"Mitchell Holman" wrote in message
...
®i©ardo wrote in news:3m0oj.15304$3m6.4485
@fe2.news.blueyonder.co.uk:

Indrek Aavisto wrote:
The third tail fin is unusual. Any ideas what it was for, and why it was
dispensed with on most models?

Cheers,

Indrek Aavisto


The first conversion from Avro Manchester to Lancaster made use of about
75 per cent of the Manchester's parts and assemblies - and the
Manchester had the additional central fin - hence this is probably that
aircraft, serial number BT308. Note that it lacks mid-upper and ventral
turrets.

The second prototype Lancaster, serial number DG595, flew in May 1941
and incorporated mid-upper and ventral (feature of the B Mk1) turrets
plus a newly designed and enlarged twin tail configuration which
discarded the central fin.



Since there was only one "upper" turret why was
it referred to as the MID upper turret?

There were some Lancasters that came with a mid under/ventral gun/guns.
Some squadrons removed them because of the
weight penalty relative to their use. Lancasters equipped with H2S
could not accomodate the lower guns/turret.

In the book LANCASTER by M. Garbett and B. Goulding
there is a photo of the second Lancaster prototype (as above) which
has the ventral turret in place. The comment is that it was
not persevered with being of no use on night raids.

Same book there is a cutaway drawing that shows the mid-lower turret
(two Browning guns). There is also on the same drawing the "mid-gunner".
Looks like he was expected to operate both, but that would be extremeley
difficult considering thr cramped mid-upper turret.

There is also a drawing by J. H. Clark of Aeroplane magazine showing
the "under turret" in the book Avro Lancaster The Definitive Record (2nd
Edition)
by Harry Holmes.

This still does not answer the question about the "mid-upper"
name but what the
heck.............................................. ...........