PA-28-181 flyers : What is your typical rate of climb?

RyanB

RyanB

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Color me ignorant, but after looking at the POH, I see that it says Vy yields a climb rate of about 670fpm, which I presume to be at sea level. What I don’t see is how this number is determined. Is that at max gross at sea level? I usually see about 800fpm with full fuel and two up depending on density altitude and such variables. Those of you who fly an Archer, what is your typical rate of climb?

Thanks!
 
I like POHs that have the climb rates with spaghetti charts, which allow for interpolations across weight as well, not just altitude. Rockwells and newer Beech formats are the cleanest. Old school piper is a mess, looks like the marketing dept team secretary's (they had those back then, #don't #cancel #me lol) toddler was tasked to draw some numbers on a pamphlet with the cartoon size crayons, the crayon fell and broke, and he drew with it anyways :D.

At any rate, if all you have is a single line, yeah it's at max gross. I've drawn comparisons with other POH of the same family (I can, since Arrows came in more than one flavor), to come up with a proxy of climb rate gain per 100 pounds below MGW. Came up to like 100ft/min gain per 150-200# loss. This works across all altitudes of course, since you have the value for all altitudes at MGW provided to you. You could even come up with increase in service ceiling for a lower weight as well, which I've empirically validated in my Arrow when flying solo (value which isn't published).

I bet you if you use the pa-28-161 MGW and interpolate, you'll come up with a similar rate of climb to weight loss ratio.
 
That has to be max gross. Otherwise the 670 fpm number sounds too low. My Archer performance sounds similar to your 800 fpm.

I might get 750 fpm @ 85 kts IAS up to 5 or 6k MSL maybe being 200 lbs under max TOW with no extreme density altitude, airport about 200' MSL.

As long as I am over 500 fpm then I am comfortable. When it goes less than 500 fpm than I start thinking maybe this is high enough.
 
Random tangent: modern avionics record so much information that it should, in theory, be possible to ingest data from all of an aircraft's flights and back these numbers out. The only component missing would be the current payload for each flight. Someone should write some software for this...
 
Mongoose Aviator said:
That has to be max gross. Otherwise the 670 fpm number sounds too low. My Archer performance sounds similar to your 800 fpm.

I might get 750 fpm @ 85 kts IAS up to 5 or 6k MSL maybe being 200 lbs under max TOW with no extreme density altitude, airport about 200' MSL.

As long as I am over 500 fpm then I am comfortable. When it goes less than 500 fpm than I start thinking maybe this is high enough.
Click to expand...
What year is your Archer? If I’ve got full fuel and two people (myself and a passenger), 800fpm or so is about average during the warmer spring/summer
months.
 
Eric Pauley said:
Random tangent: modern avionics record so much information that it should, in theory, be possible to ingest data from all of an aircraft's flights and back these numbers out. The only component missing would be the current payload for each flight. Someone should write some software for this...
Click to expand...
You can get some or all of the data you need to calculate rate of climb at different conditions, but determining best climb speeds requires a little more than dumping numbers from a climb or two. It's not difficult, but doesn't happen automatically. Coalescing data from random flights tends to get very messy - flying steady climbs to get the data is more reliable but tedious.

asicer said:
You can get GPS derived FPM. IAS still remains a challenge, though.
Click to expand...
Sometimes it's just as simple as writing the IAS you're flying on a piece of card stock. Call it a data card, or a flight card if you're a traditionalist. You'll also get more reliable results if you use your altimeter and a stopwatch for the climb rather than GPS ROC - although you can average GPS ROC over the climb period and get nearly the same number.

It's also possible to get good climb performance data by doing accelerations from low speed to high speed in level flight at a few altitudes and reducing the data using excess power relationships. I've been playing with that while testing recently, I may (or may not) post something on it in the near future, we'll see.

@RyanB if you're only given one value for Vy it's safe to assume it's at gross weight.

ETA: Note that the airspeed for best ROC *and* the ROC at that speed will change with weight, so if you're flying at Vy@gross but you're lighter you're giving up performance. How much? About that much.

