Ivchenko AI-20

{{Short description|Soviet turboprop engine}}  {{infobox aero engine | name=AI-20 | image=Ivchenko AI-20M Szolnok 2010 1.jpg | caption= Ivchenko AI-20M turboprop engine |engine_type=Turboprop |manufacturer=Ivchenko/ZMKB Progress, PMZ (Perm), AI22 also in KMPO plant |designer= |national_origin=Soviet Union |first_run= |major_applications= {{ubl | Antonov An-10|Antonov An-12|Ilyushin Il-18}} |produced= |number_built= |developed_from= |variants_with_their_own_articles= }} The '''Ivchenko AI-20''' ({{langx|ru|Ивченко АИ-20}}) is a Soviet turboprop engine developed by the Ivchenko design bureau in the 1950s. It has been built in large numbers, serving as the powerplant for both the Antonov An-12 transport and the Ilyushin Il-18 airliner.

==Design and development== The AI-20 was the first gas turbine engine developed by the design bureau led by Oleksandr Heorhiiovych Ivchenko based at Zaporizhzhia, USSR, which had previously concentrated on small piston engines such as the Ivchenko AI-14 and AI-26 radials. It was designed as a prospective powerplant for the new, large Ilyushin Il-18 airliner and the Antonov An-10, to be powered by four turboprops, in competition with the Kuznetsov NK-4 engines. Both engines were tested on the preproduction batch of 20 Il-18s, but the Ivchenko engine was chosen for full production,<ref name="Stroud">{{cite book |last1=Stroud |first1=John |title=Soviet transport aircraft since 1945. |date=1968 |publisher=Putnam |location=London |isbn=9780370001265 |page=113 |edition= 1st}}</ref> possibly due to a crash caused by an inflight failure of an NK-4 engine, and possibly due to the desire for the engines of the Ukrainian An-10 to also be built in Ukraine.<ref name="aviation.ru">{{cite web |last=Alexandrov |first=Nikolai |title=Тот самый "НК" |url=http://www.aviation.ru/engine/NK/story1/index.php |website=aviation.ru |access-date=23 March 2019 |archive-url=https://web.archive.org/web/20110514040332/http://www.aviation.ru/engine/NK/story1/index.php |archive-date=14 May 2011 |location=Moscow |language=ru}}</ref>

The Il-18B was powered by four Ivchenko AI-20A Series 1 turboprops, each providing a takeoff power of 2,985 kW (4,000 shp) and sustained power of 2,090 kW (2,800 shp) at cruise altitude. Early Il-18A production had initially been fitted with Kuznetsov NK-4 engines, but they were soon exchanged for AI-20s. Later Il-18B production featured AI-20A Series 2 engines, with the same power ratings, but with technical improvements, thus older machines were updated with the Series 2 powerplants. The AI-20s drove four-bladed variable pitch reversible props with a diameter of 4.5 meters (14 feet 9 inches), featuring prominent propeller spinners, and hydraulic actuation for prop pitch. The engines were mounted above the wing and featured integrated fire extinguishers. The engines were started with electric motors, the power for the motors being provided by a ground cart.<ref name="airvectors"/>

