Rutan Defiant: A True defiant
This is the Rutan Defiant, a remarkable testament to innovation and
design ingenuity. Conceived by Burt Rutan, a visionary in aircraft design, the Rutan Defiant
stands out with its distinctive configuration and pioneering spirit. This aircraft, with its canard
front wing and push-pull twin-engine setup, challenged conventional aviation norms and opened
new avenues in aircraft efficiency and safety. The Rutan Defiant not only represents a unique
chapter in aviation history but also embodies the relentless pursuit of aerodynamic excellence
and the spirit of experimental aviation. Today, we delve into the story of the Rutan
Defiant, exploring its design philosophy, technical advancements, and the enduring
legacy it leaves in the world of aviation." Whenever people spot this plane, they're
immediately struck with the question, “Why does it look so extraordinary?” It's
not just its appearance that's arresting; it's the masterful engineering behind it. The aim
was bold and clear: to craft an aircraft that sets new standards. The brilliant stroke? Positioning
the engines in an unconventional arrangement, creating the Defiant's unique, asymmetrical
design. A true marvel, it dazzles both in its visual impact and technological innovation.
In the 1970s and 80s, Burt Rutan experienced a highly productive phase in his career,
developing numerous innovative, fast, and high-performance models for homebuilt
aircraft. He led the way in devising a new method of construction that utilized molded foam
and fiberglass, bypassing the need for traditional molds and creating sleeker airplane designs.
Rutan founded Scaled Composites with the objective of pushing the boundaries in aircraft design for
commercial and defense clients. Prior to this, at Rutan Aircraft Factory, he designed
the groundbreaking Voyager. This aircraft earned a place in history as the first to fly
around the world non-stop without refueling. In the early 1990s, Rutan set his sights
on creating an aircraft that would not sacrifice safety or efficiency, continuing
his legacy of innovation in aviation design. Enter the Rutan Defiant, a twin-engine aircraft
with canard control and centerline thrust. As a proof-of-concept, this four-seater "push-pull"
engine aircraft, featuring a unique design, evolved from the insights gained from the smaller
VariEze. It maintained the rear-positioned, swept-back wings with winglets, a canard
foreplane, and a combination of retractable nosewheel and fixed main-wheel landing gear.
To appreciate the innovative nature of the Defiant, one must consider the prevailing aircraft
design standards of the era. Twin-engine aircraft, largely unchanged since the 1930s,
typically featured an engine on each wing, with a symmetric airframe on both sides
of the aircraft's centerline. The main advantage of this design was its redundant
systems for safety; if one engine failed, the other could continue to power the aircraft,
a critical feature for over-water flights where engine failure would pose significant risks.
The standard twin-engine configuration is not without its drawbacks. Should one engine of
a conventional twin fail, the aircraft faces challenges not just from the loss of power, but
from uneven thrust. The farther the engines are placed from the aircraft's center, the more severe
the effect of this asymmetrical thrust becomes. To combat the issue of uneven thrust and the
problems related to the 'critical engine,' some aircraft designers have turned to a
'centerline thrust' configuration, aligning one engine in front and another at the rear in a
push-pull setup. This arrangement centralizes the thrust line, but it introduces other problems; the
noise level inside the cabin can be significantly higher, and vibrations can be more pronounced
compared to conventional twin-engine designs. The Cessna Skymaster exemplifies this push-pull
design, yet it falls short in terms of efficiency because of several design shortcomings.
The cabin of the Skymaster is notorious for its loud and vibratory environment.
Back the Defiant, Burt Rutan’s design utilized a canard on the nose for pitch control,
winglets and a retractable nosegear with fixed, slickly faired mains. Typically, the Defiant
realized economies of design not possible on normal twins. The airframe had a wetted
area only 56 percent that of normal twins, and the winglets offer 30 percent less
induced drag by increasing the effective span. The debut of the prototype airplane sparked
significant excitement in the general aviation sector, particularly as Rutan revealed
his intention to seek certification for the Defiant for mass production. Breaking new
ground beyond his earlier single-engine models, Rutan equipped the Defiant with two 160-hp
O-320 Lycoming engines, a design choice aimed at preventing asymmetric thrust problems.
While pilots found the Skymaster to be a manageable twin-engine aircraft, it was plagued
by various issues that led to its downfall. Rutan, prioritizing safety above all, managed to
circumvent these issues, making the Defiant an almost foolproof twin-engine aircraft. In line
with the canard designs that came before it, the Defiant was built with a strong emphasis
on the safety and wellbeing of its passengers. Rutan spared no effort in designing the Defiant,
creating an aircraft that skillfully avoided the common pitfalls associated with operating
twin-engine planes on a single engine. The aircraft, designed with a singular focus on
performance and efficiency, boasts a configuration that accommodates a crew of one pilot and has
the capacity to carry 3 passengers. It measures an impressive 22 feet 10 inches in length, which
is complemented by a wingspan of 30 feet 9 inches, standing at a height of 9.33 feet.
