Boeing teaches us not only how planes fly like an eagle horizontally, but also how they takeoff like a rocket vertically! A Boeing 787-9 Dreamliner performed a near “S-vertical” takeoff, on Friday, June 12, 2015, as Boeing and Vietnam Airlines crew teamed up to put the airliner through its paces over Moses Lake, Washington.
This test run was completed in preparation for its performance at the 51st International Paris Air Show, held June 15-21, 2015 at Le Bourget Exhibition Centre a few kilometers from Paris.
Spectacular pictures and Boeing video released Friday exhibit the groundbreaking Boeing 787-9 airliner’s state-of-the-art digital “glass cockpit” aviation, navigation, and communication systems, alongside its “rocket science” maneuvers.
It appears the jet is heading straight up, like a rocket, so we aim to discuss in this article, the scientific and technological anatomy of a Boeing 787-9 Dreamliner, as it performs a near vertical takeoff for the benefit of laypersons watching this stunning video below.
In other words, consider this piece an easy-to-read primer breakdown for laypersons to understand how a commercial aircraft takes off like a rocket! In anticipation of the 2015 Paris Air Show, this brief primer is “jet propulsion and rocket science for laypersons!”
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Boeing says the above company video “spotlights technical maneuvers that showcase some of the airplane’s many capabilities.”
In all fairness to the Boeing-Airbus global commercial aircraft manufacturing competition, Friday’s near vertical takeoff performance of the Boeing 787-9 Dreamliner is not the first one by a large commercial airliner of this jumbo size class. The video below is an equally remarkable “S-vertical” takeoff performance of an Airbus A380 at the 2013 Paris Air Show.
Two French Navy pilots teamed up with Airbus to display a stunning near vertical takeoff and near vertical flight maneuver at the 2013 Paris Air Show on empty fuel tanks and extremely light weight, mainly because the Airbus A380 had previously performed a short maneuver presentation nearby the Le Bourget Exhibition Centre outside of Paris.
CNN prompted Boeing to “share specifics about the takeoff and banking angles during the flight.” A company spokeswoman told CNN “we unfortunately aren’t sharing specifics about the profile such as bank angles at this time.”
“Some of what you’re seeing on takeoff is a trick of perspective,” said Boeing 767 pilot Patrick Smith, who blogs on aviation at AskthePilot.com. “It looks like the takeoff is at a near vertical 90 degree angle — trust me it’s not.”
“A 20 degree pitch-up on takeoff is pretty strong,” said Smith, describing what passengers inside the cabin may feel during takeoff.
What a competitively strategic “marketing bonanza move” for the American airplane manufacturer to enhance the Boeing 787 Dreamliner brand after its dubious market launch a few years back.
That news is ancient history now after Friday’s remarkable takeoff of the Boeing 787-9, spiraling up as a viral technological phenomenon across social media.
As of May 2015, 509 Boeing 787-9 Dreamliner aircraft (amounting to 46 percent of all 787 orders) have been ordered by 30 airlines around the world.
Smith further comments on the video: “If they’re pushing the envelope and having fun, they might be going a bit past what the command bars are showing, but just temporarily — again, it’s the Paris Air Show!”
Friday’s trial run of a Boeing 787-9 Dreamliner, undergoing a near “S-vertical takeoff” to be performed at the 2015 Paris Air Show, further highlights the company’s technologically innovative capabilities in aviation safety and critical flight performance. Remarkably displayed are critical flight maneuvers at subsonic flight envelop extremes akin to a “military fighter.” Most of all, what is displayed is a more extraordinary extreme takeoff requirement of the Boeing 787-9 Dreamliner performing nearly as a “vertical rocket” propulsive system.
It is this latter extraordinary extreme, where it appears the jet is heading straight up, like a rocket, that we wish to discuss in the next section, the simple scientific and technological anatomy of a Boeing 787-9 Dreamliner near vertical takeoff for the benefit of laypersons looking at the stunning pictures.
Anatomy of a Boeing 787-9 “S-Vertical” Takeoff
“Presumably the plane was very light because it wasn’t carrying any passengers, probably had a very light fuel load, no freight, so it would have been able to perform a steeper than normal ascent — but not to the extent the video seems to show,” Boeing 767 pilot Patrick Smith said.
