Thursday 31 October 2019

CINCPAC - CINCPOA Translations - Attacking Large Bombers Pt. 2

Part #2
Air patrol carried out at 3500 meters. Enemy sighted at 6000-5000 meters, bearing 040°. The 1st CHUTAI immediately approached enemy. The 2nd CHUTAI turned inside at high speed and, coming out in front of the last CHUTAI, engaged A's direct escort unit in a head-on approach and recovered below. The 1st CHUTAI deployed and made an overhead approach.
The cooperation of the 1st and 2nd CHUTAI was in general well timed.
The 2nd CHUTAI (diversion unit), after passing the direct escort unit in a head-on approach, made an overhead attack against the enemy attack planes. (The latter were judged to be too far away from the direct escort unit). A's 3rd SHOTAI delivered a head-one attack which was considered effective on the whole.
The 1st and 2nd SHOTAI of Force A made a head-one attack against B's diversion unit, pulled out, and then attempted to attack those planes of Force B which were trying to an over-head approach, but were unable to deliver a positive attack from a 600-800 meter firing range.
It was judged that B's attack unit did not consider this approach and could have made a run.
a. Since the number of planes on both sides was small during this trial, we can only imagine what would have happened with more planes participating. To conclude that Force A was able to check Force B skillfully with just 12 fighters is premature; greater participating strengths should be assumed in judging.

b. Since Force B was composed entirely of Zero fighters during the trial, it was more convenient to use them without distinguishing between a diversion unit and an attack unit; but further study on this matter is necessary.
1. The leading unit made the diversion unit, without its being considered a separate entity. The leading unit may proceed as usual and make a run, if it appears that an overhead attack is warranted by the condition of the direct escort unit, in which case the next SHOTAI will become the diversion unit. Or, the entire force, or a part of it, may make a surprise overhead attack.
2. Operating with two distinct units.
(It is assumed that local interceptors () will seek out enemy fighters but not engage them in combat).

c. The air patrol unit (JOKU SHOKAI TAI)
1. Patrol formations, maneuvers, disposition, and approaches.
Example: When the enemy bombers are well spread out, the unit making the overhead attack will approach and strike, also in spread-out formation.
2. The overhead approach.
When there are three enemy planes or less, there should be 300 meters distance between each BUNTAI attacking. If the enemy planes are about one CHUTAI strong, the attack is made by one SHOTAI at a time. The distance between the 1st and 2nd BUNTAI is approximately 100 meters with the 1st BUNTAI on the outside and the 2nd BUNTAI on the inside. The distance between SHOTAI will be about 300 meters, and the attack carried out as with BUNTAI alone.

d. In an attack by local interceptors against large planes, KO () fighters should go along as direct cover, to oppose interference by enemy direct escort planes which must certainly be expected.
Combat methods for this type of diversion unit and methods for its cooperation with the attack (local interceptor) unit remain open for investigation.

e. To protect a land attack plane unit against an attacking fighter unit approaching on opposite course and making a wide-angle, overhead attack, it is thought best to have the direct escort unit disposed 2000-2500 meters forward of the land attack plane unit and 1500 meters higher.


Force A assumed assault formation () at 0840 immediately after making its rendezvous, but the medium attack plane unit then turned to the left. The 3rd SHOTAI (MASUDA SHOTAI), which was farthest in advance, did not observe this, lost sight of its companion units, and continued separately on its course. The 1st SHOTAI (TSUKAMOTO SHOTAI) and 2nd SHOTAI (OKI SHOTAI) also delayed in turning; and in the approach to the objective, the 2nd SHOTAI pulled too far to the side and lost sight of the medium attack plane unit. The 3rd SHOTAI, proceeding directly, sighted the "enemy" fighter unit (Force B's diversion unit) at 0850. When it turned to the left during its engagement with these fighters, it noticed the medium attack plane unit far behind and flew back in an attempt to reassume its escort station. The 1st SHOTAI, mistaking the 3rd SHOTAI for Force B, veered to the right. 
At this point the KODA CHUTAI of Force B made its run on the medium attack plane unit. Although the 1st SHOTAI executed a head-on attack against the 2nd SHOTAI of Force B (OKUTANI SHOTAI), it was a little too late. In the meantime, the 3rd SHOTAI reengaged B's diversion unit to the right as the latter came in for a run, and hastened to its direct escort station. But it was too late; the medium attack plane unit had already been attacked.   

