kerosene (couldn't find teh 
SoS of AvGas within reach) is 1320m/s. Any bullet or projectile fired from an 
US fighter was distinctly subsonic _in the liquid_. The effect you refered to 
could be caused by _hydrostatic_ shock when a projectile hits a full tank.


In politics, sincerity is everything.
If you learn to fake that, you've got it made.
-------------------------------------
Paul Austin
PAUSTIN@HARRIS.COM

From: Jordan@worldwar2aviation.com (C.C. Jordan)
Newsgroups: soc.history.war.world-war-ii
Subject: Re: Planes of ww2
Date: 5 Nov 1999 13:40:28 -0800

On Fri, 05 Nov 1999 06:22:01 GMT, walterm140@aol.com (WalterM140) wrote:

>I'd like to put iin a vote for the F4F Wildcat.   It was instrumental in all
>the 1942 naval battles (and also at Guadalcanal).  The pilots well knew they
>were in an inferior aircraft. And they still did a great job against an
>extremely well trained enemy.
>
>Wildcats flew throughout the war with U.S. and Commonwealth forces.

I certainly agree that the F4F should be on any list of great fighters of WWII.
However, the F4F was not inferior to anything the Japanese were flying during
the same time period. The IJN's A6M2 (Model 21) held only a few advantages over
the Wildcat. It held an advantage in turn rate at low speeds. It also climbed
better at low to medium altitudes. That is it.

What about speed? Isn't the Zero faster than the Wildcat?
No. The commonly published maximum speed of the Zero comes from U.S.
testing of a captured plane. However, this fighter was stripped of its guns
and was tested using 100 octane fuel, none of which the Japanese had
at any time during the war. Numbers from Japan indicate that the A6M2
could do no better than 312 mph.

The Wildcat (F4F-3) could pull 322 mph. At any speed, the F4F rolled
faster than the Zero. At 200 mph and higher, the Zero could barely roll
at all. Of course, at speeds above corner speed (about 250 mph) turn rate
was more dependent on the pilot's ability to withstand G loading. So, the far
more sturdily constructed Wildcat, being able to sustain greater G levels, had
the advantage if the pilot could stand the load.

The F4F could easily out-dive the A6M, both in terms of acceleration and
maximum (VnE) speed attainable. Virtually any F4F had better guns (especially
the F4F-4) largely because the Zero's 20 mm cannon were ineffective and the
rifle caliber machine guns were not only ineffective as well, but badly
out-ranged by the Grumman's .50 caliber Brownings.

The Wildcat was well armored and had self-sealing fuel tanks. The A6M2
had neither. The Wildcat was far more ruggedly constructed than the lightweight
Zeke.

Due to being fitted with a two stage, two speed supercharger, the speed
advantage of the F4F only increased with altitude.

Perhaps, some day, the myth of the Zero's performance will finally be replaced
down to tactics and experience of the pilots.

My regards,
C.C. Jordan

The Planes and Pilots of WWII Internet Magazine
http://www.worldwar2aviation.com
http://www.cradleofaviation.org - Cradle of Aviation Museum

From: erikavg@ix.netcom.com (Erik Shilling)
Newsgroups: soc.history.war.world-war-ii
Subject: Re: Planes of ww2
Date: 5 Nov 1999 21:40:34 -0500

In <38232a97.2622866@netnews.worldnet.att.net>
Jordan@worldwar2aviation.com (C.C. Jordan) writes:
>
>What about speed? Isn't the Zero faster than the Wildcat?
>No.
snip
T Numbers from Japan indicate that the A6M2
>could do no better than 312 mph.
About 5 years ago while Saburo Sakai was in Los Angeles I had the
oprotunity to talk to him. One of the question I ask was what was the
Zero's top speed with full armor.

His answer was 309 mph. He also said tht Japanese pilots would not dive
above 300 mph IAS, becasue the skin on the wings started wrinkling and
caused the pilot great concern. He also added to this that above 300 it
was almost impossible to roll.

Erik Shilling

From: Jordan@worldwar2aviation.com (C.C. Jordan)
Newsgroups: soc.history.war.world-war-ii
Subject: Re: F4F Wildcat was Planes of ww2
Date: 8 Nov 1999 08:40:56 -0800

On Sun, 07 Nov 1999 03:55:21 GMT, walterm140@aol.com (WalterM140) wrote:

><<I certainly agree that the F4F should be on any list of great fighters of
>WWII. However, the F4F was not inferior to anything the Japanese were flying
>during the same time period. >>
>
>You make some excellent points, but Admiral James Thach would disagree with
>you:
>
>>From "The First Team" by Jon Lundstrom
>
>"The FATU Intelligence Bulletin of 22 November 1941 gave the Zero a top
>speed of between 345 and 380 miles per hour, a cruse of between 210 mph
>and 250 mph and an armament of two 20-mm cannons and two 7.7-mm machine
>guns.

This only goes to show that often, Intelligence estimates can be wildly off the
mark. Certainly no A6M2 ever got close to 345 mph, much less 380 mph.

