HAWC (Hypersonic Air-breathing Weapon Concept) and HACM (Hypersonic Attack Cruise Missile)

Moose

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IF CDR isn't until 2023 they probably won't fly before 2025.
ARRW, admittedly not the best example given the test failures, concluded CDR in late February 2020 and had it's first flight test in early April 2021. If they're planning to conclude CDR in summer/Q3 2023, assuming it goes well, flight tests starting in Q4 2024 should be very doable.
 

bring_it_on

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IF CDR isn't until 2023 they probably won't fly before 2025.

HACM is likely integrating Air Force US Air force furnished additions, like guidance/seekers, or warhead into the baseline HAWC designed systems. This is why they start in Q3 FY-22 and finish the CDR 12-months later, with pre CDR activities probably having happened concurrent to HAWC as part of other investments. Perhaps they added scope to HAWC and required both performers to finish PDR on a follow on AF weapon.

That said, given a four year developmental timeline, you are looking at around 2026 as a best guess on when the AF may wish to field the weapon. We will know more details in the next budget but my guess would be an EOC of roughly 2025-2027 and I think I mentioned that in one of the tweets in that thread as well.
 
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bring_it_on

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IF CDR isn't until 2023 they probably won't fly before 2025.
ARRW, admittedly not the best example given the test failures, concluded CDR in late February 2020 and had it's first flight test in early April 2021. If they're planning to conclude CDR in summer/Q3 2023, assuming it goes well, flight tests starting in Q4 2024 should be very doable.

ARRW ran concurrent to TBG. TBG flight test activity is planned for FY-21 and into FY-22 while ARRW went into EMD in 2018. HACM on the other hand, launches in the summer of 2022, and follows 8-9 HAWC flight tests (vs 3-4 for TBG IIRC). So at least in its new form (a new start for FY22) it launches only after HAWC finishes and the USAF even calls that out in its budget (HACM is dependent on successful completion of other programs).. So not an apples to apples comparison. But given a general expectation to have the DARPA-AFRL efforts cut EMD down to 4-5 years you can expect that EOC should be achievable in the 2025-2027 timeframe. Completing CDR and going into prototype production followed by flight tests in FY-24, and EOC 12-18 months later.

PS - Can someone change the name of the thread to HACM since that is now a FY-22 new start program for the USAF. I think we're discussing HAWC elsewhere.
 

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Also relevant to this discussion - While HACM officially doesn't start until FY-22, the AF has already moved to award contracts in support of all the work that likely needs to happen pre CDR stage. Lockheed, Raytheon and Boeing were the parties involved. Of these, LM and Raytheon are performing on HAWC so already have flyable scramjet powered systems in flight testing -

 

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IF CDR isn't until 2023 they probably won't fly before 2025.
:) unless there is a spy giving them the blue print of 3M22 Tsirkon

No need for that. They have two mature scramjet engine and weapon concept designs that HAWC has worked on since 2015. At leat 9 HAWC tests are planned before the program finishes in mid 2022 and before HACM launches. What HAWC needed was a transition program that would pick up all that it has worked on and turn that into an operational weapon. This was part of the broader USAF hypersonic portfolio but in FY-22 transitions into a new program distinct from the collective hypersonic prototyping activities (into which all of this has been rolled into). With HACM the USAF has created that and the timing of it beginning as soon as HAWC concludes gives us some indication how how far along HAWC is (at least how far along it was when the FY-22 budget was prepared and presented).

View: https://twitter.com/TheDEWLine/status/1292893994637287425
 

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I’d feel a lot better if either HAWC demonstrator had a publicly successful flight test.

Within the next 8-10 months we should begin to see data emerge on test activities. So far, they have not publicly shared flight test schedules on either TBG or HAWC unlike the ARRW for example where they usually say when they intend on flying (by end of July as in the case of the last failed test). We know from a collection of sources (Missile Defense Agency, DARPA etc) that HAWC flight tests were planned for FY-21 and through at least Q2/Q3 of FY-22. We also know that at least 9 flight tests were planned. For TBG, we know of at least three flight tests planned between FY-21 and FY-22 including 2 this fiscal year and one next year. More testing on integrating a data link into the TBG and in support of a VLS compliant variant are also planned but we don't have timelines on those.

As we go into FY-22 and particularly towards the FY-23 budget release we would have a fairly good idea whether they completed their testing and have moved on or have added additional time due to delays test discoveries etc. Whatever is happening in the background, in flight testing, in ground testing, or in the wind tunnels is promising enough for the USAF to move out of the S&T/R&D world and start a formal program with HACM, and for the Navy to also move ahead with its sub 15 ft scramjet powered cruise missile this year (Navy wants to award Phase 1 contracts by early 2022).
 

