States. The 60-degree V- 12 design (like a Ferrari),
with its seven main bearings, was liquid-cooled. The
Merlin was mass-produced for more than 25 years, to
the tune of about 150,000 units. The last aviation
application I could find was, ironically, in the 1954-
era Spanish-produced Bf 109! A variant was also used
to power tanks.
Early Merlins were rated for 1,030 hp at a gear-reduced 3000 rpm, weighed 1,320 pounds with
gearbox (the same as the gross weight of a modern
light-sport aircraft), and had service lives in the
200—400 hour range. That was of little concern; in
combat, airplanes rarely lasted that long. Cost to the
War Department was purported to have been £ 2,000
in 1941.
That was then.
Nowadays, with these Merlins becoming septuagenarians, more is expected. To get better perspective
on what some of these engines are doing today, I
talked with Mike Nixon, who has built the fastest
Merlins in the world (including engines for multiple
Reno Air Racing Unlimited winner Dago Red and the
When the Merlin engine was
eventually installed in the P- 51,
the resulting Mustang was the
machine the engineers at North
American had always known it
could be.
past two years’ Reno champion and the Unlimited
racer with the most wins, Strega). He’s been building
winning Merlins for nearly 30 years, and Mike says
he works on more than half the flying Merlins in the
United States.
GOOD, BUT NOT PERFECT
Mike is well aware of what Merlins can do and what
they can require. Like most hot-shot engine builders
who experimented with these big V-12s, he tried various combinations of clearances (and went back to
original factory specs), gearboxes, boost, and compression ratios. Strega is surprisingly mild, on paper,
running “just” 130 inches of manifold pressure (some
racers run 145) into 5.7-to- 1 compression cylinders.
Though the 6.0-to- 1 compression ratio is more
