Me.262 V9, W.Nr.130004: two questions...

[Alessandro Nati Fornetti]

Hello!
Maybe someone can help me to solve two matters on the 262 V9, W.Nr.130004 (VI+AD)...
- The first one is: two or four guns in the nose? All the pictures I have (in Smith & Creek's 4-volume set) seem to show the lower gun ports only, but the colour profiles in the same books have four ports.
- The second is about the small auxiliary intakes on the top, and slightly to port, of each engine nacelle: these appear on almost any 262 I've checked, except in the V9 profiles in the same books (the pictures aren't clear enough to tell).

Anyone has more infos..?

TIA!

Alessandro Nati Fornetti

[Richard T. Eger]

Dear Alessandro,

I'm going to try to answer your questions, if I can.

Regarding the number of cannons on the V9, I assume that you are looking at the photos on page 768 in volume 4 and the side view drawing on page 769. First off, as configured here, the aircraft is an Me 262 HG I. I think the lack of a visible upper gun port may be an optical illusion. The photo one up from the bottom hints at an upper gun. If you go on to page 770, you'll see the V9 later in life with the gun bay open and both upper and lower guns visible. As the HG I, the aircraft was being tested for increased speed, a role more likely that of a fighter than a bomber variant with its attendant bomb racks and bombs. So, either way, I'd say it was equipped with 4 MK 108's.

As for that mysterious opening on the engine hatch, my best guess is that that is an air inlet for planned cockpit heating. I do have a photo of a Jumo 004 with a cylindrical object with an inlet tube that would have mated up with this aperture in the cowling. The multi-hole rack above the engine immediately behind the engine hatch has one hole specified for cabin air. However, many engine photos don't show the device with the inlet. Putting two and two together, I think the inlet in the cowling was built in with the eventual use for cabin heating, something that few, if any, Me 262's actually had, to the best of my knowledge.

If someone else has a better explanation, I'd like to know the answer myself.

Regards,
Richard

[Roger Gaemperle]

Hello Alessandro and Richard,



I cannot add anything to the first question as I don’t have the book here with me. But regarding the second one:



I guess you mean the auxiliary intakes for the generators. These were not used for cabin heating but supplied cooling air to the generators, which were located directly below these hatches (tubes delivered the air to the genos). When they tested more powerful generators later (after more and more electrical equipment was installed) they first had some cooling problems as the air massflow was too low. It might well be that originally no hatches were foreseen for the Me 262 and that Messerschmitt only installed the hatches after they experienced problems with overheated generators in the V-9 (I would have to check some of the flight test reports I have at home).



Regarding cabin heating: The cabin air was taken directly from one of the last compressor stages. A tube from the compressor to the multi-hole rack was always installed (but in most cases just closed with a temporary cover as it was not used) in the Jumo004 as it was already expected during its development that pressurized (hot) air might be needed later for either cabin pressurization or heating. The cabin heating was tested as early as in spring 1944 but progress was slow. During testing problems were that it got either too hot or that the circulation was not good enough to de-fog/de-ice the whole canopy. Therefore they tested several different designs and finally they found a satisfactory solution.



Tubes were installed that were connected to the multi-hole rack on the engine side and to a big filter in the cockpit behind the instrument panel (the NASM Me 262, for example, has these tubes and filters installed). There are several reports of problems with the cabin heating, which was retrofitted to existing Me 262 in a larger scale about from March 45 onwards. Some pilot didn’t realize that the heating could be adjusted stageless (the lever was on the lower right side of the instrument panel) and turned it either fully on or off. The result was that it got far to hot (this was also experienced by a British test pilot after the war).



That’s all I can tell you without crosschecking my documents and photos at home. If you have further questions please let me know.



Regards,

Roger Gaemperle

[Alessandro Nati Fornetti]

Dear Richard and Roger,
Thank you for your replies.
About the cannons, I see the "hint" of an upper gun port in the pictures on page 768, but it isn't where it should be... It's a lighter spot higher, but slightly to the rear of the lower gun, while it should be perfectly lined.
The picture on page 770 clearly shows a closed upper port (you can see the oval panel), but I was wondering if this might have appened late in the aircraft's life.

The generator intakes... I had a closer look at the two centre pictures on page 768; you need some fantasy here, but I think I can make out the slight "bump" just where it should be. Wouldn't it be unsual if these intakes would appear on every Jumo-powered '262, EXCEPT the V9 as it was tested in HG1 configuration?

A pity we don't have better pics of the HG1 with the swept tail...

Cheers

ANF

[Richard T. Eger]

Dear Roger,

I was hoping you'd jump in on this, as you had studied the cockpit heating air system.

I spent about 20 minutes going back and forth through a myriad of photos, trying to find something on the Jumo 004 that would line up with that opening in the engine hatch. The problem was that only one photo showed a cylindrical device mounted near the top of the engine in the appropriate position for the tube extending from it to mate up with the opening. In all the other photos, this apparatus was missing, nor was there any identification of it in any of the Feb. 1944 JFM drawings in my possession.

What you suggest makes sense, but I'm just wondering why it failed to appear on other engines. That lack made me suspect it was part of the heating system, as this was not in use early on, although, admittedly, the thing certainly didn't look heating related. I can scan the photo for you for positive identification, if you like.

Regards,
Richard

[vzlion]

Re: Gunports. On page 96 of "Stormbird Rising" by Hugh Morgan there is a picture taken at Lechfeld post war that shows the gunports to good advantage. There are 4 gunports but the upper ones appear to masked off. It also looks like both the upper and lower guns are mounted even though the upper ports are masked off. There is a better quality picture on page 80 of "Messerschmitt Me 262, Dewvelopment, Testing, Production", by Radinger and Schick. HTH,


Walt

[Roger Gaemperle]

Dear Richard,

The Jumo drawings and photos usually don't show the generator as it was not part of the engine delivery package but had to be procured by the aircraft manufacturer. I found some discussions regarding this issue between Messerschmitt and Jumo in some original documents at the German museum in Munich.

That's probably also the reason why you found many photos of 004 witout generators. I attached a similar one that only has a temporary cover over the flange that was intended for the generator. On this photo you can also see the tube that delivered pressurized and heated compressor air to the rack (it comes out underneath the engine attachement point on the right side of the photo and turns 180 degrees before it is attached to the rack).

Regards,
Roger