Slow or fast climb...what's quicker?

jfrye01

jfrye01

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Jacob Frye
Hello..I have a question that has been bothering me for as long as I have been doing cross country flights...is it faster to climb up to cruising altitude at a higher climb rate, or is it faster to to slowly climb out at a higher airspeed? Does it make much difference? Obviously when leveled off you cruise faster, so I'm having some trouble figuring it out. Forgive me if this is a stupid question:p
Thanks!
 
Best angle will get you to altitude faster over the ground but not necessarily in the fastest time. Best rate will get you to altitude in the least amount of time but not necessarily the shortest distance.

Any speed faster than best rate of climb will take you longer to get to cruise altitude.

There are many reasons to use a climb speed faster than best rate of climb speed. One is for engine cooling and another is for visibility over the nose.
 
jfrye01 said:
Hello..I have a question that has been bothering me for as long as I have been doing cross country flights...is it faster to climb up to cruising altitude at a higher climb rate, or is it faster to to slowly climb out at a higher airspeed? Does it make much difference? Obviously when leveled off you cruise faster, so I'm having some trouble figuring it out. Forgive me if this is a stupid question:p
Thanks!
Click to expand...

Are you familiar with Vx and Vy? Vx will give you the best climb for the smallest distance covered (think trying to get over large trees on departure) while Vy will give you the best climb for the smallest time (which, I think, is what you're asking about). Look in the aircraft POH to determine airspeeds for each.

Theres's a good image at this link that illustrates the two: http://flighttraining.aopa.org/magazine/2013/February/feature-vx-vs-vy.html
 
Not a stupid question at all.

If you regularly fly the same airplane, experiment!

Climb out at different speed/climb rates, and record the results. Keep an eye on engine temps, too.
 
Good question and a very complicated topic.

I recall in air races, pilots would often barely, barely climb, so as to reach their optimum altitude at the midpoint, then barely, barely descend to the destination/finish line. Point being that lower speeds in even a short, steep climb were difficult to recover.

But there are just SO many variables:

Performance at altitude
Winds at altitude
Engine cooling
Fuel consumption in the climb vs. cruise
Oxygen requirements
Time spent at lower altitudes with fewer landing options and/or rougher air
Cloud layers
Airspace restrictions
...and many, many more.

Most POH's will list a "Cruise Climb" which is not a bad starting point. Plus flight planning software will make plugging in lots of "what if scenarios" relatively painless.
 
Yep, you'll keep on going over this question as long as you fly. There are many variables some days a lazy high airspeed climb then long shallow descent will be best due to headwinds, or even be required because someone can't clear their ears. Some days it may pay to climb Vy all the way to altitude and keep it there due to favorable winds aloft. Then there are operating temp issues to consider as well.
 
In terms of total flight time, it's hard to say -- you'd have to run the numbers using your POH performance data with regard to varying winds as you climb. As Henning said, it's an issue for air racers where 30 seconds can make a difference, but personally, it's not something I worry about -- as Greg said, I'm more concerned with engine cooling than saving one or two minutes over a flight of a couple of hours. For that reason, unless I have obstruction issues, I use Vy to 400 AGL, then cruise climb from there to cruising altitude, and the flight takes as long as it takes.
 
in the average light GA ac you will never be able to tell in the real world.

This is because you will never really approach the destination airport the same way twice. Even if you are going to a non-towered pilot controlled field with 2 operations a day changing your over the ground distance even 500 yards skews the numbers. Add into that a 2 mph speed difference because the airplane is clean, or dirty, or its 5 degree cooler - you'll never see it in the real world. . . and it will not matter since it takes as long as it takes to get from point a to point b.


You are welcome to do the still air math- and it will come out to less than 2 min either way - and thats lost or gained by the smallest of things . . .
 
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Ron Levy said:
unless I have obstruction issues, I use Vy to 400 AGL, then cruise climb from there to cruising altitude, and the flight takes as long as it takes.
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:yeahthat:
 
The easy answer is: It depends.:D
I normally use a cruise climb in the 182 of around 100 knots, certainly not best angle or best rate, but it's comfortable for passengers, visibility is good, cooling is good and it gives me 5-600 FPM and keeps ATC happy. If I am trying to get above or through clouds I may pull it back to 85-90 knots and try to get up a little quicker.
I think you'll find that it's more a matter of personal choice and it rarely makes much difference in trip times. Saving 2 minutes on a 45 minute trip isn't going to change your life. :D
 
depends on if you're climbing into a headwind or a tailwind. there is probably an optimum speed based on the wind profile for the flight.

i'd recommend you put as much weight as possible/available in the furthest aft baggage area. if it is a convective day try to find a cloud street otherwise seek smooth air. turbulence really slows you down if you insist on holding altitude.
 
