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Posted

IF you are flying level or on a fixed approach angle, your speed is controlled by POWER . It's also a good thing to use if you get near the stall. and have no height to spare. The elevator controls the wing AoA and causes the stall. Many stalls are a reflex action done without proper consideration of the circumstances the plane is in. ie Lack of situational awareness. (STALL margin etc).   Nev

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Posted

"IF you are flying level or on a fixed approach angle, your speed is controlled by POWER ........"

 

Again. All very good as long as your engine is delivering power. Far better to become proficient in the glide approach & landing.

 

What you are promoting was just how I was trained in GA (fortunately also had a lot of glide approach/landing as well). My RAA conversion emphasised the glide approach and I am very glad of it.

 

Being competent in the glide approach makes for a better more confident pilot, much less likely to "drag' the aircraft in to landing, on power. Power is still there, if needed, when everything comes together , its not.

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Posted (edited)

Of Course the RAAus teach glide approaches. We all do forced landing practice which gives you no choice about power  In a forced landing you aim for about 1/3rd down the runway just to make sure you make it.

  The philosophy si "It's Better to hit the far fence at running speed than hit the near one at flying speed.. IF you have a very limited runway length using power will permit a more accurate RoD and speed at the threshold and flare point. On a cross country you don't have glide reachable aerodromes all along the way and idling motors often stop because they are set too slow.   Nev

Edited by facthunter
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Posted

That's VERY helpful. NOT. In flying , there are options and deciding which one is BEST, WHEN is managing the situation optimally.  Nev.

Posted

Fair go Nev: Your earlier advice, regarding power on approach to landing, was not qualified in any way. All I have done is suggest an alternative: the glide approach, as this usually considered the more difficult, of the two skills but has the advantage of being the one every pilot needs to be proficient at, when the noise stops.

 

Sure, every approach to landing presents as a dynamic range of challenges, which must be met from the pilots skill set, to acheive a successful touchdown. We are all prone to developing habits - I try for a glide approach every time. On my old plane, (10+ years of flying) I was successful perhaps 90% of the time. On my new, plane very diffrent characteristics, the  percentage is probably reversed ie 10% but getting better the more I practice.

 

I would advocate for every small aircraft pilot to make the glide approach his/her prefered  technique - anyone can use power, as a backup, I often do.

 

Note: I consider the glide approach to have failed, if I need to resort to power, to acheive a safe landing.

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Posted

Tumut's 35 runway has an 8m deep erosion gulley on the threshold. No one wants to land short! However we do practice full glide approaches all the time. Judging final turn at around 500ft means that one can hit the piano keys mostly without adding power. You also have the option to add more flap or slip height off. All very character building and it increases the odds of not coming to grief. 😂 Don

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Posted (edited)
34 minutes ago, Methusala said:

Tumut's 35 runway has an 8m deep erosion gulley on the threshold. No one wants to land short! However we do practice full glide approaches all the time. Judging final turn at around 500ft means that one can hit the piano keys mostly without adding power. You also have the option to add more flap or slip height off. All very character building and it increases the odds of not coming to grief. 😂 Don

you need to put a jabiru in your profile. you haven't owned that thruster for a while. it belongs to another member of the group.😃

Edited by BrendAn
Posted (edited)

The glide thing was more with TWO stroke power which was far more likely to let you down. Most engine failures are at  the higher power settings in the take off phase particularly. Cruise is normally at about 75% power, still a relatively high figure.. In  gusty conditions using a variable power is the only way to avoid large speed fluctuations. Putting the nose down is not a quick response and you don't want wild variations of attitude near the ground particularly. Precautionary approaches are done with power and a reduced stall margin. A go around from a "Power active" approach is more spontaneous, and the engine is less likely to falter.  Nev

Edited by facthunter
typo
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Posted
30 minutes ago, BrendAn said:

you need to put a jabiru in your profile. you haven't owned that thruster for a while. it belongs to another member of the group.😃

Hey Brendan, I'm sentimental about my Thruster, Don

Posted

My first ever Ultralite in 1986 at a Mangalore Airshow with plenty of watchers. I didn't get a photo.. Some aeroplanes do make you sentiMENTAL.. Julius Ceasar never had a chariot like any of them? Nev

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Posted

"Most engine failures are at  the higher power settings in the take off phase particularly. "

Student pilots are repeatedly warned about the above and encouraged to have a plan for when it happens (land straight ahead being the most common advice).

 

Less emphasized, is engine failure partial/total in the circuit, which can occur during/after the change from cruise to idle/low power. Multitude of possibilities, Carby ICE  being one of the lead offenders.

 

With the latter, if you have configured the aircraft & your mental self, for a gide approach, the chances are you will make the airfield/landing. On the other hand, if it is all power, you are relying on,  chances are you will land short/crash.

 

"In  gusty conditions using a variable power is the only way to avoid large speed fluctuations. "

Of course this should be part of every qualified pilots skill set. This does not mean that in less taxing wind conditions, the glide approach can not be tried.

 

"Precautionary approaches are done with power and a reduced stall margin. A go around from a "Power active" approach is more spontaneous, and the engine is less likely to falter."

Agree however the majority of landings are not short field.

 

Sighting specific conditions against, does not address my contention that pilots should aspire to glide approaches, whenever conditions allow.

