Rotating Detonation Engines

[john smith 19]

Under the contract, RTX will rely heavily on iterative development of performance models which will be anchored by real-world data from incremental system tests. This proven method accelerates learning to provide more certain flight test outcomes, saving both time and cost. Future optional phases of the Gambit program will shift to building hardware to conduct a flight weight free-jet test.

Also proven to boost profits.

And modeling, as Elon shows, makes you learn nothing about how to build these systems in volume.  Which means the unit cost will be insanely high.

You need to build iterate, not model iterate

A fair point and Raytheon are dyed-in-the-wool defence contractors. But note

will be anchored by real-world data from incremental system tests.

This suggests there will be hardware built, data collected and that data used to update the models.

The joker is the complexity of the test stand to simulate the other bits of the engine. One of the SSME test stands had 2000 valves, which in the early 70's would probably only have been partly computer controlled, with the rest being set by hand. 

However as Val Cleaver observed in the early 60's, the best model of an engine is the engine itself. IOW build it complete, build it early and test ASAP, while standing well back of course.

Time will tell if this makes significant progress quickly (like the PDE, which got to flight-test in IIRC < 20 years) or it's going to be more like the SCramjet.

[edzieba]

Remember that SpaceX also does component and subscale testing. Raptor component testing (up to and including powerhead) occurred at Stennis, and an entire sub-scale Raptor engine was developed and fired before the full-size version. They didn't just jump straight to a full-scale engine, years of simulations and component testing occurred first.

[john smith 19]

Remember that SpaceX also does component and subscale testing. Raptor component testing (up to and including powerhead) occurred at Stennis, and an entire sub-scale Raptor engine was developed and fired before the full-size version. They didn't just jump straight to a full-scale engine, years of simulations and component testing occurred first.

Is this post in the right thread?

[Asteroza]

GE ran a dual mode ramjet with a rotating detonation wave combustor?

https://www.flightglobal.com/engines/ge-aerospace-achieves-breakthrough-in-hypersonic-engine-development/156198.article

[InterestedEngineer]

GE ran a dual mode ramjet (DMRJ) using a rotating detonation wave (RDE) combustor?

https://www.flightglobal.com/engines/ge-aerospace-achieves-breakthrough-in-hypersonic-engine-development/156198.article

Cool, an RDW engine in functional prototype form!

I'm curious what the TWR is in theory for a RDW.  A rocket engine is in the 150:1 range, a decent turbofan is about 6:1.  A huge difference, severely limiting the mass of fuel that can be carried.

[FutureSpaceTourist]

[RON_P]

More info on the recent GE breakthrough .
 https://aviationweek.com/aerospace/aircraft-propulsion/rotating-detonation-sparks-ge-path-hypersonic-future

[Asteroza]

More info on the recent GE breakthrough .
 https://aviationweek.com/aerospace/aircraft-propulsion/rotating-detonation-sparks-ge-path-hypersonic-future

Note GE says the rotating detonation wave combustor is in the ramjet part, not the turbine part, and the engine is described as TBCC RD-DMRJ. We don't see much commentary here on rotating detonation wave ramjets here, just RDE rockets or RDE combustors fitted to otherwise conventional gas turbines.


Recent googling pulled up some polish research on a rotary ramjet style engine, combining a supersonic inlet style rotary compressor with a rotating detonation wave combustor on a single disc. See the end of the following literature view.

https://www.mdpi.com/1996-1073/15/24/9353

https://arc.aiaa.org/doi/10.2514/6.2017-1286

Shades of the RamGen rotary ramjet ISCE and friends.

[Asteroza]

Possibly the same video, but the original NASA youtube video

[daveglo]

Possibly the same video, but the original NASA youtube video

Does not look like the same video.  Setup connections have differences.  Nozzle is different.  Runtime is much shorter than the 251 second test run.  But the original video posted is NOT on the MSFC YouTube page.  Hm.