1. Since the starting points were too close, and visibility was exceptionally good, it was difficult to simulate the attack approach of actual combat.
2. The direct escort units, as soon as they were in assault formation, carried out weaving together, 2000-2500 meters in front of the medium attack plane unit and at an altitude increment of 1000-1200 meters.
Though exercising their maneuverability in this manner, they should not lose sight of the medium attack plane unit. (This maneuver is admittedly difficult.)
3. Since the 3rd SHOTAI (MASUDA SHOTAI) became separated, a tryout of the double-level disposition () was impossible.
4. The cooperation between diversion and attack units, which became separated, was poor. The diversion unit should always protect the attack unit to permit the latter's making an effective overhead approach. (Further experiment is necessary on the position the diversion unit should maintain and on the timing of its run.)
5. Since the 2nd and 3rd SHOTAI of B's attack unit made their runs at almost the same time, a bracketing attack developed. Here the SHOTAI leaders should use proper judgement, to break off the attack, and maneuver for a second decisive approach, once their planes have reformed after a good break-away.
6. In patrol formation, it is important that each SHOTAI and each plane should not become separated too much. There have been times when the CHUTAI commander has decided to attack, but the chance to engage was lost, through the disrupted or unprepared attack formation of succeeding SHOTAI.    



Force A's medium attack plane unit set its course prematurely, so that the direct escort unit was unable to assume its proper assault formation. The 3rd SHOTAI (MATSUBA SHOTAI) was late in getting into its supporting position and fell behind.
Force B's diversion unit (2d, or MASUDA CHUTAI) sighted Force A at 1034 and approached the latter's direct escort unit (at 3600 meters). Force B's attack unit turned on sighting the enemy, but its formation became confused owing to the delay of the 2nd (OKI) and 3d (YAMAKAWA) SHOTAI in turning. Although the 2nd CHUTAI presented a satisfactory high cover screen (), the 1st and 2nd SHOTAI of Force A's direct escort unit avoided engagement with them and made an undeviating head-one attack against Force B's 1st CHUTAI.
In the meantime, the 2nd CHUTAI of Force B inflicted a head-on attack and an overhead attack on Force A's 1st and 2nd SHOTAI respectively. Force B's 1st CHUTAI was checked by the direct escort units; and because it rolled over too soon, its dive was too steep. But it immediately pulled out, looped, and attacked satisfactorily. The movement of Shotai 2 and 3 of Force B was held in check by the direct escort unit; they had to be contented ultimately with a weak attack.
The 2d BUNTAI of the 2d SHOTAI proceeded independently to the left, where the direct escort unit was thinly dispersed, and made a successful attack.     
1. When the direct escort unit of Force A was attacked by the diversion unit of Force B, it should have counter attacked and then evaded, as in actual battle. It should not, however, get too involved in combat, lest it leave the medium attack planes exposed. In this encounter, its evasion was insufficient, and it was subjected to attack.
2. When unable to effect a steep overhead approach because of poor position, it is better not to go ahead with the attack, but to withdraw temporarily and plan a strike which will be sure not to fail.
The maneuver of the 2d BUNTAI (TAISHOYA BUNTAI) of the 2nd SHOTAI in Force B's 1st CHUTAI was well timed.
Greater stress should be placed these days on the attack formation of fighters on the timing of their attack.
(YAGI, Air Group Comdr.)


