Nakajima Ki-84 Hayate / FRANK
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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

 ENGINE1 x Nakajima Ha-45, 1416kW
    Take-off weight3890 kg8576 lb
    Empty weight2660 kg5864 lb
    Wingspan11.24 m37 ft 11 in
    Length9.92 m33 ft 7 in
    Height3.39 m11 ft 1 in
    Wing area21 m2226.04 sq ft
    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

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

Comments1-20 21-40 41-60
Jam, 08.03.2017

Ki-84 had 624km/h @ 6000m top speed (Japanese stated top speed at military power whereas the Germans, Americans and British stayed the top speed of their planes at War Emergency Power) with its first Ha-45-11 engine. At WEP you're looking at about 645km/h at 6000m with Ha-45-11.

Then in late 1944 the Ha-45-21 1990hp engine was introduced. The US TAIC report used this engine. However the TAIC report is just calculations. The drag coefficient is too generous when you compare the drag to the Japanese tests. Ha-45-21 Ki-84 had about 665km/h at 6000m at WEP top speed. (Not 687km/h that is stated in TAIC).
In late 1945 the Ha-45-25 engine came which had 2000hp and lost less HP as it gained altitude. At 6000m it would of gave the Ki-84 about 680km/h @ 6000m at WEP

ron, 02.06.2016

More detail on the 20mm Ho-5 cannon ammo (on fighters):

The fuseless black soft APT was 112.7g with 7g of tracer.

The hard APT was (118g) 119.5g with 7g of grn-white tracer.
It was black with green and white bands and fuseless.

The HEI 'incendiary' was 78.2g (82.5g);3.2g PETN/RDX;8.7g I.
It was black with a brass nose, fuseless.

The HEI 'explosive' was (65.2g) 77.4g; 3.4 RDX; 3.7g I.
It was black too, but fused.

Other ammo also used by IJAAF:

Medium APT was 116.7g (118.5g) and 7g red tracer.
It was black with a green band and fuseless.

A silver-grey HEI 'special incendiary' was (70.9g) 77.4g; with 0.4g RDX and 3.7g I. It had a 2 piece fuse.

The numbers in parenthesis come from converting (ounces vs) grains to grams. I favor grains since the OZs are more rounded off. It is curious how the results go back and forth though. I got it from the RAAF leaflet on scribd.

M/V slipped from 820mps to 700mps for the APT and 740 for HEI late in the war.

GUD, 17.03.2016


Ron, 27.12.2015

So if a 8300 lb Ki 84 can turn full circle in 17 seconds, what can a 7039 lb Ki 116 do?
17 is already A6M5 territory! In time if not radius.
It may approach Ki 43-IIIa turn performance. Who knows?
If I were an Oscar ace in 1945, I would petition for the
385 mph Ki 116 Frank!

Ron, 27.12.2015

853' radius turn time is 17 sec 360 deg left, 20 to the right. 236+ mph start.

Ron, 26.12.2015


"1.This plane can perform each special flight easily, it doesn't have any bad characteristics.

2.Quick turn or roll maneuvers (such as quick roll, spins, etc) would give bad effect on the plane so it shouldn't be performed.

3.Oil pressure will be zero when at inverted flight, so do not try the inverted flight.

4.When pulling up on highspeed, the acceleration have to be within 4G.

5.When trying the special flight, because of this plane`s characteristics, try to always keep the altitude and speed before starting.

6.Because for being kind to the engine, do it on 2600RPM when at training.

7.With exception for when deep (vertical) dive, elevator tab should be in cruise mode.

8.Spin characteristic is good, and it doesnt enter to bad spin. When you`re at the spin, it will stop immediately if you place all rudders in neutral position.

9.To perform a loop, start at the speed of 400km/h, 2600RPM, Manifold pressure (+)100mmHg.

10.The point for chandelle is same as looping.

11.To perform a Immelmann turn, start at the speed of 400km/h, 2600RPM, Manifold pressure (+)200mmHg.

12.When at upsending invert roll , from the speed of 350km/h, rise in the angle of about 80degrees, open the Manifold pressure till (+)100mmHg, when you reach 150~160km/h start them as the usual process.

13.To perform slow turnover, switch the "pitch lever"to 2600rpm and keep the speed at 250(300)km/h and start them as usual process. The altitude loss is about 900m and the speed when returning at horizontal would be about 400km/h

14.To perform quick turnover, switch the "pitch lever"to 2600rpm and keep the speed at 250(300)km/h and when pulling the stick enough to the left(right) back, simultaneously stomp the rudder to left(right) enough and heading the nose swiftly to lower side, try not to invert the plane. The altitude loss is about 650(800)m and the speed when returning at horizontal would be about 350(400)km/h

15.To perform slow roll, try them from 2600RPM, speed 320km/h and start them as the usual process.