There's another factor for some aircraft as well. On my Archer if I climb out at Vy my nose blocks the view straight ahead of me.
 
Of course there are a lot of other variables. But, assuming no wind, and all other things being the same or neutral, then it really depends on your cruise power vs your climb power.

If your cruise power is dialed back lower than climb, then the longer you take to climb, you will get there faster simply because you would be using a higher power level for a longer period of time.

But, if you increase your power in cruise relative to climb, then the faster you get to cruise altitude, the quicker you will get there, because you would then be using the higher cruise power level for a longer period.
 
skidoo said:
Of course there are a lot of other variables. But, assuming no wind, and all other things being the same or neutral, then it really depends on your cruise power vs your climb power.

If your cruise power is dialed back lower than climb, then the longer you take to climb, you will get there faster simply because you would be using a higher power level for a longer period of time.

But, if you increase your power in cruise relative to climb, then the faster you get to cruise altitude, the quicker you will get there, because you would then be using the higher cruise power level for a longer period.
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And here I thought climb power is full power. That's how I climb, anyway. Cruise power is altitude dependent to a larger degree.
 
Hank S said:
And here I thought climb power is full power. That's how I climb, anyway. Cruise power is altitude dependent to a larger degree.
Click to expand...

Some airplanes have time limits at full power, and the limit may be less than it takes to climb to cruise altitude.
 
I watch the temps. Vy all the way up, unless I want to see over the nose or the temps start going up, then a cruise climb that holds 500ft/min - also double check the temps..
 
jfrye01 said:
Hello..I have a question that has been bothering me for as long as I have been doing cross country flights...is it faster to climb up to cruising altitude at a higher climb rate, or is it faster to to slowly climb out at a higher airspeed? Does it make much difference? Obviously when leveled off you cruise faster, so I'm having some trouble figuring it out. Forgive me if this is a stupid question:p
Thanks!
Click to expand...

You can try to hold a constant vertical speed, but eventually you will have to trade that climb rate for airspeed as the engine starts producing less power as it climbs. Which is why in a small single engine plane you climb at an airspeed and not a vertical speed.

The quickest way to your cruising altitude? Fly Vy
If you want to get to your cruising altitude over the shortest amount of ground distnace? Fly at Vx

It didn't make sense for awhile for me but you have to think of them on a line graph. Vy is a relationship between altitude and time, while Vx is a relationship between altitude and distance. As Samuel L. Jackson says, "It ain't the same ballpark...Ain't even the same freakin sport!"

If two identical planes took off at the exact same time and one flew at Vy and the other at Vx:

Vx plane will be higher than the Vy plane for a bit...but after a bit of time, Vy would close the altitude gap and be higher than Vx and be further from the departure airport.

Picture two planes flying at different angles, and the plane at the steeper angle is flying slower than the one at the shallower angle.
 
jfrye01 said:
Hello..I have a question that has been bothering me for as long as I have been doing cross country flights...is it faster to climb up to cruising altitude at a higher climb rate, or is it faster to to slowly climb out at a higher airspeed? Does it make much difference? Obviously when leveled off you cruise faster, so I'm having some trouble figuring it out. Forgive me if this is a stupid question:p
Thanks!
Click to expand...

Depends on terrain. If terrain is no issue, climb slower at 90%. If terrain is an issue, climb at bigger angle at full throttle.
 
One reason I prefer higher speed, shallower climb:

The airplane I normally fly will climb like a rocket at 65 knots, yet I usually climb at 120 knots.

At 65 knots, if the engine lost power, I have very little time to shove the nose down to avoid a stall.

At 120 knots, I can be befuddled for a second or two, wondering "what's happening?" and still have time to regain the thought process and fly the airplane to best glide.

Bottom line, lots of safety margin, acknowledging that I'm human, and not likely to perform at peak effectiveness during an emergency.
 
Greg Bockelman said:
Best angle will get you to altitude faster over the ground but not necessarily in the fastest time. Best rate will get you to altitude in the least amount of time but not necessarily the shortest distance.

Any speed faster than best rate of climb will take you longer to get to cruise altitude.

