slips and skids
- Thread starter Ashneil
- Start date
Mike H
Well-Known Member
in a skid, you have too much rudder in the direction you're turning. in a slip, you have not enough rudder (or even opposite rudder) for the direction of the turn. think of a slip to a landing- you have a bank to the left and right rudder- which by definition is insufficient left rudder for a left turn
ProudPilot
Aeronautics Geek
Think of making a normal turn, so the aircraft is going in a circle. If everything is coordinated, you can make a circle with radius of R.
If you're in a slip, it's like you're skidding out of that circle, so you're making a new circle bigger than R.
skidding is a bad phrase, but it tend to make the most sense for the definition, keep reading and it'll be explained.
If you're in a skid, it's like you're going down a waterslide and after a quick turn, you're falling into the turn, so you're making a new circle smaller than R.
The rudder is a flight control and can affect how you're applying your inertia. When everything is in balance, you have lower drag, the longitudinal axis is closely aligned with your flightpath. There is little air hitting the fuselage, and most of it steaming by it.
If you're in a slip, you're pointing the nose out of the turn, giving yourself more drag, and some thrust is helping you come "outside" of your turn.
On the turn coordinator, the ball comes inside of the turn, which means you need to step on the ball to bring it back in.
If you're in a skid, you're pointing the nose into the turn, giving yourself more drag, and some thrust is helping you come "inside" of your turn.
On the turn coordinator, the ball comes outside of the turn, which means you need to step on the ball to bring it back in.
To help a little more, think of yourself as wanting to make a perfect turn, your goal is that magic radius of R, with everything coordinated. Now imagine you're in a canyon, so you REALLY need to make this circle perfect. If you "slip" up, you're going to be going "outside" of your turn and be in serious trouble. If you want to stop it, you start to "skid" to a halt and as the speed comes down you make a smaller circle. People have to have better analogies, but I've been out of the seat for a year and I'm writing this quick.
When applied to landings, you can cross control. This means that you'll be using the rudder to yaw one way, and the ailerons to roll another. While not necessarily in balance, once you have some bank opposite of your yaw force you can make the airplane slip into a landing, making the fuselage basically one big spoiler to increase drag.
If you're cross controlled, slip.
If you're overly coordinated, skid.
If you're coordinated, well, you're coordinated.
http://www.faa.gov/library/manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-2of7.pdf page 3-9
http://www.faa.gov/library/manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-4of7.pdf page 8-10
Let me know if this helps, I might be able to rewrite this, it's just quick.
If you're in a slip, it's like you're skidding out of that circle, so you're making a new circle bigger than R.
skidding is a bad phrase, but it tend to make the most sense for the definition, keep reading and it'll be explained.
If you're in a skid, it's like you're going down a waterslide and after a quick turn, you're falling into the turn, so you're making a new circle smaller than R.
The rudder is a flight control and can affect how you're applying your inertia. When everything is in balance, you have lower drag, the longitudinal axis is closely aligned with your flightpath. There is little air hitting the fuselage, and most of it steaming by it.
If you're in a slip, you're pointing the nose out of the turn, giving yourself more drag, and some thrust is helping you come "outside" of your turn.
On the turn coordinator, the ball comes inside of the turn, which means you need to step on the ball to bring it back in.
If you're in a skid, you're pointing the nose into the turn, giving yourself more drag, and some thrust is helping you come "inside" of your turn.
On the turn coordinator, the ball comes outside of the turn, which means you need to step on the ball to bring it back in.
To help a little more, think of yourself as wanting to make a perfect turn, your goal is that magic radius of R, with everything coordinated. Now imagine you're in a canyon, so you REALLY need to make this circle perfect. If you "slip" up, you're going to be going "outside" of your turn and be in serious trouble. If you want to stop it, you start to "skid" to a halt and as the speed comes down you make a smaller circle. People have to have better analogies, but I've been out of the seat for a year and I'm writing this quick.
When applied to landings, you can cross control. This means that you'll be using the rudder to yaw one way, and the ailerons to roll another. While not necessarily in balance, once you have some bank opposite of your yaw force you can make the airplane slip into a landing, making the fuselage basically one big spoiler to increase drag.
If you're cross controlled, slip.
If you're overly coordinated, skid.
If you're coordinated, well, you're coordinated.
http://www.faa.gov/library/manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-2of7.pdf page 3-9
http://www.faa.gov/library/manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-4of7.pdf page 8-10
Let me know if this helps, I might be able to rewrite this, it's just quick.
Hammertime
Well-Known Member
To expand on Matt's analogy above. I always think of it as driving around the banked turns in a NASCAR track. If you go around the corner too fast and skid, centrifugal force wins (or lack of centripetal for the nerds out there) and the car (and in our case, the ball) slides uphill. If you go too slow, gravity wins, and you slip down the bank towards the bottom of the corner.
ProudPilot
Aeronautics Geek
By the way, I also thought that slip and skid terms should be reversed. Regrettably slip and skid are more accurately describing the ball on the turn coordinator than the actual condition. There are some things about aviation...
nosehair
Well-Known Member
I think of the terms as in a car.
when in a car, going around a flat curve too fast, your car starts skidding out because the road is too flat.
If you bank that curve, then the car stays on the road.
If you bank that curve too much, then the car will start slipping down towards the inside of the turn.
Not enough bank - skid
Too much bank - slip
when in a car, going around a flat curve too fast, your car starts skidding out because the road is too flat.
If you bank that curve, then the car stays on the road.
If you bank that curve too much, then the car will start slipping down towards the inside of the turn.
Not enough bank - skid
Too much bank - slip
ProudPilot
Aeronautics Geek
Yeah, that's reversed from how the AFH states it. Too much bank (or too much rudder into the turn) is a skid, and too little rudder is a slip.
