Talk:Gliding flight/Archive 1

Glilding

Typographical error found. After the first sentence that defines the term, Lift, the second sentence states: "There ate five principle types of lift." the sentence should say "There are five principle types of lift."

You saw that, but missed that there are only four listed. The ref says five, but only gives four. WP:NOR says we can't fix this! Dhaluza 04:10, 20 June 2007 (UTC)

Stratospheric waves, ie the Perlan project, would be another source of lift. Also, the Morning Glory cloud, which sometimes occurs on the gulf of Carpenteria in Australia, would be another unique lift source. —Preceding unsigned comment added by 216.141.228.112 (talk) 22:26, 25 August 2008 (UTC)

Risk of duplication

Recent edits run the risk of unnecessarily duplicating information already adequately covered elsewhere. If the same material used used multiple times under every conceivable heading, then Wikipedia will become very difficult to maintain. No doubt these changes were made with the best of motives, but on this occasion were counter-productive. Please use Talk Page before making a major change to the scope of an article.

No, I don't have to. I refuse to discuss this with you in particular. In my opinion you've abused your editing and discussion privileges too many times.- (User) Wolfkeeper (Talk) 11:20, 4 February 2009 (UTC)

As the gliding article states, soaring is the correct term to use when the craft gains altitude or speed from rising air. Gliding (flight) is a descent, whereas gliding the sport uses rising air. JMcC (talk) 08:50, 4 February 2009 (UTC) & JMcC (talk) 09:12, 4 February 2009 (UTC)

Soaring is something done as part of gliding; and gliding does not necessarily imply descent only lack of power. How can you get such basic english words wrong? Gliding in general is not a sport, and is performed by a wide range of aerodynes, including birds and the space shuttle. Who are you trying to fool with this crap? Nobody is buying your attempts to redefine the English language to make gliding something only done by sailplanes.- (User) Wolfkeeper (Talk) 11:20, 4 February 2009 (UTC)

The wikipedia is not about wikiality; your inability to grasp this will eventually get you booted off here.- (User) Wolfkeeper (Talk) 11:20, 4 February 2009 (UTC)

Would you clarify the following:

• Do you agree that a glide is an unpowered descent by flying machine or animal?
• Does the title Gliding (flight) suggest that the article is about this mode of flight as practised by the Space Shuttle, birds and a wide range of aerodynes?
• Is rising air a meteorological phenomenon?
• Is there any reason why these two subjects should appear in one article?

JMcC (talk) 15:52, 5 February 2009 (UTC)

I don't agree that glide is the same as unpowered descent, although unpowered descent is a part of gliding. (Actually unpowered descent is a misnomer anyway, there's always a source of power, usually potential energy).

I believe yes it does. I can provide buckets of references to its use on myriad types of aerodynes, including birds. Really trivial to do.

Rising air is a meteorological phenomenon but its use and locations where it can be found is squarely part of gliding flight.

Sources of rising air are important for gliding as they are employed by gliding aerodynes, particularly gliding birds as well as sailplanes and hang gliders. The locations and reasons for these meteorological conditions are highly relevant to gliding flight.- (User) Wolfkeeper (Talk) 16:24, 5 February 2009 (UTC)

I agree that a glide is descending flight by a machine or animal as the result of zero power, or very low levels of power. (In WP, glide means whatever the cited sources say it means.)

The title, and the opening paragraph, suggest the article is about unpowered flight as observed in birds, some animals, and aircraft, particularly specialist aircraft such as sailplanes, hang gliders and paragliders.

Rising air is a meteorological phenomenon. I am a little uncomfortable with rising air described as lift (and therefore equated with aerodynamic lift) but if that is the terminology used in the cited source, so be it.

I'm not certain which are the two subjects. The sports of gliding, soaring etc. are a sub-set of gliding flight. All sailplanes (aka gliders) engage in gliding flight, but not all gliding flight is practiced by sailplanes. eg The occupants of the Gimli glider were not engaging in sport.

The sport of gliding deserves its own article, separate from the technical article describing gliding flight. Dolphin51 (talk) 22:12, 5 February 2009 (UTC)

The other thing is that an aircraft can be quite reasonably be considered to be descending through the air-gliding-as it is in fact rising. Since in soaring flight, the air is rising, the airspeed is still downwards, but the overall vehicle speed may be upwards. I personally think that gliding is an airspeed thing, rather than true rate of climb.- (User) Wolfkeeper (Talk) 22:50, 5 February 2009 (UTC)

I agree that in soaring flight the airspeed is downwards but the speed relative to the ground is upwards. However, in many maneuvers in gliders the airspeed is upwards even though the air mass is stationary. Sadly, these upward maneuvers only last a short time before the glider runs out of kinetic energy! I think that gliding is neither airspeed nor rate of climb — it is the absence of thrust.

