Backcountry Pilot • Idle at keypoint, or come in hanging by the prop?

Idle at keypoint, or come in hanging by the prop?

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Re: Idle at keypoint, or come in hanging by the prop?

Scolopax wrote:
In it's most rudimentary expression, the basics are:

Potential energy + kinetic energy = total flight energy

Potential energy is directly proportional to aircraft height above the surface or obstacle.

Kinetic energy is proportional to the square of velocity, that is - K.E. increases exponentially with in increase in airspeed. For this reason, an extra five knots results in a significant energy gain on the flying surfaces.

High and fast = lots of energy

Low and fast = some energy

High and slow = some energy

Low and slow = little energy

This is why takeoff and landing are the most critical phases of flight.

Most of us recommend building kinetic energy in ground effect on departure vs climbing out of it with no energy reserve (Vx). 500 ft of low level acceleration can result in efficiently gaining another 5-15 knots, which is definitely your friend should you need it. I think of it as having a little cash in the bank. Living paycheck to paycheck isn't ideal...

On landing, on the other hand, you will zero your potential energy once the plane is no longer supported by the wing. For this reason, extra potential or kinetic during approach can be undesirable, as it will increase your rollout energy. too little kinetic or potential energy can place you on earth prematurely, which is also undesirable.

Flying really is all about energy management. There is no perfect amount of energy to carry for every situation. This is where experience comes in. Thinking in terms of energy management is a very important process for a backcountry pilot do develop.

The FAA added Energy Management as a topic to the Airplane Flying Handbook in 2021 =D> I really don't understand how they avoided it for so long :lol:

Also, your fuel contains thermal potential that is converted to thrust through your thrust generating apparatus. If all goes well, you can use it to accumulate flight energy at any point during your flight, but it should be considered entirely differently from flight energy.

I hope that this basic explanation helps.



^^^^^ This is outstanding. ^^^^^

In looking for an instructor I would look for someone that teaches in way that fits with your style of learning. I happen to be a nerdy math geek and like formulas but some people just can't conceptualize an equation. For these students it is better to demonstrate it - for example - show the relationship between ground speed and bank angle for turn radius. More important than the formula - is applying the formula into your flying. Finding an instructor who you respect and who understands how you learn is what I think is most important. Obviously having a lot of experience being the other.



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Re: Idle at keypoint, or come in hanging by the prop?

Josh, agreed, you guys are the reason guys like me shouldn't even consider instruction.


TR, this may strike you odd, but I totally agree with you on many levels, where we get crossed up is not on what it takes to make the best aviator. * I think * I think where we get crossed up is on philosophy.

I think, no.... I know, that there are many people out there that just simply don't care why their airplane flies, what a carburetor is, or how to time a mag. They just want the magic carpet ride. On the other end of the spectrum is the true quintessential aviator, that gentlemen like yourself choose to be, and the rest of the flying world fit somewhere in-between this vast spectrum.
It's my opinion that when someone consciously chooses one of the sport pilot / recreational pilot classes, they are making a choice to make a compromise. The reasons for their compromise could be any number of things, but one very likely reason is because the type of flying they aspire to do may simply be a sunday lap around the block in their ultralight. In this scenario, they're attracted to the gift of flight, not the gift of scientific knowledge. I am also of the opinion that they can do that safely without knowing the laws, math, or physics of why it is happening. I also believe that the vast majority of GA flying would benefit more from developing appropriate motor skills and keeping them proficient than the knowledge portion.

It's not my position, nor desire to tell anyone how they should choose to live, love, or learn. But it's my opinion that instruction is just like another facet of flying. Choosing it to best suit your mission, will yield more smiles per mile, every time.

Take care, Rob

Oh oh....

