Talk:Pitch-up

Forward swept wings

I'm fairly sure the statement about forward swept wings is nonsense. With forward swept wings, the roots do stall first, so any resultant roll moment is small, so a spin is less likely (good, but not pertinent to this subject) but the roots on a forward swept wing is further back than the tip (by definition), so the centre of pressure still shifts forward! The tips are still more heavily loaded, so the 2 contributory effects oppose, as rather than reinforce each other, but the stated effect would still tend to cause pitch up & if it is more powerful than the effect of lift distribution (eg. because the tips are washed out, or the wings are elliptical), I'm fairly sure pitch up could certainly still happen (?) — Preceding unsigned comment added by 80.229.172.13 (talk) 23:12, 5 January 2012 (UTC)

Indeed, this page and the page for forward swept wings, contradict each other on this matter. — Preceding unsigned comment added by Broshay (talk • contribs) 20:35, 15 March 2012 (UTC)

Merge of Sabre dance

As suggested by .45Colt, we have two articles on broadly the same topic and they should be merged. Sabre dance is the specific instance of pitch-up, as occurring with the F-100 Super Sabre. It could be merged to a section here, pretty much as a simple paste. This would give one better article overall. There's little interest in the F-100 condition without the broader aerodynamic picture across other aircraft. As the aircraft most affected by it, the F-100 would otherwise be a large omission from pitch-up. Andy Dingley (talk) 10:00, 17 May 2015 (UTC)

Agree. Sabre Dance a specific low-speed nose-up stall inherent in swept-wing aircraft, not unique to F-100 Sabres; "pitch-ups" can occur at any speed in swept-wing craft. So long as these distinguishing points are made clear, merge. Yours, Wikiuser100 (talk) 19:00, 3 June 2015 (UTC)

Agreed and  Done. Klbrain (talk) 11:08, 4 November 2017 (UTC)

Comments from P&W's engineering test pilot in the 1950s

The following comments were inserted in the article Pitch-up on 12 April 2020. Comments of this kind belong on the Talk page so I am pasting them here. I will now delete them from the article. Dolphin (t) 12:52, 21 April 2020 (UTC)

As P&W's engineering test pilot at Edwards AFB during the 1950s I was responsible for flight testing the F-100 and F-101 Voodoo. Due to engine stall problems at higher AOAs, initially our testing (on the F-101) was limited to low AOAs, but as we improved the engine stall problem, we quickly found a new problem. On the F-101 it was called "pitch-up". The nose would rise rapidly, control was lost, and the aircraft would crash also claiming many USAF and McDonnell test pilot lives. I alone survived the loss of control problem by detecting a slight vibration just before the critical AOA. The USAF finally ceased all high AOA testing and asked (only) me to continue with my testing at higher AOAs to obtain more data. Fortunately my tests were successful and the "T-tail" design problem became widely known as the source of the pitch-up problem. From my test data we and McDonnell aircraft and control system designers proposed a substantial modification to the control system adding a feature known as the "stick shaker and stick pusher system", which quickly was successfully installed on F-101 and the F-104 (also with a T-tail. Soon later civil transports were designed with a T-tail and also equipped with the stick shaker system. It worked well for many years ... until the Boeing MAX.

As we have all learned in the last couple years, the control problem on the MAX was more complicated than the simple "T-tail causing pitch-up" we found on the F-101 ... in fact, much more complex! The problem as it stands today (April 2000) involves engines, wing design, tail design, several computer programs designed to correct a variety of flight control problems, pilot training, pilot proficiency, multiple certification issues, both Boeing and FAA management issues, etc.

In my recently completed book, "Knocking on Doors", (sold thru Amazon) these issue are discussed, leading to my conclusion that the entire system of designing, certifying, and operating a new generation of transport aircraft should be reconsidered, with separate designs being offered to airlines in regions with substantially different pilot qualifications in order to minimize operating costs and pilot certification requirements while increasing safety.

Harry Schmidt

Shrewsbury. MA. 508-925-7736