SGOTI got in my head

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morleyz

Pre-takeoff checklist
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I was watching a Pilot Debrief from Hoover on Facebook about a sea plane that stalled on take off and crashed. SGOTI posted that if the pilot had just kept the standard 3-degrees or less of climb angle he wouldn't have stalled. Now, he's probably technically correct that the plane wouldn't have stalled at that very low angle, but probably would have hit the trees. Anyway, we got into a back and forth where I said you climb out at airspeeds and I don't really pay attention to the degree markers on the AI. Guy says this is not true for sea planes and he owns and flies a c185 seaplane (which I'm now never allowed to fly :p) and he always climbs at precisely 3 degrees as marked on his AI.

Anyway, everyone here is smarter than me and SGOTI. I'm assuming because I read through the POH and the AFH again a few times that I'm going to keep flying my departures by accelerating and pitching for Vx or Vy depending on the situation to climb out. That being said, is there any plane, situation, etc. where you're actually recommended to fly at X degrees on the AI? I can't think of one, but I'm just a lowly PPL flying bugsmashers around the country side.
 
morleyz said:
I was watching a Pilot Debrief from Hoover on Facebook about a sea plane that stalled on take off and crashed. SGOTI posted that if the pilot had just kept the standard 3-degrees or less of climb angle he wouldn't have stalled. Now, he's probably technically correct that the plane wouldn't have stalled at that very low angle, but probably would have hit the trees. Anyway, we got into a back and forth where I said you climb out at airspeeds and I don't really pay attention to the degree markers on the AI. Guy says this is not true for sea planes and he owns and flies a c185 seaplane (which I'm now never allowed to fly :p) and he always climbs at precisely 3 degrees as marked on his AI.

Anyway, everyone here is smarter than me and SGOTI. I'm assuming because I read through the POH and the AFH again a few times that I'm going to keep flying my departures by accelerating and pitching for Vx or Vy depending on the situation to climb out. That being said, is there any plane, situation, etc. where you're actually recommended to fly at X degrees on the AI? I can't think of one, but I'm just a lowly PPL flying bugsmashers around the country side.
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Holding a pitch attitude is done in IFR flying a lot. You cross check air speed and vertical speed and use throttle to maintain the speeds you want.
 
morleyz said:
I was watching a Pilot Debrief from Hoover on Facebook about a sea plane that stalled on take off and crashed. SGOTI posted that if the pilot had just kept the standard 3-degrees or less of climb angle he wouldn't have stalled. Now, he's probably technically correct that the plane wouldn't have stalled at that very low angle, but probably would have hit the trees. Anyway, we got into a back and forth where I said you climb out at airspeeds and I don't really pay attention to the degree markers on the AI. Guy says this is not true for sea planes and he owns and flies a c185 seaplane (which I'm now never allowed to fly :p) and he always climbs at precisely 3 degrees as marked on his AI.

Anyway, everyone here is smarter than me and SGOTI. I'm assuming because I read through the POH and the AFH again a few times that I'm going to keep flying my departures by accelerating and pitching for Vx or Vy depending on the situation to climb out. That being said, is there any plane, situation, etc. where you're actually recommended to fly at X degrees on the AI? I can't think of one, but I'm just a lowly PPL flying bugsmashers around the country side.
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My POH doesn't give a specific degree for initial climb out (it gives Vx/Vy as you'd expect), but it does say that it recommends a faster cruise climb of 110 specifically to improve visibility over the nose... Which at least acknowledges pitch being a non-negligible factor (only for visual reasons).
 
luvflyin said:
Holding a pitch attitude is done in IFR flying a lot. You cross check air speed and vertical speed and use throttle to maintain the speeds you want.
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I wasn't suggesting pitch attitude isn't important. I was more asking does anything, plane, operation, procedure, etc. say climb at 3 degrees, climb at 5 degrees, etc.? My thinking being on a high DA day or something, specifying an angle in degrees like that could be troublesome for a similar reason you don't climb trying to maintain a specific vertical speed.
 