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HAWC has been in testing since late last year (at least). But unlike ARRW, they don’t disclose in advance when they plan on going into tests. We should have a better picture towards the end of the year and into the next year's budget release.
 

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I’d feel a lot better if either HAWC demonstrator had a publicly successful flight test.
They haven't got a flight test?
Does anyone know about OASuW II
They intended to fly test HAWC since 2020 but some issue came up
Press reports that a HAWC was inadvertently released and lost during a May captive carry flight were in error, sources said, but the missile was apparently damaged in that test, delaying additional captive carry tests for several months.

Raytheon officials said at the 2019 Paris Air Show that their HAWC might fly by the end of last year, but those predictions proved optimistic.
An attempt by the Defense Advanced Research Projects Agency and the Air Force to fly the first Hypersonic Air-breathing Weapon Concept [HAWC] experimental missile last week failed because of testing snafus, sources report.

DARPA announced in September it had completed captive-carry testing of the two HAWC vehicle types and would be flying at least one by the end of the year. Both Lockheed Martin and Raytheon Technologies have developed HAWC demonstrators, and sources said the Lockheed vehicle was the one being tested. They said last week’s attempt can’t be re-organized by the end of December.

“This is not about a design issue,” said a source familiar with the program. “This is dumb mistakes.”

 

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All we know from the FY-21 budget is that they still plan on completing all flight testing by FY-22. From the AF's request for HACM, we can deduce that DARPA still plans to do this by around mid 2022 (calendar year) or close to Q3 of FY-22. So that's roughly nine flight tests between 2021 and first half of 2022. We won't know how they did against those targets unless more information is made public, or we contrast this to what they publish in the next budget (which should not have a section on HAWC since it would have been completed if they stick to the timeline they presented in this year's budget). On the flip side, apparently the USAF and USN have seen enough to move these efforts further along - the USAF actually spinning this into a weapons program, and the Navy wanting to rapidly prototype a weapon and demonstrate it by early-mid 2026.
 
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So what's the approximate range estimations if it has a JASSM-like footprint?
 

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So what's the approximate range estimations if it has a JASSM-like footprint?

Difficult to tell. I'd assume that it should have a 400-500 km of powered flight (200-300 seconds) but then it could cover a lot more distance post scramjet shut off so yes it is entirely possible that HACM could have very similar to JASSM - ER like performance.
 

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Difficult to tell. I'd assume that it should have a 400-500 km of powered flight (200-300 seconds) but then it could cover a lot more distance post scramjet shut off so yes it is entirely possible that HACM could have very similar to JASSM - ER like performance.
I guess it really comes down to the lift to drag ratio.
 

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That and operating altitude and a bunch of other factors. Safe to assume a 500-1000 km range for this depending on what you want the velocity at impact to be.
 

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X-51 had no warhead, but then again the 3D printed engines are supposed to be half the weight, so it could balance out. I don’t think we know enough to really estimate accurately. Also HAWC is just the demonstrator, not a weapons program, so it probably lacks a warhead as well.
 

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There is that quote that I don't quite understand:
The engine “kicked on” seconds after being released from an aircraft, which DARPA and the Air Force declined to identify, although DARPA expressed appreciation to “Navy flight test personnel.” The Navy has been conducting hypersonic missile research with F/A-18 aircraft.
How can a small scramjet accelerates beyond Mach 5 without a booster when it was just launched from a platform that everybody want you to believe was subsonic...
Either that thing has a tremendous over dimensioned engine (scramjet should just be there to sustain the hypersonic portion of the flight or accelerate an already high and fast vehicle) that is also good as a ramjet... or there is something to fish b/w the lines :)

 
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Maybe booster burn phase is short? They are mentioning booster in text. Or solid fuel rocket motor integrated with hypersonic engine like on Kub missiles?
 

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The vehicle had a booster that separated. The press release mentions that. Even on the X-51, the boosted part of the flight was around 30 seconds so even if they kept that then it would qualify for engine on "seconds after" vehicle launch from the aircraft.

The X-51 wasn't very optimized for a weapon so it is probably possible to have HACM/HAWC being of equal or smaller overall size yet still meet similar range requirement even with a seeker and warhead. The Navy's screaming arrow dimensions can serve as one possible guide though we know from official Navy budgets that the current HAWC is 20 ft long vs 25 ft length of the X-51.
 

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For HAWC, yes it is approximately 20 ft cruiser and the booster all included. We know this because Navy has said that to be able to use HAWC on its AC's it needs to shrink its length down by about 25% for it to fit on elevators. 15 ft is just about the max you can get on an AC weapons elevator. X-51 featured a 14 ft cruiser and 25 ft. overall.
 