Nauga,
and Ed Rutowsky
 
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Everything is closely dependent on weight, stall speeds, maneuvering speed, climb rates, etc. I think Piper expects a climb with 2 notches of flaps 25deg (on take-off) and not sure for how long, I usually reduce flaps slowly after 1000’ AGL.
 
At sea level, which is where I'm conveniently located, my Archer II can pretty consistently do 900fpm when not fully loaded, often more if it's a cool morning.
 
nauga said:
...if you're only given one value for Vy it's safe to assume it's at gross weight.
Click to expand...
d'oh...and also standard day sea level atmospheric conditions.

Nauga,
who isn't really retconning :)
 
From what I can recall I saw everything from 500fpm to almost 1500fpm depending on conditions and loading but average was probably somewhere between 700-1000. It really seems to depend on the day- temps/winds/aircraft weight.
 
Given most Archers are 1600# cans empty and 2550 gross, you're probably flying around circa 2300# (360ish# for two dodos and their 12 pounds of portable TV screens in the front, 288# for 48 usable in the tanks). That's 250 under gross, which by my TLAR gets you 175-200ft/min higher than MGW listed at standard temp. So call it 940fpm at SL DA best case, and decreasing from that zenith at the same slope as your POH MGW line.

That's perfectly congruent with your stated experience. Your engine is fine, you're making power and climbing about right for your weight and DA.

This whole discussion reminded me of my lusting years back, the F-4 Phantom approach as I call it: The comanche 400. Most ridiculous thing ever invented in this recreational piston space, and I still love the idea of it. Would almost be willing to take it on, if not for my sheer aversion to having to crack open an IO-720 for any reason at all. Makes a Seneca I pair of IO-360s with double the accessory count seem cheaper by comparison. This thing was ridiculous for a non-experimental 4-seater:
upload_2023-4-16_22-58-28.png

With the flaps and gear hanging and 1000 pounds more than my wheezy Arrow, it still passes over my laggard _ss at +300fpm. :D
 
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mandm said:
I think Piper expects a climb with 2 notches of flaps 25deg (on take-off) and not sure for how long, I usually reduce flaps slowly after 1000’ AGL.
Click to expand...
Do you have a POH source for that?

I would use first notch of flaps only for a short field take off. All standard take offs are with flaps fully retracted.

jrcox19 said:
At sea level, which is where I'm conveniently located, my Archer II can pretty consistently do 900fpm when not fully loaded, often more if it's a cool morning.
Click to expand...
At what IAS are you getting the 900 fpm climb?
 
"zoom climbs" anybody? (beetlejuice, beetlejuice....)
:stirpot:
 
RyanB said:
Color me ignorant, but after looking at the POH, I see that it says Vy yields a climb rate of about 670fpm, which I presume to be at sea level. What I don’t see is how this number is determined. Is that at max gross at sea level? I usually see about 800fpm with full fuel and two up depending on density altitude and such variables. Those of you who fly an Archer, what is your typical rate of climb?

Thanks!
Click to expand...
Depends on if I have the AC on or not, and how freaking hot it is in Houston that day. 700 fpm is pretty reasonable, though. That's what I plan for.
 
JVerb said:
Depends on if I have the AC on or not, and how freaking hot it is in Houston that day.
Click to expand...
Initial climb out at full power should have the AC off. Checklist calls for it to be off as well there is supposed to be a microswitch on the throttle that at full throttle also turns the AC off.
 
asicer said:
You can get GPS derived FPM. IAS still remains a challenge, though.
Click to expand...
My engine monitor doesn't talk to my panel-mounted GPS, and the GPS doesn't record its flight path data. I have a tablet-based EFB that does record flight path data, but it's not integrated with the engine monitor. So yeah, some of the data is there, but it's not all in one conveniently consumable location or format.
 
Jim_R said:
My engine monitor doesn't talk to my panel-mounted GPS, and the GPS doesn't record its flight path data. I have a tablet-based EFB that does record flight path data, but it's not integrated with the engine monitor. So yeah, some of the data is there, but it's not all in one conveniently consumable location or format.
Click to expand...
Technology can make complex things easy, but it can also make easy things very complex. TLDR: If the point some of you are trying to make is that you can’t get climb performance from a standalone engine monitor, then you’re absolutely right. Full Stop.