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ArrowFlyer86 said:
My POH doesn't give a specific degree for initial climb out (it gives Vx/Vy as you'd expect), but it does say that it recommends a faster cruise climb of 110 specifically to improve visibility over the nose... Which at least acknowledges pitch being a non-negligible factor (only for visual reasons).
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We have the same plane. Lol. But the same question, have you run across anything that specifies degrees of pitch to maintain?
 
Guy on the internet may climb that way, but most don’t


Heck my plane doesn’t even have a attitude indicator, nor do many of the 2 place seaplanes.

Old sayin’ aim for the trees don’t try to mush over them

Energy is life, the runway you leave in front of you can be worse than the runway you leave behind you
 
morleyz said:
We have the same plane.
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Nice.

morleyz said:
have you run across anything that specifies degrees of pitch to maintain?
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No. And based on my experience it wouldn't make a lot of sense...
Flying in winter, just me in the plane -- I can climb at an aggressive angle and maintain Vy. If I try to climb at the same angle in the summer at max gross we're gonna nose over and eat sh*t into the ground.
 
I have no idea who SGOTI is. About the biggest aircraft I fly is a 206, Or the Columbia 400 for most horsepower. My understanding is that bigger/higher performance aircraft are flown by angle of attack. Most actually have good angle of attack indicators for doing so. Some may use the attitude indicator, especially bigger aircraft that don't maneuver a lot as this would be a good substitute for an actual angle of attack indicator as long as you are flying mostly straight.

The basic aerodynamic principle is that Vx and Vy speed pretty much always occur at the same angle of attack. If you have a don't significantly change the power or weight so much as to significantly change the angle you are actually climbing the Attitude indicator will be a relatively good substitute for an Angle of Attack indicator. In this scenario the Attitude indicator is probably a slightly better indicator than the Airspeed indicator as it accounts for weight and some power changes perhaps better than the airspeed indicator.

Probably the Attitude indicator in anything you fly isn't a required piece of equipment so it makes sense the POH would not reference it for climb for performance speeds. Plus most Attitude indicatora we fly with in our small singles don't usually have the resolution to really accurately fly a 3degree climb. Also the POH usually uses an average speed and the speed will change with weight. Some manual may list speeds at different weights.

On the other hand the power and weight changes available for a 185 aren't really enough to change the performance airspeeds very much, or if it does I am sure it listed in the POH.

I did a flight review for a guy in his light sport cub once. The only thing I noted is he told me he was tone deaf and could NOT hear the stall warning. As we finished up we stopped at a nearby airport and topped off the fuel tanks and then flew back to his 900ft private strip. On final I noted he slowed it down to 50mph and I heard him say 50mph (as his target), at this speed we were a bit nose high and the stall warning was just squeaking. Slower than I would have approach, but I know some back country guys like to approach like this. At about 10 feet he initiated a go around. I though It looked ok, not the way I would do it but would have worked. 2nd approach was exactly the same, with the go around. At which point he asked me what he was doing wrong. So I advised to approach at 60mph. As soon as we turned final he says that looked much better and landed just fine.

In the post flight debrief we figured out that he only flies solo and 50mph works well for him but we added my 200+ lbs and topped off the full on the light cub 50mph pitched the nose up so much it didn't look right to him, and with some justification( if he wasn't expecting it the plane could have dropped hard onto the runway) he initiated the go arounds. Basically he was using the windshield/horizon as an angle of attack indicator and could tell something wasn't right.

Brian
CFIIG/ASEL
 
ArrowFlyer86 said:
Nice.


