Forward slip vs flaps

[FastEddieB]

Skid: Too much rate of turn for the angle of bank.

 

Or, put another way, too little bank for the rate of turn.

 

In any case, ball goes to the outside, and in a stall the inside wing will stall first.

 

 

Slip: Too much bank for the rate of turn (which may be zero)

 

Or, put another way, too little rate of turn for the amount of bank.

 

In any case, ball goes to the inside, and in a stall the outside wing will stall first.

[FredG]

Eddie, thanks. My first comment was made with the understaning of skid and slip as you defined them. Does the outside wing stall first in a slip because airflow over it is partially blocked by the fuselage?

[sandpiper]

John, thanks. Which wing is the outside wing in a slip? I'm having trouble visualizing that.

 

Lets say you are turning left, 30 degree bank. In this case the outside wing is always the one on the right, slipping or skidding.

 

If turn is coordinated, there should be no tendency to go left or right. If slipping you should roll to the outside of the turn which, in this case, is to the right. Skidding will roll you to the inside, or left.

 

Get an instructor, go practice. See what your plane does.

[FastEddieB]

An analogy I've used.

 

Imagine you're at the track at Daytona. The high bank has been designed for a car going 150 mph (let's say).

 

You're in a souped up Edsel. It has fuzzy dice hanging from the mirror.

 

Take the high bank at 150 mph and the dice hang straight down - your rate of turn is appropriate for the bank.

 

Take the high bank at 100 mph and the dice will drop towards the inside of the track - your rate of turn is too little for the bank. This is equivalent to a slip.

 

Take the high bank at 200 mph and the dice will swing towards the outside of the track - your rate of turn is too great for the bank. This is equivalent to a skid.

 

Does that help, or just confuse things?

 

Note what the ball does when you make a turn taxiing on level ground. Would that be the indication of a slip or a skid, and why?

[FastEddieB]

Eddie, thanks. My first comment was made with the understaning of skid and slip as you defined them. Does the outside wing stall first in a slip because airflow over it is partially blocked by the fuselage?

 

You're welcome.

 

Yes, that is my understanding.

[FredG]

John, and Eddie, thanks for your input. I am aware of the definition of slip and skid, and I know what the "ball" indicates. My plane has both a Dynon and a mechanical ball (the kind filled with kerosene). I have slipped my plane hundred of times while landing, in order to loose altitude without gaining airspeed. I know what coordinated means, as well.

 

Eddie, your example is similar to an illustration in the airplane flying handbook showing a woman pilot with a ponytail that acts like your dice in a slip, coordinated flight, and a skid.

 

John, when I asked about the outside wing, I was not thinking of a slipping turn, rather a slip of the kind that was being discussed earlier in the thread, ie., one made on a constant heading. Your advice to get an instructor is good advice. I am surprised that it is not given more often when pilots on this forum ask for guidance with problems they are having landing, flying, etc.

 

FWIW, when I mentioned above that I saw an aerodynamic difference between a slip and a skid, I was not seeking a a basic understanding of these two flight conditions. Rather I was hoping to have discussion about a concept that I have not heard about elsewhere, ie., that the speed of air over the wings would differ in a skid whereas it would not differ in a slip. Nor does it differ in a coordinated flight. Is this correct?

 

I was exploring differences in these flight conditions that might be consistent with Charlie Tango's observation that stalls in a skid are more aggressive than stalls in a slip.

 

Thanks.

[Runtoeat]

I've wondered, since our CT's present such an aerodynamic shape in not only the frontal direction but also in the profile direction, if slipping them results in the "normal" drag one finds when slipping the Piper/Cessna type airplane? In particular, when performing the forward slip on a CT, is the drag produced from doing this equal to the drag produced by our large and prominent flaps (40 degree in CTSW with assistance from the added drop of ailerons)? Just wondering if anyone has compared slipping with just full flaps. My thought is that doing just full flaps provides me with the altitude loss I need to correct for a "too high" approach setup without using a slip. Certainly, I also use forward slip with full flaps to really get into a tight spot but for the normal short field seems like full flaps is sufficient.

[FlyingMonkey]

I've wondered, since our CT's present such an aerodynamic shape in not only the frontal direction but also in the profile direction, if slipping them results in the "normal" drag one finds when slipping the Piper/Cessna type airplane? In particular, when performing the forward slip on a CT, is the drag produced from doing this equal to the drag produced by our large and prominent flaps (40 degree in CTSW with assistance from the added drop of ailerons)? Just wondering if anyone has compared slipping with just full flaps. My thought is that doing just full flaps provides me with the altitude loss I need to correct for a "too high" approach setup without using a slip. Certainly, I also use forward slip with full flaps to really get into a tight spot but for the normal short field seems like full flaps is sufficient.