Here's an oldie but goody for the naysayers of simple motor skills. And before the moderators can it for having nothing to do with backcountry flying, please realize the point behind the message...
Is Danny Macaskill formally educated? na... math, nope. Physics? nope. Outerlier? You bet. So are the young tikes just learning to ride on push bikes, which end of the spectrum will you aspire to lean your flying towards? And BTW, this is probably what launched him, and nowhere near his peak.
Enjoy
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Re: Idle at keypoint, or come in hanging by the prop?

I don't think that guy would have any problem with dynamic proactive rudder movement to bracket the centerline. Flying is a lot like riding a bike.
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Re: Idle at keypoint, or come in hanging by the prop?

Well said Rob and I believe we actually agree philosophically as well and here is why. If you re-read my post ref the instructor search, I believe the INSTRUCTOR should possess the mathematical knowledge base I referenced. I never stated the "student" required that level of knowledge. For the PPL level I expose students to formulas, however, the DLO is relationships. This goes up, that goes down type relationship. I stand my ground that a minimum of that understanding is required to safely operate. Now let's advance to the instructor applicant. I believe the instructor applicant must possess the knowledge base as I alluded to. Thats my opinion and I'm sticking to it. My only point to Varanger was that the INSTRUCTOR should possess that knowledge in my opinion. What resulted was a pile on as most responders assumed I meant the applicant/student required that full knowledge. I'm chuckling here, as what was meant as a helpful suggestion turned into a full blown response form a bunch of folks whom the comment was never intended for. Geeeez, this thread is so far off topic, I'm amazed Zane hasn't s piped in to call a knock it off! I suggest we stick a fork in this one and call it done. TR =D>
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Re: Idle at keypoint, or come in hanging by the prop?

What ?
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Re: Idle at keypoint, or come in hanging by the prop?

Rob wrote: It's my opinion that when someone consciously chooses one of the sport pilot / recreational pilot classes, they are making a choice to make a compromise. The reasons for their compromise could be any number of things, but one very likely reason is because the type of flying they aspire to do may simply be a sunday lap around the block in their ultralight. In this scenario, they're attracted to the gift of flight, not the gift of scientific knowledge.


Since you specified "very likely", I can't fault you. Even though I fly LSA I don't feel like this was directed at me. But it is funny I have the opposite impression, but that might be because GA is totally different here in Norway. I'd say that the majority of people who are into baccountry flying here, are SPL holders. There are many different reasons for it. Cost is a big one. 100LL is creeping up towards 14USD per gallon, while MOGAS is around 6USD per gallon. We also get road tax deduction, so maybe around 5-5.5.

But just finding a flight school that offers tail wheel training is close to impossible. One said that maybe they'll consider renting a Cub it if enough 500hr plus pilots are interested. It's pretty much all about emulating air line flying. Fly by the numbers. It's a skill and a science in itself, but when I want to go check out some of the old backcountry strips, then the road to get there gets too long and expensive.

I am fully aware of the envelope of an LSA being much smaller. But there is still more good days in a year than I will ever have the time to use. Another factor is that even though we have lots of mountains and forests, there's people living everywhere. You would be really hard pressed to find a place in Norway where you could walk for more than half a day before you stumble on a road or something.

Don't get me wrong. Under other circumstances, I'd go for PPL and get a proper Cub. But things being what they are, SPL is for many the best way to understand flying. But I wont say that the education to get the license is good enough. I was a bit surprised by how underwhelmed I felt when I got it myself. It just felt like a new step in solo training. There are (Maybe many, depending on where!) people who think they're good to go immediately.

This is a long and winded way of saying that I probably agree with you, and I am satisfied you said "very likely" and not "all". I'll take that as a caution and keep in mind that there might be a lackluster basic training I need to take responsibility for to mend myself.

