Question: Behaviour of Laminar Flow Wings
Thread Starter
I must be showing my complete naivety and inexperience.
Tinpis, the instructor who endorsed me would have agreed with your views. It's an aeroplane - fly it. Yes, I can do that, exactly as according to the POH. I think you might like to reconsider your comment re "kiddy car" aeroplanes.
Ratty, of course if you need power you are going to firewall the throttle, my point is that it is disconcerting to your ever trusting passengers to do it on final, let alone a go around, although I would never let my pax's sentiments ( Blond Art Teacher - enough said) get in the way of self preservation.
"Stable approach" yes - speed gradually coming back as you approach the threshold, arriving at V ref. or whatever. The Laminar flow wing has different drag characteristics - the drag builds up much faster than a C172 or Warrior. The point that has been made to me is that you should fly it fast and let the natural drag of the Laminar flow wing at lower speeds slow you up much later in the approach than with a Cessna or Warrior.
The point I am trying to understand, is what is the safest, cheapest and most elegant way to land this particular aircraft. There seem to be two schools of thought in this thread:
(a) Who gives a ****?
(b) Follow the POH exactly.
Translation: I can land anything - but what is the best way to do so? It isn't always in the POH. Bushy, I think has agreed with me.
I would also like to suggest that some of the woes of students are a result of the differing opinions of instructors and pilots around the country - as evidenced by comments on this thread.
The method I've been shown takes advantage of the quick drag build up as you slow to give a good landing and maintains enough energy in the aircraft to give a decent margin of safety. As I've said, doing this in a C172 or Warrior would see you float the length of the runway.
Tinpis, the instructor who endorsed me would have agreed with your views. It's an aeroplane - fly it. Yes, I can do that, exactly as according to the POH. I think you might like to reconsider your comment re "kiddy car" aeroplanes.
Ratty, of course if you need power you are going to firewall the throttle, my point is that it is disconcerting to your ever trusting passengers to do it on final, let alone a go around, although I would never let my pax's sentiments ( Blond Art Teacher - enough said) get in the way of self preservation.
"Stable approach" yes - speed gradually coming back as you approach the threshold, arriving at V ref. or whatever. The Laminar flow wing has different drag characteristics - the drag builds up much faster than a C172 or Warrior. The point that has been made to me is that you should fly it fast and let the natural drag of the Laminar flow wing at lower speeds slow you up much later in the approach than with a Cessna or Warrior.
The point I am trying to understand, is what is the safest, cheapest and most elegant way to land this particular aircraft. There seem to be two schools of thought in this thread:
(a) Who gives a ****?
(b) Follow the POH exactly.
Translation: I can land anything - but what is the best way to do so? It isn't always in the POH. Bushy, I think has agreed with me.
I would also like to suggest that some of the woes of students are a result of the differing opinions of instructors and pilots around the country - as evidenced by comments on this thread.
The method I've been shown takes advantage of the quick drag build up as you slow to give a good landing and maintains enough energy in the aircraft to give a decent margin of safety. As I've said, doing this in a C172 or Warrior would see you float the length of the runway.
Sunfish, I'm not going to try telling you how to land the Lance but you might learn more if you stop bringing laminar flow aerofoils into the discussion. The Warrior has exactly the same aerofoil section and I don't recall you raising these points when you were flying it.
Most people look at the standard graphs of two-dimensional profile drag coefficient plotted against anagle of attack. However, aircraft behaviour relates to "real" numbers. If you take the trouble to plot total aircraft drag against airspeed for the Lance, maybe even do the simple sum of replacing the laminar flow aerofoil with the one used in the 172 you'll see what I mean.
The main parameter in drag rise of the airplane itself in this situation is span loading i.e. weight divided by wing area. i.e. the heavier the airplane the greater the induced drag. Again, most people are familiar with the induced drag equation as a coefficient. Expressing it in drag as a force, it varies with weight squared. See more at:
http://selair.selkirk.bc.ca/aerodyna...rag/Page7.html
The other significant parameter is the propeller - closing the throttle of a C/S prop with a six cylinder makes a big difference in thrust (or is it drag) compared to the fixed pitch propeller of the 172 or Warrior. Its a very effective brake.
Most people look at the standard graphs of two-dimensional profile drag coefficient plotted against anagle of attack. However, aircraft behaviour relates to "real" numbers. If you take the trouble to plot total aircraft drag against airspeed for the Lance, maybe even do the simple sum of replacing the laminar flow aerofoil with the one used in the 172 you'll see what I mean.