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For HAWC, yes it is approximately 20 ft cruiser and the booster all included. We know this because Navy has said that to be able to use HAWC on its AC's it needs to shrink its length down by about 25% for it to fit on elevators. 15 ft is just about the max you can get on an AC weapons elevator. X-51 featured a 14 ft cruiser and 25 ft. overall.
It would have to either be small or almost demand an integral booster (or both). ASALM would fit the bill but it was "only" Mach 4 (Mach 5.4 in tests). Was apparently about 14 feet long. A shame DARPA quailed at the thought of developing LRASM-B. They'd be ahead of the game by now.

 

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@sferrin what was a Sprint booster able to accelerate to although I’m not suggesting such a booster would used for this application.
 

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For HAWC, yes it is approximately 20 ft cruiser and the booster all included. We know this because Navy has said that to be able to use HAWC on its AC's it needs to shrink its length down by about 25% for it to fit on elevators. 15 ft is just about the max you can get on an AC weapons elevator. X-51 featured a 14 ft cruiser and 25 ft. overall.

That would put the demonstrator pretty close to AGM-86 length. It would be a hell of a thing if a B-52 could carry 20 Mach 5 missiles with a several hundred kilometer range. I believe X-51 only had 200+ seconds of flight time and I assume the drag at those speeds rapidly decelerate the vehicle. There is no glide range unless you don’t mind being largely subsonic post burn out.
 

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No exactly.
How do you compensate drag when an engine is lost in a single engine a/c? You nose down. The component that compensate for the loss of thrust (power) is the gravity component time your speed.
Intuitively, it's easy to see that the more speed you have, the greater the vertical component. Hence with a smaller angle of nose down, you can compensate for the drag.

Obviously, speed, temperature and altitude will influence your total drag but this principle remains true and somewhat balanced at the regime of flight discussed here.

With a shallow dive, you can compensate over a long distance for the loss of engine power and glide at a smoothly decreasing speed. Only the change of density will affect your drag, aggravating your angle of descent until not sustainable.

It is essential to remember that those vehicles have a very small drag (that's why they are so fast) but also have a high density, hence their favorable drag Vs weight ratio in the glide phase.

This is the principle of a boost glide hypersonic vehicle, by the way.
 
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bring_it_on

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For HAWC, yes it is approximately 20 ft cruiser and the booster all included. We know this because Navy has said that to be able to use HAWC on its AC's it needs to shrink its length down by about 25% for it to fit on elevators. 15 ft is just about the max you can get on an AC weapons elevator. X-51 featured a 14 ft cruiser and 25 ft. overall.

believe X-51 only had 200+ seconds of flight time and I assume the drag at those speeds rapidly decelerate the vehicle. There is no glide range unless you don’t mind being largely subsonic post burn out.

The X-51 had 265 pounds of JP-7 which was enough for 240 seconds of scramjet on time. To this you add the booster run time of 35 seconds, most of which should be high supersonic or near hypersonic. There was a small gap between when the booster separated and the scramjet lit (when the vehicle was accelerating). All in you are looking at about 450-500 km of powered flight (including booster on time). Here I assumed a Mach 5.5 top cruise speed. Get to Mach 6 and you'll exceed 500 km. All in, the X-51 was expected to splash down some 740 km from launch point given that it was expected to cruise at a fairly high altitude. Now how much have they improved on the the X-51's scramjet engine given learnings from that program and 10-15 years that have elapsed between now and then? That remains to be seen but some efficiency claims from Northrop have hinted at some fairly dramatic improvements over previous gen scramjets. For now, pretty safe to assume that all out range should be in the same ballpark as a JASSM-ER though slightly less if you want a very high speed at impact (which may not be the requirement for all targets as some targets may only want prompt strike but not the survivability of very high speed).

My expectation from HAWC/HACM is a 300-second (original X-51 target?) scramjet run time at Mach 6 for a total powered (booster+scramjet) flight exceeding 600 km. This should give them a 500 mile cruise missile so roughly the same range as a JASSM-ER but a fraction of its time to target.
 
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No exactly.
How do you compensate drag when an engine is lost in a single engine a/c? You nose down. The component that compensate for the loss of thrust (power) is the gravity time your speed.
When to go “nose down” depends on what the velocity is when the engine quits. If it’s greater than best glide speed, then pull up, convert KE to PE, capture best glide AOA and maintain best glide speed is the way to go, but that’s not something you’d want a student pilot to practice. Below, push, capture, glide. FWIW my test pilot and I had to do the latter over Iraq summer of 2006 when the engine chip detector light when off on the engine gearbox.

Optimum for a hypersonic cruise missile would feature some blend of range vs endgame energy
 

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