steep turns in the cherokee

[z987k]

A "Cherokee" can be anything from a 140 to an Arrow to a Six. Thats a lot of variance!

Never held one in a developed spin, just did incipient recoveries from different departure scenarios.

I realize that. Hence why I wondered what set the 140 apart to approve it for spins.

To understand why these limitations are put in place you need to look into the definition of what is considered "aerobatic flight" The issue is not a correctly flown maneuver. Even with the mild aerobatic maneuvers approved in the Cherokee, if flown badly, there is a potential for excessive pitch or bank possibly leading into and unusual attitude or spin where the recovery could quickly approach the normal category structural limitations.

Take aileron rolls, for example. There's nothing harmful happening to the airplane during a nicely executed aileron roll. Do it wrong and things will get ugly fast.

Ya, but a lazy 8 done even terribly, is all but normal flight.

 

[TwoTwoLeft]

I realize that. Hence why I wondered what set the 140 apart to approve it for spins.

During certification, the later models probably didn't demonstrate satisfactory recovery characteristics for spins to be approved. For these kinds of airplanes, pilots tend to favor things like more baggage load capacity & volume, more room for the rear seat occupants and better fuel range rather than an airplane engineered to be approved for spins. All these things change the "normal" CG limits and add farther combinations to test for certification. The manufacturer would rather placard "intentional spins prohibited" and provide the customer with an airplane that offers them more utility rather than try to spend more time and money to certify that airplane for spins in the aerobatic category.

 

[comstsa]

Thanks guys, good stuff.

 

[ndakcfi]

The issue is not a correctly flown maneuver. Even with the mild aerobatic maneuvers approved in the Cherokee, if flown badly, there is a potential for excessive pitch or bank possibly leading into and unusual attitude or spin where the recovery could quickly approach the normal category structural limitations.

Even if you do pretty much everything wrong during a lazy-8, the worst case scenario would probably be a stall happening with the aircraft in a shallow bank, which doesn't really explain limiting the maneuver to utility category.

If the assumption was that any maneuver could be done badly enough to over-G the airframe or enter a spin, I'd think that pretty much anything except sitting on the ramp would be limited to the utility category.

 

[TwoTwoLeft]

Even if you do pretty much everything wrong during a lazy-8, the worst case scenario would probably be a stall happening with the aircraft in a shallow bank, which doesn't really explain limiting the maneuver to utility category.

If the assumption was that any maneuver could be done badly enough to over-G the airframe or enter a spin, I'd think that pretty much anything except sitting on the ramp would be limited to the utility category.

I see the point you're making, but if you read the official definition of "aerobatic flight" you'll see the difference between the lazy eight and normal flight. The line has to be drawn somewhere, and "aerobatic" flight defines it.

 

[rframe]

I believe the current standard for a lazy eight, as a slow, smooth, shallow bank, shallow climb maneuver is not always how it was done. I've heard many older instructors (often with military backgrounds) taught/teach the lazy eight as a quick but smooth maneuver that is more like a wing over than the currently standard maneuver... if so, it would make sense why it was listed in the 60's and 70's flight manuals as an aerobatic maneuver.

 

[shdw]

I understand the 3.8 limit, but how do you calculate the load factor during specific degrees of bank?

Load factor in a turn = 1 / cosine (bank angle)

• 45 degrees = ~1.42G
• 60 degrees = 2G

That said, is this 'limitation' you refer to located in section 2 of your POH? And verbatum (word for word), what does it say? Reference the page number? Thank you.

 

[A150K]

I believe the current standard for a lazy eight, as a slow, smooth, shallow bank, shallow climb maneuver is not always how it was done. I've heard many older instructors (often with military backgrounds) taught/teach the lazy eight as a quick but smooth maneuver that is more like a wing over than the currently standard maneuver... if so, it would make sense why it was listed in the 60's and 70's flight manuals as an aerobatic maneuver.

The current standard for a lousy eight sucks. period.

In the words of one of our local DPEs, "If you are doing it right, the fun meter should read zero."

 

[juxtapilot]

Cherokee Warrior AFM Section 3-1
1. Maneuvers
a. Normal Category – All maneuvers including spins prohibited.
b. Utility Category – Approved maneuvers for Utility Category only.
i. Steep Turns
ii. Lazy Eights
iii. Chandelles
2. Placards
a. In full view of the pilot:
i. THIS AIRPLANE MUST BE OPERATED AS A NORMAL OR UTILITY CATEGORY AIRPLANE IN COMPLIANCE WITH THE OPERATING LIMITATIONS STATED IN THE FORM OF PLACARDS, MAKRINGS AND MANUALS.
ii. ALL MARKINGS AND PLACARDS ON THIS AIRPLANE APPLY TO ITS OPERATION AS A UTILITY CATEGORY AIRPLANE. FOR NORMAL AND UTILITY CATEGORY OPERATIONS REFER TO THE AIRPLANE FLIGHT MANUAL
iii. NO ACROBATIC MANEUVERS ARE APPROVED FOR NORMAL CATEGORY OPERATIONS. SPINS ARE PROHIBITED FOR NORMAL AND UTILITY CATEGORIES.