The main parameter in drag rise of the airplane itself in this situation is span loading i.e. weight divided by wing area. i.e. the heavier the airplane the greater the induced drag. Again, most people are familiar with the induced drag equation as a coefficient. Expressing it in drag as a force, it varies with weight squared. See more at:
http://selair.selkirk.bc.ca/aerodyna...rag/Page7.html
The other significant parameter is the propeller - closing the throttle of a C/S prop with a six cylinder makes a big difference in thrust (or is it drag) compared to the fixed pitch propeller of the 172 or Warrior. Its a very effective brake.
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I was going to write "in all my PA18/25/28/32/38 and C150/152/172/180/182/185/206/210 flying, I have never thought "now this one has laminar flow aerofoil so I'll approach fast and allow the
natural drag characteristics of the aerofoil to slow me down as I come over the fence"".
and then the penny finally dropped ......
This is a wind-up!
No one could actually believe this crap.
Man, you got us good!
BC
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Or sunfish is looking for an excuse to post whore after being put on warning for posting in the areas for CPL's and ATPL's when there is a PPL forum to discuss this type of chud that a paid pilot doesnt give a second hoot about 
sorry Sunfish.....
sorry Sunfish.....
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Gentlemen and Ladies,
Well, my instructor did give me a briefing on the laminar flow wing when we were discussing stalls. Being the diligent student pilot that I am, I actually wrote down his briefing notes!! Here's some of it on the laminar flow wing;
0. Laminar flow aerofoils are designed for better aerodynamic efficiency at faster speeds.
1. Laminar flow aerofoil is symmetrical so that the thickest part of the wing (max camber) is in the middle part of the aerofoil. (Conventional wings have the max camber closer to the leading edge).
2. Since max camber is further down the aerofoil (halfway down the chordline) compared with a conventional aerofoil, the transition point and separation point is further along the aerofoil as well.
3. As a result, smooth laminar flow occurs over a greater surface area of the aerofoil compared with a conventional aerofoil and therefore producing less drag.
4. Thus there is less turbulent wake (ie drag) over the surfaces of a laminar flow wing compared with a conventional wing.
5. Therefore laminar flow wings are better suited for high speeds due to less form drag being produced compared with conventional aerofoils.
6. The problem is that laminar flow wings are designed to be optimal at high speeds, so when in low speed flight, the aerodynamics sucks.
7. At or near the stall, the transition point moves forward along the aerofoil quicker than a conventional wing so laminar aerofoil flies like a brick at low speeds due to more turbulent wake over the aerofoil surfaces.
Ok, well, that's all I have so I guess I can understand what Mr Solarfish in on about (or at least his instructor) in wanting to come into land faster than usual.
Suffice to say that I didn't fly much in laminar flow wing aircraft.
Give me a C-152-172 any day, mate,
Well, my instructor did give me a briefing on the laminar flow wing when we were discussing stalls. Being the diligent student pilot that I am, I actually wrote down his briefing notes!! Here's some of it on the laminar flow wing;
0. Laminar flow aerofoils are designed for better aerodynamic efficiency at faster speeds.
1. Laminar flow aerofoil is symmetrical so that the thickest part of the wing (max camber) is in the middle part of the aerofoil. (Conventional wings have the max camber closer to the leading edge).
2. Since max camber is further down the aerofoil (halfway down the chordline) compared with a conventional aerofoil, the transition point and separation point is further along the aerofoil as well.
3. As a result, smooth laminar flow occurs over a greater surface area of the aerofoil compared with a conventional aerofoil and therefore producing less drag.
4. Thus there is less turbulent wake (ie drag) over the surfaces of a laminar flow wing compared with a conventional wing.
5. Therefore laminar flow wings are better suited for high speeds due to less form drag being produced compared with conventional aerofoils.
6. The problem is that laminar flow wings are designed to be optimal at high speeds, so when in low speed flight, the aerodynamics sucks.
7. At or near the stall, the transition point moves forward along the aerofoil quicker than a conventional wing so laminar aerofoil flies like a brick at low speeds due to more turbulent wake over the aerofoil surfaces.
Ok, well, that's all I have so I guess I can understand what Mr Solarfish in on about (or at least his instructor) in wanting to come into land faster than usual.
Suffice to say that I didn't fly much in laminar flow wing aircraft.
Give me a C-152-172 any day, mate,
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Flying down final "just below" max flap extension speed is probably not what the chief pilot wants to hear you're doing to the machine....
Yes, it is permissible and does not exceed a limitation but it is not the designer's intent. It adds to airframe stresses and will eventually result in additional maintenance expense, if done constantly.
Power changes on this relatively small, normally aspirated (I presume?) engine are not something to worry about, unless you're talking constant, large slam throttle movements.
