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Phugoid mode and "porpoising" mode are different ones. The first is a long period one, and the second is a short period movement as the change in AoA is. The airplane has three modes of oscillation. (CFG)
I added the "too technical" comment primarily because I had no idea what a "singlet" is. Most of the article is a little beyond the average reader, I think, but it's a fairly esoteric topic. Still, it could be made more accessible.--andersonpd 22:55, 26 October 2005 (UTC)[reply]
I, as an engineer but not an aeronautical one, believe I have grasped the concept. A picture would have helped.
Since it is angular momentum that keeps the model from leveling off before it stalls or loops, it is not likely that similarly trimmed piloted aircraft, with the pilot inactive, never act like these models. David R. Ingham (talk) 18:19, 8 February 2008 (UTC)[reply]
The sentence "The use of a canard in aircraft design exploits this phenomenon and ensures that the main wing is prevented from stalling" is unreferenced and almost certainly misleading. As I understand it, the canard stalls first because it is necessarily at a higher angle of attack than the main wing - resulting in a pitch-down movement which then prevents the main wing stall. This has nothing to do with the phugoid cycle, where as our article makes clear, the angle of attack hardly varies, and stalling isn't an issue. If someone can find a specific reference to canards and the phugoid cycle, indicating that there is some specific consideration, it can be added to the article, but for now I'm removing the unreferenced sentence. 86.161.118.143 (talk) 15:04, 15 December 2013 (UTC)[reply]
Phugoids are positive feedback loops that typically get worse and worse exponentially.
The NASA source cited in the article (cite number 6) even says in the same paragraph that phugoids tend to double every cycle.
Searching other sources online, though few, all call it a positive feedback loop that is one that exponentially increases to destruction without intervention.
The whole article is written like they are somehow stable or self-correcting, however there is nothing to show that, no sources cited, and no other sources that can be found online. I also asked an aerospace engineer who has designed several large commercial aircraft and his assessment was also contrary to this article.
This article seems to be the only one on the internet that suggests phugoids are stable and/or self correcting, with the only citation to that effect being a book from the 60s that's conveniently not accessible.
All the other sources in this article suggest that phugoids are exponentially growing to the point of destruction of the system. Nabeel_co (talk) 20:36, 23 November 2021 (UTC)[reply]