 

 

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Posted

" Glide approach " ,

Does that mean ' engine out ' & gliding. 

" carby icing " .

Cannot happen without "  moisture in the air " !  

According to my ' test paper ' ,

My failure to understand,  tests are not for a particular area of flying .

spacesailor

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Posted
16 minutes ago, spacesailor said:

Cannot happen without "  moisture in the air " !  

There's pretty much always moisture in the air in Australia. That's what appears on the outside of a cold drink.

If it gets very cold the amount of moisture in the air is significantly reduced.

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Posted
10 hours ago, facthunter said:

IF you are flying level or on a fixed approach angle, your speed is controlled by POWER

Speed is always controlled by angle of attack (at constant G). Power does not appear in the lift equation.

 

But sometimes e.g. on a precision glide path it is easier to change power first, and then change the AOA gradually to change the speed. This avoids significant changes in flight path.

 

The problem, and what makes this more difficult, is that changing speed also changes drag and therefor power required. So you might need more power adjustments as the speed changes.

 

If you don't have to follow a precision glide path it is easier to set the speed first and then adjust the power. If the speed is not fluctuating, the power required to overcome drag stays the same so you don't end up chasing it. This is more pronounced at slower i.e. landing speeds.

 

In cruise, you set the power and then adjust the trim i.e. angle of attack to give a speed where you are not climbing or descending.

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Posted

Temperature was / is not mentioned. 

Only " moisture in the air " .

I failed to understand that logic in reference to Raaus ," piston engined / single propeller/ 10,000 foot ceiling aircraft .

spacesailor

 

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Posted
8 minutes ago, spacesailor said:

Temperature was / is not mentioned. 

Only " moisture in the air " .

I failed to understand that logic in reference to Raaus ," piston engined / single propeller/ 10,000 foot ceiling aircraft

The carburettor creates the temperature drop. The drop in pressure across a closed throttle plus the evaporation of the fuel significantly drops the temperature of the air downstream of the carb - by as much as 10, 20 maybe even 30C.

So downstream of the carb you have water condensing out of the air, and possibly surface temperatures below freezing.

So all you need is moisture in the air (humidity, not visible moisture) - the carb does the rest.

 

https://www.casa.gov.au/sites/default/files/2022-10/carburettor-icing-probability-chart.pdf

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Posted

Aro the last line of your previous post is not correct. On reaching your cruise level you first level off and let the plane  accelerate to the cruise speed then set cruise power and trim out stick forces.   Nev

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Posted
12 hours ago, spacesailor said:

" Glide approach " ,

Does that mean ' engine out ' & gliding. 

" carby icing " .

Cannot happen without "  moisture in the air " !  

According to my ' test paper ' ,

My failure to understand,  tests are not for a particular area of flying .

spacesailor

In the context of my statements, I would define glide approach as one where power is not used to control descent rate. I think it is generally accepted that deliberately stopping your engine (in flight) is ill advised, when practising engine out/low power scenarios.

 

The aim of my comments on this matter are to encourage pilots to achieve & maintain their skills in glide approaches. They will need this skill when the engine fails to deliver sufficient thrust to sustain flight. The simplest way to keep these skills "sharp"/instinctive are to try for a glide approach on every landing.

 

My GA training emphasised power on approaches - great! as long as the engine is operating correctly.

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Posted (edited)
On 11/02/2024 at 9:15 AM, Methusala said:

Good  landings begin with a good approach. Perhaps Nev could say a few things about stabilised approaches in airline flying. Don

PA28 : I'd shot a few approaches after lunch yesterday on a warm 32degC day. Late summer, the ground is warm now even at 5am.

There's not much more ' un stabilized approach  ' then  the glide in the bumps  over bare paddocks in the summer afternoon. I think its a good challenge.

 

Last approach was a glide approach in the sinks and the bumps. I flew low over a big freshly burned/tilled?/ cleaned brown patch , hoping to get a bit of assistance, as I was a bit low..... and got a sink. Was flapless at the time since flaps only would have hastened my descent, so getting a bit slow, put power on a bit, then resumed glide the last 100m to the runway midfield, over runway, all the flaps out in one go,  decending turn to line it  up, as long as I keep my airspeed up, all is good. .   and plonk. geez I know this girl now. But glides in the bumps are challenging.

 

The biggest driver of my landing performance is currency.  More so than fatigue I think. At least Weekly flying drives competence/currency/ confidence.  And I mean not going out at 7am, but going out when its a little challenging...  (if that's what you want) 

 

Edited by RFguy
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Posted
13 minutes ago, facthunter said:

On reaching your cruise level you first level off and let the plane  accelerate to the cruise speed then set cruise power and trim out stick forces.

That's technique (how you do it) rather than a description of the effect. The increase in stick forces as you are accelerating is the adjustment to the angle of attack to increase speed rather than climb. When you trim doesn't change what is actually happening.

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Posted

Strongly disagree. You don't get speed in cruise by pitch changes and mentioning trim only confuses what's happening ,Trim only relieves stick forces. You  accelerate due to leaving climb power on for long enough..   Nev.

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Posted

I nose over,  (end climb)  then let the plane accelerate to desired cruise speed, reduce throttle as necessary, and then trim for zero stick forces. 

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