Joby S4 eVTOLJoby S4 eVTOL parked
FieldValue
Aircraft NameJoby S4 (JAS4-1)
Aircraft TypePassenger eVTOL (powered-lift) with six tilting propellers
Number of Propellers6 (five-bladed)
Diameter of Propellers≈ 2.9 m (≈ 9.5 ft) each
Powerplant6 electric motors (dual-wound) driving the tilt props
Energy SourceLithium-ion battery packs
Aircraft Weight (empty)~4,300 lb (≈1,950 kg)
Maximum Takeoff Weight4,800 lb (FAA max gross)
Payload~1,000 lb (≈453 kg)
Range~100 miles (≈161 km) including reserves

Sources & notes:

  • Vertical Flight Society’s eVTOL.news pages summarize the production-prototype S4: six tilt-props, dual-wound motors, batteries; and list ~4,300 lb empty, ~1,000 lb payload, ~5,300 lb “approximate” MTOW, and ~100 mi range incl. reserves. I’ve used their empty weight, payload, and range figures. eVTOL News
  • FAA special-class airworthiness criteria for the Joby JAS4-1 specify maximum gross takeoff weight 4,800 lb; I’ve used this as the MTOW since it’s the authoritative regulatory figure. Federal Register
  • Propeller diameter is not listed on Joby’s site/FAA criteria; multiple technical references cite ~2.9 m (9.5 ft) per rotor (consistent with early internal/technical slides). Treat as best-available public estimate. catalogs.glenair.com+2Scribd+2

Unique / Distinctive Features of Joby S4 (JAS4-1)

FeatureDescription & Why It’s Unique
Tilt-rotor / tilt-prop configuration with mixed placementThe S4 has six tilting electric propellers: four mounted on the wings, two on its V-tail. Some propellers tilt via the motor nacelle, others via linkages. This mixed tilt mechanism allows more optimal transition between hover and forward flight.
Hybrid characteristics: rotorcraft + winged airplaneIt operates like a rotorcraft for vertical take-off/landing, and like a fixed-wing airplane in cruise, with the wings and control surfaces (ailerons/flaps) contributing to lift. This gives better efficiency in forward flight vs pure VTOL designs.
High redundancy & safety featuresDual-wound motors, dual redundant inverters, multiple battery packs, etc., plus redundancy in critical subsystems. It also has to meet special airworthiness criteria under FAA “powered-lift” category. This ensures higher safety margins.
Noise reduction / low acoustic signatureIn cruise, noise is very low (~45 dBA in one estimate), claimed to be much quieter than helicopters. Useful for urban operations with strict limits on noise.
Simplified Vehicle Operations (SVO)Designed to reduce pilot workload by integrating flight control systems, smoothing transitions between vertical and forward flight, making operations simpler. This is important for safety, certification, and operational cost.
High performance in speed + range for eVTOLWith cruise speeds up to ~200 mph (≈322 km/h) and range up to ~100 miles (~160-150 sm depending on source), it pushes higher than many VTOL designs in the speed-range trade-off.
Certification under “special class / powered-lift” categoryJoby’s JAS4-1 is being certified under FAA’s special airworthiness criteria for a powered-lift aircraft — defining rules combining airplane & rotorcraft standards. That’s fairly novel.
Composite materials, lightweight designMany components, including propellers and structure, are composite materials, optimizing weight vs strength. Combined with advanced battery tech that has relatively high Wh/kg (energy density) helps performance.
Large windows / cabin experienceThe design includes large windows so passengers get panoramic views, improving user experience, which is an important consideration for air-taxi style operations.

One thought on “Joby S4 (JAS4-1) Data”

Leave a Reply

Your email address will not be published. Required fields are marked *