Avro Lancaster Mark II

[Bf109_g]

Hi guys

I've been wondering, would the Mark II Lancaster have been more powerful if it had been equipped with Merlins instead of Bristol Hercules engines and also would it have been on par with the Merlin-engined Mark I and III's?

Thanks,

~ James

 

[antoni]

The Mk II designation is defined by the engines it is powered by, i.e., Bristol Hercules. If it was fitted with Merlin engines it cannot be a Mk II. The Mk III is basically a Mk I with Packard Merlins. In general Mk numbers were allocated for different powerplants including different versions of the same engine. As the Packard Merlin was built to metric standards and therefore parts were not interchangable a different Mk number was given. Likewise a Spitfire M XVI is a Spitfire Mk IX with a Packard Merlin. Even though both Mks were built in low and high back versions the major change to airframe did not result in a different Mk number being allocated.

 

[Downwind.Maddl-Land]

Antoni is correct '109. The Mk II Lanc was the same Mk I/III airframe equipped with (actually more powerful) 1,615 hp Bristol Hercules (Hercules VI or XVI) engines. Three hundred aircraft were produced by Armstrong Withworth. One difference between the two engine versions was the Herc VI had manual mixture control, leading to an extra lever on the throttle pedestal. These aircraft were almost invariably fitted with an FN.64 ventral turret and pronounced step in the bulged bomb bay.

The Mk IIs were almost exclusively used by the RCAF of No 6 Gp based around where I live in North Yorkshire; indeed my last (flying) Unit (RAF Linton-on-Ouse) was host to Mk IIs during WWII.

They were a 'mixed blessing' as – being air cooled radials - they were more robust than the Merlin engined versions and tolerated battle damage better. However, although significantly more powerful than their Melin engined brethern, the extra drag of the radial installation offset the greater power somewhat, and the rated power was at a lower altitude. Therefore they couldn't climb much higher than 16/17,000 ft; and in 1943 height meant LIFE. Consequently, they needed their greater battleworthiness as they caught more of the flak and fighters. However, with the Halifax the performance pendulum swung the other way! See my thread http://www.ww2aircraft.net/forum/av...ter-changes-between-inlines-radials-9865.html

 

[Bf109_g]

Thanks for that Downwind

So the Canadian Mk.II's were the only ones to have the ventral turret? (I think I remember reading that a Polish Lancaster squadron had them too).

 

[Downwind.Maddl-Land]

No, most Mk IIs had it, certainly, and all Mks were provisioned for it but most of them didn't have it fitted, mainly because it was:

1. Near to useless, especially at night; apparently you could see damn-all through the periscope and tracking was next to impossible by day and the gunner usually became airsick!

2. Heavy, caused drag and reduced performance; this may have been why the Mk IIs retained it as most of them had bulged bomb-bay doors and the FN 64 faired nicely into the back of those and didn't cause as much drag in that configuration.

3. H2S was far more useful and the FN 64 ventral position provided a just peachy location for it.​

As ever, when there's a war on you can't keep things 'Neat and Optimal' and all sorts of 'odds and ends' of configurations appear. I'm sure that there would have been Mk Is and IIIs that had it and some Mk IIs that didn't. Similarly, I am prepared to bet that the FN 64 was on some aircraft in a sqn (let alone a Gp) and not on others. It's therefore entirely possible your Polish sqn may have had them.

The Canadians seemed (very sensibly IMHO) to have a 'thing' about ventral defence and probably requested that the FN 64 were retained on their production aircraft. When later re-equipped with Hercules powered Halifaxes, they insisted on the Preston-Green ventral position being fitted; did 6 Gp have earlier knowledge of the Sträge Musik threat one has to ask?

 

[Bf109_g]

We might never know if 6 Group did have prior knowledge of it, Downwind

 

[antoni]

Only early production Lancasters were fitted with ventral turrets. Only 300 Squadron in the PAF flew Lancasters (both Is and IIIs) and none of the photographs I have feature a ventral turret.

 

[peterpoet]

Any information esp photos of 300 squadron would be appreciated by friend of W/Cdr Teofil Pozyczkas son to be passed on to him.