View source for Physics:Solar-Powered Aircraft Developments Solar One

{{Short description|British solar powered aeroplane}}
<!-- This article is a part of Wikipedia:WikiProject Aircraft. Please see Wikipedia:WikiProject Aircraft/page content for recommended layout. -->
{|{{Infobox aircraft begin
 | name=Solar One
}}{{Infobox aircraft type
 | type=[[Physics:Electric aircraft|Electric aircraft]]
 | national origin={{wipe|United Kingdom}}
 | manufacturer=Solar-Powered Aircraft Developments
 | designer=David Williams
 | first flight=13 June 1979
 | introduced=1978
 | retired=1979
 | status=
 | primary user=
 | more users= <!--Limited to three in total; separate using <br /> -->
 | produced= <!--years in production-->
 | number built=One
 | developed from= 
 | variants with their own articles=
}}
|}
The '''Solar-Powered Aircraft Developments Solar One''' is a British mid-wing, [[Engineering:Experimental aircraft|experimental]], manned [[Physics:Electric aircraft|solar-powered aircraft]] that was designed by David Williams and produced by Solar-Powered Aircraft Developments under the direction of Freddie To. On 13 June 1979 it became one of the first solar-powered aircraft to fly, after the unmanned [[Engineering:AstroFlight Sunrise|AstroFlight Sunrise]] and the manned [[Physics:Mauro Solar Riser|Mauro Solar Riser]], and the first successful British solar-powered aircraft.<ref name="flightglobal">"UK's first solar aircraft takes off", ''Flight International'', 30 June 1979, Page 2336.[http://www.flightglobal.com/pdfarchive/view/1979/1979%20-%202438.html]</ref><ref name="astroflight">Robert J. Boucher; "History of Solar Flight", AIAA/SAE/ASME 20th Joint Propulsion Conference, 1984, AIAA paper 84-1429.{{cite web |url=http://www.astroflight.com/pdfs/SolarHistory.pdf |title=Archived copy |access-date=2011-03-06 |url-status=dead |archive-url=https://web.archive.org/web/20110707180738/http://www.astroflight.com/pdfs/SolarHistory.pdf |archive-date=7 July 2011 |df=dmy-all }}</ref><ref name="jane1980">''Jane's All the World's Aircraft 1980-81'', Jane's, 1980, Page249.</ref>

==Design and development==
Freddie To was a member of the [[Engineering:Kremer prize|Kremer prize]] committee who started his own project to produce a [[Engineering:Human-powered aircraft|human-powered aircraft]] to compete for the prize. Its structure comprised a wooden frame covered with heat-shrunk Solarfilm [[Engineering:Model aircraft|model aircraft]] film. The wing was built in three sections, a centre section and two outer wing panels to simplify storage and transport. The wing spar is a laminated [[Biology:Spruce|spruce]] girder box-spar design. The tail surfaces are quickly removable for storage.<ref name="flightglobal" /> The resulting aircraft, at {{convert|230|lb|kg|0|abbr=on}}, proved too heavy for human-powered flight and so To converted it to solar power.

A nose-mounted pod powerplant was installed consisting of four {{convert|1|hp|kW|0|abbr=on}} permanent magnet 36 V [[Physics:Direct current|DC]], 12 A Bosch electric motors, powered by a {{convert|65|lb|kg|0|abbr=on}} Nickel-cadmium battery pack of 24 cells with a total capacity of 25 AH, connected in series to give a maximum (open-circuit) output voltage of approximately 29 V. The motors drive a {{convert|63|in|cm|0|abbr=on}} two-bladed propeller via a 3:1 bicycle-chain reduction gear. The propeller turns at a maximum of 1,100 rpm, decreasing with battery discharge. Power is controlled with a simple on/off switch.

To recharge the batteries, 750 solar cells of 3 inch diameter were installed at a cost of £6,000. At that time solar cells were very expensive. They were the most costly part of the aircraft and had to be limited in capacity to remain within the project budget of [[Finance:Pound sterling|£]]16,000.<ref name="flightglobal" /><ref name="astroflight" />

The output from the solar cells is not sufficient to sustain flight. Before flight they are used to charge the batteries. The batteries then provide power for takeoff and initial climb. The installed batteries provide for a climb of eight minutes plus a two-minute cruise allowance.<ref name="flightglobal" />

==Operational history==
The first flight attempt took place at Lasham Airfield, Hampshire, {{wipe|United Kingdom}} on 19 December 1978. The propeller pitch was incorrectly set and the attempt achieved only a short hop. At the hands of pilot Ken Stewart, a successful flight took place on 13 June 1979, covering just under {{convert|0.75|mi|km|1|abbr=on}}.<ref name="flightglobal" /> The aircraft lifted off at {{convert|18|to|20|kn|km/h|0|abbr=on}} and reached {{convert|35|kn|km/h|0|abbr=on}} and {{convert|80|ft|m|0|abbr=on}} in height. A second flight on the same day by Bill Maidment achieved a speed of {{convert|42|kn|km/h|0|abbr=on}}. All flights were made on battery power that had been supplied on the ground from the installed solar cells.<ref name="flightglobal" /><ref name="astroflight" />

A planned flight across the English Channel was abandoned when it was found that the aircraft did not meet its endurance targets.<ref name="astroflight" />
<!-- ==Aircraft on display== -->

== Specifications (Solar One) ==
{{Aircraft specs
|ref=History of Solar Flight<ref name="astroflight" /> and Flight Global<ref name="flightglobal" />
|prime units?=imp<!-- imp or kts first for US aircraft, and UK aircraft pre-metrification, met(ric) first for all others. You MUST choose a format, or no specifications will show -->
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|crew=one
|capacity=
|length m=
|length ft=22
|length in=0
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|span ft=68
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|wing area sqm=
|wing area sqft=260
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|aspect ratio=17.8:1
|airfoil=Wortman FX180
|empty weight kg=
|empty weight lb=230
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|eng1 number=4
|eng1 name=Bosch
|eng1 type= 36 volt DC, 12 amp permanent magnet electric motor
|eng1 kw=<!-- prop engines -->
|eng1 hp=1<!-- prop engines -->
|eng1 note= with output via 3:1 reduction chain drive

|prop blade number=2
|prop name=
|prop dia m=<!-- propeller aircraft -->
|prop dia ft=5
|prop dia in=3
|prop note=

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|max speed kts=42
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|ceiling ft=80
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}}

==See also==
{{aircontent
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|see also=
|related=<!-- related developments -->
|similar aircraft=
*[[Engineering:AstroFlight Sunrise|AstroFlight Sunrise]]
*[[Physics:Mauro Solar Riser|Mauro Solar Riser]]
*[[Physics:MacCready Solar Challenger|MacCready Solar Challenger]]
|lists=<!-- related lists -->
}}

==References==
{{reflist}}


[[Category:Solar-powered aircraft]]
[[Category:Photovoltaics]]
[[Category:Mid-wing aircraft]]
[[Category:Single-engined tractor aircraft]]

{{Sourceattribution|Solar-Powered Aircraft Developments Solar One}}