No. And based on my experience it wouldn't make a lot of sense...
Flying in winter, just me in the plane -- I can climb at an aggressive angle and maintain Vy. If I try to climb at the same angle in the summer at max gross we're gonna nose over and eat sh*t into the ground.
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This is all to say that if someone told me to climb at a specific angle I would be inclined to ask: under what conditions?
 
morleyz said:
Lol, that's exactly what I asked. He said in a seaplane, always.
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I’d ask him to show you in the seaplane supplement (it ain’t there)

IMG-6235.jpg
 
morleyz said:
Lol, that's exactly what I asked. He said in a seaplane, always.
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Once you're off the ground, err water, a seaplane is just a plane. Same physics for all of us :)
Maybe there's some weird heuristic about how you want to climb out of water, like don't want the floats to come out too quickly (or slowly) or something. IDK. I'm just a lowly ASEL pilot so their stuff is all magic to me.
 
The floats will affect Vx and Vy. But there will still be a Vx and Vy appropriate with the floats.

Shut off the engine and climb at 3 degrees and see what happens.
 
I could see holding a specific pitch attitude during the takeoff run to hold the floats at the optimum angle on the water, but once airborne and climbing after any pause to accelerate in ground effect, holding an airspeed, like Vx or Vy, makes more sense.

Does the AI even have the resolution to tell between 3° or 5°?
 
morleyz said:
I wasn't suggesting pitch attitude isn't important. I was more asking does anything, plane, operation, procedure, etc. say climb at 3 degrees, climb at 5 degrees, etc.? My thinking being on a high DA day or something, specifying an angle in degrees like that could be troublesome for a similar reason you don't climb trying to maintain a specific vertical speed.
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I haven’t run across anything that actually gives it in ‘degrees.’ It’s ‘dots’ above the horizon.
 
morleyz said:
SGOTI posted that if the pilot had just kept the standard 3-degrees or less of climb angle he wouldn't have stalled. Now, he's probably technically correct that the plane wouldn't have stalled at that very low angle, but probably would have hit the trees. Anyway, we got into a back and forth where I said you climb out at airspeeds and I don't really pay attention to the degree markers on the AI. Guy says this is not true for sea planes and he owns and flies a c185 seaplane (which I'm now never allowed to fly :p) and he always climbs at precisely 3 degrees as marked on his AI.
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I think I've argued with that guy too. :rofl:
morleyz said:
I'm assuming because I read through the POH and the AFH again a few times that I'm going to keep flying my departures by accelerating and pitching for Vx or Vy depending on the situation to climb out. That being said, is there any plane, situation, etc. where you're actually recommended to fly at X degrees on the AI? I can't think of one, but I'm just a lowly PPL flying bugsmashers around the country side.
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Not to my knowledge. Some bigger planes will have a certain pitch angle that's used for takeoff, but that's just a starting point and you transition to airspeed almost immediately. (Positive rate, gear up, accelerate to airspeed and go).

There's also instrument departures where you have to maintain a certain climb gradient, but that's not degrees on the AI, it's feet per nautical mile.
brcase said:
I have no idea who SGOTI is.
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Some Guy On The Internet.
brcase said:
The basic aerodynamic principle is that Vx and Vy speed pretty much always occur at the same angle of attack.
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Really?? That doesn't make sense to me. Once established in the climb (ie, no vertical acceleration), the weight of the aircraft is the same in both cases and for the climb to remain vertically unaccelerated you need lift to equal weight, thus you need equal lift for both Vx and Vy. Since Vx is slower, your AoA needs to be higher to develop the same lift.

