Nakajima Ki-84 Hayate / FRANK
1943
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Nakajima Ki-84 Hayate / FRANK

Best of all Japanese fighters available in quantity during the last year of the war, the Nakajima Ki-84 Hayate (gale) not only possessed a reasonable performance but (unusual among Japanese aircraft) carried a powerful armament capable of knocking down the heavily armed and armoured American bombers. Not flown in prototype form until April 1943, the Ki-84 met with immediate approval by Japanese army air force pilots, but was subjected to lengthy service trials which undoubtedly delayed its introduction to combat operations. Production got under way at Nakajima's Ota plant in April 1944, pre-production aircraft having equipped the 22nd Sentai in China the previous month. Immediately afterwards 10 sentais of the Ki-84-I, codenamed 'Frank' by the Allies, were deployed in the Philippines to confront the advancing American forces. In an effort to accelerate production of the excellent new fighter, Nakajima opened up a new line at its Otsonomiya plant, and as Boeing B-29 raids began to take their toll of Japanese cities a new 'bomber destroyer', the Ki-84-Ic, was produced with an armament of two nosemounted 20mm cannon and two wing-mounted 30mm cannon. Some measure of the importance attached to the Ki-84 may be judged by the fact that in the last 17 months of war 3,382 aircraft were completed, this despite the tremendous havoc wrought by the B- 29 raids and the fact that, owing to such damage at Musashi, Nakajima's engine plant had to be transferred elsewhere.

Nakajima Ki-84 Hayate / FRANK


Specification 
 MODELKi-84
 CREW1
 ENGINE1 x Nakajima Ha-45, 1416kW
 WEIGHTS
    Take-off weight3890 kg8576 lb
    Empty weight2660 kg5864 lb
 DIMENSIONS
    Wingspan11.24 m37 ft 11 in
    Length9.92 m33 ft 7 in
    Height3.39 m11 ft 1 in
    Wing area21 m2226.04 sq ft
 PERFORMANCE
    Max. speed631 km/h392 mph
    Ceiling10500 m34450 ft
    Range w/max.fuel2168 km1347 miles
 ARMAMENT2 x 20mm cannons, 2 x 12.7mm machine-guns, 2 x 250-kg bombs

3-View 
Nakajima Ki-84 Hayate / FRANKA three-view drawing (752 x 1111)

Comments1-20 21-40
Ron, 22.05.2014

Corrections:
The Ki 84-Ic added 2 wing-mounted Ho-155 30 mm not 37 mm cannons (Ki 44-IIc), to augment the 2x20s in the cowl. It was barely in service but not likely in combat.

Also, if we factor in the 120g AP round that not all sources do, the 4x20 mm Ho-5 salvo for the Ki 84-Ib was 3.8-4.3 Kg/s!

The standard mixed gun Ki 84-Ia salvo was somewhere over 3 Kg/s even without that heavier AP cannon shell in the ammo belt composition.
My math is only in the ballpark considering that the data
reflects the degradation of the Ho-5 as the war ended.
When it was new it was a better contender.
The Monogram publication by Leszek A Wieliczko includes the 120g AP with the other rounds (Pg 68).

Ron, 22.05.2014

The Ki 84-Ib with the 4x20s (Ho-5) was something over 94 built, while the -Ic was far fewer. That would still be decent firepower without the 37 mm cannons, with 4 ho-5s of the -Ib:
Upwards of 3.2+ Kg/sec. dispite over 50% synchronized penalty and g/round on the light side. The 750-850 ROF per Ho-5 was cut to 400 each, firing through the prop. The muzzle velocity had degraded from 820 m/s to about 700-750 toward the end. So, more than 2 is better even if 4 cannons are perhaps effectively 3. At least the cowl guns are long range, while fighters like the Raiden and Shiden have 4 cannons all wing-mounted limiting them all to convergence range. Range was 900 m for the Ho-5 cannon.
APT was 112-113g and had 7g of Tracer. Some AP was 120g.
HEI was only 79g and had 4g of HE and 4g of Incendiary.

