USA: Mitsubishi A6M3 Zero of the Military Aviation Museum takes off

[dewoitine]

Sorry, in French!

USA: le Mitsubishi A6M3 Zero du Military Aviation Museum prend son envol – L’Echarpe Blanche

www.lecharpeblanche.fr

On May 5, at Paine Field, Everett, Washington, USA, Mike Spalding conducted the new first post-reconstruction flight of the Mitsubishi A6M3 Model 32 Zero . Rebuilt by Legend Flyers and registered NX9940 , the aircraft belongs to the American collector Gerald Yagen and his Military Aviation Museum based in Virginia Beach, USA. This former Imperial Japanese Navy fighter is probably the first model 32 to fly since 1945.

 

[TARPSBird]

An old Navy shipmate of mine is a docent at the Military Aviation Museum, where this Zero is headed. He has invited me to spend a day at the museum with him and now I'll wait until the Zero gets there.

 

[stansdds]

Yes! A wonderful restoration to airworthy condition. It was originally to be restored using a Nakajima Sakae-21 engine, but cost and availability forced the restoration to use a P&W R-1830. The propeller is actually a DC-3 prop and the prop spinner is from a Lockheed Super Constellation spinner.

 

[Allen]

 

[dewoitine]

Amazing flight after 80 years!

 

[Ivan]

Did the A6M3 Model 32 have a rudder trim tab configured like the A6M2 (Ground Adjustable) or like the A6M5 (Flight Adjustable)?
This one ground adjustable and I thought that had gone away with the A6M2.

 

[Ivan]

In watching the videos, I can tell you that the narrator in the first video really doesn't know anything about the A6M3 he is trying to describe.
Many of the details he notes are outright wrong.

- Ivan.

 

[sixstrings5859]

Amazing ! Didn't know about this. Just a lovely warbird !

 

[Ivan]

About 10-20 years ago, there were about a dozen new construuction A6M airframes built in Russia. These were new construction and not restored wrecks. As such, there were probably a few changes made to suite the fact that these were no longer combat aircraft and were most likely going into the airshow circuit and would be powered by P&W R-1830s instead of the original 1700 CID Sakae engine. One of the observations that can be made with some of the modern aircraft is that the "No-Step" area over the Flap Wells is no longer being observed. The original aircraft had very thin sheet metal over these areas and an outline denoting a "No-Step" area. The Pilot and Ground Crew accessed the cockpit by using retractable pegs intended to support their weight. This wasn't easy but was necessary because of the light construction. My belief is that the new construction airframes did not reproduce the cockpit adjustable Rudder Trim in order to simplify construction. In other aircraft such as the Chino A6M5, the fuel capacities are not original and the fuselage fuel tank is not installed. I suspect this is the most likely situation here as well.

 

[Bomber_12th]

About 10-20 years ago, there were about a dozen new construuction A6M airframes built in Russia. These were new construction and not restored wrecks. As such, there were probably a few changes made to suite the fact that these were no longer combat aircraft and were most likely going into the airshow circuit and would be powered by P&W R-1830s instead of the original 1700 CID Sakae engine. One of the observations that can be made with some of the modern aircraft is that the "No-Step" area over the Flap Wells is no longer being observed. The original aircraft had very thin sheet metal over these areas and an outline denoting a "No-Step" area. The Pilot and Ground Crew accessed the cockpit by using retractable pegs intended to support their weight. This wasn't easy but was necessary because of the light construction. My belief is that the new construction airframes did not reproduce the cockpit adjustable Rudder Trim in order to simplify construction. In other aircraft such as the Chino A6M5, the fuel capacities are not original and the fuselage fuel tank is not installed. I suspect this is the most likely situation here as well.

Although they used the parts from several different wrecks recovered from Babo Island, there were only three A6M airframes reconstructed/built in Russia, all A6M3 Model 22's. That whole project was arranged and funded by the US-based company called Flight Magic (Museum of Flight), back in the 1990s. The work in Russia spanned 1994-97, and then each of the three airframes were later individually completed in the US (final systems work, engines, props, paint, etc.). The first of the three completed, which incorporated the most original parts, is the example owned/operated by the Commemorative Air Force Southern California Wing (c/n 3869, N712Z), which was first flown in 1998. The second of those to be completed is the example owned/operated today by Fagen Fighters WWII Museum (c/n 3858, N553TT), which was first flown in 2000. The third and final to be completed is the example owned/operated by The Flying Heritage & Combat Armor Museum (c/n 3852, N3852), which wasn't fully completed/flown until 2012 (partly due to extra work being put into rebuilding the cockpit and canopy section to match a WWII Japanese two-seat field-mod, completed in 2008).

Of the six authentic A6M Zeroes flying today, I'm not aware of any of them using skins that are any thicker/heavier than as originally used. Every example I'm familiar with, the no-step portion of the wings is most definitely observed, with pilots still having to be very careful to only step where they're supposed to. I do know that in some, there have been some "Americanized" cockpit modifications, such as expanding the distance between the seat and rudder pedals in some of them. I have noticed that, like you say, all of the flying A6M3 Model 22's have a ground-adjustable rudder trim tab, which I recall reading that they originally had cockpit-controllable rudder trim tabs on those examples. Where as the A6M3 Model 32 that is the subject of this thread (c/n 3148, N9940) originally had a ground-adjustable rudder tab, as it does today. It was actually found to have the tail section from another Model 32, c/n 3145.