16.To perform quick turn, try them from 2600(2900)RPM, Manifold pressure (+)100mm Hg(+250), speed 380(400)km/h and start them as the usual process. left turn will force the nose down easier because of torque effect, right turn will force the nose up easier. When you keep turning, the speed defers by its tilt, horsepower, plane`s load, etc. The turn radius and time is as follows:
800~700 Altitude
360 degree 180degree Turn
Right Left Right Left Turn heading
20.00sec 17.05sec 8.55sec 9.15sec Turn time
260m 260m 260m 270m Turn radius(about)
2900RPM, Manifold pressure (+)250mmHg Notes

17.To perform quick ascend, you need a slow 3G to do this. If pull up were too rough, it will drastically decrease your gaining speed and lose your gaining altitude so be careful. So when you keep 2900RPM and maximum intake pressure when climbing, you can gain almost same climb as the descending altitude.

18.When diving in deep angle, do not over-use the elevator tab(trim?). The push for stick will be related against the speed and inversed getting heavier against the dive angle but, unless it is required you have to keep the tab within 5 degree down. When performing a dive, you have to take enough altitude and increase your speed slowly so you can learn enough, and then dive deeper within the limit speed. Here we have a sample for the deep dive.
Start roll and dive with angle of 60degree, tab down 5 degree, Altitude 5000m, 2900RPM, Manifold pressure(-)100mmHg, Speed 350km/h
-2.While diving
Open the Manifold pressure up to (+)250mmHg
-3.Pulling back to horizon
Altitude 1300m, 2900RPM, Manifold pressure(+)250mmHg, Speed 750km/h

-1.Do not overrev the props unless when malfunctioning.
-2.Close the gas valve controller for about half
-3.Elevator tab are required to check severely before piloting.
-4.If the plane starts to vibrate when diving, full close the gas valve control and slowly pull up.

19.Vertical dive have to be done with the process of dive and these cautions. The speed increase when vertical diving is very fast and altitude loss required for pull-up is big so it need with caution.
Here we have a sample for vertical dive.
Altitude 5000m, 2900RPM, Manifold pressure (-)100mmHg, Speed 300km/h
-2.While diving
Open the Manifold pressure up to (+)250mmHg
-3.Pulling back to horizon
Altitude 1300m, 2900RPM, Manifold pressure(+)250mmHg, Speed 750km/h

This is about as much as I have. It's 53 pages after all and I cant force anyone to do this for free as a friends request.

Hope that is interesting and helps, and as I said, it was not done by a fluent english speaker so can be hard to understand.
« Last Edit: December 13, 2014, 07:09:30 am by Hiromachi » Logge ...

Ron, 26.12.2015

A translation of a Ki 84 test:
"A function and the handling of Ki-84 fighter. 3rd January 1944 (Showa 19).

Chapter1 - Main Specification

Section 1 - Main Specification
This plane is All metal low wing single seat monoplane, here we have a spec:
Wingspan - 11.238m
Length - 9.870m
Height(horizontal) - 3.385m
Wing area - 21 m2
Dihedral angle - 6.0
Aspect ratio - 6.08
Flap area - 2.436 m2
Aileron area - 1.376 m2
Horizontal stabilizer area - 3.079 m2
Elevator area - 1.074 m2
Vertical stabilizer area - 0.761 m1
Rudder area - 0.889 m2
Empty load - 2712 kg
Full load - 3763.5 kg
Wing loading - 178kg/m2
Powerloading - about 2.5kg/hp
Fuel - Aviation 92 gasoline ( 697 l )
Methanol and Water - 130 l
Engine oil - 50l (Full capacity 80l)
Armament - 20mm x2, 13mm x2

Name - Ha-45
Type - Air cooled twin row radial 18cyl
Output - 1500hp/8500m

Name - "Pe-32" electical constant speed propeller
Diameter - 3.10m

Max speed - 624km/h
Climb time - 12min 16sec to reach 8000m
Service ceiling - 11000m
Landing speed - 140km/h

Chapter 2 - Construction Functioning

Section 1 - Aircraft

@@ Subsection1 - Aerodynamic characteristics
The wing is capable of sustaining speeds of about 700km/h. The wing`s square shape is considered for stall and stability, contraction ratio 1.81 straight downhill tapered. To improve stall characteristic, as tip border to prevent early stall of wingtip we added 2 degree of twist down.

Vertical and Horizontal stabilizers both have thickest point at 40% chord length. The stabilizer area and position of balance is decided by consideration to the stability at high altitude and stability when controlling the flap.
The movement of horizontal stabilizer is mouted above the fuselage and angled + 3 degrees to improve the angle of attack against the draft from main wing.

The maximum width is decided from the engine`s diameter 1.180m, it is tapered smoothly to the tail.
Overall the shape of fuselage is shaped with simple curve, unlike straight shape so it can reduce drag.

The chord length of ailron`s back is reaching 20% of main wing, its balance is 25%. controllable angle is 15degrees down, 20 degrees up.
Elevator is decided considering to the effectiveness at landing and takeoff, controllable angle is 30degrees for pull, 20 degrees for push, also have trim.
Rudder is decided considering to the effectiveness at takeoff, controllable angle is 30degrees for left and right.

