View source for Thorp T-18

{{Short description|American homebuilt aircraft}}
{{Use mdy dates|date=February 2022}}
{{Use American English|date=February 2022}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{{Infobox aircraft
|name= T-18
|image=T18 in flight.jpg
|caption=Thorp T-18 in flight
|type=[[homebuilt aircraft|Amateur-built aircraft]]
|manufacturer=[[Eklund Engineering]]
|designer=[[John Thorp]]
|first_flight= 1963
|introduction=
|produced=
|number_built=400
|variants=
}}
[[File:Thorp T-18 amateur-built C-GEMP 02.JPG|thumb|right|Thorp T-18]]
[[File:Thorp T18 VH-OTM.jpg|right|thumb|T-18]]
The '''Thorp T-18''' is an American, two-place, all-metal, plans-built, [[homebuilt aircraft]] designed in 1963 by [[John Thorp]].<ref name="Eklund">{{cite web|url = http://www.thorpt18.com/|title = Eklund Engineering|accessdate = 2009-05-26|last = Eklund Engineering|authorlink = |year = n.d.}}</ref><ref name="WDLA11">Bayerl, Robby; Martin Berkemeier; et al: ''World Directory of Leisure Aviation 2011–12'', page 98. WDLA UK, Lancaster UK, 2011. {{ISSN|1368-485X}}</ref><ref name="WDLA15">Tacke, Willi; Marino Boric; et al: ''World Directory of Light Aviation 2015–16'', page 105. Flying Pages Europe SARL, 2015. {{ISSN|1368-485X}}</ref>
The aircraft was originally designed as an open cockpit aircraft, powered by a military surplus [[Lycoming O-290|Lycoming O-290G]] ground power unit engine, but evolved into a fully [[bubble canopy|bubble canopied]] aircraft powered by engines of up to {{convert|200|hp|kW|0|abbr=on}}.<ref name="Eklund" />
==Design and development==
The T-18 was designed to be easily constructed from sheets of [[aluminum]], and use a modified [[Lycoming Engines|Lycoming]] [[Lycoming O-290|O-290G]].  It was originally designed with an open cockpit and with the [[cylinder head]]s protruding through the engine [[cowling]] in the interest of simplicity. Even as originally designed, the cruising speed was quite high. The design showed great potential for higher performance and so modifications were created to install larger, cowled Lycomings and a bubble canopy. These modifications allow a T-18 with {{convert|125|hp|kW|0|abbr=on}} to cruise at {{convert|160|mph|km/h|0|abbr=on}} and higher-powered examples to cruise in excess of {{convert|200|mph|km/h|0|abbr=on}}. Some aircraft have been constructed with retractable landing gear.<ref name="Bowers">Bowers, Peter M. ''Guide to Homebuilts – 9th Edition'', pages 124–127. Tab Books, 1984. {{ISBN|0-8306-2364-7}}</ref><ref name="Plane and Pilot">Plane and Pilot: ''1978 Aircraft Directory'', page 157. Werner & Werner Corp, Santa Monica CA, 1977. {{ISBN|0-918312-00-0}}</ref>
These performance improvements made the T-18 one of the most popular homebuilt designs of the 1970s and early 1980s until the [[Van's Aircraft]] RV kitplane series came on the market.<ref name="Bowers"/><ref name="Plane and Pilot"/>
The T-18 was designed to use the {{convert|125|hp|kW|0|abbr=on}} Lycoming O-290G Ground Power Unit. At the time the T-18 was developed, these engines were inexpensive and widely available as military surplus generator motors. When converted for aircraft use they are virtually identical to the O-290D or O-290D2 aircraft engines.<ref name="Eklund"/>
Other Lycoming engines can be used, including the [[Lycoming O-320]], [[Lycoming O-340]], [[Lycoming O-360]] and the [[Lycoming IO-360]].<ref name="Eklund"/>
T-18 plans were available to builders from [[Eklund Engineering]], which was also developing a laser-cut kit version and as of 2009 had [[aileron]], [[Flap (aircraft)|flap]] and [[empennage]] kits. [[Classic Sport Aircraft]] at one time supplied plans, parts, and kits for the S-18 and the S-18T tricycle gear version, but went out of business in 2014.<ref name="Eklund"/><ref name="ClassicPrice">{{cite web|url = http://www.classicsportaircraft.com/price.html|title = Kit and Component Pricing|accessdate = 2009-05-26|last = Classic Sport Aircraft|authorlink = |year = n.d.|url-status=dead|archiveurl = https://web.archive.org/web/20081206122216/http://www.classicsportaircraft.com/price.html|archivedate = 2008-12-06}}</ref> [[Thorp Central]] acquired the assets of Classic Sport Aircraft and now provides S-18 plans and parts.<ref name="ThorpCentral">{{cite web|url = http://www.thorpcentral.com/|title = Thorp Central |accessdate = 24 November 2014|last = Grahn|first = Jim and MaryKay|date = }}</ref>
By 2011 over 1600 sets of plans had been sold and 400 examples were flying.<ref name="WDLA11"/>
==Operational history==
One T-18, N455DT, was built by [[Donald Taylor (aviator)|Donald Taylor]] of California and flown around the world from [[Oshkosh, Wisconsin]], in 1976. This was the first successful [[circumnavigation]] of the world by a homebuilt aircraft. Taylor subsequently flew N455DT to the geographical North Pole, using a Sperry hybrid inertial navigation system.<ref name="EAAMuseumT18">{{cite web|url = http://www.airventuremuseum.org/virtual/interactive/innovations/thorp/|title = Thorp T-18|accessdate = 2009-11-21|last = EAA AirVenture Museum|authorlink = |year =}}</ref>
Clive Canning flew another T-18 from Australia to England earlier the same year.<ref name="COF1976">{{cite web|url = http://www.century-of-flight.net/Aviation%20history/aviation%20timeline/1976.htm|title = World Aviation in 1976|accessdate = 2009-11-28|last = Century of Flight|authorlink = |year = |archive-date = May 15, 2009|archive-url = https://web.archive.org/web/20090515114542/http://www.century-of-flight.net/Aviation%20history/aviation%20timeline/1976.htm|url-status = dead}}</ref>
==Variants==
;T-18
:Original model
;T-18W
:Modified T-18, with changes designed by Lou Sunderland to provide a 2" (5 cm) wider fuselage.
