The X-43A Flew at Mach 9.6 and 110,000 Feet — No Air-Breathing Aircraft Has Gone Faster in the 22 Years Since

Posted by AlbinoAkon@reddit | WeirdWings | View on Reddit | 60 comments

The X-43A was a small experimental research aircraft designed to flight-demonstrate the technology of airframe-integrated supersonic ramjet or “scramjet” propulsion at hypersonic speeds above Mach 5, or five times the speed of sound. Its scramjet engine is an air-breathing engine in which the airflow through the engine remains supersonic. The X‑43A was designed to be flown once and not recovered. It was one of NASA’s “better, faster, cheaper” programs developed in the late 1990s. The aircraft weighed about 3,300 pounds, and the program cost $230 million.

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RocanMotor@reddit

My professor had a hand in the design of the scramjet while working with LM. I joked and asked if he and his team members had shirts that said 'hypersonic engine development'

They did.

The other guys had 'supersonic' on their shirts.

Apparently there was a hierarchy in the lunchroom.

One of the most brilliant and intense proressors I've had the honor of studying under.

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mta1741@reddit

I don’t get it

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RocanMotor@reddit

You get a subsonic shirt.

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ComprehendReading@reddit

Cool story.

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daygloviking@reddit

Anyway how’s your sex life

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ShakyBrainSurgeon@reddit

Oh, hi Mark!

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Striking_Reindeer_2k@reddit

A friend in the air force pointed out how engines keep getting more powerful, but top speed seems to have plateaued. He said, "as far as you know". This was late 90's.

F4, F14, F15, F22.... beyond?

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Hillsarenice@reddit

Above Mach 2.8 everything starts to melt or soften. Aluminum, fibres, glass. You are left with problematic honeycomb steel(XB-70) or titanium(SR-71). Or other even more expensive exotic options.

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decollimate28@reddit

It wouldn’t be a problem whatsoever in this day to build Mach 3+ plus aircraft. Except for stealth. Advances in manufacturing, materials, cooling - really not an issue. there’s just no need.

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WarthogOsl@reddit

And a lot of airplanes are limited by their canopies. You probably won't see a bubble canopy fighter like an F-15 go much faster than Mach 2.6. The F-111, with a flush canopy, was apparently limited by the seals around it melting. There are rumors of one briefly reaching Mach 3, though.

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Hillsarenice@reddit

I read that account of the F111 going mach 3. Seems unlikely Other pilots said it was engine limited to Mach 2.3. I wonder if what pilots were doing was going max speed at altitude and then turning on the TFR. Coming out of a dive and then going Mach 1.4 at 300 feet might melt some stuff. They probably weren’t supposed to do this but it would be quite the roller coaster.

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WarthogOsl@reddit

I heard the opposite: That it wasn't engine limited, but airframe limited, and it would just continue to accelerate. But that's a pilot story as well, so...grain of salt.

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WarthogOsl@reddit

In terms of fighters, Mach 2+ speeds haven't really been a priority since the 60's. That's why pretty much every US fighter since the F-16 has a non-variable inlet. Still, more power gives you better acceleration and a better thrust to weight ratio.

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novwhisky@reddit

None that we know of

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DeficiencyOfGravitas@reddit

Nah. From 1990 to, well, pretty much today, the number one goal of the American military industrial complex wasn't to make weapons. It was to make money. You can't sell hidden technology. So why bother hiding it? There will never be a peer to peer conflict ever again (this was unironically the attitude of the 90s).

Now that we're shifting back to a mutipole world, secret projects are going to be a thing again, but for the last 3 decades we've been living in a world where profit takes priority over survival.

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Remarkable-Sun3664@reddit

This is a logical fallacy, we aren't customers so why should they show us?

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CivilCaregiver6519@reddit

Additionally, it assumes that the for profit companies are the exclusive drivers of innovation and development. We know that DARPA is a thing, and it would not surprise me if there is other, black budget, r&d going on that we have never heard of.

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hoppertn@reddit

There’s a line from a movie “do you think they really pay $10,000 for a toilet seat or $2,000 for a screwdriver?”

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SN6123@reddit

Was a mechanic on CH-53’s, some of those nuts and bolts get that expensive. That’s mission critical though, so another personal example. I work at a VA hospital, what we are forced to pay for mundane crap is insane. Blue microfiber cloth for housekeeping? $7 a rag. Caster wheels for our linen cart? $1500 per non steer, $1700 per swivel.

I get what your saying, they hide costs in the budget - but when companies know they can bend Uncle Sam over and ravage his budget they will absolutely charge $20k for a hammer

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novwhisky@reddit

Can I get the name of that movie?

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soBouncy@reddit

Independence Day

"You don't actually think they spend $20,000 on a hammer, $30,000 on a toilet seat, do you?"

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novwhisky@reddit

Oh duh, should have known!

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Unlikely-Answer@reddit

elon definitely has an underground den of dweebs working on cool Mars stuff

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DeficiencyOfGravitas@reddit

we aren't customers

Who is we, kemosabe?