TR wrote:Well said Rob and I believe we actually agree philosophically as well and here is why. If you re-read my post ref the instructor search, I believe the INSTRUCTOR should possess the mathematical knowledge base I referenced. I never stated the "student" required that level of knowledge. For the PPL level I expose students to formulas, however, the DLO is relationships. This goes up, that goes down type relationship. I stand my ground that a minimum of that understanding is required to safely operate. Now let's advance to the instructor applicant. I believe the instructor applicant must possess the knowledge base as I alluded to. Thats my opinion and I'm sticking to it. My only point to Varanger was that the INSTRUCTOR should possess that knowledge in my opinion. What resulted was a pile on as most responders assumed I meant the applicant/student required that full knowledge. I'm chuckling here, as what was meant as a helpful suggestion turned into a full blown response form a bunch of folks whom the comment was never intended for. Geeeez, this thread is so far off topic, I'm amazed Zane hasn't s piped in to call a knock it off! I suggest we stick a fork in this one and call it done. TR =D>


I read it alright, and there's been a few times at work where I haven't paid attention to what I am doing because I have been pondering this!

I get what you're saying. Knowing the maths behind drag increases with the square of speed is something I have thought about and felt gave me insight both when driving and sailing. I can feel it, but also kind of understand better what/why I feel. Don't know if that makes any sense... I haven't thought that much about it when flying, but it would make it more interesting. Maybe having an instructor who can explain this in a good way, not just repeat it, is something that would make me understand faster. It's not like it is in conflict with learning by feel. It's just two different approaches. I mean, you can't break a natural law even though you don't like maths.

EDIT: Regarding the digressions in this thread. Man, oh man am I happy for it. It is all connected, and it has given so much more meat on the bones on the question I first asked. It feels like it was ages ago. I knew there was a lot I didn't know, but now I know that it is a LOT, a lot. And I got some pointers on how to eat that elephant too. Maybe not all of it. Just having some bushflying elephant should be enough for me. I got work and family so I guess I am just a weekend warrior. Not wholly unprepared to make arrangements in my life to take my flying to another level, though... We'll see.

-V
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Re: Idle at keypoint, or come in hanging by the prop?

In the north on floats we always use a power on approach where possible. Lots of drag available. You took of at 100% power and then where cruising at 75% power so whats the chance of it quitting with a power on approach unless you run out of gas. Shock cooling the engine in a 500 ft power off descent is just setting the stage for a future power loss.
Personally and no doubt the engine would sooner you throw another stick on the fire than start blowing on the coals at the last minute.
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Re: Idle at keypoint, or come in hanging by the prop?

contactflying wrote:Patrick's near level attitude approach get you slow enough to sink enough that the need for power will bring the throttle into dynamic play. The throttle, when neither open nor closed, is the absolute best control for exact glide angle and rate of descent management. If the engine quits, you are high enough to pitch down a bit to lengthen the glide to the landing zone.


I'm just getting comfortable enough in my Maule M7 that I started working on Patrick's level wing approach this weekend as my short field has been doing exactly what folks are saying here. Come in and wait at the mercy of the float and miss my mark or put it down near the mark too hard and play rodeo for an extended roll out. I have a ton of practice to do but the method was as advertised. Easier on engine, better visibility, slow but good energy management, short flare with a shot of go-go juice and I was hitting my mark +/- 10 ft with decent touch downs. My timing sucks and comfort of not dropping the nose a bit to cheat the turns needs work but practice practice practice.
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Re: Idle at keypoint, or come in hanging by the prop?

As a crop duster and pipeline patrol pilot, I didn't get the advantage of the high approach. I forget the callsign, but the young pilot with the really nice Tri-Pacer who came by prefered very high. It was nice because we were much closer, and higher, when the apparent rate of closure of the numbers sped up past what appeared to be a brisk walk. Yes, easier than coming in from 200' as I was used to. At 200' AGL, we have to move the elevator and throttle (pitch up more and add more throttle) quickly when we appear to be closing much faster than a brisk walk. The deceleration timing is much easier with the steep glide angle Rob. I know, but why go up there?
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Re: Idle at keypoint, or come in hanging by the prop?

