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Also started reading 'Jet: The engine that changed the world by Graham Hoyland and have only got to page 15 and have already lost faith in the author who in trying to explain the principle of thrust uses the example of a blow up balloon which when inflated and then released untied will fly around due to Newton's 3rd law as the air escapes. All well and good but he then characterises the basis of this thrust as being an interaction between the escaping air and the air outside the balloon which is patent nonsense and proves he has misunderstood the principle of action and reaction! If he had said the air escapes due to a movement from a high pressure area to a low pressure area while the reaction occurs in the opposite direction to this airflow I might have forgiven him but ascribing the reaction to an interaction of this flowing air and the air outside the balloon is just plain wrong!

Can I expect to learn anything useful from somebody who makes such an elementary mistake. I wil soldier on but am finding his glib simplification of the Brayton cycle irritating as well...

This may be one book I will not finish!

TheGreenAnger wrote: ↑

Fri Aug 12, 2022 1:26 pm

Also started reading 'Jet: The engine that changed the world by Graham Hoyland and have only got to page 15 and have already lost faith in the author who in trying to explain the principle of thrust uses the example of a blow up balloon which when inflated and then released untied will fly around due to Newton's 3rd law as the air escapes. All well and good but he then characterises the basis of this thrust as being an interaction between the escaping air and the air outside the balloon which is patent nonsense and proves he has misunderstood the principle of action and reaction! If he had said the air escapes due to a movement from a high pressure area to a low pressure area while the reaction occurs in the opposite direction to this airflow I might have forgiven him but ascribing the reaction to an interaction of this flowing air and the air outside the balloon is just plain wrong!

Can I expect to learn anything useful from somebody who makes such an elementary mistake. I wil soldier on but am finding his glib simplification of the Brayton cycle irritating as well...

This may be one book I will not finish!

I have read another chapter and to be fair to Mr Hoyland, he has an engaging style when dealing with anecdotes, history and biographical points. I will persevere.

TheGreenAnger wrote: ↑

Fri Aug 12, 2022 2:30 pm

TheGreenAnger wrote: ↑

Fri Aug 12, 2022 1:26 pm

Also started reading 'Jet: The engine that changed the world by Graham Hoyland and have only got to page 15 and have already lost faith in the author who in trying to explain the principle of thrust uses the example of a blow up balloon which when inflated and then released untied will fly around due to Newton's 3rd law as the air escapes. All well and good but he then characterises the basis of this thrust as being an interaction between the escaping air and the air outside the balloon which is patent nonsense and proves he has misunderstood the principle of action and reaction! If he had said the air escapes due to a movement from a high pressure area to a low pressure area while the reaction occurs in the opposite direction to this airflow I might have forgiven him but ascribing the reaction to an interaction of this flowing air and the air outside the balloon is just plain wrong!

Can I expect to learn anything useful from somebody who makes such an elementary mistake. I wil soldier on but am finding his glib simplification of the Brayton cycle irritating as well...

This may be one book I will not finish!

I have read another chapter and to be fair to Mr Hoyland, he has an engaging style when dealing with anecdotes, history and biographical points. I will persevere.

I gave up about 30 pages from the end. The book meandered all over the place, and while some of the factoids highlighted were interesting they did not fit neatly into a good history, or even narrative about the development of the Jet engine. Book in the pile for rendering into pulp by my better half. Not recommended by me.

Wrong? Yes, surely wrong but it would also be wrong to suggest that the air outside the balloon plays no part in the reaction.

Would the balloon in a vacuum have the same thrust?

Why does a jet boat go faster when the nozzle is above the water line?

Not really my area of expertise so you may feel an inclination to comment.

Biography of Victoria Wood. Interesting but far, far too much detail of exactly who was in which sketch, etc.

John Hill wrote: ↑

Wed Aug 24, 2022 6:17 am

Wrong? Yes, surely wrong but it would also be wrong to suggest that the air outside the balloon plays no part in the reaction.

Would the balloon in a vacuum have the same thrust?

Why does a jet boat go faster when the nozzle is above the water line?

Not really my area of expertise so you may feel an inclination to comment.

The pressure differential between the air in the balloon and the vacuum of space would be greater than, say at ISA sea level thus the balloon in space would have would have a fractionally greater thrust duration but not necessarily greater thrust due to the way the air escapes in a vacuum, but the underlying principle of Newton's 3 Law is still the basis for the thrust and the air in the balloon is not reliant on anything to push against save for the walls of the balloon, or the nozzle, itself to produce thrust. Pressure differentials and the shape of the nozzle do make a difference but not in the way the author of the book implied.

It is an interesting area and it is true that the size and shape of the rocket nozzle is important vide. the Aerospike engine.

The purpose of any engine bell is to direct the exhaust of a rocket engine in one direction, generating thrust in the opposite direction. The exhaust, a high-temperature mix of gases, has an effectively random momentum distribution (i.e., the exhaust pushes in any direction it can). If the exhaust is allowed to escape in this form, only a small part of the flow will be moving in the correct direction and thus contribute to forward thrust. The bell redirects exhaust moving in the wrong direction so that it generates thrust in the correct direction. Ambient air pressure also imparts a small pressure against the exhaust, helping to keep it moving in the "right" direction as it exits the engine. As the vehicle travels upward through the atmosphere, ambient air pressure is reduced. This causes the thrust-generating exhaust to begin to expand outside the edge of the bell. Since this exhaust begins traveling in the "wrong" direction (i.e., outward from the main exhaust plume), the efficiency of the engine is reduced as the rocket travels because this escaping exhaust is no longer contributing to the thrust of the engine. An aerospike rocket engine seeks to eliminate this loss of efficiency.

