343:
A lack of sunny days delayed flight testing, but in all, 28 flights were made. The
Sunrise would climb slowly at first until its solar cells cooled down and their efficiency increased. On its 28th flight the aircraft was destroyed when it was flown too close to a cumulus cloud at about 8,000 ft
143:
batteries available would be sufficient to sustain flight using a radio-control model glider. Early experimental projects proved the concept sound and in 1973 Boucher turned his attention to the creation of a high-altitude solar-powered aircraft that would have unlimited endurance.
372:. While in hospital he resigned from AstroFlight and sold his interests in the company to his brother Bob Boucher who continued work on the second Sunrise aircraft. After recuperating, Roland Boucher returned to work at Hughes Aircraft on classified military programs.
179:
electric motor, the first motor of its kind in the world. The aircraft would use no batteries and, instead, would descend at night from its operating altitude to about 10,000 ft (3,048 m) at dawn, before solar energy was once again available for climb.
147:
Boucher explained the project to his superiors at Hughes
Aircraft in 1972 and after reviewing it, the company released the project to Boucher in 1973. Boucher took a leave of absence from Hughes to pursue the project and joined his brother, Bob Boucher, at
360:
DARPA and
Lockheed proposed a follow-on design to the Sunrise to be powered at night by batteries instead of just gliding. Roland Boucher designed the second aircraft using higher efficiency solar panels that were more aerodynamically smooth.
220:
was a very low 4 ounces per square foot (0.011 kg/sq m). The aircraft structure was built from spruce, balsa and maple. Due to their roughness the solar cells were only mounted on the aft two-thirds of the wing's upper surface.
200:
Roland
Boucher took on the task of the structural design, aerodynamics, telemetry, control and navigation. He also designed the integration of the solar panel, electric motors, gearbox and the propeller. He selected an Eppler 387
315:
designed and built telemetry transmitter and receiver. The standard S&O six channel radio had channels for elevator, rudder, motor on and off and solar cell operating mode. The solar cells could be set for either
171:
solar cells producing only 10% efficiency, Boucher calculated that his project would need to be able to fly on about 0.5 kW (0.7 hp). The aircraft was envisioned as an uncrewed
183:
Boucher saw the
Sunrise as a proof of concept for a follow on aircraft that would be capable of remaining aloft for months at an altitude of 100,000 ft (30,480 m).
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operation. The telemetry functions provided gave data on motor current, motor voltage, motor RPM, airspeed and two heading references from a
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264: in (2 mm) balsa. This construction resulted in a balsa spar box with tapered spruce caps. The leading edge was covered with
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139:, Roland Boucher began design work on an electric-powered aircraft concept in November 1970, calculating that the contemporary
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274: in (0.8 mm) balsa to form a leading edge D spar. The trailing edge was formed by two 2 in (51 mm) wide
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Flight testing commenced in 1974 at
Bicycle Lake, California. The first flights were conducted on battery power, using a
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715:
197:, with the contract specifying a "proof of concept aircraft powered solely by incident sunlight on the wing surfaces."
127:. The first prototype was destroyed on its 28th flight by turbulence. The improved Sunrise II flew the following year.
340:
launch to 20 ft (6 m). On its first flight the aircraft reached 500 feet, before returning for a landing.
115:
First conceived in
November 1970, the Sunrise first flew on 4 November 1974 from Bicycle Lake, a dry lakebed on the
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116:
308:. The 32 ft (10 m) span wing weighed 5 lb (2 kg) and was capable of loads up to 100 pounds.
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Roland
Boucher had become physically exhausted from his work on the initial Sunrise and he suffered from
176:
684:
224:
The wing spars were built from spruce spar caps with maple doublers at all attachment points and two
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304: in (3 to 10 mm) vertical spar sections in between the ribs. The covering was 1/2 mil
473:, 6:1 belt drive, powered by 1,872 5 cm diameter round solar cells, 0.60 hp (0.45 kW)
467:
356:
Project
Sunrise had demonstrated the feasibility of solar powered flight to extreme altitudes".
216:
was 32 ft (10 m) and the aircraft had a gross weight of 22 lb (10 kg). The
205:
for the wing. The solar cells were 5 cm (2.0 in) round commercial units provided by
175:
that would have an operating altitude of 73,000 ft (22,250 m), powered by a single
369:
194:
102:
30:
156:. After successfully flying an electric drone carrying a 5 lb (2 kg) payload on a
209:. The actual airframe was constructed by a team under expert model builder Phil Bernhardt.
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8:
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254: in (3 to 10 mm) balsa strips on the wing spars. The ribs were made from
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The success of the flights that had been completed allowed
Boucher to state:
344:(2,438 m) and the associated turbulence broke the aircraft's structure.
