Airbourne prematurely
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Pilot DAR gives good advice; much of what preceeds his post in this thread is not so good, and some is awful. Fly attitude, use the flaps as Mr Cessna intended them to be used.. and what's this 'rotate speed' all about? It's a 172 FFS not a 747! When it's ready to fly, it'll fly!
Are today's studes actually taught 'rotate speed' in SEPs? If so, I despair!
Are today's studes actually taught 'rotate speed' in SEPs? If so, I despair!
Last edited by Shaggy Sheep Driver; 30th Jul 2012 at 16:47.
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Are today's studes actually taught 'rotate speed' in SEPs? If so, I despair!
The main runway at my airfield has large trees at the end so you don't want to hang around on the ground too long. I was therefore taught to 'rotate' as soon as safe to do so, i.e. 55kts, build up speed in ground effect, then climb out at optimum rate.
Obviously not such an issue if you have 2km of tarmac in front of you, and you can sit around all day waiting for the plane to decide when it's ready to fly!!
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Ds3, your 'rotate speed' will come up on the ASI long after the plane has told you it wants to fly. If you have been taught to have the sensitivity in your hands to hear it, that is.
Or you can simply 'fly by numbers' and sit there staring at the ASI if you have the luxury of miles of tarmac stretching in front of you, and if you have no ambitions to be a pilot rather than an aeroplane driver.
Or you can simply 'fly by numbers' and sit there staring at the ASI if you have the luxury of miles of tarmac stretching in front of you, and if you have no ambitions to be a pilot rather than an aeroplane driver.
Last edited by Shaggy Sheep Driver; 30th Jul 2012 at 18:07.
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Don't really understand your post, you seem to be agreeing with me in part but also suggesting an HR200 will tell you it wants to fly long before 55kts.
Obviously it's dependant on circumstances, however the example I used was specific to my experience of getting the Robin up when two up with fuel, off a grass strip with trees at the end. In that example, the minimum IAS it'll sustain flight in ground effect is at around 55kts, certainly not well before, and it requires a little extra backwards movement on the stick to lift up, hence use of the term 'rotate'.
You cannot afford to hang around on the ground too long due to the trees, so it's quite the opposite of being an 'aeroplane driver' having miles of tarmac to stare at the ASI, it's using the best method to get the plane up to speed in as short a distance as possible.
Not sure you what you mean about hearing through your hands though?
Obviously it's dependant on circumstances, however the example I used was specific to my experience of getting the Robin up when two up with fuel, off a grass strip with trees at the end. In that example, the minimum IAS it'll sustain flight in ground effect is at around 55kts, certainly not well before, and it requires a little extra backwards movement on the stick to lift up, hence use of the term 'rotate'.
You cannot afford to hang around on the ground too long due to the trees, so it's quite the opposite of being an 'aeroplane driver' having miles of tarmac to stare at the ASI, it's using the best method to get the plane up to speed in as short a distance as possible.
Not sure you what you mean about hearing through your hands though?
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taxi all getting a bit heated as usual.
Best thing is to go and find an instructor who likes this sort of thing. Personally I love doing this sort of training and it used to be my suggestion for the hour flight. I was lucky having Dornoch just up the road to go and use.
If you give a ruff area somebody who likes doing this sort of training might send you a pm.
Its not actually as difficult or as "dodgy" as it sounds on here.
Best thing is to go and find an instructor who likes this sort of thing. Personally I love doing this sort of training and it used to be my suggestion for the hour flight. I was lucky having Dornoch just up the road to go and use.
If you give a ruff area somebody who likes doing this sort of training might send you a pm.
Its not actually as difficult or as "dodgy" as it sounds on here.
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As for the cruise on the old ones. More like 120mph. Cessna are a bit more truthful these days.
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Not sure you what you mean about hearing through your hands though?
Some aeroplanes are more 'talkative' than others. To get our Chipmunk off a short muddy field I'd hoink it into the air at the earliest possible point, way before it's ready to fly away, way on the back of the drag curve. Holdng the aeroplane level just above the surface one can 'feel' the CP creeping forward as the speed builds until the aeroplane says "OK, I'm good to go now. You can climb away". And I do.