 

[Ivan]

I was certain the flight adjustable rudder trim was a feature on the Model 22. I could find no photographic evidence of either configuration on the Model 32 which of course came earlier. One of the more common differences is the wing armament between the Model 22 and Model 32. There is no real reason there should be a difference, but the 99-2 long barrel cannon is more typically installed in the Model 22.
There were times when features between one manufacturer (Nakajima) lagged behind the other (Mitsubishi). Do you know if the restored Model 32 was originally a Mitsubishi or Nakajima airframe?

- Ivan.

 

[Bomber_12th]

Ivan, the history that I've read on this particular A6M3 Model 32 (c/n 3148) states that it was built by Mitsubishi, and completed on September 16, 1942.

Just within the last couple days I found this video on Youtube, which goes into some more detail about its rebuild. Bob and Dan Hammer, a couple of the gentlemen featured in the video, are the owners of the company, Legend Flyers, which performed the rebuild/restoration. In the video Dan Hammer states that about 200 original parts were incorporated in the rebuild/restoration, while the rest was built new. It also states that the aluminum used in the rebuild is in-fact a heavier grade than original (as you suspected), which added an extra 300-400 lbs to the aircraft. I suppose that doesn't matter too much in the performance envelope, since the original Sakae 21 engine produced up to 950 hp, where as the R-1830 mounted to the rebuilt aircraft produces up to 1,200 hp. I don't recall ever reading about the other A6M rebuilds using heavier grade aluminum, but I now suspect that may well be the case.

In the video, the videographer asks Dan Hammer about having gone to look over/research in detail the Ki-43 Oscar owned/operated by the Erickson Aircraft Collection. What Dan Hammer doesn't say/can't say in the video, is that the Military Aviation Museum, which owns the A6M3 Model 32, also owns two reproduction Ki-43 Oscars that were built by the same company as the Erickson Aircraft Collection's example, but were never fully completed/have remained in storage at the MAM for many years now. It would imply that MAM are likely thinking, or planning, on having Legend Flyers work on completing one or both of those MAM-owned Oscars as well.

With regard to A6M restorations, I'm now only aware of one additional example currently being rebuilt to fly, and that's being done by John Fallis in Louisiana (who previously restored a flying P-40N). It too is an A6M3 Model 32 variant, c/n 3285.

 

[Ivan]

Thanks for the video link.
I wonder if the extra weight of the replicas also accounts for the engine substitution.
I believe you are underestimating the power level of the Sakae 21 that was installed in the A6M3 and A6M5.
In my CFS1 thread on the A6M5, there is a page from TAIC on the Sakae 21. Note that the power levels are a bit higher than 950 HP, especially at low blower. One thing that is not mentioned on this page is that although the "WEP" setting is listed as +300 mm, there is no mention of "Overboost" which was a known feature of the Sakae engines. Even the Sakae 12 engine could exceed +300 mm on Overboost and there is an extract from combat reports in my thread on the A6M2 revisited. There is also the note on the TAIC page on the Oscar describing "very high Flash Performance" and the tendency of the Japanese pilots to ignore the limitations of their engines and get away with it.
This is why I believe there is much less difference in output between the Sakae 21/31 and the R-1830 than there would first appear to be.

- Ivan.

 

[Allen]

300 mm????

 

[Ivan]

Hello Allen,
The Japanese measured manifold pressure in mm of Mercury in relation to standard sea level pressure which is assumed to be 760 mm Hg.
Thus +300 mm Boost would be (300+760) / 25.4 or 41.73 inches Hg in American terms.
Attached below is an image of the gauge face from the A6M2.

The needle is sitting at the approximate zero mark which would be the appropriate reading with engine off at sea level.
Note that this gauge is sufficient to read up to maximum MP settings for the A6M2 (except for Overboost). For some strange reason, the Japanese chose to use the same gauge for the A6M3 and A6M5 even though they had higher boost limits. The fact that none of the gauges had changed caused a great deal of confusion when the A6M3 "Hap" was rebuilt at Eagle Farm and tested. The enging settings of Sakae 21 were assumed to be unchanged from that of Sakae 12 and thus the performance reports are not indicative of actual A6M3 potential. The manifold pressure limits were too low and even the RPM limits were too low. The net result was that the Eagle Farm A6M3-32 was probably more similar in performance to a good condition A6M2.

- Ivan.

 

[Allen]

Been into CFS2 and look at a number of things about Japanese aircraft but never knew they used mmHg. CFS2 uses cmHg when you hold the mouse over a Japanese manifold pressure gauge as well.

 

[Ivan]

The numbers on the gauges look like they are marked for cm, but the documentation on the aircraft will list manifold pressure in mm Hg.
There are a number of places where research done for CFS2 fell down a bit. You will note that the number ring around the Type 92 Compass found on the A6M series and other aircraft seems to be just a second indicator. In reality it was a manually adjusted marker to remind the pilot and did not move on its own. That is why it is so often found not in agreement with the compass face in the middle.
Attached is a page from the translated copy of the manual for A6M.
Note that the throttle settings are in mm Hg.

 

[Ivan]

Here is an equivalent page from the A6M3 Operations Manual. It has pretty much the same information but obviously only on the Sakae 21.
No, I don't read Japanese, but my dear Wife Anna Honey can do a pretty fair job if I ask her really nicely.

- Ivan.