60 years ago: The famous Boeing 707 prototype barrel roll over Lake Washington | Hacker News Reader

60 years ago: The famous Boeing 707 prototype barrel roll over Lake Washington

seattletimes.com

201 pointsTuring_Machine61 comments

Interestingly enough, if the occupants weren't looking outside, a "1G roll" would feel almost the same as level flight; here's a video showing how "gravity" seems to invert along with the plane:

https://www.youtube.com/watch?v=pMWxuKcD6vE

This is also why pilots can become spatially disoriented:

https://en.wikipedia.org/wiki/Spatial_disorientation

The article quotes the pilot, Tex Johnston, saying something similar,

"The airplane does not recognize attitude, providing a maneuver is conducted at one G. It knows only positive and negative imposed loads and variations in thrust and drag. The barrel roll is a one G maneuver and quite impressive, but the airplane never knows it’s inverted.”

Problem is, it isn't actually a 1G manoeuvre. You can only have a constant 1G if you are in straight and level flight. If you perform a gentle turn, you will have very slightly more than 1G as you bank around the turn.

With roll, if you pull positive 1G while inverted, the plane will effectively be accelerating towards the ground twice as much as if it was in free fall. When the roll is over, in order to regain straight and level flight, more than 1G must be pulled to counteract the groundwards velocity that has been accumulated.

Of course. Level flight isn't exactly 1G either because of small amounts of turbulence. The point is that the load is arbitrarily close to 1G, given a slow enough roll (and enough altitude).

A descending turn can be done with <1G - it's only a level turn will pull more than 1G.

Yes, you can do a descending turn, with <= 1G. However, you will then come out of it going down, and unless you want to fly into the cumulogranite you will need to pull > 1G in order to level out again.

If you really want to be pedantic, going east in level flight you are at less than 1G due to orbital momentum and in vary small part due to altitude. So, in theory you could do all of this and stay under 1G.

PS: The weight thing can be significant for hypersonic+ aircraft. Also, you use slightly less fuel going east than west due to earth’s rotation, though winds are going to be far more important.

To be truly pedantic, you could be landing and execute a slow sinking flare, which can be < 1G right up until the moment the wheels contact the pavement and the momentum of the aircraft results in > 1G force - but then you aren't flying any more!

Ok that's impressive. I'd definitely pay extra for my Ryanair holiday flight to do that once or twice!

Somewhat related, great piece of writing about the banked turn - http://www.theatlantic.com/past/docs/unbound/langew/turn.htm

Even seen Bob Hoover do a "1G roll"?

https://www.youtube.com/watch?feature=player_detailpage&v=9Z...

What were you doing Tex?

I was selling airplanes.

https://www.youtube.com/watch?v=Ra_khhzuFlE

Here's Boeing, doing a 'near vertical' takeoff in the Dreamliner (spoilers: not really but still impressive), also presumably selling airplanes.

https://www.youtube.com/watch?v=KYbM-3E11Qo

I was at the Farnborough airshow in 1998. Farnborough is one of the largest commercial/trade airshows in the world. Wikipedia says that $72bn worth of aircraft were bought at the last show.

The commercial jets are really thrown around at the show. Steep take offs and really tight banked turns low to the ground so that the aircraft can remain visible to the people at the airshow.

https://www.youtube.com/watch?v=T3EgoPDBvLc

The planes are more than capable of these manoeuvres, but paying passengers don't want to imagine themselves riding in those planes. Passengers want slow, steady and graceful flights that wont spill their drinks or upset their stomachs.

I use this example whenever I'm presenting on the difference between 'Radical' (High Risk, High Return) and 'Strategic' (Low Risk, High Return) plans. The difference between the two is Capability - ie, having strategic capability lowers risk.

This barrel roll, while not a strenuous manoeuvre on the 707, nevertheless demonstrates confidence in Boeing's manufacturing capability and by executing it Tex Johnstone convinced plane buyers that purchasing a jet was not a high risk strategy. "Selling planes" indeed!

