29 replies to this topic

[KVNY]

Quick question, whats the difference between a crab and a slip.  We've been having cross winds lately and my instructor was grilling me about how I was sliping when I should've been crabing.  For some reason i didn't think to ask him what the difference is     .  Help please?  

Edited by KVNY, 05 April 2005 - 11:03 PM.

[C172pilot]

if I recall correctly(lol)...

CRAB: you use aerlieron/ rudder corrections to adjust your position in relation to the wind.

AKA-cross wind landings and,if you're like me, constantly crab so you don't approach sideways. you are CRABBING.

SLIP: These are used for numerous purposes. but due to it being late and me tired. a SLIP is simply a technique used to rapidly loose alot of altitude without alot of foward movement NOR alot of speed gained(if done correctly).

SLIP is done by putting full rudder one direction(normally against wind**) and then aileron to the other side(SOMETIMES full aileron! But not for long.

by putting the aircraft facing against the wind and having aierlon control in heading you wish to follow(if that makes sense). It allows for all the air to hit the side of your aircraft and fly down the fueslage/emmpennage. Thus- creating HIGH level of drag, increasing decent rate for said time/distance.

The best way to visualize this is to picture yourself on final
EX-CRAB:
Winds are comming strongly from your west(left) side. So, you put left rudder and aileron to compensate for heading->keeping centered on runway. Then you SLOWLY take out the correction, only keeping in necessary rudder and minimal aileron when passing threshold.

EX: SLIP. same winds. put full right rudder, left aileron for heading correction.

Unless I'm completely brain dead. Those 'notes'. Work like a charm. I've never had a problem with them.

and DO NOTE: when landing in a cross wind, you WANT to land with your upwind(wind on aircraft side) first. WHY? to prevent any gust casuing a sudden and uncontrolable tip-over


EDIT: I may have the direction of winds for the examples on Crab/slip backwards. I really can't think straight. work was extremely tirering!!!! I'll fix it in the morning if it needs it

Edited by C172pilot, 05 April 2005 - 11:13 PM.

[KVNY]

ok thanks for trying.  

[vusaf_tbird1]

The better way to think of it, is the way a crab walks. You're angle to the runway is your crab angle from the direction of the wind.  See the cheap illustration below. A slip is facing the runway, using aileron and rudder to maintain a straight course to the runway. Your bank angle is roughly 20% (depending on the A/C) and your rudder deflection is opposite to control the angle to the runway. This allows you to maintain runway heading while losing altitude, instead of diving to the runway.
Wind  --->
                      ||
                      ||
                      ||    Runway
                      ||


                      \      Crab Angle

Hope this helps.

Edited by flight_guy00, 06 April 2005 - 07:33 AM.

[MeltedPixel]

Lets see if I can help here. Its a rather simple concept.

Crabbing means that you angle yourself into the wind and keep your wings level to correct for drift on final. Thats it, nothing else is done.

A "slip" in a crosswind landing refers to banking slightly into the wind and using opposite rudder to keep your nose on the center line. The bank will add a side component of lift in the direction the wind is coming from, thus stopping the drift caused by the crosswind. The rudder will simply keep you from actually turning into the wind.

However, when doing a crap you must at some point transition to a slip so you don't land with a side loading and fly off the runway on roll out. This is usually done right before the flare.

This being said, as you land in a slip, the up wind wheel WILL touch down first. You don't level your wings off, you keep that same degree of bank and that you had before until you feel the first wheel touch down.

The hardest thing about a crosswind landing is the approach, if you don't nail it simply go around. Its very rare to get a good landing out of an ugly approach.

Hope this helps!

Edited by MeltedPixel, 06 April 2005 - 09:31 AM.

[jayca1]

I agree with Meltedpixel on this one.

As I have said in one of my previous posts on here (see link attached), approach to landing is done by crabbing ... This is balanced flight. Flying in a straight line with nose pointed into the wind sufficiently to maintain your track (remember heading and track ?).

A slip is using a combination of rudder and opposite aileron to maintain your track. Not a good idea to use slip for long on an approach. Use it for landing.

http://www.fs2004.co...=0

Jay

[C172pilot]

and for that. I won't be a teacher.. I suck HORRIBLY at explaining things lol.

[MeltedPixel]

C172pilot, on Apr 6 2005, 02:57 PM, said:

and for that. I won't be a teacher.. I suck HORRIBLY at explaining things lol.

You had me confused after the third sentance

[Woodsie11]

MeltedPixel, on Apr 6 2005, 09:30 AM, said:

However, when doing a crap

LOL I laughed at that !!!!

Simple typing error

[MeltedPixel]

Woodsie11, on Apr 6 2005, 04:03 PM, said:

MeltedPixel, on Apr 6 2005, 09:30 AM, said:

However, when doing a crap

LOL I laughed at that !!!!

