# DG-S Technical Specification

### Scramjet Subsystem

The Delta-glider is equipped with two scramjet engines located at the underside of the fuselage which can be used during the atmospheric phase of Earth ascents/descents to preserve propellant for the primary engine system.

To provide sufficient compression of the airstream in the diffusor, the scramjets should only be operated at velocities M > 3.0. Takeoff and initial climb phase therefore require the use of the DG main engines.

Parameter | Flight model
--- | ---
easy | complex
Intake area | 2 x 1.0 m2 | 2 x 1.0 m2
Burner temperature limit | 3500 K | 3200 K
Propellant | Hydrocarbon[1] | Hydrocarbon[2]
Fuel heating value (in air) | 3.5·108J/kg | 2.0·108J/kg
Fuel pump capacity | 2.0 kg/s (max) | 3.0 kg/s (max)
Thrust rating (v=Mach 4, alt=10km) | 390 kN per engine | 340 kN per engine
TSFC (v=Mach 4, alt=10km) | 0.0051 kg kN-1 s-1 | 0.0088 kg kN-1 s-1
Fuel capacity | 4.0·103 kg[3] 10.4·103 kg[4] | 4.0·103 kg[3] 10.4·103 kg[4]
Operational speed | Mach 3.0 ≤ v ≤ Mach 7.3 | Mach 3.0 ≤ v ≤ Mach 7.3
Operational altitude | 10 km ≤ h ≤ 40 km | 10 km ≤ h ≤ 40 km
Sustained speed (level flight) | Mach 4.3 (alt=10km) Mach 7.5 (alt=20km) | Mach 3.9 (alt=10km) Mach 7.3 (alt=20km)

[1]) magically enhanced
[2]) enhanced
[3]) configuration A
[4]) configuration B

Fig. 1: DG scramjet TSFC vs. Mach number at ambient density 0.43 kg/m3 and ambient temperature 225 K (corresponding to altitude 10 km in standard atmosphere).

Fig. 3: DG scramjet single engine thrust vs. Mach number.