At no point do I look at the ASI (except to check it's 'alive' and working). It's all done through feel. My eyes are outside assessing runway remaining before the hedge, and the rate we're using it up. I have a 'descison point' on the ground by which I'll abort if the aeroplane hasn't told me it's happy to climb away by then, and of course I'm watching that as well.
Pilot DAR describes a similar technique any C172 pilot will recognise in getting out of short fields.
Your method of waitng for a certain speed to appear then 'rotating' is crude and does not eek the best performance out of the aeroplane. It's OK for long tarmac runways where you don't need to get the aeroplane out of the mud ASAP, and where runway length isn't limiting.
Otherwise; for max T/O performance fly the wing, not the ASI. The aeroplane will tell you, through the stick, what the wing is doing. If you are sensitive enough to hear it.
Last edited by Shaggy Sheep Driver; 30th Jul 2012 at 20:26.
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Edited to respond to SSD's edit.
So what you meant was 'feel', not 'hear'. Ears hear, hands feel
I still don't think you're particularly disagreeing with me anyway. I never said it wasn't done via feel, just that the Robin picks up at around 55kts, when you hit the bump we were discussing at around 45kts, which is invariably before the plane is ready to fly.
Suggesting I spend the whole take off run staring at the ASI is possibly a touch presumptive. I do everything you have described, but also take the odd, brief glance at the ASI to check where things are at. I find this useful in guaging how close the plane is to telling me when it's ready to fly and one of many factors used in decision making.
Obviously it's also dependant on your level of experience, no doubt if you have 100s of hours you can fly without the aid of any of the instruments if desired, however I think it would be naive to suggest to low hours pilots that they ignore things such as the ASI during take off, as yes they may yet not have built up a suitable level of experience to make judgment calls based solely on the varying feedback through the stick.
So what you meant was 'feel', not 'hear'. Ears hear, hands feel
I still don't think you're particularly disagreeing with me anyway. I never said it wasn't done via feel, just that the Robin picks up at around 55kts, when you hit the bump we were discussing at around 45kts, which is invariably before the plane is ready to fly.
Suggesting I spend the whole take off run staring at the ASI is possibly a touch presumptive. I do everything you have described, but also take the odd, brief glance at the ASI to check where things are at. I find this useful in guaging how close the plane is to telling me when it's ready to fly and one of many factors used in decision making.
Obviously it's also dependant on your level of experience, no doubt if you have 100s of hours you can fly without the aid of any of the instruments if desired, however I think it would be naive to suggest to low hours pilots that they ignore things such as the ASI during take off, as yes they may yet not have built up a suitable level of experience to make judgment calls based solely on the varying feedback through the stick.
Last edited by Ds3; 30th Jul 2012 at 20:41.
The advice I was recently given corresponds largely with DAR's idea.
-) get to know the pitch attitude your plane will sustain in climb
-) start to roll with full stick back
-) as soon as the nosewheel lifts off, release stick to keep the horizon at the optimal pitch, which you have determined before. It may change a bit with gross weight, though.
This way, you lift the delicate nosewheel off the ground as soon as possible, without ever risking a stall. (except perhaps with a gust of tailwind)
Mind you, this advice was given for a microlight, I've no idea if it can be taken to a C172 literally.
NB replace "stick" with "yoke" as appropriate
-) get to know the pitch attitude your plane will sustain in climb
-) start to roll with full stick back
-) as soon as the nosewheel lifts off, release stick to keep the horizon at the optimal pitch, which you have determined before. It may change a bit with gross weight, though.
This way, you lift the delicate nosewheel off the ground as soon as possible, without ever risking a stall. (except perhaps with a gust of tailwind)
Mind you, this advice was given for a microlight, I've no idea if it can be taken to a C172 literally.
