Blue Origin's BE-7 engine

[AS-503]

Agree with meekGee.
The F1 had a traditional gimbal on the top of the thrust chamber.
Another clue is that the photos clearly show the struts that are actuated by the hydraulic ram are connected to the thrust chamber NOT the nozzle.
It it was a nozzle gimbaled design the struts would be on the nozzle.

[sevenperforce]

I feel like the load paths for a virtual gimbal about the nozzle throat would be hella challenging. You're talking about truly immense forces and the natural geometry of the engine already directs those forces up the nozzle and into the combustion chamber axially. Trying to transfer a load into gimbals mounted anywhere other than the chamber...yikes.

[edzieba]

The disadvantage of course is that the throat now has to have the ability to flex.

The diagram is misleading: there is no flex at the throat, the engine gimbals about an axis within the throat, but that just means the powerhead swings about the pivot in the opposite direction to the nozzle. The main impact of this is clearance within the engine bay, and that instead of one propellant feed line translating and rotating and one just rotating (assuming it is routed through a topend gimbal) both feed lines translate and rotate. This is not uncommon for vernier engines (e.g. Atlas, Thor, Soyuz).

[FutureSpaceTourist]

https://twitter.com/blueorigin/status/1803789703004430524

Here’s a BE-7 engine headed into vacuum cell testing in a simulated space-like environment at Air Force Research Laboratory, Edwards Air Force Base, CA. BE-7 generates 10,000 lbf of thrust and powers our Blue Moon MK1 and MK2 lunar landers.

[FutureSpaceTourist]

https://twitter.com/blueorigin/status/1825925995892797800

BE-7 engines power our Blue Moon MK1 and MK2 lunar landers. Grateful to partner with @AFResearchLab at Edwards Air Force Base, CA, where we conduct BE-7 testing in a vacuum cell to simulate a space-like environment. Here’s the team after a successful full-duration test that included ignition.

[Robert_the_Doll]

https://twitter.com/davill/status/1825944824551555290

Here’s another view of a BE-7 in testing. Great to see the team’s progress at Edwards. BE-7 has a novel high-performing dual-flow closed expander cycle. MK1 has one BE-7 engine, and our larger MK2 crewed lander, part of the Artemis effort, is powered by three BE-7s.

[Robert_the_Doll]

https://twitter.com/davill/status/1971697335882469451

BE-7 vacuum test. Engine in flight configuration with flight pumps, tank head start, and spark igniter. We’re currently hot-firing this engine five times a day. Full flow closed expander, specific impulse 460 seconds. Next stop, the Moon.

[Robert_the_Doll]

https://twitter.com/davill/status/1973527019557363723

With rocket engines, boring is good. To that end, please enjoy this 1,030-second (17+ min!) BE-7 engine burn. This test represents the Apogee Raise Maneuver or ARM burn for our Blue Moon Mark 1 Lunar lander, plus margin, the longest burn required by the mission to reach the Moon. You may have noticed that the engine for this test does not have a nozzle. BE‑7 is tested in both vacuum and atmospheric conditions. This test was at  GEEx—our atmospheric test position in West Texas.

[StraumliBlight]

[Tywin]

Is the BE-7 the more efficient hydrolox engine of history?

[PahTo]

Is the BE-7 the more efficient hydrolox engine of history?

I think the RL-10 variant(s) with the extensible nozzle still has (had) the best ISp.  iirc, the newer versions (c and x) are all fixed nozzle but get close due to improvements in material sciences and flow(s).

[Tywin]

Is the BE-7 the more efficient hydrolox engine of history?

I think the RL-10 variant(s) with the extensible nozzle still has (had) the best ISp.  iirc, the newer versions (c and x) are all fixed nozzle but get close due to improvements in material sciences and flow(s).

Do we have a number of ISP?

[catdlr]

Is the BE-7 the more efficient hydrolox engine of history?

I think the RL-10 variant(s) with the extensible nozzle still has (had) the best ISp.  iirc, the newer versions (c and x) are all fixed nozzle but get close due to improvements in material sciences and flow(s).

Funny that it was posted at the same time as your discussion on RL-10.

RL-10
The first liquid-hydrogen rocket engine that was developed in the U.S.
The first successful flight was back in 1963, but a modernized version is still used today for the second stage of Atlas V and Vulcan🚀.

https://twitter.com/SpaceIntel101/status/1979973067691475024

[JEF_300]

Is the BE-7 the more efficient hydrolox engine of history?

I think the RL-10 variant(s) with the extensible nozzle still has (had) the best ISp.  iirc, the newer versions (c and x) are all fixed nozzle but get close due to improvements in material sciences and flow(s).

Do we have a number of ISP?

Dave Limp gave us one in this tweet. 460s
So better than most, but not all, RL10s.

https://x.com/davill/status/1971697335882469451

[PahTo]

Is the BE-7 the more efficient hydrolox engine of history?

I think the RL-10 variant(s) with the extensible nozzle still has (had) the best ISp.  iirc, the newer versions (c and x) are all fixed nozzle but get close due to improvements in material sciences and flow(s).

Do we have a number of ISP?

Dave Limp gave us one in this tweet. 460s

https://x.com/davill/status/1971697335882469451

...and the RL10-B2 with extended nozzle comes in around 465s.

[JEF_300]

Is the BE-7 the more efficient hydrolox engine of history?

I think the RL-10 variant(s) with the extensible nozzle still has (had) the best ISp.  iirc, the newer versions (c and x) are all fixed nozzle but get close due to improvements in material sciences and flow(s).

Do we have a number of ISP?

Dave Limp gave us one in this tweet. 460s

https://x.com/davill/status/1971697335882469451

...and the RL10-B2 with extended nozzle comes in around 465s.

I wouldn't be too confident with the 465s number. I've seen 462s cited just as often.
But yes, the best RL10 is a bit better. Most modern RL10s (Centaur III and Centaur V) are a bit worse, around 453s. I believe the upgraded RL10s planned for Centaur V and the EUS are also at about 460s, so the same.

[spacenut]

Does the BE-7 less expensive than the RL-10?  If so can it replace the RL-10 to cut costs for ULA who uses the RL-10?

[Robert_the_Doll]

Does the BE-7 less expensive than the RL-10?  If so can it replace the RL-10 to cut costs for ULA who uses the RL-10?

1. We do not know what the price for BE-7 is.

2. The thrust of the BE-7 is up to 2.5 times less than than the current models of the RL-10.

3. L3 Harris/Rocketdyne has a deal to produce 116 RL-10C-X engines for Centaur V.

Therefore, it would not be suitable for a number of applications in terms of an upper stage engine that ULA is looking for, and backing out of the deal with Aerojet Rocketdyne could prove more expensive than it would be worth in order to pursue an upgraded version of BE-7 to replace RL-10C-X.