OMEGA’S contributions
As a Solar Impulse Main Partner, OMEGA has not only invested in the project but has made a number of critical contributions to Solar Impulse in the area of engineering technology.
The performance simulation and testing system (test bench)
In 2007 the Solar Impulse team and OMEGA announced the development of a performance simulation and testing system (a test bench) for the project. The electromechanical system enables the SI development team to simulate and test all electrical systems at the conceptual stage (before production begins). Test results determine the effective energy delivered by the solar cells to the motors and the performance of the motor, both under normal conditions and at temperatures ranging from -40°C to +55+C. They also measure battery capacity and the performance of the airplane’s controls.
A unique aircraft creates unique challenges
The creation of a plane like Solar Impulse creates some unique challenges. Designed to circumnavigate the globe powered only by the sun, the final aircraft, as well as its prototype, will be exploring unknown areas of flight because of their disproportionate size and weight.
Enormous wingspan, improbably low weight
The prototype has a wingspan of 63 metres and a weight of 1700 kilograms. Compare this with the Airbus A340 which has about the same wingspan but a takeoff weight which is roughly 200 times greater.
Because of its enormous wingspan and relatively short fuselage, Solar Impulse has low lateral (side-to-side) and directional stability. Its direction of flight can vary significantly from the direction of the fuselage. What’s more, the aircraft is sensitive to crosswinds on the approach because of its slow speed – about 55 kilometres per hour.
The OMEGA Instrument: indicating flight path and lateral drift
Considering these elements led astronaut and Swiss aeronautics legend Claude Nicollier to design the OMEGA Instrument, consisting of light bars which indicate the true heading (flight path) or lateral drift on a horizontal scale of light bars and on two vertical scales, the angle of the wing.
The light bars are very accurate, react instantly, and can be read easily by the pilot who can easily make necessary adjustments. The nature of Solar Impulse and its unique intended mission, however, made it necessary to add some features which contribute to the pilot’s safety.
Vibrating sleeves: alerting distracted or fatigued pilots
Although the OMEGA Instrument is extremely pilot friendly and easy to read, it is possible that the pilot, absorbed by his other tasks, will not notice the lights. The pilots will ultimately be flying in shifts of several days, which will require that they sleep while the plane is in the air and will also risk the fatigue associated with long flights.
Accordingly, there are vibrating alarm devices in the pilot’s flight suit sleeves which react as soon as the normal values are exceeded. For example, if the wing is inclined too far to the right, a vibration in the right sleeve will indicate that the pilot must correct the inclination of the wing to the left.
The vibrating sleeves were developed by OMEGA’s engineers to meet several parameters. They perform flawlessly in a temperature range of -40°C to 50°C in wet and dry conditions and at elevations between sea level and 9000 metres. Ergonomically, they are also tight enough to remain in place on the pilot’s arm for up to five days but lightweight enough to be unobtrusive. They are built to provide robust resistance to electrical interference.
Each sleeve is equipped with four vibrating devices similar to those found on cellular telephones. This means that the vibration is felt around the arm’s circumference. Should one vibrating device fail, the others will continue to perform.
Currently, the sleeves allow either wing to drop five degrees before the vibration is activated but the tolerance can be changed if the Solar Impulse team determines that a different value is necessary.
OMEGA’s Solar Impulse Landing Light System
OMEGA had contributed the test bench to the Solar Impulse project and was considering other technological features it might offer. The engineers wanted to offer a system of landing lights but were given an interesting challenge: the Solar Impulse project team said that the entire landing light system could not weigh more than two kilograms!
The OMEGA team managed to create a system which delivers an astonishing watts per weight ratio. On each wing is a set of LED landing lights whose brightness is amplified by a correlation lens. Additional sets of “promotional” lights are positioned along each wing. The lights are all protected by very strong windows which are made from the same resilient plastic used in Swatch watches. Altogether, the landing and promotional lights, their windows, the power transformer and connectors and the wiring weigh about 1.998 kilograms.
As a result, the Solar Impulse’s runway is illuminated, the pilot’s safety is enhanced and the promotional lights create an impressive aesthetic effect – all in a package weighing less than two kilograms.