If you live in a military city, you'll see newspaper ads and billboards from the MIC advertising very specific products. Buy this phased radar array! Buy this jet! Buy this submarine!

You guys are seeing this as exclusively amateur. But professionals who work in or adjacent to the military are the target audience for these products. And not just American. Globally. How can Lockheed Martin get you to buy their products if you don't know about it?

In the past, this type of information was secret (I don't mean that in the colloquial sense, but secret in the formal way). Now it is not because how can you convince Denmark to buy F-35s if they don't know it exists?

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2wheels30@reddit

That's not true at all. Most of the "mainstream" aircraft programs were never secret, regardless of their desire to export them or not. The F15, F14, F18, F16, etc were never kept from public view. There were classified elements, but everyone knew about them. The F35 is the same. That's how it's always been and it's the same today.

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Crag_r@reddit

You can't sell hidden technology. So why bother hiding it? There will never be a peer to peer conflict ever again (this was unironically the attitude of the 90s).

Minus the ~dozen research and demonstrator designs that have popped up since 2020 that were secret when first flying.

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Afrogthatribbits@reddit

Project FALCON, HTV-3X Blackswift, Lockheed's SR-72, the SR-72 single engine demonstrator (likely flown by now), etc.

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_BMS@reddit

Publicizing military projects for sales purposes only matters if they are meant to be sold to other countries.

There's zero reason to publicize systems meant for US-use only. The heavily modified stealth Blackhawks are probably the best example of this.

The public did not know about them beforehand and likely would still not know about them if not for the fact that one crashed during the operation to get OBL. And regardless, those helicopters have never been mentioned again by the military or whatever contractor might've been hired to make them.

Similar story with the RQ-170 which was not officially acknowledged for a long time and then the RQ-180 which still hasn't been acknowledged at all. People aren't even sure if "180" is even the official designation for it.

For every "well-known" special operations unit/R&D agency or new advanced hardware the military confirms the existence of, it's certain there's more that the public don't know about at all.

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jar1967@reddit

They have a customer , the USAF

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novwhisky@reddit

My brother in christ, profit IS survival in this country

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RocanMotor@reddit

I can't confirm.

Or deny.

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Ogre8@reddit

Me either.

Mostly because I have no idea.

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hoppertn@reddit

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YogurtclosetDull2380@reddit

They just let it fly away? Like they had no use for any information regarding the materials or anything?

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bemenaker@reddit

It was loaded with tons of sensors. It was a technology test bed. They made multiples of these and flew them. This wasn't a one of. A couple crashed, and then they kept getting faster.

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IntelligentVictory91@reddit

I believe there was some discussion about adding skids that would pop out of the upper surface but the approach speed would have been something like 325 mph and controllability was questionable besides it was full of sensors and there was little free space.

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pesca_22@reddit

to crash make them going faster? amazing!

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francis2559@reddit

Some say it is still flying

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mz_groups@reddit

All we know is that it's called The Stig

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mz_groups@reddit

I think they just wanted to establish flying characteristics and the combustion characteristics for the scramjet. Mostly, they wanted to show that they could generate positive net thrust, which they did. Telemetry was enough. I'm sure getting it back would have been a "nice-to-have," but it wasn't worth the additional cost/complexity.

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EmotionalBrontosaur@reddit

Excellent slides off of NASA.gov on the X43A program.

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Key-Employee3584@reddit

Sources tell me that someone went just over Mach 10 and even managed to survive the breakup. /jk

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Asleep-Mouse1648@reddit

ik that the daarpa htv 2 is a missile but it is a hypersonic glider and glider are aircraft and it traveled a little less than 2 times the speed of sound

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He-who-knows-some@reddit

Jesus that’s a tiny ass research platform no kidding! I’ve seen photos of this thing and assumed it was like other research platforms and was 30-50’ long..,

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Unusual_Specialist@reddit

Project Aurora would like a word.

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eruditeimbecile@reddit

I beg your pardon, I have personally witnessed the SR-72 Darkstar hit Mach 10 in level flight.

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joe9teas@reddit

Warwick Davis was pencilled in as first test pilot but other commitments caused NASA to shelve a manned prototype.

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ComprehendReading@reddit

That really dwarfs the misconception of NASA's capabilities by u/joe9teas.

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joe9teas@reddit

I apologise for any inappropriate comments

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Kruse@reddit

Uh, what? April 1 was yesterday...

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joe9teas@reddit

Well, my disclosure is being voted down which suggests US intelligence is trying to keep a lid on things.

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ComprehendReading@reddit

Hi! I'm Cunty, your helpful MircoSwell Word A.I.

It appears you want to make a joke. Did you need help making a joke?

I suggest making a clarification between U.S. intelligence, and American intelligence, because neither have any identifiable intelligence.

Did you mean: U.S. Government Intelligence, or did you mean American citizen intelligence?

Warwick Davis is likely not the [name or noun] you intended. Did you mean joe9teas is a chav?

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