An onboard video of a human-powered flight for distance of 60 km in 2 hour 36 min., was shared by a champion team of Japan International Birdman Rally.

“60km Human Powered Flight” caught on an onboard camera uploaded to YouTube by Birdman House Iga (BHI)
SOURCE: https://www.youtube.com/watch?v=wZ_s2lGmpMw

The Birdman House Iga (BHI), which the champion team of human-powered aircraft category of Japan International Birdman Rally (JIBR) 2019 has shared an onboard view of a long human-powered flight such as historical DAEDALUS’s and Gossamer Albatross’s flights again. This had been taken by an onboard camera during 60 km flight over triangle course in 2019 summer. This flight is the longest flight in Japan as far as anyone knows as of now. Unfortunately, the longest flight is unofficial record, because JIBR rules do not comply to FAI rules. However, in simple comparison of distance, It is longer flight than Fédération Aéronautique Internationale (FAI; World Air Sports Federation) class I-C distance around a closed circuit record, i.e. 58.66 km with Michelob Light Eagle by the MIT DAEDALUS team. Additionally, this video may be the longest human-powered flight video caught on an onboard camera, superseding the previous 40 km onboard video by BHI. This camera view is also indistinct caused by a distorted mirror image by a heat rejection film applied on the windscreen. Most of voice is small and unclear, so it is difficult to listen that. On the video, BHI added some information, which are GPS log of the flight path, heading angle, temperature, altitude, heart rate, and ground speed. Those information must help our understanding the flight.

Schematic flight path of the BHI’s 60 km flight in 2019 overlaid on a map. Scale of the flight path on the map is rough.
SOURCE:
Original map (Geospatial Information Authority of Japan/国土地理院): https://maps.gsi.go.jp/vector/#10.811/35.328908/136.119178/&ls=hillshade1%2C0.3%7Cvpale2&disp=11&d=l
Flight path, captured and traced from the “60km Human Powered Flight” from YouTube:
https://www.youtube.com/watch?v=jhxQibYkUJk

For well understanding the flight, a schematic illustration of the flight path is shown above. You should pay attention to that this figure is inexact. However, it should help us to understanding the 60 km flight.

The JIBR 2019 triangle course was consisted of three points, starting platform and two turn points. Those turn points were set at 19 km apart from the platform and 22 km apart from each other. When a flight distance reached at 19 km and 41 km, recoding of the flight distance was frozen until completion of turning at each turn point. Participants were not needed to fly outside of a triangle having those three point as its vertices, except turning around the marks. So, for example, a concave hexagonal (or three-pointed star shaped) flight path was even allowed. In addition, participants were allowed to fly over the course in both clockwise and counter-clockwise.

The BHI’s flight path shown in the video was almost isosceles triangle, so it was efficient to around the course. The pilot flew over the course in a counter-clockwise way from the platform on the east shore. The first leg is from the platform to the first turn point near off shore Chikubu island. The video shows that the flight path of the first leg was relatively unsteady especially in the first 5 km. In the same period, ground speed was also relatively fluctuated between 17.5 km/h and 26.5 km/h. Those may have been caused by wind. In the second half of the first leg, variations of the flight path and the ground speed were grown calmer. The first turning was smooth although required power was increased to keep its altitude. It proved that the champion HPA had good stability and maneuverability.

The flight went into the second leg after approval of the first turn and it was 54 min. after the starting. The second leg is set from the first nothern turn point to the second southern turn point where is near off shore Oki island. The flight path of the second leg looks like curved smoothly. It may have been intent to keep distance from a cape according to the schematic map. The ground speed of the second leg was the fastest all over the flight path. The ground speed of the second leg was the fastest in whole the flight path. It was kept almost over 30 km/h and reached more than 40 km/h at its maximum. It may have been caused by a tailwind. It is empirically supported by JIBR participants that a tailwind increases required power to fly HPA without a probable theory. However, actual heart rate was not significantly increased and actual altitude was made higher against the expectation. Those may mean that thermal helped the pilot. The second turning at the end of the second leg with high speed also required more power further. The voice recorder caught the pilot’s harsh breathing although he had amazing physical strength. In fact, his heart rate was increased up to 173 bpm as well as the first turning, which was highest heart rate throughout the flight.

In 1 hour 33 min. after starting, his third leg was started. The third leg is between the Oki island to the platform and similar direction to return way of the previous 40 km flight in 2017. The previous flight path was through left side of Take island and turned to right. However, he selected clearly another flight path in the 2019 flight. He went between the Take island and a shore on the almost straight. It is notable difference. Ground speed during and after the second turning was rapidly decreased from 35 km/h to less than 20 km/h. A headwind should have caused it. It is also known empirically that a headwind decreases required power contrary to a tailwind. In addition to thermal same as the second leg, some of excess power would have uplifted the HPA up to danger height before the pilot knew. So he stopped or reduced rotation of his propeller to descend to allowable height. Headwind was continued up to the last 1 km of the flight and kept his ground speed slower than average. Especially in the first half of the third leg, ground speed was kept almost less than 17 km/h and minimum ground speed was 12.5 km/h, which was of course minimum in whole the flight. He needed 1 hour 3 minutes to fly over the third leg in the end. When he finished, his breath was regained calm even though he had kept outputting average 180 Watts for 2 hours 36 minutes. It seemed that he left an enough margin of his physical strength after the amazing 60 km flight.

Some comments have already been put on the video. BHI replied some of them. According to the BHI’s comments, BHI participated JIBR 2021 with their new HPA, which is smaller and faster than the HPA won JIBR 2019. The new HPA must be the one described in a previous article posted in the last year. And BHI will upload an onboard HPA video of their flight in JIBR 2021 after broadcasting JIBR 2021 on TV.

Like & Reference;

• 60km Human Powered Flight|BHI|YouTube

poor English better than Japanese – thank you