NB replace "stick" with "yoke" as appropriate
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Ds3,
As I review my 172RG Flight Manual (I don't have one for a regular 172), to assure that I understand what Cessna expects for speeds before I comment (afterall, they are the experts at this). The normal takeoff says to "Lift the nosewheel at 55KIAS". For the short field takeoff the reference to a speed is replaced by "Maintain slightly tail low attitude". It appears that Cessna (at least for this aircraft) is not requiring any particular speed for a short field takeoff.
Differing years of Cessna flight manuals will have differing phraseology for the same technique, mostly from the evolution of flight manual development and harmonizing the procedures with other types as required.
None the less, you will never go wrong using a short field technique on a longer runway, and it's better for the aircraft. You might have to work a bit more at directional control, but nothing wrong with perfecting your skills that way.
If you are flying a multi crew jet, and the pilot not flying is calling out speeds, then certainly "rotating" at a called speed is appropriate, that's the way those planes were designed to be flown. However, I am critical of a 172 pilot who is "eyes in" on, or close to the ground. . You can feel everything you need to about how the plane is flying, and what it will do next, at those lower speeds. Touch is a sense, as valid as any other, so hone it, and use it along with all the others. One day, out of necessity, you will have to maneuver, with reference to the outside, and you just will not be able to look back at the speed, so you might as well practice.
Of more than 60 light aircraft types I have flown, there is exactly one, which no matter how much attention you pay to the feel of the pitch control, cannot be flown in the extremes by feel alone. The control forces are often null, and sometimes backward. I am not surprised that Canada did not type certify it. That is a Siai Marchetti 1019. Magnificent fun to fly, but you cannot relax...
As said earlier, it is not the "new" pilots I blame for not knowing this stuff, it's the inexperienced instructors. The problem is that many of these instructors don't know that they are inexperienced, so they genuinely think that their way is the right way. They were taught to teach by a curriculum, which did not properly address some aspects of flying. So they don't practice, and the center core of knowledge and technique becomes the full breadth, by a narrowing of the range of experience. Yes, there are many things I will do while flying a plane, which I would never write here. I can do it, and I can mentor it to other pilots, but I can not do it justice in words alone, and I don't want someone screwing up because they tried, 'cause I wrote. Yes, I have many times reselected flaps during takeoffs, but only on 180/185 floatplanes, where the trick really does work, if well co-ordinated. But, just the blanket statement to try it, verges on irresponsible, in the absence of one on one mentoring.
At least in the old "hanger talk" days, there was a chance that when the weather cleared, or the following weekend, the wise skygod would say "c'mon, I'll show you" and you were treated to a real experience. The chat group is a fantastic beginning point in mentoring, but it rapidly falls short when it comes to the follow up of "come with me...".
So some of us here do our best to share our knowledge as best can be done by keyboard, and the odd photo. We can only offer so much though, without being in the plane with you....
As I review my 172RG Flight Manual (I don't have one for a regular 172), to assure that I understand what Cessna expects for speeds before I comment (afterall, they are the experts at this). The normal takeoff says to "Lift the nosewheel at 55KIAS". For the short field takeoff the reference to a speed is replaced by "Maintain slightly tail low attitude". It appears that Cessna (at least for this aircraft) is not requiring any particular speed for a short field takeoff.
Differing years of Cessna flight manuals will have differing phraseology for the same technique, mostly from the evolution of flight manual development and harmonizing the procedures with other types as required.
None the less, you will never go wrong using a short field technique on a longer runway, and it's better for the aircraft. You might have to work a bit more at directional control, but nothing wrong with perfecting your skills that way.
If you are flying a multi crew jet, and the pilot not flying is calling out speeds, then certainly "rotating" at a called speed is appropriate, that's the way those planes were designed to be flown. However, I am critical of a 172 pilot who is "eyes in" on, or close to the ground. . You can feel everything you need to about how the plane is flying, and what it will do next, at those lower speeds. Touch is a sense, as valid as any other, so hone it, and use it along with all the others. One day, out of necessity, you will have to maneuver, with reference to the outside, and you just will not be able to look back at the speed, so you might as well practice.