The only way this wouldn't be true is if the vertical component of thrust is the sole difference between Vx and Vy, but I can't believe that's true for all airplanes.
brcase said:
If you have a don't significantly change the power or weight so much as to significantly change the angle you are actually climbing the Attitude indicator will be a relatively good substitute for an Angle of Attack indicator. In this scenario the Attitude indicator is probably a slightly better indicator than the Airspeed indicator as it accounts for weight and some power changes perhaps better than the airspeed indicator.
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I would say that's maybe true in turbulence, but at different altitudes (DA), different weights, etc the optimum pitch attitude is going to vary. You would have to establish pitch using airspeed and then maintain whatever pitch that happens to be, not just use 3º every time.
brcase said:
Also the POH usually uses an average speed and the speed will change with weight. Some manual may list speeds at different weights.
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POH speed is for maximum gross weight, unless it's given for multiple weights. You can calculate the adjusted-for-weight version of most airspeeds by multiplying by the square root of the quotient of actual weight vs max gross. IE, 3600 pound max airplane being flown at 3000 pounds, sqrt(30/36) * Vwhatever.

ArrowFlyer86 said:
Once you're off the ground, err water, a seaplane is just a plane. Same physics for all of us :)
Maybe there's some weird heuristic about how you want to climb out of water, like don't want the floats to come out too quickly (or slowly) or something. IDK. I'm just a lowly ASEL pilot so their stuff is all magic to me.
Click to expand...
There is an optimum angle while you're still on the water, but you're correct that once in the air, it's just an AIRplane. The floaty ones just have a bunch of extra weight and drag on 'em.

On the water, you start with full aft stick, full power, and it'll pitch up at which point you let the nose back down. Now you're on the step. While there, if your pitch is too low you won't be developing enough lift and thus the floats will have to displace more water to hold you up and you'll never get to takeoff speed. If your pitch is too high you've got too much aero drag and might be putting the back end of the floats back into the water again, which again means more drag and you'll never get to takeoff speed. Gotta keep it just right, right in the middle. And if you're flying something less overpowered than a C185, if you don't do it right you'll just have a very expensive boat. Even a Super Cub will just barely get off the water (well, when it's carrying ME anyway :rofl:). You can "encourage" it with a quick tug when you're close to the max speed you'll get on the water and that might give you enough of a bump in lift to get the floats out of the water, which removes a TON of drag and lets you start flying, kinda. You're still in "water effect" and need to stay there for a few seconds just like on a soft field takeoff. You can feel the drag going away, though, because as soon as you're out of the water it'll surge forward. Fun stuff!
 
flyingcheesehead said:
I think I've argued with that guy too. :rofl:

Not to my knowledge. Some bigger planes will have a certain pitch angle that's used for takeoff, but that's just a starting point and you transition to airspeed almost immediately. (Positive rate, gear up, accelerate to airspeed and go).

There's also instrument departures where you have to maintain a certain climb gradient, but that's not degrees on the AI, it's feet per nautical mile.

Some Guy On The Internet.

Really?? That doesn't make sense to me. Once established in the climb (ie, no vertical acceleration), the weight of the aircraft is the same in both cases and for the climb to remain vertically unaccelerated you need lift to equal weight, thus you need equal lift for both Vx and Vy. Since Vx is slower, your AoA needs to be higher to develop the same lift.

The only way this wouldn't be true is if the vertical component of thrust is the sole difference between Vx and Vy, but I can't believe that's true for all airplanes.

I would say that's maybe true in turbulence, but at different altitudes (DA), different weights, etc the optimum pitch attitude is going to vary. You would have to establish pitch using airspeed and then maintain whatever pitch that happens to be, not just use 3º every time.

POH speed is for maximum gross weight, unless it's given for multiple weights. You can calculate the adjusted-for-weight version of most airspeeds by multiplying by the square root of the quotient of actual weight vs max gross. IE, 3600 pound max airplane being flown at 3000 pounds, sqrt(30/36) * Vwhatever.


There is an optimum angle while you're still on the water, but you're correct that once in the air, it's just an AIRplane. The floaty ones just have a bunch of extra weight and drag on 'em.

