Whitley engine (cooling?) vent - solid or meshed?

[BikingLampy]

I'm partway through the Airfix 1/72 Whitley GR MkVII - Got as far as painting and assembling the engine nacelles.

 

Each one has a flap underneath that can be posed open or closed (part C05 x2)

 

The part has 4 long rectangular recesses in that could be simply pressings in the original aluminium; or alternatively they could be meshed over vents. If I was doing a scheme with a black underside it would be easy to bluff this, but as I'm doing the Coastal Command option with a white underside, if the recesses are meshed vents, then they'd show up as "dark" against the white paint. As the flap is directly behind the radiator, it would make sense that they could pass air open or closed - much like a Spitfire rad has an adjustable flap on the back to help avoid overheating on the ground, but then can be closed once airborne.

 

I've had a google around but not come up with anything useful - so any ideas...?

 

Thanks,

 

BL.

[dogsbody]

It's damned hard to find a good photo of this flap, especially on night bombers. If's it is down someone or something is in the way.

 

I'm going for a solid flap.

 

 

 

 

 

 

Chris

[RJP]

I haven't got the kit or the instructions but it certainly sounds like the rad exit flap.  If it's anything like you'd see on other RAF types, it's a solid piece of sheet metal and the four depressions would likely be strengthening.  If you look inside (ie forward) all you'd see is the radiator itself, forward of the flap.  

[Admiral Puff]

What RJP said. The radiator exit was variable, I believe to assist in keeping the engine at optimal temperature at any stage of operation. Closing it reduced the flow of air through the radiator; vice versa when it was opened. The flap could be set to maintain a particular engine temperature, e.g. it would be open wider during the climb, because the engine would be working harder and generating more heat, then closed in the cruise because the engine wasn't working as hard. It would be fully closed at start-up to bring the engine up to operating temperature as quickly as possible, but normally left open after shut-down to speed up the cooling process.

[BikingLampy]

Cool - good info - thanks all.

 

I'd guessed it was for varying the airflow through the rad, but the bit that concerned me was that if it was fully closed (and unvented), then there would be no airflow, so no cooling, but I guess as @Admiral Puff says - you'd want no airflow on startup to get the engines up to temp PDQ.

 

The pics are great - I'd seen the top one before, but I'm not so sure about the rest. Re the top pic - the far plane WL-J appears to have its tailwheel up on a block. Any idea why? Thanks...

[dogsbody]

Though the flap did close completely, I believe there was a small gap left at the rear to allow a small amount of air to pass through the coolant radiators and oil cooler.

 

 

 

Chris