Airspeed when Slipping to landing

poadeleted21

poadeleted21

Touchdown! Greaser!
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If you're side slipping to a landing in a stiff crosswind, what IAS do you use? Higher, Lower, Same or "don't look at it"
 
Definitely not "don't look at it". Airspeed will bleed off quickly when you're in a slip, so keep that nose down and keep scanning the IAS

My instructor had me use the normal speeds for any reasonable crosswinds.. if its really blowing hard or gusty he told me to lose one notch of flaps and increase speed 5 kts or so.
 
in a Xwind the same unless I need extra for more rudder autority.

Now a FWD slip I target a slower speed to raise the sink rate.
 
bartmc said:
If you're side slipping to a landing in a stiff crosswind, what IAS do you use? Higher, Lower, Same or "don't look at it"
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Slipping or crabbed? Stiff crosswind, and either way I'm going to come in a bit hotter, with less flaps.
 
Can your ASI be believed when side slipping? I'm referring to IAS.
 
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Mine seems to be about right, as does the blade style on the Diamond I trained in.
 
The blade style pitot - static should be less affected by the slip than the type that has the static port mounted on the side of the fuselage.
 
Here's a shock: it depends.

:rolleyes:

I usually slip continuously base to final in the Chief because it's fun, it provides the best view of the runway environment, it bleeds off ALOT of altitude in a short time, and it's fun.

I usually slow to 60 MPH abeam the numbers, then commence the slip. After that I don't care much about airspeed -- if it increases, I'm also increasing drag.
 
dell30rb said:
The blade style pitot - static should be less affected by the slip than the type that has the static port mounted on the side of the fuselage.
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It's a good point on the static port, I don't remember slips in single port 172s but my 182 has one on each side of the fuselage. I'd suspect that the pressures probably average out to be close to correct.
 
I don't look at it. Pay attention to the pitch. Keep it at a nice healthy nose down angle and you'll be fine. Practice this at altitude and you can transition in and out of the slip to see where your airspeed went at different pitch angles.
 
bartmc said:
Can your ASI be believed when side slipping? I'm referring to IAS.
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Depends.

In a Cessna 120 in a right pedal to the floor slip I could drive the IAS pretty much to zero.

Many other aircraft would be less sensitive, but I would expect the IAS to usually read lower than actual due to the pitot tube being out of alignment in a hard slip.

On the bright side, when you are slipping hard, you can push pretty hard and not gain that much speed since you are flying sideways. Push is good.

Try it at altitude to see how your airplane behaves. You can also look at the delta air speed as you kick out to straight (again, best practiced at altitude).
 
bartmc said:
Can your ASI be believed when side slipping? I'm referring to IAS.
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The more yawed the plane, the less accurate the ASI. Best bet is to maintain pitch attitude and don't look at the ASI.

Also, your airplane and its pitot tube cannot tell the difference between a side slip and a forward slip, so the above advice is applicable to all slips, not just side slips.
 
There was a good article on AvWeb that put the lie to increased speed and less flaps, at least in a hershey bar wing. Normal approach speed, full flaps, gets that sucker on the ground in the shortest period of time and plant it. Retract flaps once firmly on the runway. Made sense to me, so that 's how I do it.
 
Chip Sylverne said:
There was a good article on AvWeb that put the lie to increased speed and less flaps, at least in a hershey bar wing. Normal approach speed, full flaps, gets that sucker on the ground in the shortest period of time and plant it. Retract flaps once firmly on the runway. Made sense to me, so that 's how I do it.
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Agree, but post that on the SP board and you'll need your flamesuit on. :)
 
Chip Sylverne said:
There was a good article on AvWeb that put the lie to increased speed and less flaps, at least in a hershey bar wing. Normal approach speed, full flaps, gets that sucker on the ground in the shortest period of time and plant it. Retract flaps once firmly on the runway. Made sense to me, so that 's how I do it.
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Hunh? I'm not sure how this applies to slips?

:dunno:
 
dmccormack said:
Hunh? I'm not sure how this applies to slips?

:dunno:
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The article was obviously about x-wind landings...why else the mention of not increasing speed and not retracting flaps, then retracting on the ground. Slipping is implicit with x-wind landings.
 
dmccormack said:
Hunh? I'm not sure how this applies to slips?

:dunno:
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How do you get it aligned with the runway with a healthy crosswind?
I let it crab on final till I get a good sense of what the wind is doing to me, then kick it into a slip to straighten it out, full flaps normal approach speed, drop the upwind wing for touchdown.

There's only two reasons I can think of to use a slip. Way high on final, or crosswind landings.
 
Chip Sylverne said:
How do you get it aligned with the runway with a healthy crosswind?
I let it crab on final till I get a good sense of what the wind is doing to me, then kick it into a slip to straighten it out, full flaps normal approach speed, drop the upwind wing for touchdown.

There's only two reasons I can think of to use a slip. Way high on final, or crosswind landings.
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I'll give you 2 more;

Scaring Passengers

In an emergency - in flight fire or oil on the windscreen
 
We're on page 17 over at the piper forum arguing about if there is an aerodynamic difference in forward vs side slips (No!) but it got me to thinking, I usually just setup my 75MPH final speed in a crosswind but really don't even bother looking at the ASI when doing a forward slip so I was wondering if that was dangerous.
 
