The X-51a WaveRider flies...

[john smith 19]

X-51 presentation.

http://sfte2013.com/files/78961102.pdf

Interesting presentation on the nuts and bolts of running such a test and, incidentally the sort of issues that launching a wing mounted LV would probably face.

I guess the bottom line is for successful results, check and test everything and have a backup plan for plausible failures involving any part of the team or their equipment.

[Star One]

X-51 presentation.

http://sfte2013.com/files/78961102.pdf

Interesting presentation on the nuts and bolts of running such a test and, incidentally the sort of issues that launching a wing mounted LV would probably face.

I guess the bottom line is for successful results, check and test everything and have a backup plan for plausible failures involving any part of the team or their equipment.

One thing that I found curious from a quick glance through it, is that it talks of carrying any future weapon developed from it internally on a B-2 or externally on the F-35. But why not mention the LRS-B which I would have thought the main platform for it, it's not like the existence of the program is a secret?

[john smith 19]

One thing that I found curious from a quick glance through it, is that it talks of carrying any future weapon developed from it internally on a B-2 or externally on the F-35. But why not mention the LRS-B which I would have thought the main platform for it, it's not like the existence of the program is a secret?

This is at present only a potential weapson system and I think it's fair to say so is the LRS-B, the B-2 and F35 OTOH are live deployed platforms.

[RanulfC]

One thing that I found curious from a quick glance through it, is that it talks of carrying any future weapon developed from it internally on a B-2 or externally on the F-35. But why not mention the LRS-B which I would have thought the main platform for it, it's not like the existence of the program is a secret?

This is at present only a potential weapson system and I think it's fair to say so is the LRS-B, the B-2 and F35 OTOH are live deployed platforms.

My curiousity was tickled by the fact they didn't mention external carry on the F-22... For the last decade EVERY "future-weapons-system" in the pipe has been shown on every platform specifically including the F-22/35. I had access to books that showed the mounting points for everything up to and including the SAL (Surface Attack Laser pods that never got tested) and hypersonic attack missiles. Not mentioning the F-22 as a carrier platform is very interesting to me

(And before anyone asks, no about 2/3rds of the systems depicted are/were never fully developed but the easyist thing to figure out is where to put them on an airframe if you have a general clue to what they might be shaped like and/or weigh )

Randy

[sghill]

One thing that I found curious from a quick glance through it, is that it talks of carrying any future weapon developed from it internally on a B-2 or externally on the F-35. But why not mention the LRS-B which I would have thought the main platform for it, it's not like the existence of the program is a secret?

This is at present only a potential weapson system and I think it's fair to say so is the LRS-B, the B-2 and F35 OTOH are live deployed platforms.

My curiousity was tickled by the fact they didn't mention external carry on the F-22... For the last decade EVERY "future-weapons-system" in the pipe has been shown on every platform specifically including the F-22/35. I had access to books that showed the mounting points for everything up to and including the SAL (Surface Attack Laser pods that never got tested) and hypersonic attack missiles. Not mentioning the F-22 as a carrier platform is very interesting to me

(And before anyone asks, no about 2/3rds of the systems depicted are/were never fully developed but the easyist thing to figure out is where to put them on an airframe if you have a general clue to what they might be shaped like and/or weigh )

Randy

Does it make any sense to carry it on an F-22? 

It wouldn't be terribly good as a replacement short range missile where a rocket motor is better for hitting other aircraft. 

You'd want one for medium and long range strikes, and that means you're going after fixed or slow targets that can potentially defend themselves, so the developers will want a correspondingly large warhead.  So quickly, it becomes a weapon for tactical or strategic bomber mounting and not fighter mounting.

[RanulfC]

Does it make any sense to carry it on an F-22?

The F-22 is still a multi-role platform in that it can and is designed to carry both tactical and strategic weapons. An F-22 can, in theory, carry a cruise missile an F-35 can not. (Part of the whole "argument" over the F-35 is that it is an F-16 "replacement" that cannot in fact perform some of the missions the F-16 can. Of course if one wants to get technical the F-22 can't do a lot of what the F-15 can do either but that's the 'breaks' for having a fifth generation fighter )

It wouldn't be terribly good as a replacement short range missile where a rocket motor is better for hitting other aircraft.

Actually you have that half right and half wrong It would NOT in fact be a good replacement at all for short range missiles because a hypersonic missile needs to accellerate from less than Mach-2 to over Mach-5 HOWEVER it fits right in with some anti-aircraft roles for longer range intercept missiles. A mission similar to the cancled ASLAM (Advanced Strategic Air-Launched Missile) secondary mission which was to take out Airborne Warning and Control aircraft from long distance but WITHOUT using as Nuclear Warhead.
(ASLAM info:http://www.designation-systems.net/dusrm/app4/asalm.html)
NOTE that the ASLAM itself with an fixed inlet and exhaust accidently reached a speed of Mach-5.5 and had a desiged sustained speed of Mach-4.5.

With such a misson parameter the hypersonic strike missile is expected to be too fast for the target to be able to move out its way before impact.

You'd want one for medium and long range strikes, and that means you're going after fixed or slow targets that can potentially defend themselves, so the developers will want a correspondingly large warhead.  So quickly, it becomes a weapon for tactical or strategic bomber mounting and not fighter mounting.

