Piper Cherokee shortfield question

itsjames2011

itsjames2011

Pre-takeoff checklist
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James
I own a 1964 Piper Cherokee 140. The only take off performance chart that is listed in the 1964 manual assumes 0 degrees flaps, brakes applied, and full throttle. There is nothing in the book to indicate flaps for a short field take off.

The million dollar question for me is in the case of a Cherokee with a Hershey bar weigh, does 25 degrees of flaps help or hurt in a climb to clear a 50 foot obstacle?


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I used 25 degree of flaps in my 77 Arrow but it had the tapered wing and that was what was in the POH, You should follow your POH,
 
If you're on a checkride, use the book. Otherwise, go out an experiment and see which method works better.
 
Did it not come with an "Owner's Handbook?"

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kgruber said:
Did it not come with an "Owner's Handbook?"

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Click to expand...
It came with the original 1964 pilot operating handbook. The book sucks, is missing tons of information compared to today's standard of manuals, and doesn't even specify short/soft field procedures

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POH I have for a Cherokee 140 states 25 deg flaps and 74mph climb speed for short field obstacle clearance take off. This is in section III, page 17 of the POH issued Feb '64 and revised Jan '73.


-----Edit------

I went back and looked at the cover. It is titled "Owner's Handbook".
 
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Early Cherokees (including my 1969) did not have a POH but an AFM. Very limited information, certainly nothing like we're used to these days. And really poor quality copy of the original document that lives at Piper. I called one day to get a clean copy and was told all they had were poor copies of the microfiche of the AFM.
 
I'm sorry it is the airplane flight manual. It's a piece of crap. Here's a pic.
uploadfromtaptalk1440461777926.jpg

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Is there an aftermarket book for my serial number that has more information?

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25degrees of flaps stay in ground effect until 74(vx) and climb out at 74
 
Have to retract flaps at some point, right? As I recall, Vx climb was with flaps 10. 25 degrees of flaps is too much drag.

Could be remembering wrong.
 
bflynn said:
Have to retract flaps at some point, right? As I recall, Vx climb was with flaps 10. 25 degrees of flaps is too much drag.

Could be remembering wrong.
Click to expand...

It's 25 retract flaps when clear of obstacle and climb remaining alt at vy.
 
kgruber said:
They ALSO came with the "Owner's Handbook." As seen in post #4, with all the relevant short field information.
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If so, news to me. I have every document for my cherokee, even contacted Piper years ago, and they confirmed there's no Owner's Handbook, only the AFM. The Owner's Handbook is/was a very generic booklet. Yes, it has instructions for events such as preflight, emergency procedures, multiple charts, but because so generic, not legal as POH or AFM.

If it were gospel, I would rarely be allowed to fly because the charts only go to 7000 ft, and right now, even after midnight, my DA is more than 7000 ft.
 
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SkyDog58 said:
That sounds more like soft field. The question was about short field.
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Vx is the best angle of climb (74)
Vy is the best rate of climb (85) I believe in the book it's 85 but we use 95 for better visibility and airflow to the engine.

This is for the Cherokee 140

Short field over 50ft obstacle: 25 degrees set brakes full throttle ground effect until vx climb at vx until obstacle is clear than slowly remove flaps and climb at VY.

Soft field no obstacle: 25 degrees ground effect until vx slowly remove flaps climb out at vy

To answer op flaps question I say it helps tremendously. Around vx you have to start applying forward pressure on the yoke to maintain airspeed. As soon as you do that you can really seat of the pants feel the climb.
 
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MotoFlier said:
Vx is the best angle of climb (74)
Vy is the best rate of climb (85) I believe in the book it's 95 but we use 85 for better visibility and airflow to the engine.

This is for the Cherokee 140

Short field over 50ft obstacle: 25 degrees set brakes full throttle ground effect until vx climb at vx until obstacle is clear than slowly remove flaps and climb at VY.

Soft field no obstacle: 25 degrees ground effect until vx slowly remove flaps climb out at vy

To answer op flaps question I say it helps tremendously. Around vx you have to start applying forward pressure on the yoke to maintain airspeed. As soon as you do that you can really seat of the pants feel the climb.
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How does a slower airspeed which normally means higher AOA give you better visibility and airflow to the engine? Normally the opposite is true. :dunno:
 
SkyDog58 said:
How does a slower airspeed which normally means higher AOA give you better visibility and airflow to the engine? Normally the opposite is true. :dunno:
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2am typo lol
 
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I used to add 25* right before rotate for short field operations. Gives a good "shot off the bow".
 
