RD-701 tripropellant rocket engine

Michel Van

Michel Van

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MASK was a Shuttle program in Soviet union
it had to use a An-225 how carry the Orbiter with Fuel tank, to launch at 8 km high

the Orbiter Glushko RD-701 rocket engine are uniquely
they use in begin oxygen/kerosene later the engine switch on oxygen/hydrogen

Are there any Information how this switch had to work ?
The information are contradictory
some say that engine simply used the warm kerosine feed-line for deep cold hydrogen
but this is very problematic because the turbo-pump is design for kerosine and all remaining kerosine would freeze to solid, destroying the engine
Other claim that the engine burn oxygen/hydrogen from the begin and the kerosine is add for trust increase

so how had Glushko solve this problem ?
 
Michel,

have you checked the information at yoonc.tistory.com/attachment/ik11.pdf? Figure 31 shows a cycle schematic with separate feedlines.

Martin
 
martinbayer said:
Michel,

have you checked the information at yoonc.tistory.com/attachment/ik11.pdf? Figure 31 schows a cycle schematic with separate feedlines.

Martin
Click to expand...

No, this PDF is unknown to me !
many THX for Link, Martin

so the Mystery is solve
the RD-701 was 5 Turbo pumps ! powered by two preburner (oxygen/kerosene)
kerosine and Hydrogen have apart feed-line into the two combustion camber
already from at ignition Hydrogen is used to cool the two combustion camber
 
A tri-propellant engine delivers max thrust (lift-off/initial acceleration at max weight) on LOX/kerosene and max Isp on LOX/LH2. For the MAKS spaceplane, the reduced motor size and weight and lower tankage volume more than compensated for the reduced Isp.
 
LowObservable said:
A tri-propellant engine delivers max thrust (lift-off/initial acceleration at max weight) on LOX/kerosene and max Isp on LOX/LH2. For the MAKS spaceplane, the reduced motor size and weight and lower tankage volume more than compensated for the reduced Isp.
Click to expand...
I'm surprised that we haven't seen any more tripropellant designs. Kerolox with what amounts to a hydrogen afterburner.
 
Scott Kenny said:
I'm surprised that we haven't seen any more tripropellant designs. Kerolox with what amounts to a hydrogen afterburner.
Click to expand...
That's not quite what is happening. The RD-701 can, in some ways, be thought of as two conjoined engines. The hydrogen side is always providing coolant for the chamber and throat, while the kero side is linked to the oxygen turbopumps, specifically, the kerosene high pressure pump and the oxygen high pressure pump are co-axial and thus driven by the same preburner.. I'd note that the pumps themselves are driven by exhaust gases from the oxygen pre-burners, both of which use kerosene as the fuel. No hydrogen and the chamber probably overheats quickly. No kerosene, and the pumps don't really run.
 
TimothyC said:
That's not quite what is happening. The RD-701 can, in some ways, be thought of as two conjoined engines. The hydrogen side is always providing coolant for the chamber and throat, while the kero side is linked to the oxygen turbopumps, specifically, the kerosene high pressure pump and the oxygen high pressure pump are co-axial and thus driven by the same preburner.. I'd note that the pumps themselves are driven by exhaust gases from the oxygen pre-burners, both of which use kerosene as the fuel. No hydrogen and the chamber probably overheats quickly. No kerosene, and the pumps don't really run.
Click to expand...
I was under the impression that the RD-701 eventually stopped burning Kerosene entirely, once it got out of the atmosphere, but that's fine.

What I meant by a hydrogen afterburner is that it's two separate fuel injector sets, and you can throttle the two independently of each other.
 

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