Bristol Blenheim Mercury eng. cowl bracing close-ups (photo heavy)

[Tail-Dragon]

Going through my photo's. I realized that I had some good photo's of the Blenheim (and Lysander) Mercury engine installation and cowl bracing. These might help anyone doing Airfix's or Classic Airframe's Blenheim kits. The engine is a Mercury XX on a stand, and it was photographed at the Western Canada Aviation Museum in Winnipeg, Manitoba, Canada. I apologise for the quality, but they were taken with a cell-phone camera.

Hope they help someone,

Colin

[dogsbody]

Good stuff! Thanks.

Chris

[dogsbody]

Well said, Terry.

[Kari Lumppio]

Hello,

Great photos, thanks!

I have a question. Perhaps Terry or someone is able to answer. Did Canadian Mercury engines use baffles between cylinders? Finnish ones had them and they can be seen in photos too. Seems they were painted with some light colour, likely grey. In thie "baffles"-sense the old Airfix 1/72 Blenheim was closer to real life.

Cheers,

Kari

[Kari Lumppio]

Hello!

Photo below shows BL-131 engine maintenance March 7th, 1940. These long noses were built to RAF-standards though painted in Finnish AF colours. It arrived in Finland January 21st, 1940. The engine is as is from factory, no Finnish modifications. It does have the baffles between cylinders.

For those who do not know baffles are used on air cooled engines to force or guide cooling air around the cylinder cooling ribs. Installed on radials like Mercury the baffles block the room between cylinders and force all the incoming air through the cylinder head ribs. They are even more useful in hot climates than in cold. Baffles are not a means to warm engine and they have nothing to do with cabin heating.

For some reason almost all museum planes lack these baffles. IIRC also the Blenheim here in Finland.

I tried to find my photos taken from an original Mercury manual as IIRC they do have good drawings of the baffles but no luck yet. It is some years since I last looked them.

I should also have digital photos of Tampella drawing of said baffle. Tampella indeed manufactured and maintained Mercuries in Finland.

Cheers,

Kari

SA-kuva archive photo 5869 ( www.sa-kuva.fi )

[Kari Lumppio]

Hello agan!

For those who have Airframe Album 5, The Bristol Blenheim authored By Richard A Franks (Valiant Wings Publishing).

Look at the engine photos on pages 56-59. The baffles can be seen on many of the photos. Especially good one is p. 56 middle left. Photo from Bristol Aeroplane Company Ltd. On p. 58 left upper corner RAF Mk IV (confirmed by cocade) has light colored baffles between cylinders. Even finding this book was an effort. But if I would clean up the room I couldn't find anything any more...

All baffles in the photos are of light colour and do have a seam in the middle. They were pressed metal of complicated shape which filled tightly the area between cylinders. Save the two lowest ones which did have the similarly shaped oil sump between them.

Just noticed the upper left corner photo on p. 56. This is the Duxford flying example? It does have baffles with what looks like modern silicone rubber seals to go against the cowling. Just what is needed for good tight package to cool working engine.

Cheers,

Kari

[dogsbody]

From IWM:

with baffles:

http://www.iwm.org.uk/collections/item/object/205208837

http://www.iwm.org.uk/collections/item/object/205208673

http://www.iwm.org.uk/collections/item/object/205208707

From: http://www.404squadron.com/

http://www.404squadron.com/images/gallery/PL07700.jpg

http://www.404squadron.com/images/gallery/PL10877.jpg

From: http://www.bac-lac.gc.ca/eng

http://collectionscanada.gc.ca/pam_archives/index.php?fuseaction=genitem.displayEcopies〈=eng&rec_nbr=3581570&rec_nbr_list=3582876,3583176,3582135,3582875,3583177,3581570,3650413,3581563,3582073,3582413&title=Group+of++No.+8+Squadron+personnel+with++Bristol+Bolingbroke.+&ecopy=a063672-v8

Chris

[Walter Lindekens]

Hi guys,

Allow me to join in on the subject of the baffles - here's what a Bristol commercial brochure on the Mercury and Pegasus engines has to say on the subject :

And here are some photos that should be of interest :

And this is a link to a photo of a Boly clearly showing the baffles in place :

http://datav2.thememoryproject.com/image/4722_original.jpg

I would hazard a guess that the baffles should always be present on a Mercury but that in most restorations they have simply been lost. The Blenheim (Boly in fact) at the RAFM Hendon does have the baffles.

As for their colour, they show up very light in photos so natural metal perhaps?

Cheers,

Walter

PS Colin, thanks for sharing those great photos!

[Max Headroom]

Here is the port engine from the RAFM Bolingbroke with the baffles. Must admit i'd never have noticed them before.

Trevor

[dogsbody]

Awesome posting, Walter. Thank you.

Chris

[dogsbody]

The Blenheim at The Bomber Command Museum, at Nanton, Alberta also has the baffles fitted.

Chris

[mrp]

Here are what the baffles look like from the Mercury engine manual. There were obviously different shapes to fit around the engines.

Mark

[Walter Lindekens]

Thanks for that Mark, I know see where my scrap view of a baffle must have originated from. The drawings in the air publications are amazingly detailed, aren't they?

Cheers,

Walter

[mhaselden]

Found a nice pic of a 60 Sqn Blenheim MkI in India which clearly shows the baffles installed:

(Source: http://www.bharat-rakshak.com/IAF/Galleries/History/WW2/Misc/60-Squadron-ADDR.jpg.html)

Presumably the photo was taken pre-Feb 41 when 60 Sqn moved to Burma. By the time the Sqn made it back to India in Mar 42, it had re-equipped with MkIVs.

[mhaselden]

Minor thread drift but the first pic that Dogsbody linked at Post #10 shows an interesting feature related to the gun pack. There appear to be 3 (perhaps 4) partly-open hatches at the bottom of the gun pack.

I presume this was for access to the gun breaches (access to the ammo boxes was presumably via the bomb bay doors).

I don't recall ever seeing these doors in other pics of the gun pack.

Edited December 2, 2015 by mhaselden

[dogsbody]

I believe these are spent cartridge chutes. Just a guess.

Chris

[Walter Lindekens]

I believe these are spent cartridge chutes. Just a guess.

Chris

I would concur on that with Chris. Though why they would want to fit them beats me, they would only cause extra drag, wouldn't they?

Walter

[mhaselden]

Also, not sure why they aren't visible on other pics of the gun pack.

[dogsbody]

I just went through my few Blenheim refs but didn't turn up much. Just a couple of not very clear photos that may show similar features, but nothing as good as the IWM image.

Chris