The Ki 116 Hayate was tested with the lighter 1500 hp engine used by the Ki 100, and still managed 384 mph top speed and 497 mph dive redline like the Ki 84. It was about 1,000 lbs lighter than the standard Ki 84 and had a longer nose to maintain cg. Agility and reliability were much improved as expected. Alas, it was too late for production.

Ron, 10.10.2013

Good match for the P-51 in a dogfight.
It was right up there with the best from Japan.
A 20-mm projectile from a Frank was found in the wreckage of Tommy McGuire's P-38L. The Oscar that was also in that fight did't have cannons. 4 P-38Ls vs 1 Ki 43 and 1 Ki 84. Scratch 2 P-38s. I know the cover story is a little different. The Ki 84 was new at the time and was initially confused with earlier less deadly Nakajima fighters. This gave the Frank an added advantage. You can't say that about the Mitsubishi A6M and J2M or the Kawasaki Ki 61 and Ki 100.
Another advantage was the larger numbers the Frank enjoyed compared to other newer fighters from Japan like the J2M, Ki 100, or even the NIK 'George'.
It also was faster in level max speed than these were. In fact faster at some altitudes than Allied fighters too.

percy, 03.12.2012

there were some problems with the Bristol Centuras air craft engine but these were ironed out and as it turns out these engines had one of the longest intervals between major overhauls ,how ever these engines may have been slightly more difficult to service and maintain than the conventional poppet valve radial engine .the British authorities obviously thought the 20% gain in power was worth the extra effort.A KI 84 Frank fitted with one of these engines would be superior to all allied and German contempory fighter planes

Ron, 26.11.2012

I do know the Sea Fury was active in the Korean war but didnt the sleeve valve tend to distort? Thus I believe serviceability was an issue.

percy, 01.10.2012

Ron ,the Hawker Tempest Mk 2was used very late in the last war,mainly to distroy the v1 flying bomb sharing these duties with its sister ,the tempest Mk 5.THE Mk 2 was powered by a colossal Bristol centuras radial engine capable of producing over 3ooohorse power and because this engine used sleeve valves this engine had a smaller diameter than any convential radial of the same power.this allowed the tempest Mk2 to retain the slim lines of the Mk5 with no increase in frontal area ,so the Mk2Tempest was not only faster than redoubtable Mk5 but its air cooled engine was less vunerable to battle damage .If the Tempest Mk 2s engine could be fitted to the Hayate then this remarkable Japanese fighter would be the superior machine

percy, 01.10.2012

Ron ,the Hawker Tempest Mk 2was used very late in the last war,mainly to distroy the v1 flying bomb sharing these duties with its sister ,the tempest Mk 5.THE Mk 2 was powered by a colossal Bristol centuras radial engine capable of producing over 3ooohorse power and because this engine used sleeve valves this engine had a smaller diameter than any convential radial of the same power.this allowed the tempest Mk2 to retain the slim lines of the Mk5 with no increase in frontal area ,so the Mk2Tempest was not only faster than redoubtable Mk5 but its air cooled engine was less vunerable to battle damage .If the Tempest Mk 2s engine could be fitted to the Hayate then this remarkable Japanese fighter would be the superior machine

Ron, 15.05.2012

The Ki 84 was tested against the Fw 190A-5 in Japan and the Focke-Wulf had quicker dive.
I say quicker instead of faster because the terminal dive speed isn't the same as dive acceleration on the way there.
I welcome more info on this.
It's like the dive of the Ki 84 being better than the Ki 100 even though the maximum terminal speed is about 497 mph Ki 84) vs 528 mph (well built Ki 100) respectively.
The strength of the plane comes into play as well as the weight, power, drag, compressibility and so on.
It's not so simple as level maximum speed.