The AI-20 is a single-shaft turboprop with a ten-stage axial compressor and a three-stage power turbine, and is designed to run at a constant speed.<ref name="Gunston aero p81">{{cite book |last1=Gunston |first1=Bill |title=World encyclopaedia of aero engines |date=1987 |publisher=Stephens |location=Wellingborough |isbn=978-0-85059-717-2 |edition= Reprint |page=81}}</ref> A big problem with early production engines was the poor reliability of the AI-20 engines, which had a time between overhauls (TBO) in the range of 600 to 750 hours. The AI-20K engine variant was finally introduced, with a TBO of 2,000 hours – unimpressive by modern standards, but a big improvement. One issue that was never addressed was noise; turboprops are relatively noisy and high noise levels were a problem for the passengers. As mentioned, the overhaul life of the engine was initially poor compared with contemporary western engines, being reported as 600–750 hours in 1964,<ref name="Flight160164p85">{{cite journal |title=Under the Il-18's Cowlings |journal=Flight International |date=16 January 1964 |volume= 85 |issue= 2862 |page=85 |url=http://www.flightglobal.com/pdfarchive/view/1964/1964%20-%200122.html |access-date=23 March 2019}}</ref> but was later improved by continuous development to 8,000 hours, with a service life of 22,000 hours in the AI-20D series 5M.<ref name="ivchenko-progress.com">{{cite web |title=HISTORY OF SE IVCHENKO-PROGRESS FOUNDATION |url=http://ivchenko-progress.com/?page_id=22&lang=en |website=ivchenko-progress.com |publisher=Ivchenko-Progress |access-date=23 March 2019 |language=en}}</ref>

Serial production was carried out at Zaporizhzhia (Motor Sich) and at Perm Engine Plant (UEC-Perm Engines), USSR in 1958, also being built under licence in China as the '''WJ-6'''. About 14,000 AI-20s have been built in total.<ref name="Ivenchko-Progress">{{cite web |title=Zaporozhye Machine-Building Design Bureau Progress State Enterprise Named After Academician A.G. Ivchenko (SE Ivchenko-Progress): History Oof SE Ivchenko-Progress |url=http://www.ivchenko-progress.com/welcome.do?id=12&lang=en |website=ivchenko-progress.com |date=2007 |publisher=Ivenchko-Progress |access-date=23 March 2019 |archive-url=https://web.archive.org/web/20110726150817/http://www.ivchenko-progress.com/welcome.do?id=12&lang=en |archive-date=26 July 2011 |url-status=dead }}</ref>

==Variants== ;AI-20A series 1: :Initial production variant for early version of IL-18 producing 2,985 kW (4,000 shp). TBO was 200–400 hrs. ;AI-20A series 2: :Improved production variant with same power ratings but technical improvements; older airplanes were updated with the Series 2 engines. TBO was (600–750 hrs) ;AI-20K: :Reliability and durability was addressed with this much improved variant. TBO went up to 2,000 hours. This became the standard production variant. ;AI-20M: :This variant was a significant improvement over the earlier engine variants in all respects. The AI-20M raised takeoff power from 2,985 kW (4,000 shp) to 3,169 kW (4,250 shp), improving takeoff performance under "hot and high" conditions and permitting higher takeoff weights. Higher continuous power ratings were also attained (2,700 shp) which made for more efficient cruise. Beyond these, the AI-20M also had good reliability, was lighter, and in particular featured much improved SFC.<ref name="airvectors">{{cite web |title=The Ilyushin Il-18 & Il-38 |url=http://www.airvectors.net/avil18.html |website=www.airvectors.net |access-date=23 March 2019}}</ref> ;AI-20D: :This variant saw significant improvement in power output. Fuel economy was also marginally improved. AI-20D is also often referred to as AI-20D series 4. Power was uprated to 5,180 shp. ;AI-20D series 5: :This variant builds on the previous success of the series 4 variant. Most performance parameters remained the same with the only major improvement being in the area of reliability and durability. The TBO/Service life was improved to 6000 hrs / 20,000 hrs respectively. ;AI-20D series 5M or AI-20DM: :This is the final variant developed. The AI-20DM is essentially the same with the AI-20D series 5, the only difference being in the power setting. The AI-20DM is derated to 4,750 shp (take-off power) which allows the engine to have extended life and increased TBO. The Time before overhaul (TBO) is consequently increased to 8,000 hrs with a service life of 22,000 hrs.<ref name="Motorsich.ua">{{cite web |title=AI-20 |url=http://motorsich.com.ua/AI-20 |website=motorsich.com.ua |access-date=23 March 2019}}</ref>

