EXAMINATION OF JAPANESE AIRCRAFT AILERON TIP
USS ENTERPRISE (CV-6), 11 APRIL 1945
In 2004, I purchased a Japanese aircraft aileron tip on eBay. The
item was reported to be the tip of stabilizer from a Kamikaze plane that
hit the USS Enterprise on 11 Apr 45. The auction’s description
stated that the seller’s uncle was a sheet metal worker at that
time on the USS Enterprise.
Figure 1: USS Enterprise’s starboard beam on September
13, 1945. Original Puget Sound Photo: R. Lane collection.
Figure 2: Aileron tip upper surface.
The lower surface of the aileron tip’s fabric has penciled text: “April
11, 1945, Port Side FR.157, USS Enterprise.” The “Port
Side” refers to side of the USS Enterprise that was attacked by
the Kamikaze plane. The “FR 157” may refer to a frame
section on the USS Enterprise that was damaged by a Kamikaze on 11 Apr
Figure 3: Aileron tip lower surface.
DETAILED ANALYSIS – KAMIKAZE ATTACK ON USS
Before analyzing the aileron tip, this article will summarize the 11
Apr 45 Kamikaze attacks on the USS Enterprise. A full copy of the
USS Enterprise Damage Report is available at cv6.org. Excerpts
from the report are included below.
On 24 March 1945, Enterprise anchored in Ulithi where repairs
to the damage received on 18 and 20 March were undertaken by the ship's
force and personnel from USS Jason. They were not completed
in time for her to participate in the 1 April landings on Okinawa, but
by 7 April she was able to join Task Group 58.3 operating to the east
of Okinawa. A large-scale Kamikaze attack developed against Task Group
58.3 on 11 April northeast of Okinawa. At 1345 two large groups of Japanese
aircraft were noted closing from the north. Enterprise opened
fire on two planes at 1408, shooting one down about 1500 yards off the
starboard quarter. The other dived on the port quarter, struck two 40mm
mounts and fell into the sea. The bomb carried by the plane detonated
beneath the ship. At 1500 another Japanese plane carrying a bomb attempted
a suicide dive but missed and struck the water 45 to 50 feet off the
Figure 4: USS Enterprise’s flight deck showered with sea
water and flaming
debris from the first Kamikaze near-miss aircraft. Photo
Figure 5: Approximate path of the first Kamikaze plane and near
miss of 11 Apr 45.
Scanned from an original
copy of the USS Enterprise (CV6) War History,
7 Dec 1941 to 15
Aug 1945 (dated 30 Apr 1947). Diagram
courtesy Joe Nichols.
The outboard gun shields and semicircular platforms of 40mm mounts Nos.
8 and 10 were sheared off or bent by impact of the plane and blast from
the first near-miss. Parts of the plane remained in the gun tubs.
Figure 6: First near-miss Kamikaze plane sheared off the outboard
shields of the two 40mm anti-aircraft
gun platforms on Enterprise's
port quarter, 11 Apr 45. Photo courtesy cv6.org.
The action report stated the belief that both near-misses were by Judy-11's.
However, a photograph shows a head-on view just before the crash, which
indicates that the plane which grazed the port quarter was a Zeke-52,
with a bomb slung under its fuselage. The plane which fell off the starboard
bow was probably a Judy-11, judging from the action report and from a
photograph of the piece of the wing recovered on the flight deck.
The first plane's engine struck the blister at frame 136, tearing a
3-foot by 2-foot hole into D-54-F at the waterline. Except where torn
open by the impact of the plane's engine, the welded blister plating
did not develop cracks or tears from the first near-miss. In contrast
to this, rivets popped and seams opened in the original hull even where
protected by the blister.
Figure 7: Damage to Enterprise's hull, port-side aft, caused by
the first Kamikaze near-miss,
11 Apr 45. Photo courtesy cv6.org.
Figure 8: Approximate path of the first Kamikaze plane and near
miss of 11 Apr 45.
Scanned from an original copy of the USS Enterprise
(CV-6) War History,
7 Dec 1941 to 15 Aug
1945 (dated 30 Apr 1947). Diagram
courtesy Joe Nichols.
