Identifying the IJN Radar-equipped Kamikaze Pathfinders

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Mil-tech Bard
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Identifying the IJN Radar-equipped Kamikaze Pathfinders

#1

Post by Mil-tech Bard » 11 Nov 2016, 19:21

I am asking for help in identifying the Japanese radar equipped twin engine night fighter that was playing "pathfinder' for Japanese Kamikaze strikes -- and the units using them -- mentioned in the text excerpt below:

UG 1240 . N38 no. 28
NAVAL FIGHTERS NUMBER TWENTY-EIGHT
FR-1 FIREBALL
AND
XF2R-1 DARKSHARK
BY STEVE GINTER

PAGE 49 to 50
THE FIREBALL AND VF-66 AS REMEMBERED BY "WILLIE" SCHMALL

The CO of VF-66, LCDR Gray, was taking one or two of the best pilots from each of the returning squadrons, with the intention to get the Ryan into the fleet as quickly as possible. Sunny Fischer, my wingman, and I were both from VF-60, and we elected to go to VF-66. These combat experienced pilots formed the core of the squadron, and were supplemented by some green pilots right out of flight school. As it turned out, most of the combat proven pilots were only with the squadron a short while because as it turned out we had gone on our ten day pre-embarkation leave when they dropped the bomb. Our Exec was an on-the-ball guy and about six of us were immediately discharged out of San Diego.

I reported to VF-66 on 6 January 1945, where we spent most of our time flying the FM-2 Wildcat while awaiting receipt of our FR-1s. I didn't get my first flight in the FR-1 until 26 April 1945. Our objective was to get 22 aircraft from the Ryan factory across the bay, and to get out to the Pacific to deal with the Kamikazes. The fleet didn't have anything that could catch them except us.

The Japanese would have an experienced pilot we called a "Joker" fly in a twin-engined night fighter, and the "Clowns", which were the suicide pilots, would be down on the water. The "Joker" with his radar would snoop out the task force and tell the "Clowns" what direction and how far out the ships were. He would then return to pick up another load of "Clowns". The "Joker" was the one the Navy wanted to put out of commission, and there was nothing in the fleet that could catch him. To this end we were told that as soon as we got 22 fighters we were on our way. The objective of the Ryan was to sit on combat air patrol conserving fuel by just using the forward engine, and when you got a vector you could fire up the jet and use both engines to go after and catch the "Joker".


The earliest Ryans we had (double slotted flaps) were actually unstable at slow landing speeds. In your left-hand race track approach you had to hold top-stick and top-rudder because it kept wanting to roll over. This problem was solved by installing single slotted flaps, and by slotting the ailerons.

Squadron doctrine was to use both engines on takeoff. One day when I was leading a flight of four Ryans, we took off in formation, stood the aircraft on its tail, and rocketed straight up through the cloud deck of 9,000 feet. Upon where I got a call from the tower saying that if we continued those type of take offs, they would insist on instrument (IFR) clearances.
Tenatively, the "Joker" seems to be the Nakajima J1N1 Gekko (月光 "Moonlight").

I'd like some help in confirming that and identifying the IJN J1N1 equipped units involved in the Okinawa campaign, if any.

AKA it is quire possible that the "Joker" was identified in a ULTRA intercept as a future Japanese tactics, but I have too many Luzon, Iwo Jima and Okinawa AAR's that show repeated USN mentions of IJN/IJA radar planes leading Kamikaze's to radar picket ships to think that was the only source

Mil-tech Bard
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Re: Identifying the IJN Radar-equipped Kamikaze Pathfinders

#2

Post by Mil-tech Bard » 12 Nov 2016, 19:05

The following is my tentative tactical analysis of the J1N1 Gekko as "Radar pathfinder" at Okinawa --

Since the IJN Air Mark VI Model IV radar could trigger American Fighter Type III IFF without their knowledge, this plane was snooping the entire American fleet CAP disposition at Okinawa in real time. It's speed and most especially its endurance with drop tanks, allowed it to snoop this disposition. Then lead in repeated waves of Kamikazes echeloned behind it, all of whom were flying low, under American radar, and radio silent.

The J1N1 Gekko's radar electronic intelligence (ELINT) capability meant it could pop into and out of American radar coverage for feints, as it could also "Ride the nulls" as well as home in the strongest signals.

And note, 'riding the null' of a picket destroyer radar signal -- that is, flying the gaps in the radar coverage due to reflections from the sea -- did not preclude the ability to switch over to homing on fighter director VHF signals periodically while doing so.

The endurance and kinematic performance of the J1N1 Gekko plus the ELINT capability of the Air Mark VI Mod IV's radar, made it the perfect Kamikaze pathfinder. It reminds me a lot of the EF-111's tactics versus the 1980's era Soviet integrated air defense system (IADS).

NB: The US Navy at Okinawa was in an electronic warfare campaign, and it not only lost it. It's senior command staff during Okinawa was without a clue that it was in an electronic warfare fight to begin with. Not only was it true that "They didn't know what they didn't know." They didn't have a theater level radar intelligence organization (See MacArthur's Section 22) to catch what was happening and provide lessons learned.

Even when the centralized USN Radar intelligence picked up the J1N1 Gekko as "Radar pathfinder" pattern at Luzon and Okinawa via operational analysis months later. Naval Intelligence in DC still refused to believe that the Mark III IFF was compromised -- data that MacArthur's Section 22 provided to Naval Intelligence in DC in late 1944.


