slip to a landing

[little pat]

Is it better slip in and then pull a notch of flaps, or is it ok to slip in with one notch of flaps.

I noticed the other day... as I sliped in with one notch of flaps ( PA-18 ) that I had exceeded 80mph (~83mph). I never have done that with flaps extended. I quickly straightened up, pulled up and lost the speed then overshot/aborted the landing and went around.

 

[Seaworthy]

My PA-12 comes down like a coke machine with two notches of flap and a slip. I slip then pull in flap.

 

[Longwinglover]

little pat,

No offense, but go and practice your slips.

You are lowering your nose in the slip and that is why you are gaining airspeed. This works the same whether you are flying coordinated (straight) or un-coordinated (slip) -- lower the nose and you will pick up speed, raise the nose and you will loose speed.

John Scott

 

[SteveE]

Why dont you just come in with flaps on and then slip if you see you are too high? Just keep the nose either up or down for your airspeed.

 

[redrooster]

Instead of slipping, I like pulling the nose up for lower airspeed/higher sink rate. Works real well for me. But it is counter-intuitive. Kinda reminds me of "to go up,pull, and to go down, pull harder".

Rooster

 

[mvivion]

Forward slips, properly performed, work fine with half or full flaps in a Cub.

Redrooster, I would guess you have VG's--correct? The VG's make that sort of descent functional. May be a little on edge without them, though.

MTV

 

[SteveE]

Mike, The plackard on say a 172 says no slips with flaps. I remember my instructor just about crapped when I was too high and I just slipped it (the 172) he got onto me. But what happens, do you loose the air over the horizontals? and then stall?

 

[jpentick]

Is it wise to slip with flaps when on floats in a PA-12?

 

[mvivion]

Steve,

I thought he was discussing a Super Cub, not a Cessna.

Cessna had two different admonitions regarding slips with flaps deployed. Some Cessnas have the admonition "Slips with flaps deployed are not recommended" (or words to that effect), and a few have a warning that "Slips with flaps are prohibited".

A Cessna 206 slips like a bandit with full flaps.

A 172 does as well. Depending on what year it is, you may see different recommendations for the same model aircraft. I think most of this is liability driven. Take a look at the POH for the particular airplane and go from there. If it says not recommended, they are approved. If it says prohibited, they're not.

The theory is that flaps may blanket the horizontal tail, causing a tail stall. That may be possible in some Cessnas, but I think you'd have to work pretty hard at it. The 206 has huge flaps, and the older ones went to a full 40 degrees. Slips work fine in them.

They also work fine in my 170, and are not prohibited or recommended against in it.

MTV

 

[mvivion]

jpentik,

Why not perform slips in a 12 on floats? If the plane hasn't been modified with flaps, that's the only way you can perform a steep descent to a landing.

Piper knew that.

There is nothing scary or dangerous about slips. Read Rich Stowell's books on stall/spin awareness. A slip, by definition, involves roll opposite to yaw. A spin, by definition, involves a roll and yaw in the same direction.

Now, a skid------is a yaw and a roll the same direction. THAT is a bad thing.

Don't be afraid of forward slips. Get with a good instructor, practice them, practice managing your airspeed in them, and use them.

Great tools to keep in your tool box.

MTV

 

[SteveE]

Mike, I knew he was asking about Supercubs, but I knew you would be looking again and I could get my answer. I could care less about Cessnas, I just wanted to know, and your opinion matters. It is helping me get my private strip. Thanks

 

[Alex Clark]

While I have slipped PA-18s with flaps extended, for some reason my first instructor years ago told me not to do so. It did feel a bit odd with full flaps and droop tips...

My PA-11 on floats slips rather well.

I also perform the old biplane tail-wag if I am 5-10 feet too high coming over the shoreline trees...

 

[180Marty]

Alex wrote

old biplane tail-wag

What's that Alex?
Marty

 

[scubber]

I have been hesitant to join in, but... at 80+ miles an hour a cub is not going to come down . .even in full control- travel slips, flaps/no flaps. In fact your going to get hurt in short places. I am not a a "bush pilot", nor have the hours that many on this site have. But, haveing learned to fly out of a 800' farm stirp with power lines off the one end & woods on the other end, & and 90 hp PA-18 (no flaps) you learn to slip. If your going to come down . . .with a high lift wing . ."slow down"., just as other posts have indicated. You can land shorter w/ flaps than without, but I have landed shorter w/out flaps than some PA-18's with flaps, that are coming in too fast. And I don't "hand it on the prop". I would suggest getting some practice at some slower speeds. My cub still does not have flaps, but now has more "ponies" 135. But at 55 . . (or slower) comes down rather nice in "full travel" slips". I can only imagine that flaps can only make it better.
Have been flying the same cub since 1964 and have owned it since 1976, and still must admit I have never flown a Super Cub w/ flaps. So . . maybe take my opiniion with a grain of salt. Larry C.

 

[nesincg]

What are flaps?

 

[bob turner]

Grain of salt taken. My Cub comes down almost vertically at 80 with full rudder. I start it at about 42 indicated, then feed in forward stick to go down. Rollout is when I am slow enough to flare and land, which means I start slowing up before I get to the touchdown zone. Drag is proportional to velocity squared, and a slip is just drag.

The Super Cub doesn't seem to slip as well as the J-3, but does fine at full flaps. Full flaps and floats - I think I would not delay the rollout too much, because it seems to want to continue the descent.

I have had a couple of Super Cubs fall off on one wing just before touchdown - a non-event, of course, because touchdown stops the roll immediately. Still, it says there are times, even in ground effect, when the thing will quit flying suddenly. All were cross-control. Never had that experience in a J-3.

