Colorado Springs

[tspear]

@Clark1961
Try again. I do like to debate, and I do admit when wrong. I also like to debate both sides of an argument, and in almost all cases I can argue either side. Pick a topic and I can provide examples . Lastly stating opinions without fact is not very interesting to debate.

@denverpilot
I have actually read the whole series, and I have taken it apart with engineers and mathematicians. I did this as part of a debate where I stated repeatedly that the plane stalls at the same speed regardless of altitude, which was based on what I was taught by the first couple of CFIs and also what I read in some literature about angle of attack gauges. I lost. Here was test an engineer CFI had me do with him. Take the Cirrus up with full fuel, and test the stall speed and power requirements at 12K density altitude. Note how much fuel was burned before the test. Record the power and speed. Land, top off the tanks. Fly to 9K, burn off the fuel to get back to same weight as 12K before repeating the stall test. Repeat process at 6K and 3K (I was based around DC, so effectively near sea level).
Was there a difference, yes. Was it substantial, not really. Was it enough for me to notice, yes. Most pilots today are so sloppy in the controls and fly with enough margin it likely does not matter. However, if you fly near the margins of the plane, it does matter.
And in the example, a 20HP difference is a 10% power change in the Cirrus SR20. The less power a plane has, the greater this is likely a factor.

Tim

 

[Clark1961]

@Clark1961
Try again. I do like to debate, and I do admit when wrong. I also like to debate both sides of an argument, and in almost all cases I can argue either side. Pick a topic and I can provide examples . Lastly stating opinions without fact is not very interesting to debate.

Try what again? Explaining to you that you are confusing indicated and true airspeeds? It’s pointless since you’ve dug your feet in and refuse to admit your error. If you change your tune and behave reasonably then I’d be happy to explain things in greater detail. As long as you remain obstinate and use obfuscation as a tactic I’ll just treat you as just another pointless internet idiot.

 

[SkyHog]

@Clark1961
Try again. I do like to debate, and I do admit when wrong. I also like to debate both sides of an argument, and in almost all cases I can argue either side. Pick a topic and I can provide examples . Lastly stating opinions without fact is not very interesting to debate.

@denverpilot
I have actually read the whole series, and I have taken it apart with engineers and mathematicians. I did this as part of a debate where I stated repeatedly that the plane stalls at the same speed regardless of altitude, which was based on what I was taught by the first couple of CFIs and also what I read in some literature about angle of attack gauges. I lost. Here was test an engineer CFI had me do with him. Take the Cirrus up with full fuel, and test the stall speed and power requirements at 12K density altitude. Note how much fuel was burned before the test. Record the power and speed. Land, top off the tanks. Fly to 9K, burn off the fuel to get back to same weight as 12K before repeating the stall test. Repeat process at 6K and 3K (I was based around DC, so effectively near sea level).
Was there a difference, yes. Was it substantial, not really. Was it enough for me to notice, yes. Most pilots today are so sloppy in the controls and fly with enough margin it likely does not matter. However, if you fly near the margins of the plane, it does matter.
And in the example, a 20HP difference is a 10% power change in the Cirrus SR20. The less power a plane has, the greater this is likely a factor.

Tim

Was this true airspeed, calibrated airspeed, or indicated airspeed?

 

[JCranford]

Its all plains up until the point that it isn't. Don't enter passes, and don't fly over massive mountains...

I assume this comment was specific to the sightseeing in the Warrior? I fully intend to fly from Texas to Oregon early next year. That's gonna be difficult without flying over massive mountains unless I do a fairly big divert.

 

[tspear]

Was this true airspeed, calibrated airspeed, or indicated airspeed?

Indicated. In the Cirrus SR20 we saw between one and two knots difference for each 3K of density altitude; and between 3K and 12K, the difference was just over 3 knots. Oh, this was to horn, not actual stall break.

Tim

 

[Mtns2Skies]

Lastly stating opinions without fact is not very interesting to debate.

