Flying with a pulse - oximeter

[gbigs]

So if I quickly climbed up well above 14k and then descended back down I would die?

Read it again, I did not say descend..

 

The 100's of plane loads of jumpers (along with the pilots) that used to jump out of my local airport at 17,500 must have all died, no wonder that place is closed down now. It makes sense now thanks for clearing that up.

Again, no one said descend.

 

 

We have lots of mountains above 14k here in Colorado, so technically a sport pilot could need or want to go that high and still remain within 2,000 agl and not break one of the silliest rules ever created.

The CT according to the POH  cannot fly that high safely since the climb rate drops to zero.  May want to reread the limits.

 

 

I agree that depending on where you live, and what you are acclimated to, and your health and fitness all play into what kind of altitude you can safely fly (not talking about the rules, talking about what's actually real)... but you did state that LSA's can't go above 14k, and that is not accurate. Sorry... you said it.

No. I said the ceiling and altitude at which climb drops to ZERO according to the POH are 12,300 and 13,400.  I also said any aircraft can be pushed higher by thermals and mountain wave which is life-threatening if you don't have oxygen on board and know how to use it.

[FlyingMonkey]

 

 

We have lots of mountains above 14k here in Colorado, so technically a sport pilot could need or want to go that high and still remain within 2,000 agl and not break one of the silliest rules ever created.

The CT according to the POH  cannot fly that high safely since the climb rate drops to zero.  May want to reread the limits.

 

 

I agree that depending on where you live, and what you are acclimated to, and your health and fitness all play into what kind of altitude you can safely fly (not talking about the rules, talking about what's actually real)... but you did state that LSA's can't go above 14k, and that is not accurate. Sorry... you said it.

No. I said the ceiling and altitude at which climb drops to ZERO according to the POH are 12,300 and 13,400.  I also said any aircraft can be pushed higher by thermals and mountain wave which is life-threatening if you don't have oxygen on board and know how to use it.

 

 

 

You might need to brush up on the definition of service ceiling.  It's the point at which climb rate in the clean/cruise configuration drops to 100fpm or less, not zero.  Add flaps in and you can continue climbing.  

 

A CT is not limited to 13,400ft by anything other than a POH suggestion.

[FastEddieB]

You might need to brush up on the definition of service ceiling. It's the point at which climb rate in the clean/cruise configuration drops to 100fpm or less, not zero. Add flaps in and you can continue climbing.

 

 

To reiterate, it's also at max gross with forwardmost CG under standard conditions.

 

Less than gross, not at the forward limit or cooler/denser than standard and up you go!

 

But flaps sound dubious. Has that been documented? Never heard of that helping.

[Ed Cesnalis]

Some flaps help, not all flaps.

 

If I need to clear terrain above 10,000' and the performance isn't there I could turn away and climb then back on course or I could simply use more flaps.  Its my habit to climb with reflex flaps.  When I need more there is generally 2 more settings available.

 

• -6/-12 increased to zero  - enhances climb whenever IAS < 100kts.
• 0 increased to 15  - climb angle maximizes
• 15 inreaded to 30 - climb reduces
• 30 increased to 40 - what climb?

[FlyingMonkey]

We get better climb on takeoff with 15 flaps than with 0, and much more than with -6.  Why would that not hold true just because the ground isn't nearby?

[FastEddieB]

We get better climb on takeoff with 15 flaps than with 0, and much more than with -6.  Why would that not hold true just because the ground isn't nearby?

While I'm pondering that, anyone care to venture why forward cg is specified when calculating ceilings?

[FastEddieB]

Here you go:

 

"Flaps and landing gear

 

Extending the flaps will decrease the climb performance as L/D ratio is reduced and the power required increased. The best rate-of-climb and angle-of-climb is always reached with flaps up. Hence the need to retract flaps after a go-around if there are obstacles in the climb out path. Some aircraft are not able to climb if full flaps are selected due to the amount of drag they create. For example: a C-172 with full flaps does not climb like a homesick angel during a full power go-around.

 

Some aircraft manufacturers recommend a take-off setting for flaps during a short field or high performance take-off. Although L/D ratio will suffer and drag is increased by the flaps it will permit the aircraft to fly off the runway sooner, but the climb out performance will be somewhat less."

