Bristol Mercury - Variants

Variants

Note:

Mercury I

(1926) 808 hp, direct drive. Schneider Trophy racing engine.

Mercury II

(1928) 420 hp, compression ratio 5.3:1.

Mercury IIA

(1928) 440 hp

Mercury III

(1929) 485 hp, compression ratio 4.8:1, 0.5:1 reduction gear.

Mercury IIIA

Minor modification of Mercury III.

Mercury IV

(1929) 485 hp, 0.656:1 reduction gear.

Mercury IVA

(1931) 510 hp.

Mercury IVS.2

(1932) 510 hp.

Mercury (Short stroke)

Unsuccessful experimental short stroke (5.0 in) version, 390 hp.

Mercury V

546 hp (became the Pegasus IS.2)

Mercury VIS

(1933) 605 hp, see specifications section.

Mercury VISP

(1931) 605 hp, 'P' for Persia.

Mercury VIS.2

(1933) 605 hp.

Mercury VIA

(1928) 575 hp (became the Pegasus IU.2)

Mercury VIIA

560 hp (became the Pegasus IM.2)

Mercury VIII

(1935) 825 hp, compression ratio 6.25:1, lightened engine.

Mercury VIIIA

Mercury VIII fitted with gun synchronisation gear for the Gloster Gladiator

Mercury VIIIA

535 hp, second use of VIIIA designation, (became the Pegasus IU.2P)

Mercury IX

(1935) 825 hp, lightened engine.

Mercury X

(1937) 820 hp.

Mercury XI

(1937) 820 hp.

Mercury XII

(1937) 820 hp

Mercury XV

(1938) 825 hp, developed from Mercury VIII. Converted to run on 100 Octane fuel (previously 87 Octane).

Mercury XVI

830 hp.

Mercury XX

(1940) 810 hp

Mercury 25

(1941) 825 hp. Mercury XV with crankshaft modifications.

Mercury 26

825 hp. As Mercury 25 with modified carburettor.

Mercury 30

(1941) 810 hp, Mercury XX with crankshaft modifications.

Mercury 31

(1945) 810 hp, Mercury 30 with carburettor modifications and fixed pitch propeller for Hamilcar X.