Of more than 60 light aircraft types I have flown, there is exactly one, which no matter how much attention you pay to the feel of the pitch control, cannot be flown in the extremes by feel alone. The control forces are often null, and sometimes backward. I am not surprised that Canada did not type certify it. That is a Siai Marchetti 1019. Magnificent fun to fly, but you cannot relax...
As said earlier, it is not the "new" pilots I blame for not knowing this stuff, it's the inexperienced instructors. The problem is that many of these instructors don't know that they are inexperienced, so they genuinely think that their way is the right way. They were taught to teach by a curriculum, which did not properly address some aspects of flying. So they don't practice, and the center core of knowledge and technique becomes the full breadth, by a narrowing of the range of experience. Yes, there are many things I will do while flying a plane, which I would never write here. I can do it, and I can mentor it to other pilots, but I can not do it justice in words alone, and I don't want someone screwing up because they tried, 'cause I wrote. Yes, I have many times reselected flaps during takeoffs, but only on 180/185 floatplanes, where the trick really does work, if well co-ordinated. But, just the blanket statement to try it, verges on irresponsible, in the absence of one on one mentoring.
At least in the old "hanger talk" days, there was a chance that when the weather cleared, or the following weekend, the wise skygod would say "c'mon, I'll show you" and you were treated to a real experience. The chat group is a fantastic beginning point in mentoring, but it rapidly falls short when it comes to the follow up of "come with me...".
So some of us here do our best to share our knowledge as best can be done by keyboard, and the odd photo. We can only offer so much though, without being in the plane with you....
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You don't push the nose forward just hold your current attitude
Haven't broken a nosewheel leg yet
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I think it would be naive to suggest to low hours pilots that they ignore things such as the ASI during take off, as yes they may yet not have built up a suitable level of experience to make judgment calls based solely on the varying feedback through the stick.
We see a decline in basic flying skills in airline pilots (Colgan Dash 8, AF 447). When I hear folk talk of 'rotate speeds' in SEPs (which is a term not appropriate to those types) I have similar worries about GA.
Last edited by Shaggy Sheep Driver; 30th Jul 2012 at 21:05.
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Bear in mind Ds3, that the published speeds for any aircraft are selected with a margin, where there is doubt about controllability. One of my project required reducing the best rate of climb speed for a highly modified Caravan by 7 knots. To support that, not only did I have to show the climb performance, but also land back from 50 feet after an engine failure after takeoff, and Fly a complete circuit at 5 knots slower than the book speeds I proposed (so takeoff, circuit approach and land at 75 KIAS). Those two requirements were much more un nerving that the more than dozen spins I had to do in it!
There are margins built in to the numbers. If you get airborne "below" the speed, and are climbing, you will continue to. However, if it quits, your chances of entering a good glide may be very reduced. That's why full flap takeoffs are not approved, not 'cause the plane won't do them!
There are margins built in to the numbers. If you get airborne "below" the speed, and are climbing, you will continue to. However, if it quits, your chances of entering a good glide may be very reduced. That's why full flap takeoffs are not approved, not 'cause the plane won't do them!
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That's why full flap takeoffs are not approved, not 'cause the plane won't do them!
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I am waiting for Pilot Dar to point out the obvious in this discussion......
....airspeed indicators have a lag especially in the low airspeed realm so why in Gods name would you look at the airspeed before you are flying???
Airplanes fly based on angle of attack........chasing an airspeed indicator will only create a roller coaster ride.
By the way Pilot Dar.......I have all my Cub project back home....including the AOA parts..
We really enjoyed your visit to our home and look forward to visiting you in the future.
Chuck E.
....airspeed indicators have a lag especially in the low airspeed realm so why in Gods name would you look at the airspeed before you are flying???
Airplanes fly based on angle of attack........chasing an airspeed indicator will only create a roller coaster ride.
By the way Pilot Dar.......I have all my Cub project back home....including the AOA parts..
We really enjoyed your visit to our home and look forward to visiting you in the future.
Chuck E.
Last edited by Chuck Ellsworth; 31st Jul 2012 at 01:14.
