Flaps to aid climbing - truth or fiction

[Tom Baker]

So, to make sure I'm digesting this right:

 

In your test, when you thought you had a better climb rate with flaps, you were actually pretty close to clean?

 

The way I read it he had 10° instead of 15°, but what he thought was clean actually had some reflex. That being the case he didn't test in the clean configuration.

[Roger Lee]

You can debate book theory all day, but it does not take into account pilot and plane variables or specific plane performance and design. So a book may look and sound good, but maybe not to a specific instance or plane. It becomes general fact and not specific fact.

 

 

Even if ED's test had flaps some what off you still have 1800+ CT's that climb higher sooner than with zero flaps at takeoff and the heavier you are the more noticeable. His test would still be valid it just wasn't with the exact flap settings he thought. If you are a 175 lb. solo pilot the results are less dramatic verses a plane that is really heavy with two people, full fuel and baggage..At 1475 lbs up at Bryce Canyon airport in October I probably couldn't get off the ground in zero flaps, but I can with 15 flaps. Site all the books you want this is fact and has been for 7 -8 years. If you are heavy you have one damn long roll and increased ground speed with zero flaps, but 15 gets you off the ground sooner and allows faster climb over  zero by the time you are at the end of the runway or a little past where you might make in-flight adjustments.

I see lots of CT's and some flap settings are off a tad. They are position controlled by a potentiometer and are easily re-settable for accuracy.

If he has a -10 verses a -6 it will lessen his climb just a tad at high altitude over -6. I know several that have -12 like many other CT;s do out of the US. Zero flaps at high altitude climb better and allow a slightly better nose orientation in cruise, but it does affect the top end speed a tad.  I know someone that has been over 18K in the CT, but that was not obtainable in -6 flaps and had to be done in zero. I did all this testing years ago back in 2007. I tested -6 top speed over -12 and found no real advantage because the prop and pilot on most planes were the determining factor. If you really want to see these affects amplified and more tangible evidence fly the CT at 1475 Lbs. and all your results will stand out including the fact that it gets off the ground faster and climbs higher in a shorter distance than zero flaps do. You may loose some speed at 15 flaps, but they climb faster.  I don't care about extra speed at takeoff I'm well above what I need to be and that's controllable with the stick. What I want is faster climb to have the most altitude by the time I reach the end of the runway. Normal is 15 flaps at 60 knts. Some seem to like 65 better and some 55, but they are all in the ballpark.

 I can tell you ED's prop (a Warp) climb performance is less than a Neuform and a Sensenich. Top speed though is the same. (Months of testing a dozen props)

 

I hate to really get into this because it makes no difference what the book says this is real life tangible actionable and reproducible  results. Read all the books you want, but unless you go do real time variable controlled testing the books are just  general theory against real time actionable testing on a SPECIFIC plane not to mention the books take no variables into accountability for an individual's test run and there are lots of variables that most pilots never consider because that's just normal operations to them.

 

We all having little differences in our flying which will make our results different.

[Ed Cesnalis]

Roger,

 

I agree with your conclusion.  When flying my CT I work with what works and don't look to the book.

 

Much of your  argument is focused on best angle (like what you get at Vx) where this argument is focused on what setting has best rate (like what you get at Vy) and what happens to the relationships of best rate when below and at or above service ceiling.

 

Here's the scenario that will full the pilot:  flight path needs to clear high terrain, best/good climb at zero flaps isn't clearing the terrain and a last minute boost is needed.  The pilot deploys 15* and the flight path improves and the terrain was easily cleared.  Now what really happened?  Was it the initial balloon stabilizing at a stepper angel but lesser rate that got the pilot over without turning away? If it was a last minute adjustment the answer was likely yes.

 

If the flap increase was done farther out and it had time to stabilize and it stabilized at best climb rate and if the excess thrust theory is working in this case the pilot would then have to pitch up for a better angle.  

 

I'm seeing that service or absolute or personal (due to proximity of stall speed) ceilings are quite different for each of the 3 flap settings.  If you are at an attitude where you have reached the ceiling for one setting but not the other 2 or other 1 then more flaps will get you higher.

[Andy]

I've experienced the same things you guys and often use 0 or 15 to get a better climb, depending on the circumstance. As a pilot, there are always other tricks you can play to get more instantaneous climb rate, like trading kinetic for potential energy.  That said, the correct theory for a steady-state climb is that it is a factor of excess thrust, which is the difference between thrust required and available.  Thrust required is a factor of overall drag.  To figure out what the flap deflections are actually doing (other than affecting excess trust) would take more time and resources than I've got, but it still the right place to look...at least from an engineering standpoint.

[gbigs]

I've experienced the same things you guys and often use 0 or 15 to get a better climb, depending on the circumstance. As a pilot, there are always other tricks you can play to get more instantaneous climb rate, like trading kinetic for potential energy.  That said, the correct theory for a steady-state climb is that it is a factor of excess thrust, which is the difference between thrust required and available.  Thrust required is a factor of overall drag.  To figure out what the flap deflections are actually doing (other than affecting excess trust) would take more time and resources than I've got, but it still the right place to look...at least from an engineering standpoint.

