Learjet 28
{{short description|Business jet aircraft}}
{{Infobox aircraft
|name = Learjet 28/29
|image = Learjet 28-29.jpg
|caption =
|type = Business jet
|manufacturer = Learjet
|designer =
|first_flight = August 24, 1977
|introduction =
|retired =
|status = Retired
|primary_user =
|more_users =
|produced = 1977–1982
|number_built = 9
|unit cost =
|developed_from = Learjet 25
|developed_into = Learjet 31
}}
The Learjet 28 is an American eight-to-ten-seat (two crew and six to eight passengers), twin-engine, high-speed business jet, intended to be the successor to the Learjet 25. The Learjet 29 is identical except for the addition of a long-range fuel tank, resulting in the reduction of the capacity to six (two crew and four passengers). Both were manufactured by Learjet and were marketed under the Longhorn name.[http://www.airliners.net/info/stats.main?id=264 A history of the LJ23-LJ29 series on Airliners.net]
History
The first flight of the Learjet 28 took place on August 24, 1977.{{Cite web |url=http://www.wingsoverkansas.com/history/article.asp?id=199 |title=Learjet company timeline |access-date=2007-01-08 |archive-url=https://web.archive.org/web/20061231131658/http://www.wingsoverkansas.com/history/article.asp?id=199 |archive-date=2006-12-31 |url-status=dead }} The Learjet 28/29 was based on the Learjet 25, and received a completely new wing fitted with winglets which resulted in improved performance and fuel economy. The new wing was designed for the Learjet 55, and the Learjet 28 was originally planned to be a testbed for the wing, not a production type, but after the prototypes demonstrated excellent climb performance and the ability to operate at {{convert|51000|ft|m|abbr=on}} (the first business jet to do so), it was decided to offer the Learjet 28 and 29 as production aircraft. FAA certification was awarded to both the Learjet 28 and 29 on January 30, 1979.Griffiths Air-Britain Aviation World Autumn 2022, p. 189.
The Learjet 28/29 was the first production jet aircraft to utilize wingletsReynolds's The Learjet “Longhorn” Series—The First Jets With Winglets (entering service in 1977).
Both models were commercially unsuccessful, showing reduced range compared to the Learjet 31, as the addition of winglets required the deletion of the earlier model's wingtip tanks, and they sold mainly to customers with a requirement for good altitude performance. Only five production Learjet 28s, and four Learjet 29s, were constructed before production ceased in August 1982.Taylor 1982, p. 367 Both types were subsequently replaced by the Learjet 31.
The first production aircraft was used by Neil Armstrong to set five aerospace records.{{cite news |last1=Richardson |first1=Joshua |title=Historic Learjet donated to Armstrong Air & Space Museum |url=http://dayton247now.com/news/local/historic-learjet-donated-to-armstrong-air-space-museum |accessdate=7 August 2020 |work=Dayton 24/7 Now |date=5 August 2020}}
Noise compliance
In 2013, the FAA modified 14 CFR part 91 rules to prohibit the operation of jets weighing 75,000 pounds or less that are not stage 3 noise compliant after December 31, 2015. The Learjet 28 is listed explicitly in Federal Register [http://www.gpo.gov/fdsys/granule/FR-2013-07-02/2013-15843/content-detail.html 78 FR 39576]. Any Learjet 28s that have not been modified by installing Stage 3 noise compliant engines or have not had "hushkits" installed for non-compliant engines will not be permitted to fly in the contiguous 48 states after December 31, 2015. 14 CFR §91.883 Special flight authorizations for jet airplanes weighing 75,000 pounds or less – lists special flight authorizations that may be granted for operation after December 31, 2015.
Specifications (Learjet 28)
{{Aircraft specs
|ref=Jane's Civil and Military Aircraft Upgrades 1994–95Michell 1994, pp. 317–318.
|prime units?=imp
|genhide=
|crew=2
|capacity=8 passengers
|length m=14.51
|length ft=
|length in=
|span m=13.35
|span ft=
|span in=
|height m=3.73
|height ft=
|height in=
|wing area sqm=
|wing area sqft=264.5
|airfoil =
|empty weight kg=3750
|empty weight lb=
|gross weight kg=
|gross weight lb=15000
|fuel capacity=
|eng1 number=2
|eng1 name=General Electric CJ-610-8A
|eng1 type=turbojet
|eng1 kn=
|eng1 lbf=2950
|perfhide=
|max speed kmh=
|max speed mph=549
|max speed kts=
|max speed mach=
|max speed note=at 25,000 ft (7,620 m)
|cruise speed kmh=
|cruise speed mph=470
|cruise speed kts=
|cruise speed note=,econ cruise at 51,000 ft (15,545 m)
|stall speed kmh=165
|range km=
|range miles=1309
|range nmi=
|ceiling m=
|ceiling ft=51000
|climb rate ms=
|climb rate ftmin=
|more performance=
|avionics=
}}
See also
References
;Notes
{{reflist}}
;Bibliography
- {{cite magazine |last=Griffiths |first=Andrew |title=Learjet – The End of an Era: Part 2: Wingletted Wonders |magazine=Air-Britain Aviation World |date=Autumn 2022 |pages=189–193 |issn=1742-996X}}
- {{cite book |editor-last=Michell |editor-first=Simon |title=Jane's Civil and Military Aircraft Upgrades 1994–95 |year=1994 |location=Coulsdon, UK |publisher=Jane's Information Group |isbn=0-7106-1208-7}}
- {{cite book |editor-last=Taylor |editor-first=John W. R. |editor-link=John W. R. Taylor |title=Jane's All the World's Aircraft 1982–83 |year=1982 |location=London |publisher=Jane's Yearbooks |isbn=0-7106-0748-2}}
- {{cite journal |last1=Reynolds |first1=Peter T. |title=The Learjet "Longhorn" Series—The First Jets With Winglets |year=1979 |journal=SAE Technical Paper 790581 |series=SAE Technical Paper Series |volume=1 |publisher=Jane's Yearbooks |doi=10.4271/790581}}
External links
{{commons category|Learjet 28 and 29}}
- [http://www.airwar.ru/enc_e/aliner/ljet28.html Specs of LJ28]{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }}
- [http://www.airwar.ru/enc_e/aliner/ljet29.html Specs of LJ29]{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }}
- [http://www.airliners.net/info/stats.main?id=264 A history of the LJ23-LJ29 series on Airliners.net]
{{Learjet}}
Category:1970s United States business aircraft