 

[nosehair]

I believe the current standard for a lazy eight, as a slow, smooth, shallow bank, shallow climb maneuver is not always how it was done.

This.
In the old days when those aircraft placards were common, they were not referring to present day PTS standards, but to the aerobatic standards, which were in the old Flight Training Handbook.

Steep Turn maneuvers were 60 degrees, the Lazy 8 & Chandelle were 60 degrees at steepest point.

 

[A150K]

This.
In the old days when those aircraft placards were common, they were not referring to present day PTS standards, but to the aerobatic standards, which were in the old Flight Training Handbook.

Steep Turn maneuvers were 60 degrees, the Lazy 8 & Chandelle were 60 degrees at steepest point.

Man...A lazy 8 would be so easy if they let you have 45 or 60 degrees of bank. There's nothing more painful than rolling out that last bit of bank beetween the 135 and 180 points if you got carried away beetween the 90 and 135.

 

[nosehair]

Man...A lazy 8 would be so easy if they let you have 45 or 60 degrees of bank. There's nothing more painful than rolling out that last bit of bank beetween the 135 and 180 points if you got carried away beetween the 90 and 135.

This is so true! The 45-60 degree banks taught more coordination at the higher performance (extreme) levels, but they were short-concentrated-focused moments like the last moments of a landing.
The current slow motion of the 15-30 degree banked lazy 8 drags out a totally different set of skills like being ahead of the airplane before the landing.

 

[shdw]

Cherokee Warrior AFM Section 3-1

Section 3 a misprint? Section 3 is typically Emergencies, was it different in older aircraft?

 

[Mike H]

Older aircraft POH's typically didnt follow the format we're familiar with and most had only the most basic information. Performance charts were, for the most part, nonexistent.

In a case like this, where the POH puts a prohibition on steep turns in the normal category I think it would be irresponsible (not to mention careless & reckless) to disregard the POH

 

[Houston]

The question I would ask is WHY would you want to expose yourself to the risk? Let's say 99% of the people agree it is okay to do. But, of all the bad luck, the person who calls it into question happens to be in the other 1%. What have you risked versus what have you gained.

There are plenty of opportunities to take friends and family on training flights that they will enjoy. Just skip the ones that have any associated question. Besides, a person would have to be a glutton for punishment to enjoy sitting in the back seat of a Piper while it does steep turn with a student at the controls.

 

[nosehair]

a person would have to be a glutton for punishment to enjoy sitting in the back seat of a Piper while it does steep turn with a student at the controls.

O-O-ooh, the gluttony !:disgust:

 

[A150K]

Older aircraft POH's typically didnt follow the format we're familiar with and most had only the most basic information. Performance charts were, for the most part, nonexistent.

In a case like this, where the POH puts a prohibition on steep turns in the normal category I think it would be irresponsible (not to mention careless & reckless) to disregard the POH

Or if you're like me and you rarley fly anything newer than a 1974 177RG, then you get confused and amazed with all the information in the newer format

Seriously, it is nice to have cruise performance numbers for many altitudes as opposed to a few. Looking at the POH for my 150 Aerobat, the only altitudes with performance information are 2.5, 5000, 7.5, 10,000, and 12.5.

 

[shdw]

The question I would ask is WHY would you want to expose yourself to the risk?

Agreed. For me, I would call the insurance company. After all Houston is correct on being exposed to a risk. Legally.

Structurally, a 45-50 degree steep turn is merely one and a half G, you are safe to fly steep turns. Basically anything that doesn't put you in a stall regime would be safe from a weight change and aft shift in CG. So stalls may be a separate issue, particularly power on stall. That's neither here nor there though, because stalls, of any kind (turning @30 degree bank), aren't prohibited with a guy in the back seat. Lazy 8's are...

Ok I wandered for the sake of . My point is simple, a steep turn to PPL standards is 1.42G, well within the 3.8G limit's of the category. I'd not be surprised if the term steep turn refers to aerobatic steep turns. See below:

From: http://www.wilgroveairport.net/files/Cherokee 140 POH.pdf -- Issued 1964 / Revised 73 -- page 18 -- Maneuvers:

"The airplane is approved for certain aerobatic maneuvers up to a gross weight of 1950lbs. The maneuvers are spins, steep turns, lazy eights and chandelles." (Emphasis added)

Maybe, maybe not. This is the kind of thing I'd bring to my insurance company. Aerobatic steep turn prohibition makes sense, 45 degree steep turn prohibition just makes me :rotfl:




*I'd follow the rules, but fight like hell to get permission if I felt it could be an educational benefit. And I do, but our cherokees are only 2 seaters. People still can't count as bagage, even if you use a sedative. I asked

 

[rframe]

People still can't count as bagage, even if you use a sedative. I asked

They can if they aren't breathing and are in a bag...an FBO I used to work for got several cargo charters for deceased people hauling. But, that's probably not going to help much from an educational standpoint.

 

[shdw]

They can if they aren't breathing and are in a bag...an FBO I used to work for got several cargo charters for deceased people hauling. But, that's probably not going to help much from an educational standpoint.

I really think that depends on the type of education you're providing. Catering to the mob could be a real money maker! :insane: