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Flash
301000.  Sun Mar 23, 2008 6:21 pm Reply with quote

Kingbarney - thanks for your contributions, but I think I should say that I sometimes find them difficult to understand either because they are very abbreviated or possibly because they contain a typo. The post above is an example - are you simply agreeing with mckeonj, or adding information, or disagreeing, or what?

 
rioconnection
303123.  Wed Mar 26, 2008 9:55 am Reply with quote

Alberto Santos Dumont is credited with making "the first public European flight of an airplane in Paris on 23 October 1906. That aircraft, designated 14-bis or Oiseau de proie (French for "bird of prey"), is considered by Santos-Dumont supporters to be the first to take off, fly, and land without the use of catapults, high winds, launch rails, or other external assistance."

see: http://en.wikipedia.org/wiki/Santos_Dumont

 
Kingbarney
303309.  Wed Mar 26, 2008 1:37 pm Reply with quote

Flash wrote:
Kingbarney - thanks for your contributions, but I think I should say that I sometimes find them difficult to understand either because they are very abbreviated or possibly because they contain a typo. The post above is an example - are you simply agreeing with mckeonj, or adding information, or disagreeing, or what?


AH yess I have my typo rate has increase lately must all that cider.....

Anyway I was questioning whether Flying Squirrels flew in the same way a bird does

 
mckeonj
303368.  Wed Mar 26, 2008 3:04 pm Reply with quote

There are many modes of flight; the two most popular are flapping (which includes buzzing) and gliding; others are para-gliding, shearing and 'ballooning'.
Flapping and gliding are what birds and insects mostly do.
Gliding and para-gliding are what squirrels and sycamore seeds do; also man-made aircraft mostly power glide.
Shearing is done by some birds (the shearwaters), flying fish, and the Russian Ekranoplan.
'Ballooning' is what some spiders do; they pay out a silk line into the wind, and when enough line is out they get lifted up and taken elsewhere.
I don't know the 'correct' technical terms for these modes, and I guess that aeronautical experts and zoologists have their own terms.

 
PDR
303384.  Wed Mar 26, 2008 3:41 pm Reply with quote

gerontius grumpus wrote:
The Hindenburg was designed for Helium instead of Hydrogen but the USA, which had a monopoly in Helium production, was prevented form exporting the gas by the Helium control act, 1927.
This restriction was enacted to prevent foreign powers using Helium for military purposes.


True, but now we understand the actual cause of the crash it is clear that it would still have happened even if the Hindenburg had used Helium as the lifting gas. So the american witholding of helium wasn't a causal factor in either the crash or the casualties.

In fact now I think about it this could be a really good QI question - "How many people died in the Hindenburg crash as a result of the americans witholding the helium?" (the answer is "none").

QALOPKT(BTSDGAS),

PDR

 
PDR
303404.  Wed Mar 26, 2008 4:22 pm Reply with quote

markvent wrote:
Q: Who invented the first flying machine

K: Orville & Wilbur Wright

A: Well .. it's something of a can of worms .. what do you mean by first, what do you mean by flight, what do you mean by machine, are we talking powered or not, manned or not ? as I say a big old can of worms...


Ooh, good question, and one which I suspect could not be resolved definitively without the aid of a time machine because all of the potential contenders preceded the age of mass communication (some by a millenium or two).

Whilst there were/might have been/could well have been [take your pick] others who succeded in achieving sustained, powered, man-carrying, heavier-than-air flight without external energy input, aeronautical engineers would generally feel that the Wrights were the ones who deserve the credit for showing the way. Why? Well they were the first to achieve solutions to ALL the enabling technologies, and because they actually knew what they were doing - their designs were the outcome of sound science and engineering rather than empirical trial-and-error.

The Wrights built a wind tunnel, conducted experimental measurements and derived theories based on the results. This meant that they knew their machine would actually fly rather than having to try to fly it as a shot-in-the-dark.