 

My experience says the CT is a very good airplane in a slip. It gets plenty of sink in that configuration. While the fuselage is skinny, the tail surfaces are large, and that probably contributes to its good "slipability".

[Dan Kent]

An analogy I've used.

 

Imagine you're at the track at Daytona. The high bank has been designed for a car going 150 mph (let's say).

 

You're in a souped up Edsel. It has fuzzy dice hanging from the mirror.

 

Take the high bank at 150 mph and the dice hang straight down - your rate of turn is appropriate for the bank.

 

Note what the ball does when you make a turn taxiing on level ground. Would that be the indication of a slip or a skid, and why?

 

Hey Eddie,

Can I split some hairs? When you say straight down did you really mean perpendicular to the floor boards, since the bank angle will tilt the Edsel. (In this example straight down would be toward the center of the earth).

 

I think the level ground turn would be a skid, because there is no bank angle, thus your rate of turn would be greater than your bank angle (zero in this instance).

[FastEddieB]

Hey Eddie,

Can I split some hairs? When you say straight down did you really mean perpendicular to the floor boards, since the bank angle will tilt the Edsel. (In this example straight down would be toward the center of the earth).

 

I meant straight down in reference to the Edsel

 

I think the level ground turn would be a skid, because there is no bank angle, thus your rate of turn would be greater than your bank angle (zero in this instance).

 

Exactly right.

[Dan Kent]

I meant straight down in reference to the Edsel

 

I was envisioning Talladega .

[FastEddieB]

When you say straight down did you really mean perpendicular to the floor boards, since the bank angle will tilt the Edsel.

 

Thinking about it, at 150 mph the bank angle should just compress the springs, and not tilt the Edsel at all.

 

Right?

[Ed Cesnalis]

This flying car is a leaner (2min on video), it banks whether the track does or not.

 

[Doug G.]

Eddie, I think we may have some NASCAR challenged folks here.

Daytona and Talledega both are high banked oval tracks, so when the properly set up Edsel is at the appropriate speed it will not try to slide up the track or down, the force of the bank will be perpendicular to the track and the Edsel. It will push the driver straight down in the seat. The car won't lean because of the counter balancing forces. (This will not necessarily be the fastest speed around the corner since in a race care it will depend on frictional force which in turn is determined by suspension - but the analogy does not go that far.)

[Dan Kent]

 

 

Thinking about it, at 150 mph the bank angle should just compress the springs, and not tilt the Edsel at all.

 

Right?

I think there will be no side force only when the horizontal conponent of the force due to gravity (30 degrees at max bank) equals the centrifugal force. @ 200+ mph I think the centrifugal force is considerably more. That's why the cars drift out at high speed as the bank angle decline.

[Doug G.]

Technically there is no centrifugal force. The centripital force applied by the bank counteracts the force trying to keep the car going straight - ala Newton. The real miracle here is the Edsel going 200 mph! lol

[Jim Meade]

Did a full slip with 40° flaps and idle thrust today and once when I glanced at the VSI it was 1050.

[Roger Fane]

Did a full slip with 40° flaps and idle thrust today and once when I glanced at the VSI it was 1050.

That is gentle. I've done slips in my former CTSW with the Dynon showing 2,300 - 2,400 foot per minute descents. I believe it was dropping faster than that as it didn't seem like I held it for 3+ minutes loosing 7,000 + feet in altitude. The CHT and Oil Temps sure cooled off quickly.

[coppercity]

It's easy to get over the 62kt Vfe for 30,35,40 flaps with steep slips and full flaps, just keep an eye on it as the CT likes to pitch down pretty good with a full rudder slip and full flaps.

[FlyingMonkey]

It's easy to get over the 62kt Vfe for 30,35,40 flaps with steep slips and full flaps, just keep an eye on it as the CT likes to pitch down pretty good with a full rudder slip and full flaps.

 

Hard to know when that's happening since airspeed indications become suspect in an aggressive slip...

[coppercity]

Check your ground speed before you enter and while your slipping they should stay about the same.

[Ed Cesnalis]

http://www.youtube.com/watch?v=xwrfEsCiltc&feature=youtu.be

[WmInce]

Thanks CT . . . that was great!

[FlyingMonkey]

Pure gold CT...thank you.