If you’re frustrated that you can’t get climb performance from a standalone engine monitor, it’s almost trivial *without* an EMS/EFIS/GPS/whatever in even a steam gauge cockpit. It does, however, require dedicated testing, but so does testing using digital sources of data.

Say you want to know climb performance at Vy given in the POH at gross weight, standard day conditions.
Tools needed: Airplane, pilot, stopwatch.
Pick the airspeed and altitude you want data for, a typical test would calc RoC through a climb +/- 500 ft of that altitude while stabilized at the test airspeed.

Before flight:
  1. Make sure your weight and balance is good. Climb data is useless without knowing the weight at which it was tested. There’s a large tolerance but why give away accuracy?
  2. Write a card with the steps you want to do, in order and in large print that you can read at a glance. Also include spaces to write down the test data in the test steps. At the top of the test write the test altitude and airspeed.
  3. Try to pick a day with decent conditions. Steady wind through the test altitude band does not affect the data, but climbing through a wind gradient or turbulence will.
In flight:
  1. Set your altimeter to 29.92 (to get pressure altitude). I use a standby altimeter for this.
  2. Stabilize at ~700 ft below the test altitude.
  3. Stabilize a few knots below the test airspeed and apply full throttle.
  4. At or near your test airspeed begin pulling up and trimming in a climb. If you’re accelerating, increase pitch attitude. If decelerating, decrease pitch attitude. *Don’t* reduce the throttle.
  5. Passing through 500 ft below the test altitude start the stopwatch. If you’re not stabilized on your test airspeed, knock it off, reset, and try again. You can start as low as you need to to give you time to stabilize in the climb as long as you’re stabilized passing the 500 ft below mark.
  6. Continue the climb while maintaining test airspeed. Ideally it would be held within ±2 kt but ±5 kt might be sufficient depending on your target airspeed, lower requiring tighter tolerance. If you’re well stabilized but at a different airspeed you can continue the test for the trimmed speed but FFS WRITE IT DOWN! Whatever value you can eyeball average on any normal airspeed indicator is good enough.
  7. Passing the test altitude note the airspeed (see above) and whatever data you need to estimate weight (like fuel qty) and power (pressure altitude, manifold pressure, RPM, OAT, etc.) Don’t stop climbing yet. You can also have a passenger write down the data or use a voice recorder or camera.
  8. Maintain the airspeed throughout a climb to 500 ft above test altitude. Passing the +500ft mark note the time on the stopwatch.
  9. Pencils down, test is over. Repeat, or pick different conditions, ad nauseum.
  10. Don't forget to reset the altimeter, if necessary.
Post flight:
  1. Altitude band (1000 ft)/time in sec noted on stopwatch * 60 = RoC in FPM at that airspeed and pressure altitude at test day OAT, weight, and power. Boom, done, unless you want to convert to calibrated auirpseed. You can repeat at a range of airspeeds and/or weights to see how off-book conditions change the RoC available, and to see if maybe your airplane really *is* a dog.
You can uses digital data as sources for much of the stuff you're writing down if you have it available, but you might find that it's more trouble than it's worth. Having said all that, I record a crap-ton of data from my avionics and other sources for flight test purposes including climb performance because I can do it much faster with the digital data than with ‘handheld’ data as presented above. I’m happy to discuss what and how I do for those who might be interested, but it’s not something at TC’d airplane owner should ever need to do and something most Ex/AB builders can work around.

Nauga,
and the victimless climb
 
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The Twenty Eight One Eighty I used to instruct in. Would give us a hearty eight hundred FPM climb with a crew of two and full fuel. Climbing 400’ to 5000 MSL.
 
nauga said:
Technology can make complex things easy, but it can also make easy things very complex. TLDR: If the point some of you are trying to make is that you can’t get climb performance from a standalone engine monitor, then you’re absolutely right. Full Stop.

If you’re frustrated that you can’t get climb performance from a standalone engine monitor, it’s almost trivial *without* an EMS/EFIS/GPS/whatever in even a steam gauge cockpit. It does, however, require dedicated testing, but so does testing using digital sources of data.