The bomb from the second Japanese plane detonated 45 to 50 feet off
the starboard bow, causing additional shock damage and slight structural
damage in six tanks and voids. Water spray carried as far aft as the
pilothouse and part of the plane wing was hurled to the flight deck. Note:
Steve Ewing recounts how this wing piece was recovered in his book, “USS
Enterprise (CV-6) The Most Decorated Ship of World War II” (1982),
page 146. The passage reads; “A crewmember ran forward, took
hold of the wing and began pulling it toward the island. Half way
to his destination he stopped, pulled out a pen and wrote on the wing, “this
wing is the property of W.W. Wahl AMM 1/C.”
Figure 9: John Yocum SC 3/c standing beside the wing of a "Judy" that
crashed into Enterprise CV-6, 11 Apr 45.
This wing is from the second
near-miss Kamikaze plane that attacked the Enterprise on 11
The wing was preserved and placed on display in the Washington Navy
Yard after the war.
Photo courtesy cv6.org. Note: A color photo
of this same wing piece can be seen at Claus Kruger’s
photo gallery at: http://www.j-aircraft.com/familyphotos/claus_kruger/flache_01l.jpg
Damage Report Conclusion: It is evident that the first near-miss
Kamikaze plane was a Zeke-52 (A6M5) and parts of the plane remained in
the gun tubs. The second Kamikaze plane was a Judy-11 and part
of the plane’s wing was hurled onto the flight deck.
DETAILED ANALYSIS – AILERON TIP
The aileron tip measures 9 x 12 inches and is fabric covered on the
lower and upper surfaces. The piece is in an amazing state of preservation
and it appears as if this relic was stored away in a dark place for over
60 years. The fabric is still tight under tension and the paint
is in excellent, original condition.
Figure 10: Aileron tip upper surface.
Figure 11: Aileron tip lower surface with penciled text.
Figure 12: Detail of two internal ink stamps, close up of upper
fabric impact damage, and lightening hole/wood support piece.
Figure 13: Detail of another internal ink stamp and several fabric
The first step was to verify the type of aircraft this piece was removed
from. From the official damage report, we know that one near-miss
Kamikaze aircraft was a Zeke-52 and the other a Judy-11. Jim Long
provided the following detailed analysis.
JIM LONG’S DETAILED ANALYSIS
I believe we can conclude that the aileron tip is from an A6M5 and not
from a Judy type aircraft.
Using measurements and photo scans, I have located the tip piece on
a copy of a portion of an official WWII technical diagram from a handling
manual. See Figure 1.
Figure 1. Close-up detail of the left wing tip of an A6M5
This diagram is from Page 381 of “Zero Fighter
published by KK Bestsellers, Tokyo,
2001, ISBN4-584-17084-3 C0020.
The portion colored green represents
the piece referenced in this report...
Though this was a technical drawing from WWII and should have been accurate,
it has a mistake on it. While doing this research, I discovered
that the original draftsman misidentified the location of the aileron’s
counterbalance weight at the outboard position. The four Japanese
written characters in the space between Stations 25 and 26 mean “Balance
Weight.” But the line points out a dashed-line item in the
outer end between Stations 24 and 25 that I believe represents the piece
of wood used in the nose of the aileron for added strength. The
table that details the values and locations of the balance weights, appearing
on the same page as the drawing, supports the supposition that the draftsman
erred. The draftsman should have had his line running to the orange
colored item, which was the outer counterbalance weight.
Rich reported that the piece of wood in his relic ran the whole length
of the aileron tip. The drawing does not confirm that. Instead
it indicates that the piece of wood ran only from the left side of the
hinge cutout to the left side of the last rib in the aileron. The
drawing is a Mitsubishi product and this might be significant. If
we could determine that the Mitsubishi-built aileron was different from
the Nakajima-built one in this respect, we would have some valuable information.
