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Buckaroo

Climbing at -6 degrees vs 0 degrees?

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1 hour ago, WmInce said:

In the first line above, it seems your are treating Vx as if it is "an angle." It is not. It is a speed to achieve best angle of climb (max altitude gained for a given distance). And that value changes as the properties of the airfoil changes.

With Vx, climb rate is irrelevent.

Yes its true in this discussion I and we have been referring to Vx as though its and angle where it is a speed.

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1 hour ago, Ed Cesnalis said:

Sorry Tom but that's just silly.  Excess power / Available Thrust is there and used at the pilots discretion.

I can and do put my nose on the horizon and my throttle to the forward stop and in doing so I am applying all Excess power to obtain best speed.

I can and do put my nose at a higher pitch attitude where my rate of climb is maximized and in doing so I am applying all Excess power to obtain best rate of climb.

I can and do put my nose at a higher pitch attitude where my angle of climb is maximized and in doing so I am applying all Excess power to obtain best angle of climb.

I'm free to use settings any where between Vso and Vne.

Excess power effects what I tell it to by where I set the angle of attack.

 

Angle of attack controls speed, not excess power.

Excess power determines rate of climb for the angle of attack (speed) chosen.

Rate is determined by how fast you are going up compared to how fast you are moving forward.

If you choose to increase the angle of attack by putting your nose higher you are controlling your speed, which in this case slows down. Excess power still determines the rate of climb for this angle of attack. You don't control the angle of climb directly. It is a factor of the speed, which you control. Plus the rate of climb determined by the excess power.

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2 hours ago, Tom Baker said:

 

Angle of attack controls speed, not excess power.

Excess power determines rate of climb for the angle of attack (speed) chosen.

Rate is determined by how fast you are going up compared to how fast you are moving forward.

If you choose to increase the angle of attack by putting your nose higher you are controlling your speed, which in this case slows down. Excess power still determines the rate of climb for this angle of attack. You don't control the angle of climb directly. It is a factor of the speed, which you control. Plus the rate of climb determined by the excess power.

Tom,

We have a conflict in our definitions causing us to see differently.

You call it Excess Power - I think you mean any thrust used for climb

I call it available thrust (TA) it is greater than thrust required (TR) and greater than your Excess Power .

It is TA that is available to the pilot to apply towards more speed or steeper climb or faster climb or anything he chooses between stall and Vne.

It is TA that is greater at -6 due to lower drag and results in steeper climb or better rate or faster speed depending on the angle of attack selected by the pilot.

 

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Excess power has never entered as an equation in any light aircraft I’ve flown! My high altitude flights are either full throttle, cruise or idle usually used in high approaches on final. 

My conclusion on all these reads are not mathematical or formulation but seat of the pants experiences in my 125 hours in my CT so far at 4000 feet field elevations at sometimes 90 degrees. 

In conclusion with my 270 lb body and my wife’s 190 lb weight at 25 gallons of gas 15 degrees of flaps gets us over the trees at our 3800 foot runway! If I were to use -6 we’d be eating trees each and every time! 

Simple as that!

 

 

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27 minutes ago, Buckaroo said:

Excess power has never entered as an equation in any light aircraft I’ve flown! My high altitude flights are either full throttle, cruise or idle usually used in high approaches on final. 

My conclusion on all these reads are not mathematical or formulation but seat of the pants experiences in my 125 hours in my CT so far at 4000 feet field elevations at sometimes 90 degrees. 

In conclusion with my 270 lb body and my wife’s 190 lb weight at 25 gallons of gas 15 degrees of flaps gets us over the trees at our 3800 foot runway! If I were to use -6 we’d be eating trees each and every time! 

Simple as that!

 

 

They called me 'Wide Open Throttle Charlie Tango' because that's the throttle setting I use almost all the time.  

At your field I would only depart with 15 degree and climb with that till clear of obstacles and only then clean up, absolutely.  But that's a getting off the ground and beginning your climb in 4 seconds argument.  You start your climb right away not that you climb steeper.  

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I always take advantage of ground effect in all takeoffs! 15 flaps gets us airborne in 1/2 the time as of -6 and then I fly low even towards obstacles in order to take advantage of ground effect and to gain airspeed which everyone needs to stay safe!

When heavy, hot and high, for a minus 6 degree takeoff will plow you in to obstacles at a very killing airspeed! 

