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Silver Sunderland details


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Some photos of early Sunderlands, including L5802 which I'm building from the Kits-World sheet, show the cooling gills for the engines in a similar dark shade to the front of the cowling which is usually portrayed as a dark coppery tone.

 

Does anyone have any idea if the cooling gills were the same colour?

 

For example the prototype

 

large_000000.jpg?action=e&cat=photograph
INTER WAR BRITISH AIRCRAFT. © IWM (ATP 9278C)IWM Non Commercial Licence

 

large_000000.jpg?action=e&cat=photograph
INTER WAR BRITISH AIRCRAFT. © IWM (ATP 9499C)IWM Non Commercial Licence

Edited by rossm
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They could be.  Both the front ring and the gills are part of the ducted air system for cooling the engines, over time the greater heat at the front may discolour the front ring more? 

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14 hours ago, rossm said:

Some photos of early Sunderlands, including L5802 which I'm building from the Kits-World sheet, show the cooling gills for the engines in a similar dark shade to the front of the cowling which is usually portrayed as a dark coppery tone.

 

Does anyone have any idea if the cooling gills were the same colour?

 

For example the prototype

 

large_000000.jpg?action=e&cat=photograph
INTER WAR BRITISH AIRCRAFT. © IWM (ATP 9278C)IWM Non Commercial Licence

 

large_000000.jpg?action=e&cat=photograph
INTER WAR BRITISH AIRCRAFT. © IWM (ATP 9499C)IWM Non Commercial Licence

Bear in mind the following from Sunderland I Aeroplane - July 1938, Version I  (manual)

 

  "76. Exhaust Collector Rings" form the "Leading Edge" of the cowling, and independently supported

from the engines

As I understand it, the Collector rings were Stainless steel and only started looking "Coppery" after some use.

 

As far as the Cowling gills, again from the Above Manual: (yes I know 75 should come after 76 :D)

 

"75. Controllable gill cowling is fitted to each engine and forms an extension to the cowling proper"

 

I doubt that the gills were Stainless steel, but rather some form of Aluminium alloy coated with Aluminium paint/dope.

That being the case  IMHO it's very probable that the air passing over/around engine (Not Exhaust) could cause

discolouration to the  gills after a period of time.

 

The Sunderland Mk I (at least) flew with the Pegasus XXII engine (again from manual), and the operating temperature

may have something to do with it?

 

HTH

 

Alan

 

 

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Hi Ross,

the cowl rings are 'burned' metal, they started life looking much like the rest of the airframe, i.e. shiny (stainless steel?)

 

and NEVER copper.

As malpaso has said ducted air cooling probably has something to do with it.

Was going to suggest waiting for LDSModeller.....and lo and behold he appears......'tis witchery I tells 'ee...witchery!

Paul

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Thanks everyone, my understanding from a post by Edgar was the exhaust collector rings were cadmium plated https://www.britmodeller.com/forums/index.php?/topic/32192-bristol-engine-collector-rings/&tab=comments#comment-346017

 

He was, of course, quoting official documents and we know practice can depart from theory.

 

I have my own special brew based on Tamiya Bronze as seen on my Beaufughter below. The silver fronts are often seen in photos, including the one of L5802 that I am working from but my understanding of the construction is not good enough to explain why. It just doesn't quite seem right to use the burnt colour on the cooling gills - maybe Tamiya Metallic Grey as an 'unburnt' shade ?

 

To get it to the Plymouth show tomorrow I'll be leaving everything in silver - it's good enough to exhibit otherwise - and hope no-one notices.

 

Beau_web3.jpg

Beau_web2.jpg

Beau_web1.jpg

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These are brand new aircraft.   If the cowling gills were so discoloured after such a short time, then there would be similar signs on the front of the nacelles which were exposed to the same airflow.  If the gills were made of the same material as the rest of the aircraft and painted with the same paint, they would appear the same.  Therefore the gills were made from a different material.

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12 hours ago, Graham Boak said:

These are brand new aircraft.   If the cowling gills were so discoloured after such a short time, then there would be similar signs on the front of the nacelles which were exposed to the same airflow.  If the gills were made of the same material as the rest of the aircraft and painted with the same paint, they would appear the same.  Therefore the gills were made from a different material.