Chip Sylverne said:
There's only two reasons I can think of to use a slip. Way high on final, or crosswind landings.
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I can think of two more - visibility on final and fun. The former mostly applies to biplane pilots. And the latter...well it goes without saying that biplane pilots are already having fun. :D

Too bad many folks think of a slip (to lose altitude) as error correction. How about thinking of a slip as just another pilot trick to consistently put the airplane where you want without having to rely on power? When used properly, slips can be a sign of GOOD planning, not bad planning.

Palmpilot said:
What's the SP board?
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studentpilot
 
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bartmc said:
We're on page 17 over at the piper forum arguing about if there is an aerodynamic difference in forward vs side slips (No!) but it got me to thinking, I usually just setup my 75MPH final speed in a crosswind but really don't even bother looking at the ASI when doing a forward slip so I was wondering if that was dangerous.
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Unless the crosswind component is something on the order of 30 knots or more, you're not going to be yawed enough to significantly affect ASI readings in a crosswind-correcting slip. It's only when you use a full-rudder altitude-losing slip that you're yawed enough for it really to matter. Either way, if you start the slip while at proper final approach speed, and don't let the nose go up or down as you do, you'll be just fine.
 
RoscoeT said:
I can think of two more - visibility and fun. The former mostly applies to biplane pilots. :)

Too bad many folks think of a slip (to lose altitude) as error correction. How about thinking of a slip as just another pilot trick to consistently put the airplane where you want without having to rely on power? When used properly, slips can be a sign of GOOD planning, not bad planning.



studentpilot
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I was going to say oil covered windshield, but I like yours better. Good point well taken!
 
RoscoeT said:
The article was obviously about x-wind landings...why else the mention of not increasing speed and not retracting flaps, then retracting on the ground. Slipping is implicit with x-wind landings.
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Not really. A crosswind can also be handled using the crab and kick method (It does work with very good timing) or the curve method.
 
Ron Levy said:
Unless the crosswind component is something on the order of 30 knots or more, you're not going to be yawed enough to significantly affect ASI readings in a crosswind-correcting slip. It's only when you use a full-rudder altitude-losing slip that you're yawed enough for it really to matter. Either way, if you start the slip while at proper final approach speed, and don't let the nose go up or down as you do, you'll be just fine.
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Makes sense, Gracias.
 
RoscoeT said:
Too bad many folks think of a slip (to lose altitude) as error correction. How about thinking of a slip as just another pilot trick to consistently put the airplane where you want without having to rely on power? When used properly, slips can be a sign of GOOD planning, not bad planning.
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Exactly right.

I use a slip to place the airplane exactly where I want it to be. The ability to slip well must be practiced frequently. Why not on final?
 
dell30rb said:
Unfamiliar with the curve method.. can you elaborate?
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It's one of those old-timer techniques...

You land on the downwind side of the runway and intentionally roll in a curve towards upwind. The centrifugal force helps you stay planted.

I'm not good enough to do it in a TW. I tried it in a BE35 and it worked, but made me wonder about side loads.
 
Chip Sylverne said:
I was going to say oil covered windshield, but I like yours better. Good point well taken!
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Some biplane pilots have permanently oil-covered windshields...they don't care too much. :D
 
dmccormack said:
It's one of those old-timer techniques...

You land on the downwind side of the runway and intentionally roll in a curve towards upwind. The centrifugal force helps you stay planted.

I'm not good enough to do it in a TW. I tried it in a BE35 and it worked, but made me wonder about side loads.
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Sorta like landing an ercoupe in a crosswind?
 
dell30rb said:
Sorta like landing an ercoupe in a crosswind?
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The Ercoupe's landing gear was designed to handle it. Not many other planes' gear are.

And that "curveball" method is not one you'll see me attempt. I'll stick with the good old-fashioned wing-low/rudder-pointed slip to touchdown with zero (or as close as I can get) crab and drift.
 
Ron Levy said:
Unless the crosswind component is something on the order of 30 knots or more, you're not going to be yawed enough to significantly affect ASI readings in a crosswind-correcting slip. It's only when you use a full-rudder altitude-losing slip that you're yawed enough for it really to matter...
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Aha, that explains why my instructor only mentioned it in regard to forward slips.
 
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Ron Levy said:
The Ercoupe's landing gear was designed to handle it. Not many other planes' gear are.

And that "curveball" method is not one you'll see me attempt. I'll stick with the good old-fashioned wing-low/rudder-pointed slip to touchdown with zero (or as close as I can get) crab and drift.
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I use the slip method and am a convert from the crab down final and kick method. I've heard low wing pilots like the crab over the wing low to reduce the chance of dragging a wing but I've landed in some stiff winds and it's not a concern I have anymore.
 
Skylane81E said:
It's a good point on the static port, I don't remember slips in single port 172s but my 182 has one on each side of the fuselage. I'd suspect that the pressures probably average out to be close to correct.
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That's the reason for the two ports: to get an average static pressure so that the airspeed reads relatively accurately. A 172 has one on the left side, and a slip to the left raises static pressure and drives the ASI down. A slip to the right doesn't make such a big difference.

Dan
 
bartmc said:
I use the slip method and am a convert from the crab down final and kick method. I've heard low wing pilots like the crab over the wing low to reduce the chance of dragging a wing but I've landed in some stiff winds and it's not a concern I have anymore.
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I don't much care whether the wings or on top or bottom -- landing in a crab eats tires, and tires ain't cheap. Either way, I'll crab down final until the point where I'm committing to land, then I'll kick out the crab and slip it to touchdown. Only planes I know which really can't handle the wing-low method (other than the 'Coupe) have castering landing gear so they can land in a crab without shredding the tires, and I'm not flying B-52's or C-5's.
 
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