RD-701

RD-701 (РД-701)
Country of origin USSR/Russia
Date late 1980's
Manufacturer Energomash
Successor RD-704
Status Experimental
Liquid-fuel engine
Propellant Mode#1: LOX / LH2&RP-1;
Mode#2: LOX / LH2
Cycle staged combustion
Performance
Thrust (vac.) Mode#1: 900,000 lbf (4 MN)
Mode#2: 357,000 lbf (1.6 MN)
Thrust (SL) Mode#1: 714,000 lbf (3.2 MN)[1]
Chamber pressure Mode#1: 4,351 psi (30 MPa)
Mode#2: 2,176 psi (15 MPa)
Isp (vac.) Mode#1: 415 s
Mode#2: 460 s
Isp (SL) Mode#1: 330 s
Dimensions
Diameter 94 in (2,400 mm) (1 nozzle)
Dry weight 4,240 lb (1,923 kg)[1]

RD-701 (Russian: Раке́тный дви́гатель 701, Rocket Engine 701) - liquid-fuel rocket engine developed by Energomash, Russia. It was proposed to propel the reusable MAKS space plane before cancellation of this project. The RD-701 is a tripropellant engine that uses staged combustion cycle afterburning of oxidizer-rich hot turbine gas. This engine has two modes. Mode #1 uses three components: LOX as an oxidizer and a fuel mixture of RP-1 / LH2 which is applied for near earth surface conditions. Mode #2 also uses LOX, with LH2 as fuel in vacuum where atmospheric influence is negligible.

The use of less dense fuel components at maximum efficiency conditions allows minimizing the volume of fuel tanks and subsequently their mass down to 30%. As of 2009 the engine is characterized by highest value of pressure, 300 bar, ever used in combustion chamber of rocket engines when running in Mode #1 with mixture of fuel components. The RD-701 became the base model for RD-704 with one combustion chamber.

Specifications

Two-chamber RD-701 has two modes. The first one uses three components: RP-1 (mass flow — 73.7 kg/s), LH2 (mass flow — 29.5 kg/s) and LOX (mass flow — 388.4 kg/s). This mode is applied in lower atmosphere to minimize fuel tanks volume. The total thrust for altitude 10 km is 2х1,890.2 KN and exhaust velocity is 3,845 m/s, giving a specific impulse of 392s.

The second mode uses just two components: LH2 (mass flow — 24.7 kg/s) and LOX (mass flow — 148.5 kg/s). This mode applied for near space conditions and gives thrust 2х784.5 KN, specific impulse — 4,532 m/s.

The mixing block of the main combustion chamber has three groups of injectors, one for each of the three available components. When running in Mode #2 the engine doesn't use the kerosene group. The engine uses regenerative cooling by liquid hydrogen.

RD-704

The RD-704 is a smaller version of basic engine and uses the same components and scheme of work but with one preburner, turbopump, combustion chamber and nozzle.

See also

References

  1. 1 2 Engines of MAKS: RD-701.
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