The Wrights (correctly) identified that power-to-weight ratio was a key issue, and that none of the available powerplants were light enough. So they designed and developed their own ultra-light 4-cylinder 4-stroke engine - an engine whose power-to-weight ratio was more than twice as good as anything else around at the time.

The Wrights were the first ones to give serious consideration to the subject of stability & control. They examined the work of Otto Lillienthal and realised that he died because his machine had no effective controls. Their designs had positive control about all three axes (they "invented" roll-axis control, which had been ignored by all their predecessors). The original designs up to the Flyer III were unstable in pitch because the Wrights' experiments had shown that whilst this made flying very hard work it gave powerful and rapid pitch response, which they felt was a price worth playing. Their later more powerful and faster designs needed more stability, but by this stage the wrights knew enough to be able to provide it (by moving the centre of gravity forward by about 18 inches).

So the Wright machines didn't merely fly in an uncontrolled manner - they were controllable, practical flying machines with plenty of growth potential to allow for bigger things. The original machine that claimed the first flight was actually fitted with a less powerful engine because the better engine was under rebuild at the time (after a stuck valve had burned its seat). The catapaulted flight was intended to prove the control system and the basic viability of the design, so that the rebuilt engine would allow for sustained flight at a later date. They wanted to get this work done while they had a "weather window" because once the wind starts in Daytona you can be hunkered down for weeks waiting for the next calm day.

So I would suggest that the dates are a matter of irrelevance - the Wrights still deserve the credit for originating the practicable, controllable, developable aeroplane, and for originating Aeronautics as a real branch of engineering science.

0.02 supplied, YMMV,

PDR

 
Kingbarney
303409.  Wed Mar 26, 2008 4:33 pm Reply with quote

mckeonj wrote:
There are many modes of flight; the two most popular are flapping (which includes buzzing) and gliding; others are para-gliding, shearing and 'ballooning'.
Flapping and gliding are what birds and insects mostly do.
Gliding and para-gliding are what squirrels and sycamore seeds do; also man-made aircraft mostly power glide.
Shearing is done by some birds (the shearwaters), flying fish, and the Russian Ekranoplan.
'Ballooning' is what some spiders do; they pay out a silk line into the wind, and when enough line is out they get lifted up and taken elsewhere.
I don't know the 'correct' technical terms for these modes, and I guess that aeronautical experts and zoologists have their own terms.


I would image you could you have a question like what is flight ? on the show

 
Southpaw
303957.  Thu Mar 27, 2008 8:19 am Reply with quote

A klaxon-worthy fact is that Chuck Yeager was not the first person to break the sound barrier. It is thought that George Welch, a civilian test pilot for North American Aviation, actually achieved it one week before Yeager.

The company was instructed not to attempt to break the sound barrier before Yeager's X1 project, by the then Secretary of the Air Force. However, Welch ignored this order and on October 1, 1947 he entered a steep dive from 35,000ft in his F-86 Sabre. During the dive, he observed symptoms compatible with Mach jump, and a sonic boom was heard at the test base. Some days later, on the same day as Yeager's flight, Welch attempted a supersonic dive again, this time from 37,000ft, executing a full power 4g pull out. Yeager broke the sound barrier 30 minutes later.

The claim is disputed because of a lack of a verifiable measurement and because the speed was achieved during a dive as opposed to level flight.

There is further speculation that the sound barrier was actually broken by a Luftwaffe pilot in 1945, Hans Guido Mutke, flying the groundbreaking (not literally in this case) Messerschmitt 262 jet fighter, though this is again disputed, not least because Messerschmitt testing concluded that the aircraft would become uncontrollable at speeds over Mach 0.86 and would go into an unrecoverable nose-trim dive.

 
gerontius grumpus
304928.  Fri Mar 28, 2008 5:04 am Reply with quote

PDR wrote:
gerontius grumpus wrote:
The Hindenburg was designed for Helium instead of Hydrogen but the USA, which had a monopoly in Helium production, was prevented form exporting the gas by the Helium control act, 1927.
This restriction was enacted to prevent foreign powers using Helium for military purposes.