I think the biggest problem low time pilots have with bumpy fields is the fact that the bumps tend to bounce the aircraft into the air before it is quite ready to fly. Whe this happens the tendency is to pull back creating an excessive angle of attack which causes the aircraft to stop accelerating and in extreme cases staggering into the air and then stalling.
As Pilot DAR pointed out establish the attitude that just flies the nose wheel off the ground and hold that. If the airplane bounces into the air hold the attitude if it is ready to fly it will stay in the air, if not it will settle back on the ground and continue accelerating until it is ready to fly.
As for the flaps issue. Well the POH for every model of C 172 says use 10 degs for soft/rough fields. It doesn't say mess with them on the takeoff run.
Your attention is IMHO far better used concentrating holding the takeoff run attitude. Also the POH (the book that nobody in the UK flight training scene ever seems to look at
) for the C172M says the target speed for a short field takeoff is 59 kts at 50 feet AGL. That is the number you should look for after the aircraft has broken ground and started climbing away.
As Pilot DAR pointed out establish the attitude that just flies the nose wheel off the ground and hold that. If the airplane bounces into the air hold the attitude if it is ready to fly it will stay in the air, if not it will settle back on the ground and continue accelerating until it is ready to fly.
As for the flaps issue. Well the POH for every model of C 172 says use 10 degs for soft/rough fields. It doesn't say mess with them on the takeoff run.
Your attention is IMHO far better used concentrating holding the takeoff run attitude. Also the POH (the book that nobody in the UK flight training scene ever seems to look at
) for the C172M says the target speed for a short field takeoff is 59 kts at 50 feet AGL. That is the number you should look for after the aircraft has broken ground and started climbing away.
Last edited by Big Pistons Forever; 31st Jul 2012 at 04:09.
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airspeed indicators have a lag
Strictly speaking, I believe it is the actual change in airspeed that lags behind the pitch change.
Mind you, this hair-splitting does not change the logic of what Chuck Ellsworth said!
-----------------
Edited to remove confusing reference to true airspeed.
Last edited by 24Carrot; 31st Jul 2012 at 09:02.
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That main gear can soak a whole heap punishment the nose wheel can't. I have seen folk drop them from 6ft up onto the deck with spectacular rebounds afterwards no harm apart from pride occured.
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Glad I've got a bit of a debate going!
Big Pistons, yep that's exactly the problem I've found a couple of times on bumpier strips (and what prompted me to ask the question in the first place). You get bumped up into the air at around 40 knots which is below a safe flying speed. So far I've managed to resist the temptation to pull the stick back - I instinctively push the nose forward on the stall warner largely thanks to my instructors drilling it into me during my ppl. The difficulty with it is the risk of overcorrection and bumping the nose wheel back onto the ground.
I guess the "maintain attitude and accelerate in ground effect" technique is actually what I've been doing albeit without realising it. I'm going to do a few experiments with this on my long tarmac base runway to build my confidence for the strips.
I did my PPL on a PA28 from a paved runway and, rightly or wrongly, I was taught to scan the ASI periodically throughout the ground roll and 'rotate'. The PA28 needed positive back pressure to 'unstick' from the runway, whereas the C172 just wants to fly off itself - so this may be the difference, and why the technique is less appropriate for the 172.
Big Pistons, yep that's exactly the problem I've found a couple of times on bumpier strips (and what prompted me to ask the question in the first place). You get bumped up into the air at around 40 knots which is below a safe flying speed. So far I've managed to resist the temptation to pull the stick back - I instinctively push the nose forward on the stall warner largely thanks to my instructors drilling it into me during my ppl. The difficulty with it is the risk of overcorrection and bumping the nose wheel back onto the ground.
I guess the "maintain attitude and accelerate in ground effect" technique is actually what I've been doing albeit without realising it. I'm going to do a few experiments with this on my long tarmac base runway to build my confidence for the strips.
I did my PPL on a PA28 from a paved runway and, rightly or wrongly, I was taught to scan the ASI periodically throughout the ground roll and 'rotate'. The PA28 needed positive back pressure to 'unstick' from the runway, whereas the C172 just wants to fly off itself - so this may be the difference, and why the technique is less appropriate for the 172.