Today we present a translation we did of an article featured in Maru Mechanic #37 on the Type 3 Fighter or Kawasaki Ki-61 "Hien" (Tony) written by Sergeant Major Koyama Susumu who served with the 68th Sentai. Enjoy.
Sg Major Koyama first graduated from Kumagaya Aviation School on December 1942; 10th class of the Shonen Hikohei programme. Then he was assigned to the 246Sentai for a four-month fighter training flying Nakajima Ki-27 "Nate" and then went to Akeno Aviation School to train with Hien. The first month in Akeno was spent training with Ki-27 and Nakajima Ki-43 "Hayabusa" followed by a two-month training with Ki-61. He clearly remembers that the very first Hien he flew had serial number 103, the first mass produced Hien, and the first to be given to a school. He trained with six Hien in Akeno, serial numbers 103, 106, 107, 127, 132 and 189. He explains that when a pilot is sitting in the cockpit of the Ki-61 he has the impression that the nose is very long but nevertheless the aircraft offered good overall visibility.
On a typical training day the ground crew climbed on the aircraft wing, turned the starter handle and after shouting “switch on” a ground crew member presses the clutch button located right above the starter handle. When the button is pressed the liquid cooled engine immediately comes to life with a distinctive “bari, bari, bari” sound. The feeling is completely different compared to the "Nate" or the "Hayabusa". After checking the instruments the pilot starts taxing until the take off point. One of the peculiarities of the liquid cooled engine is that after long taxing the engine gets overheated very easily reaching temperatures higher than 90 degrees and steam starts rushing out from the water pressure valve like a whale blow. Instructors advised to ignore this steam and proceed with the take-off. This problem was common with the Hien so very often crews poured water over the engine to cool the planes down when on the ground. Gradually gathering speed, your body pushed back to the seat, you pull the stick a bit and the plane leaves the ground very smoothly. The steam stops right after take-off.
The engine of the Hien was very easy to start posing absolutely no problems. Even without the help of ground crew the pilot could easily start the engine with the same procedure. [Here's a reply to those who wonder how the pilots quickly started their planes without the use of starter trucks]
New orders and aircraft
After Akeno, an order arrived that he and four other pilots studying together in Akeno were to get new aircraft and to proceed to Wewak in New Guinea. For this, they all went to Kakamigahara, Gifu prefecture at the Kawasaki factory located in the same prefecture where brand new Hien were standing in line, their duralumin sparkling in the bright sun. Upon receiving a note with the number of the aircraft he was assigned to, number 388, he proceeded to locate it. After he found it he started the engine, checked if everything is okay and then taxied in front of the aviation arsenal hangar. At that point the ground crew applied a white line and madara (spotted) camouflage on the fuselage and Koyama asked them to allow him to paint his own aircraft; applying the number 388 on the tail.
The pilots returned to Akeno for further training including aiming adjustment for the 12.5mm cannons and the 7.7mm machine guns. But as far as Koyama remembers the 388 was still equipped with 7.7mm machine guns on the wings.
On September 18, 1943 the five with Commander Hibino took off from Gifu but Hibino and two others were lost due to bad weather. Two days later with a new commander and pilots they started again and all finally arrived at Clark airfield in the Philippines four days later after stopping at Nyutabaru in Miyazaki prefecture and Taiwan. On September 23, took off from Clark reaching Davao first. Koyama explains that the airfield in Davao was very dangerous because the lowest point is in the middle of the airfield. His group of five was ordered to land from South and land at a specific point of the airfield. They all did it without any problems but some aircraft from another unit that tried to land after them flying Hayabusa overshoot the airfield and crashed. The next day he reached Menado (present day Manado) in the Celebes islands (present day Sulawesi). On the 26th the group took off from Menado but encountered heavy squall and had to land at Soan [we were unable to locate this airfield], wait for an hour and then proceed to Babo in New Guinea. Babo was also a very dangerous airfield with a sharp inclination and a cliff right after that. So no matter what direction you tried to land you were always sideways and in constant danger to fall off the cliff.
The next day they finally reached Wewak. The flight to Wewak is 7-hours long and the plane had to be fuelled to the brim and fitted with two 200l drop tanks. They all flew their aircraft without any mishaps.
An excellent map showing the various Japanese and Allied airfields.
Air combat over Wewak
Koyama remembers that while in Wewak the Hien he flew had the fuselage fuel tank removed because there was always the danger of exploding if enemy bullets hit it.