“But for demonstration purposes, under lightweight conditions, it’s perfectly natural for this airplane to do that. It’s nothing dangerous.”
A Boeing 787-9 Dreamliner without its payload and fuel weighs about 117,617 kilograms (or 259,301 pounds) equal to about 29 elephants. The maximum payload takeoff weight is designed for 227,930 kilograms (or 502,500 pounds). The airliner’s wing span is 197 feet (or 60 meters), the aircraft’s length is 186 feet (or 57 meters), and the air vehicle’s height is 56 feet (or 17 meters).
The commercial airliner is designed to fly subsonically at Mach 0.85 (relative to the speed of sound), that is, about 650 miles per hour.
Forward thrust of a Boeing 787-9 Dreamliner at horizontally level flight is “rearward ejection of air flow” through a high-intake engine (taking in a ton of air per second) mounted on the wings with the condition that the air flow in the engine exhaust jet (creating the thrust) originates from the airliner’s forward flight design speed (topping at Mach 0.85).
Essentially, the two air-breathing turbofan propulsion systems of the Boeing 787-9 Dreamliner, operating at level flight, are fundamentally converging-diverging flow stream nozzles with a sonic plenum of combustible heat input in the middle, wherein fuel-air mixture propellant is burned (in other words, these turbofans are basically horizontally-directed “ideal” rocket motors, sort-of-speak, attached to wings). The exhaust jet is a characteristic velocity dependent on how well the flow stream (calculated using advanced three-dimensional computational fluid dynamics) through the engine device is designed.
As the Vietnam Airlines crew kept close tabs on the climb rate, airliner vehicle speed, and “glass cockpit” command bars, the near “S-vertical” takeoff momentarily shifts the Boeing 787-9 in an aggressive flight takeoff performance mode akin to a rocket propulsive system.
Fluidic momentum suggests the near vertical thrust needed to achieve the rapid climb equals a large air intake mass flow through the engines multiplied by an even larger engines’ exhaust jet velocity, due to the high vehicle speed of the Boeing 787-9 vertically upward, as seen on the company video.
Hence, the near vertical thrust readings on the “glass cockpit” command bar of the Boeing 787-9 airliner is essentially a non-dimensional ratio of two characteristic velocities — one, which is an exhaust jet dependent on how well the engine flow stream is designed, over another, which is a characteristic velocity about 40 percent higher than the speed of sound inside the combustion chambers of the engines.
This near vertical thrust is one measure of performance of the Boeing 787-9 near “S-vertical” takeoff, as seen on the company video.
Another consideration is how effectively or usefully do the engines burn fuel. This requires next-generation engines, having a sufficiently large overall pressure ratio, so as to have sonic flow at the throat of the engine flow stream design.
It is useful here to consider three additional figures of merit — fuel burn (or specific fuel consumption), specific impulse, and engine thermal efficiency — in terms of various Boeing 787-9 vehicle parameters from the perspectives of the Boeing aircraft design and the General Electric GEnx-1B and/or Rolls-Royce Trent 1000 engine designs adopted.
Both of these adopted engines “represent nearly a two-generation jump in propulsion technology used on the Boeing 767,” whereby the Boeing 787-9 Dreamliner uses 20 percent less fuel than any other airplane of its size, according to Boeing (see Appendix on the 787 Dreamliner Facts below).
Back in 2002, Boeing foresaw increased market demand for its Boeing 767 class twin-aisle airplane flying over significantly larger range. The company believed the airline industry was evolving from a “hub-and-spoke” to a “point-to-point” lower-fuel cost operational model.
The Boeing 787 Dreamliner is an outgrowth of the challenge to meet this airline industry demand for making significant advances in overall airplane design requiring greater advances in propulsion system innovation.