The wing area is expansively designed, covering 139.4 square feet, which plays a crucial
role in its lift and stability. When it comes to weight, the aircraft is relatively light with
an empty weight of 1,701 pounds. However, it can support a gross weight of nearly 3000
pounds, this translates to a useful load of nearly thirteen hundred pounds, which is
not particularly below industry ideal. In terms of fuel capacity, the aircraft
is able to hold up to 120 gallons of fuel, to feed the two Lycoming O-320 engines,
each capable of delivering 160 horsepower. In terms of performance, the aircraft excels with
a maximum speed of 188 knots and a comfortable cruise speed of 167 knots. Its range is equally
notable at 1000 nautical miles. The service ceiling of the aircraft reaches up to 18,000
feet with a rate of climb of 1,600 feet/min. Regarding its capability for long-distance
cruising, the Defiant stood out impressively, fuel consumption rate is just 15 gallons per
hour at 65 percent power, it enabled a pilot and passengers to effortlessly journey 1000 nautical
miles without the need for refueling. However, efficiency was just one of the many strengths of
the Defiant. True to Rutan's design philosophy, the foremost emphasis in the Defiant's design was
on safety, and it was evident that Burt Rutan had succeeded in creating an exceptionally
easy-to-handle twin-engine aircraft. The Defiant displayed several unique flying
characteristics that set it apart from other twin-engine planes. It had an innate affinity
for flight, maintaining its speed and altitude with a remarkable reluctance even when
power was cut. One of the most notable features was its virtually non-existent stall
tendency, allowing the pilot to fully pull back on the stick without significant risk. This
characteristic significantly enhanced safety, as it meant that even in the event of an engine
failure, the pilot of the Defiant had a higher margin for error and a better chance of returning
safely, both for the aircraft and for themselves. The interior design of the cabin offered
comfort for both the pilot and passengers, ensuring a pleasant journey for all on board. The
control panel was notably roomy and expansive, providing ample space for the installation of a
wide range of avionics equipment. However, there was a minor limitation in terms of installing
radar equipment, as the wing's narrow design did not allow for the accommodation of a dish antenna.
In addition to its comfortable cabin and versatile panel, the Defiant boasted impressive altitude
capabilities. Demonstrating this, Burt Rutan's brother, Dick, once piloted the aircraft to
heights exceeding 25,000 feet. Remarkably, all of these high-altitude feats were
achieved with an engine system that was carbureted and normally aspirated, rather
than being fuel-injected and turbocharged. When both engines of the Defiant were functioning
normally, the aircraft exhibited a prompt response to throttle input during takeoff. However, it
wasn't particularly suited for short runways. The Defiant didn't cling to the ground
excessively, but it wasn't designed as a Short Takeoff and Landing aircraft either.
Once airborne and cruising at a stable 100 knots with the nose gear tucked in, the Defiant
ascended as if propelled by a powerful force. One of the remarkable aspects of flying
the Defiant was that, for the most part, it could be operated as if it were a single-engine
aircraft, smoothly controlling both throttles simultaneously, regardless of whether one or both
engines were active. In single-engine mode, the aircraft was exceptionally tolerant and easy to
handle. Nevertheless, attempting a single-engine takeoff, especially under conditions like Mojave's
3000-foot pressure altitude, was not advisable. This issue of single-engine operation had been
a significant challenge for the Skymaster, as Cessna discovered. Some pilots, not realizing
the rear engine had stopped during taxi or run-up, attempted to take off using only
the front engine. To address this, Cessna implemented a procedure where the rear
throttle was advanced first during takeoff, followed by the front throttle, ensuring
a safer and more controlled ascent. In a single-engine go-around, a pilot simply
needs to fully advance the throttles and pull back on the control stick to maintain flight.
The Rutan Defiant, like the Cessna Skymaster, performs slightly better with only the rear
engine active than with just the front engine. Under normal conditions, the rear engine can
achieve around 300 to 350 feet per minute climb, compared to the front engine's 250 to 300 fpm.
This difference, offset by differently pitched propellers, results from reduced fuselage drag and
less turbulent air affecting the rear propeller when the front engine is not in operation.
The Rutan Defiant stands out from conventional designs, appealing to pilots seeking uniqueness.
However, building a Defiant requires significant investment in time and money, beyond the
reach of many. For those who can afford it, the Defiant presents a forward-thinking design,
offering advanced performance and safety. Despite its promise, the Defiant faced challenges. The
high costs of certifying such a novel design deterred potential investors, relegating the
prototype to being just Burt Rutan's personal aircraft. This outcome is particularly regrettable
considering the Defiant's advancements in safety, performance, and efficiency. Its
pioneering nature may have been too advanced for its time. Of the 200 plan sets
sold, around 20 kits were actually constructed, with nine known to be in operation by mid-1987
and nineteen registered with the FAA in 2005. In conclusion, the Rutan Defiant, a true
defiant in the realm of aviation, represents an extraordinary blend of innovative design,
aerodynamic efficiency, and safety, pioneering a unique approach in aircraft engineering that,
despite its limited production, leaves a lasting impact on the principles of aircraft design
and the pursuit of aerodynamic excellence.
