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Lancaster Merlin carb intakes - all the same size?


Simon

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Hello everyone

 

I have a quick question about the carb intakes on Lancasters. Were they all the same size across the four engines? I've seen photos of the BBMF Lancaster PA474, which seems to have longer ones on the outboard engines than on the inner. Link here to a photo which shows them.

 

NX611 Just Jane seems to have the same different sized ones too - photos here and here. Does it depend on the version?

 

Thanks

 

Simon

 

EDIT - on Merlin engined versions, not the Mk.II.

Edited by Simon
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Hello, Simon

I made a cursory search through the The Lancaster story book by Peter Jacobs and the first photo with a somewhat large intake on outer engines depicted Aeronavale Lancaster, so possibly this was a post-war modification. Will make a more thorough search later, but probably someone with better knowledge will provide an answer by then. Cheers

Jure

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On Pete's photos, the inboard one seems more curvy than the outboard one, but that may be some trick of the light or angle or how much coffee I've had...

 

Seems to me that the Belcher bits replacement nacelles (1/48) instructions mentioned something about a difference between the two positions, but I'll have to look.

 

bob

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Hi

I searched for the explanation about the size of intakes but, unfortunately, no joy. On the top of that, on the photos of museum Lancaster Mk.X KB944 the intake on no 2 engine is evidently smaller than the one on no 1 engine.

http://flickrhivemind.net/Tags/kb944/Recent

The same is suggested by Belcher Bits photos of replacement nacelles and instructions for that set.

http://www.belcherbits.com/lines/148conv/bb15.htm

http://www.belcherbits.com/images/148conv/bb15inst.pdf

On WWII photos there seems to be no difference in size, though. If I would have to speculate (and in an absence of satisfactory explanation I have to) I would repeat my assumption about post-war modification. Also, judging by the photos, there is no firm rule about what size of carburetor intake goes where. Not much, but I hope it helps. Cheers

Jure

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Many thanks indeed for all the replies. I did come across these photos of post-war SW377 of 203 Sqn and a wartime photo of R5868 'S for Sugar'.

 

SW377 seems to have identical size and shape, whereas wartime R5868 has same size but looks like differently shaped ones. As Jure says, seems there's no firm rule about shape/size! I guess wartime wear and tear meant some were repaired on site as an when necessary, which may explain the shape differences? I noted that Freightdog does enlarged intakes for Lancasters with Merlin 24 engines. Could a Lancaster have a mix of earlier Merlins and Merlin 24 engines?

 

Regards


Simon

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Hello

Some Halifaxes II and V had both Merlin XX and Merlin 22 engines installed in pairs. These planes had both three and four bladed propellers, quite a sight. I have never seen anything like this on Lancasters, but two pairs of Merlins of different versions sounds plausible, provided both marks came from UK. Cheers

Jure

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Not sure if this is definitive or not, but I went to the IWM photo archives and looked at all of the Lanc photos that showed both the inner and outer engine nacelles; they all showed carburettor intakes that appeared to be  the same size and shape- all of the photos were of wartime, not postwar aircraft, and none were French Lancs, which do appear in some photos to have longer intakes on the outer engines. I have no idea why this might be- maybe the proximity to the undercart in the inner nacelles or some structure or equipment peculiar to the inner nacelle might have some bearing; but if so, why not on the wartime Lancs? Those frivolous Frogs and their airplanes! That's as far as my thinking takes me, guys!

 

Mike

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Since this seems to be a postwar question, could it be that the increased size of the intake was intended to accommodate a tropical dust filter?

 

Not to subvert the topic too much but there have been references to enlarged rads on postwar machines as well. Same reason, tropical use?

 

I have looked but never been able to nail it down.

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Re Halifaxes: I have not seen nor heard of any examples with mixed Merlin XX and 22.  Before Merrick's latest book I'd have thought any such would be obvious, because of the difference in the radiators, but apparently some Merlin 22s ended up in airframes with the Gallay radiators.  It surprises me, but that's what the man wrote.  So theoretically it could be possible to mix Merlin variants without any external indication.  However, this has nothing to do with the 4-blade props, which were installed to reduce vibration and give slightly more thrust.

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Thank you, Graham. About post-war Lancaster book; if you mean Avro Lancaster in military service 1945-65, published by Flightcraft, it contains photos of Lancasters with carburetor intakes of all sizes in all possible combinations. One observation about the photos which may or may not be significant: RAF and RCAF planes tend to have bigger intakes installed on inboard engines. Conversely, Aeronavale aircraft usually have them other way around. Whether this had been due to specific French demand or Lancaster modifications varied with time I have no idea. Cheers

Jure

Edited by Jure Miljevic
Edited for spelling
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Thank you for all the additional replies everyone. Seems to be two sizes of intakes, some with larger ones inboard and some outboard, but it seems to be a postwar modification.

 

As a supplementary question, this Lancaster:

 

IMG_0006.jpg

 

has a small perspex fairing under the nose, below the bomb aimer's bubble, partly hidden by the pitot tube. I'm sure I've seen this mentioned before, but can't remember where. What is it for?

 

Regards

 

Simon

Edited by Simon
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it's an observation blister of sorts.

 

Quote

Of note in the photos of the aircraft are features such the large, later style, bomb-aimer's 'bubble' with IFF Z' equipment and a Perspex downward visibility blister under the nose in place of the bombaimer's window was also fitted. These were open at the rear and actually were not draughty, as warm air was pulled down from the cabin. However, some bomb-aimers reported suffering airsickness from lying with their head in the blister looking down and to the rear to guard against attack. A cockpit blister was fitted on the starboard side only and a 'Window' chaff chute on the starboard side of nose

 

Discussion here: https://ww2aircraft.net/forum/threads/lancaster-squadron-leaders-marking-question.11475/

Edited by elger
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