Basic laws of physics really aren't opinions. I'm not sure how you believe your anecdotal data of "I saw a difference when I stalled the plane" really counts as data at all. If you REALLY wanted to do this you'd need to define the stall region very specifically and also do it maybe 50 times with computer data monitoring all of this.

I'm going to say this once and I have no intention of debating this further with you because you refuse to acknowledge basic Newtonian physics. Indicated airspeed is the mass flow rate of air molecules over the aircraft. The plane is actually unable to know ANY difference at different altitudes based on the same indicated airspeed... its very simple.

 

[Mtns2Skies]

I assume this comment was specific to the sightseeing in the Warrior? I fully intend to fly from Texas to Oregon early next year. That's gonna be difficult without flying over massive mountains unless I do a fairly big divert.

Definitely... a 210 is a solid mountain plane

 

[murphey]

I assume this comment was specific to the sightseeing in the Warrior? I fully intend to fly from Texas to Oregon early next year. That's gonna be difficult without flying over massive mountains unless I do a fairly big divert.

Depends on your definition...Follow I-80 as far as you can, very manageable in a warrior.

 

[tspear]

Basic laws of physics really aren't opinions. I'm not sure how you believe your anecdotal data of "I saw a difference when I stalled the plane" really counts as data at all. If you REALLY wanted to do this you'd need to define the stall region very specifically and also do it maybe 50 times with computer data monitoring all of this.

I'm going to say this once and I have no intention of debating this further with you because you refuse to acknowledge basic Newtonian physics. Indicated airspeed is the mass flow rate of air molecules over the aircraft. The plane is actually unable to know ANY difference at different altitudes based on the same indicated airspeed... its very simple.

Actually, KIAS is measure of the difference between static and dynamic air pressure. The same mechanical limitations of the airspeed indicator also apply also to the altimeter.
Airfoils stall when the boundary layer can no longer remain "attached". Until you get to higher altitudes and speeds, the airfoil will normally stall at a specific angle of attack. For our purposes, we can basically ignore the higher altitude and compressibility effects on the angle of attack. This is typically where the airspeed has exceeded ~0.4 mach. So we can discount the effect on our low/slow piston planes.
Since most certified aircraft do not have an AOA probe, we normally use airspeed as a proxy to the angle of attack. This has limitations, the obvious ones most people thing of is weight and/or CG.
However, it is also affected by temperature; hence why the ICAO and now the FAA have been adding temp warning on IFR approach plates because temperature affects the altimeter. Your airspeed indicator is susceptible to the same errors.
As an example of temp affecting the KIAS, look at the page 5-21 of the following POH:
http://www.jasonblair.net/wp-content/uploads/2015/06/Beechcraft-Bonanza-A36-AFM.pdf
For the same altitude and power settings, you will see a 2-3 difference in the calibrated airspeed based on the temp change of 20 degrees from ISA.
In the test I performed with the CFI engineer, this was the actual effect. If I had an AOA probe, it would have always stalled at the exact same angle.

Tim

 

[denverpilot]

For the same altitude and power settings, you will see a 2-3 difference in the calibrated airspeed based on the temp change of 20 degrees from ISA.

So if we stipulate to this silliness, and apply this to the real world, you’re going to adjust your approach speed by 2 knots on a hot day here. And nearly nothing on a normal day. LOL.

You’re talking about the largest factor now, temperature, and it’s a 2 knot difference.

Your original assertion was you were going to fly an approach here at a much higher speed than necessary. That would still be wrong.

 

[Clark1961]

So if we stipulate to this silliness, and apply this to the real world, you’re going to adjust your approach speed by 2 knots on a hot day here. And nearly nothing on a normal day. LOL.

You’re talking about the largest factor now, temperature, and it’s a 2 knot difference.

Your original assertion was you were going to fly an approach here at a much higher speed than necessary. That would still be wrong.

Worse than that since he said he’d call someone to ask what speed to fly. Final approach is 1.3Vso so that speed would change less than 1 kt. The guy is unreasonable to say the least.