The medium attack plane unit was delayed in its take-off; and while the direct escort unit waited at the rendezvous, the 2nd and 3rd SHOTAIs became separated and started out on the attack before they could regain formation. The 2nd SHOTAI (OKI CHUTAI) and the 3rd SHOTAI (Lt. (jg) MASUDA) pushed ahead under full throttle, fell back and slightly to the left.
Force B sighted the "enemy" too late, and having no time to deploy, made its run while still in patrol formation, bearing 33  from the medium attack plane unit and with an altitude advantage of about 1200 meters. As a result, Force A's 3rd SHOTAI was able to deliver both a head-one and overhead attack against Force B.
The diversion unit of Force B was too late to check Force A's direct escort unit, which effectively attacked Force B's attack unit. The latter being also attacked in the center, fell behind. 
1. Because of bad formation flying by Force A's 2nd and 3rd SHOTAI over CHIBA, they were not in their assault formation positions. At the time of B's run the 2nd SHOTAI had fallen behind and the 3rd SHOTAI was off to the left. SHOTAI leaders must understand precisely the positions to be taken for direct escort and see to it that the formation is constantly maintained.
2. Although the direct escort unit stays behind and above the medium attack plane unit when advancing for the attack, it is advisable that it occupy a superior position 500-700 meters above the designated altitude in order to facilitate its proceeding ahead of the attack planes before the enemy's run.
3. There must be a plan for rallying under the CO's plane after completion of an attack. (301st Air Group)

Wednesday 30 October 2019

CINCPAC - CINCPOA Translations - Attacking Large Bombers Pt. 1

The next document, in three parts, is detailing ways to attack and shoot down heavy bombers and the results when Yokosuka and 301 Kokutai put these ideas to the test. A very rare and historically important document.


Source: Captured on SAIPAN.
Subject: Experiment and research on Methods of Attacking Large Bombers. Fragmentary document; undated; issuing authority unidentified, but this mimeographed reference work may possibly have been issued by the YOKOSUKA Naval Air Group.
Editor's Note:
This document was discussed at considerable length in CINCPAC-CINCPOA WEEKLY INTELLIGENCE, Vol. 1, No. 16, 27 Oct 1944, pages 28-32, and is reproduced here in full because of its value as a discussion of fighter tactics. 


                                                    (First Report) 
Attacks with Forward-Fixed Guns 
I. Object
To establish the most effective method of attack with forward-fixed guns, on armored, fireproofed, heavily protected large bombers.
II. Results and Comments 
A. Suitable methods of attack. 
1. Basic methods of attack.

a. Steep overhead (TN: Lit: from above & astern) attack. 
A steep overhead attack (angle at instant of firing:70°- 45°; firing range: 600 to 300 meters) is most effective and little damage is sustained by the attacking plane. It is considered the most suitable method of attacking large planes. Its advantages are as follows:
(1) Percentage of hits is good. For the reasons stated in paragraph (2), (3) and (4), a high percentage of hits is characteristic of this method.
(2) The approach and attack are simple; their essentials can he grasped by an inexperienced pilot with only a short period of training. 
(3) Execution of the attack is seldom affected by the enemy's formation at the time he is sighted or by his changing course during your approach.
(4) Errors in sighting, especially in firing range, are slight. 
(5) Since the relative angles of attack and breakaway are large, little damage is suffered from enemy defensive fire.
See Appendix #1 for essentials of the attack.
b. The effectiveness of the head-on attack, made from almost directly ahead (within 10° left or right and 15° above or below the enemy plane's line of flight; firing range 800 to 300 meters), is relatively great, and maneuvering for the attack is easy. This is considered a good method of attacking large planes.
See Appendix #1 for essentials of the attack. 

c. Firing with sights. The advantage of deflection (angle) firing ( ) are as follows: 
(1) Although deflection (angle) firing has the fault of making errors in the firing angle at once produce errors in deflection, it has little effect on errors in firing range. Because it is direct sighting, sighting errors are small, and the percentage of hits is higher than with deflection (amount) firing (). (2) In the overhead approach especially, the firing angle is large, producing some error in its calculation; but bullet drift is small, so from the practical standpoint the method is advantageous and there is no further need for consideration of it.
See Appendix #3 for the details of deflection (angle) firing. 

1. Attacking large planes provided with escort fighters. 

a. A combat air patrol (JOKU CHOKUEI TAI) is divided into a diversion unit (YUGEKITAI) and a bomber interception unit (BAKUGEKIKI GEKITSUI TAI).

b. The diversion unit will vary with the number of planes of each side and with the situation, but generally includes sixteen planes. It engages, checks and destroys enemy escort fighters, and gives indirect cover to the bomber interception unit.
The bomber interception unit usually consists of eight to sixteen planes. It avoids combat with enemy fighters and forcefully attacks and destroys enemy bombers. When necessary, the bomber intercpetion unit is divided into two parts, one concentrating on attacking the bombers, the other becoming a direct escort unit for the first.

c. Although it is preferable for the diversion unit and the bomber interception unit to be in strength when the number of planes on both sides is large, the optimum number is 32 planes, otherwise confusion in the air will result.

d. The diversion unit mast engage the enemy escort fighters before the bomber interception unit begins its assault. When the diversion unit is in strength, it is sometimes preferable to have it accompany the bomber interception unit to ensure coordination.

e. If a coordinated attack is executed by having a part carry out a frontal attack while the greater part makes an overhead assault, it gives the enemy no time to prepare and is very effective.