What materiel would you suggest?

The issue also is the Collector rings had pure hot exhaust, where as the the gills had only

air from around the engine, big difference in temperature.

The question also has to be asked why is it that later Sunderland Marks with white paint

didn't have the same issue?

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10 minutes ago, LDSModeller said:

What materiel would you suggest?

The issue also is the Collector rings had pure hot exhaust, where as the the gills had only

air from around the engine, big difference in temperature.

The question also has to be asked why is it that later Sunderland Marks with white paint

didn't have the same issue?

The white Sunderlands used heat resistant paint - Paul Lucas gave the details in MAM Jan 2009 - ICI anti glow paint 143/2037 or Jenson & Nicholson anti glow paint - stores ref number for either was 33B/528.

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15 minutes ago, rossm said:

The white Sunderlands used heat resistant paint - Paul Lucas gave the details in MAM Jan 2009 - ICI anti glow paint 143/2037 or Jenson & Nicholson anti glow paint - stores ref number for either was 33B/528.

Around the Collector ring yes - Later versions of Collector ring,

I doubt seriously the same type of paint used on the actual cowling and gills,

because you also would have to paint the rest of the nacelle and wing areas

where the heated air would flow from the engine past the gills where discolouration

presumably would occur too

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22 minutes ago, rossm said:

The white Sunderlands used heat resistant paint - Paul Lucas gave the details in MAM Jan 2009 - ICI anti glow paint 143/2037 or Jenson & Nicholson anti glow paint - stores ref number for either was 33B/528.

Coastal Command used a white paint on white painted aircraft ie Sunderlands; Wellingtons. They also used a black paint on Beaufighters. Bomber Command used a black paint on their night bombers that were fitted with Bristol engines.

 

 

Chris

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I just can't see how the air going past the cylinders would get hot enough to discolour the cooling gills, especially on the outer surface.

 

 

Chris

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15 hours ago, rossm said:

 

 

To get it to the Plymouth show tomorrow I'll be leaving everything in silver - it's good enough to exhibit otherwise - and hope no-one notices.

 

 

Considering that you put that up here, I'm sure no one will notice  🙄

 

I can't believe it's discoloration, way too even for that, more likely unpainted different material

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  • 2 weeks later...

Perhaps, in the 1st photo the exhaust ring and gills are are unpainted stainless steel, and in the 2nd photo they have been painted with the only hi-heat paint available, stove enamel black.

 

Wild speculation,

 

Garry c

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5 hours ago, Garry c said:

Perhaps, in the 1st photo the exhaust ring and gills are are unpainted stainless steel, and in the 2nd photo they have been painted with the only hi-heat paint available, stove enamel black.

 

Wild speculation,

 

Garry c

 

Why would the cooling gills be made od stainless steel? They were probably just duralumin, the same as the cowling panels. They didn't see that much direct heat. The exhaust collector ring was another story. This was in direct contact with hot engine exhaust gases, at a temperature of 800+ degrees Fahrenheit and soon darkened through heat staining.

 

 

Chris

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14 hours ago, dogsbody said:

 

Why would the cooling gills be made od stainless steel? They were probably just duralumin, the same as the cowling panels. They didn't see that much direct heat. The exhaust collector ring was another story. This was in direct contact with hot engine exhaust gases, at a temperature of 800+ degrees Fahrenheit and soon darkened through heat staining.

 

 

Chris

Hi Chris, I agree with you.

 

Further re-reading of The Sunderland Mk I manual, I quoted above, states that the "Gills" are made from a "light Alloy".

 

Regards

 

Alan

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1 hour ago, LDSModeller said:

Hi Chris, I agree with you.

 

Further re-reading of The Sunderland Mk I manual, I quoted above, states that the "Gills" are made from a "light Alloy".

 

Regards

 

Alan

Thank you all for persisting with this, although the model was on display at the Plymouth show I have still not painted exhausts or cooling gills. The exhausts will be heat stained metal - the best I can do for an uneven brownish-bluish tinge but I'm still undecided on the gills although coming down towards darkish silver grey to represent unpainted metal while matching the tone in the photo.

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