“РД-701: A Rocket Engine Too Beautiful For This World” (Tripropellant & РД-701)

[Skye]

The РД-701 (RD-701) was never built, never fired, and never flown, but it was a concept for a tripropellant (LH2 / RP-1 / LOX) rocket engine by the Soviets, for use on an air-launched, (kinda) SSTO, mini-shuttle: МАКС (MAKS, Multipurpose Aerospace System).

Here is a video by Alexander The Ok. He makes incredible, long analysis videos on all sorts of spaceflight & engineering topics.



And here are some wiki articles.

https://en.m.wikipedia.org/wiki/RD-701

https://en.m.wikipedia.org/wiki/MAKS_(spacecraft)

[Crispy]

Big thumbs up for Alexander the OK. Great videos.

[Skye]

Absolutely 

[InterestedEngineer]

The РД-701 (RD-701) was never built, never fired, and never flown, but it was a concept for a tripropellant (LH2 / RP-1 / LOX) rocket engine by the Soviets, for use on an air-launched, (kinda) SSTO, mini-shuttle: МАКС (MAKS, Multipurpose Aerospace System).

Here is a video by Alexander The Ok. He makes incredible, long analysis videos on all sorts of spaceflight & engineering topics.



And here are some wiki articles.

https://en.m.wikipedia.org/wiki/RD-701

https://en.m.wikipedia.org/wiki/MAKS_(spacecraft)

The fuel tank design would be interesting.  Try converting the kg/sec of each propellant into cm^3 per second of each propellant, and come up with the size of the tanks involved.  Consider that LH2 tanking is far heavier than kerosene tanking.  Then consider that the changeover to almost pure LH2 should happen above about 15 miles, and consider the reasonably brief period of time you need to consume kerosene.

You'll probably converge on a delta-2 design which was pure LH2, and instead of solid rocket side boosters small kerosene tanks.

[edzieba]

You'll probably converge on a delta-2 design which was pure LH2, and instead of solid rocket side boosters small kerosene tanks.

AKA Energia - Hydrolox core with Kerolox strapons (Zenits).