To improve the landing and takeoff performance of this plane which have high wingload, this plane is designed to use butterfly flap effectively enough to improve lift. The control angle of flap is 15degrees at takeoff, 30degrees at landing, Here we have the estimated maximum lift coefficiency:

Flap angle 0 degree: Max lift coefficient 1.46

Flap angle 15 degree: Max lift coefficient 1.70

Flap angle 30 degree: Max lift coefficient 1.92

Section 2 - Structure

Wing is all metal one side held single frame monocoque constructed, it have single wing, and its wingtip and cranial border tank can be dismounted.
For the center part of wing, it have 217L fuel tank, left and right wing have 173L fuel tank each, also split by 20mm cannons its outer cranial border it have 67L fuel tank.
Center wing cranial border have landing gear inside.
Ailerons are constructed with metal frame and fabric outer, it is perfectly balanced by counterweight placed on cranial border, and it have a correction rudder.
Flaps are fully metal constructed and it actuates by hydraulic, only used at takeoff and landing.

2.Tail stabilizers
Both the vertical and horizontal stabilizer are all metal construction.
Elevators are constructed with metal frame and fabric outer, and it have a metal constructed correction rudder. And it is perfectly balanced by counterweight placed on cranial border.
Rudder are also constructed with metal frame and fabric outer. And it is balanced by counterweight placed on lower cranial border. and it have a correction rudder on its caudal border.

3. Fuselage
It is metal constructed half monocoque construction, it can be separated into front and back part at 9th semicircle from the back of the seat.
Frontal fuselage is connected to wings by its lower mount base, and it have a pipeframe weld engine mount on front.
On the back of the cockpit the 12mm steel board is mounted to defend from bullet, and canopy have a emergency opening device.
It have a meintenance hatch on the bacl left side of the fuselage.

4. Landing gear
Main landing gear is completely retracted inside the wing`s cranial border by hydraulic, also it is fixed by hook at both the completely retracted and extended position.
Gear tower have a air/hydraulic absorber, it have a wheel and 650 x 170mm high pressure tyre. Brake is hydraulic.
Tail wheel have air/hydraulic absober tower, wheel and 200 x 75mm tyre, it can be both in fixed ...

Ron, 23.12.2015

Initial climb of the Ki 116 Hayate was 1,000m/min.= 3280fpm.

Ron, 10.12.2015

30.3 and 4.45 lb are the W/L and P/L for the 1560 hp Ha-112-II powered Zero A6M8 for comprison. But the Hayate Ki 116 is almost 30 mph faster for the same or better aerobatics with it's combat flaps!

Ron, 10.12.2015

The W/L of the Ki 116 was 30.1 lb/s.f., 4 lb lighter than the Ki 84!! 35.8 for the Ki 100!!
Acceleration however was off a touch. P/L was almost 4.7 lb/hp, 0.7 heavier. 5.1 for the Ki 100!!

So it should easily narrow the gap with the Ki 100 in a dogfoght, namely in turn and climb performance.

Ron, 22.11.2015

The unavailability of engines forced the decision to use the reliable Ha-112-II with a 3 blade prop (same as Ki 100). The prototype flew before the war ended. It's weight was 1,000 lbs lighter, improving agility; but speed dipped to 385 mph @ 19,000', 342 @ 12,000'. Still faster than the Ki 100-Ib by 25 mph with the same power!
Loaded weight was just over 7,000 lbs.
The end of the nose was more blunt like the Ki 100. Tail area was larger than the original.

I wonder how it would do in a mock dogfight with the Ki 100 or anything else.

TORBJÖRN KAMPE, 18.10.2015

this aircraft has lot of good maneuverability.
better than the Spitfire. and snabare and more armed.
a mix of BF-109 and FW-190.
I think lot of good for this aircraft.
for its flight characteristics.
it is betere a zero zen.

Ron, 04.03.2015

The Ki84's test dive was interrupted at 497 mph due to the pilot's oxygen malfunction. It probably could do much better since the Ki 44 (with slower level speed by about 15 mph) could dive to 528 mph! I wouldn't be shocked if the Frank could outdive the Tojo by the same margin of 15 mph or so in the 540s I would guess.
Perhaps not, depending on dive stability and vibration etc... since the Ki 44 engine was more reliable. Unless someone has better data, we can only speculate. Maybe my former posts are in question where I compared the Frank's 497mmph dive with that of the Ki 100 at 528 mph limit (matching the Ki 44). The limit of the Frank is still a mytery.

Percy, 06.12.2014

The Japanese produced some fine aircraft during WW2, A Royal navy official had said that if the British navy had Japanese naval air craft on its aircraft carriers both the Italian and German navies would have ceased to exist .

Ron, 25.09.2014

I think the 5g turn limitation of the Ki 84 hurt it in comparison with the much better Ki 100 in horizontal combat and inferior zoom-climb but better initial dive in the vertical.
The Hayate had sluggish controls vs the Kawasaki Goshiki-sen as well.
The type 4's more powerful 18 cylinder engine faded faster above 21,000' than the modest 14 cylinder motor of the Type 5 fighter.

Ron, 22.05.2014

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.

1-20 21-40 41-60

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