 

[tspear]

So if we stipulate to this silliness, and apply this to the real world, you’re going to adjust your approach speed by 2 knots on a hot day here. And nearly nothing on a normal day. LOL.

You’re talking about the largest factor now, temperature, and it’s a 2 knot difference.

Your original assertion was you were going to fly an approach here at a much higher speed than necessary. That would still be wrong.

Actually I said ask; and could have been more clear since I was really trying to say, ask two different questions.
But then this got into a ****ing match, with insults. And at that point, I got technical to argue the point.
Anyway, the reason I stated ask was I was thinking of a two different things.
1. I have known a fair number of pilots that fly throttle position or sound. This is effectively often flying based on rough power settings. The power settings you need change with altitude. So that should have been the first point. For these settings, rough elevation is generally going to get you into the ball park.
2. Ask pilots about local conditions, especially if a shorter runway. When flying in mountains or near the sea you are more likely to get odd mechanically induced gust/wind patterns. These can be beneficial or harmful. For example, having flown into Laramie WY a few times, with the extra long runway available multiple pilots suggested I carry an extra ten to fifteen knots in the Aerostar as you come over the ridge line. When flying into Smoketown PA in the Cirrus, there is usually a wind shift as you break the treeline; most people coming in based on gusting winds carry to much speed and burn brakes. So instead of 1.3 plus 1/2 gust speed; you should be planning on 1.2 + 1/2 gust as you cross the treeline, or even a bit less.

Oh, in terms of adjust by a couple of knots. I actually try and do so;. am I successful, not often. But I do try!

Tim

 

[Stan Cooper]

https://www.ntsb.gov/_layouts/ntsb....?queryId=e2d506cf-289d-4710-9153-37e8f0d441be (NTSB No. DEN06FA111)

The pilot of the Piper Arrow in this 2006 fatal accident, Geoff Peck, was a friend of mine. He was a CFI, held an ATP certificate, and was returning to California after spending a week at Oshkosh AirVenture. He taught mountain flying.

My point is, even very experienced pilots can get into trouble in the mountains if they forget the basics (or don't know them).

 

[denverpilot]

Actually I said ask; and could have been more clear since I was really trying to say, ask two different questions.
But then this got into a ****ing match, with insults. And at that point, I got technical to argue the point.
Anyway, the reason I stated ask was I was thinking of a two different things.
1. I have known a fair number of pilots that fly throttle position or sound. This is effectively often flying based on rough power settings. The power settings you need change with altitude. So that should have been the first point. For these settings, rough elevation is generally going to get you into the ball park.
2. Ask pilots about local conditions, especially if a shorter runway. When flying in mountains or near the sea you are more likely to get odd mechanically induced gust/wind patterns. These can be beneficial or harmful. For example, having flown into Laramie WY a few times, with the extra long runway available multiple pilots suggested I carry an extra ten to fifteen knots in the Aerostar as you come over the ridge line. When flying into Smoketown PA in the Cirrus, there is usually a wind shift as you break the treeline; most people coming in based on gusting winds carry to much speed and burn brakes. So instead of 1.3 plus 1/2 gust speed; you should be planning on 1.2 + 1/2 gust as you cross the treeline, or even a bit less.

Oh, in terms of adjust by a couple of knots. I actually try and do so;. am I successful, not often. But I do try!

Tim

So the initial point was still as useless as tits on a boar, and wrong considering nobody adjusts speed in a Cirrus for landing by 2 knots and the power setting changes you’re mentioning can’t be read because they’re so small on the instrument in the cockpit...

... but now we’re talking about specific terrain features of specific airports to try to cover that up and move on... fly a little faster at Laramie because you might get mechanical turbulence.

Got it. LOL.

 

[Clark1961]

So the initial point was still as useless as tits on a boar, and wrong considering nobody adjusts speed in a Cirrus for landing by 2 knots and the power setting changes you’re mentioning can’t be read because they’re so small on the instrument in the cockpit...

... but now we’re talking about specific terrain features of specific airports to try to cover that up and move on... fly a little faster at Laramie because you might get mechanical turbulence.

