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Why a Diesel?

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Why a Diesel Engine?

Benefits of the diesel-cycle engine include:

Desirable Fuel Type: Low flammability and worldwide availability of Jet-A or diesel fuel is valued in all applications; current aviation fuel for the IO-360 and other high compression engines is leaded and will eventually be made unavailable by the EPA (Environmental Protection Agency), making those engines unusable.

Fuel Efficiency: The Delta Diesel Engine is designed to BSFC (brake specific fuel consumption) of .37 lb/hp/hr versus current avgas-powered aviation engine book BSFC of .59 lb/hp/hr at 75% and above.

Lower Fuel Cost: 20-30% more range per gallon. Also, cost per gallon of Jet-A averages $0.09 less than 100LL aviation fuel in the U.S. The price differential is much greater in Europe.*

Electromagnetic Noise Elimination: Absence of an ignition system reduces interference with navigational and communication systems; for military applications, this is desirable for tactical reasons.

Simplicity of Operation: Single-lever power operation (no mixture control).

Durability: Inherent in diesels because diesel and jet fuels provide more lubricity and because no electrical system (magnetos or electronic ignition) is required.

Smoothness: A two-stroke diesel has four power pulses per revolution with continuous positive torque applied to the propeller (versus two pulses per revolution with approximately 30 degrees of negative torque in four-stroke/four-cylinder engines).

Liquid-Cooling: Reduces overcooling in descents from altitude. Also, reduced thermal variance in operation allows tighter manufacturing tolerances, leading to increased power and fuel efficiency.

Durability: The 2-stroke piston-ported design reduces the parts count by eliminating valves, valve train and cam shaft. Lliquid cooling reduces fatigue and unified cylinder and block design eliminates studs, gaskets and bolts.

Reliability: Fail-safe design aspects have been incorporated, including backup air, redundancy of fuel pumps and limited operation at reduced power without coolant.

Small Size and Light Weight: The V-design is stout and compact; use of advanced materials and focus on low weight as a design criteria will result in a V-8 model producing nearly 1 horsepower per pound. The V-4 is at least 30 lbs lighter than the equivalent aviation engine (comparisons at fully installed weight) and hundreds of pounds lighter than equivalent marine diesels. For new aircraft designs, the V configuration also allows a more rounded cowling, permitting aerodynamic and propeller noise reduction improvements.

* As a recent e-mail stated: "In Europe and particularly the U.K. economic benefits are more pronounced due the prohibitive price of both petrol and avgas ... Jet A ... does not cost more than £0.30 per liter ($0.45) as opposed to petrol or avgas at £0.80 per liter ($1.28). Also given the improved economy of your engine it is not difficult to show a saving of £5000.00 ($8000.00) per year in fuel on only 210 hours engine time. Conservative hourly savings work out at £25.00 per hour ($40.00) in a Velocity or Cozy MK4. £100.00 ($160.00) of fuel will carry you 2100nm with the DeltaHawk or 630nm with the Lycoming 360. While in practice these saving may not be quite so large they will still be considerable, probably over 50%. ... The incredible savings this side of the water would probably make conversion from other engine types a very real economic proposition even with the cost of a new engine!!"

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