There are many reasons to use a climb speed faster than best rate of climb speed. One is for engine cooling and another is for visibility over the nose.
Click to expand...

Greg, and your CFI, sure got that right; especially near an airport - towered or not.
 
Non Compos Mentis said:
At 65 knots, if the engine lost power, I have very little time to shove the nose down to avoid a stall.
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Unless I'm misunderstanding the aerodynamics:

You're trimmed for 65 kts, so if you lose power the nose should come down of its own accord and the plane will descend at 65 kts. Should be no need to shove anything forward except mixture or whatever else might revive the engine.

If anything, you may need to pull back a bit more to slow to best glide because climb speed trim is probably a higher speed.

Perhaps what some pilots do wrong that puts them into a stall after engine out is trying to maintain aircraft attitude?
 
CTLSi said:
If terrain is no issue, climb slower at 90%.
Click to expand...

Word of caution...

Some engines have enrichening circuits that come into play at full throttle. So with those engines, throttling back even a little may put the mixture in a bad spot.

As always, best to follow POH recommendations.

Edited to add: this may not apply to your fuel injected ROTAX. Still, following the book is still a good idea. Pulling back to 90% for the climb may not really have any benefit.
 
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the airlines are continuously trying to come up with flight profiles that answer this question.

It's a complicated question.
 
Hank S said:
And here I thought climb power is full power. That's how I climb, anyway. Cruise power is altitude dependent to a larger degree.
Click to expand...

For your airplane, maybe so... But, not all... For example, in mine, full power climb is 32", 24 gph. But, a normal climb is 25" and 16 gph. Full power is used for takeoff, and I typically dial it back to normal climb power for the duration of climb to save stress and fuel. Once at cruise, I have the option to increase power to as much as 27 to 28" if desired. But, I usually keep it under 25" anyway...
 
jfrye01 said:
Hello..I have a question that has been bothering me for as long as I have been doing cross country flights...is it faster to climb up to cruising altitude at a higher climb rate, or is it faster to to slowly climb out at a higher airspeed? Does it make much difference? Obviously when leveled off you cruise faster, so I'm having some trouble figuring it out. Forgive me if this is a stupid question:p
Thanks!
Click to expand...
If I understand your question correctly there are a lot of answers to something other than what you asked in this post. As far as I can tell, Skidoo was the only one who came close to answering the question you asked which I think is "Will a cross country trip take less total time if I climb to my cruising altitude with a higher rate of climb?".

And like Skidoo said, if you ignore things like wind changing with altitude and assume you're climbing at a higher power level than what you use for cruising the slower your climb rate the less time the trip will take.

I suspect that the reason most of the replies in this thread were about Vy, Vx, and other things besides the answer to your question is that the question itself is somewhat flawed. If your primary goal is to minimize the time required for the flight, baring a significantly stronger headwind component down low, you would be better off flying at the lowest safe altitude possible while running maximum power the whole time.

But that completely ignores something that most pilots (some rental pilots excluded) consider at least as important as "getting there fast" i.e. fuel economy.
 
Simpliatic view: 1/3 on the way up- 1/3 the way there- 1/3 the way down

Adjust from there
 
Jim Logajan said:
Unless I'm misunderstanding the aerodynamics:

You're trimmed for 65 kts, so if you lose power the nose should come down of its own accord and the plane will descend at 65 kts. Should be no need to shove anything forward except mixture or whatever else might revive the engine.

If anything, you may need to pull back a bit more to slow to best glide because climb speed trim is probably a higher speed.

Perhaps what some pilots do wrong that puts them into a stall after engine out is trying to maintain aircraft attitude?
Click to expand...

Good thought process.

Full-power climb at 65 knots is an extremely nose-high attitude, not far from stall speed. Best glide in this airplane is way higher than 65.

Just an example of how important it is to know the unique characteristics of the particular airplane one flies.
 
Ah Gismo cleared that up a little. In a small airplane that you usually fly in the 3,000 - 7,000 foot range, I usually do a "cruise climb" of something greater than Vy. I'm usually renting the plane, not flying more than 3 hours away, so I am not trying to get to altitude in a hurry to conserve fuel and attain a higher true airspeed or a greater tailwind. I'm looking for what will give me the lowest flight time. Probably a more important question would be what altitude to fly at.

