Blenheim use 2 stage propellers?

[Buzpilot]

Why do Blenheim IV use 2 stage prop, didn't they use variable pitch propellers?
They were in regular use already in 1931-32, and Blenheim's first flight was in 1935.

[JG53Frankyboy]

Two speed propellers are historical correct for the Mk.IV!
Mk.V had CSP IIRC...

[Buzpilot]

Originally Posted by JG53Frankyboy

Two speed propellers are historical correct for the Mk.IV!
Mk.V had CSP IIRC...

Several sources indikate your wrong, do you have documents where it's stated?

The Bristol Blenheim was a British light bomber aircraft designed and built by the Bristol Aeroplane Company that was used extensively in the early days of the Second World War. It was adapted as an interim long-range and night fighter, pending the availability of the Beaufighter. It was one of the first British aircraft to have all-metal stressed-skin construction, to utilise retractable landing gear, flaps, powered gun turret and variable pitch propellers. A Canadian-built variant named the Bolingbroke was used as an anti-submarine and training aircraft.

From Bristol Blenheim in action;

The transition from biplane bombers with fixed undercarriage, fixed pitch propellers, and no flaps to the Blenheim with its retractable undercarriage, variable pitch propellers and flaps invitably led to problems...

And even a Blenheim PR Mk.I (L1348 ), prototype, was fitted with Rotol constant speed propellers, instead of DH-Hamilton propellers.

[IvanK]

Air Publication AP1530B Blenheim MKIV Pilots notes state 2 position variable pitch props only for MKIV
There are only 2 settings Coarse or Fine. No CSU was fitted.

AP1530B Section 2 Handling and Flying notes for the pilot. Introductory notes
(iv) Variable Pitch Airscrews - The airscrews are of the two pitch type i.e. Fine and Coarse. Fine pitch is always used for take off, for climbing on one engine and when approaching to land. Coarse pitch is used for all other conditions of flight, except when throttled well back when fine pitch may give smoother running"

Or purchase the DVD "Flight of the Blenheim"... there is specific discussion on the use of the 2 pitch prop there.

The MKI and MKIV were 2 position variable pitch props.

The equivalent publication for the MKV states CSU props for the MKV.

[Buzpilot]

Ok, that explain it, if variable and 2 step is the same.