Ron, 27.04.2012

Percy, could you elaborate please.
I believe the Mark V was the only production Tempest in WW 2 action.

percy, 14.04.2012

the only allied fighter plale that was clearly superior to the japanese ki-84 was the hawker tempest mark 2

Ron, 09.04.2012

I ran across something about the Ki 84 from a Russian author.
I didn't realize the cylinder block had to be replaced during an engine overhaul after only a few flights! In fact EVERY flight the Ha-45 had to be cleaned and rebiult!
It's no wonder specially qualified mechanics were necessary to keep the fleet maintained and serviceable. Finally the model 11 was replace by the improved 12, then the 21, and then the 23 engine was much better but not as powerful, only 1900 hp. But high altitude was still trouble.
The turbocharged 2000 hp Ha-45Pu was too late.

Ron, 09.04.2012

Jim,
I believe so. I've seen a photo of a bare metal Frank with US insignia flying in formation with allied fighters including a Seafire. It could have been the one you speak of.

Jim Reynolds, 06.04.2012

Was the captured Frank ( that was in the Phillipines) repainted in US stars and bars ??? Thanks. Jim

Ron, 25.03.2012

Good work Aaron,
Now if we only we had that much on all the fighters, Oh and of course control harmony, turn time (wing-loading doesn't tell the whole story) and deg/sec roll rate, and stall, terminal dive speed, stall recovery and dive pullout (compressibility) ...etc. Maybe the mystery keeps us digging.

Aaron, 29.01.2012

Hey Ron are you still out there?
For Christmas my wife bought me the TAIC MANUAL No.1 on Japanese aircraft.
Mick Dunne, while the Frank could outclimb the average P-51D, it did not outclimb the P-51B when pushed to 75" engine boost pressure that was cleared in 1944 (about the time the Frank showed up).
For all those that are interested, the figures on the Ki.84 with the Ha.21 engine when it was properly constructed and maintained were:
2,040hp./7,940 lbs.combat weight/226sq.ft.wing area.
The following is SPEED mph/CLIMB fpm/TIME TO HEIGHT minutes:
362/4,275/S.L. 379/4,350/.8/1,000m. 389/3,890/1.65/2,000m.
389/3,570/2.6/3,000m. 388/3,590/3.65/4,000m. 414/3,610/4.6/5,000m. 426/3,350/5.7/6,000m. 427/3,250/5.8/6,098m. 426/2,870/6.8/7,000m. 416/2,280/8.25/8,000m. 403/1,720/9.6/9,000m. 387/1,175/10,000m.

wanshan, 21.06.2011

Only let down by dismal production standards at the 'wrong' end of the war!

, 21.06.2011

Nakajima Ki-84 Hayate / FRANK

Ron, 16.12.2010

The straight leading edge of Nakajima fighters helped initial climb and entering a turn, but dive was highly prone to buffeting and control loss approaching compressibility, from the shock wave. So terminal dive didn't quite breach 500 mph (only 496 or 7). Flight stability in a dive was thus inferior to the Kawasaki Tony, both inline and radial models (Ki 61/100) which did well over 500 mph. So level maximum speed advantage doesn't always translate to dive speed performance.

Ron, 09.11.2010

They should have kept the Ha-109 motor from the Tojo and split the Frank like the USSR did with the Yak-9U.The engine was unreliable at first so the early -9U was powered by the previous motor which was mature and still reached 420 mph.
If the Frank had 2 lines of power plant maybe it would have given up 10 or 15 mph with the less powerful Ha-109 but it would have been a much needed reliable Frank while the bugs got worked out of the new unreliable one. It could replace the role of the Tojo and Oscar early by cutting back on internal fuel or cut the ammo supply respectively for the interceptor or dogfighter roles. The Frank could have twice as many produced in place of Oscars and Tojos with their deficiencies. And the Frank with the reliable Ha-109 would have no drawbacks in 1943. It could still be as fast as most any Japanese fighter and out maneuver any Allied fighter and rival the Zero in production output. And if the newer Ha-45 beast couldn't be tamed, supe-up the Ha-109 or Ha-112 (of Ki 100 fame). These reliable motors were around since before mid-war with 1500 hp. Perhaps the Ha-112 is slimmer than the Ha-109, I don't know.

ore kimi no tame ni koso, 29.09.2010

The Frank was the more powerful fighter of IJA

1-20 21-40

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