B. Improvements in armament.
In an overhead attack using 20 mm Mark II MG's (target speed being 250 knots), the deflection will be 9° 47' for the firing angle of 70° and range of 600 meters; or 7° for the firing angle of 45° and range of 300 meters. Because it is difficult to aim with the present sight and armament, the following is required:
1. Manufacture of sights with a good field of vision below and in front.
2. Elevation of MG's and sight at least 5° from the plane's longitudinal axis to improve the field of vision below and in front during firing.

C. Study of various methods of attack. 
1. If a stern attack from below is executed properly, it gets very good results with slight risk of damage. This attack requires great skill and will be difficult to execute unless by a pilot well practiced in the maneuver. 
2. The steep frontal attack and the side approach are not only difficult to execute and rather ineffective, but the risk of being damaged is great.

III. Summary of Fxperiments.
A. Participants
YOKOSUKA Air Group:       16 Zero fighters, 2 RAIDEN 
301st Air Group:                     16 Zero fighters, 2 RAIDEN
IV. Results
1. Essentials of basic approaches: Appendix #1
2. Attacking in formation: Appendix #2 
3. Deflection (angle) firing: Appendix #/3 

Appendix #1
Essentials of Basic Approaches against Large Planes
I. Head-on Attacks from Above and Below
A. Essentials of execution.
1. Angle of attack
2. Firing range: 800-300 meters
3. Deflection (Angle) firing:
The deflection is as shown in the annexed tables
4. Recovery
Whether attacking head-on from below or above, you should fly on opposite course, just clearing the enemy plane. If necessary, slip off to one side quickly to get out of the effective range of the enemy's guns. In doing this your angular speed relative to the enemy plane will be very great, rendering the enemy's fire ineffective. 
When a second approach is necessary after recovery, you must stay 1000 meters or more laterally from the enemy plane (outside the effective range of his guns).

B. Precautions 
1. There is a general tendency toward increasing the firing range. You should pay attention to the determination of the firing range, in order to avoid long range firing. During the experiments made by the YOKOSUKA Air Group, errors were made in estimating the 1400 meter maximum (TN: firing) range and 1000 meter maximum breakaway range. 
Because gunnery training has been carried out with sleeve targets, the firing range against real targets becomes excessive, as the target seems larger and the tension of actual combat predominates. Consequently, a medium attack plane should usually act as the target for photo-firing or simulated attacks. Or permanent targets the size of a large enemy plane may be laid out on the ground, so that planes returning from gunnery practice can make simulated strafing attacks. In any case, there must be a refinement in the judgment of firing range. 
2. To roll and turn directly in front of the enemy plane during your breakaway, while concentrating on the next approach, is very dangerous. This is because your angular speed in relation to the enemy plane is very small during a turn, and because your plane appears to be at a standstill for a moment. You present a large target to the enemy gunner, and cannot see his plane yourself; in other words, you're a fine target. Furthermore, during training the chances of a crash in mid-air are great.
3. When executing deflection (angle) firing during a head-on approach from above or below, it is easy to err in the direction of deflection, so care is required. 
4. In a concentrated attack the SHOTAI should be slightly more open than in patrol formation and should send in its four planes on successive attacks from directions differing by a small angle. 
II. Overhead attack. 
A. Essentials of execution. 
1. Approach and turn.
Your lateral distance from the enemy plane when making a frontal approach with an altitude advantage of 800-1000 meters should be small. When the target appears below and in front of you at 30° to 40° (target speed 250 knots), roll over with a half slow roll, keeping your sight on the target after the turn. If, imeediately after rolling over, you nose your plane down too much and withhold your fire, the target will then be beyond your guns, and the extreme difficulty of maneuvering to counter this will make effective attack impossible. On this account, it is necessary to keep the target in the sight from the moment of roll-over and to aim, maintaining a fixed lead. 
3. Firing range: 600-300 meters. 
Air speed is about 280 knots within firing range and about 325 knots at the break-away, but there is no need to fear for the strength of the airframe. (Air speed reaches 330 knots only after the plane has dropped 2500 meters following the roll-over, with the engine at full throttle. Terminal velocity is 340 knots.)
4. Leading your target and sighting. 
Although we rely on deflection (angle) firing, "leading" a target with the sight in present Zero fighters is impossible if the target speed is fast. Hence, the pilot's seat has been fully raised and your firing is sighted along the middle of the cowling. When this is done, the deflection is 6° - 7° (there is some variation depending on the fuselage).
5. Recovery.
When finished firing, continue diving to increase your angular speed to its maximum while within the enemy's effective firing range; then quickly retire out of effective range.
6. Repeated attacks.
After retiring out of effective range, nose your plane up slowly for another approach. With an altitude advantage of 5000 meters at a distance of 2000 meters, loop over and attack. If your lateral distance from the target is kept as slight as possible when starting your run, it will be easy to get lined up with the target's flight path and your attack will be facilitated.