It's not really a "low risk" maneuver to do an aerobatic maneuver on an aircraft that isn't certified for it and that doesn't have a g-meter. Ask the crew of the Lufthansa B720 that crashed trying to do a roll in 1964.

http://aviation-safety.net/database/record.php?id=19640715-0

When you hire a pilot with the nickname 'Tex', expect showmanship.

That aircraft is more properly called the 367-80, or "Dash 80". While it did serve as the prototype of the 707, its fuselage isn't as wide.

The KC-135 tanker and its derivatives also derive directly from the Dash 80, rather than the 707. It retains the 80's more narrow fuselage.

And the article says thus: It had become Johnston’s job to travel all over the U.S. to show off the Dash 80, as the 707 was code-named.

It does, it's just kind of wrong. Things are more interesting than that.

Dash 80 was a nickname for that particular plane, it's model number is 367-80. The 707 is a slightly different aircraft that generally isn't referred to as a "Dash 80".

The Dash 80 was the prototype for the 707, but strictly speaking, it's model number isn't 707.

It's also claimed, though there's no footage in existence, that a barrel roll has been performed in a Concorde.

https://www.youtube.com/watch?v=KYQS3qAIjAo

It has to be true. I saw it in a cheezy B movie, surely it wasn't special effects?

Or maybe it was just a roll, not a barrel roll. I can't remember, it's been 35+ years and I don't want to see the movie again. Anyway, we were expected to believe that the Concorde is maneuverable enough to evade both a SAM and missiles from a fighter. My "suspension of disbelief" unfortunately didn't kick in. https://en.wikipedia.org/wiki/The_Concorde_..._Airport_%2779

Hmmm ... reading the Wiki entry makes me think about wanting to see that movie again. So many bad disaster films were made in the '70s.

If you watch the video Sosuke posted, the Concorde seems surprisingly maneuverable. Probably since it has a short span so it can roll quickly and a large amount of thrust.

Actually, the movie used models, you can see the loop scene here: https://www.youtube.com/watch?v=Ny_JslCCPxk&feature=youtu.be...

Technically called an aileron roll.

https://en.wikipedia.org/wiki/Aileron_roll

No, a barrel roll is different to an aileron roll. The wikipedia article linked to shows the difference.

A barrel roll requires heading and altitude changes, an aileron roll should not.

Yeah it's was confusing, an aileron roll wouldn't allow for this https://www.youtube.com/watch?v=pMWxuKcD6vE (posted above). Unless you rotate faster than gravity pulling the water down.

Yes, the are different. However what the OP is pointing out is that Tex actually did an aileron roll and not a barrel roll. (Watch the video and it's pretty obvious).

I watched the video and it looks like a barrel roll to me. The airplane doesn't maintain altitude nor heading. Also that engineer who took a photo while kneeling next to a window would have been on the ceiling at that point if it had been an aileron roll.

If you look at 1:56 on the AviationExplorer video you'll see there is little or no pitch change, so it couldn't be a barrel roll. I'm not sure how you can tell that it's heading is changing from that video.

According to wikipedia "An aircraft performing an aileron roll will actually fly along a slightly helical path, and a very light, positive g force will be maintained" so the photographer wouldn't have been on the ceiling.

I don't know which AviationExplorer video you're referring to, but there's supposedly only one video of the maneuver so I assume the one in the article is the same thing.

I see quite a large pitch change there. The aircraft starts more or less level, then pulls up. While inverted it begins to move substantially nose down. As for heading, at the beginning of the video it's pointed well to the left, and at the end of the maneuver the fuselage is lined up with the camera.

Wikipedia is confused or imprecise. Either that "positive g force" refers to the force on the aircraft relative to the Earth, or it's just wrong. Reading through the original reference that statement comes from, I believe it's the former. The book says:

"...we have managed to substantially increase the angle of attack, to a point where the inverted wing is capable of maintaining altitude."

If you're maintaining altitude while inverted, you're not pulling positive gees relative to the airplane, but you are pulling positive gees relative to the Earth.