 

Source: http://www.experimentalaircraft.info/flight-planning/aircraft-climb-performance.php

[Ed Cesnalis]

Here you go:

 

"Flaps and landing gear

 

Extending the flaps will decrease the climb performance as L/D ratio is reduced and the power required increased. The best rate-of-climb and angle-of-climb is always reached with flaps up. Hence the need to retract flaps after a go-around if there are obstacles in the climb out path. Some aircraft are not able to climb if full flaps are selected due to the amount of drag they create. For example: a C-172 with full flaps does not climb like a homesick angel during a full power go-around.

 

Some aircraft manufacturers recommend a take-off setting for flaps during a short field or high performance take-off. Although L/D ratio will suffer and drag is increased by the flaps it will permit the aircraft to fly off the runway sooner, but the climb out performance will be somewhat less."

 

Source: http://www.experimentalaircraft.info/flight-planning/aircraft-climb-performance.php

 

'drivel' synonyms: nonsense, twaddle, claptrap, balderdash, gibberish, rubbish, mumbo jumbo, garbage

 

Extending the flaps will decrease the climb performance as L/D ratio is reduced except when it doesn't as L/D ratio is increased. 

 

A CT with 15* takeoff/climb flaps does climb like a homesick angel.  

 

Hint:

• When you extend to 0* or extend to 15* the Lift will increase more than the drag, does that increase or decrase the L/D?
• When you extend to 30* or extend to 40* the Lift will increase less than the drag, does that increase or decrase the L/D?
• Using presets there are 4 flap extensions available. Do all 4 reduce the L/D?  If not how could the article be correct?

[FastEddieB]

Basically, increasing lift causes a plane to accelerate upwards, not to climb at a higher overall rate.

 

In a steady state climb, lift=weight. In general, flaps increase drag, which hurts in the climb.

 

There's a reason why Vy is given clean. In general, any flaps will hurt that rate.

 

In both cases, I said "in general" because there are some fancy flap types out there that may be exception.

 

As an aside, to date I've never heard of a plane with a higher ceiling specified for partial flaps. I'm perfectly willing to be shown such and adjust my thinking.

 

Further food for thought here: http://www.flyingmag.com/can-flap-deflection-help-you-climb

[Ed Cesnalis]

... accelerate upwards, not to climb at a higher overall rate.

 

In a steady state climb, lift=weight. In general, flaps increase drag, which hurts in the climb.

 

 

 

accelerate upwards, not to climb at a higher overall rate.   -  Don't these two things mean exactly the same thing?

 

In a steady state climb, lift=weight  -  In level cruise lift=weight, in climb lift>weight resulting in climb.

 

flaps increase drag, which hurts in the climb.  That's like saying RPM determines power. There are 2 factors RPM and MP and their result has to increase to increase power. In the case of climb the result of lift dived by drag determines the climb.  When you say flaps increases drag which hurts the climb I say flaps increases lift which aids the climb, which one is greater?

[FastEddieB]

accelerate upwards, not to climb at a higher overall rate. - Don't these two things mean exactly the same thing?

 

No.

 

A plane climbing at 500 fpm is not accelerating upwards.

 

A plane increasing it's rate of climb from 500 fpm to 1,000 fpm is, but only until it stabilizes at the new rate.

 

 

In a steady state climb, lift=weight - In level cruise lift=weight, in climb lift>weight resulting in climb.

 

Airplanes climb due to excess thrust, not lift greater than weight:

 

 

 

flaps increase drag, which hurts in the climb. That's like saying RPM determines power. There are 2 factors RPM and MP and their result has to increase to increase power. In the case of climb the result of lift dived by drag determines the climb. When you say flaps increases drag which hurts the climb I say flaps increases lift which aids the climb, which one is greater?

 

Pretty sure you're wrong on this.

 

Best rate will be found without flaps, with perhaps some rare exceptions.

 

I have yet to see a plane that did not call for flaps to be retracted once obstacles were cleared. If planes climbed better with flaps, why not just leave them down? If they worked so well, engineers could certainly manage a higher Vfe. Some planes call for flaps because the shorter ground run results in a net plus to get over an obstacle, not because the plane climbs at a better rate or angle once airborne - again stipulating there may be exceptions.

[FlyingMonkey]

Basically, increasing lift causes a plane to accelerate upwards, not to climb at a higher overall rate.

 

In a steady state climb, lift=weight. In general, flaps increase drag, which hurts in the climb.

 

 

Isn't that ONLY true insofar as the additional drag penalty is greater that the increased lift gained from the flaps?

