Some interesting facts that I read on the Sanders website that I thought you guys would enjoy reading: "One second on the course with Dreadnought"
August 28, 2006
Story by Tom Fey
Photos by W J Pearce
At a race weight of 6.25 tons, the trick Pratt & Whitney R-4360-63 powered T.20 Sea Fury
“Dreadnought” is truly the big kid on the air racing block. Built, owned, and flown by the late
Frank and sons Brian and Dennis Sanders, this two-seat masterpiece has turned the pylons as
fast as 458.9 mph by virtue of the clean, highly detailed airframe and the 3,800 horses that tread
within her custom cowling. Dreadnought has won the National Championship Reno Air Races
twice, and finished second 13 times. To simply call this airplane large and fast, while certainly
accurate, diminishes the fantastic complexity required to attain such impressive performance. If
you could examine a single second of time while Dreadnought is hard at work, engine at 3000
rpm and 72 inches of manifold pressure, just 70 feet off the deck at 450 mph on the Reno
course, what would you find?
In that one second, the thundering, 4,290
lb R-4360 radial has gone through 50
revolutions, with each of the 28 finelyfinned
cylinders firing 25 times. Inside
each cylinder of 156 cubic inch (2.6L)
displacement (same as the entire V-6
powerplant in a C class Mercedes-Benz)
a piston the diameter of a coffee saucer
has transmitted close to140 horsepower
to the master rod. Seven cylinders are
linked to each master rod, with each of
the four master rods adding their own
900+ horsepower to the crankshaft.
Seven hundred power pulses, one pulse
for each 9.5° of propeller arc, have been transmitted to the six foot long, one-piece, four throw
steel crank. Each piston has traveled 50 feet in linear distance, changing direction 100 times per
second, with the total linear travel of all 28 pistons adding up to a ¼ mile. Each sodium-filled
exhaust valve the diameter of a beer can (2.5 inches) has required 2.1 tons of initial force to
open the port to expel the 1600° F gasses into the 14 exhaust stacks specifically choked to
maximize jet thrust from the exhaust. The single-stage supercharger rotor, 14 inches in
diameter, has spun 348 times, delivering 98 cubic feet of air at 72 inches of manifold pressure,
equivalent to 21 psi above ambient pressure. Seven intake trunks, 2.75 inches in diameter,
undulate forward from the supercharger housing to supply the compressed mixture to the intake
valves perched atop the forged aluminum heads. The pressure within each cylinder will
approach 235 psi before the four, low tension magnetos on the nose case supply the 1400
sparks per second, 20,000+ volts per spark, to the 56 individual spark plugs that fire off the
charge.
In that one second, almost 14 fluid ounces
of 115/145 performance number aviation
gasoline have been injected into the
gaping Bendix PR-100 carburetor with an
intake throat the size of a tool box. Five
fluid ounces of anti-detonant
water/methanol mixture have been forcefed
into the intake system to assure the
supercharged mixture, heated by
compression, does not exceed 194°F,
thereby moderating the charge to burn at
the proper rate and at a sub-solar
temperature. More than 12,408 BTU’s of
heat energy (3.1 million calories) have
been released into the engine, enough to
raise the temperature of a 55 gallon drum of water 27° F. Approximately 8.6 fluid ounces of
water has been sprayed at 35 psi from 14 nozzles placed in the narrow, 3.75 inch gap of the
cowling inlet to atomize the fluid and dissipate heat directly from the otherwise air-cooled
cylinders. In that thousand milliseconds, approximately 60 lbs of cooling air have entered
through the three square feet of inlet area (area of a pizza box), its temperature raised 45° F by
ram pressure alone, then cleverly guided by a tapered spinner afterbody, shrouds, hoods, and
baffles to flow across the four rows of seven cylinders, expand across the engine, absorb heat,
and exit the cowling exhaust chute.
In that one second, tucked inside the
forged aluminum R-4360 nose case, 10
hefty steel planet gears, an inch thick with
23 teeth each, caged in the propeller
reduction unit, have spun on their own plain
bearings 50 times and orbited inside the
ring gear close to 19 times to slow the
speed of the propeller relative to the
engine. The 13.5 foot diameter, four-bladed
Aeroproducts propeller and regulator, some
528 pounds altogether, have made 18.75
revolutions, the tips arcing through 795 feet
of linear distance and subjected to 2700
times the force of gravity. Each furnacebrazed,
hollow steel propeller blade has a chord (width) of 15 inches and sports a custom
contour at the outer trailing edge to reduce tip load vibration as it strains to efficiently convert
900 horsepower into thrust, speed, and victory.
