Ki-84 changes

[1K3]

Made flight model changes to the Ki-84. Mainly, a lowering of climb rate at military power and the addition of a short amount of overboost capability.

does it still have the "1943 test trial" speeds?

[Widewing]

Ok, here’s what I got testing the Ki-84 this morning:

Speed on deck, no WEP: 327 mph
Speed on deck with WEP: 348 mph
Speed at 22,500 ft without WEP: 382 mph
Speed at 22,500 ft with WEP: 388 mph
Climb: 25% gas; from a standing start on runway to 5,000 ft: 87 seconds. For comparison, I did the same test with an La-7 with 50% gas in its tanks (about equal duration to Ki84 with 25% gas). The La-7 took 86 seconds to reach 5,000 feet. A virtual dead heat.

WEP duration: About 90 seconds
Cool down to normal temperature: About 30 seconds

So, you have a WEP duty cycle of 90 seconds on, 30 seconds off, 90 seconds on and so on.

Elevators seem lighter than before patch, but that may just be my own perception.

Conclusions: The Ki-84 is even deadlier than before. It can run away from any of the other turn fighters with ease. Especially when we factor in acceleration.

Yup, the revised Ki-84 accelerates much faster than the previous edition.

I did my standard acceleration test: level at 200 feet, power adjusted to speed is stable at 200 mph. Go to full power and engage WEP, record time required to reach 300 mph.

You may remember that the previous Ki-84 accelerated dead even with the Spitfire Mk.V. Well, that's changed dramatically.

Times from 200 mph to 300 mph:

La-7: 28 seconds
Ki-84: 29 seconds
Spit V: 51 seconds

With these numbers, the Ki-84 just moved higher up the uber scale.

My regards,

Widewing

[Kaz]

Widewing what did you use to measure the speeds? I used the E6B and couldn't get above 342mph with overboost, 324mph full military. Wonder if alt is a factor here, I went as low as possible (around 20ft ASL)

[Widewing]

Originally posted by Kaz
Widewing what did you use to measure the speeds? I used the E6B and couldn't get above 342mph with overboost, 324mph full military. Wonder if alt is a factor here, I went as low as possible (around 20ft ASL)

How much fuel were you carrying? Hammer's testing showed that fuel load has a significant effect on speed. I was flying with 25%, zero burn rate.

It seems that the limiting factor here is WEP duration. Try this: Climb to 2k, dive down to 200 feet (in MIL power). Let your speed degrade down to 360 mph. Engage WEP. You will see that the airplane will sustain 347/348 mph until it runs out of WEP. When accelerating to max speed, you will run out of WEP before you can get there. I can't get better than 344 this way. In terms of actual usage in the MA, I can't think of many instances where I would not be diving to the deck in pursuit of an enemy.

So, let's amend max speed on the deck to say that depending upon various factors (fuel load, ammo load, etc), it may vary between 342 and 348 mph.

Using acceleration from 200 mph, I saw 324 mph at MIL power, 344 mph when the WEP quit. Decelerating from 360 mph, I saw 347/348 with WEP and down to 326 sustained in MIL (it takes miles to lose just 1 mph) for 3 minutes. Longer runs may result in additional speed loss. I only tested for 3 minutes.

Either way, the Ki-84 is at least 20 mph faster on the deck than before, and that is significant.

My regards,

Widewing

[Mitsu]

343mph in my test. (Sea Level @ 20ft)
Anyway, the updated Ki-84 holds much better Es on the deck.
BTW thanks for reporting accel test, Widewing.

[Kaz]

That explains it then I was using 100% fuel. Thanks for the explanation.

[Badboy]

Originally posted by Kaz
That explains it then I was using 100% fuel. Thanks for the explanation.

The speed you quoted is correct, within 1mph for a fuel load of 25%. Others have posted values 1mph faster than you, and which of the two readings you get depends on how you carry out the test, the true value is somewhere in-between the two.

Widwing's value is higher than the correct value. You can confirm this with a high degree of repeatability and consistency, if you re-fly the tests. But don’t forget that acceleration/deceleration is very slow close to the top speed, and the wep duration is only short, so don’t start too far away from the anticipated value or you won’t have time to get there before the wep runs out, as Widwing pointed out.

Also, the fuel load only makes a small difference to the top speed. With a full tank, you would only expect the speed to drop slightly, perhaps 3mph or less depending on the fuel quantities involved. You can also confirm that with good consistency by similar tests.

Hope that helps…

Badboy

[Karnak]

I get 343mph at 20ft and 344mph at 200ft with 25% fuel.

[Badboy]

I can confirm that Karnak and Mitsu's values are correct.

Badboy

[Widewing]

Originally posted by Karnak
I get 343mph at 20ft and 344mph at 200ft with 25% fuel.

I get the same numbers accelerating to speed. A bit higher coming down over 3 minutes. But if you wait long enough, it does drop down to 344 at 200 feet.

My regards,

Widewing

[TequilaChaser]

my figures were near same, posted in the

Patch 5 thread in General Discussion

I came up with  1min 30 to 31 secs WEP with a 46 to 47 sec cool down period timed 10 out 10 times.....

my top speeds were based on E6B and after attaining top military speed I tested wep with top speed of WEP at time it shut off.....

[Karnak]

Widewing,

I have always used the deceleration method of speed testing ever since I did speed tests in AH.

To get the 343mph and 344mph numbers what I did is wait until the speed drops to 350mph and then turn on WEP.  Once the WEP expired I look at the speed.

[Widewing]

Originally posted by Karnak
Widewing,

I have always used the deceleration method of speed testing ever since I did speed tests in AH.

To get the 343mph and 344mph numbers what I did is wait until the speed drops to 350mph and then turn on WEP.  Once the WEP expired I look at the speed.

You can still reach 344 mph, just don't engage WEP until you stabilize at 323 mph. However, not long after, you run out of WEP.

My regards,

Widewing

[TequilaChaser]

Originally posted by Karnak

I have always used the deceleration method of speed testing ever since I did speed tests in AH.

Karnak,
I use the deceleration method for Military power, I dive for excess speed then let it stabilize, then once it stops dropping I wait 10 minutes, then I turn on WEP and note speed as soon as wep runs out.

for timing WEP operational use and cool down time, I do it on an average of 10. I time its use and cool down 10 times then total them and divide by 10 to get my average, speeds I usually just take avarage of 3, but most times all 3 are indentical....

most people will not be diving and then turning WEP on, they will be wepping thru out the whole fight or chase from the start, this is my reason for recording wep speed the way I do...not that it really matters.......

but: this Ki-84 goes a good ways before it starts to decelerate!

[Karnak]

TequilaChaser,

Actually I test it the way I do for the same reason.  We just reached oposite conclusions.

I test for terms of diving to the deck and pusuing, or running.  In either case the aircraft will almost certainly be well over it's sustainable speed, so I am more interested in watching it's deceleration to it's sustained WEP and MIL speeds.  Very rarely do I find myself on the deck using WEP to try to accelerate to top deck speed.  I cannot, in fact, think of an occasion when I've ever done so.