Aviation Event – Solar Impulse Completes Pacific Crossing

Feats of exploration are not something that get a huge amount of attention these days. Whether it is because they don’t happen very often or because they don’t overcome the noise of modern life is not clear. One project has done a great job of sharing itself with the world while also bringing a message about renewable technologies. Solar Impulse landed in California on the 9th leg of their round the world voyage. Rob Edgcumbe saw the arrival and visited with them. Hayman Tam provides additional images.

The Solar Impulse project is an ambitious project to create an aeroplane that can circle the world without using any fuel. The brainchild of Bertrand Piccard and Andre Borschberg, the journey to where they are today has taken over 16 years. Piccard is no stranger to adventure. He completed the first round the world balloon flight with Brian Jones in 1999. His father had taken submersibles to the deepest part of the oceans. Having achieved one round the world record is obviously not enough for Bertrand. He wants to do another and this time the motivation is not just achieving the flight but sharing with the world his vision for renewable energy.

© Rob Edgcumbe - Global Aviation Resource

This is the second aircraft Solar Impulse has built. The first was a smaller version that demonstrated the concept of operations but didn’t have the range capabilities to make the trip across the large oceans. It led to the creation of the current airframe. It underwent much testing but, as the team freely admit, it is still an experimental aircraft and each flight is a test flight.

The round the world flight started in 2015 and got as far as Hawaii from its starting point in Abu Dhabi. The longest leg of the flight was from Japan to Hawaii and it was on this five day mission, flown by Andre, that the batteries experienced some damage due to heat. This was the longest the aeroplane had flown by far and so the discovery of some new issues was not unexpected. However, it did cause sufficient damage that repairs would take long enough to take the program beyond the weather window. Therefore, the aeroplane stayed on the ground in Hawaii until the new season arrived.

That window came recently and the next leg was attempted. A change in plan meant that the arrival point in the US was moved to Mountain View in the heart of Silicon Valley rather than Phoenix. While originally the landing point, Phoenix has not been removed from the schedule and will be the next stop after a comparatively short flight. The duration of this leg was just under three days and it was the first thorough test for the modifications made during the down time in Hawaii.

The flight proved to be a big success. The modifications worked well and the aircraft (and pilot since this was Bertrand’s first long overwater flight) stood up to the task well. Strong tailwinds meant that they reached the coast of California early on Saturday April 23rd. Since the aircraft is very light, it is most appropriate to take off and land it when conditions are at their smoothest. Consequently, the landing was scheduled at Moffett Federal Field at midnight. This left a lot of time for flying around the coast including the chance to get some footage of the aircraft flying over the iconic Golden Gate Bridge.

As midnight approached, the conditions had calmed down as predicted and Solar Impulse appeared in the night sky over Moffett. It approached from the west and its path brought it into view above the famous Hangar One, one of the airship hangars built for the US Navy when they had a large airship program. A gentle pattern around the field took the aircraft on to final approach. The low speed at which it operates meant that there was plenty of time to see it manoeuvring on to its approach path. It carries a number of lights and, when established on final approach, additional LED lights burst into life on the leading edge making it very conspicuous.

As it came close it was the first chance the assembled crowd had to hear the aircraft. The four large propellers turn very slowly and make an odd noise. If you have ever stood close to a wind turbine, you know the whooshing sound that those large blades make. This is a similar sound but faster. Someone commented on it sounding a big like an egg whisk. The aeroplane quickly passed by and made a smooth but firm contact with the runway on its main gear leg. A team of support crew swept out on to the runway to chase it on a series of electric bicycles.

The aircraft was secured and lifted on to dollies to allow it to be towed back by hand and manoeuvred into its parking space. When everything was set, the crew removed the panel from the cockpit side and Bertrand was able to step out. After three days in a confined space, he was remarkably energetic. After hugging his wife and greeting the team, he immediately headed into a series of interviews with the assembled media team. The questions focused on many areas but the message always seemed to come back to one overriding theme.

With passion and vigour, Bertrand focused on the importance of trying something different and difficult. He did not lose sight of the environmental message of the program and its importance for many aspects of society’s future but he also wanted to inspire people to take a chance. He feels that avoiding challenges leaves people feeling disappointed and ultimately unhappy. By stepping into the unknown, he proposes that the result of making that leap provides greater satisfaction, irrespective of the results achieved.

The presentations continued for a long time with Bertrand showing no sign of tiring despite it being early in the morning and he having not slept properly for three days. Eventually things wrapped up and the crew started putting the aircraft away. At the time of the landing, they had completed half of the temporary hangar. This inflatable structure is something that they can take with them when they go to airports that do not have an available hangar that can accommodate an aircraft with the wingspan of a 747 (although only weighing about 2.5 tonnes). By the following day the hangar was assembled and the aircraft stored inside.

This provided protection from the winds that picked up following the landing and delayed the departure. Originally scheduled for the Tuesday morning, at time of writing it was delayed until Friday. Meanwhile, the time on the ground allowed the crew to work on the aircraft. Within the hangar, air conditioning packs were connected to the batteries to keep them at an optimum temperature despite the warmth of the day (which made the hangar temperature quite high). The team is run by a guy called Nils. He has a reputation for constantly looking around to see what needs to be done. His behaviour was likened to that of a meerkat. As a result, a fluffy meerkat toy is mounted in the cockpit to keep an eye over the aircraft while it is flying. This toy is called Nilsy.

The team also received a steady stream of visitors. While media attention was still high, a lot of time was spent with representatives of the partner organizations that support the project in various different ways. This can be financial support or technical support. One partner is Nestle who provide the food for the flights. Bertrand demonstrated the storage locations in which the food is kept and how he is able to eat and drink during the flight. He had found that he did not eat all the food that he had available during the crossing and could have kept flying! His favourite foods were the breakfast pack that he would have when he saw the sunrise and the energy drink that he found great for reinvigorating himself shortly before landing. Water consumption was important because the high altitude and oxygen supplies resulted in drying out.

While sleep was not possible during the flight, both Bertrand and Andre had developed techniques for keeping themselves in shape while airborne. Self hypnosis and yoga were beneficial and they could take twenty minute naps throughout the flight in order to rest carefully and then maintain awareness for extended periods. The cockpit does not provide much room to move but the seat does recline which allows for the yoga exercises.

When asked about the plans for the aircraft once the round the world flight is complete, Bertrand suggested some ideas that they are currently working on. The aircraft was designed for a life of 2,000 hours but will have consumed only about 600 by the time they are done. They are contemplating converting it to unmanned usage for telecommunications relay demonstrations. The extended flight at high altitude is not a demanding regime from an airframe load position but the limitations will be related to UV exposure. It will be a useful demonstration exercise though.

The flight routing and timings are very dependent on weather conditions. Currently the next stop is due to be Goodyear airport in Phoenix. A stop at JFK in New York is also planned. The Atlantic crossing will then follow. Where they make landfall will be determined closer to the time based on the winds across the ocean. That will be the last long overwater leg of the mission. However, everyone is well aware that each flight is still an expansion of the envelope and that plenty of risks remain. The mission control team are very conscious of this and meticulously plan each flight.

To stay abreast of the progress of the flights, check out www.solarimpulse.com and follow them on Facebook and Twitter. Best of luck to the team in the continuing mission and in sharing the larger message of the project.

Rob and Hayman would like to offer their thanks to everyone in Solar Impulse for their support during the time in California, especially Elke and Victoire.