And now I call your attention to the two round items that I have color-coded
in yellow. Rich said his piece had a small vent hole on the underside
that had a metal grommet for reinforcement. We can see it in Figure
3, below. At first I thought these two yellow items on the drawing
represented two such vent holes. But on closer examination, I
noted that the holes were in areas that were made of metal. I looked
around for an explanation and soon found something on one of Rich’s
scans. A flanged lightening hole can just be seen in the shadow
on one of the scans. I believe the circles on the drawing represent
lightening holes, of which the outermost one is in Rich’s relic. The
picture is in Figure 2, below.
Figure 2: A lightening hole in the bottom surface of the metal
portion of the aileron tip.
The Douglas report doesn’t help us any with a detailed description
of the construction of the aileron. Be that as it may, the portion
that should interest us in this discussion is the information about the
fabric material on control surfaces. The portion inspected was
from the rudder, but I feel that it would be representative of the covering
on the ailerons, as well. I’ve excerpted the material and
am presenting it here Attachment 1. To complete this report, I’m
including a scan of the complete aileron as Attachment 2, on which I’m
showing the details I’ve spoken of, with the counterbalance weights
shown in yellow, the wooden reinforcements shown in green, and the lightening
holes shown in orange.
The little grommet hole is probably to equalize air pressure. It’s
just my guess. As for the colors, they seem about right. As
to whether they are Mitsubishi or Nakajima colors, I couldn’t say,
and I defer to Jim Lansdale on this question.
Figure 3: Small reinforced vent hole in the fabric on the bottom
surface of the aileron tip.
I conclude that Rich has a notable relic because we know that it came
from a Zeke, and it is associated with a particular historical event.
Excerpt from Report No. ES6744, ENGINEERING INSPECTION - JAPANESE ZEKE
52 AIRPLANE, February 1, 1945, by R. Anderson of the Douglas Aircraft
Company, Inc., El Segundo Plant.
15.1 FABRIC COVERING OF CONTROL SURFACES
For the purpose of
determining the type and quality
of materials used for covering and finishing fabric covered
control surfaces and the methods used to attach fabric to
the frames, an investigation was made of a typical fabric
covered Zeke 52 control surface. Although partly destroyed,
the rudder assembly was used as a specimen for this purpose.
The fabric taken from
the specimen was found to be
in excellent condition. No mildew or mold growth of any
nature was in evidence. Considering the partially de-
stroyed condition of the frame structure, the tautness of
the fabric covering was regarded as being fair although
actual deflection readings were not taken.
The Japanese fabric covering material
resented by the test specimen appears to be a cot-
ton cloth of very good quality. In comparison with
American Grade A airplane cloth, the fabric has a
harder finish but the texture is not as smooth and
uniform. The strands are twisted tighter but with
a considerable variation in size. The weave is
one up and one down (Basketweave) and more loosely
woven than American fabric. In general, the fab-
ric is inferior to American fabric in that it does
not offer as good a base for the anchorage of dope
coatings and more surface coatings are required to
obtain a smooth finish.
of two test specimens deter-
number of threads per linear inch to be
cordwise and 76 threads spanwise. The
strength of these two specimens was found
- 53 and. 76 lbs. per inch
- 73 and 83.5 lbs. per inch
weight of the fabric was determined to be 3.77
and cover tapes are made from
fabric used for cover material. The edges
of the cover
tapes are not pinked but frayed by
out a few threads along the edge of the
reinforcing tapes used are 5/16 inch
the cover tapes vary in width from
analysis of the lacing cords indicates
material used is a good grade of cotton.
breaking strength of six lacing cord
was 45.8 pounds.
analysis of the surface coating mate-
that a variety of Cellulose Acetate
Dope is used. The coating film is of ex-
quality although the texture of the fabric
been filled to a smooth uniform surface.
A light gray synthetic type primer
brush coated on the areas of the control surface
frames in contact with the fabric. This coating
has probably been applied to give the acetate dope
adhestion to the metal frame and to protect the alu-
minum from the dope coating.
of the surface coating is
excellent and the flame resistance of the material
was found to be exceptionally good. The film will
ignite in direct flame but will not continue to
bum. The total weight of the coated surface is
4.477 ounces per square yard.
