Centurion, originally built for the 100000feet altitude on solar power milestone specified by the ERAST project, was the third generation aircraft in the NASA Pathfinder series of electrical-powered flying wing unmanned aircraft. The ERAST program managers had determined that an aircraft based on the Pathfinder/Pathfinder Plus concept would be the lowest risk approach of achieving the altitude goal.[2]
Initially, a quarter-scale model of the Centurion was test flown at El Mirage Dry Lake on March 4, 1997. The full-size Centurion's maiden flight took place at Rogers Dry Lake on November 10, 1998, and lasted a total of 1 hr and 24 minutes. At the time, it weighed in at 1385lb (including a 150lb steel anvil hanging on its centerline to simulate a payload) for its first flight. The flight was nearly flawless and was followed by a second similar performance on November 19, this time before a crowd of VIPs and Media. It lasted 1 hr and 29 minutes. The third and final flight of the low altitude test series took place on December 3. On this flight the vehicle was loaded down to its maximum gross weight of 1806lb to test its weight carrying capability. Total flight time on this flight was 30 minutes, as it was shortened because high winds were anticipated by mid-morning. All of these flights took place on battery power and verified the design's handling qualities, performance, and structural integrity. Following these three flights, NASA decided to expand the aircraft into the Helios Prototype, with work starting in January, 1999.[1] [2]
The design of Centurion resulted in an aircraft that looked very much like the Pathfinder, but with a much longer wingspan of 206feet. Although the Centurion shape resembled the Pathfinder, the structure was designed to be stronger and capable of carrying numerous payloads (up to 600lb) more efficiently. Its wing incorporated a redesigned high-altitude airfoil and the span was increased to 206feet. The number of motors was increased to 14 and the number of underwing pods to carry batteries, flight control system components, ballast, and landing gear rose to four.[2]
| Length ft(m) | 12 (3.6) | 12 (3.6) | 12 (3.6) | 12 (3.6) | 16.5 (5.0) | |
| Chord ft(m) | 8 (2.4) | |||||
| Wingspan ft(m) | 98.4 (29.5) | 121 (36.3) | 206 (61.8) | 247 (75.3) | ||
| Aspect ratio | 12 to 1 | 15 to 1 | 26 to 1 | 30.9 to 1 | ||
| Glide ratio | 18 to 1 | 21 to 1 | ? | ? | ? | |
| Airspeed kts(km/h) | 15–18 (27–33) | 16.5–23.5 (30.6–43.5) | ? | |||
| Max altitude ft(m) | 71,530 (21,802) | 80,201 (24,445) | n/a | 96,863 (29,523) | 65,000 (19,812) | |
| Empty Wt lb(kg) | ? | ? | ? | 1,322 (600) | ? | |
| Max. weight lb(kg) | 560 (252) | 700 (315) | ±1,900 (±862) | 2,048 (929) | 2,320 (1,052) | |
| Payload lb(kg) | 100 (45) | 150 (67,5) | 100–600 (45–270) | 726 (329) | ? | |
| Engines | electric, 2 hp (1.5 kW) each | |||||
| No. of engines | 6 | 8 | 14 | 14 | 10 | |
| Solar pwr output (kW) | 7.5 | 12.5 | 31 | ? | 18.5 | |
| Supplemental power | batteries | batteries | batteries | Li batteries | Li batteries, fuel cell | |
This article contains material that originally came from the web article "Unmanned Aerial Vehicles" by Greg Goebel, which exists in the Public Domain.