PA28-180 forward slips

C

clestudentpilot

Well-Known Member
I asked this question a few years, and didn't get a definative answer, and the debate has come up again. One of the airplanes that I fly is an older Piper Cherokee 180. The book I bought for it from the flight school says it is a "Cherokee B Owner's Manual." It is a 1963 model. The manual says nothing about any recommendations on slips. I know many 172's talk about avoiding them with more than 20 degrees of flaps. I also know an Archer I used to fly only talked about avoiding prolonged slips, unless it had full fuel. The Archer I used to fly was an older model Archer, so it was before they sweaked the wing shape. The only difference that I know of is that the wings are slightly longer in the Archer (30' span vs. 32' 2.5"). The stabilator is also slightly shorter in the Cherokee 180 (10' vs 12' 10.5").

Does anyone know if there are any limitations or recommendations for slipping a Cherokee 180 B? I have looked up the TCDS to see if there is anything in there, which there isn't. I don't see a placard in the airplane, but I know it is an older plane, things get worn and faded throughout the years. My assumption would be, since you can in the Archer, you can in the Cherokee, but as a buddy of mine said to me when we debated this "do you want to necessarily put your life in the hands of an asumption?" He wasn't arguing that there are any recommendations or limitations, or anything of the sort, just pointing out that neither of us know.

Thanks is advance
 
Just do it. If if does uncover a fuel pickup, all you have to do is take the rudder out, the engine comes right back. If you're worried about the tail, trust me even on the 172's you can do a full deflection slip for thousands of feet with 40* out. You get a slight buffet in the tail which you feel in the yoke, and that unnerves some people for some reason.
 
If its not in the book or an AD then it's not prohibited. If someone told me I could not do I slip in a certain airplane I would ask then to show me where it says that.
 
I understand the just do it mentality, I'm more looking for an official answer to the question. A friend of mine is getting ready for his check ride, and I have been quizzing him for his oral. I asked him about if he could do forward slips in that airplane. He said yes, and then I asked him to show me, which he couldn't. I already knew it wasn't in the POH, but it's actually bugging me now.

DL31082, I checked, there aren't any AD's relating to this in this airplane, and it's not in the POH. Is that actually true, that if it isn't in the POH or there isn't an AD on it, then there isn't a restriction on it? Again, I am just curious about anyone who has specific knowledge as to if it can or can't be done, and what restrictions, if any, there are on it
 
Is there anything specifically in the POH that says you're allowed to move the elevator on takeoff?
Is there anything that says you're allowed to bank past 5 degrees?

I suspect not. Yet, go fly an airplane without doing either of those.

The 180 was made when more common sense prevailed, and people in general weren't complete morons. Or at least people who fly weren't.
 
My point is read the manual.

We had an instructor teaching that you can't slip a DA20 with flaps out. When I asked him why he was teaching that he said because a Cessna can't be slip in that configuration. He in this case was wrong.

Waiting for someone else to say yes you can or no you can't is a waste of time when you have the information available. Not to mention the fact that just because someone else could have their facts wrong.
 
Normal op. if there is no AD, no placard, nothing in the POH... Totally ok.

And really- the worst thing that can possibly happen? The engine sputters. Who cares? If you are in a slip in the first place , you certainly should make the runway when you let it out.
 
Just don't stall it in a forward slip. Unlike a 172 where you just get a buffet a lose a bit of directional control. The low-wing will depart into an over-the-top spin entry. You'll have a lot of warning to before it happens though.
 
Point taken. I guess my experience with the 172 made me think that there must be some qualification, or quantification to do a forward slip. Thinking about it, all of you are right. If there was something bad about doing it, or something bad could happen, logic would say it would be in the POH, and AD, or a placard. I guess sometimes I want to make flying more difficult than it really is haha.
 
DL31082 said:
My point is read the manual.

We had an instructor teaching that you can't slip a DA20 with flaps out. When I asked him why he was teaching that he said because a Cessna can't be slip in that configuration. He in this case was wrong.

Waiting for someone else to say yes you can or no you can't is a waste of time when you have the information available. Not to mention the fact that just because someone else could have their facts wrong.
Click to expand...

I hope you also corrected him on the Skyhawk too.
 
Its been some time since I have flown a cessna. If I remember correctly the older cessnas with flap 40 have a limitation on slips. Its been awhile though I could be wrong.
 
I also believe the limitation on the 172 was "avoid", not "don't". I used to own one and all that would happen is a noticeable mild flutter in the yoke. I believe it was due to airflow disruption over the elevator. I never thought it was a big deal. I also own a 73 Cherokee 180 but have never slipped it. It drops like a rock with no power anyway and the flaps are a joke compared to a Cessna. But keep in mind that there were two totally different reasons for forward slip warnings between the Piper and the Cessna. Cessna was airflow disruption to the elevator and Piper was un-porting of a fuel tank.
 