Will I benefit from the extra knots of true airspeed, lower fuel burn, and better tailwind at a higher altitude and sacrifice being at a slower climb airspeed for an extra 5-10 minutes? Or stay down low and fly at a lower true, but higher groundspeed cause of less headwind?

Lot of factors you have to personally think about based on a lot of different factors.
 
I attended a seminar by Norman Howell at Oshkosh this year discussing this topic. He had a very detailed and methodical look at the problem and came up with a new V-speed - Vz.

Complete explanation: http://www.seqair.com/benchmark/Howell/Norman.html

Basically, you climb at 1.32 x Vy(at SL) until your climb rate decreases to 500 fpm. Then you hold 500fpm until your speed hits Vy, then you climb at Vy.

He has a 97-page masters thesis explaining why this is more efficient/better. The goal was "speed with economy".
 
dans2992 said:
I attended a seminar by Norman Howell at Oshkosh this year discussing this topic. He had a very detailed and methodical look at the problem and came up with a new V-speed - Vz.

Complete explanation: http://www.seqair.com/benchmark/Howell/Norman.html

Basically, you climb at 1.32 x Vy(at SL) until your climb rate decreases to 500 fpm. Then you hold 500fpm until your speed hits Vy, then you climb at Vy.

He has a 97-page masters thesis explaining why this is more efficient/better. The goal was "speed with economy".
Click to expand...

Interesting, and I guess that cruise altitude is irrelevant, you fly the same performance profile and just interrupt it whenever you hit cruise altitude.
 
Very interesting. I'll have to read that tonight
 
cowman said:
There's another factor for some aircraft as well. On my Archer if I climb out at Vy my nose blocks the view straight ahead of me.
Click to expand...

But you are doing climbing. You don't need to see straight ahead. :lol:

;)


Good question OP!
 
CTLSi said:
Depends on terrain. If terrain is no issue, climb slower at 90%. If terrain is an issue, climb at bigger angle at full throttle.
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If you mean throttle back to 90% power, you risk cooking your cylinders in some engines. Your cooling system is designed to work best at about 75% power and cruise speed. In order to handle the extra heat of full throttle at the lower speeds of climb, the carburetor system is designed to create and extra-rich mixture at full throttle. You can see this by setting full throttle, noting your EGT's and CHT's, then pulling the throttle half an inch off the full-throttle stop without changing speed -- EGT and CHT will both rise. So, unless your POH calls for partial power climbs, leave the throttle at full open for climbs unless you have the engine instrumentation to monitor CHT on all cylinders and are prepared to lower the nose for extra speed at the expense of significantly reduced climb rate to keep the CHT's where you want them.
 
dans2992 said:
I attended a seminar by Norman Howell at Oshkosh this year discussing this topic. He had a very detailed and methodical look at the problem and came up with a new V-speed - Vz.

Complete explanation: http://www.seqair.com/benchmark/Howell/Norman.html

Basically, you climb at 1.32 x Vy(at SL) until your climb rate decreases to 500 fpm. Then you hold 500fpm until your speed hits Vy, then you climb at Vy.

He has a 97-page masters thesis explaining why this is more efficient/better. The goal was "speed with economy".
Click to expand...
I don't know about your plane, but trying to climb my 90 KIAS Vy Tiger at 1.32Vy (119 KIAS) would result in a very low climb rate (not sure I'd ever see 500 fpm), and probably overspeeding the engine past the RPM redline. I'll stick with the recommended Vy+10 for cruise climb, as that gives me a goo climb to cruise altitude while keeping CHT's where I want them in climb.
 
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I'm sure piston are different, but I remember being surprised when flying a Citation 500 that you could point the nose up and get XXX fpm climb at say 140 kias or you could put the nose down and get the same XXX fpm climb at 200 kias. The faster you go the more lift you get over the wing. You got down the road faster even though you didn't climb to altitude in as short a distance. We used to keep the climb shallower and let 'er rip.
 
I was flying our Citation out of Opa Locka one day and the departure called for 250 knot airspeed!:eek: I wasn't sure it would climb at 250! But, IIRC I got 12-1500 FPM! :D
jnmeade said:
I'm sure piston are different, but I remember being surprised when flying a Citation 500 that you could point the nose up and get XXX fpm climb at say 140 kias or you could put the nose down and get the same XXX fpm climb at 200 kias. The faster you go the more lift you get over the wing. You got down the road faster even though you didn't climb to altitude in as short a distance. We used to keep the climb shallower and let 'er rip.
Click to expand...
 
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