Mil-tech Bard
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Re: Identifying the IJN Radar-equipped Kamikaze Pathfinders

#3

Post by Mil-tech Bard » 12 Nov 2016, 19:07

Note that a background on US Naval radar intelligence is at this forum thread --

http://forum.axishistory.com/viewtopic. ... 3&t=220164

Mil-tech Bard
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Re: Identifying the IJN Radar-equipped Kamikaze Pathfinders

#4

Post by Mil-tech Bard » 02 Dec 2016, 16:16

Does anyne have a copy of Nihon Kaigun Yakan Gekigekisen" (A History of JN's Night-Fighter Units)* by Watanabe Yoji?

I'd like a run down of the J1N1 Gekko units in Japan and formosa during the Okinawa campaign.

Thus fat I've seen references to the 251st, 302nd and 322nd Kokutais as Gekko units.

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Re: Identifying the IJN Radar-equipped Kamikaze Pathfinders

#5

Post by Mil-tech Bard » 03 Jul 2018, 13:55

It seems one of the DD captains at Okinawa recognized the IJN Snooper/Pathfinder radar plane operational pattern I've been chasing through various after action reports. The USS Mannert L. Abele was near Okinawa when the fleet was arriving in March 1945 and covered two nightly retirements of the bombardment force at Okinawa as a fighter director destroyer.

Here is the source and what that USS Mannert L. Abele's captain said --


SECRET INFORMATION BULLETIN NO. 24
Battle Experience
Radar Pickets and Methods of Combating
Suicide Attacks Off Okinawa
March-May 1945
20 July 1945

http://www.ibiblio.org/hyperwar/USN/rep ... index.html


CO USS Mannert L. Abele comments and recommends:

1. This ship controlled combat air patrols during 4 days while in the target area prior to Love Day and during 2 nights while retiring with TF 54. No interceptions were attempted during daylight; two were attempted at night, resulting in merged plots but no splashes. The ship was taken under attack on both Radar Picket Stations #4 and #14. In each case the attacks were preceded by reconnaissance planes flying near the ship both the day before and also a few hours before the attacks. It is believed that this action by the Japanese is a definite indication of impending attack and it is strongly recommended that combat airpatrols be immediately furnished to ships thus warned.

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Re: Identifying the IJN Radar-equipped Kamikaze Pathfinders

#6

Post by Mil-tech Bard » 03 Jul 2018, 14:07

It appears that 7th Fleet took very seriously the threat of Japanese radar triggering it's IFF.

There is nothing similar in CentPac operational plans for Iwo Jima and Okinawa and the bits and pieces of the US Navy's PAC 70(B) Radar documents I've found don't have anything similar. This appears to be an artifact of MacArthur's Section 22 radar hunters in 7th Fleet.

See:

ANNEX "N" TO COMMANDER CENTRAL PHILIPPINES
ATTACK FORCE
OPERATION PLAN NO. 1 - 44
COMMUNICATION PLAN
NO. 4-44

http://www.ibiblio.org/hyperwar/USN/rep ... -44-N.html

Appendix 3 to Annex N Central Philippines Attack Force Operation Plan 1-44
RADAR PLAN AND RADAR REPORTING PROCEDURE.


11. IFF PROCEDURE.
For Surface Vessels, the following conditions of IFF may be ordered by OTC.

a.Condition HOW.

1.Radar Guard Ships have interrogator-Responsor, and Transpondor ready for instant use, but transpondor will be energized only in accordance with challenge procedure set forth in next paragraph.

2.All other vessels have Transpondor (BK or ABK) ready, but not energized.

b. Condition ITEM.

Same as conditions HOW, except Radar Guard Ships will have Transpondor energized at all times.

c. Condition KING.
All vessels have Transponders energized at all times. Use Interrogator-Responsor as necessary to identify contacts.

d. IFF Challenge Procedure.

1. Any vessel making an unidentified radar contact shall immediately report same in accordance with paragraphs 6 & 7 above. Vessel making contact shall interrogate contact as quickly as possible unless the appropriate guardship has in the meantime interrogated, and made amplifying report.

2. If IFF Condition HOW is in effect, the responsible radar guardship shall energize its Transpondor for a period of 30 seconds following a friendly response from interrogated contact, unless instructions to the contrary have been issued by OTC. OTC may prescribe additional energizing of Transpondor at discretion.

e. IFF Condition KING will automatically be assumed.

1. By the junior unit(s) when joining up with other ships or units in darkness or low visability.

2. Night or day when a melee develops.

f. Enemy Triggering of IFF.

There have been numerous reports that our ABKs have been triggered by enemy radars.
Should this be suspected, a headset will be plugged in the ABK (or BK) monitor jack. A note will be heard which represents the pulse repetition rate of the triggering source. Our own Interrogator-Responsors have a PRF which is never greater than 400 cps. Referring to paragraph 9 (d), it will be noted that the PRF of enemy radars capable of triggering BK or ABK (i.e., Mk. 1, Models 2 and 3; Mk. II Model 1 and Air Mark VI) are all believed to be greater than 400 cps. By this method it may be possible to determine additionally whether an enemy transmission is land, ship or air-based.

-- 11 --

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