Going Green in Aerospace

Although it seems like the ‘going green’ movement has been around for awhile now there has been a relatively new push for the aerospace industry to become more ‘green’. In case you’ve been isolated from civilization and haven’t heard, the ‘green’ movement is all about making making things more efficient and more environmentally friendly by reducing, reusing, and recycling.

While working as a Co-op at Gulfstream Aerospace Corporation, I was able to experience first hand some of the ways Gulfstream has made it a priority to become a ‘greener’ company. First things first, a little background about the company. Gulfstream is a relatively small company in the aerospace industry(compared to Boeing or Airbus) that builds luxury business jets. However Gulfstream has been growing rapidly over the last decade and has taken steps to insure that they will be as efficient and as ‘green’ as possible when building airplanes.

Green Manufacturing

Before we can talk about the jets themselves we have to look at how they’re built. Building an airplane takes a whole lot of Aluminum that has to be cut down, drilled, riveted, sealed, etc. From my experience on the manufacturing floor at Gulfstream, just from one day of work there is a tremendous amount of scrap metal and aluminum shavings on the ground. Since the scraps can no longer be used  they were thrown away, however Gulfstream found that they could drastically cut down on their waste by collecting all of the excess aluminum and melting it back down to be reused. The first step for the aerospace industry to become more green is to start with the manufacturing processes. Another green initiative that Gulfstream and other aerospace companies have reduced their use of toxic chemicals by substituting them with less toxic materials in order to reduce their environmental impact.

Biofuels

As far as the airplanes themselves go, the Federal Aviation Administration (FAA) has in place an environmental policy with rules and regulations that all aircraft must pass before receiving certification. One of the main FAA requirements is for the aircraft engine emissions to be below a certain level (depending on the type of aircraft) The engine emissions have the most environmental impact by far. To combat this fact, one of the new developments, that is in the process of being tested and certified now, is the use of biofuels as aircraft propellant to reduce emissions and fuel consumption of the engines. Aviation biofuel is considered the main way the aerospace industry can reduce it’s carbon footprint. Currently the aerospace industry is responsible for 2 percent of all emissions. This is a huge number, however studies suggest that with the widespread use of biofuels as propellant the engine emissions of aircraft could be reduced by 80 percent or more. Biofuels would be the main way for the aerospace industry to become more 'green'. Since 2008 there have been flights using everything from vegetable cooking oil to alge as used as fuel to demonstrate the potential of biofuels. Some challenges that still need to be overcome before biofuels are fully implemented are cold weather storage and engine compatibility. One problem that has been discovered is that, at cold temperatures, biofuels tend to oxidize which causes them to become gel like and unusable. Another problem is it's use in engines can cause rubber hoses and seals to shrink which can cause problems in flight.

Green Design

Furthermore, their are new 'green' designs that have been used and that are being developed in order to build more efficient airplanes. One of the most widely used designs that is used on most modern commercial aircraft such as the Boeing 737 and Airbus 320 (the most widely used commercial jets in the world) are the use of winglets (See Photo). Although winglets come in various shapes and sizes, they all serve the same purpose, which is to decrease the induced drag of the aircraft caused by wing tip vortices. Reducing the induced drag of the aircraft (which can account for as much as 50 percent of the total aircraft drag) will improve the performance of the aircraft by reducing fuel consumption (usually around 10%). This is caused by the less engine power that is required to overcome the  drag. Obviously reduced fuel consumption leads to a more efficient and 'greener' aircraft. Recently there have been new winglet designs being tested such as spiroid winglets which have been shown to reduce the induce drag of the aircraft even further. NASA along with other companies and universities have done extensive research to develop what they think will be the future of aircraft based on the future environmental compatibility as well as energy efficiency requirements. Many of the design proposals included lifting bodies, high bypass ratio engines, high aspect ratio wings, and rear mounted engines.

Overall the future of aerospace looks promising and exciting as companies develop more and more ways to increase the efficiency of their aircraft. In all likely hood the next generation of aircraft will look like nothing we're used to seeing. Pictured on the right is a concept plane developed by MIT which features 3 rear mounted high bi-pass ratio engines and a lifting body. Some of the designs are even further out of the box. I am excited to see what companies come up with as the next generation of 'green' aircraft become the standard for comercial aerospace.

New Technologies in Aerospace

Supersonic Cruise

The Aerospace industry is an exciting industry that is constantly changing and is constantly using cutting edge technology to push the boundaries of our imaginations of what is possible. Besides the 'green' movement that I've previously talked about, a lot of aerospace companies are looking at efficient supersonic cruise as the future of the industry. One of the frustrating things about air travel is the time it takes for transatlantic flights, supersonic cruise would shorten the time it takes considerably by cruising at speeds of around mach 2 (typical comercial flights fly around mach 0.8). If you're interested in aerospace you've probably heard of the Concorde, which was a comercial supersonic jet that flew in the 70's till 2003. However the Concorde was retired due to noise issues (sonic boom created at supersonic speeds) as well as poor fuel consumption and small capacity which lead to very high ticket prices.

while working at Gulfstream I got to learn about one of the ways they are tackling the noise problem of supersonic flight. Since the FAA requires a certain noise level in decibels at take-off/landing as well as fly by in order to land at airports in more populous areas, it is crucial for future supersonic cruise aircraft to be quiet. One of the technologies that Gulfstream was developing in conjunction with NASA is the Quiet Spike. The Quiet Spike is basically a big, retractable spike that sticks off the nose of the aircraft (as shown) which causes 3 shock waves to develop on the spike that travel parallel to each other as supersonic speeds are approached. This creates a smaller, more quiet boom as opposed to the loud boom that occurs from shock waves forming on the nose and wings of a typical supersonic aircraft.

Avionics and Fly-by-Wire

As the rest of the world has become more and more computer centered the same has happened in the aerospace industry. One of the coolest projects I had the opportunity to work on at Gulfstream was preforming usablility testing on the G650 iPod Cabin Management System application. Basically the Gulfstream Cabin Management System (GCMS) provides the passenger with digital control of cabin systems through touch screens, capacitive touch switches and Passenger Control Units. Using an iPod touch that is synched to a particular seat on the aircraft, passengers can control the lighting, temperature, speakers, monitors, entertainment equipment, window shades, CabinView system and call the flight attendant. What I was responsible was for running tests on the system, needless to say I had a good time 'testing' the technology in my office (pictured left), a 60 million dollar business jet. The GCMS is just one example of how aerospace companies are implementing more advanced technology into their fleet.

Another project I got to work on at Gulfstream was the implementation of touch screen controllers (TSC's) in the cockpit to replace the traditional manual instruments and switches. What this project entailed was preforming pilot testing of the TSC's in simulated flights to insure that the touch screens could still be operated effectively in various conditions such as turbulence. Pictured is the cockpit of a Gulstream G650, as you can tell there a quite a few screens and even more overhead that you can't see. In the future we will start to see more and more companies implementing more and more advanced technology into the cockpits of their aircraft.

One last big change that we will see in future aircraft is the use of fly by wire (FBW) systems to control the aircraft. FBW is a system that replaces the conventional manual flight controls of an aircraft with electronic controls. The movements of flight controls are converted to electronic signals and transmitted by wires to control the actuators at each control surface. This is different than the manual controls where the flight controls are physically connected to each control surface. One of the main advantages of FBW is that the Flight Control Computer (FCC) can automatically adjust to the flight condition and help stabilize the aircraft without the input of the pilot. This is a huge technological advancement for the aerospace industry that increases the safety of the aircraft. Companies such as Gulfstream and Boeing have already started implementing FBW systems into their new aircraft.