 

Excess thrust does not explain how a glider gets higher.  To fully understand climb in both powered and non powered you MUST chracterize lift from the energy not just in thrust but in density of air, thermals, ridge and wave winds around mountains.  Also, there is a speed limit regarding flaps ( except 0 and -6).

[Doug G.]

Excess thrust does not explain how a glider gets higher. To fully understand climb in both powered and non powered you MUST chracterize lift from the energy not just in thrust but in density of air, thermals, ridge and wave winds around mountains. Also, there is a speed limit regarding flaps ( except 0 and -6).

You need to understand potential and kinetic energy and thermal lift.

Without thermal lift a glider does not gain altitude. You put it on the runway, it will gain no altitude without energy input. In the air it still will gain no altitude without energy input. Once you have energy you can convert between potential and kinetic. You can do that with a CT too.

[Doug G.]

Flaps change the shape of the airfoil, especially with our ailerons also reacting with the flaps. (Flaperons?) The flap settings increase the lift available while also increasing the drag. When the air is thin the lift is more important than the airfoil efficiency.

[Andy]

Burgers, my post only pertained to powered aircraft..like the CT.  Analyzing performance for a glider is a completely different deal, since thrust falls out of the picture.  I've used thermals lots of times to gain altitude when, in a high density altitude situation, there was no more excess thrust to be had.  When I use the term "lift" I am using it to describe the action due to the aerodynamics associated with an airfoil, not other actors like a rising column of air.

[Tom Baker]

Excess thrust does not explain how a glider gets higher.  To fully understand climb in both powered and non powered you MUST chracterize lift from the energy not just in thrust but in density of air, thermals, ridge and wave winds around mountains.  Also, there is a speed limit regarding flaps ( except 0 and -6).

 

I already explained once for you how gliders get higher, but I will explain again. Not taking into account diving and using that energy to climb, a glider requires some kind of energy to get in the air. This energy can come from gravity, a winch, a car, towed by an airplane, or self propulsion. Once in the air a glider is always descending in the air mass. Because of the glide ratio of a glider being so good they descend at a very slow rate. If the rate of the air mass is rising faster than the glider is descending through it, it will gain altitude.

 

 

Even an airplane with the engine shut off and a lower glide ratio can stay aloft in strong lift, as long as the rising air is going up at a rate greater than the airplane is descending.

I have heard that years ago they would fly airplanes like Cubs and Taylorcrafts to glider meets out west in the mountains. They would remove the propeller and install a glider tow release on the propeller shat and use them in the contest.

[gbigs]

Flaps change the shape of the airfoil, especially with our ailerons also reacting with the flaps. (Flaperons?) The flap settings increase the lift available while also increasing the drag. When the air is thin the lift is more important than the airfoil efficiency.

 

A flaperon is a combined aileron and flap...no separate flaps.  The CT has separate ailerons and flaps.

[Ed Cesnalis]

The CT has separate flaperons and flaps.  The flaperons deploy deferentially plus they droop, this dual purpose makes them flaperons not ailerons.

[Tom Baker]

A flaperon is a combined aileron and flap...no separate flaps.  The CT has separate ailerons and flaps.

 

The fact that the CT has flaperons is why the AOI/POH suggest using not more than 15° flap setting for crosswind landings.

[Ed Cesnalis]

A flaperon is a combined aileron and flap...no separate flaps.  The CT has separate ailerons and flaps.

 

I had that configuration on my first home built.  Its called a full span flaperon.

[gbigs]

The CT has separate flaperons and flaps.  The flaperons deploy deferentially plus they droop, this dual purpose makes them flaperons not ailerons.

 

The POH refers to the flaps as flaps and the ailerons as ailerons (there is no term 'flaperon' in the POH for the CT).  A flaperon is a single continuous trailing edge device that combines both together - the Kitfox I think had those as does the Aerotrek for example.

[Ed Cesnalis]

The POH doesn't use the term flapreon but that doesn't make it the wrong term.  It is certainly more precise than aileron.  Just because Kitfox and a few others use them full span that doesn't make full span part of the definition.  The definition focuses on the combined function not the width.

 

When I deploy flaps my 'ailerons' move too, they both droop, that makes them more than ailerons.

 

A "flaperon" (a portmanteau word) on an aircraft's wing is a type of control surface that combines the functions of both flaps and ailerons. Some smaller kitplanes have flaperons for reasons of simplicity of manufacture, while some large commercial aircraft may have a flaperon between the flaps and aileron.

Flaperon - Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Flaperon

Wikipedia

 

[Tom Baker]

The POH refers to the flaps as flaps and the ailerons as ailerons (there is no term 'flaperon' in the POH for the CT).  A flaperon is a single continuous trailing edge device that combines both together - the Kitfox I think had those as does the Aerotrek for example.

 

Regardless of what the POH says, anytime you have ailerons that move up and down with the flaps they are flaperons.

[Doug G.]

A flaperon is a combined aileron and flap...no separate flaps. The CT has separate ailerons and flaps.