Why not fly a normal slope at the approach speed? The end result is still a touchdown at the correct speed and you don't need to worry (as much) about finishing up in the undershoot if it all goes wrong.
This all sounds really dodgy. What is the true motivation for this thread?
Yes, it is permissible and does not exceed a limitation but it is not the designer's intent. It adds to airframe stresses and will eventually result in additional maintenance expense, if done constantly.
Power changes on this relatively small, normally aspirated (I presume?) engine are not something to worry about, unless you're talking constant, large slam throttle movements.
This all sounds really dodgy. What is the true motivation for this thread?
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Read and adhere to the POH
Gday Sunny
I haven’t bothered to read through most of the posts, the only noticeable performance difference between the wing profiles is the stall, the laminar stall is little more pronounced, as for flying the approach at a higher speed find another instructor, coz I reckon the piper test pilots would have forgotten more about flying Lances than that wacker will ever know.
Cheers Q
I haven’t bothered to read through most of the posts, the only noticeable performance difference between the wing profiles is the stall, the laminar stall is little more pronounced, as for flying the approach at a higher speed find another instructor, coz I reckon the piper test pilots would have forgotten more about flying Lances than that wacker will ever know.
Cheers Q
Thread Starter
DjPil, thank you for your advice. According to "The Incomplete Guide to Wing Sections" it is indeed the same section and I have obviously been barking up the wrong tree regarding the drag build up. The approach speed demonstrated and practiced is on the fast side of the POH recommendation, but within the limits, and the drag increase as you close the throttle is very pronounced, at least to me, much more so than an Arrow.
You would know and I'm sure approve of the instructor involved, who has suggested that it would now be rewarding for me to concentrate on precision in my flying and that with heavier aircraft and a trusting friend or two on board, that a little finesse in the handling of the aircraft and powerplant would be a good thing, both for friends nerves and larger powerplants.
I take comfort from the constructive comments here, especially yours, Chimbu and Bushy. As a curious person, I like to know why I'm advised to do things a certain way and whats behind the POH and recommended procedures against the day I run into uncharted territory.
As for the others, critical of me for having the temerity to even raise what to me was an issue, I'd like to remind you that there is considerable and ongoing debate on Pprune and elsewhere about training standards, something that has even got CASA's attention. Your posts demonstrate that reform is long overdue.
You would know and I'm sure approve of the instructor involved, who has suggested that it would now be rewarding for me to concentrate on precision in my flying and that with heavier aircraft and a trusting friend or two on board, that a little finesse in the handling of the aircraft and powerplant would be a good thing, both for friends nerves and larger powerplants.
I take comfort from the constructive comments here, especially yours, Chimbu and Bushy. As a curious person, I like to know why I'm advised to do things a certain way and whats behind the POH and recommended procedures against the day I run into uncharted territory.
As for the others, critical of me for having the temerity to even raise what to me was an issue, I'd like to remind you that there is considerable and ongoing debate on Pprune and elsewhere about training standards, something that has even got CASA's attention. Your posts demonstrate that reform is long overdue.
Silly Old Git
I have had a re-thunk and ...yup its still a kiddy-car hairyplane 
Seriously dude if you want to fly a Piper get a Cub and a good OLD TIME instructor and learn to put that thing where you want it from BOTH seats and I bet you will go and kick that LANCE in the nuts.
Seriously dude if you want to fly a Piper get a Cub and a good OLD TIME instructor and learn to put that thing where you want it from BOTH seats and I bet you will go and kick that LANCE in the nuts.
Last edited by tinpis; 1st Dec 2006 at 20:18.
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And as for flight training standards, you did say you were taught by "a highly experienced and respected instructor to land it"
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Fuss and bother?
I don't know what all the fuss is about.
Max flap speed in the lance is 109 kts.
The approach speed from the landing chart is 75 kts (what I call "target threshold speed")
Stall speed is 62 kts, and 1.3Vs is 81 kts.
So what is wrong with an approach at 90 kts, slowing to 75 at the threshold?
The POH has accurate data (they would be sued right off the planet if it was not). The POH should take precedence over those "uniquely Australian" old wives tales that are so common.
Max flap speed in the lance is 109 kts.
The approach speed from the landing chart is 75 kts (what I call "target threshold speed")
Stall speed is 62 kts, and 1.3Vs is 81 kts.
So what is wrong with an approach at 90 kts, slowing to 75 at the threshold?
The POH has accurate data (they would be sued right off the planet if it was not). The POH should take precedence over those "uniquely Australian" old wives tales that are so common.
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