==Applications==

===AI-20=== *Antonov An-8 *Antonov An-10 *Antonov An-12 *Antonov An-32 *Beriev Be-12 *Ilyushin Il-18 *Ilyushin Il-38 *Tupolev Tu-4 (KJ-1 AEWC)

===WJ-6=== *Shaanxi Y-8 *Shaanxi Y-9 *Qing-6 (Chinese upgraded Be-6 airframe) *AVIC AG600 amphibian *Xi'an KJ-600 carrier onboard delivery

==Specifications (AI-20D series 5) ==  {{jetspecs   |ref=Jane's All The World's Aircraft 1993–94,<ref name=JAWA93-94>{{cite book |title=Jane's all the World's Aircraft 1993–94 |editor1-last=Taylor |editor1-first=Michael J.H. |editor2-last=Lambert |editor2-first=Mark |editor3-last=Munson |editor3-first=Kenneth |date=1993 |publisher=Jane's Information Group |location=Coulson, Surrey, UK |isbn=978-0710610669 |edition= 84th |page=650}}</ref> Motor Sich website,<ref name="Motorsich.ua"/> Aircraft engines of the World 1970<ref name=Wilkinson70>{{cite book |last=Wilkinson |first=Paul H. |title=Aircraft engines of the World 1970 |year=1970 |publisher=Paul H. Wilkinson |location=Washington D.C. |edition= 21st |page=217 }}</ref> |type=Single-shaft turboprop |length={{cvt|3096|mm}} |diameter={{cvt|450|mm}} (intake casing)<ref name=Wilkinson70/><br /> *'''Width''': {{cvt|842|mm}} *'''Height''': {{cvt|1180|mm}} |weight={{cvt|1040|kg}} |compressor=10-stage axial compressor with 4 bypass valves for starting and transient ratings |combustion=Annular with 10 burner cones |turbine=3-stage axial flow |fueltype=Aviation Kerosene fuels such as JP-4 |oilsystem=Pressure type feed, fully recirculating |power={{cvt|4250|shp|kW|order=flip}} (equivalent) for take-off at 12,300 rpm at sea level / ({{cvt|3900|shp|kW|order=flip}} + {{cvt|529|lbf|kN|order=flip}})<br /> :*'''Max. cruise power:''' {{cvt|2600|kW|shp}} (equivalent) at {{cvt|630|km/h|mph kn}} at {{cvt|8000|m}} *'''Engine operating rpm:''' 12,300 rpm *'''Engine ground idle:''' 10,400 rpm |thrust= |compression=7.6:1 (take-off) to 9.2:1 (cruise) |bypass= |aircon={{cvt|20.7|kg/s|lb/s}} at 12,300 rpm |turbinetemp='''TIT''' max. {{cvt|900|C|K|order=flip}} at sea level; '''JPT''' {{cvt|560|C|K|order=flip}} |fuelcon= |specfuelcon=<br /> :*'''Take-off s.f.c.:''' {{cvt|0.529|lb/hph|kg/kWh|order=flip}} :*'''Cruise s.f.c.:''' {{cvt|0.434|lb/hph|kg/kWh|order=flip}} |power/weight={{cvt|1.87|shp/lb|kW/kg|order=flip}} (equivalent take-off power)<ref name=Wilkinson70/> |thrust/weight= }}

==See also== {{aircontent  |see also= |related= |similar engines=*Allison T56 *Bristol Proteus *General Electric T64 *Pratt & Whitney Canada PW100 *Rolls-Royce Tyne *  |lists= *List of aircraft engines }}

==References== {{Reflist}}

==External links== {{commons category}} *[http://www.motorsich.com/eng/products/aircraft/tr/ai-20/ Motorsich] {{Webarchive|url=https://web.archive.org/web/20140325192812/http://www.motorsich.com/eng/products/aircraft/tr/ai-20/ |date=2014-03-25 }}

Category:1950s turboprop engines Category:Ivchenko-Progress aircraft engines