F4F Wildcat versus P-40E Tomahawk

[renrich]

The weight given for the model 52a is full load-6035 lbs. It actually shows a layout of the cockpit.

[HoHun]

Hi Renrich,

>The weight given for the model 52a is full load-6035 lbs.

Thanks, that seems to fit the Navy test aircraft.

>It actually shows a layout of the cockpit.

Is the boot pressure indicator visible? It would be interesting to see if it has the coloured sector from 0 to +250 mm Hg, or if it actually goes to +300 mm Hg. (If the layout is schematic only, I'm afraid we're out of luck.)

Regards,

Henning (HoHun)

[Micdrow]

Statistics on Japanese zero's from the book zero by Robert C Mikesh published by Warbird History

[ponsford]

Interesting Micdrow. For Mikesh’s sources see:

Source 1: Informational Intelligence Summary No 85.
Source 2: Performance Flight Test on a Japanese Hamp, AAF No. EB-201.

[Micdrow]

Originally Posted by ponsford

Interesting Micdrow. For Mikesh’s sources see:

Source 1: Informational Intelligence Summary No 85.
Source 2: Performance Flight Test on a Japanese Hamp, AAF No. EB-201.

Very interesting ponsford, I noticed that the documents that he listed as sources dont match the actual documents for max speeds but they do match rate of climb.

Very interesting and many thanks.

[HoHun]

Hi Ponsford,

>Source 2: Performance Flight Test on a Japanese Hamp, AAF No. EB-201.

Highly interesting!

The settings used for this test were +150 mm Hg, 2400 rpm ... TAIC data credits the engine with +200 mm Hg, 2700 rpm for mil and +300 rpm, 2750 rpm for WEP.

Comparing sea level powers:

WEP 1115 hp/2750 rpm/41.7" SL
MIL 995 hp/2700 rpm/37.8" SL

If we assume that power is linear to rpm and boost pressure, this means that the A6M3 in the test got only about 837 HP at sea level under the test conditions.

If the engine actually made these +300 mm Hg, 2750 rpm at WEP, that would yield a sea level top speed of roughly 308 mph or 496 km/h (assuming that top speed increases to the third power of power) instead of the 280 mph achieved in the test. That seems to be quite a bit faster than most Zero data I have seen ...

In fact, if I simply use the A6M2 drag and wing data in combination with the weight data for the heavier A6M3 in combination with the TAIC engine data for WEP, that gives me a top speed of 486 km/h @ sea level, which is faster than most A6M data I've seen, too - but still a conservative guess as the A6M3 has a smaller wing and thus less drag in high-speed flight.

Accordingly, the test performance of the A6M3 and my calculations seem to have at least a semi-decent fit - I guess that for assessing A6M performance, it comes down to the question: "Which ratings did the Sakae engines really use"?

I think we have a good idea of the boost pressures used (big thanks to Micdrow for the excerpt from Mikesh's instruments book - very useful! , but the maximum rpm are still open ... maybe there are some markings on the rev counters, too?

Regards,

Henning (HoHun)

[HoHun]

Hi again,

>I think we have a good idea of the boost pressures used (big thanks to Micdrow for the excerpt from Mikesh's instruments book - very useful! , but the maximum rpm are still open ... maybe there are some markings on the rev counters, too?

Reading the rest of the reports on Mike's site WWII Aircraft Performance I notice that the A6M2 Material Command memorandum assigns the following values to the A6M2:

Speed at sea level: 277 mph @ 2600 rpm, +120 mm Hg

This is less than the +150 mm Hg ascribed to the engine by the TAIC report for the MIL setting - but it turns 100 rpm faster than the TAIC MIL setting, too. I'm beginning to get confused!

On the other hand, the above speed at sea level is not compressiblity-corrected.

Regards,

Henning (HoHun)

[Micdrow]

Your welcome Henning, though like you I am confused on a few things also. 5years ago I researched this aircraft for 2 years and I never did find complete answers and ended up giving up though in the last few years more info has surfaced.