On the water, you start with full aft stick, full power, and it'll pitch up at which point you let the nose back down. Now you're on the step. While there, if your pitch is too low you won't be developing enough lift and thus the floats will have to displace more water to hold you up and you'll never get to takeoff speed. If your pitch is too high you've got too much aero drag and might be putting the back end of the floats back into the water again, which again means more drag and you'll never get to takeoff speed. Gotta keep it just right, right in the middle. And if you're flying something less overpowered than a C185, if you don't do it right you'll just have a very expensive boat. Even a Super Cub will just barely get off the water (well, when it's carrying ME anyway :rofl:). You can "encourage" it with a quick tug when you're close to the max speed you'll get on the water and that might give you enough of a bump in lift to get the floats out of the water, which removes a TON of drag and lets you start flying, kinda. You're still in "water effect" and need to stay there for a few seconds just like on a soft field takeoff. You can feel the drag going away, though, because as soon as you're out of the water it'll surge forward. Fun stuff!
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I fly a rather large plane, we more or less fly the FD which is showing pitch based on many variables, outside of the school house steep turns and the like, or flight with airspeed unknown QRH, we don’t have fixed pitch settings really

Seaplane world you can feel the sweet spot on step, if you’re eyes inside on the water, you ain’t seaplanin’ right
 
Roller said:
I fly a rather large plane, we more or less fly the FD which is showing pitch based on many variables, outside of the school house steep turns and the like, or flight with airspeed unknown QRH, we don’t have fixed pitch settings really
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But the FD is giving pitch based on... What? Hit the TOGA and it sets takeoff pitch, and after the initial climb is established, FLC which is airspeed. Airspeed takes care of the variables.

But in any case, it's not "three degrees". Heck, I think the Mooney does better than that in a cruise climb.
Roller said:
Seaplane world you can feel the sweet spot on step, if you’re eyes inside on the water, you ain’t seaplanin’ right
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After all that writing I did, I failed to mention that I have no idea what that sweet spot pitch is. I don't think I've ever flown a seaplane with an AI, and even if I did, it's not like I'd be checking my AI during takeoff. It's all feel and outside view.
 
flyingcheesehead said:
But the FD is giving pitch based on... What? Hit the TOGA and it sets takeoff pitch, and after the initial climb is established, FLC which is airspeed. Airspeed takes care of the variables.

But in any case, it's not "three degrees". Heck, I think the Mooney does better than that in a cruise climb.

After all that writing I did, I failed to mention that I have no idea what that sweet spot pitch is. I don't think I've ever flown a seaplane with an AI, and even if I did, it's not like I'd be checking my AI during takeoff. It's all feel and outside view.
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Initially yeah it’s a pitch, but shortly after breaking ground it’s going to a VNAV mode


Ether way, holding X degrees pitch for the initial climb in a 100-200 series Cessna on floats ain’t the way to do it
 
flyingcheesehead said:
Really?? That doesn't make sense to me. Once established in the climb (ie, no vertical acceleration), the weight of the aircraft is the same in both cases and for the climb to remain vertically unaccelerated you need lift to equal weight, thus you need equal lift for both Vx and Vy. Since Vx is slower, your AoA needs to be higher to develop the same lift.
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Poorly worded on my my part wasn't saying Vx and Vy have the same angle of attack. Was was saying that Vx AOA is always about the same and Vy AOA is always about the same.
Brian
 
brcase said:
Poorly worded on my my part wasn't saying Vx and Vy have the same angle of attack. Was was saying that Vx AOA is always about the same and Vy AOA is always about the same.
Brian
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Is this true at all take-off weights? Intuitively wouldn’t think so, but I can’t say that I’ve really paid attention to deck angle, other than focusing on flying Vy speeds within the allowable weight envelope when maxed out.

And density altitudes? Based on experience, my deck angle is ridiculous in the winter vs the same Vx in summer. And the Vy climb out west is pathetically flat vs home in the Midwest.
 
Never flown or seen a seaplane with a real full flying AOA
 
455 Bravo Uniform said:
Is this true at all take-off weights? Intuitively wouldn’t think so, but I can’t say that I’ve really paid attention to deck angle, other than focusing on flying Vy speeds within the allowable weight envelope when maxed out.