True, but now we understand the actual cause of the crash it is clear that it would still have happened even if the Hindenburg had used Helium as the lifting gas. So the american witholding of helium wasn't a causal factor in either the crash or the casualties.

In fact now I think about it this could be a really good QI question - "How many people died in the Hindenburg crash as a result of the americans witholding the helium?" (the answer is "none").

QALOPKT(BTSDGAS),

But would all of those people have died without the fire?

PDR

 
PDR
305502.  Fri Mar 28, 2008 1:38 pm Reply with quote

gerontius grumpus wrote:

But would all of those people have died without the fire?


One of the great misconceptions. Firstly those people who were burned in the Hindenburg crash were burned by ignited engine fuel (a neutrally bouyant gas) and not by the hydrogen. Whilst the hydrogen did burn, it went pretty well straight up and burned ABOVE the airship (you can see this clearly on the film). People were in the lower part of the hull, well away from the flames in the gas cells.

Secondly the hydrogen didn't cause the fire - there would still have been both a fire and a crash if the airship's gas cells had been filled with helium (or even nitrogen for that matter). This was definitively established about 10 years ago. The cause of the fire was the thunderstorm through which she flew. The airship was designed to cope with thunderstorms through good electrical bonding throught the structure, but an oversight had left some laced-in access panels un-bonded. As a result the electrical currents flowing allowed a large potential to develop between these panels and the rest of the structure. This let to arcing across the lacing chords, which (in turn) ignited the outer canvas covering of the airship. This canvas had coats of protective laquer and paint, partly to shrink and tauten the covering, partly to provide it with pretection from UV light and partly to (again) provide an electrically conductive skin to ensure good bonding. The base laquer was nitro-cellulose dope (as used on most fabric covered aircraft of the day). The anti-UV layer was read-oxide) primer (again, as used on most aircraft of the day). But the electrically conductive layer was a suspension of aluminium dust in a laquer medium.

Red-oxide primer is mostly comprised of iron oxide (rust). Iron oxide and aluminium, if heated together, burn extremely vigorously - it's called the "Thermite Reaction" (google it). It also burns in the absence of oxygen, which is why it's used for things like underwater welding work.

So the fire was in the skin of the airship. It was vigorous and unextinguishable. Once started, the fire would rupture the gas cells and the craft was going down - the use of hydrogen only added to the overhead illumination and had no material effect on the accident or the casualties.

And as a final twist - examination of papers in the Smithsonian which were taken from German archives after WW2 showed that the Germans had actually worked this out for themselves. There are papers describing experiments subjecting samples of identically treated canvas to electrical arcs, and others proposing alternative fabric treatments to eliminate the problem.

PDR

 
Leith
305666.  Fri Mar 28, 2008 5:49 pm Reply with quote

According to Adam Hart-Davies (on 'What The Victorians Did For Us') and Wikipedia the first unmanned powered flight took place in 1848.

William Samuel Henson and John Stringfellow's Aerial Steam Carriage was designed to carry passengers. It never achieved this but did manage to fly short distances inside a hanger.

 
TwistedByKnaves
549235.  Wed May 06, 2009 4:32 pm Reply with quote

Is an airship actually lighter than air?

 
Dr. Know
549239.  Wed May 06, 2009 4:33 pm Reply with quote

Surely that's impossible? What with all the metal bits.

 
Sadurian Mike
549241.  Wed May 06, 2009 4:36 pm Reply with quote

The gas is there to counter the weight of the structure.

If you have gas providing a ton of lift then your airship superstructure can weigh close to a ton and still float.

 
Posital
549272.  Wed May 06, 2009 5:04 pm Reply with quote

TwistedByKnaves wrote:
Is an airship actually lighter than air?

Yes - it's the Archimedes principle. The airship weighs less than the air it displaces.

 

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