The Retractable Electric System
The Retractable Electric System (RES) is not only a sustainer but also a self-
launcher up to a maximum weight of 575 kg.
The system is high voltage designed with two removable batteries stowed in the fuselage.
The system is developed in partnership with well-known aircraft engine producer, SOLO
Aircraft Engines, designed for comfort, safety, operation flexibility and impressive performance.
The fully automated system is easy to operate with the power setting adjustable with a
rotary dial on the control panel.
TECHNICAL DATA
System Specifications
| Electric Motor | EMRAX 208 |
| Propeller type | Technoflug KS-1C-120-R-065-S |
| Maximum Static thrust | 90 daN |
| Maximum RPM | 4350 |
| Max power for take-off | 40 kW |
| Max continuous climb power | 25 kW |
| System weight (no batteries) | +/- 24kg (53 lbs) |
Battery Specification
| Battery Type | EMECTRIC BM 384 |
| Battery configuration | 96S4P |
| Battery Voltage | 270V-400V |
| Usable Energy (available energy decreases with high power settings) | 3.4 – 4.2 kWh per battery |
| Battery weight | 25kg (55.1 lbs) |
| Maximum number of batteries | 2 |
Standard features for your comfort
- Low noise propeller design
- Pilot interface: single switch controls pylon extension and doors
- Choice of dual-battery configuration or single-battery configuration
- Automatic centring of propeller after shutdown
- Pilot interface: One switch controls pylon extension and doors
- Engine bay door opening/closing with control sequencing to close the doors for both the retracted and extended positions of the pylon.
UNMATCHED
PERFORMANCE
The RES provides very competitive performance with good power-to-weight
ratios.
The system is design for maximum flexibility and carefully compromised to
allow contest pilots the possibility of a low minimum wing loading, and for the
leisure pilot to have self-launch options at reasonable high wing loadings.
The multiple battery configuration provides unmatched wing loading flexibility
Performance
| Sustain performance - single battery | SI | IMP |
|---|---|---|
| Reference Mass | 460 kg | 1014 lbs |
| Climb rate at MP (25 kW for 4 min) | 2.0 m/s | 394 ft/min |
| Climb rate at MCP (12.5 kW) | 0.8 m/s | 157 ft/min |
| Max altitude gain (approx.) | +/- 900 m | 2953 ft |
| Max sustained range in 18m (approx.) | +/- 81 km | 50 mi |
| Sustain performance - dual battery | SI | IMP |
|---|---|---|
| Reference Mass | 480 kg | 1058 lbs |
| Max continuous power | 25 kW | 33.5 hp |
| Rate of climb at MCP | +/- 2.4 m/s | 472 ft/min |
| Altitude gain | +/-2000 m | 6562 ft |
| Sustained ranged | +/- 157 km | 98 mi |
| Take off performance - dual battery | SI | IMP |
|---|---|---|
| Max aircraft take-off mass | 575 kg | 1268 lbs |
| Climb rate at Maximum Power (40 kW for 1 min) | +/- 3.0 m/s | 591 ft/min |
| Climb rate at Max Continuous Power (25 kW) | +/-1.7 m | 335 ft/min |
| Take-off distance hard surface, 15m obstacle | +/- 430 m | 1410 ft |
| Peak power to clear 15m obstacle | 40 kW for 1min | 40 kW for 1min |
| Energy used to climb 500m (1640 ft) | 2.1 kWh | 2.1 kWh |
| Altitude gain | +/- 1700 m | 5577 ft |
| Sustained range after self launch | +/- 120 km | 75 mi |
Standard Performance Features
- Two-blade carbon-fibre 1.2 m [3.94 ft] diameter propeller designed to optimally
match the battery/controller/motor specifications. - High volt system for reduced current flow and increased efficiency
Optional Performance Features
- Second battery pack option for increased sustaining range or self-launch capabilities
UNCOMPROMISED
SAFETY
JS safety is not negotiable. Operating the RES system gives you the in-control-feeling combined with highly desirable man-machine-interface characteristics.
For safety reasons the two batteries weighing 25 kg each are located in the fuselage, and are removable for safe charging. The novelty of this design is that glider can be
flown with the batteries removed, or with one or both batteries installed.
Standard Safety Features
- Removable batteries for our-of-sailplanes charging
- Automatic battery power connections
- Electrical (430 VDC) isolation monitoring
- Battery, motor and controller temperature monitoring
- Battery internal relay-safe handling, isolating high voltage from terminals
- Internal Current Sensor with Internal Fuses
- Independent fire warning (heat detection) system
MAGNIFICENT
DESIGN
Elon Musk turned the car industry on its head. Who would think a few years back that the most luxury sedan would leave a Porsche behind in a drag race… and do this
in silence with style….
Battery driven vehicles took the world by storm, and the general aviation is slowly catching up. No fumes of fuel, no oil leaks, no vibration, no engine noise, no breaking belts, no starter button.. This all sounds extremely attractive… but where is the catch?
Clearly the energy density is not nearly as good as their petroleum counterpart and therefore battery installations are still heavy for the performance they offer, and they are not as yet well priced. The risk associated with battery fires is a reason for concern, and EASA is actively working on improved special conditions to ensure safe designs – don’t underestimate manufacturers headaches when it comes to certification of systems with large LiPo batteries
Well-known aircraft engine producer, SOLO Aircraft Engines, was the major inspiration behind the retractable electrical propulsion system. SOLO used the JS3 fuselage to model their sustainer design in the “smallest possible modern fuselage”.
JS and SOLO studied the maximum performance of the system and realized self-launching may just be possible. The concept of having not only a sustainer, but also a
limited self-launcher with removable batteries is very exciting.
