The Self-Launcher Fuel Injection System

Retractable Self-Launcher

The retractable pylon thrust system, using the SOLO® 2625 02i two-stroke 625cc inline twin-cylinder liquid-cooled aircraft engine with electronic fuel injection and dual sparkplug high-voltage ignition system, mated to and in house optimally designed propeller makes light work out of take-off climb at MTOW.

The new generation electronically fuel injected system ensures for a much more economic fuel consumption, allowing approx. 1, 5 hrs. of engine operation. This robust system gives a power output of 47 kW (64 hp).


Standard System Features

  • Two throttle bodies with fuel injectors managed by the Trijekt Engine Control Unit (ECU)
  • ECU  equipped with the following duplex-redundant components: engine speed sensor, throttle position sensor, injectors 
  • External fuel pumps electronics unit allow ECU to monitor fuel pumps as well
  • Integrated 500W alternator and electric starter
  • Dual electronic high-voltage ignition, mapped ignition system
  • NGK B7HS, air gap at electrodes 0.7mm spark plugs
  • Dedicated 12v  15.6Ah sealed lightweight LiFePO4 engine battery 
  • Integrated CAN-BUS communication and fault memory for error messages and problem diagnostics.
  • Multiple V-belt belt drive with propeller and engine RPM monitoring to detect belt slip 
  • Pylon extension and retraction via developed actuator system with an integrated positioning pylon positioning system
  • Automatic cooling and retraction after shutdown
  • Tuned stainless-steel exhaust with silencer
  • Fire warning system
  • Two-blade carbon-fibre 1.44 m [4.72 ft] diameter propeller
  • Automatic centring of propeller after shutdown



Within the JS2/JS5 fuselage our engineering team has managed to accommodate room for the solo 2625-02i neo engine within the confines’ of our aerodynamicists Johan Bosman, performance models.

For the first time self-launch customers can have this convenience without a performance loss.

Climb Performance



JS started designing their own fuel injection engine not knowing the SOLO was busy designing their own upgraded fuel injected engine called SOLO 2625 02i neo. Once this became known the JS2 SL design was put on hold until the improved SOLO system could be tested.

The improved engine from Solo has addressed all the problems from the old engine. Solo’s 2625 02i neo engine together with JS’s designed system including fuel system, reduction/damping of vibration and safety, will ensure a consistent pleasant flying experience, even exceeding the pilot’s expectations

Fuel tanks

Because the fuselage of the JS2 and JS5 is designed to still be competitive there are severe space restrictions. For this reason some of the fuel has to move to the wings into integral tanks with automatic connections between the fuselage and the wings for fuel transfer and venting.

Capacities of fuel tanks are approximately 12 litre each, therefore a totaling 36 litres per system. This allows approx. 1,5 hours of engine running time.

In an effort to reduce leaks and save space JS has looked to the automotive industry and incorporated a submersible fuel pump system for the fuel supply. This has various advantages such as reducing the complexity of the fuel system outside the fuel tanks.

For transfer the system uses a venturi pumps such as found in large airliners to transfer fuel from the wing tanks to the centre tank. This venturi pump is a mechanical pump with no moving parts that has almost no chance of failure during operation making it the safest method of transferring fuel from one tank to another

Reduction in vibration of the engine

With older 2 stroke engines vibration is a problem, especially when a balancer shaft is not part of the design. The effect is that the damping of the engine rest on the shoulders of the designer. The vibration of the solo 2650 engine was modelled and the damping optimised to offer the best protection to the fuselage.

In order to achieve this, the engine is mounted on a frame that fixed the system into place. To reduce the effect of the propeller the system incorporated five v-belts to allow for slippage and movement between the propeller and the engine.

A novel extension system is used that pushes the engine out from the bottom of the fuselage rather than pull the engine into position. The main effect of this is to reduce the chance of the spindle failing during operation, resulting in a spectacular failure once the engine is shut down.