Two notches for short field in a Cherokee at Vx. Don't overthink it.

Take a notch out after the 50 foot obstacle, climb at Vy from there.
 
SkyDog58 said:
That sounds more like soft field. The question was about short field.
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Staying in ground effect would be soft field. I don't stay in ground effect, but I do put the nose down fairly soon after lift off to get to Vx as quickly as possible. Then climb from there. That's probably what he means.
 
For short field I used to do a no flap takeoff transitioning to Vx on climb out. For soft field I'd do one notch of flaps (Cherokees use a Johnson bar actuator that does not read out in degrees), accelerate in ground effect and then climb out at Vy, or Vx if there were an obstacle.

Best thing is to fart around with your own airplane. The book describes the performance of a brand new airplane. Yours might differ significantly.
 
steingar said:
For short field I used to do a no flap takeoff transitioning to Vx on climb out. For soft field I'd do one notch of flaps (Cherokees use a Johnson bar actuator that does not read out in degrees), accelerate in ground effect and then climb out at Vy, or Vx if there were an obstacle.

Best thing is to fart around with your own airplane. The book describes the performance of a brand new airplane. Yours might differ significantly.
Click to expand...

The Johnson bar has three positions: 10 deg, 25 deg and 40 deg.

Soft fields especially work a LOT better with 25 flaps than with 10.
 
pilot_dude said:
I used to add 25* right before rotate for short field operations. Gives a good "shot off the bow".
Click to expand...

This. Mine would leap off the ground like a homesick angel.
 
SkyDog58 said:
But then those flaps at 25 degrees turn into massive spoilers. Not good. :no:
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I was taught that either way is ok. The objective on short field is to accelerate to Vx as quickly as possible, which means getting off the ground as quickly as possible but keeping the angle of attack low enough to accelerate rapidly.

Two notches is the POH procedure (at least in Hershey Bar Cherokees). The second notch still provides significant extra lift. It's that third notch that does nothing but drag. That's why you drop the third notch immediately on a go around but leave two on until clear of obstacles and established in positive rate of climb.
 
wilkersk said:
POH I have for a Cherokee 140 states 25 deg flaps and 74mph climb speed for short field obstacle clearance take off. This is in section III, page 17 of the POH issued Feb '64 and revised Jan '73.


-----Edit------

I went back and looked at the cover. It is titled "Owner's Handbook".
Click to expand...

This. Two notches, 75 mph, bleed off the flaps once you've cleared the obstacle.
 
I'm looking at a Cherokee Warrior II Information Manual. (This model has the tapered wing)

Short field obstacle clearance is:
Flaps 25* (second notch)
Rotate at 52 Knots. Maintain 52kias until obstacle cleared.
Accelerate to 79 knots, then retract flaps slowly,.

Short field, NO obstacle:
Flaps UP
Rotate at 50 knots
accelerate to best climb 79 knots.
 
itsjames2011 said:
I own a 1964 Piper Cherokee 140. The only take off performance chart that is listed in the 1964 manual assumes 0 degrees flaps, brakes applied, and full throttle. There is nothing in the book to indicate flaps for a short field take off.

The million dollar question for me is in the case of a Cherokee with a Hershey bar weigh, does 25 degrees of flaps help or hurt in a climb to clear a 50 foot obstacle?


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Click to expand...

I was getting a rental checkout in an Arrow a couple years ago. Wing and flap system similar to yours. He taught me this. Do the take off roll no flaps, then reach down and grab the the first notch at lift off. Don't know if it really got us over the fence any higher. Don't think I would've tried this just because someone told me about though. It got us right on up. It would be a good experiment to run. Two in the cockpit, one flying and looking at the altimeter when the other calls out over a spot on the ground where the 50' obstacle would be
 
Skip Miller said:
I'm looking at a Cherokee Warrior II Information Manual. (This model has the tapered wing)

Short field obstacle clearance is:
Flaps 25* (second notch)
Rotate at 52 Knots. Maintain 52kias until obstacle cleared.
Accelerate to 79 knots, then retract flaps slowly,.

Short field, NO obstacle:
Flaps UP
Rotate at 50 knots
accelerate to best climb 79 knots.
Click to expand...

And your question is?
 
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