In that one second, the 2 pressure oil pumps have sent 148 fluid ounces, almost 1.2 gallons, of
60 weight, W120 aviation oil at 90 psi through the engine to lubricate and cool the reciprocating
symphony, while seven scavenge pumps have collected the oil, circulated it through the dual oil
coolers, and back to 30 gallon oil tank. A lonely tablespoon of oil has escaped past the piston
rings, burned, and been blown overboard. Approximately 4.3 fluid ounces of spray bar water
have been ejected from 56 ports at 15 psi.; 14 pairs of diametrically opposed ports for each of
the two oil coolers, one cooler tucked into each wing root. The spray bar water is directed onto
metal tabs welded to the stainless steel spray bar tubing, fracturing the stream and turbulating
the mist, essential for removing 270 BTUs of heat per second from the oil.
In that one second, over 1.72 million, yes
million, foot/lbs of work have been done,
enough to raise a 150 lb. man 2.2 miles
into the air or lift a 60 ton Abrams battle
tank through a football goal post. The
mighty aircraft has covered 660 feet,
roughly 1.5% of the current 8.48 mile
Reno Unlimited course. Each second
approximately 2 lbs of fluids are
consumed and ejected, reducing the
racer’s 45 lbs per square foot takeoff wing
loading by 10% at touch down. In that
single second, coming off Pylon 6, g force
easing, wings almost level, the pilot
begins a quick scan of the 9, 2.5 inch
diameter analog gauges essential for racing (induction temperature, cylinder head temperature,
oil temperature, oil pressure, torque pressure, oil temperature, oil pressure, cylinder head
temperature, anti-detonant injection pressure, cylinder cooling spray pressure, fuel flow, oil
cooler spray bar pressure, spray bar pressure, oil cooler door position indicator) aligned across
the top 2 rows of the panel. The wide eyed but extremely focused pilot, Brian or Dennis
Sanders, dodging dust devils, scanning the sky for aircraft and the ground for their shadows, is
reassured to find all is well within the thundering juggernaut as it rat races over the mile high
desert outside Reno, Nevada.
In just one second of the 535 seconds it takes to complete the 66.9 mile race, man and
machine, wind and air, water and oil, speed and gravity, combine to make air racing the most
elite motorsport of all. Despite engines and airframes that haven’t been manufactured since
1960, Unlimited-class air racing remains the World’s Fastest Motor Sport, and an experience of
sight and sound unique in all of racing. Long live the big iron.
My thanks to Brian Sanders, Graham White, Pete Law, Bill Pearce, and Hewlett-Packard for
their expert and most welcome assistance. Tom Fey: 8-28-06
August 28, 2006
Story by Tom Fey
Photos by W J Pearce
At a race weight of 6.25 tons, the trick Pratt & Whitney R-4360-63 powered T.20 Sea Fury
“Dreadnought” is truly the big kid on the air racing block. Built, owned, and flown by the late
Frank and sons Brian and Dennis Sanders, this two-seat masterpiece has turned the pylons as
fast as 458.9 mph by virtue of the clean, highly detailed airframe and the 3,800 horses that tread
within her custom cowling. Dreadnought has won the National Championship Reno Air Races
twice, and finished second 13 times. To simply call this airplane large and fast, while certainly
accurate, diminishes the fantastic complexity required to attain such impressive performance. If
you could examine a single second of time while Dreadnought is hard at work, engine at 3000
rpm and 72 inches of manifold pressure, just 70 feet off the deck at 450 mph on the Reno
course, what would you find?
In that one second, the thundering, 4,290
lb R-4360 radial has gone through 50
revolutions, with each of the 28 finelyfinned
cylinders firing 25 times. Inside
each cylinder of 156 cubic inch (2.6L)
displacement (same as the entire V-6
powerplant in a C class Mercedes-Benz)
a piston the diameter of a coffee saucer
has transmitted close to140 horsepower
to the master rod. Seven cylinders are
linked to each master rod, with each of
the four master rods adding their own
900+ horsepower to the crankshaft.
Seven hundred power pulses, one pulse
for each 9.5° of propeller arc, have been transmitted to the six foot long, one-piece, four throw
steel crank. Each piston has traveled 50 feet in linear distance, changing direction 100 times per
second, with the total linear travel of all 28 pistons adding up to a ¼ mile. Each sodium-filled
exhaust valve the diameter of a beer can (2.5 inches) has required 2.1 tons of initial force to
open the port to expel the 1600° F gasses into the 14 exhaust stacks specifically choked to
maximize jet thrust from the exhaust. The single-stage supercharger rotor, 14 inches in
diameter, has spun 348 times, delivering 98 cubic feet of air at 72 inches of manifold pressure,
equivalent to 21 psi above ambient pressure. Seven intake trunks, 2.75 inches in diameter,
undulate forward from the supercharger housing to supply the compressed mixture to the intake
valves perched atop the forged aluminum heads. The pressure within each cylinder will
approach 235 psi before the four, low tension magnetos on the nose case supply the 1400
sparks per second, 20,000+ volts per spark, to the 56 individual spark plugs that fire off the
charge.
