A/c type change?...

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Member for

15 years 3 months

Posts: 923

hi,
can anyone tell me at what point/stage a a/c type being moded,actually changes type-eg- Blenheim mk 1,11,111,1V then the Bisley to mk V Blenheim.Is there a specific point where with all the mods-improvements call for a change in name?

regards
jack...

Original post

Member for

15 years 4 months

Posts: 957

The usual reason is not the accumulation of modifications but a significant planned alteration in role and/or capabilities. This is usually linked to a new engine or engine variant coupled with a significant alteration in the external shape. usually a new specification would be issued.

Thus we have the Lancaster Marks I,II and III which differ in the engine, whereas the marks IV and V offered new engines with major external shape changes, eventually becoming the Lincoln.

The approach differed with time: there's little doubt that the Hind, Audax, Demon etc would (later) all have been regarded as different marks of the Hart, but at that time a change of role called for a change of name, as names were tied to roles. The identical Vildebeest and Vincent were torpedo bomber and general purpose aircraft respectively. More recently, the Tornado F Mk.2 and 3 would certainly have had a different name to the bomber. In between, the Blenheim Mk.IV was originally named the Bolingbroke, the name eventually being transferred to Canadian-built examples, with the Mk.V being the Bisley, presumably because of the change of role.

The 20-series Spitfires were to be renamed the Valiant, largely because of the structurally redesigned wing coupled with the Griffon engine. One thing not to expect is consistency.

Member for

19 years 11 months

Posts: 1,988

Don't forget political expediency either - B-29D became the B-50 so that it could be perceived as a new model during a time of wholesale cuts with the conclusion of the war, rather than being a revision of an existing design

Member for

17 years 11 months

Posts: 2,024

The approach differed with time: there's little doubt that the Hind, Audax, Demon etc would (later) all have been regarded as different marks of the Hart, but at that time a change of role called for a change of name, as names were tied to roles.

Could there also have been a touch of sales pitch involved; Hawkers promoting them as a 'new' type, without the rigmarole of actually building one?

Member for

15 years 4 months

Posts: 957

Possibly, the Hartbees coming to mind particularly here. However, Hawkers showed no sign of this with other export sales, radial-engined Harts for the Swedes remaining as Harts, for an example.

At this time, the Air Ministry was pretty strict with its naming conventions, as the Vildebeest/Vincent and the Gordon/Seal examples show. There may be other examples, but the Hart family was pretty outstanding as the multi-role single airframe of the 1930s, so not a lot else spring to mind as possibilities.

When we get to the Hurricane/Hotspur/Henley, the airframe differences are enough to justify a new name anyway, but why Tornado/Typhoon? Surely not something that would have been thought suitable later.

Member for

16 years 7 months

Posts: 10,647

...eg- Blenheim mk 1,11,111,1V then the Bisley to mk V Blenheim.

Just to be politely pedantic, it's Mk I, II, III, IV etc in Roman numerals.
Important to highlight as 'II' is two and '11' is eleven, for example there was both a Vampire Mk II (development fighter) and a Mk 11 (T11 Trainer).
The British Roman numeral mark system was phased out mid to late 1940s by the Arabic numeral system that is still in use, example Meteor Mk III became known as the Mk 3.