B. Precautions.
1. Never make a flat diving attack. If you should fall behind the target after rolling over, give up the attack completely and recover as soon as you can. (Although it is better to continue diving after firing and then recover, a recovery above is possible when you still have considerable altitude advantage immediately after your roll-over, and when there is no fear of being under effective fire.) In attacks at an angle less than 45° your angular speed relative to the enemy plane is small, and the chances of your being damaged are great.
2. When holding your sight steady and making a persistent close-in attack, caution is required; your initial angle of attack must be good, or else it will rapidly flatten out as you close to firing range. You must concentrate on sighting and on the abrupt reduction in diving angle which accompanies your closing to firing range.
3. After rolling over and during your approach, you should constantly maintain the position you desire relative to the enemy. A "waiting attack" (MACHIUKE KOGEKI) is dangerous, since it is very likely to cause a mid-air crash.
4. A concentrated attack by a SHOTAI is rather difficult; consecutive strikes by BUNTAI at close intervals is more effective. In the formation for the latter approach there should be 30 meters distance between each plane, about 100 meters distance between BUNTAI, and about 300 meters distance between SHOTAI.

Reference data:
Observations made from a medium attack plane on an attack by 8 Zero fighters against 3 special training Type 96 land attack planes, 6-7 January 1944.
1. Overhead approach.
a. It is impossible to direct your MG's against a steep overhead approach, and firing with sights (SHOJUN HASSHA) is difficult as well. It is also difficult to fire on planes on opposite course and with an altitude advantage of about 1000 meters when they roll over, since they are at extreme range and will go into a steep dive immediately after rolling over. Because of the target's speed of movement gained from its fast dive, there is only a moment to fire lefore it breaks away.
b. It is easier to fire on those planes whose delayed run-in makes them fall behind or enter a shallow dive. Those who attempt close pursuit are similarly easy targets. In ceneral, the tailman ( ) of a SHOTAI has a tendency to be "pulled flat". 

2. Head-on approach.
During an enemy plane's approach from opposite course, its movement is slight, making it an easy target for the defending gunners. It is almost impossible, however, to fire on planes which continue on opposite course and recover above; they retire beyond firing range. It is easy to fire on planes which roll over in front of their target, especially on those which recover in inverted flight.

Appendix #2

Formation Attacks on Large Planes 
(Account of Experiments) 

I. Dates and Place. 
From 10 January 1944 to 13 January 1944. 
II. Personnel and Planes Participating. 
YOKOSUKA Air Group fighter personnel (16 Zero type carrier fighters) 
301st Air Group fighter personnel (16 Zero type carrier fighters)
III. Plan
A. Organization.
Force A    (9 Type 1 land attack planes 
                 (12 Zero fighters
Force B     20 Zero fighters
B. A combat air patrol of fighters would intercept some bombers with direct escort fighters (trying primarily to shoot down the large planes at one crack with a steep overhead approach), and the results of the attack would then be studied.
IV. Account and Comments. See annexed tables.
V. General Comments.
Since this experiment was carried out with a very small force and covered only one-phase of attack methods, there is still much room for further study. 

