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Rock and roll!

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Alexander Howard
1322961.  Wed May 29, 2019 10:36 am Reply with quote

I get to be the first to post too.

In spite of all you have been told, all four members of the Beatles were born and brought up in West Derbyshire.

1322965.  Wed May 29, 2019 11:09 am Reply with quote

Very clever!

Actually, the Beatles played in the Liverpool suburb of West Derby in their early days:

DVD Smith
1322999.  Thu May 30, 2019 6:57 am Reply with quote

This story is more 'roll' than 'rock', but I had to share it :)

The annual Cheese Rolling Championships, where competitors chase a rolling cheese down a steep hill, took place in Gloucestershire this past weekend.

The cheese gets a one-second head start, and the hill used is so steep that the cheese can reach speeds of 70 miles per hour. The event stopped using a real cheese on the orders of the police, and the competitors now chase a lightweight foam "cheese" to prevent injury.

That hasn't been ultimately successful though - at the 2019 race this weekend one person was left with a fractured ankle, and the winner of the women's race managed to win despite spraining her ankle on her way to victory.

The first 2019 men's race was won by Mark McDougall, when he tripped and fell down the hill. Afterwards he said "It was better than last year when I knocked myself out." The person he came second to last year did not compete as he was on holiday.

DVD Smith
1323001.  Thu May 30, 2019 7:14 am Reply with quote

And speaking of rolling, here's my post from last year about why a barrel roll isn't necessarily what you think it is, and the guy who did a barrel roll in a jumbo jet.

DVD Smith wrote:
Q: What is the name of the aerobatic manoeuvre where a plane does a sideways flip while staying facing forward?

[Klaxon: Barrel roll]

A: It's an Aileron roll, or a slow roll.

What most people know as a "barrel roll" isn't in fact one at all. A barrel roll requires the aircraft to follow a helical path by doing a sideways flip and a loop-the-loop at the same time, as if the plane was flying around the outside of a barrel (hence the name).

The move used to be known as a "sideways somersault", and was first performed at an air show in 1905 by accident, when the pilot made a sharp turn too suddenly. His co-performer, not to be outdone, immediately repeated the manoeuvre twice. [1]

What most people think of as a barrel roll, the steady sideways flip with no vertical movement, is either known as an "aileron roll" or a "slow roll", depending on the speed of it. A slow roll is when the pilot rotates the aircraft without affecting the straight, steady, level course of the flight. An aileron roll is quicker and much more erratic, and is named after the flaps found on the edges of an aircraft's wings. [2]

Q: What's the biggest plane to successfully perform a barrel roll?

In 1955, Boeing's chief of flight testing, a man named Alvin "Tex" Johnson, managed to pull off two barrel rolls in a prototype Boeing 707 jumbo jet travelling 490 mph, in front of a crowd of 250,000 people. He did it without informing the president of Boeing, who found out when he watched it on television, and without telling his co-pilot or onboard engineer until they were already in the air. A few seconds of video footage has survived. [3]

And just for a bit of fun, go to the Google homepage on your web browser and search for "do a barrel roll". :) [4]

1323004.  Thu May 30, 2019 8:08 am Reply with quote

It was the Dash 80 (precursor to the Boeing 707), not a "jumbo Jet" - that name originally refered to all the new wide-bodies that were developed from rejected entries in a USAF strategic airlift competition (Boeing 747, Lockhead Tristar and MacDuck's DC-10) although after a few years usage changed to be solely for the 747. The "winner" of the strategic airlifter competition was the what became the Lockhead C5A Galaxy.

As winner Lockhead sold a total of around 130 aircraft. The "losers" each sold far more - over 1500 747s, over 400 DC-10s and over 250 Tristars, which goes to show that winning ain't always what it's cracked up to be.

Note that most airliner types (including concorde) have performed barrel rolls in their flight test development phases. It's a useful way to confirm that nothing in the instrumentation, navigation flight management and flight control systems gets "upset" in unusual attitudes. Whilst these aircraft would never be rolled in normal service they could be subjected to extreme turbulence or other failures which might place them in unusual attitudes, and this test give some confidence that the aircraft systems won't run away a hide when that happens. But these rolls are always barrel rolls (see below) , because positive G is maintained throughout the manoeuver. Doinf zero and negative G in aircraft not design for it can upset everything from the fuel feeds to the coffee dispensers, so it is avoided.

On the subject of rolling manoeuvres - having been in aviation for more than my adult life as enthusiast, pilot and aeronautical engineer (depending on when) I have to say I don't recognise those definitions!

The normal usages I am aware of are:

Roll (generic) - a manoeuvre in which an air craft rotates about a datum parallel to its logitudenal axis.