Say you want to know climb performance at Vy given in the POH at gross weight, standard day conditions.
Tools needed: Airplane, pilot, stopwatch.
Pick the airspeed and altitude you want data for, a typical test would calc RoC through a climb +/- 500 ft of that altitude while stabilized at the test airspeed.

Before flight:
  1. Make sure your weight and balance is good. Climb data is useless without knowing the weight at which it was tested. There’s a large tolerance but why give away accuracy?
  2. Write a card with the steps you want to do, in order and in large print that you can read at a glance. Also include spaces to write down the test data in the test steps. At the top of the test write the test altitude and airspeed.
  3. Try to pick a day with decent conditions. Steady wind through the test altitude band does not affect the data, but climbing through a wind gradient or turbulence will.
In flight:
  1. Set your altimeter to 29.92 (to get pressure altitude). I use a standby altimeter for this.
  2. Stabilize at ~700 ft below the test altitude.
  3. Stabilize a few knots below the test airspeed and apply full throttle.
  4. At or near your test airspeed begin pulling up and trimming in a climb. If you’re accelerating, increase pitch attitude. If decelerating, decrease pitch attitude. *Don’t* reduce the throttle.
  5. Passing through 500 ft below the test altitude start the stopwatch. If you’re not stabilized on your test airspeed, knock it off, reset, and try again. You can start as low as you need to to give you time to stabilize in the climb as long as you’re stabilized passing the 500 ft below mark.
  6. Continue the climb while maintaining test airspeed. Ideally it would be held within ±2 kt but ±5 kt might be sufficient depending on your target airspeed, lower requiring tighter tolerance. If you’re well stabilized but at a different airspeed you can continue the test for the trimmed speed but FFS WRITE IT DOWN! Whatever value you can eyeball average on any normal airspeed indicator is good enough.
  7. Passing the test altitude note the airspeed (see above) and whatever data you need to estimate weight (like fuel qty) and power (pressure altitude, manifold pressure, RPM, OAT, etc.) Don’t stop climbing yet. You can also have a passenger write down the data or use a voice recorder or camera.
  8. Maintain the airspeed throughout a climb to 500 ft above test altitude. Passing the +500ft mark note the time on the stopwatch.
  9. Pencils down, test is over. Repeat, or pick different conditions, ad nauseum.
  10. Don't forget to reset the altimeter, if necessary.
Post flight:
  1. Altitude band (1000 ft)/time in sec noted on stopwatch * 60 = RoC in FPM at that airspeed and pressure altitude at test day OAT, weight, and power. Boom, done, unless you want to convert to calibrated auirpseed. You can repeat at a range of airspeeds and/or weights to see how off-book conditions change the RoC available, and to see if maybe your airplane really *is* a dog.
You can uses digital data as sources for much of the stuff you're writing down if you have it available, but you might find that it's more trouble than it's worth. Having said all that, I record a crap-ton of data from my avionics and other sources for flight test purposes including climb performance because I can do it much faster with the digital data than with ‘handheld’ data as presented above. I’m happy to discuss what and how I do for those who might be interested, but it’s not something at TC’d airplane owner should ever need to do and something most Ex/AB builders can work around.

Nauga,
and the victimless climb
Click to expand...
One more option: After I posted, I remembered that my engine monitor does record "Manifold Pressure". Since my plane is naturally-aspirated, the MAP reading is just ambient air pressure. This could also be used as a proxy for altitude, and with some math, could be used to derive a(n approximate) rate of climb.
 
Jim_R said:
One more option: After I posted, I remembered that my engine monitor does record "Manifold Pressure". Since my plane is naturally-aspirated, the MAP reading is just ambient air pressure. This could also be used as a proxy for altitude, and with some math, could be used to derive a(n approximate) rate of climb.
Click to expand...
MAP is not just ambient pressure, even on a NA airplane, as long as the engine is running. Even if it were, the noise in a typical MAP reading from a typical sensor on a typical (NA) engine is going to result in crap RoC data if you're thinking of numerically differentiating it. Why not just use your altimeter?

Nauga,
carpe datum
 
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