A. In addition to direct escort fighters, a strong diversion unit should be attached to the bomber interception unit.
B. The escort fighters should be disposed to provide protection against overhead attacks by enemy fighters approaching on opposite course. In addition to the usual direct escort disposition one unit (TAI) should be stationed 2000 meters in front and 1000-15000 meters above the attack plane unit.

Formation attacks on Large Planes (4 planes to a SHOTAI)
1. Formation Plan
Execute Weaving (BARIKAN UNDO)
2. Account
At 1310 the KISARAZU Air Group took off and gained altitude. The altitude of land attack plane unit was 2000 meters. The direct escort unit, taking position as shown above, proceded with a weaving maneuver.
The enemy was sighted at 1314, 6000-8000 meters distant.
When Force B's land attack plane unit attacked, Force A's direct escort unit had dropped too far back from its direct escort position to repulse the steep overhead approach of Force B's fighters in time. Although A's direct escort unit was directly above the land attack plane unit, the point where B's planes rolled over was 1500-2000 meters forward of it, so that A's planes were outdistanced and of no use in stopping the attack.
More study was needed on the disposition of direct escort units (cf. second trial). Since A's planes peeled off prematurely, B's patrol unit was late in assuming patrol formation. Tryout of a diversion unit in particular was impossible. (In the second trial, allowance was made.)

a. Some planes made shallow attacks because their roll-overs were poorly timed or executed too close together.
b. Whereas many planes did not get in the vertical plane of their target, they should have been as directly above and behind it as possible. CHUTAI and SHOTAI leaders needed more practice in the approach and run. (In selecting a target it is preferable to attack the wing-men first.)
c. Some pilots made poor recoveries. (They recovered by pulling out above.)
Break-away from the enemy after an attack should be rapid. (The superior speed achieved in the dive should be used in the break-away, so that the enemy direct escort fighters cannot jump upon you.)

Saturday 26 October 2019

CINCPAC - CINCPOA Translations - Nakajima J1N1 "Gekko" (Irving)

This is the first installment in a new series featuring primary source material we recently located in the National Diet Library
Since our current contest is about "Japanese Night Fighters", in this posting, we present a 14-page document regarding the installation of upward and downward cannons on the Navy Type 2 Reconnaissance Aircraft or Nakajima J1N1-C.

First, here's what Wiki has to say:
"In early 1943, Commander Yasuna Kozono of the 251st Kōkūtai in Rabaul came up with the idea of installing 20 mm cannons, firing upwards at a 30-degree angle in the fuselage. Against orders of central command, which was skeptical of his idea, he tested his idea on a J1N1-C as a night fighter. The field-modified J1N1-C KAI shot down two B-17s of 43rd Bomb Group attacking air bases around Rabaul on 21 May 1943."

And the report:


Item No. 9311, page 1. 
Source: Unknown. 
Subject: Fighter Unit, YOKOSUKA Air Croup: Reference Notes on Upward and Downward Inclined Fixed 20 mm MG's for Type 2 Land Recce Plane; dated August 1943; 14 pages, mimeographed. 
Editor's Note: 
The installation described in this important document, issued by the tactical research center of the Japanese Air Force, became standard on Japanese night fighters in the latter part of 1943. The document has previously been summarized and commented upon in "WEEKLY INTELLIGENCE" Vol. 1, No. 2, 21 July 1944. The arrangement of inclined cannon described in it represents a modification of "Irving's" armament, replacing the remote controlled after-turret guns found to be unsatisfactory for either day or night fighting. In "WEEKLY INTELLIGENCE" Vol. 1, No. 8, 1 September 1944, two photographs confirm and amplify the documentary evidence. Of interest is the fact that the 20 mm fixed nose cannon is retained. 
Military - Very Secret (GUNGOKUHI)                                          Fighter Unit, 
Copy #7 of 50                                                                 YOKOSUKA Air Group 
                                                                                              August 1943 


