ROYCE GRIFFON (65)
Review of the Latest ^Rolls-Royce Piston Engine : Classic Orthodoxy of Design Powers Yet Achieved
W HEN confronted with the Rolls-Royce Griffon for the first time, the facile result of an initial rapid appraisal is that the engine is nothing much more than a scaled-np Merlin, and, although there is doubtless a
certain amount of justification
for this view, it is not wholly one's investigations progress,
the impression is steadily merely a scale-up of an
strengthened that, far from existing engine, the Griffon
being is an
entirely new engine in its own right. probably be pretty accurate to hazard
It would, however, the assumption that
the Griffon eliminating
was born of all the snags
a desire and, at
to redesign the Merlin, the same time, increase
the capacity to meet the imminent demand engine whilst retaining the smallest overall possible.
for a larger dimensions
How well the men of Derby have succeeded in doing what they set out to do may be appreciated in part by a comparison of overall dimensions as between Griffon and Merlin, together with the respective swept volumes and
29.5m., and Merlin 2y.825in.
It would seem well-nigh
impossible, ,011 the overall dimensions
with such similarity of of the same basic type,
the swept volume of one should be 35.9 per cent,
area of the Griffon is 23 per cent, greater than Merlin, this having been achieved by increasing bore to 6oin. : a figure which is just about the optimum limit.
that of the the cylinder verging on
In view of this one is led to wonder what form the Griffon's successor will take; the useful limit of piston diameter halving been reached, one is forced to the conclu- sion that any largar capacity piston engine that Rolls have in m^nd to follow the Griffon will, of necessity, have more cylinders. It is an interesting speculation which naturally, and on precedent, takes it for granted that Derby do intend to produce a new and bigger orthodox engine.
Influence of the Racing '' Buzzard ''
piston areas. In three inches longer
overall length than the 78m.
the Griffon 65 is 8iin., of the equivalent Merlin,
the 66; Merlin,
overall heights are respectively, Griffon, 45111., and 43.675111., whilst the overall widths are: Griffon
Before going on to deal with the Griffon, a word should be said on the prevalent and somewhat erroneous assump- tion that the engine is a counterpart of the famous " R "
Buzzard racing engine which secured the Schneider
BEARING VENT PIPE
Trophy for England in 1929 and 1931, and
established a World's Speed Record. Certainly, the bore and stroke size are the same and so is the fundamental layout of the engine—but there
the similarity ends.
the lessons learned had their influence
can truthfully be said on the " R " engine on all the subsequent
Rolls gained ments
in the Merlin has resulted in which distinguish the Griffon.
the refine- The one
particular directly to amount of
the feriffon owes
the " R " is the crankshaft, development put into this
for the member
on the racing engine virtually towards making the Griffon the very beginning of its life.
paved theway a success from
Induction throat to impellers show- ing turbulence spider with fuel nozzles.
It is not, perhaps, gener-
Griffon was" originally de- veloped primarily to meet the Fleet Air Arm's specific- needs—low-altitude power,
of service, reliability, In the early days of