Factors Affecting Stall Speed

by Jason Schappert

What factors can increase or decrease our stall speed? In this video we’ll look at a few things you may not have thought of in regards to changing our aircraft stall speed. As always after the video be sure to leave me a comment with some of your ideas from the video.

David

I enjoyed your Stall Speed discussion. I would have appreciated if you gave your definition of critical angle of attack. ( maybe it was in an earlier video? )
Jason C

Other factors: t/o weight, air density, vertical acceleration (?), wind shear
ashok

weight and load factor affect stall speed????
Marcus H

These factors don’t necessarily increase your stall speed, but I’ve heard it’s recommended to add 5 KIAS on approach in gusty or turbulent winds.
Mhlansdell00

I’ve heard a lot of conflicting information about stalls, particularly high speed stalls. The Air France crash a couple of years ago resulted in a stall at close to 700k. I’ve been told that at fl 36.0 the airspeed to keep the equipment in the air is a range of 20 k or so. Please explain that if you’re familiar with the concept. Also, watching high performance, over powered aircraft, there are exceptions to the attitude rule your referring to. It seems you can over power a stall or does the aircraft just become a rocket ship at that point?
Ron M

It is not the bank angle that increases stall speed it is the wing loading. A 60 degree bank while maintaining altitude will increase stall speed. However, a 60 degree bank in a descent (1 g loading) will not increase stall speed.
Dave

Based on the formula for lift, the TAS where the stall occurs increases with altitude because of the lower air density.
Sebutler

I would argue that an aircraft always stalls at the same angle of attack in a particular configuration. Adding flaps, while generally decreasing the stall speed, may or may not change the critical angle of attack. Also, from looking at some of the other comments below, you probably should have specified IAS.
Philjeter

uncoordinated turns.
Abrarmetro1

hello well Jason ur explaining all the stuff in a very good way kp it up… well man i m very weak in navigation and its basic concepts do u have any specific lectures on it? it would b a great favor frm ur side to me in my practical field.
Mark C.

This is a fundamental flaw in the way the concept is taught. Instead of teaching stall speed, this should be taught as stall ANGLE, and then AOA should be correctly explained as the angle between the wing and the relative wind. Then, when introducing all the variables which can affect stall, the discussion shouldn’t be about speed, but how each factor affects AOA or the critical AOA, e.g., flaps change the shape of the airfoil and raise the critical AOA, dirt or damage change the shape of the airfoil and lower the critical AOA, etc. Once people grasp the idea of the angle of the wing to the relative wind, they can understand how stalls occur in situations such as turns, or the big pilot killer, pulling out of a dive after buzzing the field.
Steve

Of course, we can get deep into aerodynamics on this, but the real thing a private pilot needs to become aware of is the relationship between relative wind, angle, and the operating limitations put on a specific aircraft. How does loading affect the performance? When you start experiencing the flight of the aircraft when you are reaching- but not exceeding- one side of the envelope or another, then the limitations they put on an aircraft start to make sense. Once I took off in a 172 with a heavy load- but not over- and an aft CG- but not out of range- and she raised her nose quickly, but rotation took longer so I noted the speed increase at the point where she left the ground. Also, I noted that I needed down trim, and a lot of it to maintain my climbout speed of 80. I was aware that these factors, while they may or may not have increased my stall speed, they were in fact making a situation where the angle of attack could easily be blown, and quicker too. So I kept my climb angle shallower then normal, and my turn banks shallower then usual. I kept an eagle eye on my pitch and airspeed relationship, as I could see that there was definitely something different. The airplane will never just fall out of the sky, so you have to listen to the changes in the dynamics, and when you are close to one operating limit or another, don’t let the others get out of range.
PEDRO RIVERA ISAAC

your mini courses are very helpfull and you are a good instructor i wish they could be a little more longer i have been learning a lot from it . it like having a home instructor. i wont miss any of your programs (KEEP IT UP JASON) .you are doing a good thing for all student pilots. thanks.
Shunpiker

Hi Jason,

This is a strange comparison, but I was watching crows fly (and land) while I was at work this weekend. I noticed how they would come close to the ground, then increase their angle of attack until they stalled their wings. Then they would “fall” to the ground (only a few inches). It really drove home the fact that AOA is the major component to stalling. Thanks for your time and effort… i really enjoy your input!
Haygrinder

As usual good information! Thank You.
Pablo424

thanks Jason, I enjoyed
Tiptipboy2000

hey jason this a student pilot from the bahamas and i learning how to fly in vero beach florida on other point to is if your airplane is over weight your stall speed is also higher thats my 5cents to that plz reply to me if that added a bug to that video have a happy thanks given from your truly captin major from paris air flight school
Mike Zias

I highly recommend reading: Emergency Maneuver Training by Rich Stowell.

Jason, nice videos.
Larry M. Diamond

If the student is an engineering type who loves formula’s, I show them L = nW L=lift coefficient, n = load factor, W= weight. Then I go to Vst = Vs x square root of the load factor, Vst = stall speed, Vs = stall speed in straight and level and N= load factor. I then talk about how lift equal weight in straight and level. This all comes after explaining about Critical Angle of Attack can happen at any airspeed or pitch attitude. I proceed with what increases load factor. I have them recall what happened in 30 degree banks, 45 degree banks and 60 degree banks. The answer is Load factor changed and increased with each increase in bank. Higher load higher stall speed. I speak on climbing stall speed. You are using power to increase lift and power offsets weight which would lower stall speed in a climb. I then speak on altitude. Higher altitude higher airspeeds higher stall speeds. I even talk about weight with or without the instructor. One passenger, lower weight, lower stall speed. Stick me in the right seat, stall speed goes up. I hope that did not give you a headache. There is a Far Side Cartoon with a teacher in front of a class and the student raises his hand and says, Mr. Osbourne may I be excused, my brain is full.
OMG! PULL UP, PULL UP!

Hi, Jason. Newbie is me.
You mention that banking during a stall increases the stall speed, I believe. Is that because the airflow slips off the wing? and if so, would not fences as on the C182 Wren serve to hold that airflow in place and allow you to bank without losing airflow and thus not allow the stall as soon?
Ken Froese

As an aircraft climbs and altitude increases, what happens to the stalling speed (IAS) of an aircraft? (Increases, decreases, stays the same) Thanks