
When the DC-8 Went Supersonic (2011) - curtis
https://www.airspacemag.com/history-of-flight/i-was-there-when-the-dc-8-went-supersonic-27846699/?all
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scrumper
Good story, and a great example of test pilot presence of mind as the crew
discovers that the elevators don't work...

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bwanab
I miss the DC-8. Always my favorite jet in my younger days. Those things felt
like rockets taking off.

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Zaak
I have similar feelings about its descendant the MD-80. The power to weight
ratio on takeoff was a lot of fun.

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dbcurtis
Yup. The MD-80 takeoff inspired confidence.

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InTheArena
Near criminally stupid though. Not only did they have issues with two separate
control surfaces, a unplanned stall and a safety violation on takeoff, they
did all of these things for a marketing piece establishing the plane was safe.
This at a time where metal fatigue and structural load was not well
understood, as the Europeans where finding out as their planes decompressed
explosively midair.

There was a 747-SP that went supersonic by accident and was only saved by the
crew deploying the landing gear to slow the plane down. He amount of damage
was non trivial.

Someone will probably jump all over the critics of Douglas and point out
Boeing’s Tex Johnson’s barrel row. 1) that was not endorsed by the company and
2) was a neutral G maneuver. 3) the company appropriately freaked and told him
never to do that again.

We have occupational safety and standards operating procedures for a reason.

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qwerty_asdf
Since when is voluntary experimentation on a test rig, under controlled
circumstances, criminally stupid? It’s not like this was a passenger flight.

It would warrant criticism if the pilot tried it without informing the crew
prior to takeoff. All participants entered into the activity with an
understanding that they were risking their lives.

These people did it because they enjoyed the challenge, not to score points
with corporate overlords or jockey for a raise and a promotion. The marketing
angle was simply to provide cost justification and demonstrate that a
perceptible reward would be earned with the risk undertaken.

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InTheArena
That's a optimistic reading of the article. The article states it was for
marketing reasons, and also states that they had several plan threating
outcomes that were not planned for.

If it where in the context of understanding the plane's behavior at trans-
sonic speeds, I can understand it, but that is not really given as a
justification.

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throwanem
What surprised me the most was that they did it on purpose!

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mirimir
Two reasons are pretty clear from the article. It was fun. And it could be
sold to management as safety PR.

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cratermoon
The engineering data alone from the flight was worth the risk. What they
measured and learned during the flight probably gave the aircraft designers at
Douglas priceless insights.

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haltingthoughts
Modern aircraft undergo testing near the speed of sound to find issues as
well.
[https://youtu.be/rpP7hsuVuoE?t=1155](https://youtu.be/rpP7hsuVuoE?t=1155)

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jtchang
What does it mean when he says he pushed over into the dive more? Does that
mean he went faster down?

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stcredzero
Yes. To relieve stress on the stabilizer.

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freeone3000
In a dive.

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nathanm412
The biggest issue wouldn't have been designing a power system that could bring
a jet to mach speeds. The bragging rights for them were that the plane
survived the transition to mach 1.

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craftyguy
Does something magically happen at Mach 1.0 that would compromise structural
integrity significantly more than, say, Mach .99...9?

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qwerty_asdf
If you read the parts where they mention “buffeting” that’s the dangerous
part, where uneven airflow introduces instability, causing the airframe to
rattle.

Buffeting occurs when the soundwaves of the noise of the craft and its motion
directly affect the air as it flows across the surface of the plane.

This happens as the plane enters the shockwave of the sound barrier, and
ceases when they accelerate beyond the speed of sound.

At and beyond Mach 1 the buffeting is behind the plane, and flight is
smoother, with no rattling or shaking from the incidental turbulence.

It also happens when decelerating, although it’s easier to decelerate safely
through the buffeting quickly, since less time is spent in the shockwave, and
a reduction in speed grants improved control.

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craftyguy
I see, thanks for the explanation

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dfrey
Queue up the Ryan Reynolds "But Why?" gif for this one I think.

