Question about Erla cowling for late Me 109

[klemchen]

Hello,

reading the thread "Very interesting Bf 109 G-10" brought back to my mind an old question:
Some time ago somebody showed me a Mtt. drawing comparing the longitudinal bottom lines of the Me 109 G cowling with those of the "Me 109 K". The latter appeared to be about 1 or 2 cm lower than the former over practically the whole length. Since the lower cowling of the "Regensburg K-4" was based on that of the Me 109 F/G (with a deeper Fo 987 oil cooler inserted and the so-called chin bumps added), "Me 109 K" could possibly only refer to the G-10/K-4 cowling by Erla, the lower part of which was an entirely new design too (e.g. asymmetric vs. symmetric). The oil cooler on that appears to be distinctly shallower, and its front opening sometimes is claimed to be wider.
But if the Erla cowling was indeed deeper and, moreover, if the same Fo 987 oil cooler was installed in the same position with respect to the engine as it was on other G-10/K-4s, from outside it would appear shallower, and its front opening might give the impression of being wider because of its "flatter" proportions.
Now I suppose that just this was the case. For it is hardly imaginable that at that stage of the war the logistics situatiuon would be made even more difficult by introducing another type of oil cooler for the Me 109, production of which was to be discontinued anyway in the following year. If Erla were making their oil coolers themselves they might as well take a new design, but by the different structure of the designations for oil coolers in the replacement parts lists from those for other airframe parts I guess that radiators were not made by the airframe builders but by special other producers.
There is, although only weak, some evidence that my conjecture is correct: In the front view on a well-known Mtt. general arrangement drawing of the Erla G-10 the front opening of the oil cooler duct appears to be about 46 cm wide. This agrees pretty well with the Fo 870 oil cooler duct of earlier Me 109 Gs, which was 462 mm wide at the bottom and 448 mm at the top, and I think the Fo 987 was just deeper but not wider. The trouble with that famous Mtt. drawing is that while it is surprisingly precise in some respects it is quite crude in others, so the width of the oil cooler could just as well be due to crudeness.
Now my question to the experts is whether anybody knows any further facts which would support or refute my presumptions.

Best wishes,
klemchen

[Eduardo]

Hello Klemchen

I´ve seen a photo of a G-10 (Erla built) with an open lower cooling that clearly shows an Fö 987 radiator inspite of the diferente type of lower cooling without bulges and deep radiator case.

Eduardo.

[Graham Boak]

The Mtt design will have been chosen to provide the desired level of cooling. If the Erla design had the same width but a shallower opening, then the cooling would not have been as efficient and the engines overheated.

I'm not convinced that this can be the answer to what you are seeing.

[D.B. Andrus]

Here a couple of shots of an apparent Erla-style G-10 oil cooler housing in current use. Looks like the design is workable.

Best Regards,
D.B.

Photographer unknown - captured from the internet.

[RolandF]

"Red 7" D-FWME is a re-built from a Spanish Buchon brought up to the standards of a G-4. The engine is a DB 605 A, so I´m sure this one is no reference.

Regards

Fran

[veltro]

Personally, I have always had some doubts about the supposedly greater depth of the Fo 987 on the Erla G-10 rather than on the MTT K-4...

The images available doesn't do much to change this impression...

This is the radiator on the K-4:





And here it is on the G-10 produced by Erla:





I cannot judge millimeters-wise, but it doesn't seem so different.

Maybe the difference was in width, due to the clearly different and more straight profile of the lower cowl designed in Leipzig...



I instead agree on the lack of consistence in quality and precision of the alleged MTT "technical" drawings, and IMHO, until original plans from both Erla and MTT will surface, every discussion could only be based on impressions and not true data.

Hope this helps.

[D.B. Andrus]

Originally Posted by RolandF

"Red 7" D-FWME is a re-built from a Spanish Buchon brought up to the standards of a G-4. The engine is a DB 605 A, so I´m sure this one is no reference.

Regards

Fran

The "G-4" does have not a standard 605 A oil cooler housing. The shape of it are much more in line with the Erla G-10 model than MTT. My supposition, and that's all it is, being that the restorers/converters wanted to use a Fo 987 and still have more of a G-4 look than a MTT housing would provide.

That's my story, anyway.

Best Regards,

D.B.

[harrison987]

Hi D.B.

"Red 7" has the standard G6 (DB605A) cowling (it is not anywhere near the G-10 type). I think you are confusing the size of the oil cooler intake, which is in fact, of the larger type. However, the entire cowling cover is not G-10. What makes a G-10 cowling are the larger chin bulges, which were added to accept the larger coolant lines for the DB605D...it is not the size of the oil cooler intake.

There is nothing on Red 7 that makes the cowling a G-10 type.

When the K-4 had the chin bulges missing, it was because the entire cowling was made larger and streamlined (as opposed to manually adding chin bulges), to compensate for the coolant lines. The difference is so minor, it is not noticeable in photos.

Mike

[D.B. Andrus]

Originally Posted by harrison987

Hi D.B.

"Red 7" has the standard G6 (DB605A) cowling (it is not anywhere near the G-10 type). I think you are confusing the size of the oil cooler intake, which is in fact, of the larger type. However, the entire cowling cover is not G-10. What makes a G-10 cowling are the larger chin bulges, which were added to accept the larger coolant lines for the DB605D...it is not the size of the oil cooler intake.

There is nothing on Red 7 that makes the cowling a G-10 type.

When the K-4 had the chin bulges missing, it was because the entire cowling was made larger and streamlined (as opposed to manually adding chin bulges), to compensate for the coolant lines. The difference is so minor, it is not noticeable in photos.

Mike

Mike, please note "oil cooler housing" in my post.

Best Regards,
D.B.

[klemchen]

Hello,

many thanks to all who have answered. The photos of Ferdinando D'Amico are amazing. One clearly is showing the asymmetry of the lower Erla cowling, and others confirm that the front section line of the movable part of the cowling had an almost (or even strictly) straight part at the bottom and that there was no vertical little strut in the front opening of the oil cooler.
Now the upper cowling of Red 7 seems to be definitely of early G type, but about its lower cowling I am not so sure. Its oil cooler case resembles that of the Erla G-10/K-4 and the straight part at the bottom of the front section line seems also be there, while it looks curved on early Gs seen from about the same angle. So it almost seems that it was something like a symmetric adaption (with starboard half mirrored) of the lower Erla cowling. Anyway, Red 7 should be called simply a G; the antenna wire of the G-4 was lead into the fuselage further aft. (Actually this was the only crucial external difference between G-2 and G-4.) Let me add that I still think that Red 7 is a marvelous piece of restoration.

Best wishes,
klemchen