SugarGnarls, I am probably not understanding your last post. On final, we do not want to turn. We want to bracket the target, the numbers, with dynamic proactive rudder. Aileron, with adverse yaw, is a big distraction here. Especially on short final when we are either decelerating when the apparent rate speeds up or when we flair. We don't need the distraction of incorrect yaw when we are working the "all slowed up and ready to squat" bit.
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Re: Idle at keypoint, or come in hanging by the prop?

@contactflying Nope, sorry, I meant the downwind to base and base to final turns. Patrick's method is (if flying a traditional pattern) being slowed to mid white arc by mid-downwind and all slowed up and level wings abeam the numbers and keeping the wings level, or whatever the AOA for that aircraft is throughout the rest of sequence.
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Re: Idle at keypoint, or come in hanging by the prop?

Yes, that makes sense. Right at the bottom, just before the flair, well into ground effect, realize that critical AOA out of ground effect is different than in ground effect. Using the really well made gear build up modifications is good Navy technology, but could cause a bounce in a Cessna or Piper or Maule, etc. I teach 1.3 to quarter mile final, slow to sink and need for dynamic throttle power for stable glide slope (probably about Patrick's AOA) and then watch to keep (with elevator) the apparent brisk walk rate of closure with the numbers the same as it appears further back, and flair to three point. The flair to three point part is all slower than Vso or critical AOA. The wing in ground effect does not stall at the same airspeed or AOA. Hover taxi down the runway proves the energy value of prop blast over the inner portion of the wing and all the tail and of ground effect. Hover taxi speed and AOA would result in stall if out of ground effect.

So even with Patrick's very good technique, getting into three-point attitude all slowed up and ready to squat, ala Wolfgang, is still possible for normal geared pilots. Wolfgang didn't know about modern STOL gear or he would have said, all slowed up and ready to squat softly. As Patrick says, a little blast of throttle at the bottom is fine as well.
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Re: Idle at keypoint, or come in hanging by the prop?

SugarNarls, I assume that having to close throttle before touchdown with Patrick's AOA landing would indicate too little AOA and too much airspeed. It that the case? With the deceleration to maintain the apparent brisk walk rate of closure with the numbers, having to close the throttle means too much airspeed. With either, however, we need to work down to that deceleration airspeed and AOA. Everyone lands too fast until mastering either technique, I think. It seems, from video, that most STOL contest guys use Patrick's technique. But, those coming in low and slow use apparent rate. I also use the latter as crop duster and pipeline patrol pilot, but have found that the steeper the approach the easier is the apparent brisk walk rate of closure approach. This is because the speed up of the apparent rate of closure is more gentle and gives the pilot a bit more time to react with elevator. Good stuff, either approach.
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Re: Idle at keypoint, or come in hanging by the prop?

The AOA approach is working, and I'm not closing the throttle but giving it a quick shot to arrest descent just before touchdown. Need to keep working timing but it's working well.

The odd part, is holding the "level" AOA in downwind to base, and base to final turns. It feels odd and my instinct is still to drop the nose for airspeed during those turns which is counterproductive because then I am too fast on short final and closing the throttle, losing some of the dynamic throttle abilities and being "behind" the airplane again. I think it's just retraining the brain off the training schools 80 kts downwind, 70 kits base, 60 kts short final I was taught.

Practice, practice, practice....well, after the exhaust welds that snapped off are fixed.
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Re: Idle at keypoint, or come in hanging by the prop?