Axial Roll - a rolling manoeuvre in which the datum axis is the air craft's longitudenal axis

Barrel roll - a rolling manoeuvre in which the datum axis is vertically displaced from the air craft's logitudenal axis and in which positive vertical acceleration (aka "g") is maintained throughout the manoeuvre

Twinkle roll - a rolling manoeuvre which is executed using maximum available roll control (usually, but not always the ailerons)

Slow roll - a rolling manoeuver which is executed using significantly less than maximum available roll control. By convention a slow roll should take at least 5 seconds to complete, often much longer.

Hesitation roll - a rolling manoeuvre which is paused at regular points around the manoeuvre. A "four point hesitation roll (left)" would have the aeroplane rolled into a 90 degree bank (left wing down), held there for a short period, then rolled to inverted and held, then rolled into a 90degree bank (right wing down) and held before being rolled back to normal flight. Hesitation rolls ar commonly seen with four "points", but eight and even sixteen-point rolls are sometimes seen at airshows, and I have seen the much harder 3-point and six-point ones done sometimes. Hesitation rolls also come in "slow" and "fast", depending on whether the rolls between the pauses use large or small roll co2ntrol demands. Fast hesitation rolls look aggresive, but veru slow hesitation rolls are both harder to perform and much more elegant. Rotary wing air craft cannot perform hesitation rolls.

Snap Roll or Flick Roll - a manoeuvre in which the air craft intentionally induces an asymetric stall in forward flight, causing a rapid gyration about an axis close to (but not parallel with) the air craft's longitudenal axis. The flick is essentially a horizontal "spin" manoeuvre and (as with the spin) can be performed in positive (upright) or negative (inverted) variants. Snap/Flick and spin manoeuvres can only be performed by fixed wing aeroplanes, not by rotary wing, jetborne or lighter-than-air air craft.

In all the above there is an implicit assumption that the axis of the rolling manoeuvre must be a straight line, but with the exception of the flick/snap roll it's not an inherent constraint. A rolling circle is a roll where the axis of the roll is bent around in a horizontal circle (this is a very difficult manoeuvre to master, requiring high skills and lots of practice). It commonly involves eight rolls or four rolls to complete the circle, but the very best pilots in suitable aircraft have demonstrated rolling circles with only two, one and even a half roll completed through the horizontal circle.

There is a related manoeuvre called the rolling loop, but that requires extreme power-weight ratios to achieve and AFAIK is only done with radio-controlled model aeroplanes.

0.000008 supplied,


1323005.  Thu May 30, 2019 8:10 am Reply with quote

Oh, and for future reference - there is no such thing as a "loop the loop". There is a "loop" (a constant-rate vertical circle starting and finishing at the same point in space) but anyone using the term "loop the loop" risks being taken behind the bike sheds for some percussive re-education...



DVD Smith
1323006.  Thu May 30, 2019 8:22 am Reply with quote

Thanks for the clarifications! I'm very much a layman when it comes to that sort of thing so always happy to welcome corrections. :) Is the information I posted generally correct, or did I get it wrong entirely? I certainly had the wrong idea of what a barrel roll was when I first read the fact so I thought it could be a good General Ignorance question. (Plus I loved the details of the stories behind the first barrel roll and the Boeing test flight.)

Are there any videos demonstrating the different types of rolls you listed? It's hard to picture from a text description alone (especially since I tend to get my axes mixed up).

1323035.  Thu May 30, 2019 1:01 pm Reply with quote

DVD Smith wrote:
since I tend to get my axes mixed up).

Bad Youlgreave.
Naughty Step.

1323250.  Sun Jun 02, 2019 9:50 am Reply with quote

Going from rolling back to rocking - found this today and thought it might be worth sharing!

The world's largest rocking chair measures 17.09 m (56 ft 1 in) tall and 9.99 m (32 ft 10 in) wide, and can be found in the town of Casey, Illinois, USA.

What's really interesting is that Casey is also home to the world's largest golf tee, windchime, knitting needles, wooden shoes, pitchfork, and mailbox! All were created by one man, Jim Bolin.

There are many other 'big things' in the town, some of which aren't world records but are still pretty big! The list includes a pencil, a birdcage, a ruler, and a spinning top, all earning the town the affectionate slogan "Big things, Small Town".

Edit: source

1323257.  Sun Jun 02, 2019 10:10 am Reply with quote

DVD Smith wrote:
The annual Cheese Rolling Championships, where competitors chase a rolling cheese down a steep hill, took place in Gloucestershire this past weekend.

Growing up in Gloucestershire, childhood friends and I would replicate the annual cheese rolling with a small slope in a local park or school field, a few friends, and babybells! hahaha

1327006.  Fri Jul 19, 2019 7:44 am Reply with quote

Rolling bridge (for pedestrians)

Just a proposal, but the animation made me :-)

1327008.  Fri Jul 19, 2019 8:26 am Reply with quote

Besides the novelty value, what would be the advantage over a swing bridge?


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