I am reading Robert Harris's "Cicero". To those who think Bojo's Government is a first for possessing a complete lack of honesty and integrity and being utterly devoid of a single grain of common sense, the Collapse of Rome offers a cautionary tale. Sadly I can't see anyone having the courage to dispose of Johnson by the method used on Julius Caesar.

OFSO wrote: ↑

Sun Aug 28, 2022 6:15 pm

I am reading Robert Harris's "Cicero". To those who think Bojo's Government is a first for possessing a complete lack of honesty and integrity and being utterly devoid of a single grain of common sense, the Collapse of Rome offers a cautionary tale. Sadly I can't see anyone having the courage to dispose of Johnson by the method used on Julius Caesar.

Die bloedige hand erf nooit! (Was it Hugo Grotius who said that?)

Well it is not like Johnson had signed a will, in any case he is a dishonorable man whose word or signature means nothing.

OFSO wrote: ↑

Sun Aug 28, 2022 6:15 pm

I am reading Robert Harris's "Cicero". To those who think Bojo's Government is a first for possessing a complete lack of honesty and integrity and being utterly devoid of a single grain of common sense, the Collapse of Rome offers a cautionary tale. Sadly I can't see anyone having the courage to dispose of Johnson by the method used on Julius Caesar.

I refer you to posts #122-125 a few years ago in this thread

I envy you

Sadly I can't see anyone having the courage to dispose of Johnson by the method used on Julius Caesar.

Although I do wonder if Boris has not by now uttered those famous words said by Kenneth Williams at the start of a certain Carry On movie....

Given whats happened to poor Salman I shall be re reading 'East West', delightful collection of small stories....

Given whats happened to poor Salman I shall be re reading 'East West', delightful collection of small stories....

It's at the end. "Infamy, infamy, they've all got it infamy.... "

Just finished this book...well on audible---I listen wile flying/driving.

Great book explaining the world of professional kitchens with advice on what not to order when.....and also how to improve your cooking.....

.

G~Man wrote: ↑

Mon Aug 29, 2022 4:57 pm

Just finished this book...well on audible---I listen wile flying/driving.

Great book explaining the world of professional kitchens with advice on what not to order when.....and also how to improve your cooking.....

.517Ga5gjDqL._SX326_BO1,204,203,200_.jpg

Read that years ago and bought copies for my West and East coast American cousins - I was with them in the States in May and they both mentioned how much they had loved and reread it

Just finished “River of the Gods: Genius, Courage, and Betrayal in the Search for the Source of the Nile” by Candice Millard.
Biography of Richard F. Burton centered around his search for the source of the White Nile.

For something lighter, I have "Young Frankenstein: A Mel Brooks Book: The Story of the Making of the Film"

PP

I am slowly working through "Through The Overcast" by Assen Jordanoff gathering grounding for our Link Trainer simulator, simulator experience.

Just finished "The Black Watch : the men who fly America's secret spy planes" / Ernest K. Gann.
Not one of his best. It seemed like he threw out a bunch of wordy descriptions of people and events.
I would have been happier reading a synopsis.

PP

Segued directly from Herb McCormick's,"As Long as It's Fun: The Epic Voyages and Extraordinary Times of Lin and Larry Pardey" into a book, partly about one of the villains they bumped into in their travels, an American named Don Sorte who had been partly instrumental in setting up the Canadian company responsible for the manufacture of the Pisces submersible, whose role in the rescue of Roger Mallinson and Roger Chapman from a potential watery grave was canvassed here earlier.

viewtopic.php?p=315465#p315465

https://montecristomagazine.com/communi ... submarines


Pisces submersible


Don Sorte was a bit of an enigma in many ways, and not a very nice guy, when all is said and told, but an interesting person nonetheless before his laissez faire attitude to sailing the 7 seas led to disaster, and tragedy, and whose brief encounter with the Pardey's was to leave a lifelong bad memory for both of them.

I just attended the wedding of Craig's daughter this weekend---she married my SO's nephew. I got to spend about 20 minutes talking with Craig yesterday, he is fascinating, and I just bought his book to read:

Because Our Fathers Lied: A Memoir of Truth and Family, from Vietnam to Today

. Craig McNamara came of age in the political tumult and upheaval of the late ‘60s. While Craig would grow up to take part in anti-war demonstrations, his father, Robert McNamara, was John F. Kennedy's Secretary of Defense and the architect of the Vietnam War. This searching and revealing memoir offers an intimate picture of one father and son at a pivotal period in American history.

Before Robert McNamara joined Kennedy's cabinet, he was an executive who helped turn around Ford Motor Company. Known for his tremendous competence and professionalism, McNamara came to symbolize "the best and the brightest." Craig, his youngest child and only son, struggled in his father's shadow. When he ultimately fails his draft board physical, Craig decides to travel by motorcycle across Central and South America, learning more about the art of agriculture and making what he defines as an honest living. By the book's conclusion, Craig McNamara is farming walnuts in Northern California and coming to terms with his father's legacy.

Because Our Fathers Lied tells the story of the war from the perspective of a single, unforgettable family. But it’s more than a family story—it’s a story about America.