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44 minutes ago, Buckaroo said:

I always take advantage of ground effect in all takeoffs! 15 flaps gets us airborne in 1/2 the time as of -6 and then I fly low even towards obstacles in order to take advantage of ground effect and to gain airspeed which everyone needs to stay safe!

When heavy, hot and high, for a minus 6 degree takeoff will plow you in to obstacles at a very killing airspeed! 

I have always done the same at Mammoth. Lots of wind shear, you sometimes get tail gusted.

With our long runway when headed downhill I clean up to -6 and accelerate to 85kts then begin my climb.  I did that at sea level 2 days ago on a long runway and I felt like I was climbing away in a jet not a light sport.

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  • We need empirical data.  What kind of actual test can we do which will give us results to prove which provides a better climb; -6 or 0?  How about a take off which uses a imaginary obstacle to climb over?  One way to do this might be to find a long runway when the wind is calm and record altitude achieved (AGL) when over a landmark using -6 and 0?  Two people needed. One to fly and maintain "best speed" and the other to record altitude when over the landmark.  Perhaps this is a condition we might all be in the same camp on?  Are there any here who believe that 0 or -6 flaps will allow one to clear an obstacle better on a short runway better than 15?  Probably not and this is due to the shorter takeoff roll @ 15.  Where we seem to be disagreeing on is whether -6 provides better climb than 0 when climbing at altitude.  This thread started by asking about clearing box canyons that unexpectedly pop up .  So, to me, the argument is which flap setting provides a better ability to clear a near obstacle.  To get data on this, we need to figure out how to record the altitude achieved over a exact known distance.  However, knowing the exact distance traveled to achieve a target altitude presents a problem. I'm not sure if the GPS will provide accurate distance traveled?  How about you guys that live near lake beds?  Can you cruise at low altitude and start a WOT climb out at a spot near the ground and then accurately record when you're over another landmark at the end of the climb?  Since altitude will be higher than at the start, parallax still might prevent the accurate determination of distance traveled?

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11 hours ago, Buckaroo said:

My conclusion on all these reads are not mathematical or formulation but seat of the pants experiences in my 125 hours in my CT so far at 4000 feet field elevations at sometimes 90 degrees. 

You have 125hrs already?  you must be flying the wings off of that thing daily!   :clap-3332:

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10 hours ago, Buckaroo said:

I always take advantage of ground effect in all takeoffs! 15 flaps gets us airborne in 1/2 the time as of -6 and then I fly low even towards obstacles in order to take advantage of ground effect and to gain airspeed which everyone needs to stay safe!

When heavy, hot and high, for a minus 6 degree takeoff will plow you in to obstacles at a very killing airspeed! 

 

18 minutes ago, FlyingMonkey said:

You have 125hrs already?  you must be flying the wings off of that thing daily!   :clap-3332:

I agree. Its an odd duck to fly and this is the way to become good at it.  It's very maneuverable and tolerates steeper banks then one might think. 

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12 hours ago, Ed Cesnalis said:

Tom,

We have a conflict in our definitions causing us to see differently.

You call it Excess Power - I think you mean any thrust used for climb

I call it available thrust (TA) it is greater than thrust required (TR) and greater than your Excess Power .

It is TA that is available to the pilot to apply towards more speed or steeper climb or faster climb or anything he chooses between stall and Vne.

It is TA that is greater at -6 due to lower drag and results in steeper climb or better rate or faster speed depending on the angle of attack selected by the pilot.

 

Ed, 

We are talking about the same thing, just using different terms. Excess power is the power available beyond what is needed to maintain level flight for climb at a given angle of attack.

It is not power that makes an airplane go faster, it is a decrease in angle of attack. You decrease the angle of attack to go faster, and you use (to use your terms) TR to maintain altitude. Once your new speed is achieved, then any left over TA can be used for climb.

It is the angle of attack that you choose that determines speed, not power. For any weight of the airplane on any given day, there is only one angle of attack for any given speed, regardless of power setting. To maintain level flight there is only one power setting for any given speed, with exception given for the area of reverse command. The excess power is determined by how much power is required to maintain level flight for the given angle of attack. You rate of climb is determined by the excess power available to be used to produce additional lift beyond what is needed to maintain level flight. Best rate of climb is achieved when you have the most excess power compared to drag.