You can browse most of the chapter on aileron rolls in the book in question on Amazon:

http://www.amazon.com/Basic-Aerobatics-Geza-Szurovy/dp/00706...

https://www.youtube.com/watch?v=AaA7kPfC5Hk

See around 1:56. No significant heading or pitch changes that I can see, although it is difficult to tell because the camera is so far away.

Correct, a barrel roll requires 90 degree changes-of-course through the manouevre.

Think of the seam-line on a toilet-roll tube; that's the path a barrel roll requires. Lots of pitch and roll, it is not a simple manoeuvre and has to be taught:

https://www.youtube.com/watch?v=hASm6-2QLDU

To my knowledge no airliner has ever been barrel-rolled, it is a high-stress manoeuvre.

Tex himself never claimed it was a barrel roll.

To my knowledge no airliner has ever been barrel-rolled, it is a high-stress manoeuvre.

Tex himself never claimed it was a barrel roll.

I think you've confused them; Tex says, quoted in the article, "The barrel roll is a one G maneuver and quite impressive, but the airplane never knows it’s inverted", while the aileron roll causes negative G at the "top" when the plane is inverted.

Tex is incorrect or misquoted, a 1G barrel roll is next to impossible. More than 1G must generally be pulled at the entry point if you're even going to make the first loop. Even aerobatic champions in Su-26s struggle to do it, and those things have ridiculous power-to-weight.

Furthermore, if you were watching a barrel roll you'd see the aeroplane's nose turn towards you as an observer. That'd didn't occur.

What did Tex call it? The exact words out of his mouth:

"So I came across and did a chandelle"

https://www.youtube.com/watch?v=hASm6-2QLDU

Well, it certainly wasn't that as a chandelle is an FAA-certified check-manouevre involving a climbing turn.

I know it's heresy to question 'national heroes' but frankly Tex didn't know what manouevre he did.

All we know is he hacked something on the day, and it worked.

> Furthermore, if you were watching a barrel roll you'd see the aeroplane's nose turn towards you as an observer. That'd didn't occur.

Not if the entry trajectory is away from you, as is the case in all the videos I have seen - were you thinking of Tex's description of it as a chandelle here?

He uses the unqualified term 'roll' elsewhere in the interview, and the maneuver certainly qualifies, as the craft performed a 360-degree rotation around the longitudinal axis and finished on close to the entry heading. Movement of the camera to follow the aircraft may have concealed its barrel shape, but if you follow the fuselage orientation, you can see changes in heading consistent with a barrel roll, though possibly around an oval or pear-shaped barrel.

Regardless of what you call it, I don't think the maneuver as filmed could be performed at nearly 1G. I wonder if what Hoover was trying to convey was 1) he didn't go negative G, and 2) he didn't pull any more Gs than a chandelle, which, as you say, is a standard check-maneuver (I do not know if the latter is true (with respect to G forces), though the entry into, and exit from, a barrel roll have some resemblances to a chandelle.)

Are you confusing a roll with a loop???

I fly RC, and pulling back hard on the elevator will rip the wings off a plane, particularly at the bottom of a loop. Alas, I know this from personal experience :-)

Just rolling around the longitudinal axis with the ailerons is pretty low stress, though, at least in a "snap" roll. You loose some altitude, but the load on the wing at the end of the roll is pretty minimal.

Making small elevator changes during the roll to pull back (generate positive G) during the sideways and inverted parts of the roll, and ease off (preventing more G than just gravity/lift of wing) as you return to an upright position is doable with practice. You will loose some altitude, it won't be a "straight" tube/barrel traced.

No. The 707 did an actual Barrel Roll, not an Aileron Roll.

No, definitely not a barrel roll. Watch the video and it's clearly obvious that it's not a barrel roll. Also, a barrel roll isn't a 1g maneouver.

The only 1g maneuver that starts and ends with level flight is level flight.

An aileron roll will experience -1G - something you really don't want to do in an airliner. A barrel roll is specifically named because its like driving around the inside of a barrel; the plane always maintains positive Gs.

