Talk:Stall strips

The role of the stall strip

This article is vague and unconvincing about the role of a wing stall strip. The only citation points to Dale Crane’s Dictionary of Aeronautical Terms. I don’t have access to a copy of this dictionary so if someone can provide the explanatory text related to stall strips I will be grateful.

The caption accompanying the image of the CL-215 includes “… ensuring both wings stall at the same angle of attack despite the propeller wash.” No citation is provided. This is unlikely to be a sound explanation of the role of the stall strip on this aircraft. It would influence the propeller wash over a narrow band of wing span – the article says the stall strip is typically 6 – 12 inches in length. If the stall strip has a beneficial effect in modifying the influence of the propeller wash it would only do so at significant engine power; stall characteristics are also assessed with power off.

Many years ago I had some dealings with the Canadair Challenger CL-600. It has a stall strip mounted on the leading edge of one wing only. The CL-600 is a jet-engine aircraft with aft-mounted engines – no propeller wash in sight! (In 1984 the US Federal Aviation Administration issued STC No. SA99NE to approve removal of the stall strip and modification of the stall protection system.)

It is more likely that the role of the stall strip when installed on the leading edge of one wing only is to prevent the angle of attack reaching too high a value, where pre-stall handling and the stall itself are unacceptable. The single stall strip achieves this by causing a sharp reduction in lift on one wing only, followed by the aircraft rolling sufficiently to prevent any further increase in angle of attack. I don’t have a reliable published source to support this explanation. Dolphin (t) 13:17, 6 July 2021 (UTC)

I have the book here and it says:

stall strip (airplane wing component). A small triangular metal strip installed along the leading edge of an airplane wing near the root. Many airplane wings begin to stall near the tip, in the area ahead of the ailerons. When this portion of the wing stalls, the pilot no longer has good control of the aircraft. To allow adequate control throughout the stall, the small stall strips force the roots of the wing to stall before the tips. When the wing roots stall, the nose of the aircraft drops, and the aircraft recovers from the stall with complete control throughout.

-Ahunt (talk) 16:58, 6 July 2021 (UTC)

Many thanks for your prompt supply of this valuable information. I will think about a way ahead. Dolphin (t) 23:07, 6 July 2021 (UTC)

I propose the following strategy to improve this article.

At present the article contains significant content that is either supported by Crane’s Dictionary of Aeronautical Terms, or is both sound and benign. There is also some content that is unsourced, unlikely to be generally true and probably has no more status than original research. I propose removing the content that is original research.

I pasted the article in its present form into my sandbox. Then I amended it to my suggested form. Readers can see my proposed changes by looking at my diff. All comments welcome. Dolphin (t) 13:30, 9 July 2021 (UTC)

Given the one ref we have, I thought you would be justified cutting it down more, but if you are happy with your sandbox version, then I am fine with that. - Ahunt (talk) 15:04, 9 July 2021 (UTC)

I added one ref on the AA-1 to both this article and your sandbox. - Ahunt (talk) 15:10, 9 July 2021 (UTC)

A function that is not mentioned is that of stall warning. On conversion to the DHC-1 Chipmunk I was briefed that the stall strips were there there to provide turbulent airflow (pre-stall buffet) over the elevator, shaking the control column which it certainly does effectively. The Chipmunk is a spin trainer so it's desirable to have the tip stall before the root which is contra to the purpose given in this article. Just need a source to back this up, possibly in the flight manual/pilot's notes. Nimbus (Cumulus nimbus floats by) 21:58, 9 July 2021 (UTC)

I suspect we should resign ourselves to never finding a reliable published source to explain exactly why a stall strip is installed on a particular type and model of aircraft. Even if we could get access to the Flight Test Report it won't reveal the reason. The FTR shows how the aircraft in its final configuration was found to comply with all the performance and handling requirements - it doesn't have to describe the trials and tribulations that beset the program, or the various attempts at stall strips, vortex generators etc that were tried in an effort to tame the beast. Some explanations are undoubtedly handed down from one generation of instructors to the next generation of students, and they may be accurate in some cases but not in all. Similarly other documents such as the Flight Manual, Pilot Notes don't include an explanation of why aerodynamic fixes such as strips, VGs and strakes are installed, or how the aircraft handled before they were installed. We can be content with a statement that strips are installed to ensure the aircraft complies with type certification requirements. Dolphin (t) 12:23, 12 July 2021 (UTC)

A week has passed and the proposal has been well-aired. I have pasted the content of my sandbox into the article. See my diff. Dolphin (t) 09:54, 14 July 2021 (UTC)

Looks good! Thanks for tackling this. - Ahunt (talk) 12:45, 14 July 2021 (UTC)