 

If we take two airplanes of the same weight and power, one with very small, low lift wings, and the other with large, high-lift wings, don't we expect the one with more wing (e.g. more lift) to climb better in general?  Excess power is part of the climb equation, but surely it doesn't end there.  If it did, an airplane with tiny stub wings barely able to support its weight in level flight, would outclimb one with larger wings, in all cases, if it had only 1% more power!

 

I think excess power being the sole determinant of climb works well for a single configuration.  For example, a CT at -6 flaps at 5200rpm making say 80hp, will not climb as well as a CT at -6° at 5500rpm making 95hp.  But when you go to flaps 0° you have changed the wing and lift coefficient, and the two are no longer directly comparable based purely on power.  

 

The 0° plane is making more lift on the same power as the -6° plane, but is also incurring an additional drag penalty.  If the upward force of the additional lift exceeds the retarding force of the excess drag at the climb angle of attack, the 0° flaps plane WILL climb faster.  If not, then it will climb slower.

 

Gliders have zero excess power, yet they climb...how is that? 

 

This is how I see things, does it make any sense?

[FlyingMonkey]

Also, doesn't excess power simply generate more speed to generate more lift from the wing, or is it your contention that the propeller does the work in a climb?  The faster a wing moves through the air, the more lift it generates which by AoA is converted to a climbing force.  Propeller thrust may have some effect "pulling" the airplane up at very high AoA, but in general it's providing thrust and not lift.  

 

I don't think most airplanes climb based on thrust.  If they did, why have wings at all?  

 

Again...as I see it.  

[Roger Lee]

Hi Eddie,

 

Your thought would be true with too much flap, but not 10-15.

 

A CT gains more altitude off a 3k ft. runway and within that 3k ft. with 15 flaps verses zero flaps. As you gain very high altitudes you may loose climb in -6 flaps, but dropping to zero flaps regains your climb. It's the only way I take off because I'm usually heavier than the other CT. I always out climb a CT in that 3k ft. over the zero flap guy. I'm also off the ground sooner. When we are at the Page FlyIn and density altitudes at 9500+ I would have a hard time getting off the ground without 15 flaps. I want to be as high as possible by the time I run out of runway or just past it. Zero flaps doesn't get me there.

 

With all the other LSA I get to fly that pretty much holds true for them too.

[FastEddieB]

Lots of misunderstanding about what makes an airplane climb, and the effect of flaps on performance.

 

A bit of that misunderstanding has been shown here.

 

Rather than reinvent the wheel, let me recommend...

 

"Aerodynamics For Naval Aviators"

 

"Pilot's Handbook of Aeronautical Knowledge"

 

Both available online for free.

 

I'll address individual points going forward, but those books cover the topic pretty well.

[Ed Cesnalis]

 

Airplanes climb due to excess thrust, not lift greater than weight:

 

...

 

Pretty sure you're wrong on this.

 

Best rate will be found without flaps, with perhaps some rare exceptions.

 

 

On acceleration, I agree, originally I mistook your meaning.

 

 

Airplanes climb due to excess thrust, not lift greater than weight:   -   A jet fighter in a vertical climb demonstrates this.  How it applies to climbing in a CT I can't see.

 

When flying the Europa we sometimes turn the engine off and feather the prop.  In this configuration sometimes we climb.  With no thrust I'm guessing its the wings providing the excess lift resulting in climb?

 

The reason that I'm confident that 15* will give me 'better' climb is I've used this countless times to climb over terrain that I was unable to out climb with cruise flaps.  In this case its a better angel that's needed not a better rate.

[Roger Lee]

Two trains of thought or theories Eddie.

Old school is lift to drag only. Second thought is angle of attack and forward wind forces pushing the wing upward. Just like when you put your hand out the wind and the wind force pushes your hand up.

 

I believe both theories are at work. The second helps explain why a little flap works.

Plus we have real world experience to prove our postition and not just a theory. Hard to hold a two sided debate when one side does it on a daily basis.

 

I know you have some CT's in your area. Go try a zero flap takeoff and a 15 flap one. At the end of the runway report back which got you higher in that distance or even 300-400 yards farther out.

[Ed Cesnalis]

Two trains of thought or theories Eddie.

Old school is lift to drag only. Second thought is angle of attack and forward wind forces pushing the wing upward. Just like when you put your hand out the wind and the wind force pushes your hand up.

 

 

 

Roger,

 

You are just describing a type of lift called 'impact lift'.  The discussion at hand is now where excess lift that results in climb comes from.  I'm saying it comes from the wing including impact lift that you describe where Eddie says it comes from the prop.

