Overview
The Phoenix-1B Mk II is a single-stage unguided ballistic sounding rocket powered by the PV-3 hybrid rocket motor. The primary mission of the P-1B Mk II is to reach an apogee altitude of 35 km. As the Mk II of the P-1B series, it incorporates a number of improvements upon its predecessor including the use of aluminium additive in the fuel grain to reduce the nominal O/F ratio and a composite oxidiser tank to reduce the vehicle inert mass.
The vehicle is 4.92 m long with a diameter of 0.17 m at the tank and 0.164 m at the motor. It has an inert mass of 47 kg, a propellant mass of 41 kg, and a total mass of 88 kg. The motor uses 34 kg of nitrous oxide as the oxidiser and 7.05 kg of paraffin wax with aluminium additive at 20% for the fuel. A metallised fuel grain has the potential to increase the specific impulse and reduce the O/F ratio, thus reducing vehicle weight.
PV-3 Hybrid Rocket Motor
The PV-3 hybrid rocket motor has a nominal thrust and chamber pressure of 7250 N and 40 bar respectively with a burn time of 14.2 s. It operates via blowdown feed system whereby the oxidiser tank ullage is supercharged with helium to 65 bar to drive the oxidiser into the motor.
1 – Injector bulkhead, 2 – Injector plate, 3 – Bulkhead insulation, 4 – Pre-combustion chamber insert, 5 – Fuel grain, 6 – Thermal liner, 7 – Chamber casing, 8 – Post-combustion chamber insert, 9 – Nozzle.
Oxidiser Tank
A composite oxidiser tank was designed to be used on the P-1B Mk II to reduce vehicle inert mass compared to the P-1B Mk I, which utilized an aluminium tank. The tank was manufactured using 4-axis filament winding machine using a T800 carbon/epoxy composite. The tank liner was formed using a uPVC pipe in conjunction with aluminium bulkheads due to nitrous oxide compatibility constraints and material availability. The tank was designed for a MEOP of 80 bar with a minimum safety factor of 2.25 for all loading conditions. The bulkheads are fixed using stainless steel locator pins and has a dual EPDM O-ring seal.
1 – Top bulkhead, 2 – Bottom bulkhead, 3 – PVC liner, 4 – Locator pins, 5 – Dual O-ring seal.
Technical Specifications
| Fuel | Paraffin wax | |
| Oxidiser | Nitrous oxide | |
| Fuel additive | Aluminium (20%) | |
| O/F ratio | 5.4 | |
| Thrust | 7250 N | |
| Tank pressure | 65 bar | |
| Chamber pressure | 40 bar | |
| Burn time | 14.2 s | |
| Total impulse | 76 537 Ns | |
| Specific impulse | 192 s |
| Design apogee | 35 km | |
| Vehicle mass | 88 kg | |
| Vehicle length | 4.92 m | |
| Vehicle diameter | 0.17 m | |
| Range | 24.8 km | |
| Max. speed | Mach 2.31 | |
| Max. acceleration | 6.14 g | |
| Flight time | 136 s | |
Testing
Cold flow test
Hot-fire test
Launch test