In January 2026, Zanzottera Technologies introduced the Z58 engine to the market—a new
propulsion solution specifically engineered for Class B UAV platforms within the 30–45 kg takeoff
weight range.

The Z58 was developed with a clear objective: to deliver a compact, efficient propulsion system
with predictable behaviour, based on a platform already proven in demanding operational
conditions.

A Proven Foundation

The Z58 is directly derived from the renowned Z101 engine platform, which has accumulated more
than ten-thousands of flight hours in diverse operational environments including the most
demanding ones.

The core powertrain and control architecture are inherited from the Z101, including the Cylinder,
head, piston, connecting rod, bearings and rings, Starter-alternator, regulator and Engine Control
Unit (ECUs).

This heritage minimizes technical risk and ensures continuity in reliability, maintenance practices,
and supply chain availability.

Performance and System-Level Testing

The Z58 delivers 5.4 HP at 7000 RPM, with an operational speed range of 3000 to 7000 RPM.
Typical specific fuel consumption (SFC) ranges between 250–290 g/HP/hr, depending on the
mission profile and environmental conditions.

Performance tests were conducted with a propeller focusing on system-level behaviour.

For customers requiring deeper analysis, performance data can be translated into thrust curves and
dynamic simulations.

Technical Specifications: Z58

The Z58 features a square design with a 42mm Bore and 42mm Stroke, optimized for balanced
thermal management and mechanical efficiency.

Feature	Technical Specification
Engine Type	One-cylinder, air-cooled, two-stroke reciprocating
Displacement	58 cc
Bore / Stroke	42 mm / 42 mm
Rated Power	5.5 HP @ 7000 RPM
Operating Speed Range	3000–7000 RPM
Fuel	EN 228 gasoline (RON ≥ 95) with 2% oil premix
Fuel System	EFI (Electronic Fuel Injection)
Ignition System	CDI, dual redundant ignition
Starting System	Starter-alternator, 1500 W
Cooling System	Air-cooled
Lubrication	Fuel–oil premix (2%)
Specific Fuel Consumption	250–290 g/HP·hr
Electrical System Voltage	24–32 V
Propeller Interface	Direct drive, propeller flange
Sensors	CHT, EGT, TPS, Fuel Pressure, IAT, BAP, Redundant CPS, Alternator Temperature, and more
Intended Application	Class B UAVs (30–45 kg MTOW)

High-Power Alternator: The Hybrid Advantage

A key differentiator of the Z58 is its high-capacity 1500W alternator (visible in blue in the engine
assembly). This makes the engine an ideal candidate for hybrid-electric systems and VTOL
(Vertical Take-Off and Landing) platforms.

In a typical VTOL mission, the Z58 provides the necessary power for forward flight while
simultaneously delivering significant electrical energy to recharge the propulsion batteries depleted
during the energy-intensive takeoff phase.

For customers with lower power requirements, a scaled-down alternator configuration is
available upon request to further optimize system weight.

Installation and Configuration Flexibility

While the baseline Z58 configuration prioritizes maximum reliability through extensive reuse of
proven components, alternative configurations are available to meet specific mission requirements.

Customers interested in simplified variants, cost-optimized solutions, or tailored delivery schedules
are encouraged to contact Zanzottera Technologies.

Availability

The Z58 engine has been available for purchase since January 2026.

Summary

The Z58 is designed for UAV platforms where predictability, maintainability, and system-level
understanding are paramount.

Built on experience. Engineered for real operations.

Abstract: The Imperative of Optimized Propulsion

The efficiency of a propulsion system is the single most critical factor determining the success of a professional Unmanned Aerial Vehicle (UAV) mission. It governs maximum flight time, payload capacity, service ceiling, and operational reliability. This technical overview analyzes the thermodynamic and aerodynamic principles that inform propulsion selection, placing specific emphasis on the superior performance profile of fuel-injected two-stroke Internal Combustion Engines (ICE), a domain where Zanzottera Engines leads in technological innovation.

1. Introduction: Propulsion Dynamics and Mission Success

Propulsion systems are the heart of any tactical UAV platform, converting stored energy (chemical, electrical, or solar) into the kinetic thrust required for controlled flight.

The propulsion architecture directly dictates the vehicle’s flight envelope. Whether the mission is Intelligence, Surveillance, and Reconnaissance (ISR), logistical delivery, or large-scale tactical mapping, the propulsion unit must deliver an optimal balance of Power-to-Weight Ratio and Specific Fuel Consumption (SFC).