Boeing Commercial Airplane alongside General Electric and Rolls-Royce aircraft engine manufacturers approached this challenge by “improving fuel burn (that is, “specific fuel consumption” and/or “specific impulse”) of the Boeing 787 Dreamliner engines in three traditional performance areas,” according to the aircraft manufacturer:
- Higher propulsive efficiency through increased bypass ratio (which measures a ratio of the engine front fan diameter to the engine core diameter, see Appendix for looks inside the 787 Dreamliner ultra-high bypass ratio aircraft engines). [Note: an engine’s propulsive efficiency = 1 / [ 1 + 0.25 (Cd)(Aw / Ain) ], wherein Cd is the drag coefficient of the airliner, Aw is the airliner’s wing area, and Ain is the air flow area at the aircraft engine inlet). Thus, monitoring increases in the propulsive efficiency unites the Boeing aeronautical engineer (Cd) and Boeing structural engineer (Aw) with the General Electric and Rolls-Royce propulsion engineer (Ain)].
- Higher engine thermal efficiency through increased overall pressure ratio and improved component efficiencies, exclusively involves the General Electric and Rolls-Royce propulsion engineer. [Note: an engine’s thermal efficiency measures a ratio of the increase in kinetic energy through the engine to heat input into the engine from fuel burn. The increase in kinetic energy through the engine is a half of the difference between the engine exhaust jet velocity squared and the aircraft’s forward velocity squared].
- Improved thrust-to-weight ratio through the application of advanced materials, brings together the Boeing structural engineer (weight, advanced materials, wing-tail-section-fuselage lift-to-drag ratios) and Boeing aeronautical engineer (thrust-to-weight) with the General Electric and Rolls-Royce propulsion engineer (thrust).
According to Boeing, the following facts are the conditions for the Boeing 787-9 Dreamliner’s near vertical takeoff using either General Electric GEnx-1B or Rolls-Royce Trent 1000 engines: Bypass ratio = 10; Fan diameter = 111-112 inches; Overall pressure ratio = 50; Thrust = 53,000-74,000 pound-feet; Specific fuel consumption (SFC) = 15% lower than the Boeing 767 class engines.
To achieve the near “S-vertical” takeoff mode, the propulsion engines must generate momentarily an enormous amount of near vertical thrust. The amount of fuel needed to produce such thrust must momentarily balance the weight of the Boeing 787-9 airliner. Hence, General Electric and Rolls-Royce propulsion engineers must consider a figure of merit, called specific fuel consumption (SFC), to characterize the engine’s fuel efficiency.
Specific fuel consumption (SFC) measures “how much fuel the engine burns each hour,” normalized by mass or weight, or in this case, “per pound (Newton) of thrust.” In other words, specific fuel consumption is the mass of fuel burned by the Boeing 787-9 engines in one hour divided by the thrust that the engine produces.
Putting this another way, by definition, specific fuel consumption is a ratio of the engine fuel mass flow rate to the amount of thrust produced during fuel burn. When we normalize this ratio by the engine air mass flow rate, we obtain another form of specific fuel consumption (which measures fuel burn efficiency) in terms of a ratio defining the fuel-to-air mix to the specific thrust (that is, the engine thrust normalized by the air mass or weight through the engine device).
The units of specific fuel consumption are mass per unit time divided by thrust force (in English units, pounds mass per hour per pound; in metric units, kilograms per hour per Newton).
Research experts and officials at NASA Glenn Research Center in Cleveland, Ohio, working from the standpoint of producing clean efficient turbofan engines, consider figure of merit tradeoffs between specific fuel consumption (SFC) versus nitrogen oxide (NOx) emissions. The key source of NOx emissions is the combustion of fuels inside the burner chamber of the aircraft engine device. This brings into consideration the multidisciplinary science of aero-environmental propulsion engineering.
However, we can also define another figure of merit, called the specific impulse, as directly related to the overall efficiency of the engines of the Boeing 787-9 Dreamliner in performing the near “S-vertical” takeoff. The specific impulse in performing this takeoff is a ratio of the near vertical thrust divided by the temporal rate of change of the Boeing 787-9 weight.
Naturally, of course, we do also have equilibrated lift-to-drag force ratios of the wings, tail section, and fuselage. However, such resultant equilibrated lift-to-drag forces are momentarily vectorially-directed at sharply inclined angles relative to the Boeing 787-9 airliner’s center of mass, as the near “S-vertical” takeoff flight maneuver of the airliner is being performed.
The overall (propulsion system) efficiency may be approximated as a product of the propulsive efficiency and the thermal efficiency. (Note: an engine’s overall efficiency measures a ratio of the engine’s thrust power (or “useful propulsive work”) to available fuel burn energy).