[Ed Cesnalis]

Lots of misunderstanding about what makes an airplane climb, and the effect of flaps on performance.

 

A bit of that misunderstanding has been shown here.

 

Rather than reinvent the wheel, let me recommend...

 

"Aerodynamics For Naval Aviators"

 

"Pilot's Handbook of Aeronautical Knowledge"

 

Both available online for free.

 

I'll address individual points going forward, but those books cover the topic pretty well.

 

 

Okay, I'm calling you out Fast Eddie, that kind of behavior won't fly around here.!

 

You basiclly restated your rather dubious position and told the rest of us to study up, kinda like so that we can get to your level and even have a discussion.

 

In stead of giving me books to read I want to hear, in a persuasive way, how my CT at 13,500' can be climbing due to the 49hp  (less at the prop) as opposed to due to the lift provided by the wings.  This just isn't passing the smell test, say it so I believe it!

[gbigs]

Normally a glider is always descending from their towed-to altitude at a slow rate due to efficiency.    A glider can gain altitude by increasing its potential energy using updrafts (thermals, ridge lift and wave lift).  To gain altitude a glider may need to circle inside an updraft that has enough force to overcome it's weight. 
 

Small planes are in danger over mountains given such ridge and wave updrafts are easily strong enough to lift the plane to unwanted higher altitudes and even overpower attempts to exit the updraft in order to reduce altitude. 

 

The gliders I have seen have oxygen.  Not all small planes have oxygen making mountain flying much more hazardous for them even beyond the non-turbo, underpowered engines that may not lift them high enough to clear the mountains in the absence of updrafts.

[FastEddieB]

Instead of giving me books to read I want to hear, in a persuasive way, how my CT at 13,500' can be climbing due to the 49hp (less at the prop) as opposed to due to the lift provided by the wings. This just isn't passing the smell test, say it so I believe it!

In a steady state climb the lift is equal to the weight - or more precisely total "up" forces are exactly balanced by total "down" forces. Even in a CT at 13,500'.

 

At the instant lift is greater than drag, the plane will accelerate upwards, until equilibrium is again established at a greater climb rate. This can only be maintained by excess thrust.

 

Found this cool animation if it helps.

 

http://www.boldmethod.com/cfi-tools/forces-in-a-climb-or-descent/

 

The glider stuff is missing the point. 100Hamburger touched on some of this in his last post. A glider can never achieve a steady state climb in calm air - it has no thrust with which to climb. I assume we all know how a glider does gain altitude, do we not? I can think of four:

 

1) Towed aloft, the excess thrust coming from the tow plane.

 

2) Rising air.

 

3) Stored kinetic energy, i.e. from a dive.

 

4) Surface launch, where the excess kinetic energy is supplied by a vehicle or catapult.

 

None of which are a steady state climb, or the ability to reach a given altitude, which is what we're talking about.

[FastEddieB]

A video on the topic:

 

[FredG]

Eddie, some of this is nomenclature.  Thrust, lift, and weight are all forces that act on an airplane.  In level flight, thrust is perpendicular to gravity and provides no up-going force (i.e., forces that are perpendicular to the surface and in the opposite direction of gravity) on the airplane.  

 

An airplane in level flight must have all up-going forces equal to the weight of the airplane (pounds are a unit of force, which is mass x gravity).  An airplane that is climbing at a steady rate must have forces away from the surface that are greater than its weight.  

 

You can say that the difference between level flight and climbing flight is due to the addition of propeller "thrust" to the "lift" of the wing and another person can simply say that all upward forces are "lift" and that for an airplane to climb the lift exceeds the weight.

 

I think this is the basis for the argument above and it is an issue in terminology, not physics.

 

Just my 2 cents.

[Ed Cesnalis]

Eddie, you're right. thanks

[FastEddieB]

Eddie, some of this is nomenclature...and another person can simply say that all upward forces are "lift" and that for an airplane to climb the lift exceeds the weight.

 

I think this is the basis for the argument above and it is an issue in terminology, not physics.

 

Just my 2 cents.

Maybe that's it.

 

If the question on the FAA test is, "What makes an airplane climb?" and you answer "Lift greater than weight" you will get it wrong.

 

If you answer "Excess thrust" you'll get it right.

 

The issue gets clouded in the bolded portion above, combining two distinct forces, thrust and lift, and combining them into just "lift". If I had a student doing that, I'd assume they had missed some basic definitions and I'd take a step back to define terms again to avoid just such a confusion.