I. Inclined Fixed Machine Gun Installation 
II. Electric Firing Circuit 
III. Pneumatic Charging System 
IV. Rules for Bore Sighting 
V. Firing Tactics and Battle Lessons 

I. Inclined Fixed Machine Gun Installation 
1. As proposed by Commander KOZONO, all of the initial armament of the Type 2 Land Recce Plane was removed from the fuselage and it was equipped with 2 upward inclined and 2 downward inclined 20 mm Mark 2 fixed MG's (100 round magazines) as described below: 

(2) The machine gun installation is virtually fixed; and slight adjustments can be made in the rear mounting sufficient to correct errors in the installation. 
(3) Method of harmonization: 
The machine gun and the sight are completely harmonized along parallel lines by the ABUNE (TN: phonetic) water level (TN: sight). The methods of correcting the sight, in accordance with the particular aerial combat conditions, and the harmonizing and correcting of sights so as to orient the line of sight to the center of the shell's impact in accordance with the results of actual aerial firing in the anticipated aerial combat are still in process of investigation. 

V. Firing Tactics and Battle Lessons 
(1) The relation between the speeds of the two aircraft and the point of impact of the MG shell: 
(a) The rate of fire of the 20 mm Mark 2 machine gun is 480 rounds per minute (8 rounds per second) and so if the speed of the plane is 250 knots, the shells will hit as follows: 
(b) Stationary land target - 1 shell every 16 meters. 
(c) Against a target on the same course at the same speed - all shells will hit at the same point. 
(d) If your speed is 250 knots and that of the enemy plane is 230 knots on the tame course, your hits will be 1.25 meters apart on the target. 
(e) If the planes are both flying at 250 knots in opposite directions, your hits will be at intervals of 36 meters. 
(f) The above figures are based on one machine gun, and since this plane has 2 machine guns firing in the same direction, each shot puts 2 rounds within the above spaces. 
(g) In accordance with the above, the most advantageous attack tactics for this plane are obviously to pursue the target on the same course and fire while keeping it continuously in the sights. 

(3) Battle Lessons 
In April, 1943, two planes of the 251st Air Group were equipped for the first time with lower guns at an angle of 40 degrees and upper guns at an angle of 30 degrees. In May, 1943, they went out into a combat area. We select battle lessons which can be examined below. 
(a) While on night patrol on 21 May 1943, at about 0237 an enemy large model plane was discovered at an altitude of 2500 meters, our altitude being 2,000 meters. We closed to a firing range of 300 meters. One burst by the upper guns started a fire, and one burst by the lower guns shot it down into the sea. The upper guns fired 30 rounds, and the lower guns 10 rounds. 
(b) The same night at about 0328, seeing four parachute flares dropped from above the clouds, we discovered an enemy plane. The upper guns, in two bursts, shot down an enemy B-17. The upper guns fired 140 rounds. 
(c) After that, the same air unit using a total of nine planes shot down five enemy planes (two of them unconfirmed) out of a total of 45 large model planes which conducted four night raids between 1 June and 15 June. 
(d) That it is profitable (to use) this plane as a night fighter is confirmed by the above battle results. By gradually increasing the number of planes, notable results will soon be achieved. 
(e) The following opinions are presented in accordance with subsequent actual results: 
1. It is desirable to install both the upper and lower guns at an angle of 30 degrees. 
2. It is necessary to increase immediately the number of rounds of ammunition carried. 
3. Since the Type 2 land recce plane is too slow to repulse daylight attacks, we are planning to install this tape of armament on the Type Zero land recce plane or possibly on the Type 2 carrier recce plane. Since the windshield is cut of curved glass and it is difficult to see the front sight of the upper gun, make this part of flat glass. 
4. It is necessary to install inclined fixed machine guns in single seater fighters. 

According to "Moonlight Interceptor" by Robert C. Mikesh & Osamu Tagaya, the 251Ku aircraft was flown by "Superior Flight Petty Officer (SFPO)" Kudo Shigetoshi in the pilot seat and "Lt. (jg)" Sugawara Akira.
The two B-17s  were flown by Major Paul I. Williams (his bomber was named "Honi Kuu Okole" Hawaiian for "Kiss my ass", s.n. 41-9244 ) and Capt Joseph W. Geddes (his unnamed bomber had s.n. 41-9011) of the 64th Bomb Squadron.