Got it. LOL.

Last I checked the ridge is about 20 miles from LAR. Final approach isn’t relevant that far out even for an Aerostar.

 

[Tarheelpilot]

Actually I said ask; and could have been more clear since I was really trying to say, ask two different questions.
But then this got into a ****ing match, with insults. And at that point, I got technical to argue the point.
Anyway, the reason I stated ask was I was thinking of a two different things.
1. I have known a fair number of pilots that fly throttle position or sound. This is effectively often flying based on rough power settings. The power settings you need change with altitude. So that should have been the first point. For these settings, rough elevation is generally going to get you into the ball park.
2. Ask pilots about local conditions, especially if a shorter runway. When flying in mountains or near the sea you are more likely to get odd mechanically induced gust/wind patterns. These can be beneficial or harmful. For example, having flown into Laramie WY a few times, with the extra long runway available multiple pilots suggested I carry an extra ten to fifteen knots in the Aerostar as you come over the ridge line. When flying into Smoketown PA in the Cirrus, there is usually a wind shift as you break the treeline; most people coming in based on gusting winds carry to much speed and burn brakes. So instead of 1.3 plus 1/2 gust speed; you should be planning on 1.2 + 1/2 gust as you cross the treeline, or even a bit less.

Oh, in terms of adjust by a couple of knots. I actually try and do so;. am I successful, not often. But I do try!

Tim

Your understanding of this matter is way off. You should listen more and talk less.

 

[Clark1961]

Your understanding of this matter is way off. You should listen more and talk less.

My opinion is that he wasn’t trying to understand the matter. He was trying to insert himself as an expert and failed miserably.

 

[Tarheelpilot]

My opinion is that he wasn’t trying to understand the matter. He was trying to insert himself as an expert and failed miserably.

Whatever the motivation it was clear his understanding of aerodynamics was guiding him towards unnecessarily high approach speeds at high altitude airports which is terribly unsafe. I don’t care if he ever admits to being wrong on this board as long as he now understands the flaw in his logic and will change how he handles high DA approaches.

 

[Clark1961]

Whatever the motivation it was clear his understanding of aerodynamics was guiding him towards unnecessarily high approach speeds at high altitude airports which is terribly unsafe. I don’t care if he ever admits to being wrong on this board as long as he now understands the flaw in his logic and will change how he handles high DA approaches.

I do think he needs to admit his ignorance here after claiming expertise. It is a point of actually learning. Of course he won’t do it and will forever proclaim he is right.

 

[Clark1961]

On a side note I shall forever attempt to fly two knots faster than book speed when landing at density altitudes above 15,000 feet. This is a commitment freely made before a worldwide audience. Of course book speed will be adjusted for gross weight, phase of the moon and Eötvös.

 

[MtnMarcus]

Try what again? Explaining to you that you are confusing indicated and true airspeeds? It’s pointless since you’ve dug your feet in and refuse to admit your error. If you change your tune and behave reasonably then I’d be happy to explain things in greater detail. As long as you remain obstinate and use obfuscation as a tactic I’ll just treat you as just another pointless internet idiot.

What does obfuscation mean?

 

[Clark1961]

What does obfuscation mean?

Would you like me to google that for you my lord?

 

[MtnMarcus]

Would you like me to google that for you my lord?

as I am sure you did as you were posting. Just don't here it often....if ever.

 

[Clark1961]

as I am sure you did as you were posting. Just don't here it often....if ever.

No, I don’t need to google obfuscate. I deal with it regularly from folks who have a high opinion of themselves when they get called on their BS.

 

[denverpilot]

as I am sure you did as you were posting. Just don't here it often....if ever.

It’s pretty common in tech circles. Usually in reference to attempting to hide how a system works. It’s also common in discussions of politicians and stuff they do for a living.

Here’s the context I usually see it in, in my day job.

http://searchsoftwarequality.techtarget.com/definition/obfuscation

We even have software on our public websites that does simple obfuscation of the code that displays the website. Makes it not fun to open up the source code sent by the web server and read it. The code still does the exact same thing the human-readable code does that it’s based off of, but it’s nearly impossible for a human to read it.