As a pilot you control angle of attack. The airplane and conditions will determine power required to maintain level flight and excess power available. The excess power and angle of attack will determine climb rate. Angle of climb is determined by comparing climb rate to the forward speed of the aircraft

 

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53 minutes ago, Tom Baker said:

Ed, 

We are talking about the same thing, just using different terms. Excess power is

No Available Power (PA) is power that makes the plane go faster or climb. We are using different terms and mean different things, hence the conflict.

 

53 minutes ago, Tom Baker said:

We are talking about the same thing, just using different terms. Excess power is beyond what is needed to maintain level flight for climb at a given angle of attack.

Where does this term 'Excess power' and its definition come from?

 

53 minutes ago, Tom Baker said:

TR to maintain altitude. Once your new speed is achieved, then any left over TA can be used for climb.

You are giving new definitions to 'thrust required' and 'thrust available'

 

Any thrust available [TA] in excess of that required to overcome the drag can be applied to accelerate the vehicle or to cause the vehicle to climb.

 

 

Capture.thumb.PNG.a47d56f3f8b13da75ca44134fbb9e09d.PNG

https://ocw.mit.edu/ans7870/16/16.unified/propulsionS04/UnifiedPropulsion4/UnifiedPropulsion4.htm

 

 

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44 minutes ago, Tom Baker said:

It is the angle of attack that you choose that determines speed, not power. For any weight of the airplane on any given day, there is only one angle of attack for any given speed, regardless of power setting. To maintain level flight there is only one power setting for any given speed, with exception given for the area of reverse command. The excess power is determined by how much power is required to maintain level flight for the given angle of attack. You rate of climb is determined by the excess power available to be used to produce additional lift beyond what is needed to maintain level flight. Best rate of climb is achieved when you have the most excess power compared to drag.

As a pilot you control angle of attack. The airplane and conditions will determine power required to maintain level flight and excess power available. The excess power and angle of attack will determine climb rate. Angle of climb is determined by comparing climb rate to the forward speed of the aircraft

Your altered definitions result in altered theory.

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@WmInce @FlyingMonkey

You guys are with Tom on this argument.

Notice above Tom's theory was based on his own terms and definitions that produce altered theory.

The altered theory fails to illuminate the the -6 configuration has more (TA) thrust available and therefore can achieve a steeper angle of climb.

The altered theory re-allocates TA to TR and uses the term Excess Power instead and now the -6 advantage disappears into thrust required.

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Ed, I looked it up and I was using the wrong term. Instead of excess I should have been using reserve. Any way it is the available power/thrust beyond what is required to maintain level flight.

Power has nothing to do with speed! Angle of attack is what controls speed. I can fly the airplane at any speed between stall and VNE regardless of power. To go faster you decrease the angle of attack, to go slower you increase the angle of attack. Power will determine if you are descending, maintaining level flight, or climbing. Any power that is left available beyond what it takes to maintain level flight can be used for climb.

You are confusing the fact that it is the increase in power that is making you go faster, when that is not the case. If you increase power with no other changes you will climb. That is because of the reserve power beyond what was needed to maintain level flight in that configuration.

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1 hour ago, Ed Cesnalis said:

 

 

Any thrust available [TA] in excess of that required to overcome the drag can be applied to accelerate the vehicle or to cause the vehicle to climb.

 

 

Capture.thumb.PNG.a47d56f3f8b13da75ca44134fbb9e09d.PNG

https://ocw.mit.edu/ans7870/16/16.unified/propulsionS04/UnifiedPropulsion4/UnifiedPropulsion4.htm

 

 

Notice they use the term excess. You can use thrust to overcome drag to accelerate, but it is the decrease in angle of attack that allows that to happen. If you don't decrease the angle of attack all you will get is a climb at the same airspeed.

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6 minutes ago, Tom Baker said:

Ed, I looked it up and I was using the wrong term. Instead of excess I should have been using reserve. Any way it is the available power/thrust beyond what is required to maintain level flight.

Power has nothing to do with speed! Angle of attack is what controls speed. I can fly the airplane at any speed between stall and VNE regardless of power. To go faster you decrease the angle of attack, to go slower you increase the angle of attack. Power will determine if you are descending, maintaining level flight, or climbing. Any power that is left available beyond what it takes to maintain level flight can be used for climb.

You are confusing the fact that it is the increase in power that is making you go faster, when that is not the case. If you increase power with no other changes you will climb. That is because of the reserve power beyond what was needed to maintain level flight in that configuration.