And density altitudes? Based on experience, my deck angle is ridiculous in the winter vs the same Vx in summer. And the Vy climb out west is pathetically flat vs home in the Midwest.
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The thing to remember is AOA isn't the same as Attitude. As the performance difference widens so does the difference between AOA and attitude. Attitude is pretty good for consistent climbs a given or narrow range of weights and power, but starts to fall apart as the weights and power settings ranges widen.
For example just picking a AOA number lets say your best Vx AOA is 10 degrees. Heavy on a hot summer day your climb angle might only be 2 degrees the AOA is still10 to the relative wind of 2degrees so your attitude is 12 degrees up.
For a Light on a cold day your climb angle might be 7 degrees, AOA is still 10 degree, so Attitude is 17 degrees.

Brian
 
brcase said:
The thing to remember is AOA isn't the same as Attitude. As the performance difference widens so does the difference between AOA and attitude. Attitude is pretty good for consistent climbs a given or narrow range of weights and power, but starts to fall apart as the weights and power settings ranges widen.
For example just picking a AOA number lets say your best Vx AOA is 10 degrees. Heavy on a hot summer day your climb angle might only be 2 degrees the AOA is still10 to the relative wind of 2degrees so your attitude is 12 degrees up.
For a Light on a cold day your climb angle might be 7 degrees, AOA is still 10 degree, so Attitude is 17 degrees.

Brian
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How are you defining “climb angle”?
 
brcase said:
Poorly worded on my my part wasn't saying Vx and Vy have the same angle of attack. Was was saying that Vx AOA is always about the same and Vy AOA is always about the same.
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Ooooooohhhhh, gotcha.
brcase said:
The thing to remember is AOA isn't the same as Attitude. As the performance difference widens so does the difference between AOA and attitude. Attitude is pretty good for consistent climbs a given or narrow range of weights and power, but starts to fall apart as the weights and power settings ranges widen.
For example just picking a AOA number lets say your best Vx AOA is 10 degrees. Heavy on a hot summer day your climb angle might only be 2 degrees the AOA is still10 to the relative wind of 2degrees so your attitude is 12 degrees up.
For a Light on a cold day your climb angle might be 7 degrees, AOA is still 10 degree, so Attitude is 17 degrees.
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It's important to keep in mind here that Vx and Vy are not constant, they vary with weight. @455 Bravo Uniform that's probably why it doesn't make intuitive sense at first. Also, make sure like @brcase says that you're not confusing your pitch/deck angle with AoA.

Like most V speeds, they vary with weight, specifically by the square root of the ratio of the weights in calibrated airspeed.

So, if Vx at 3000 pounds is 70 knots CAS, Vx at 2500 pounds is 64 knots CAS. (sqrt(2500/3000)*70) Same with Vy. Thus, when you're lighter, you should also be slightly slower, leading to an even greater difference in attitude/deck angle.
Salty said:
How are you defining “climb angle”?
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I am not @brcase but given what he typed there, it should be the angle between the ground and the aircraft's path.
 
flyingcheesehead said:
I am not @brcase but given what he typed there, it should be the angle between the ground and the aircraft's path.
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That does not seem to be the case as temperature would not affect that angle unless you were trying to meet some other criteria.
 
Salty said:
That does not seem to be the case as temperature would not affect that angle unless you were trying to meet some other criteria.
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What? Sure it would. Cold (low DA) gives you a much higher path over the ground than hot (high DA)...
 
Temperature makes you pull on the elevator harder? How does it do that?
 
Re-reading his post, I think he’s saying a Vx climb. I didn’t catch that first read. So the answer to my question is Vx climb angle.
 
Thanks everyone for the discussion here. While I might have been simplifying things across all of aviation based on my experience flying ASEL, it would seem SGOTI did it worse. LOL.

I learned a little here, so props to adding some content into the training forum.
 
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