None of this makes the case BETTER for the F-35 over the F-22, which was my entire point. The ONLY factor the F-35 has going for it is that there are supposed to be MORE of them than the F-22 but you still run headlong into the issue of size. (It does matter in weapons systems despite what you might hear otherwise )
I'd point out that at Mach-5+ there would be less not more warhead because at those speeds you begin to get into impact being almost enough "bang" in and of itself or that's the hope at least. You don't need a bigger warhead because your target can't move as far from launch to impact and therefore (the theory goes) you don't need as much explosives because you have a much larger chance of actually hitting the target instead of just nearby.

In the end your hypersonic missile isn't going to be something small and compact as an Air-to-Air missile (examples: AMRAAM and AIM-9X) but something the size of an AGM-65 (Mavrick) or such for ground attack and probably for air-to-air as well and while the F-35 can carry a Mavrick something the size of an F-22 can carry more among other factors.

Mentioning that such a weapons system "can" be carried externally (really there's no hope of carrying something of the assumed size of a hypersonic strike missile "internally" on a fighter airframe in the first place so why that's mentioned that way is another question) on a "fighter" makes sense but suggesting that such an airframe would be the F-35 is going to make a lot of people sit up and take notice in the wrong way any way "I" look at it. And I can't shake the feeling that's exactly what and why it was done...

Randy

[RanulfC]

Oh and since we're going in that direction I'll point out again that the ASLAM was a SUBSONIC combustion ramjet engine and IT did Mach-5.5 by ACCIDENT with a non-optimized inlet and exhaust so... Tell me again why we "need" a SCramjet engine in the first place?
Let me drop a few other links while I'm at it:
The French tested a Mach-5 (subsonic combustion) Missile in 1966:
https://archive.org/details/nasa_techdoc_19670008070

Some discussion and notes:
http://gravityloss.wordpress.com/2008/01/23/hypersonic-cruise-for-the-v-prize/

I'll find some more given time but the X-51 tests actually make it much harder to find SUBSONIC combustion ramjet information these days

Randy

[sghill]

Mentioning that such a weapons system "can" be carried externally (really there's no hope of carrying something of the assumed size of a hypersonic strike missile "internally" on a fighter airframe in the first place so why that's mentioned that way is another question) on a "fighter" makes sense but suggesting that such an airframe would be the F-35 is going to make a lot of people sit up and take notice in the wrong way any way "I" look at it. And I can't shake the feeling that's exactly what and why it was done...

I don't think it'll be an F-35 mounted weapon at all (nor an F-22 weapon).  More like a B-2 and B-3 mounted weapon.

[RanulfC]

I don't think it'll be an F-35 mounted weapon at all (nor an F-22 weapon).  More like a B-2 and B-3 mounted weapon.

"Probably" correct but there are reasons to mount such weapons on a smaller more "agile" airframe, but zero for even mentioning it "might" be carried by something that would never be used

As I said originally, that's curious

Randy

[john smith 19]

Oh and since we're going in that direction I'll point out again that the ASLAM was a SUBSONIC combustion ramjet engine and IT did Mach-5.5 by ACCIDENT with a non-optimized inlet and exhaust so... Tell me again why we "need" a SCramjet engine in the first place?
Let me drop a few other links while I'm at it:
The French tested a Mach-5 (subsonic combustion) Missile in 1966:
https://archive.org/details/nasa_techdoc_19670008070

A fascinating paper. Note that Mach 5 with subsonic combustion was a designed and achieved goal in 1966.  This was not an "accident." Check that chart of part temperatures

Imagine what data could be collected today with such a test vehicle equipped with essentially the contents of PAYG mobile phone Of course you'd have to make sure the SIM card had a decent data plan on it.   

People forget that the French are AFAIK the only other nation to build a turboramjet powered crewed aircraft (actually I can't recall if they built one and one with separate jets and ramjets or if it was actually 2 turboramjets.  )

Returning to the thread topic the suggestion seems to be that for subsonic combustion ramjets a Mach range of 3 is possible for fixed geometry and the French paper has an inlet designed for M3.5 and expected to (and did) operate to M5  (how many variable internal geometry ramjet tests have there actually been?)

I know it's claimed the SCramjet is capable of continual acceleration through the Mach range but is that with a fixed geometry? It seems unlikely. My instinct is it has a range as well, but is it 3 Mach also ? More? Less?

Ever since I read about it I've liked the idea of "thermal choking" for changing the internal ramjet airflow. This idea of flow change by controlled heat addition (I wonder if there were any experiments done to see the effect of reducing propellant flow to some outlets from their ignition levels). It seems a lot more straightforward (remote control fast(ish) acting valves are not very exotic pieces of hardware) to implement than tricky (potentially) 3d motions of heavy lumps of hardware with substantial airflow forces on them.

Heavy x complex motion x high temperature x gas tight seal(?) --> Monumental PITA. 

[Vahe231991]

The Hypersonic Air-breathing Weapon Concept (HAWC) that was tested from September 2021 to January 2023 in many respects reminds me of the X-51 in its design philosophy, and it thus constitutes the second aerospace vehicle in history to achieve sustained hypersonic air-breathing flight. The Hypersonic Attack Cruise Missile (HACM) under development by Raytheon and Northrop Grumman, if it passes test flights once built, could become the first operational hypersonic cruise missile of the USAF.