I see no need for level AOA on downwind or even base if we are following someone who makes a long downwind. Or, if allowing the nose to go down as designed, we can use elevator to return to level AOA on final. The huge advantage of the apparent brisk walk rate of closure, the deceleration on short final, is that we don't have to be dangerously slow when maneuvering say in a tight and crooked valley. Also, at the big airport with a strong crosswind, we can angle across from the downwind corner to the upwind large airplane touchdown zone square. Gusts, with Patrick's technique or mine, require dynamic throttle. With a strong sink, full throttle and then adjust. With a strong balloon, close throttle and then adjust. With minor gusts, just dynamic throttle. Just as when rudder only is exactly bracketing the centerline, dynamic throttle can exactly bracket the desired glide angle all the way down. Any technique that is dependent on perfectly calm air is not a good default technique. Default techniques are the ones that develop muscle memory, for good or bad. Muscle memory of sink to bring throttle into play, deceleration by keeping the apparent rate of closure from appearing to speed up, and flair to touchdown slowly and softly on the numbers every time develops the muscle memory useful in all conditions, especially the crosswind that would cause us to run out of rudder using the centerline. The crab and kick straight for touchdown is hard on the gear and can result in loss of control.

I like Patrick's understanding of the danger of lots more than Vso airspeed on landing. The level AOA, however, does not consider the difference in energy available in ground effect. Either Vso or level AOA will create too much potential and kinetic energy to stay at the same glide angle to touchdown. Some float will result unless we decelerate somewhere on the approach coming from out of ground effect to into ground effect to into low ground effect.

Using the apparent speed up in rate of closure on very short final to further decelerate and thus maintain the apparent brisk walk rate of closure with the numbers is what mitigates, or if done expertly eliminates, float. We are actually using dynamic throttle to gently let ourselves down to the surface in ground effect in no wind, light wind, crosswind, downwind, and very strong crosswind with some of the crosswind component taken out by angling across the runway. As a default landing technique, it will develop good slow flight muscle memory for dynamic proactive rudder, dynamic throttle, dynamic elevator, and zero aileron except to set bank angle for crosswind. And hover taxi, basically in the same AOA configuration, will give us many more iterations of each control usage except aileron because we now want to crab wings level. It hurts the mind a bit, but crab wings level is still a dynamic proactive rudder technique to direct butt to target as accurately as when we are keeping the centerline between our legs in a no crosswind condition.
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Re: Idle at keypoint, or come in hanging by the prop?

I have followed this thread with keen interest, having recently bought a plane and now visiting more "interesting" grass strips and such here in Wisconsin. Does anyone have any tips for an outlier like me? I have a Taylorcraft and NO flaps, so my landings are always different than all the ones I did as a student in those 152's and 172's. Approach at 60, kill the power abeam the numbers, ride it down at idle around to base and then final, then start flaring for just a hair below 55mph, fiddle with the power a bit to nail it, flare, and wait....and wait...and wait. What usually happens is the plane starts to sink below what I consider the glidepath just as you make that turn to final...I add a little power and then my brain says: "wait...now that I'm all lined-up nice and pretty, perhaps I'm a bit HIGH now"...followed by the inevitable side-slip (which alarms the passenger) and 'restabilization' to get lined-up once it looks good. The lack of flaps is always a silly dance it seems. I only have 20 hrs in my new-to-me T'craft, but some tips from some Taylorcraft guys would be awesome!
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Re: Idle at keypoint, or come in hanging by the prop?

Fiddling with the power to nail the glide angle and rate of descent you mentioned is the key to getting in near the beginning of the strip. Practice slow flight at altitude to find out how more sink stabilized by more power gives you the opportunity to add more power with less airspeed and quicker reaction to change in glide angle with power change. Also this will convince you that you don't need, don't want, aileron to direct your course exactly to a target with dynamic proactive rudder. No aileron, no bank, no wing wagging to find the centerline. Bracket the target with rudder movement. On long runways at six inch to one foot above the runway in the float, find out how much slower you can fly in ground effect with pitch/power...what I call hover taxi. If you read about Wolfgang's stall down on page 302 and 304 of Stick and Rudder, you will see a soft field that can be made on the beginning of the runway using apparent rate of closure to slow up in ground effect before you get there.

The aileron is way out on that long wing. It is not your friend, except to hold a stable bank in a side slip into a crosswind.

With no flap or less effective than Cessna 40 degree flaps, power/pitch is the only way to get in reasonably short or over trees.
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