Simple typing error

ROFL!
I didn't notice that, hahahahah

[KVNY]

MeltedPixel, on Apr 6 2005, 06:30 AM, said:

Crabbing means that you angle yourself into the wind and keep your wings level to correct for drift on final. Thats it, nothing else is done.

A "slip" in a crosswind landing refers to banking slightly into the wind and using opposite rudder to keep your nose on the center line. The bank will add a side component of lift in the direction the wind is coming from, thus stopping the drift caused by the crosswind. The rudder will simply keep you from actually turning into the wind.

Ah ok.  That straightens it all out right there.  Between you guys and my books this all makes perfect sence to me now     . As for touching one wheel down first and going around if it doesnt work out... thats kinda difficult in a glider... with only one wheel    

Quote

However, when doing a crap

Wahahahaha    

Anyways, thanks too all

Happy slipping, crapping, and crabbing.

Edited by KVNY, 06 April 2005 - 06:24 PM.

[MeltedPixel]

Quote

Happy slipping, crapping, and crabbing

Classic!

[C172pilot]

LOL! great!!!!

I stilll don't understand how I can understand it in person while flying, but can't explain much of anything to ANYONE, unless I'm in person with them. LOL OH WELL

[KVNY]

C172pilot, on Apr 6 2005, 04:11 PM, said:

LOL! great!!!!

I stilll don't understand how I can understand it in person while flying, but can't explain much of anything to ANYONE, unless I'm in person with them. LOL OH WELL

lol. Its one of those things that really needs hand gestures and scribbles on a peice of paper i guess.

[citationpilot]

vusaf_tbird1, on Apr 6 2005, 07:32 AM, said:

A slip is facing the runway, using aileron and rudder to maintain a straight course to the runway. Your bank angle is roughly 20% (depending on the A/C) and your rudder deflection is opposite to control the angle to the runway. This allows you to maintain runway heading while losing altitude, instead of diving to the runway.
Wind  --->
                      ||
                      ||
                      ||    Runway
                      ||


                      \      Crab Angle

Hope this helps.

How would you slip in a T-38, for example?  Does it handle winds well?

[WillMcCaskill]

citationpilot, on Apr 7 2005, 07:22 PM, said:

vusaf_tbird1, on Apr 6 2005, 07:32 AM, said:

A slip is facing the runway, using aileron and rudder to maintain a straight course to the runway. Your bank angle is roughly 20% (depending on the A/C) and your rudder deflection is opposite to control the angle to the runway. This allows you to maintain runway heading while losing altitude, instead of diving to the runway.
Wind  --->
                      ||
                      ||
                      ||    Runway
                      ||


                      \      Crab Angle

Hope this helps.

How would you slip in a T-38, for example?  Does it handle winds well?

Citation just give it up!   You have to be kidding me, your display of maturity ( or lack of it )  the past few days is the most pathetic thing i have ever witnessed.

Edited by WillMcCaskill, 07 April 2005 - 07:30 PM.

[citationpilot]

My interest in genuine. You want me to believe he's a fighter pilot so I'm going to treat him like the experienced aviator he is and ask him how the awesome airplanes he flew fly. There shouldn't be any problem in asking him simple questions like this, right?

[WillMcCaskill]

citationpilot, on Apr 7 2005, 08:38 PM, said:

My interest in genuine. You want me to believe he's a fighter pilot so I'm going to treat him like the experienced aviator he is and ask him how the awesome airplanes he flew fly. There shouldn't be any problem in asking him simple questions like this, right?

Oh stop kidding yourself. You, I, and the rest of the forum know your question is with bad intentions. You aren't curious about how it handles, according to you he isn't even a fighter pilot.

[axvx8xoxr]

citationpilot, on Apr 7 2005, 08:38 PM, said:

My interest in genuine. You want me to believe he's a fighter pilot so I'm going to treat him like the experienced aviator he is and ask him how the awesome airplanes he flew fly. There shouldn't be any problem in asking him simple questions like this, right?

You would slip a T-38 as you would any other aircraft.  "How it handles them" could be found easily on the internet, and would prove nothing about his experience.

What's with people out to get each other lately?

If I tell you guys I drive an F250 someone will probably start questioning it.  

[C172pilot]

you're questions are about as legitimate as me saying I marshalled a United 777 at DuPage airport and then was given a million bucks..

seem bogus. his pics obviously have proof of his experience. Obviously, as he's in the military(or a branch of) he blocked out himself to prevent anyone from seeing his entire face/division. Heck, I still do the same thing from having lived overseas as part of the USAF... That is, telling where I exactly live nowadays(what town)