Wiki continues:
"The Navy took immediate notice and placed orders with Nakajima for the newly designated J1N1-S nightfighter design. This model was christened the Model 11 Gekko (月光, "Moonlight"). It had a crew of two, eliminating the navigator position. Like the KAI, it had twin 20 mm Type 99 Model 1 cannon firing upward in a 30° upward angle, but added a second pair firing downward at a forward 30° angle, allowing attacks from above or below. This arrangement was effective against B-17 Flying Fortress bombers and B-24 Liberators, which usually had Sperry ball turrets for ventral defense. The Gekko's existence was not quickly understood by the Allies, who assumed the Japanese did not have the technology for night fighter designs. Early versions had nose searchlights in place of radar. Later models, the J1N1-Sa Model 11a, omitted the two downward-firing guns and added another 20 mm cannon to face upward as with the other two. Other variants without nose antennae or searchlight added a 20 mm cannon to the nose."

Thursday 24 October 2019

Japanese Aircraft Online Model Contest 013 - ALEX RODIONOV

Kit: Yokosuka P1Y1-S Ginga (Frances)
Manufacturer: Hasegawa
Scale: 1/72
There were almost no improvements. Used Gunze paints.
The plane belonged to the  302 Kokutai at 1945.

- Alex Rodionov, Russia -

Tuesday 22 October 2019

Japanese Aircraft Online Model Contest 013 - DAN SALAMONE #2

1/48 A6M5 from Hasegawa. Gunze lacquers used for all the painting. Built out of the box, except the decals came from an aftermarket sheet.

- Dan Salamone - 

Sunday 20 October 2019

Japanese Aircraft Online Model Contest 013 - DAN SALAMONE #1

1/48 Fine Molds Judy nightfighter, Yokosuka NAG. Painted with Tamiya and Gunze paints, opened canopy and used vacform parts. I built this in 2004, and remember that the fit left a lot to be desired but was a fun project anyhow.

- Dan Salamone -

Friday 18 October 2019

Japanese Aircraft Online Model Contest 013

ARAWASI would like to invite you to our thirteenth online model contest.
Theme: "Japanese Night Fighters"

Submissions: Send as many photos as you like of your model and accompanying information to or 
At the very least please send: your name and country, model scale and kit maker. Your entry will be posted very soon. You can enter the contest with more than one model in any scale.
If you decide to start a model for our contest you can send work-in-progress photos.

Voting: you can vote for each model from 1 to 10 either by leaving a comment on each entry or by sending an email to the above addresses. No anonymous votes will be taken into account (nicknames are ok). The model with the most points wins.

Deadline: December 31 (but it can be extended) 

Prizes: The winner will receive a book and a kit from our on-line store, free of any charge, courtesy of Arawasi.

*The theme for the next online model contest is "..." (leave a comment with suggestions) and will start from January.

Monday 14 October 2019

IJAAF & IJNAF photos & more

Another photo recently on sale on the Japanese ebay, featuring a Kawasaki Ki-10 "Perry" after a landing mishap.

Unfortunately the unit marking is not visible and there was no other information about place, time etc. The stamp on the top right reads "gokuhi" (top secret).

Sunday 6 October 2019

Gifu Army Flying School - video

A video from the NHK collection dated March 1, 1944. 

A number of aircraft types can be seen starting with at least two Mitsubishi Ki-51 "Sonia" and two Kawasaki Ki-48 "Lily".

And finally a Mitsubishi Ki-46-II "Dinah".

The tail markings of the aircraft indicate that they belong to the IJAAF school at Gifu.
The Gifu Army Flying School was organized in August 1940 at Kakamigahara, Gifu Prefecture. It was disbanded in March 1942. A year later, the Gifu Rikugun Koku Seibi Gakko (Army Air Maintenance School) was organized based at Kakamigahara with three kyoiku-tai (training units).
The tail marking of the unit is depicted below on a Tachikawa Ki-36 "Ida" by Zygmunt Szeremeta and was first published in our Eagle Eye #1.
Below is a close up on the tail of the "Dinah" in the video.
The time and the mention of "maintenance" in the naration indicates that the short clip was shot at Gifu Rikugun Koku Seibi Gakko.