State-of-the-art Japanese fighters with western engines

[spicmart]

What about Kawanishi Ki-61/ Nakajima Ki-84 hypothetically equipped with Griffon/Jumo 213/DB 603 engines?
Would they have been the equal of any ETO top tier fighter designs?

 

[tomo pauk]

Probably a bit slower than the Fw 190D-9, but with the tighter turns possible.
With 2-stage supercharged engine versions, probably as fast as Merlin Mustang, or at least as the P-47D.

 

[spicmart]

Probably a bit slower than the Fw 190D-9, but with the tighter turns possible.
With 2-stage supercharged engine versions, probably as fast as Merlin Mustang, or at least as the P-47D.

Both Ki-61 and Ki-84 have greater wet area than the Dora. The Ki-61 had the same wing profile as that of the Me 109, not exactly a low drag airfoil.
Don't know about the Ki-84's. Weight of both would be about comparable to a Griffon Spitfire
Having bigger wings (20 and 21 m^2 respectively) they should perform a tad better than the Dora at altitude with different Jumo 213 versions.. With a Griffon they should be as good as the Spitfire XIV, maybe a bit better down low and a bit less up high as the Spit has 22.5 m^2 (20 Series have 23.5 m^2) wings.

If you gave them annular/drum radiators Dora-style would they be more than or just as aerodynamic as the XIV?
When the Ki-61 kept its underslung radiator it would be very similar to the Italian Series 5 fighters.
A Mustang style rad would give it a plus thrust-wise and would compensate for the wing profile.

The Ki-100 was said to have been comparable dive characteristics to the Mustang which I highly doubt. It's aerodynamics and weight were just not up to par.

 

[SaparotRob]

Both Ki-61 and Ki-84 have greater wet area than the Dora. The Ki-61 had the same wing profile as that of the Me 109, not exactly a low drag airfoil.
Don't know about the Ki-84's. Weight of both would be about comparable to a Griffon Spitfire
Having bigger wings (20 and 21 m^2 respectively) they should perform a tad better than the Dora at altitude with different Jumo 213 versions.. With a Griffon they should be as good as the Spitfire XIV, maybe a bit better down low and a bit less up high as the Spit has 22.5 m^2 (20 Series have 23.5 m^2) wings.

If you gave them annular/drum radiators Dora-style would they be more than or just as aerodynamic as the XIV?
When the Ki-61 kept its underslung radiator it would be very similar to the Italian Series 5 fighters.
A Mustang style rad would give it a plus thrust-wise and would compensate for the wing profile.

The Ki-100 was said to have been comparable dive characteristics to the Mustang which I highly doubt. It's aerodynamics and weight were just not up to par.

 

[GregP]

The Ki-100 is widely held to be the best, or at least one of the two best fighters the Japanese fielded. Not too sure its aerodynamiccs are not up to it if given an Allied liquid-cooled engine.

After all, there would be no wide radial faired into the narrow fuselage. But, you might be correct.

Would be a good one to look into if someone had the time and inclination to do so. But, we'd have to pick an engine. I'd say late-model Merlin with 5-blade Rotol p;ropeller.

 

[GregP]

OK. Let's assume a Ki-61 instead of a Ki-100 and let's use a 2-stagemodel Merlin, say a <erlin 61.

At medium altitude, the Kawaswaki Ha-40 engine made 1,050 hp, 360 mph, and climbed 2990 fpm.

The Merlin 61 makes 1,565 hp at the same altitude, translating into 411 mph and 5,400 fpm rate of climb, all assuming no chage in drag. If we add 5% extra drag, we're still over 400 mph and climbing at 5,000 fpm, all of which make it VERY competitive with late-war allied planes that were actually in the war.

 

[Shortround6]

At medium altitude, the Kawaswaki Ha-40 engine made 1,050 hp, 360 mph, and climbed 2990 fpm.

The Merlin 61 makes 1,565 hp at the same altitude, translating into 411 mph and 5,400 fpm rate of climb, all assuming no chage in drag. If we add 5% extra drag, we're still over 400 mph and climbing at 5,000 fpm, all of which make it VERY competitive with late-war allied planes that were actually in the war.

What is the installed weight of the Ha-40 powerplant?
Engine, radiator, coolant and propeller?
Same for Merlin 61 (or equivalent)

The Ki-61 S (super) will be a lot better But I think that some of extra climb disappears.

From AHT for the P-51B & C

engine section..................274
engine (W/acc)...............1670
engine controls...................30
propeller.............................483
starting...................................25
cooling................................663
lubrication..........................101*
Fuel system.........................----

The bold are the major weight changes, the italics are going to be very small changes and could be in favor of the Japanese. The oil system can go either way bit we are arguing over around 40lbs? (based on weight of lub system in P-40)
Trying to figure out the fuel system with different sizes, numbers and fuel tank materials is kind of pointless and I will simply assume the fuel system stays the same.
P-51B gained about 550lbs over the P-51A (both set up for 4 .50s but not installed) in empty weight.
Weights for Ha-40, propeller and cooling system (or German equivalents appreciated).

 

[GregP]

Dry weight of the Ha-40 is 1,320 lbs. Dry weight of the Merlin 61 is 1,640 lbs. So, about a 320 pound difference. When you're talking a 7,200 lb airplane, that doesn't make much difference. Less than 5% difference in weight.

 

[SaparotRob]

So an extra carry on bag is okay?

 

[ThomasP]

Only if it is a maximum of 22 in x 14 in x 9 in (56 cm x 36 cm x 23 cm), including handles and wheels.

 

[GregP]

It has to fit in your fight attendant's back seat when you leave tghe airport.