One day he was flying with the group of First Lieutenant Inoue on air patrol. After take-off he test shot his guns and gathered with the other seven aircraft at an altitude of 6000m. Inoue and the chutai-cho (squadron or flight leader) fluted their wings and they all got into battle formation. As many as 400 enemy fighters and bombers could be seen in an Eastern direction first as glitters, then black spots gradually becoming larger. In the beginning only 2-3 aircraft were visible, then about a dozen then more than 70-80 aircraft. The Hien group turned to the left of the enemy formation and started gaining altitude. When the enemy aircraft saw them a small rain of drop tanks was seen falling to the ground. A few seconds later the battle started and the Hien pierced the enemy formation. Koyama got himself stuck behind M. Seg Matsui and with the other aircraft of the 2nd buntai (squad) turned and approached from the left but were followed by the enemy aircraft finding themselves flying altogether in a circle. Suddenly a hail of bullets started falling in front of the Hien group. Koyama pulled the stick to his belly and stepped on the foot bar. Although the very sharp turn forced high Gs on him and he started to blacken out he could still see that the buntaicho (squad commander) was able to turn left and avoid the bullets too. Suddenly without him doing anything his aiki (beloved aircraft) turned right, nosed down and looked like it was going to crash. He immediately corrected his position always aware of his surroundings. During that time he was separated from the Hien group and he recalled that during training there were incidents where the Hien stalled when the stick was pulled hard. While he was trying to reposition himself he saw two enemy fighters in front of him, diving towards him. They were P-47 Thunderbolts. He was able to avoid them unscathed at an altitude of 6000m. Taking a look around him he could see no enemy planes but 1500m below him there was fierce fighting taking place. Lower to his left a single Hien was pursued by four P-40s. It was Inoue’s plane and he decided to attack. Hien’s diving speed is amazing and he immediately came to within 100 meters from the enemy planes. He started shooting with his 12.7mm cannons and immediately the last P-40 caught fire and was shot down. The other three didn’t notice that the last plane was lost and continued pursuing Inoue. Koyama dove and climbed and placed himself behind the enemy planes. It took 70-80 bullets and one more enemy plane exploded and fell. The explosion was noticed by the other enemy pilots who stopped pursuing Inoue, dove and escaped. After that he shot down a P-47. The battle was so intense and confusing that only when he returned to base he was able to count no less than 29 bullet holes on my plane. The Hien had an armoured protection plate behind the pilot and on his plane they found one 12.5 bullet stuck on the headrest, five more on the back plate and two inside the parachute. He was scratched on his left foot by a bullet fragment and he still carries this scar to this day.
More combat and the 20mm Mauser cannon
One day around November 1943, 10 Hien and two transport aircraft arrived to our base. On the wings of the Hien a metal tube I had never seen before was sticking out. It was the 20mm Mauser cannon. The pilots were later gathered to be shown the new gun and test fire it. I wanted to fly a cannon equipped Hien but I was too young a pilot to give me one. In 1944 when the pilots, the aircraft and the supplies were few, one day I flew alone above the base with a 20mm cannon equipped Hien. At an altitude of around 500m, I got a radio message from the base about a large size enemy plane approaching the base. I climbed to 6000m, flew to an eastern direction and started searching for the enemy plane. A few minutes later I saw a B-24 flying over a mountain east of the airfield. I checked if there were other enemy planes in the area and started attacking the enemy plane from front and above. The B-24 shoot me back but with growing speed from my frontal dive I shot the cockpit of the B-24. I bunked to the side to avoid hitting it, turned around and climbed. I looked to see if I had hit B-24 but I hadn’t and tried again a few times. Suddenly one of my 20mm bullets hit the bomb bay of the B-24 and a huge explosion disintegrated the bomber. Probably one of my bullets hit one of the bombs. It was the only large size enemy plane that I was ever able to shoot down.
The 20mm cannon was so powerful that if a bullet hit the aircraft’s main wing spar it could cut the wing.
Although there were many losses due to mechanical problems and emergency landings, the Hien was a reliable aircraft when the engine was in good condition. It was sturdy and very fast and the originally installed speedometer was sometimes broken because the plane could reach speeds higher than the max 780km/h it indicated. Later speedometers indicated max speed of 1000km/h.
The maintenance crew in my unit did their best and I definitely owe my life to the bullet-proof armour my unit didn’t remove. If I was flying a Hayabusa I wouldn't have survived the War. In my opinion the Hien was a really excellent aircraft.