2. Classification of Standard Propulsion Architectures

UAV propulsion is generally categorized into three main streams, each serving unique operational requirements.

2.1. Electric Propulsion

Electric systems utilize brushless DC motors and advanced battery technologies (LiPo, Solid-State).

• Advantages: Near-silent acoustic signature, minimal maintenance, instant torque.
• Limitations: Critically constrained by the low energy density of batteries (typically $~250$ Wh/kg), severely limiting flight time and operational range.
• Best For: Short-range, small-platform missions, or sensitive urban environments requiring stealth.

2.2. Internal Combustion Engines (ICE)

Reciprocating engines powered by liquid hydrocarbons (Gasoline, JP-5, JP-8).

• Key Advantage: Unmatched energy density of liquid fuel ($~12,000$ Wh/kg). This high energy density is non-negotiable for achieving long-endurance missions and supporting substantial payloads.
• Application: Medium Altitude Long Endurance (MALE) platforms, heavy-lift logistics, and remote area operations.

2.3. Hybrid and Turbine Systems

Hybrid systems merge an ICE generator with electric drive, aiming for flexibility. Micro-Turbines offer extremely high velocity but suffer from a very high SFC, making them unsuitable for endurance roles.

3. The Strategic Advantage of Fuel-Injected 2-Stroke Engines (The Zanzottera Edge)

While electric systems are popular, high-performance, professional-grade UAVs in the tactical space rely on the inherent advantages of the Two-Stroke Cycle—particularly when enhanced by Electronic Fuel Injection (EFI). This core technology is what differentiates Zanzottera Engines.

3.1. Maximum Power-to-Weight Ratio Optimization

The two-stroke cycle generates a power stroke on every rotation of the crankshaft, delivering roughly double the power density of a comparable four-stroke engine. This mechanical simplicity translates directly into reduced parasitic weight, a critical engineering imperative for maximizing payload capacity.

3.2. Electronic Fuel Injection (EFI): Precision Meets Efficiency

Traditional carbureted engines are mechanically incapable of maintaining optimal performance across the rapid changes in altitude, temperature, and air density common in UAV operations. Zanzottera’s advanced EFI systems solve this through a precise Electronic Control Unit (ECU):

• Dynamic Altitude Compensation: The ECU actively monitors barometric pressure and intake temperature, adjusting the fuel map in real-time to consistently maintain the optimal stoichiometric ratio for combustion.
• Fuel Efficiency Gains: Direct injection technology eliminates the inherent inefficiency of older 2-stroke designs—preventing the “short-circuiting” of fresh fuel out the exhaust port. This efficiency improvement can extend mission endurance by 15-20%.

Operational Reliability: EFI ensures guaranteed cold starts and stable, consistent idling regardless of harsh environmental conditions, enhancing overall mission readiness.

4. Critical Performance Metrics for Selection

When evaluating a propulsion system, the following engineering metrics are paramount:

Metric	Definition	Importance for UAVs
SFC	Specific Fuel Consumption (Fuel mass consumed per unit of power/time).	Directly defines mission Endurance. Zanzottera engines are tuned to minimize SFC at cruise.
TBO	Time Between Overhauls.	Defines logistical footprint and operational cost. 2-Stroke simplicity and advanced coatings (e.g., Nikasil) maximize TBO.
Vibration	High-frequency mechanical oscillation.	Critical for stable ISR/Optical payloads. Boxer engine configurations are naturally balanced to mitigate this.

5. Future Outlook and Technological Integration

The trajectory of UAV propulsion is leaning towards further integration of smart, multi-fuel technologies:

• Heavy Fuel Compatibility: Zanzottera systems are being adapted to run efficiently on kerosene-based fuels (JP-5/JP-8), ensuring compatibility with standard military and naval logistics chains.
• Hybrid Power-Trains: Integrating the highly efficient 2-stroke ICE solely as a generator (Hybrid-Electric) to power distributed electric motors, blending the range of fuel with the silence of electric flight.
• AI-Driven Management: Embedding predictive maintenance algorithms within the ECU to monitor component health and forecast fatigue, ensuring zero catastrophic failures.

Conclusion

The selection of a UAV propulsion system is a complex engineering decision that requires matching the engine’s thermodynamic profile to the demands of the operational environment. For missions demanding long endurance, high payload capacity, and consistent reliability in demanding conditions, the fuel-injected two-stroke engine remains the superior architectural choice.

Zanzottera Engines is committed to delivering the highest standards of power density and fuel efficiency required for the next generation of professional aerial platforms.

Visit Zanzottera Technologies Srl for more technical white papers and product specifications.

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