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Engine INSTallation And INtegration

Periodic Reporting for period 3 - EINSTAIN (Engine INSTallation And INtegration)

Reporting period: 2018-07-01 to 2019-06-30

"Nowadays, almost all General Aviation piston-powered aircrafts are powered by Avgas fuel. For decades, piston engines like Lycoming and Continental were allowed to burn only this type of fuel, which is characterized by highoctane values, very low vapor pressure indexes and high costs because of its poor production quantity, tracked and certified production and high performances. The “compression ignition” engine can provide a fuel consumption reduction from 30% to 50% compared to Avgas engine. An additional benefit of the replacement of Avgas piston engine with a diesel engine is obtained due to the reduced fuel price. This “compression ignition” piston engines are able and certified to operate with kerosene and/or Jet fuels, so their use is justified in areas, such as Europe, Africa, Russia, China and many others, where aviation gasoline (Avgas, also known as 100LL) cost is significantly higher than jet fuels. Therefore the objective of this project is to demonstrate the feasibility of an efficient “diesel” engine installation on a FAR/EASA Part23, 9 to 11 seats twin engine aircraft configuration and reduce as much as possible the related increase in drag, respect to a conventional engine, by using Computational Fluid Dynamics (CFD) in the design phase. In order to achieve this goal the SR460, a six-cylinders, air/oil-cooled turbo-diesel engine produced by SMA, will be used as reference and installed on the TECNAM P2012 TRAVELLER aircraft.
The main advantages are reported as following:
• The average fuel consumption will be of around 45kg/hr/engine against an average of 130kg/hr of a turboprop engine;
• P2012 will be the first twin engine aircraft available in both ""Avgas"" and ""kerosene"" capable variants;
• P2012 with SR460 will have a very competitive acquisition cost, comparable to the same-passengers’ capability of the single engine turboprop.
Thanks to EINSTAIN project, TECNAM can complete the construction of the first twin-engine aircraft powered both diesel and Avgas.
A diesel engine is a novel solution for TECNAM that opens new commercial scenarios for P2012 (reference aircraft) and for brand new aircrafts. Operational flexibility and performance saving due to the innovation are main objectives, for design of new aircrafts and their competitiveness."
Detailed specifications and requirements have been provided. In particular, installation requirements from the engine manufacturer has been collected.
Proved knowledge and methodology have been developed to understand how to improve the process of power unit integration, what activities are on the critical path and which are the key parameters for the trade-offs.
Nacelle aerodynamic analysis/design for the new SR460 diesel engine installation has been performed.
Assessment of nacelle air-intakes/exhausts effectiveness, with the aim maximizing mass flow rate to radiators in supporting the engine cooling for the SR460 diesel engine installation, has been performed.
Assessment of the numerical analyses & design tools versus ground test data has been performed.
A “diesel-baseline” configuration was delivered and analyzed by using CFD to evaluate nacelle drag, eventual areas with flow separation, the effectiveness of air intakes and radiator cooling efficiency for the SR460 installation.
Production drawings and tooling/jigs design for parts and components have been elaborated.
Computational analysis (load, strength, performance) on all the parts subject to the flight and inertia loads (i.e. engine mount, nacelle and so on) has been performed.
After a long market analysis, made in cooperation with more than 70 dealers worldwide, TECNAM consider that the future of General Aviation will no longer count on gasoline powered engines for different reasons including, but not limited to: gasoline price, limitations of AKI91 aviation gasoline on the TIO/TEO-540 turbocharged engine series, difficulty in fuel supply and complete absence of aviation gasoline in many worldwide countries.
For this reason, it appears evident that designing and certifying a new aircraft on 21st Century needs to take into account these aspects. Actually:
“if an Airline Company wants to carry up to 9 passengers with single pilot operations and with no access to AVGAS, simply have no choice on the market and no business”.

The selection of a good partner for engine manufacturing is essential and linked to the following requirements:
• An engine manufacturer that should have experience in heavy fuel piston engine certification under EASA;
• An engine manufacturer that has a big and capillary diffused after sales service worldwide;
• An engine manufacturer that is able to provide a “born for aircraft” engine, suitable for wing nacelle installation, in comparison with all the other players mainly derived from automotive diesel engines and so high installation volumes.
It is evident that the above mentioned points result in high investments and consequent high engine acquisition price. For this reason, TECNAM demonstrated that even where access to Avgas is available, the use of JET fuel powered piston engine is still convenient in the medium/long term.

Following the main considerations:
• the spread between the avgas and Jet-A cost is different in USA and Europe;
•the diesel engine has generally lower fuel consumption in all the flight phases (average of 58lt/h against 83lt/h at same cruise power output: 260hp) and so lower emissions and absence of lead, actually burnt in all avgas fuels engines;
• the oil consumption is lower as well due to the modern technology and component sealing.

With the previous assumptions, also taking into account that diesel piston engines have consistent differences in purchasing price (generally +50% for the same rated power in comparison with an Avgas operated one) and in maintenance, an airline company can recover all the related costs in 3.000 flight hours (in USA) or 366hr (in Europe). This means that, after 3.000 hours (or only 366 hours in Europe), the airline company will have the investment of the diesel engine installation paid and will start increasing the profit which can be quantified in 57$ per passenger (USA) or 127€/passenger (EU) due to the lower operating costs, for every single flight2.
The possibility to offer the same platform powered by Avgas and JET fuel (diesel) engines will be the winning strategy for all worldwide scenarios.

The project is a significant experience for diesel engine in General Aviation.
Wider operative scenarios/runaways and airports allow diesel propelled aircraft to connect people from remote areas to main hub, thus have a huge social impact and a commercial opportunity for TECNAM; for this P2012 with SMA Engine represents the unique single pilot heavy fuel, able to operate for public transportation without restrictions.