I’m trying to make sense of the following passage from some Lancaster pilot’s notes, attributed to May 1944.
It concerns the carburettor heat controls and presumbably means that early Lancs had a hole under the engine nacelle and later ones (with the mod) had a hydraulically controlled flap. Can anyone confirm this was the case and when it was introduced? My guess would be with the MkIII and the Packard Merlin’s different carburettor but I’m sure someone knows a bit more detail!
Here’s the extract;
24. Carburettor air-intake beat control — A single lever for the hydraulic operation of all four carburettors’ warm air intakes is on the left of the pilot’s seat.
When Mod. 1198 is fitted the control has 3 positions, COLD, WARM and HOT (emergy.). If the control is at WARM, air is then drawn into each engine through the warm air-intake inside the bottom engine cowling. When moved to HOT, a flap in the bottom engine cowling is opened by an electro-pneumatic ram and allows hot air to be drawn from the radiator to the engine. The WARM position may be used to prevent the formation of ice when flying in icing conditions, but this will reduce the range (see para. 49 (iii)).
If the flight is continued, instead, in COLD until carburettor icing becomes evident, the HOT position should then be used, but only until the ice his cleared.
If Mod. 1198 is not fitted, there are only two positions COLD and WARM, but the latter position should be regarded as having a similar function to the HOT position when the 3-position control is fitted, as air is drawn from the radiator to the engine through a hole in the engine cowling when the control is at WARM.
Thanks!
Mark P
By: posart - 3rd February 2018 at 10:03
Thanks Peter,
So if that flap uses a pneumatic ram then it seems to tally with the description of Mod. 1198. The April 1943 pilot’s notes talk about the carb heat being hydraulically controlled, (as do the MkX notes), so I’m trying to understand how this flap fits in with all that and ultimately whether this was a flap fitted to early Lancasters or whether it was introduced in late 1943. I’ve been trying to find some early Lanc photos of this area but as you can imagine, it’s not the most obvious place to stand when photographing them!
By: Peter - 3rd February 2018 at 03:15
Thats the one for carb heat as it is operated from a vertically mounted Pneumatic ram
By: posart - 2nd February 2018 at 06:28
Thanks for the replies so far, I note that the MkX pilot’s notes only refer to two positions, COLD and HOT, which might suggest this three position mod didn’t last long? Anyhow, from an artist’s point of view, can anyone confirm if the light panel indicated in the photo below is a moveable flap and if so, is there any evidence of this flap being fitted to early MkI Lancasters or could this be part of Mod 1198 introduced maybe autumn 1943?
[ATTACH=CONFIG]258666[/ATTACH]
By: Bradburger - 31st January 2018 at 21:01
I just took a look at the Lancaster III Pilots Notes dated June 1943, and there is no mention of a carb heat control in them!
Oh hang on a minute, I see a handwritten note – ‘Air Intake, Cold’ and note it is referred to as ‘Air-intake heat control’.
Cheers
Paul
By: Bradburger - 31st January 2018 at 20:47
Mark,
Not that it is probably much help, but this is what the paragraph on the carb heat control says in A.P.2062 A & C Vol. I – Lancaster MK.I & III (dated April 1943), under the Engine Controls section of CONTROLS AND EQUIPMENT FOR PILOT.
(See attachment)
Looking at the CoG and Loading charts, there is no mention of modification 1198 in the Modifications weight list.
(The highest mod listed. is no.913 ‘Introduction of downward vision blister’, approved in August 1943).
So it’s safe to assume it was introduced after this time period.
Cheers
Paul
By: nx611_1945 - 31st January 2018 at 20:44
The carb ‘trouser legs’ have a flap on them to either draw air from the ducts on the sides of the engine cowling or from under the engine inside the cowling.
The electro-pneumatic ram opens and closes the rad shutter which is the large flap under the engine aft of the radiator. This flap allows the air that blows through the rad to exit the cowling when the shutter is open or keeps the air inside the cowling if the shutter is shut.
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January 31, 2018 at 7:21 pm