Hypersonic plane startup, Hermeus, plans to make a plane faster than the SR-71 blackbird spy plane. the SR-71 could reach mach 3.3 and fly at 85000 to 100,000 feet in altitude.
Quarterhorse Mk 2 will fly with this precooler-F100 engine combination and be capable of hitting speeds greater than Mach 2.5. The entire Chimera engine, which includes a ramjet, will power Hermeus’ following aircraft, Quarterhorse Mk 3. This aircraft will reach speeds close to Mach 4 and pave the way for future Hermeus aircraft that will fly at hypersonic speeds.
The 2026 Quarterhorse Mk 3 prototype will fly to Mach 3.3 and beyond and get high altitude like the SR-71 then it will have a controlled dive to get towards mach 5 as it switches to the ramjet. The ramjet is not efficient in until speeds are near mach 5. Previous hypersonic designs have involved three engines. Hermeus will only use two engines. They will pre-cool the regular engine to get up to mach 3.3 or more then they use gravity to bridge the inefficient gap to get up to efficient ramjet speeds.
The planned, controlled dive is explained in this video by the technical lead of Hermeus.
Quarterhorse Development Timeline:
Mk 1: The first flyable version of Quarterhorse, Mk 1, is set for flight tests later in 2024. These tests will focus on high-speed takeoffs and landings
Mk 2: Scheduled for 2025, Mk 2 will be powered by a Pratt and Whitney F100 engine, enabling supersonic flight. This version will serve as a precursor to the full hypersonic capabilities planned for future iterations
Mk 3: Expected to be developed by 2026, Mk 3 will incorporate Hermeus’ Chimera II propulsion system, which includes a modified F100 engine. This version aims to achieve speeds faster than Mach 3.3, supporting Defense Department testing.
Getting to Hypersonic Speed
Turbojet Mode: At lower speeds, the Chimera engine operates in turbojet mode, similar to conventional jet engines. This mode is effective up to approximately Mach 2+, where the performance of turbojets starts to decline due to increased air temperature and speed.
Pre-cooler Functionality: To extend the operational range of the turbojet, Chimera incorporates a pre-cooler that reduces the temperature of incoming air. This allows the turbojet to function efficiently to Mach 3 by providing additional performance headroom and could enable operation up to nearly mach 4.
Transition to Ramjet Mode: As the aircraft accelerates to Mach 4, the engine begins to bypass the turbojet, and the ramjet takes over. The ramjet operates by compressing incoming high-speed air without the need for a compressor, mixing it with fuel, and igniting the mixture to produce thrust. This mode is optimal for speeds between Mach 3.5 and Mach 5. This is where the Hermeus drones or jets will be put into a dive.
Testing and Validation: The mode transition has been tested and validated in lab conditions that simulate high-Mach temperatures and pressures, significantly reducing the risks associated with the Quarterhorse’s flight test campaign.
Like Quarterhorse, Darkhorse will be powered by a Hermeus-developed turbine-based combined cycle engine. This version of Chimera is significantly more powerful as it integrates the Pratt & Whitney F100.
Hypersonic aircraft represent a major step change in defense technology, offering unprecedented speed, altitude, and maneuverability. These attributes allow Darkhorse to operate responsively in contested environments.
Halcyon will be a passenger aircraft capable of accelerating 125+ trans-oceanic routes at hypersonic speeds – five times faster than any commercial aircraft today. This will require more powerful engines to be developed. Passengers would not accept crash diving from mach 3.5 to mach 5 to reach their destination.
Hermeus will have to make money with the hypersonic Dark Horse military drones to get the funding for the hypersonic passenger jet engine development.
Mach 5 hypersonic passenger planes will enable 90 minute flights from New York to London.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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It seems to me they are going about this the wrong way. Look how big this is in frontal area. Why? Because they need lots of lift to take off and to land at reasonable speeds. I’m not saying this is easy, but I am saying there are technologies proven that can solve this.
1. oblique wing aircraft
https://en.wikipedia.org/wiki/Oblique_wing
We made one. It worked, had some roll problems at high angles, but it mostly flew well. With modern digital flight controls, this could be controlled. The shock wave would be in the front, so flaps would have to change their function depending on speed. Once again, I think this could be done. So you solve the landing problem with large wings while drastically reducing the areas subject to high heat and drag. They could use full wings to take off and land, slant them to get up to speed and, possibly, at really high altitudes, make them more spread out to have enough lift in ratified air. At high altitude you have little friction so you could go really fast. At low altitude with these you could go not as fast, but much faster than a normal plane due to reduced drag.
2. We built RAM jets in the 1950’s. Surely someone can make one now.
https://en.wikipedia.org/wiki/CIM-10_Bomarc
At high altitudes the air pressure would be less, so less slowing down of the air (air pressure) would be needed even at really high speeds.
3. And why do we still have vertical tails?????? Look at the tail area of vertical and horizontal stabilizers. Ok, but not very useful if going slow and too much drag going fast. A balance. Why not build what is essentially a dragon tail. Have it with a LARGE articulation. When going slow, it bends a lot, as needed, curling up like a scorpions tail.
https://a-z-animals.com/media/2018/09/Scorpion-on-sand.jpg
The actual area would be much larger than a fixed horizontal tail. So going slow, it could have a large force. When going fast, it would not need to displace its position near as much. And the force on it when going slow or fast could be the same but with more defection at low speed, less defection at fast speed. The amount could be set depending on how strong you made the plane’s tail and how fast a turn you wanted. A tapered tail like this would have WAY less drag and possibly less radar reflection. It could also, due to its long tail, I believe, stabilize the plane more. If it yaws, a large force from the tail would straighten it.