325:
124:
45:
217:
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337:
149:
55:
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was funded by DARPA commencing in January 1974 and administered by
443:
202:
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Unmanned aviation: a brief history of unmanned aerial vehicles
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1975 improved version for high altitude flight demonstration
305:
157:
108:
technology demonstrator and the first aircraft to fly on
1004:
AIAA-84-1429 History of Solar Flight Robert J. Boucher
284: in (0.8 mm) sheets forming a triangle with
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2-bladed, 2 ft 6 in (0.76 m) diameter
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The Sunrise II first flew on 27 September 1975 from
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Aircraft of comparable role, configuration, and era
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234: in (2 mm) balsa shear webs attached to
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600:
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747:
702:
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540:Solar-Powered Aircraft Developments Solar One
500:73,000 ft (22,000 m) Design ceiling
405:
652:
650:
512:0.0023 lb/sq ft (0.011 kg/m)
678:
676:
1061:1970s United States experimental aircraft
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398:Project Sunrise Prototype #2 (Sunrise II)
152:, a small model airplane manufacturer in
392:Project Sunrise Prototype #1 (Sunrise I)
164:, they then moved onto Project Sunrise.
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368:. He was admitted to intensive care at
1038:
494:14 mph (22 km/h, 12 kn)
331:
682:
1026:Photo of Sunrise showing solar cells
691:from the original on 28 October 2009
395:Initial aircraft first flown in 1974
13:
433:14 ft 4 in (4.36 m)
14:
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1010:
685:"Solar-Power Research and Dryden"
135:While working as an engineer at
1066:Single-engined tractor aircraft
998:
506:150 ft/min (0.76 m/s)
117:Fort Irwin Military Reservation
130:
1:
657:Newcome, Laurence R. (2004).
547:
191:Lockheed Aircraft Corporation
167:Using commercially available
1031:Photo of Sunrise on take-off
347:
7:
683:Curry, Marty (March 2008).
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386:
10:
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406:Specifications (Sunrise I)
16:1974 experimental aircraft
1017:Official website archives
21:
965:Boucher, Roland (n.d.).
922:Boucher, Roland (n.d.).
879:Boucher, Roland (n.d.).
837:Boucher, Roland (n.d.).
794:Boucher, Roland (n.d.).
754:Boucher, Roland (n.d.).
714:Boucher, Roland (n.d.).
614:Boucher, Roland (n.d.).
567:Boucher, Roland (n.d.).
366:congestive heart failure
967:"Project Sunrise pg 16"
924:"Project Sunrise pg 10"
839:"Project Sunrise pg 11"
616:"Project Sunrise pg 13"
460:27 lb (12 kg)
454:22 lb (10 kg)
439:32 ft (9.8 m)
418:General characteristics
413:Project Sunrise website
1056:Solar-powered aircraft
881:"Project Sunrise pg 8"
796:"Project Sunrise pg 4"
756:"Project Sunrise pg 2"
716:"Project Sunrise pg 9"
569:"Project Sunrise pg 1"
468:Samarium-Cobalt magnet
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177:Samarium–cobalt magnet
370:Santa Monica Hospital
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195:Sunnyvale, California
31:Experimental aircraft
1071:Lockheed Corporation
1046:AstroFlight aircraft
990:: CS1 maint: year (
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162:Northrop Corporation
22:AstroFlight Sunrise
458:Max takeoff weight:
332:Operational history
311:Control was via an
99:AstroFlight Sunrise
154:Venice, California
535:Mauro Solar Riser
523:Electric aircraft
381:Las Vegas, Nevada
106:electric aircraft
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498:Service ceiling:
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328:for navigation.
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73:4 November 1974
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34:Type of aircraft
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137:Hughes Aircraft
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65:Roland Boucher
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492:Cruise speed:
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975:. Retrieved
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885:the original
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800:the original
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764:. Retrieved
760:the original
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724:. Retrieved
720:the original
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160:project for
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103:experimental
98:
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87:Number built
1021:archive.org
485:Performance
477:Propellers:
464:Powerplant:
338:bungee cord
326:sun compass
150:AstroFlight
131:Development
110:solar power
56:AstroFlight
1040:Categories
977:2009-09-23
934:2009-09-23
891:2009-09-23
844:2009-09-23
806:2009-09-23
766:2009-09-23
726:2009-09-23
695:2009-09-15
666:2009-09-23
626:2009-09-23
579:2009-09-23
548:References
448:Eppler 387
377:Nellis AFB
121:California
437:Wingspan:
411:Data from
348:Aftermath
214:wing span
207:Heliotech
173:sailplane
62:Designer
986:cite web
943:cite web
900:cite web
853:cite web
815:cite web
775:cite web
735:cite web
689:Archived
635:cite web
588:cite web
517:See also
387:Variants
322:parallel
81:Retired
444:Airfoil
431:Length:
379:, near
299:⁄
289:⁄
279:⁄
269:⁄
259:⁄
249:⁄
239:⁄
229:⁄
203:airfoil
78:Status
318:series
425:Crew:
306:Mylar
158:DARPA
27:Role
992:link
949:link
906:link
859:link
821:link
781:link
741:link
641:link
594:link
466:1 Ă—
427:None
97:The
1019:on
320:or
294:to
244:to
193:of
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