Ki-84 exaust stacks?

[humble]

I'm certainly not up to speed with those of you who are WW2 aircraft techies...

In doing a bit of research on the Ki-84 I found this type of comment in numerous places on the web...

A second pre-production batch of 42 Ki-84s was started in April of 1944. These were built between March and June of 1944. These were built in parallel with the first production aircraft, which began to roll off the production lines in April of 1944. Both types were fitted with individual exhaust stacks, which provided some thrust augmentation, and could increase the maximum speed by some 9-10 mph.

Since the original prototype tests were documented at 388...

A few service trials machines were handed over to the Tachikawa Army Air Arsenal. JAAF pilots commented favorably on the machine, although its maximum speed was below the requirement. The aircraft had a maximum speed was 388 mph, could climb to 16,405 feet in 6 minutes 26 seconds, and had a service ceiling of 40,680. This made the Ki-84 the best-performing Japanese fighter aircraft then available for immediate production.

Wouldnt the original production model (I believe thats what we have modeled in AH2) have a top speed of 397+MPH?


somehow this doesnt sound like the bird we have....

The FRANK later appeared in the battle for Okinawa, serving with the 101st, 102nd, and 103rd Hiko Sentais. Two new Sentais, the 111th and the 200th were activated with Hayates. The Hayates were used for long-range penetration missions, fighter sweeps, strafing, interception and dive-bombing missions with considerable success. The Ki-84 proved faster than the P-51D Mustang and the P-47D Thunderbolt at all but the highest altitudes. At medium altitudes, the FRANK was so fast that it was essentially immune from interception. The climb rate was exceptionally good, 16,400 feet being attained in 5 minutes 54 seconds, which was superior to that of any opposing Allied fighters

Was hoping for the frank....










































and got the beans instead:lol

[Overlag]

do we really need another LA7? (speed)

[streetstang]

lol humble. Good one.

[humble]

Originally posted by Overlag
do we really need another LA7? (speed)

No....

Truthfully I really dont care about any one particular plane. However, as an international community many want to fly planes associated with a particular side. Since the Ki-84 is constantly referred to as the "flagship" fighter for Japan in WW2 I can see a legitimate need for a representative model. I do feel that using preproduction test data and the most conservative power settings is a bit harsh. However, I'm more confused by the FM for the plane. I cant find any reference to such mediocre handling and poor structural integrity anywhere. As I've flown it a bit I've grown to like it a bit...but I gravitate to the mediocre planes anyway:D

[Karnak]

Originally posted by Overlag
do we really need another LA7? (speed)

No one was asking for an La-7 speed aircraft and no one (other than ex-AW players) was expecting one.

We simply expected a good fighter instead of the crappy fighter we got.

[1K3]

I can't dig it. I was also expecting that Ki-84 will raise the bar (way higher) on the Japanese Navy/Army planeset. Like most people said 24 hrs ago, the current '84 we have here is like modelling a P-51D with and Allison engine (!).

[Wotan]

The AH Ki-84 doesn't have the the modified exhaust stacks.

The 388mph was derived from a prototype powered by Homare 45 Model 11.

Re:AIREVIEW's:"General View of the Japaese Aircraft In The Pacific War"/Vol.2-English-edition/Pg.51(Subj:MYRT):

"The jet unit, which was attached to almost all of the Japanese military aircraft in the latter stage of the war served to increase the speed by about 15 knots, tantamount to increasing the engine power by 10 to 15 per cent."(sic)

See Mitsu's graph:



The HA45 SP (Ho-45/11) represents the Ki-84 as modelled in AH.

It was the Ho-45/21 that:

The Ki-84 proved faster than the P-51D Mustang and the P-47D Thunderbolt at all but the highest altitudes. At medium altitudes, the FRANK was so fast that it was essentially immune from interception. The climb rate was exceptionally good, 16,400 feet being attained in 5 minutes 54 seconds, which was superior to that of any opposing Allied fighters

It ran at higher mmHg, higher rpm and HP. The test the US did at Wright Patterson was of a Ki-84 with Ho-45/21. AFAIK no one has found any documentation of those tests.  They used 100 octane fuel. I have read by can not confirm that this was done to reach the same power as a Ki-84 using 92 octane + water methanol.

Next best source might be a Type 4 pilot. W.O. Yukio Nakamura flew the Type 4 fighter in Japan and then in combat in the Philippines. He was captured by the Americans and interrogated (he was deemed "fairly reliable") and gave detailed information on the Type 4 fighter. According to Nakamura the aircraft's max speed was 700 kph true airspeed. That comes out to about 434 mph.

The AH Ki-84 has a max boost of 250mmHg. However, take off power for the Ho-45/11 is stated as 400mmHg @ 2900 rpm. This means that the Ki-84 as modelled in AH could run at a higher boost then 250mmHg. I don't know if these means more power because its the 400mmHg power setting that prodeced 1800hp @ SL. However if the Ki-84 version as modelled in AH could exceed 250mmHg the questions becomes how much higher, how long and how much of a speed gain.

The 250mHg boost maybe the max allowable boost for the version of Ki-84 as modelled in AH. See Pyro's reply to the 'wep' question in the other thread.

The only game I know that models the Ki-84 with a Ho-45/21 with water methanol is FB/AEP. IIRC the warbirds Ki-84 is modelled on the same data as AH2s.

[Kaz]

That graph verifies my test at 20.5k of 382mph but if this is the case shouldn't the deck speed be about 310-311mph (if I'm reading the graph correctly) instead of the 324mph modelled in game?

Just asking.

I'll test again at 23000ft, see if I get the same results.