15.13 METHOD OP ATTACHING FABRIC
The cover fabric was
found to be attached to the
surface ribs by an over and under type of lacing with the
lacing cord tied only in one place at the trailing edge.
The lacing cord is protected from the sharp edges of holes
in the rib flanges by means of small metal eyelets. The
spacing of lacing holes in ribs varies from 9/16 to 1-5/8
It is noteworthy that the cover
fabric was found to
be attached with the warp running spanwise and that re-
inforcing and cover tapes are used very sparingly. It was
also noted that taping and padding is not placed on the
frame prior to covering. This is an indication that every
effort is exercised to save weight and conserve materials.
The cover fabric is
closed on the leading edge of
the surface by machine sewing and by hand sewing at the
root end and in the tab attaching area. At the trailing
edge, fabrics from the two side surfaces are attached to-
gether by doping.
Reinforcing and cover tapes are
applied only over
the laced and sewed areas. After untying the knot in the
lacing cord at the trailing edge of the surface, the cover
tapes and covering were very easily removed in one piece
and all cords and sewing threads were found to be in per-
fect condition after removal.
It is considered
that the method of attaching fab-
ric to the Zeke 52 control frames and the reinforcing of
the fabric is not equal to American methods.
15.14 METHOD OF APPLYING SURFACE COATING
Examination of the coating
film by scraping through
from both sides of a section of film and by placing a cross
section of film under a microscope indicates that the sur-
face coating was applied in six operations.
It is believed that the application
(a) Two brushed coats of clear
tapes being applied with the second coat.
sprayed coat of medium wet red
sprayed very heavy coat of light
sprayed very thin coat of alumi
(e) One sprayed
coat of medium wet dark
on the amount of clear dope remaining in the
fabric after the surface coating had been peeled off, it
is believed that the first wet down coat was not too well
brushed into the fabric, with the result that the cloth
was not well saturated with the dope coating. It was de-
termined that only .317 ounces per square yard of clear
dope remained in the fabric. American Grade A fabric
properly coated with either Cellulose Nitrate or Cellulose
Acetate Butyrate Dope will retain not less than .50 ounces
per square yard.
of the coating and cover tapes to the base
fabric was found to be exceptionally low, peeling off with
a pull of between 3.7 to 6.0 pounds. American cover tapes
(2-1/4 inch tapes) will not pull off at less than 10.0
pounds and generally average 13.5 to 14.0 pounds.
Jim Lansdale analyzed the aileron tip and obtained color readings of
Munsell 2.5 GY2/2 for upper surface dark green and the lower surface
Munsell 7.5 Y 4/2 (close to Federal Standards 595 FS-16350). Jim
concluded that these colors match a Nakajima produced A6M5 Zero Fighter
From the USS Enterprise 11 Apr 45 damage report, we know the first Kamikaze
plane was an A6M5 Zero and parts of the plane remained in the 40mm gun
tubs. The second Kamikaze plane was a Judy-11 and part of the plane’s
wing was hurled to the flight deck. From Jim Long’s detailed
analysis, we know this aileron tip was from the port side of an A6M5
Zero. Jim Lansdale further documented that the upper/lower colors
matched a Nakajima produced A6M5. What is still unknown,
and requires further research, is information about the Japanese pilots
of either the Judy-11 or Zeke-52 from these 11 Apr 45 Kamikaze missions.
1. USS Enterprise (CV6) War History, 7 Dec 1941 to 15 Aug 1945 (dated
30 Apr 1947).
Joe Nichols purchased an original copy of this document on eBay in 2004. He
provided me the detailed scans of the diagrams that depict the Kamikaze
attacks on 11 Apr 45.
2. cv6.org. The image library has several photographs of the damage
caused by the A6M5 Zero Fighter and Judy-11 that attacked the USS Enterprise
on 11 Apr 45. The web site also has the damage report for the USS
3. Jim Lansdale and Jim Long. Both were instrumental in documenting
this aileron tip. Jim Long provided a detailed report that was
incorporated in this article.
4. USS Enterprise (CV-6) The Most Decorated Ship of World War II,
Steve Ewing, Pictorial Histories Publishing Company, 1982