When we take the Boeing 787-9 near vertical takeoff speed, Uo, multiplied by the specific impulse, Isp, we get a measure of the engines’ thrust power. The available fuel burn energy is a ratio of the heating value of the fuel, H, to the gravitational constant, g.
Thus, the overall efficiency, Neff, of the Boeing 787-9 Dreamliner, performing as a near vertical takeoff rocket propulsive system, is Neff = (Uo)(Isp) / (H/g).
In summary, these seven (7) performance figures of merit — (1) fuel burn energy,(H/g), (2) specific fuel consumption, SFC, (which measures engine fuel burn efficiency), (3) specific impulse, Isp, (4) engine thermal efficiency, (5) overall (propulsion system) efficiency, Neff, (which is highly dependent upon the closely-monitored airliner’s takeoff flight speed and near vertical flight speed, Uo), (6) engine thrust power, (Uo)(Isp), and (7) nitrogen oxide (NOx) emissions (for aero-environmental propulsion engineering design considerations) — are altogether central to the Boeing 787-9 aviation achievements exhibited at the 2015 Paris Air Show on June 15-21, 2015 at Le Bourget Exhibition Centre outside of Paris. This article serves to describe for laypersons what really matters most in the anatomy of a near “S-vertical” takeoff of a Boeing 787-9 Dreamliner.
APPENDIX: Boeing 787-9 Dreamliner Facts
First flown in December of 2009, the Boeing 787 Dreamliner is the company’s “technological marvel” designed by hundreds of aeronautical, structural and propulsion engineers, invoking a concept called “virtual manufacturing” pulling together the aircraft’s design and manufacturing from around the world.
The Boeing 787 Dreamliner is also an aviation innovation in how it uses advanced technology, according to the company,
- to improve the cabin experience (including a “High-Efficiency Particulate Air” (HEPA) filter to “remove bacteria and viruses, and additional gaseous filtration system also removes odors, irritants and gaseous contaminants, some of the primary contributors to throat, eye and nose irritation”);
- to enhance the cabin eco-friendliness (which implements “scalloped chevrons on the engine casings to lower noise both inside and outside the cabin, making the airplane quieter for passengers, ground crews and communities”);
- to fully incorporate advanced lightweight carbon-fiber materials throughout the aircraft’s structural configuration (that is, “composite materials make up 50 per cent of the primary structure of the 787, including the wings and fuselage”), which for the composite fuselage allows higher cabin pressures that contributes considerably to passenger comfort;
- to fully integrate state-of-the-art digital “glass cockpit” avionics and navigation and advanced computerized communication systems located throughout the airframe (including “Smoother Ride Technology,” a Boeing-designed system that “senses turbulence and commands wing control to smoothen the ride in moderate turbulence, so that passengers enjoy a more comfortable flight, including reduced motion sickness”).
The Boeing 787-9 is powered by new high-bypass ratio engines from General Electric’s GEnx-1B, which
- Leverage the highly successful GE90 composite cold-stream front fan blades with the latest swept aerodynamics;
- Incorporate an entirely new composite fan case for significant weight savings;
- Incorporate state-of-the-art titanium aluminide (Ti-Al) blades in the last two stages of the seven-stage low pressure turbine. Hot turbine blades made of titanium aluminide (Ti-Al) material achieves significant weight savings over traditional nickel alloy turbine blades.
and Rolls-Royce’s Trent 1000, which
- Incorporate the latest swept aerodynamic cold-stream hollow-fan-blade technology evolved from the predecessor Trent 900 engine;
- Utilize the proven benefit of the Trent three-spool engine architecture. In the case of the Trent 1000, the three-spool design affords intermediate pressure power off-take with demonstrated benefits in engine operability and fuel consumption;
- Design the Trent 1000 with the latest computational fluid dynamics-enabled 3D aerodynamics for high efficiency and low noise.
The latest Boeing 787-9, which is longer with a farther range than its predecessor Boeing 787-8, first rolled off the assembly line in Everett, Washington, in 2013. Its first customer, New Zealand Airlines, received its order the next year. The new Boeing 787-10 commercial launch is anticipated in 2018.
Photo and Video Credits: The Boeing Company, General Electric Aircraft Engines, Rolls-Royce Aircraft Engines
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