 

[Ursa Major]

Steve,

IA 172 does as well. Depending on what year it is, you may see different recommendations for the same model aircraft. I think most of this is liability driven. Take a look at the POH for the particular airplane and go from there. If it says not recommended, they are approved. If it says prohibited, they're not.

The theory is that flaps may blanket the horizontal tail, causing a tail stall. That may be possible in some Cessnas, but I think you'd have to work pretty hard at it. The 206 has huge flaps, and the older ones went to a full 40 degrees. Slips work fine in them.

They also work fine in my 170, and are not prohibited or recommended against in it.

MTV

A number of years ago I was chasing the needles on a practice ILS approach in a 172 at about 400' AGL. I was higher than I should have been and a little too fast. Okay, says I, I'll just kick in a little rudder and slip her on down. I had probably half flaps and I had just pushed the rudder pedal when I thought the tail had come off. It was a pretty violent shudder and I lost all interest in slipping (or continuing the approach at that point). I became a believer in the placard prohibiting slips after that.

I had slipped other cessnas with flaps extended without a problem, but that one bit back.

 

[Chris L]

So, say I go to a safe altitude and slip very aggressively, with full flaps, until something happens. What would the something be? A stall, spin, shudder, ??? Or, would I just run out of controls to cross up? Assuming airspeeds in the final approach range, but not lower.

 

[mvivion]

Worst case scenario:

AIrplane stalls, and spins. Now you are in a spin and Cessna very specifically noted for all its airplanes that were approved for spins that
"Spins with flaps deployed are prohibited".

I'd mind that one, but again, I think you'd have to work at it pretty hard to get there.

If there is a placard in the airplane or an admonition in the AFM that says DON'T slip the airplane--DON'T!

That, gentlemen, should not be rocket science :-? .

MTV

 

[behindpropellers]

You can drop some serious altitude with our straight tail 172 and full flaps. To the point where it is not fun.

Personally, if you have flaps getting a stabilized approach set up in the first thing is key.

 

[bob turner]

But slips are so much fun!

 

[Widebody]

little pat,

Listen to scubber he's got your answer. Flaps or no flaps, try both, a Cub handles both just fine. What books tell you may not always be true, but an airplane will never lie to you, if it don't like what you're doing you'll know it and you better quit or it will bite you, this applies to all planes. Have fun

Brad

 

[little pat]

By the way...the do not exceed speed for flaps in the PA-18 is 80mph. I was more worried about tearing a flap off. anyone seen that before?

 

[cubflier]

Little Pat

The flap extension speed is there for a reason but I would image most of us have exceeded that at some point. Things will loosen or bend before they just rip off unless you go to some wild extreme.

With regards to your original question, I rarely slip on approach. The flaps on your cub do a wonderful job and with the right pitch and power combination, using your flaps, you should be able to control your decent without the need for a slip.

But - slips are a very handy tool and you should learn them. Go up to a safe recovery altitude and learn them.

As for needing and instructor to practice slips, if you feel you need one then take one along. But there is a point where they are just baggage that pulls on your stick and pushes on your rudder just at about the same time you were about to figure things out on your own. I've considered wiring a switchable spark plug lead to my back seat cushion and rear stick that I could energize when I felt I had an over eager instructor.

Good Luck - Jerry

 

[mvivion]

Jerry,

Good point. On the other hand, if his forward slips turn into exceeding flap speeds, maybe a good instructor could assist.

Emphasis on the term GOOD here, since I fully agree. One of my pet peeves is instructors from across the river here who never let their students talk on the radio. Instructor always gets to the mic key first.

I think your spark plug idea is a good one.

MTV

 

[Jerry Gaston]

Slips and flaps??? I can't imagine needing both either slip to a landing or use flaps (if you got them) but why does anyone need both?
As far as slipping a cessna especially a 185 while having flaps down is asking for it (plain and simple)

 

[mvivion]

Jerry,

Slips AND flaps?? Why? Why not?? If you have a really steep descent into a landing, it works. If nothing else, it is all part of becoming the master of your airplane.

And, 185's also slip fine with flaps deployed.

Note that the 1985 Cessna 185 POH does not contain any suggestion that slips with flaps extended should be avoided, EXCEPT in the skiplane supplement, where you'll find an admonition that slips with flaps extended should be avoided. Even that doesn't say they are prohibited.

Here's a question for you Cessna guys: If you don't perform slips with flaps extended, does this mean you NEVER use flaps while landing or taking off in a crosswind?? The specific maneuver which allows one to align with the runway in a crosswind is ------- SLIP

I'm with Widebody to a point. Unless the book absolutely says DO NOT slip with flaps extended, why not?

MTV

 

[Jerry Gaston]

MTV If the cross wind is sever I never use flaps only a slip or a crab can't seem to get the thing on the ground if flaps are down.

 

[cubflier]

Slips and flaps??? I can't imagine needing both either slip to a landing or use flaps (if you got them) but why does anyone need both?

Jerry,

It's rare that I do full flap slips but I have one place that I go to up the Knik River that involved descending into a very small strip tucked up against a rock bluff. I full flap slip down the face of the bluff to burn altitude while maintaining my visual references. It's the only way I can get in there with comfort. I have a friend that just sets up a high descent mush over this rock face and lands quite gracefully.

He thinks the slip is uncomfortable and I think the mush in is uncomfortable. He also sits higher up in his cub than me which may contribute to the different style.

Take Care - Jerry