[Asteroza]

Interesting news from china

https://web.archive.org/web/20231229013940/https://www.scmp.com/news/china/science/article/3246361/revolutionary-design-chinese-scientists-invent-most-powerful-detonation-engine-hypersonic-flight

When a RDE goes so fast (above mach 7) that you need to straighten out the rotating wave into a "straight" (oblique?) flow through continuous detonation wave engine.


Additionally

https://web.archive.org/web/20231222165528/https://www.scmp.com/news/china/science/article/3235502/explosive-engine-test-drone-could-propel-china-supersonic-age

Working up to a flight model RDE on a small drone (I think it's the small fist sized object above the wing on the left) (Is that a Su-34 model plane?!?)

[Gliderflyer]

Possibly the same video, but the original NASA youtube video

Does not look like the same video.  Setup connections have differences.  Nozzle is different.  Runtime is much shorter than the 251 second test run.  But the original video posted is NOT on the MSFC YouTube page.  Hm.

The presentation on NTRS has a lot more videos in it (along with other details), they may have gotten it from there.

[john smith 19]

Interesting news from china

https://web.archive.org/web/20231229013940/https://www.scmp.com/news/china/science/article/3246361/revolutionary-design-chinese-scientists-invent-most-powerful-detonation-engine-hypersonic-flight

https://web.archive.org/web/20231222165528/https://www.scmp.com/news/china/science/article/3235502/explosive-engine-test-drone-could-propel-china-supersonic-age

This is great news.

For any US defense companies wanting to shake the tree for more SCramjet money that is. 

Of course the fact that the Chinese appear  to have achieved a flight test of a vehicle in such quick time (when it took the US from 1956 to 2004 for a SCramjet to build an SCramjet whose thrust exceeded its drag) and the RDE can generate thrust from a standing start should be grounds for a Cost/Benefit review of all US SCramjet research.

But that won't happen.

I note the RDE is a cousin of the PDE, which IIRC the USAF were able to engineer into a positive thrust flight test (on a propeller driven plane) within 20 years of it being first discussed. 

Still I did like the model it's supposed to be flying on.

Very pretty.

[sdsds]

Catching up on this thread has been illuminating! Came here due to a single sentence in https://ntrs.nasa.gov/api/citations/20230017880/downloads/Trent%20MACHETE%20SciTech2024%20Manuscript%20v3.pdf

Without RDRE, the vehicle concept is not feasible.

Apparently some mission architecture designers are willing to bet their design on the success of rotating detonation rocket engine development.

[john smith 19]

Catching up on this thread has been illuminating! Came here due to a single sentence in https://ntrs.nasa.gov/api/citations/20230017880/downloads/Trent%20MACHETE%20SciTech2024%20Manuscript%20v3.pdf

Without RDRE, the vehicle concept is not feasible.

Apparently some mission architecture designers are willing to bet their design on the success of rotating detonation rocket engine development.

True.

Venus Aerospace is IIRC one of them. 

[Asteroza]

Venus reporting on their DARPA progress.

https://www.venusaero.com/venus-aerospace-rotating-detonation-rocket-engine-achieves-long-duration-run/



They've added cooling to run longer, so I guess that means previous tests/prototypes were partially or fully uncooled?


Anyways, it might be an artifact of the camera but I thought the exhaust shown has some interesting bits to it.

[Asteroza]

Venus got a hydrogen peroxide RDE drone flying recently

https://www.venusaero.com/venus-aerospace-inaugural-supersonic-drone-flight/

But, it was only a basic drone flight stability test after being air dropped along with one half of the RDE operating. Since the drone doesn't appear to have an intake, I guess the monopropellant hydrogen peroxide is split with a catalyst before entering the RDE to operate as a rocket (with implied oxidizer/fuel sides)?

[Durham Park]

How would you split the gases once generated?
Can the monopropellant be used just as it is in a mixed gas state?

[edzieba]

... "Monopropellant" is the key word there.

[Remes]

Nice inside into the basics, measurement principles and some theoretical work (the paper is also linked):