Wrong.

[gbigs]

 

The POH doesn't use the term flapreon but that doesn't make it the wrong term.  It is certainly more precise than aileron.  Just because Kitfox and a few others use them full span that doesn't make full span part of the definition.  The definition focuses on the combined function not the width.

 

When I deploy flaps my 'ailerons' move too, they both droop, that makes them more than ailerons.

 

A "flaperon" (a portmanteau word) on an aircraft's wing is a type of control surface that combines the functions of both flaps and ailerons. Some smaller kitplanes have flaperons for reasons of simplicity of manufacture, while some large commercial aircraft may have a flaperon between the flaps and aileron.

Flaperon - Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Flaperon

Wikipedia

 

 

 

The POH doesn't say flaperon because the CT doesn't have flaperons.  The definition you gave says "a control surface that combines both flaps and aileron."  The Aerotrek (modeled after kitfox) has a flaperon which is a single moveable control on the trailing edge of the wing. The Aerotrek POH refers to the device as a flaperon.  I am told that is done to save costs.

 

The CT has separate flaps and ailerons.  The flaps move independent of the ailerons as you know (flaps with motors, ailerons from stick movement).  My Cirrus has the same configuration.   And the Cirrus OPS manual also does not use the term flaperon but instead refers to flaps and their operation, and the ailerons and their operation.

[Doug G.]

The POH doesn't say flaperon because the CT doesn't have flaperons. The definition you gave says "a control surface that combines both flaps and aileron." The Aerotrek (modeled after kitfox) has a flaperon which is a single moveable control on the trailing edge of the wing. The Aerotrek POH refers to the device as a flaperon. I am told that is done to save costs.

 

The CT has separate flaps and ailerons. The flaps move independent of the ailerons as you know (flaps with motors, ailerons from stick movement). My Cirrus has the same configuration. And the Cirrus OPS manual also does not use the term flaperon but instead refers to flaps and their operation, and the ailerons and their operation.

Wrong again. The ailerons move down with the flaps. Flaperons are always separate from the flaps. Please look it up or take the word of people who know what flaperons are instead of just repeating yourself. That is how one learns.

[Tom Baker]

The POH doesn't say flaperon because the CT doesn't have flaperons.  The definition you gave says "a control surface that combines both flaps and aileron."  The Aerotrek (modeled after kitfox) has a flaperon which is a single moveable control on the trailing edge of the wing. The Aerotrek POH refers to the device as a flaperon.  I am told that is done to save costs.

 

The CT has separate flaps and ailerons.  The flaps move independent of the ailerons as you know (flaps with motors, ailerons from stick movement).  My Cirrus has the same configuration.   And the Cirrus OPS manual also does not use the term flaperon but instead refers to flaps and their operation, and the ailerons and their operation.

 

How long did you have your CTLSi, and you didn't know that the ailerons move up and down with the flaps? I don't know where you can find it in your POH, but the copy I have saved to my computer has it on page 7-15, paragraph 7.3.5. It explains how the aileron works, and that it moves with the flaps through a mixer.

[gbigs]

Wrong again. The ailerons move down with the flaps. Flaperons are always separate from the flaps. Please look it up or take the word of people who know what flaperons are instead of just repeating yourself. That is how one learns.

 

No. The ailerons and the flaps are INDEPENDENT of each other.  Move the ailerons with the stick, the flaps with a switch and set of motors.  Tired of your patronizing tone by the way.

[gbigs]

How long did you have your CTLSi, and you didn't know that the ailerons move up and down with the flaps? I don't know where you can find it in your POH, but the copy I have saved to my computer has it on page 7-15, paragraph 7.3.5. It explains how the aileron works, and that it moves with the flaps through a mixer.

 

The phrase "when flaps are extended, the ailerons follow the flaps to a certain amount."   The language is a rough translation of German and has an ambiguous meaning.  But in essence this says nothing more than  the flaps and the ailerons are next to each other on the back edge of the wing and may appear to move appear together "to a certain amount" in the same direction but that would only happen coincidentally since they are not connected to each other.  Each is controlled and moved independently..

 

A flaperon is a SINGLE control surface, not split into two pieces.  If you want to see one check out the Zodiak Jeep and the Aerotrek. 

[Ed Cesnalis]

Would you believe a video?

[ralarcon]

Would you believe a video?

That sounds interesting.

 

Cheers

[FastEddieB]

Would you believe a video?

I'd like to see it!

 

I believe those saying that the ailerons move down a bit with flap extension, becoming de facto flaperons, but it's a fairly unusual arrangement. It would seem to add a level of complexity for only a small modicum of benefit. Which I assume is why it's so rarely used.

 

BTW, the POH says there's a "mixer" which interconnects the flaps and ailerons, so Cecil is clearly wrong about them being completely independent, as he stated here:

 

"But in essence this says nothing more than the flaps and the ailerons are next to each other on the back edge of the wing and may appear to move appear together "to a certain amount" in the same direction but that would only happen coincidentally since they are not connected to each other. Each is controlled and moved independently..."