Consolidated LB-30/B-24A/MkI/II Liberator engines

[ThomasP]

As others have pointed out - the objects could be shields of some sort, or air flow directors.

Something I noticed, when I was looking for images of B-24s with the objects, I could not find any with the later oval engine cowlings. Does this mean that the objects were only fitted on early B-24s - and could the change in whatever lead to the new cowling design have something to do with why they were fitted?

 

[Shessi]

Hi Tom,
Yes these discs were only fitted to the early Liberators (LB-30, LB-30A, LB-30B, GR I, B II, C-87). When the later models came out they had the ovular cowling that had the cooler intakes at the sides.
Elsewhere have suggest a form or deflector/director which speeds up airflow to aid cooling. One thing against this is that the CAF LB-30 Diamond Lil, originally had these discs, but now doesn't. Unless the CAF have changed to different spec engines (which don't need these discs), then it should still need the discs, so why aren't they still fitted?

Shessi

 

[Snautzer01]

Hi Tom,
Yes these discs were only fitted to the early Liberators (LB-30, LB-30A, LB-30B, GR I, B II, C-87). When the later models came out they had the ovular cowling that had the cooler intakes at the sides.
Elsewhere have suggest a form or deflector/director which speeds up airflow to aid cooling. One thing against this is that the CAF LB-30 Diamond Lil, originally had these discs, but now doesn't. Unless the CAF have changed to different spec engines (which don't need these discs), then it should still need the discs, so why aren't they still fitted?

Shessi

Because owners change things.

Look at this eBay: North American B-25 Mitchell

And spot the differences.

 

[Simon Thomas]

I suspect the CAF will never deliberately operate in conditions conducive to icing, so any form of de-icing is not required.
The engines are rarely (never?) run at WEP, so cooling is not critical either.

 

[ThomasP]

Found this image of a post-war LB-30 (LB-30B model I think) operating with the Hellenic Airways (from Feb'48 to Nov'51) that was still fitted with the objects in question. So it seems they are probably important - whatever they are.

 

[Bretoal2]

A generally accepted idea in the mid-1930s was that this type of disc was essential for NACA cowlings to divert air flow towards cylinder heads.

A few examples among many others...

 

[ThomasP]

Do you know if they ever did the same with single engine fighters or light bombers?

 

[Bretoal2]

Do you know if they ever did the same with single engine fighters or light bombers?

At first sight : Letov S 231, Renard R32....

 

[EwenS]

Found this image of a post-war LB-30 (LB-30B model I think) operating with the Hellenic Airways (from Feb'48 to Nov'51) that was still fitted with the objects in question. So it seems they are probably important - whatever they are.

View attachment 736715

LB-30 c/n 55, serial AL557. TOC at Dorval, Canada 13 Oct 1941. Passenger conversion in 1945/46. After RAF service to Scottish Aviation Ltd as G-AGZI in Jan 1946. To Hellenic Airlines 1 Mar 1948 named Maid of Athens. To Morrison-Knudsen Inc in USA as N9981F Nov 1951. Reregistered N68735 Dec 1951 and then N29MK. Used in construction of DEW line. Crashed in Alaska 1958. Recovered 1990 and basic fuselage / wings last heard of being sold to Florida owner in 2001.

Edit - LB-30A & B had the short nose.

 

[Wurger]

Do you know if they ever did the same with single engine fighters or light bombers?

At first sight : Letov S 231, Renard R32....

Also the Romanian PZL P-11f had a similar but larger disk ( cover ) ...

the source: the net.

and the early PZL P-24A,B,C including the prototype ...

the pic source: the net.

 

[Bretoal2]

Also the Romanian PZL P-11f had a such similar disk ( cover ) ...

View attachment 736731
the source: the net.

and the early PZL P-24A,B,C including the prototype ...

View attachment 736732
View attachment 736733
the pic source: the net.

Yes, but on these engine installations "the thing" seems to cover and envelop the crankcase, while the initial question concerned a sort of plate !

 

[Wurger]

I agree. But it seems to be the development of the idea. Anyway here is a Waco 1939 plane with a such disk ..

the source: c7album/1939 Waco EGC-7 BRAZILIAN 01

the source: the net.

 

[ThomasP]

Interesting. Thanks for the info guys.

 

[ThomasP]

I was familiar with the 'salad bowl' fittings used on the Constellation & Super Constellation, but did not think that the largely flat objects on the B-24 were for the same purpose. I suppose it makes sense though, depending on the speed of the aircraft in question the airflow might cool the engine better if it is slowed down. A plate in front of the engine of the engine cowling would help creating a sort of pressure head of slower air, with the speed and volume of air passing through the engine compartment then controlled by the area of the opening between the edges of the plate and the opening and closing of the cowl flaps. It might cause more drag(?) in some circumstances but the improved ability to manage the engine temps could be worth it.

Below is the Super Constellation N6937C as it was in 2005. In theory it was in the same arrangement as it was when it originally entered service. Note the 'salad bowls' behind the spinners.

I wonder what the effects were in terms of difference in drag between the round cowling and plate arrangement on the early B-24/LB-30 and the oval cowling without the plate on the later B-24C onward.