You cannot resolve your theory with this statement from the lesson I posted:

Quote

Any thrust available in excess of that required to overcome the drag can be applied to accelerate the vehicle (increasing kinetic energy) or to cause the vehicle to climb (increasing potential energy).

 

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3 minutes ago, Tom Baker said:

Notice they use the term excess. You can use thrust to overcome drag to accelerate, but it is the decrease in angle of attack that allows that to happen. If you don't decrease the angle of attack all you will get is a climb at the same airspeed.

They apply the term excess to 'that required to overcome the drag'  -  see the differnce?  TR is only thrust for lift and drag, the rest can be used for climb or speed.  

You are arguing against this theory not with it.

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2 hours ago, Tom Baker said:

It is not power that makes an airplane go faster, it is a decrease in angle of attack. You decrease the angle of attack to go faster, and you use (to use your terms) TR to maintain altitude. Once your new speed is achieved, then any left over TA can be used for climb.

It is the angle of attack that you choose that determines speed, not power. For any weight of the airplane on any given day, there is only one angle of attack for any given speed

 

This seems counter to experience.  Two puzzles in my brain:

1)  How does an airplane accelerate on a runway from a stop, when the angle of attack is unchanging?

2)  If in calm winds I am flying at fast cruise speed and add power, the airplane accelerates.  The angle of attack has not changed, since the relative wind was already directly opposed to my direction of travel.  Going faster doesn't change the angle of the relative wind, only its velocity.  Now it is true that trimming for the new speed is required, but that is because at the new speed the wing creates more lift and requires additional downforce to counter.  But increasing AoA creates more lift, and in this scenario if anything we'd be *reducing* AoA by accelerating.   I'm not sure, but don't see how a stronger relative wind changes the angle at which it strikes the airfoil...

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@Tom Baker

Theory limits TR more than you do and has more TA at low drag configurations.

When you assign thrust needed for level flight at increased speeds to TR you steal TA from the low drag setting that is used in climb.

 Below is the correct theory:

Quote

Any thrust available [TA] in excess of that required to overcome the drag can be applied to accelerate the vehicle or to cause the vehicle to climb.

When you deviate from this you invent your own theory. Your theory gets different results, both can't be correct.

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2 minutes ago, Ed Cesnalis said:

They apply the term excess to 'that required to overcome the drag'  -  see the differnce?  TR is only thrust for lift and drag, the rest can be used for climb or speed.  

You are arguing against this theory not with it.

You are pulling bits and pieces trying to make your point, kind of like how the media works.  here is more of the quote you just used. "Any thrust available in excess of that required to overcome the drag" The excess thrust is not the thrust being used to overcome drag it is the thrust that is left over after the drag has been overcome.

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1 minute ago, FlyingMonkey said:

This seems counter to experience.  Two puzzles in my brain:

1)  How does an airplane accelerate on a runway from a stop, when the angle of attack is unchanging?

2)  If in calm winds I am flying at fast cruise speed and add power, the airplane accelerates.  The angle of attack has not changed, since the relative wing was already directly opposed to my direction of travel.  Going faster doesn't change the angle of the relative wind, only its velocity.  Now it is true that trimming for the new speed is required, but that is because at the new speed the wing creates more lift and requires additional downforce to counter.  But is that due to increasing AoA of the wing?  I'm not sure, but don't see how a stronger relative wind changes the angle at which it strikes the airfoil...

1) power provides speed not angle of attack

2) I was thinking the same, maybe there is a small lowering of angle that we don't perceive but clearly power produces speed.

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4 minutes ago, FlyingMonkey said:

This seems counter to experience.  Two puzzles in my brain:

1)  How does an airplane accelerate on a runway from a stop, when the angle of attack is unchanging?

2)  If in calm winds I am flying at fast cruise speed and add power, the airplane accelerates.  The angle of attack has not changed, since the relative wing was already directly opposed to my direction of travel.  Going faster doesn't change the angle of the relative wind, only its velocity.  Now it is true that trimming for the new speed is required, but that is because at the new speed the wing creates more lift and requires additional downforce to counter.  But is that due to increasing AoA of the wing?  I'm not sure, but don't see how a stronger relative wind changes the angle at which it strikes the airfoil...

1. Angle of attack is defined by the angle of the relative wind and the cord line. When you are sitting on the runway you have no relative wind.

2. When you increase throttle you will climb not go faster, unless you decrease the angle of attack. That is why you have to re-trim the airplane for the new speed.

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