Of course any bright human just puts that code back through a reverse-obfuscation piece of software if they’re trying to reverse engineer it, but it keeps a casual viewer from looking at what it does. Whether or not it’s really effective at anything is anyone’s guess, but it’s easy to turn on and off and we default it on.

 

[denverpilot]

By the way I don’t care in the slightest if the person saying they needed to fly a different speed on approaches at high altitude airports admits that was ridiculously wrong or not.

I just want to kill that stupid OWT and make sure nobody reading the thread years from now gets similarly confused and this stupid concept lives on for another decade or two more.

The really funny part of this thread was sending a private note about this thread to another local CFI who does mountain training and he responded FIRST SENTENCE back with, “Was the author of that paper... X?” And he nailed it.

Apparently he’s been dealing with people misinterpreting that silly paper for as long as it’s been published and knew EXACTLY which paper and who wrote it. He knows the author too. Haha.

 

[SkyHog]

as I am sure you did as you were posting. Just don't here it often....if ever.

Two very common words in technology that aren’t common elsewhere: obfuscation and deprecation. Both correct. Both have specific meanings.

I probably use deprecate more often than almost any other word lately since so much crap changes so regularly. And I’m not even in tech anymore!

 

[denverpilot]

Two very common words in technology that aren’t common elsewhere: obfuscation and deprecation. Both correct. Both have specific meanings.

I probably use deprecate more often than almost any other word lately since so much crap changes so regularly. And I’m not even in tech anymore!

Deprecate in tech means, “We wrote such crap code, we’re abandoning it for new crap code, because we are sick of supporting our original crap code.” LOL.

 

[coloradobluesky]

What is going on is what is often called "secondary effects". To get the complete solution, you account for primary effects. Its off some, in this case a small amount. So he has "discovered" secondary effects. But if the secondary effects are in the "noise" (the +- error due to other things), the secondary effect doesnt matter. Airspeed indicators arent THAT accurate etc.

One example of this is F = MA (Force equals Mass times Acceleration). But this doesnt include the effect of relativity. Well relativity effects are miniscule for normal sized and normal experienced things on earth. Relativity effects can be ignored unless its high energy physics or something like that.

 

[denverpilot]

Not to mention the “secondary effect” of stupid math papers talking about two knot differences at 15,000 MSL, confusing some people into thinking they need to land faster in Denver than at home. Or that they “felt a difference” on a 3000’ runway at 2000 MSL after reading said paper. LOL.

 

[Clark1961]

Not to mention the “secondary effect” of stupid math papers talking about two knot differences at 15,000 MSL, confusing some people into thinking they need to land faster in Denver than at home. Or that they “felt a difference” on a 3000’ runway at 2000 MSL after reading said paper. LOL.

I’d phrase as: “they misinterpreted the difference they felt” instead of “felt a difference” since there are engine performance and TAS differences if it’s a hot day when they a doing their poorly controlled “experiments”.


I suppose I should be anxiously awaiting the AFM revision which incorporates the vital operational data presented in this thread. Nah, that’s not going to happen. Tspear went trolling with his post about calling someone to get airspeed and power settings then claimed insult when the silliness was exposed. He is the one who insulted with his attempted troll. Show more respect for the POA audience tspear.

 

[murphey]

Not to mention the “secondary effect” of stupid math papers talking about two knot differences at 15,000 MSL, confusing some people into thinking they need to land faster in Denver than at home. Or that they “felt a difference” on a 3000’ runway at 2000 MSL after reading said paper. LOL.

Let's be realistic....if tspear can tell the difference of 2 knots at any altitude, he's better than 99% of other pilots.

 

[Mtns2Skies]

Let's be realistic....if tspear can tell the difference of 2 knots at any altitude, he's better than 99% of other pilots.

I think "confirmation bias" describes his argument nicely.