DL31082 said:
Its been some time since I have flown a cessna. If I remember correctly the older cessnas with flap 40 have a limitation on slips. Its been awhile though I could be wrong.
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Yeah, it just says avoid, not prohibited.

If you ever have the chance to ride back seat during a full flap 172 slip you can really feel it and see a very slight shutter. I don't have the facts to back this up, but if I wasn't a pilot that would be a little disconcerting--maybe that's why they have avoid, passenger comfort:confused:
 
DE727UPS said:
I also believe the limitation on the 172 was "avoid", not "don't". I used to own one and all that would happen is a noticeable mild flutter in the yoke. I believe it was due to airflow disruption over the elevator. I never thought it was a big deal. I also own a 73 Cherokee 180 but have never slipped it. It drops like a rock with no power anyway and the flaps are a joke compared to a Cessna. But keep in mind that there were two totally different reasons for forward slip warnings between the Piper and the Cessna. Cessna was airflow disruption to the elevator and Piper was un-porting of a fuel tank.
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Seriously, the placard says "AVOID SLIPS WITH FLAPS EXTENDED" - not "don't do it ever!".
 
Ajax BU said:
I don't have the facts to back this up
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Some background: This book "Cessna Wings for the World" was written by William D. Thomson. He spent 28 years as the engineering test pilot and, later, as the Manager of Flight Test & Aerodynamics for Cessna.

Cessna Wings for the World - Page 41 said:
With the advent of the large slotted flaps in the C-170, C-180, and C-172 we encountered a nose down pitch in forward slips with the wing flaps deflected. In some cases it was sever enough to lift the pilot against his seat belt if he was slow in checking the motion. For this reason a caution note was placed in most of the owner's manuals under "Landings" reading "Slips should be avoided with flap setting greater than 30 degrees due to a downward pitch encountered under certain combinations of airspeed, side-slip angle, and center of gravity loading." Since wing-low drift correction in cross-wind landings is normally performed with a minimum flap setting (for better rudder control) this limitation did not apply to that maneuver. The cause of the pitching motion is the transition of a strong wing downwash over the tail in straight flight to a lessened downwash angle over part of the horizontal tail caused by the influence of a relative "upwash increment" from the upturned aileron in slipping flight. Although not stated in the owner's manuals, we privately encouraged flight instructors to explore these effects at high altitude, and to pass on the information to their students. This phenomenon was elusive and sometimes hard to duplicate, but it was thought that a pilot should be aware of its existence and know how to counteract it if it occurs close to the ground.

When the larger dorsal fin was adopted in the 1972 C-172L, this side-slip pitch phenomenon was eliminated, but the cautionary placard was retained. In the higher-powered C-172P and C-R172 the placard was applicable to a mild pitching "pumping" motion resulting from the flap outboard-end vortex impingement on the horizontal tail at some combination of side-slip angle, power, and airspeed.
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Emphasis added. Enjoy.
 
clestudentpilot said:
I understand the just do it mentality, I'm more looking for an official answer to the question. A friend of mine is getting ready for his check ride, and I have been quizzing him for his oral. I asked him about if he could do forward slips in that airplane. He said yes, and then I asked him to show me, which he couldn't. I already knew it wasn't in the POH, but it's actually bugging me now.

DL31082, I checked, there aren't any AD's relating to this in this airplane, and it's not in the POH. Is that actually true, that if it isn't in the POH or there isn't an AD on it, then there isn't a restriction on it? Again, I am just curious about anyone who has specific knowledge as to if it can or can't be done, and what restrictions, if any, there are on it
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You're asking the right question, but the first paragraph here is bugging me a little bit. You're not going to find a POH that says "Slips allowed in all flap configurations." You would have found a limitation if you've read the limitations section of the POH if it's actually prohibited. "Avoid" does not mean prohibited.

The other question you have to answer, if the slips are flat prohibited in a certain configuration, is how you land in a crosswind with that configuration. Aerodynamically, a forward slip and a side slip are the same.
 
shdw said:
Some background: This book "Cessna Wings for the World" was written by William D. Thomson. He spent 28 years as the engineering test pilot and, later, as the Manager of Flight Test & Aerodynamics for Cessna.



Emphasis added. Enjoy.
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Awesome, thanks for the info. Part of why I love this place :)
 
The OP said, "I don't see a placard in the airplane, but I know it is an older plane, things get worn and faded throughout the years."

You do know a missing placard renders the aircraft unairworthy, right?

Other than that, just do it. I've flown numerous older aircraft in the Cherokee line. None prohibit full slips.
 
RICHARD5 said:
The OP said, "I don't see a placard in the airplane, but I know it is an older plane, things get worn and faded throughout the years."

You do know a missing placard renders the aircraft unairworthy, right?

.
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Only if the placard was legally required to be there in the first place - I've seen some stupid stuff taped in cockpits before...
 
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