Slipping Cessnas with full flaps.....

E_Dawg

Moderator
OK I realize this has been discussed; however today I found something that makes sense and pretty much seals the deal for me.

"Slips with flaps are either prohibited or not recommended in the POHs. The slip problem arises from the possibility of extended flaps under certain conditions such as in slips or wind shear blocking or interfering with the airflow over the horizontal tail surfaces. I have had such an occurrence in a C-150. The tail surfaces stall and the nose pitches straight down before the stall warner has a chance to yelp. Cessna merely admits that there may be control oscillations."

He does also mention that this only happened once in 9000hrs of flying. Prior to coming across this I was never opposed to slipping with full flaps; however I'm going to rethink that now!

http://www.whittsflying.com/Pagec2C-172.htm#anchor917446
 

ready2fly

Well-Known Member
HEEEEEY - my instructor demonstrated a slip with 20% flaps in a 150 a while back!!

YIKES! Our approach is over water.... shallow water. Shallow enough for what's left of the plane after hitting the water to be TOTALLY smashed against the bottom, and deep enough to completly submerge you in what's left of the plane should you somehow survive.

... so much for THAT maneuver.
 

pscraig

Well-Known Member
I've flown a few 172s that have some vicious pitch oscillations in turbulence when slipping with full flaps. Don't know how truly dangerous it was, but at 400AGL on final, not the kind of experience I am after.
 

EatSleepFly

Well-Known Member
Guess it depends on the year. I've slipped 172's plenty of times. Creates a little buffeting, but nothing too adverse.
 

sbav8r

New Member
[ QUOTE ]
HEEEEEY - my instructor demonstrated a slip with 20% flaps in a 150 a while back!!

YIKES! Our approach is over water.... shallow water. Shallow enough for what's left of the plane after hitting the water to be TOTALLY smashed against the bottom, and deep enough to completly submerge you in what's left of the plane should you somehow survive.


[/ QUOTE ]

And if you do get out then all the blood in the water would attract a feeding frenzy of sharks.
 

E_Dawg

Moderator
[ QUOTE ]
I've slipped 172's plenty of times.

[/ QUOTE ]

Me too.... but it only takes once.

I dunno; I was a big fan of slipping with flaps until I read it; just thought I'd put it up. It's the first concrete reason I've found to avoid slips, and it's a good one.
 

E_Dawg

Moderator
[ QUOTE ]
And if you do get out then all the blood in the water would attract a feeding frenzy of sharks.

[/ QUOTE ]

And those sharkes would attract jellyfish which would sting you sensless.
 

sbav8r

New Member
Then the waves would pound your bloddy beaten body against the coral before spitting you onto the 180 deg. sand.
 

E_Dawg

Moderator
which would then burn you to a fine ash residue which would be swept up, ironically, by your wake left by the slipstream....

All because you wanted to slip a Cessna. Now to me, that just dosen't.....
 

Baronman

Well-Known Member
Some Cessna POHs specifically make note of trying to avoid slips with flaps extended. Others make no mention of it. I frequently slip a 1978 C152 with up to 20 degrees extended.

Also keep in mind guys that a forward slip is not just a maneuver to loose huge amounts of altitude. That is to say that not every forward slip is full rudder deflection with 15 degrees of bank.

I doubt Cessna (or any other manufacturer) could certify an aircraft that demonstrated such consistent and violent reaction to a forward slip with some degree of flaps extended.
Just my $.02
 

ScorpionStinger

Well-Known Member
Belive it or not I'v actually done it with 30 degree flap extention( Back when i was training for PPL)

We generally landed with 30 degree of flaps; 95% of the time during my PPL training... When high he tells me to Slip.

Nothing in our 1980 C-152 POH against it...


If it's a very windy day .. Would it be okay to Do the slip with flaps extended and full Power???
 

E_Dawg

Moderator
[ QUOTE ]
Belive it or not I'v actually done it with 30 degree flap extention( Back when i was training for PPL)

We generally landed with 30 degree of flaps; 95% of the time during my PPL training... When high he tells me to Slip.

