Reaction Engines Tests Critical Pre-Cooler at Mach 3.3 Conditions

Reaction Engines is working towards air-breathing space planes and hypersonic airplanes. They have successfully tested their critical pre-cooler technology at the temperature conditions it would experience at 3.3 times the speed of sound. The pre-cooler quickly drops the temperature of the air so that the engines for a space plane or hypersonic vehicle would not need to wait for new materials to be developed. This is the key element of the revolutionary SABRE™ air-breathing rocket engine successfully passes the first phase of high-temperature testing. Precooler technology will enable a wide variety of high-speed flight and advanced propulsion systems. Reaction Engines’ precooler heat exchanger successfully achieved all test objectives in the first phase of high-temperature testing designed to directly replicate supersonic flight conditions and future tests are planned at even higher temperatures. The ground-based tests saw Reaction Engines’ unique precooler successfully quench the 420°C (~788°F) intake airflow in less than 1/20th of a second. The intake temperature replicates thermal conditions corresponding to Mach 3.3 flight, or over three times the speed of sound. Mach 3.3 matches the speed record of the SR-71 Blackbird aircraft, the world’s fastest jet-engine powered aircraft produced to date and is over 50% faster than the cruising speed of Concorde. In the recent tests, the compact precooler achieved all test objectives and achieved 1.5 MW of heat transfer, the equivalent to the energy demand of 1,000 homes; successfully cooling incoming air from a temperature at which hot steel starts to glow. The tests are the first phase in an extensive test programme which will see the precooler test article (HTX) exposed to high-temperature airflow conditions in excess of the 1,000°C (~1800°F) expected during Mach 5 hypersonic flight.

The significant testing milestone occurred at Reaction Engines’ recently commissioned TF2 test facility located at the Colorado Air and Space Port, US. The TF2 test facility has been constructed by Reaction Engines to undertake ground based ‘hot’ testing of its precooler technology. The technology has already passed an extensive range of tests in the UK where its performance was fully validated at ambient air temperatures.

Commenting, Mark Thomas, Chief Executive, Reaction Engines, said:

“This is a hugely significant milestone which has seen Reaction Engines’ proprietary precooler technology achieve unparalleled heat transfer performance. The HTX test article met all test objectives and the successful initial tests highlight how our precooler delivers world-leading heat transfer capabilities at low weight and compact size. This provides an important validation of our heat exchanger and thermal management technology portfolio which has application across emerging areas such as very high-speed flight, hybrid electric aviation and integrated vehicle thermal management.”

To replicate the conditions the precooler will experience at hypersonic speeds, the TF2 test facility uses a General Electric J79 turbojet engine formerly used in a McDonnell Douglas F-4 Phantom aircraft to provide high-temperature airflow. Engineers at Reaction Engines’ Culham headquarters constructed the HTX precooler test article and after initial testing it was shipped to Colorado at the end of 2018, and ‘hot’ tests commenced in early March 2019.

19 thoughts on “Reaction Engines Tests Critical Pre-Cooler at Mach 3.3 Conditions”

  1. Flying on a Starship is going to require medical tests, people have brain aneurysms on roller-coasters. Using a Starship for point-to-point travel, where could that go wrong?

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  2. I do not really see the BFR/Starshgip as a good option for commercial point to point travel. The SABRE is probably a better option for those purposes. Building a business class 100 seat aircraft for long-haul international routes could be commercially viable if they can get it to be reliable over enough flight hours in between overhauls.

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  3. the intended purpose of the BFR is off planet travel, I’d say at least half of its systems are designed for beyond earth orbit, its not even going to be very good at delivering satellites due to the way the upper stage is built.

    The lower stage BFR booster is interesting but I think most people won’t want to undergo the G load and the extra preperations for high sub-orbital transit. a plane should be fairly easy to stay beneath any satellite or debris risk (assuming this whole SABRE concept comes together and isn’t just one of many promising projects that gets shelved.

    So my money is that BFR remains a spaceship and this will remain a people hauler. no real threat exists to either of their primary domains from each other.

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  4. The cooler would have to be designed to purpose. The air might pass through more layers of tubes. If they could show a mixed mode engine in operation, that would be something. I don’t think there’s ever been one, unless you count afterburners.

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  5. Turbomachinery does not scale down well, because of shaft speed increase, and increases of leakage around the blade disks. They might not be able to scale down by 10. Maybe to the smallest commercial turbojet available, could be used as a core, something like a small business jet would use.

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  6. That’s an good point, it may be on their road map after static testing of their prototype. But pulling in my decades old steam ship experience, I have to ask does their technology scale down? Heat exchangers in my experience rely on surface area for transfer, as you get smaller, you quickly lose capacity. You can make it more efficient by running a cooling medium in the opposite direction of the fluid you are trying to cool, but it still relies on transfer area.

    Assuming they haven’t figured out a brilliant way around that, would a small scale test demonstrate the amount of cooling they need to achieve for their design goal?

    Of course, I have no knowledge of REL’s technology, so it may not be a concern.

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  7. Most barbeques use propane, at least in the US. If you mean piped natural gas, the same as used in kitchen stoves, I imagine some people are set up for that, but most of the ones I have seen are mobile and run on propane. Mobile means you can take them out of the weather.

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  8. I wonder why reaction engines does not do testing with small scale free flying drones. They would lose some hardware, but they need practice making it anyway. A single engine drone at say 1/10 scale would attract a lot of attention from prospective buyers. Then there’s all that could be learned. A test model can only be a failure if nothing is learned.
    Models could only increase the chances of a full scale engine performing well. They need to do something, or their technology will be left on the wayside anyway.

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  9. Eh, probably not. It takes a certain amount of time for the heat to penetrate and cook the interior, and these engine firings don’t last long.

    Maybe bbq on a stick. That cooks quick. But even then I think you’d need to be closer than the fence line.

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  10. Seriously, though – if REL’s plans take off – and I hope they do, then what threat could they pose to Musk’s Point-to-Point travel scheme for BFR/Starship?

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  11. Because those videos are cool?

    Hrm, actually, I wonder if you could flash roast some chickens by mounting them on a spit just outside the Starhopper fenceline. It’s just LOx and CH4, and CH4 is basically natural gas for fixed BBQ rigs anyways…

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  12. REL is very open to licensing their microtube heat exchanger technology for industrial HX purposes, but it’s meant for more extreme conditions than the back of your kitchen. Better off looking at some of the newer refrigerator technologies, especially the solid state ones.

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