Engineered Propulsion Systems Graflight V-8
{{Short description|American diesel aircraft engine}}
{{Use mdy dates|date=January 2022}}
{{Use American English|date=January 2022}}
| {{Infobox Aircraft Begin
|name = Graflight V-8 |image = |caption = }}{{Infobox Aircraft Engine |type=Liquid-cooled V-8 piston diesel aircraft engine |designer= Michael Fuchs and Steven Weinzierl |manufacturer=Engineered Propulsion Systems |national origin=United States |first run=2014 |major applications=Cirrus SR22 }} |
The Graflight V-8 is an aircraft diesel engine developed by Wisconsin-based Engineered Propulsion Systems
Design
The Graflight V-8 is a liquid-cooled, flat V-8 with steel pistons and compacted graphite iron crankcase for better strength and durability than aluminum at similar weight, increasing time between overhauls to 3,000 hours. It is managed by a Bosch ECU and can run on Jet A, JP-8 or straight diesel fuel. It is intended to be used in general aviation airplanes, small helicopters, military drones, small boats or troop carriers.{{cite web |url= https://eps.aero/the-eps-engine |title= Engine Overview |publisher= Engineered Propulsion Systems}} The engine is specifically targeting the Robinson R44, Beech Bonanza, GippsAero GA8 Airvan, Cessna TTx and Cessna 206 as possible applications.{{cite news |url= http://www.flyingmag.com/eps-diesel-engine-nears-certification |title= EPS Diesel Engine Nears Certification |author= Pia Bergqvist |date= July 7, 2017 |magazine= Flying Magazine}}
The design is a {{cvt|320-450|hp}}, 4.3-liter engine with steel pistons, connecting rods, and crankcase to improve reliability. At {{cvt|650|lb}}, it weighs {{cvt|40 to 50|lb}} more than a conventional aircraft engine, not including the {{cvt|30|lb}} radiator for cooling. It should be 30-40% more expensive to purchase than a comparable avgas engine, but with 30-50% better fuel economy. Its low vibration levels allow the use of composite or aluminum propellers.
The engine's 17:1 compression ratio gives it a best brake specific fuel consumption of less than {{cvt|0.32|lb/hph|g/kWh|0}}, compared to typical avgas engines with {{cvt|0.42|lb/hph|g/kWh|0}}. It is expected that the Graflight V-8 will burn under {{cvt|11|gal/h|L/h}} of fuel at 65% power.{{cite press release |url= http://www.asdnews.com/news-50106/EPS_Making_Progress_on_Certification_of_Vision_350_Flat-V_Diesel_Aero-Engine.htm |date= Jul 9, 2013 |publisher= EPS |title= EPS Making Progress on Certification of Vision 350 Flat-V Diesel Aero-Engine}}
As a direct comparison, the {{convert|350|hp|kW|0|abbr=on}} version of the Graflight V-8 engine will weigh {{cvt|30|to|50|lb|kg|0}} more than the comparable Lycoming TIO-540-AE2A ({{cvt|595|lb|kg}} dry) or Continental TSIO-550-E ({{cvt|{{#expr:442+2*28.2}}|lb|kg}} dry). It will cost 30% more, but with a higher time between overhaul and lower fuel burn, it will have lower operating costs.{{cite news |url= https://www.aopa.org/news-and-media/all-news/2015/october/pilot/f_diesel |title= DIESEL ROUNDS THE BEND NEW FUNDS SPUR NEXTGEN DIESEL ENGINES |date= October 5, 2015 |author= Thomas B Haines |publisher= AOPA}} At normal 75% cruise power, the Graflight V-8 consumes {{cvt|{{#expr:63/5.54*6.79round0}}|lb/h|kg/h}} of fuel, whereas the Continental TSIO-550-E burns {{cvt|{{#expr:114/6.08*5.87round0}}|lb/h|kg/h}}, a reduction of 30%.{{cite web |url= https://eps.aero/the-eps-engine/fuel-consumption/ |title= Fuel Economy |publisher= Engineered Propulsion Systems}}
Development
EPS set out to certify a new-design flat 8 engine, to replace existing {{cvt|320-420|hp}} general aviation gasoline engines, with the aim of reducing fuel costs by 45%.{{cite news |url= https://www.airinsight.com/eps-diesel-progressing-toward-certification/ |title= EPS Diesel Progressing Toward Certification |date= March 26, 2018 |author= Addison Schonland |work= AirInsight}} EPS started work on the design in 2006, a process that took five years. The engine was first flown in May 2014,{{cite web|url= https://www.avweb.com/ownership/engines/eps-files-for-bankruptcy/|title= EPS Files For Bankruptcy|access-date= 12 August 2020|last= O'Connor|first= Kate|work= AVweb|date= 11 August 2020|archive-url= https://archive.today/20200812125545/https://www.avweb.com/ownership/engines/eps-files-for-bankruptcy/|archive-date= August 12, 2020|url-status= live}} first exhibited at the 2017 EAA AirVenture and FAA certification was expected at that time by the end of the year.
Later in 2017 the testing progress was delayed by insufficient funding. By July 2018 it had completed 25 hours of flight testing on a Cirrus Aircraft airplane. At that point the company hoped to attract Fortune 500 investors and planned that a new demonstrator should be ready in the first quarter of 2019.{{cite news |url= https://www.ainonline.com/aviation-news/general-aviation/2018-07-25/eps-continues-make-progress-aero-diesel |title= EPS Continues To Make Progress on Aero Diesel |author= Mark Huber |date= July 25, 2018 |work= AIN online}} The production version of the engine was shown at AERO Friedrichshafen in April 2019 and work continued on environmental and block testing towards the goal of type certification.
Unable to obtain the needed financing to continue operations, the company filed for Chapter 11 bankruptcy protection in August 2020.
Applications
Specifications (Graflight V-8)
{{pistonspecs
|type= V-8 piston diesel aircraft engine
|bore=
|stroke=
|displacement= 4.3L
|length=
|diameter=
|width=
|height=
|weight=
|valvetrain=
|supercharger=
|turbocharger=
|fuelsystem=
|fueltype= Jet A, JP-8 or straight diesel
|oilsystem=
|coolingsystem=liquid cooled
|power={{cvt|350|hp|kW|0}}
|specpower=
|compression=17:1
|fuelcon={{cvt|9.74|to|17.55|gal/h|L/h}} from {{cvt|210|to|350|hp|kW|0}}
|specfuelcon={{cvt|{{#expr:9.74*6.79/210round3}}|to|{{#expr:17.55*6.79/350round3}}|lb/hph|g/kWh}}
|oilcon=
|power/weight=
}}
References
{{Reflist}}
External links
- [http://eps.aero/#/ Company website]