;T-18C
:Modified T-18, with changes designed by Lou Sunderland to provide a "convertible" wing that rotates back against the fuselage for trailering or storage.
;T-18CW
:T-18 with wider fuselage and folding wing.
;S-18
:Similar to T-18CW, with modified airfoil and other minor changes. The Sunderland changes were made in collaboration with Thorp.<ref name="KitplanesDec2011">Vandermeullen, Richard: ''2012 Kit Aircraft Buyer's Guide'', Kitplanes, Volume 28, Number 12, December 2011, page 48. Belvoir Publications. {{ISSN|0891-1851}}</ref>
[[File:ThorpS18T.jpg|thumb|Thorp S-18T]]
;S-18T
:[[Tricycle gear|Tricycle landing gear]] version<ref name="WDLA11"/><ref name="WDLA15"/><ref name="ClassicPrice"/><ref name="KitplanesDec2011"/>
==Specifications (S-18 with Lycoming O-360)==
{{Aircraft specs
|prime units?=imp
<!-- if you do not understand how to use this template, please ask at [[Wikipedia talk:WikiProject Aircraft]] -->
|ref=''Eklund<ref name="EklundSpecs">{{cite web|url = http://home.jps.net/~eeicorp/id47.htm|title = T-18 specifications|accessdate = 2009-05-27|last = Eklund Engineering|year = n.d.|url-status=dead|archiveurl = https://web.archive.org/web/20080228173158/http://home.jps.net/~eeicorp/id47.htm|archivedate = 2008-02-28}}</ref> & Classic Sport Aircraft<ref name="ClassicSpecs">{{cite web|url = http://www.classicsportaircraft.com/performance.html|title = Performance|accessdate = 2009-05-27|last = Classic Sport Aircraft|year = n.d.|url-status=dead|archiveurl = https://web.archive.org/web/20081207074446/http://www.classicsportaircraft.com/performance.html|archivedate = 2008-12-07}}</ref> & Thorp Central<ref name="s18_thorp_central">[http://thorpcentral.com/the-s-18 "S-18,"] Thorp Central, retrieved January 20, 2024</ref>''
<!--
General characteristics
-->
|crew=one
|capacity=one passenger and 600 lb (271 kg) loaded weight
|length ft= 18
|length in= 10
|length m=5.77
|span ft=20
|span in=10
|span m=6.35
|height ft=5
|height in=1
|wing area sqft= 86
|wing area sqm= 8
|empty weight lb=1000
|gross weight lb=1600
|more general=
<!--
Powerplant
-->
|eng1 name=[[Lycoming O-360]]
|eng1 hp=180
|eng1 kw=135
|prop name=constant speed propeller,
||prop blade number=2
|prop dia in=72
|prop dia m= 1.83
<!--
Performance
-->
|max speed mph= 200
|max speed kmh= 320
|cruise speed mph= 180
|cruise speed kmh= 292
|stall speed mph= 63
|stall speed kmh= 101
|range mi= 540
|range km=875
|range note=, 900 mi (1,458 km) with optional wing tanks
|climb rate ftmin= 1500
|climb rate ms= 7.6
|wing loading lb/sqft=18.6
|wing loading kg/m2=90
|power/mass=8.9 lb/hp (0.19 kW/kg)
|more performance=
<!--
Armament
-->
|armament=<!-- if you want to use the following specific parameters, do not use this line at all-->
|avionics=
}}
==See also==
{{aircontent
|see also=
|related=
*[[Thorp T-211]]
|similar aircraft=
*[[Jeffair Barracuda]]
*[[Mustang Aeronautics Mustang II]]
*[[Smyth Sidewinder]]
*[[Stoddard-Hamilton Glasair II]]
*[[Van's Aircraft RV-6]]
|lists=
|similar engines=
}}
==References==
{{reflist|30em}}
{{commons category|Thorp T-18}}
<!-- ==External links== -->
[[Category:Homebuilt aircraft]]
[[Category:1960s United States civil utility aircraft]]
[[Category:Low-wing aircraft]]
[[Category:Single-engined tractor aircraft]]
[[Category:Aircraft first flown in 1963]]
[[Category:Thorp aircraft|T-018]]
[[Category:Aircraft with fixed conventional landing gear]]