 

[chartbundle]

I assume this comment was specific to the sightseeing in the Warrior? I fully intend to fly from Texas to Oregon early next year. That's gonna be difficult without flying over massive mountains unless I do a fairly big divert.

Obviously a Turbo 210 is a different matter. But interestingly it's not that big of a diversion, sure it seems like it but for the flight when I brought my Mooney home: KBAZ direct KCVO: 1488NM; KBAZ KLPC(California Coast) KCVO: 1778NM. At My speeds it was about 2 hours difference(10hrs vs 12hrs, neither I would have done in 1 day). Really much of the west can be flown at long distances at lower altitudes without much change in actual distances traveled(My KAPA to KCVO route similarly was about an hour longer than direct and no terrain above 10,000). This is not to say low altitudes, but lower than the 15000 feet of the highest peaks. Although in looking at it, even the direct route doesn't have much high terrain, I would have been south of most of it.

 

[Clark1961]

Obviously a Turbo 210 is a different matter. But interestingly it's not that big of a diversion, sure it seems like it but for the flight when I brought my Mooney home: KBAZ direct KCVO: 1488NM; KBAZ KLPC(California Coast) KCVO: 1778NM. At My speeds it was about 2 hours difference(10hrs vs 12hrs, neither I would have done in 1 day). Really much of the west can be flown at long distances at lower altitudes without much change in actual distances traveled(My KAPA to KCVO route similarly was about an hour longer than direct and no terrain above 10,000). This is not to say low altitudes, but lower than the 15000 feet of the highest peaks. Although in looking at it, even the direct route doesn't have much high terrain, I would have been south of most of it.

Not to mention that staying low helps avoid exposure to strong winds which can be brutal in the winter.

 

[denverpilot]

Let's be realistic....if tspear can tell the difference of 2 knots at any altitude, he's better than 99% of other pilots.

I’ve met a few who could do it. I won’t count myself in that crowd except on a REALLY good/lucky day.

There’s rumors that our friend @Everskyward could really “paint the needles on” but I’ve never had the honor of seeing it.

 

[Clark1961]

I’ve met a few who could do it. I won’t count myself in that crowd except on a REALLY good/lucky day.

There’s rumors that our friend @Everskyward could really “paint the needles on” but I’ve never had the honor of seeing it.

She can.

Me? I just cover up the panel, set power and hope for the best...

 

[denverpilot]

She can.

Me? I just cover up the panel, set power and hope for the best...

Cool.

I’m going to go give myself a hernia loading the 3000W generator into the car and taking it to the hangar because the 1000W struggles sometimes with our preheater. One less thing to worry about on Monday. Going to be cold. You people with electricity in your hangars make me jealous. LOL.

Go fly the plane around the patch and make sure the battery is behaving and charged up, too.

And take gas for the tug out there, it’s low.

And diesel for the big hangar heater.

And air compressor for the tires on the heater. And probably check the airplane and the tug too...

And... well whatever.

Winter. Bleh. I ain’t a badass hand propping a cub in snow like @Shepherd that’s for sure. But I might. If I had a Cub. LOL.

If I leave the 3000W at the hangar and we have a power outage at home, Karen will be motivated to let me buy that whole house genset and have it installed, too... LOL.

 

[SkyHog]

I assume this comment was specific to the sightseeing in the Warrior? I fully intend to fly from Texas to Oregon early next year. That's gonna be difficult without flying over massive mountains unless I do a fairly big divert.

Nope. Advice remains the same. Stay out of passes and you’ll be just as safe as you are at home without new knowledge requirements. Flying over mountains the same.

Now, doing both in the flight levels os obviously quite different. But if you’re at that altitude, you’re not “in a pass” anywhere in America, and you’re “over mountains” in the same way that flying at 1000ft AGL is flying over pedestrians.

 

[Clark1961]

Great fun. I'll check tire pressure tomorrow and plug in the crankcase heater. The charger/maintainer is always on. Might kick it up to high voltage setting. Won't bother with fuel until Monday morning. Oh, and my "tug" always has gas...