Nothing in our 1980 C-152 POH against it...


If it's a very windy day .. Would it be okay to Do the slip with flaps extended and full Power???


[/ QUOTE ]

Yeah I've slipped it plenty of times with 30* in there too (with no problems I might add).

And if it's windy I wouldn't use 30*, more like 20 at the most. However even with 30* I wouldn't hesitate to correct for the wind despite the supposed problems.

All I'm saying is that I'm going to think twice before I slip it for the hell of it, and I'm more likely to go around if I'm high than try to slip it.
 

ScorpionStinger

Well-Known Member
Hey R2F, how is it going. I'm not back yet(
)but in just 3 months we will be relieved and sent home. The "Tempo" is "Lower" now so We have more time to do other things.
This is an Addictive website you know

( My name is Scorpio11982, and I'm a Jetcaholic
)




Hey Skyguy, You are right about the go-around thing.

I said something wrong in my last post. I said my CFI
"Always" told me to Slip whenever i was to high... He did not always tell me to do that. I have performed Slips quite a few time with him, mostly during windy days.


P.s It Really sucks not flying for 3 months.. I feel like a fourlogh..
 

stultus

New Member
[ QUOTE ]
All I'm saying is that I'm going to think twice before I slip it for the hell of it, and I'm more likely to go around if I'm high than try to slip it.

[/ QUOTE ]

I've slipped a 150 with flaps a handful of times too...and now I think I'll be a little more cautious. Actually, I have been pretty cautious already--normally if it's not windy and I slip--I usually recover from the slip with time to put some flaps down before crossing the numbers. Is there anything wrong with that method? What about pitching the nose down and retracting the flaps before you enter a slip if you're too high? I've never tried it that way.
 

NJA_Capt

Well-Known Member
Unless I have overlooked something in the above posts. Some important considerations have been left out.

It is true that some single Cessnas are prohibited from slips with full flaps. However, some are not. We own a 1951 C170A which is approved for slips with all 50 degrees of flaps.

Early model C150/172s had 40 degrees of flap travel. I have long forgotten the changeover date, but somewhere in the 1970s Cessna changed from 40 degrees to 30 degree max flap travel. This was in response to the "problem" with tail stalls in the slip. Perhaps the man with the aggressive stall from slipping was doing so in a 40 degree flap airplane.

Used to love 40 degree flaps....you could make a heck of a short field landing


As always...read YOUR POH.
 

NJA_Capt

Well-Known Member
[ QUOTE ]
I usually recover from the slip with time to put some flaps down before crossing the numbers.

[/ QUOTE ]
I'm not sure why you would want to do this. It is an unnecessary configuration change VERY low to the ground. It requires moving the flaps and retrimming the elevator, when all that is necessary is easing out of the slip and flare.

[ QUOTE ]
What about pitching the nose down and retracting the flaps before you enter a slip if you're too high? I've never tried it that way.

[/ QUOTE ]
Easier to just go around. Again, this is an unnecessary configuration change. My preference is if you are going to slip, leave the flaps up. If you're using full flaps, don't slip.

The beauty of a slip is not needing to retrim much in a go around. Ever try a go around in a Cessna with full flaps and full trim? I do not recommend this for entertainment!
 

MidlifeFlyer

Well-Known Member
[ QUOTE ]
It is true that some single Cessnas are prohibited from slips with full flaps.

[/ QUOTE ] I'm new here and missed the discussion. So far, I haven't come across a Cessna single in which slips with full flaps was prohibited. Recommended against, yes, but prohibited, no.
 

NJA_Capt

Well-Known Member
[ QUOTE ]
So far, I haven't come across a Cessna single in which slips with full flaps was prohibited. Recommended against, yes, but prohibited, no.

[/ QUOTE ]

The first POH I just ran across is for a 1964 C172 with 40 deg of flaps, page 2-9, quote:

"LANDING
Normal landings are made power-off with any flap setting. Slips are prohibited (emphasis added) in full flap approaches because of downward pitch encountered under certain combinations of airspeed and sideslip angle."


Remember, it also is only recommended that you not poke your finger in your eye.
 
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