I'm stunned that Bill Allen left behind the photo he was presented with at the banquet. While he may have not liked it at the time it seems like he never forgave or recovered from it.

Is there anything about the Boeing 707 structurally that makes it possible to do a barrel roll that would not be possible in later generation jets, such as the 757, 767, 777 and 787?

No. A barrel roll doesn't place much in the way of demands on an airplane's structure.

Non-aerobatic airframes are not designed to pull high negative G's. The other problem with negative G's is the junk that accumulates in the bottom of the airplane can fall upwards and cause problems.

This is why Tex was careful not to pull negative G's.

How quickly would the 707 drop in altitude while doing a barrel roll? And did he need a minimum speed to be able to successfully do it (sort of like an escape velocity)?

If it is truly a 1G maneuver, then the answer would be:

    9.8 m/s^2  *  (1-cos(\theta))

Where \theta is the angle off of level flight. So when you are fully inverted, the plane would be accelerating at 2 G's downward (one to feel like you were in free-fall inside the cabin, and then one more to push you back into your seat).

In the film, the roll takes about 12 seconds. A quick numerical integration shows that by the end of the turn you would be 700m lower than you started, and have a downward velocity of 120m/s. I'm not a pilot, but I'm sure that the best practice here would be to start with an upward velocity, and not to really keep 1G throughout the turn. Those could both lessen your loss of altitude.

That picture is one of the two most famous aviation pictures. The other one, of course, is the 1903 first flight.

Perhaps inspired by Falk's performance in an Avro Vulcan prototype at the '55 Farnborough, which I think was in July.

https://www.youtube.com/watch?v=afj19PedlxE

Does the size of the plane make executing a roll of this nature challenging?

I wouldn't believe so - as Tex explained:

“The airplane does not recognize attitude, providing a maneuver is conducted at one G. It knows only positive and negative imposed loads and variations in thrust and drag. The barrel roll is a one G maneuver and quite impressive, but the airplane never knows it’s inverted.”

As long as you have enough thrust and the plane can withstand the G force, it will roll.

Yes, I as a layperson can see all sorts of differences that impose large problems. More mass = larger moment of inertia, slower roll, larger "barrel", and more energy needed. The roll could take 3x longer in a large plane, but other things like max speed and power to weight are not 3x better.

Is it unreasonable to expect the ability to barrel-roll from any motorised plane (i.e. not a glider)?

Any airplane should have no problem--but legally, not allowed unless it is certified for it.

Any U.S. pilot caught pulling such maneuvers would be pwned by the FAA. Any Boeing-employed pilot would be summarily fired as well.

It's also not a good idea. See for example the Lufthansa crash on 15 July 1964 where they tried to roll a B720 during a training flight:

http://aviation-safety.net/database/record.php?id=19640715-0

A jumbo barrel/aileron roll needs to be practiced in a highly-accurate simulator many times for performing on actual hardware to a high degree of repeatable success with least airframe wear, and then signed off by company folks and regulators. Otherwise, it's too risky.

Boeing sometimes puts some extreme maneuvers into the approved flight test card, which is performed with FAA approval.

There has been several cases of 737s being rolled (accidentally) without damaging the airframe.

When test pilots fly extreme maneuvers on an approved test profile, its usually done at high altitude, not airshow flyover altitude.

Before the famous 787 demo flight, the pilot flew the maneuvers in a simulator, and did some practice at higher altitude before doing a low altitude demo routine.

At Boeing, there's a fine line between selling jets and getting fired. The last order to Randall Lee Neville from CEO Conners was "no rolls."

No need for a motor, you can do it in a glider too.

I have a feeling that in today's corporate culture he would be probably fired.

According to the article, he was very nearly fired in 1950s corporate culture.

Regardless of intent or results, pulling an unsanctioned literal stunt with hardware that represents the majority of your company's assets is going to be frowned upon.

some sources say he was fired and then un-fired later in the day, when new aircraft orders started pouring in.

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