I think you’re taking the provided graphics too seriously at this point. Many of the hypersonic aircraft images that currently show up on searches hit shortly after the last Topgun movie and the featured Dark Star (the real star of the movie). They’re all variations of the same design. I know, I got caught up in them. Even found a plastic model that managed to beat the licensed one to market, on Ebay.
Calling it hypersonic is dubious. The hypersonic regime *starts* at Mach 5. It’s like calling something that barely tickles the sound barrier “supersonic” when it’s not really, it’s transsonic.
Mach 5 delineates the point at which things start getting “weirder” and harder to deal with, but by no means are those effects particularly strong yet. At Mach 10 for example, the air molecules split into their constituent atoms which either recombine with each other emitting radiation, or erode the surface of the craft. Your velocity dictates whether this happens with just nitrogen, or oxygen as well (atomic oxygen is one of the most corrosive substances known) and in what proportion. That is a fairly standard consideration to make when designing a hypersonic vehicle, and it isn’t a consideration of this one.
The case of a Mach5 spy plane is dubious. At Mach5 the thing is visible (and audible) from very far, as such speed can be sustained only at high altitude (any satellites with IR sensors will see its heat same as ICBM launch), where air defense systems from 50 years ago can hit it (designed to intercept SRBM and IRBM) with high probability. At Mach5 maneuvering is minimal, so the thing would be able to evade an interceptor missile, would not even be aware of it as shockwave and heat creates all kinds of problems for antennas. The shockwave would be detectable by seismic sensors network, such as ~30-years old nuclear test detection network. And finally the spying part. It can be either RF or optical type, both of which would be severely affected by Mach5 environment.
What does make sense is the case of a long-range strike with nuclear warhead. Cost and reuse become non-issues, the altitude could be low, and the thing can be literally falling apart (remember SpaceX flight) at the end of trajectory. Ablative coating becomes an option, because it is a one-time thing. Question is why bother making Mach5 jet if a rocket could do the same thing – and did: AGM-69 SRAM at Mach3, Sprint at Mach10, and perhaps some things in-between. But government logic is non-intuitive, so making an unnecessary and expensive thing that does what simpler and much cheaper things did 40 years ago may be ‘reasonable’.
In any case, this thing looks very much like a first-strike nuclear delivery vehicle, not a bs magical spy plane. If it comes to that, F-35 with B61-12 could not even take off within range of hypersonic missiles with flight time measured in seconds, and abundant precision-guided ballistic missiles (Iranian, NKorean, Chinese and whoever’s).
Reply to Brett: That makes sense, except any aircraft carrying cryogenic liquids would require a complex and heavy infrastructure. Then again, OX in tanks as a high pressure gas would be much less complicated, or embedded within a permeable membrane. Yeah, I like it.
This is just a thought, I’m not an aerospace engineer (and don’t play one on TV.) But I know something about how fluids work. And air is a fluid. What I understand about hypersonic travel threw the atmosphere is much less about heat (though that’s not a “little” problem, but quite negotiable) it about air, when you move threw it after a certain speed the nature the air and how it affects you does change. Ex: Jump off a diving board from the usual height and you make a splash. Hit water after falling several thousand feet, you have the same kinetic impact of hitting concreate. You’ll make one hell of a splat. From several thousand feet, hitting concreate or water, the affect on you is still the same. Not good.
Moving threw air at hypersonic speeds we see air affecting our aircraft by behaving more like a “paste, or gel”, with turbulent pockets that can act like bombs. Even with early supersonic jets we had to “slow down” the air going into jet engines in one method, “cones” that spread the air volume coming in. (By the way, that’s how most planes fly. The area of a wing is greater on top, then the bottom. When air flows over/under a wing it has to go “further” over the top, that creates lower air pressure. The higher air pressure on the underside of wing, pushes it up.) I’m sorry, most of you know this. I don’t mean to be a prick, it just comes so easy for me… Sorry. But hypersonic air breathing craft are EMENSLEY more difficult to do then supersonic aircraft.
It’s all based on how the nature of air changes when a vehicle moves threw it at hypersonic speeds. Rockets don’t have a problem because they don’t suck in air to use as part of their fuel. Frankly, air does not play well with others when you move fast enough threw it. As I understand it, the smooth transition to/from ramjet mode has been the MAJOR problem in developing reliable hypersonic aircraft. Love if that’s been solved.
Whatever happened to the proposal I heard a while back to spray LOX or liquefied air into the intake of a turbo-jet, both cooling the incoming flow, and allowing operation at higher altitudes? This was an alternate way of operating the turbojet until the scramjet would be efficient.
Perhaps you were remembering MIPCC or LACE perhaps? MIPCC usually dumps water in the intake to cool the air for the compressor and increase massflow. LACE was trying to liquefy intake air to pump into what effectively is a rocket engine, but generally need liquid hydrogen to enable liquification of intake air.
MIPCC was proposed for the F-4X, a fancy pants version of the F-4 fighter