N1K2 Flight Test, Part I (Climb)

[Vermillion]

N1K2 Flight Test, Part I (Climb)

Test Protocol
I loaded the N1K2-J with no external stores, and full fuel and ammunition. This is to correspond to the "historical" data that I have for it, with a testing weight of approximately 9,500lbs. This is also the approximate "loaded weight" listed in most tabel top reference books that I own.

After takeoff, aircraft was trimmed at level flight at 800 ft. and a auto-speed climb rate was set for 175 IAS. (note: aircraft can not be set to autospeed climb below 800 ft without it going into a terminal dive,even if speed is greater than 175 IAS).

Full Military Power was applied and autospeed climb initiated. Rate of Climb Data readings were taken every 1,000 ft., until aircraft reached its service ceiling. Data was input into Excel for graphing.

Test repeated at War Emergency Power (WEP).

Results
   

AH Test results are compared to the data provided on the performance graphs from the AW2 boxed set, reportedly from NASM historic flight tests.

Conclusions
If the historic data from the AW2 charts is assumed to be correct (which is the best data I know that is commonly available, other submissions highly appreciated), the Aces High N1K2 is suffering from a lack of climbing ability. If you compare the "Expected" value to the "Tested-WEP" values you see that it is producing only about 75%-80% of its climbrate thru out the testing range.  

Even in the upper altitude ranges where it seems that the two results tend to compare more closely, it should be noted that the fuel modifier in AH is reducing the ammount of error. In real world testing the aircraft would still have much more fuel (ie heavier, and lower climbrates) at those altitudes than the AH aircraft, since it would have only burned 40% as much fuel.  Therefore, in such tests the "Tested" climbrates at the upper altitudes should actually exceed the historical values, which it clearly does not.

It should also be noted that the reference book Max Ceiling for the N1K2-J is approximatly 35,000 ft. In testing, using both MIL and WEP power the AH aircraft did not reach the reference max ceiling. Under MIL power the aircraft at 32,000 ft, reached a ROC of less than 200 fpm (definition of max ceiling I believe). Under WEP power, it reached the 200fpm value at 33,000 ft.

Further Testing (Speed vs Altitude, Max Turn vs Altitude) will hopefully be completed and the results presented here before the end of the weekend.  And if Pyro can provide Clmax, and Cdo, I can do the tests for Acceleration vs Speed vs Altitude.

Comments, opinons, or insults, welcomed.

PS: Further testing will depend on how much free time the girlfriend absorbs, since she is visiting this weekend  


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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,



[This message has been edited by Vermillion (edited 11-04-1999).]

[funked]

Can you plot that without the curve-fit?  Just connect the dots.

[Vermillion]

 

Here you go Funked. It doesn't make much difference as you can see. Most of the spiking on the tested lines can be attributed to the fact that I am trying to read an analog ROC gauge, and estimate anything that isn't a whole, half, or quarter (1,1.25,1.5,1.75,2) vaule on the gauge.

If Pyro or HT would be so kind to provide me an FE with digital gauges, I'm sure my graphs will be much prettier  

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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,

[funked]

Thx Dude!

Better than digital gauges, I would like "telemetry" - a feature allowing me to dump to an ascii file 6-axis position and velocity plus stick/rudder/throttle data.

[Vermillion]

Dohhhhhh !!!!!      

I just spent two hours doing the next step of the testing, the maximum IAS vs Altitude, test.

Got two thirds of it finished when I realized that there were 8 ticks per 100 mph, instead of the 10 ticks I thought it was.  Grrrrr


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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,

[gatt]

Vermillion (the AH -Hoof-  ),

great work!! If only we could have times to various altitudes ...  

Regards,
Gatt

[Vermillion]

Gatt, climb to 19,500 was somewhere in the neighborhood of 7 mins 45 secs (approximately, due to lack of an accurate reference number, I didn't make sure I was hyper accurate on my time test. I was more interested in the Rate of Climb, ie vertical velocity, for which I had better data to compare).
The biggest problem is that there isn't really much to compare it too. Unfortunately, good data for Japanese aircraft is extremely hard to find, especially the late war stuff. US, German, and English aircraft data is pretty good in most of the more common references. The Japanese and the Russian information isn't anywhere near as good. Pick up your 3 favorite references and look up the George, I bet there is quite a difference in the "Specifications & Performance" section.

Probably the best Japanese aircraft book I have seen, "The Japanese Aircraft of the Pacific War", by Francillon, lists the George as having a climb rate of 7 mins 22 seconds too 19,515 ft. But he also lists it as a combat weight of 8,500 lbs or so, whereas many others list the loaded weight as in the 9,500 lb range.

Thats why I would love to get my hands on the original reports that the Air Force and Navy did on the George right after the war. Until I see those, I will be skeptical of any data that I do see.

Pyro I would gladly order the documents myself if you could just provide me with the document titles and reference #'s. Purty Please   ?? It is my favorite plane after all.


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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,