Slips, Skids, and Spins Explained

In this video I explain slips, skids and spins associated with flying airplanes. More specifically, I talk about the usefulness and benefits of slips, the dangers of skids, and finally, how skidding turns can lead to deadly spins. In regards to slips, I discuss side slips and forward slips, where the former is used for making crosswind landings and the latter for loosing altitude quickly and safely. I also discuss how skidding turns, particularly when done on base to final turns, can lead to deadly stall spin accidents. And most importantly I talk about how to avoid getting in a stall, spin situation.

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Many instructors explain that "fuselage blanking the wing" causes that wing to stall". Not true (OK, indirectly slightly true). Exceeding stall AOA is what causes the wing to stall, and blanking doesn't change the AOA. What actually happens in a SLIP is that the high wing usually has down aileron (to hold that bank angle due to yaw and, yes, "blanking". But mostly yaw-roll coupling). The down aileron changes the local chord line so that area of the wing now has a higher decalage angle (difference between chord line and longitudinal axis of the fuselage) and thus, a higher AOA. And the low wing has up aileron and a lower AOA.

Opposite with a SKID: low wing is usually kept from over banking (due mostly to yaw-roll coupling, and a little blanking) with down aileron, so the low wing stalls, and the plane rolls upside down.

Stalling in the pattern is bad, period. A slip is a bit more forgiving because the high wing stalls first and the plane rolls towards wing level, giving you a little more time to correct the situation. It also reduces the load factor and as a result, AOA. Stalling in a skid, everything gets worse real fast. You've seen airshows where the Piper Cub does a "flat turn" keeping the wings level and using full rudder to "skid" around a 360 degree turn? Well, that's about the only use there is for a skid, and leave that to the pros.

To clarify some of the above aerodynamics: Yaw-roll coupling, or "proverse roll" is a result of the wings dihedral. When you yaw the plane and cause the relative wind to shift from on the nose to one side or the other, the forward wing sees a higher AOA and the trailing wing sees a lower AOA, thus the plane will tend to roll in the same direction of the rudder input (proverse). If you had anhedral (wings angled down, opposite of dihedral), it would roll opposite the rudder input, or adverse roll. These terms should be somewhat familiar since pilots should be aware of "adverse yaw" caused by differential aileron drag when ailerons are displaced when rolling (that's why airplanes have rudders to correct this, provided the pilots actually use the rudder). Anyone who is still awake, sorry about getting technical.

Ben
26, 000+ hrs
USAF/Major Airline Capt/Aerobatic & Tailwheel Instructor/ CFI/II/MEL/Movie/TV pilot/Sailplane racer/Aero engineering and flight test.

[happysawfish]

Thank you Mr. Falcon. This topic cannot be explored too much.

[davidnapper]

Excellent video. As a student pilot this really helped me. I need to know the "why's" and recently during forced approaches I am slipping in a turn and couldn't reconcile why that was ok but the dreaded base to final wasn't. This video cleared it up so quickly

[mms]

Great video but it would be more helpful for beginners if you slow down a bit and have a bit more dramatic gesture with the small plane so it would be abundantly clear for a novice

[Lithiumbattery]

this is the best explanation, thank you 🌟⭐🌟⭐🌟

[TravelwithfahadAhmed]

Very informative video, Thanks for sharing friend ♥️🌹🌷🇵🇰🌹

[aidsowen]

Awesome video! Thank you for sharing your knowledge with all of us ❤

[RazvanAdrianPrata]

Many thanks for sharing your knowledge! Subscribed

[njbpaul]

Thanks for this information. it was clear and to the point . a new subscriber