In that one second, almost 14 fluid ounces
of 115/145 performance number aviation
gasoline have been injected into the
gaping Bendix PR-100 carburetor with an
intake throat the size of a tool box. Five
fluid ounces of anti-detonant
water/methanol mixture have been forcefed
into the intake system to assure the
supercharged mixture, heated by
compression, does not exceed 194°F,
thereby moderating the charge to burn at
the proper rate and at a sub-solar
temperature. More than 12,408 BTU’s of
heat energy (3.1 million calories) have
been released into the engine, enough to
raise the temperature of a 55 gallon drum of water 27° F. Approximately 8.6 fluid ounces of
water has been sprayed at 35 psi from 14 nozzles placed in the narrow, 3.75 inch gap of the
cowling inlet to atomize the fluid and dissipate heat directly from the otherwise air-cooled
cylinders. In that thousand milliseconds, approximately 60 lbs of cooling air have entered
through the three square feet of inlet area (area of a pizza box), its temperature raised 45° F by
ram pressure alone, then cleverly guided by a tapered spinner afterbody, shrouds, hoods, and
baffles to flow across the four rows of seven cylinders, expand across the engine, absorb heat,
and exit the cowling exhaust chute.
In that one second, tucked inside the
forged aluminum R-4360 nose case, 10
hefty steel planet gears, an inch thick with
23 teeth each, caged in the propeller
reduction unit, have spun on their own plain
bearings 50 times and orbited inside the
ring gear close to 19 times to slow the
speed of the propeller relative to the
engine. The 13.5 foot diameter, four-bladed
Aeroproducts propeller and regulator, some
528 pounds altogether, have made 18.75
revolutions, the tips arcing through 795 feet
of linear distance and subjected to 2700
times the force of gravity. Each furnacebrazed,
hollow steel propeller blade has a chord (width) of 15 inches and sports a custom
contour at the outer trailing edge to reduce tip load vibration as it strains to efficiently convert
900 horsepower into thrust, speed, and victory.
In that one second, the 2 pressure oil pumps have sent 148 fluid ounces, almost 1.2 gallons, of
60 weight, W120 aviation oil at 90 psi through the engine to lubricate and cool the reciprocating
symphony, while seven scavenge pumps have collected the oil, circulated it through the dual oil
coolers, and back to 30 gallon oil tank. A lonely tablespoon of oil has escaped past the piston
rings, burned, and been blown overboard. Approximately 4.3 fluid ounces of spray bar water
have been ejected from 56 ports at 15 psi.; 14 pairs of diametrically opposed ports for each of
the two oil coolers, one cooler tucked into each wing root. The spray bar water is directed onto
metal tabs welded to the stainless steel spray bar tubing, fracturing the stream and turbulating
the mist, essential for removing 270 BTUs of heat per second from the oil.
In that one second, over 1.72 million, yes
million, foot/lbs of work have been done,
enough to raise a 150 lb. man 2.2 miles
into the air or lift a 60 ton Abrams battle
tank through a football goal post. The
mighty aircraft has covered 660 feet,
roughly 1.5% of the current 8.48 mile
Reno Unlimited course. Each second
approximately 2 lbs of fluids are
consumed and ejected, reducing the
racer’s 45 lbs per square foot takeoff wing
loading by 10% at touch down. In that
single second, coming off Pylon 6, g force
easing, wings almost level, the pilot
begins a quick scan of the 9, 2.5 inch
diameter analog gauges essential for racing (induction temperature, cylinder head temperature,
oil temperature, oil pressure, torque pressure, oil temperature, oil pressure, cylinder head
temperature, anti-detonant injection pressure, cylinder cooling spray pressure, fuel flow, oil
cooler spray bar pressure, spray bar pressure, oil cooler door position indicator) aligned across
the top 2 rows of the panel. The wide eyed but extremely focused pilot, Brian or Dennis
Sanders, dodging dust devils, scanning the sky for aircraft and the ground for their shadows, is
reassured to find all is well within the thundering juggernaut as it rat races over the mile high
desert outside Reno, Nevada.
In just one second of the 535 seconds it takes to complete the 66.9 mile race, man and
machine, wind and air, water and oil, speed and gravity, combine to make air racing the most
elite motorsport of all. Despite engines and airframes that haven’t been manufactured since
1960, Unlimited-class air racing remains the World’s Fastest Motor Sport, and an experience of
sight and sound unique in all of racing. Long live the big iron.
My thanks to Brian Sanders, Graham White, Pete Law, Bill Pearce, and Hewlett-Packard for
their expert and most welcome assistance. Tom Fey: 8-28-06
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