Editing Tractor configuration

{{Short description|Aircraft design in which the propeller is mounted on the front and pulls the craft forward}}
{{more citations needed|date=October 2011}}

[[File:Cessna 172S Skyhawk SP, Private JP6817606.jpg|thumb|The [[Cessna 172]], a tractor configuration aircraft, and the most popular airplane ever produced]]
[[File:TrislanderImage-comp.jpg|thumb|right|A [[Britten-Norman Trislander]] aircraft (with an unusual 3rd tractor engine on the tail) at [[Guernsey Airport]], Channel Islands]]
[[File: Royal Aircraft Factory FE2b profile.jpg|thumb|The [[Royal Aircraft Factory FE2]] is an example of a pusher configuration]]

In [[aviation]], a '''tractor configuration''' is a propeller-driven fixed-wing [[aircraft]] with its [[Aircraft engine|engine]] mounted with the [[Propeller (aircraft)|propeller]] in front, so that the aircraft is "pulled" through the air. This is the usual configuration;  the [[pusher configuration]] places the airscrew behind, and "pushes" the aircraft forward. Through common usage, the word "propeller" has come to mean any airscrew, whether it pulls or pushes the aircraft.

In the [[History of aviation#Wright brothers|early years of powered aviation]] both tractor and pusher designs were common.{{citation needed|date = March 2014}} However, by the midpoint of the [[World War I|First World War]], interest in pushers declined and the tractor configuration dominated. Today, propeller-driven aircraft are assumed to be tractors unless  stated otherwise.

==Origins==
The first successful airplanes to have a "tractor" configuration were the 1907 [[Santos-Dumont Demoiselle]] and [[Blériot VII]].

The first biplane airplane to have a "tractor" configuration was the [[Goupy No.2]] (first flight on 11 March 1909) designed by [[Mario Calderara]] and financed by [[Ambroise Goupy]] at the French firm [[Blériot Aéronautique]].<ref>Mario Calderara, Commander Calderara Glances Backward and Ahead, U.S. Air Services, Volume 15, Air Service Publishing Company, September 1930, page 38</ref> It was the fastest airplane when it was made.<ref>{{Cite web|url=http://www.treccani.it/enciclopedia/mario-calderara_%28Dizionario-Biografico%29/|title=Calderara, Mario in Dizionario Biografico|website=www.treccani.it}}</ref> At that time a distinction was made between a propeller ("pushes the machine", akin to a ship's propeller) and a tractor-[air]screw ("pulls the machine through the air").<ref>{{Cite magazine|url=http://www.flightglobal.com/pdfarchive/view/1910/1910%20-%200319.html|archive-url=https://web.archive.org/web/20150924153754/http://www.flightglobal.com/pdfarchive/view/1910/1910%20-%200319.html|archive-date=24 September 2015|title=Propellers and tractor-screws (reader's question and editor's answer)|id=475|magazine=Flight|date=23 April 1910}}</ref> The [[Royal Flying Corps]] called the tractors "Bleriot type" after [[Louis Bleriot]], and pushers "[[Farman Aviation Works|Farman]] type".

==Firing guns through the propeller==
A disadvantage of a single-engine tractor military aircraft was that it was initially impossible to fire a gun through the propeller arc without striking the blades. Early solutions included mounting guns ([[rifle]]s or [[machine gun]]s) to fire around the propeller arc, either at an angle to the side&nbsp;– which made aiming difficult&nbsp;– or on the top wing of a [[biplane]] so that the bullets passed over the propeller arc.{{citation needed|date = March 2014}}

The first system to fire through the propeller was developed by French engineer [[Eugene Gilbert]] for [[Morane-Saulnier]], and involved fitting strong metal "deflector wedges" to the propeller blades of a [[Morane-Saulnier L]] [[monoplane]], so that bullets fired when a propeller blade obstructed the line of fire were deflected rather than damaging the propeller. It was employed with immediate success by French [[aviator]] [[Roland Garros (aviator)|Roland Garros]] and was also used on at least one [[Sopwith Tabloid]] of the [[Royal Naval Air Service]].{{citation needed|date = March 2014}}

A better solution was a ''gun synchronizer'', which utilized a [[synchronization gear]] to shoot only at instants when the line of fire was unobstructed, developed by aircraft pioneer [[Anthony Fokker]] and fitted to the [[Fokker E.I]] monoplane [[1915 in aviation|in 1915]]. The first British "tractor"  designed to be fitted with synchronization gear was the [[Sopwith 1½ Strutter]]. which entered service in early 1916.{{citation needed|date = March 2014}}

The problem of firing through the propeller's arc was avoided by passing the gun barrel through the propeller's hub or spinner &nbsp;– first used in production military aircraft with the 1917 French [[SPAD S.XII]]&nbsp;{{citation needed|date = March 2014}}– or mounting guns in the wings, as was used from the early 1930s until propeller engines were superseded in the [[jet age]].

==References==
{{reflist}}

==See also==
*[[Pusher configuration]]
*[[Push-pull configuration]]

[[Category:Aircraft configurations]]
[[Category:Tractor aircraft| ]]