>Thach also
>may have seen other estimates, emanating from Claire Chennault in China.
>Chennault possessed first hand experience in battling the Zero.  He rated
>its top speed at 322 mph, but more important, warned of the Mitsubishi's
>incredible maneuverabilty and high climb rate. At any rate, the estimates
>sketched a formidable opponent, if one gave any credence to them.

Chennault had VERY limited experience with the Zero. The Japanese only
employed a handful of them in 1940 for evaluation purposes. They were a
vast improvement over the Ki-27 Nate, but they were quickly withdrawn from
the theater. Chennault may have seen one of these early aircraft which had been
wrecked. However, the Chinese and, specifically, the AVG encountered
only Japanese Army fighters such as the Ki-27 and early models of the Ki-43
Hayabusa (Oscar).

The A6M2's rate of climb was not especially terrific. It could climb at about
3,050 ft/min. That was better than the Curtiss Tomahawk, and the F4F, but
not by more than 400 ft/min. The Republic P-43, of which the Chinese received
just over 100, could give the A6M2 a run for its money in climb rate,
especially above 15,000 ft. The P-43 was capable of better than 355 mph.

The way to foil the Zero was to have the edge in speed at the beginning of an
engagement. With its two stage, two speed supercharger, the F4F could arrive
with an altitude advantage. That automatically translates into a speed
advantage.

>Thach was inclined to credit the reports he saw, as he felt they had been
>written by a fighter pilot."  p 601

Well, just because he believed the reports, doesn't make the reports
accurate.

>
>
>  Jimmy Flatley would also disagree:
>
>"Setting up shop early that June [1942] with his nascent Fighting Ten at
>North Island, Jimmy Flatley observed with interest the brouhaha between
>the fleet and BuAer [Bureau of Aeronautics].  His first inclination after
>flying the F4F-4 in March was to side with the others and down check the
>portly -4 as an unworthy replacement for the F4F-3.  Then came his first
>combat at Coral Sea, and he realized that when battling Zeros, the
>difference in performance between the F4F-3 and the F4F-4 really meant
>nothing.  Individually neither was a match for the nimble Mitsubishi in
>dogfighting...

That's the whole point. The Zero's strength lies in its excellent low speed
turning ability. Therefore, to negate that advantage, you don't engage in
low speed dogfights. Never fight the way your enemy fights best. Once
this sunk in to brains of the pilots, the Zero was no longer such a daunting
foe.

>[Flately wrote]  "What the F4F-4
>lacks in climb and maneuverability is more than compensated for by its
>excellent armament, protective armor, protected fuel system, and greater
>strength.

Exactly my point. He doesn't mention the A6M2 having a speed advantage,
which it didn't have.

>Add to
>this the inherent superior ability of the [U.S.] Navy pilot, particularly
>as regards using his  armament, and the outlook is very favorable...Let us not
>condemn our equipment.  It shoots the enemey down in flames and gets most
>of us back to our base...let's take stock of ourselves and get to work
>and quit griping about our planes." p. 563-64
>
>Of course the USN/USMC pilots worked in pairs very succesfully and eschewed
>dogfighting with the Zeros, but one on one, and given the excellent
>training and experience of the Japanese, you were in a disadvantage in
>the F4F.

Only if you were caught low and slow. Again, the Zero could not hope to follow
the F4F through a split s with any expectation of catching a diving Wildcat.
Worse, if the A6M does follow the F4F down the tables can be turned quickly.

Remember, the best Japanese pilot cannot shoot down an enemy that can't
be caught.


>Note:  The -3 Wildcat had non folding wings and 4 .50 cal machine guns.
>The -4 had a wing folding mechanism and 6 .50 cals.  It was 900 lbs
>heavier than the -3, but more could be embarked on the carriers by about
>50%.

Many pilots felt that the added weight of the F4F-4 was not offset by
the two additional MGs. Nonetheless, the extra weight was not a factor
unless one got involved in low speed turning or a sustained climb, both
of which were a bad idea when fighting Zeros anyway.

My regards,
C.C. Jordan

The Planes and Pilots of WWII Internet Magazine
http://www.worldwar2aviation.com
http://www.cradleofaviation.org - Cradle of Aviation Museum

From: David Lednicer <dave@amiwest.com>
Newsgroups: rec.aviation.military
Subject: Re: Japanese Zero an American Design?
Date: Thu, 08 Jul 1999 15:47:25 +0100

Beth Fisher wrote:
> I thought I saw a Discovery channel program a few years ago that claimed the
> Zero was based on an American design which the Allies rejected.
>
> Does anyone know if this is true, and if so who the designer was?

	Yes, some western aircraft were sold to Japan before the war and
examined there as examples of aircraft construction.  However, the story
of the Zero being a US design is total BS - the aircraft was designed by
a team led by Jiro Horikoshi at Mitsubishi Heavy Industries.  See his
book: "Eagles of Mitsubishi" for the full story.

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