In many situations the engines of a powered aircraft are developing a small amount of thrust but the aircraft is performing very similar to the way it would with zero thrust, so this can also be considered gliding flight, and the principles of gliding flight apply. For example, in steady gliding flight at an angle of $\theta$ to the horizon:

drag = weight x sin$\theta$

lift = weight x cos$\theta$ Dolphin51 (talk) 00:43, 6 February 2009 (UTC)

Yes, that seems to me to be correct. Gliding seems to occur when an aerodyne has an absence of thrust; that would seem to be a more accurate restatement of 'unpowered flight'. We would ideally need a reference for that, although if people agree that that's essentially what is meant by the term 'unpowered flight', then it would be easy to do that from any of the normal references.- (User) Wolfkeeper (Talk) 02:12, 6 February 2009 (UTC)

Incidentally, Paul MacCready achieved human powered flight by calculating the power needed for a hang glider (a significant fraction of a kilowatt IRC) and then worked to design an aircraft to the point where a person would be able to exert that for an extended period (a couple of hundred watts or so); so the fact that gliders aren't (technically) unpowered actually mattered(!)- (User) Wolfkeeper (Talk) 02:12, 6 February 2009 (UTC)

I'm not sure about low thrust, although that might be considered a 'powered glide' or something. I think I've seen that term in use somewhere, or something like it.- (User) Wolfkeeper (Talk) 02:12, 6 February 2009 (UTC)

Wolfkeeper has set up a parallel article called Gliding (flight). It must be contrary to Wikipedia's policies to have parallel articles reflecting the separate views of editors. There should be an article about the glide as mode of flight. This could cover the physics of the forces, and the glide ratio. However Wolfkeeper has included material on rising air and launching in the new article. These are nothing to do with the mode of flight of aircraft, birds and mammals. Rising air is a meteorological phenomenon that is only exploited in the three air sports: gliding, hang gliding and paragliding. (References to three separate world championships could be added here). The glides of the Space Shuttle, flying squirrels and stricken airliners do not use rising air. The new article is therefore can only duplicate the sports articles. This article is trying to cover three sports at the same times and so risks confusion. There was an article about rising air called 'lift (soaring)' which covered this subject, but this has been merged into this new article. The restoration of a separate article on rising air could be useful in articles on raptors, which would otherwise be linked to an article that included winch launching. An article purely about the glide as a mode of flight would also be useful in other articles on animal locomotion. On one occasion I attemted to remove the duplicating aspects of gliding (flight) but I have been told that I am abusing my editing privileges. Your analysis and your advice would be gratefully appreciated. JMcC (talk) 09:10, 7 February 2009 (UTC) & JMcC (talk) 10:03, 7 February 2009 (UTC)

Gliding and soaring is employed by a very wide variety of creatures including, but not limited to, birds (sea birds, raptors, carrion feeders), flying fish, gliding mammals, bats and possibly some insects as well. Come to think of it, even some spiders do a form of soaring. I therefore find Jmcc150's comments completely inaccurate on every major point. His complete desperation to include information on sports gliding of only sailplanes to the detriment of the wikipedia, and to systematically minimise and remove every other form of glider in case it affects his glorious articles in any way at all, is a clear violation of NPOV and is not defensible.- (User) Wolfkeeper (Talk) 13:28, 7 February 2009 (UTC)

I completely agree with Wolfkeeper's first two sentences. That is precisely why the one thing I am not trying to do is restrict this article about gliding flight to a human activity such as the sport of gliding. A generalised article about gliding flight would be a useful link in articles about animal locomotion as well as non-soaring aircraft. When readers about flying squirrels, stricken airliners or the Space Shuttle want to know more about a glide, they will will be puzzled to read through material about rising air and launching. The total scope of this article is a human activity, namely the recreation of humans flying soaring aircraft. For the same reason I also think that generalised material about rising air is a totally different topic, that would be useful in articles about birds such as raptors and seabirds. True, there are references to animals but this merely creates an even more confusing mixture. In short the scope is too broad and so tries to cover three things at once: rising air, gliding flight and a human recreation. JMcC (talk) 19:19, 7 February 2009 (UTC)

The scope of this article is a standard topic of aviation. The idea that we should descope topics because Jmcc150 believes others might get easily confused over minor points is not something that I am aware is ever done in the wikipedia, and I would like to know what policy or guideline that would be performed under. I certainly do not think that any reasonable reader would be confused anyway, and I am not concerned with the unreasonable ones.- (User) Wolfkeeper (Talk) 20:05, 7 February 2009 (UTC)

Just to summarise my position, I suggest that the current scope of this article is three standard topics in aviation. Two of which require articles and one of which is covered elsewhere. It seems that Wolfkeeper and I will forever differ. I contend that 'gliding flight' is just a descent. Interestingly, the article on the sport of gliding, even in the time before Wolfkeeper became involved, also makes this assertion, so I am not saying this purely to make my point here. I do not want to reduce the information in Wikipedia, just put it in its rightful place. JMcC (talk) 16:57, 9 February 2009 (UTC)

gliding, soaring, unpowered winged flight - compromise toward a guideline?

This discussion seems to have spilled over to Wikipedia Talk:WikiProject Gliding#Gliding. In the discussion we have determined that there is an issue of different understanding of the term gliding between the US and UK. In the US, gliding is any unpowered winged flight, while soaring is the sport of flying sailplanes. In the UK, gliding is the term for the sport of flying gliders. It would be useful and constructive to try to reach consensus and write a guideline that everyone can live with on how to use these terms in our international community on Wikipedia. Ikluft (talk) 19:19, 12 February 2009 (UTC)