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#1
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Hey guys,
I'm sure this has been discussed in this forum before, but a rather detailed google search back didn't come up with anything concrete, and I have been wondering about it. All of the recent discussion of take-offs has had me wondering - how do you do it? There are 3 "official" procedures outlined in the FAA Private pilot's manual- Standard Takeoff- Flaps per POH (usually retracted), accelerate smoothly to Vr, put the aircraft into Vy attitude, let the plane climb away on its own. Short Field Takeoff- Flaps per POH (usually 1 notch or so), accelerate quickly to Vr, put the aircraft into Vx attitude, let the aircraft climb away on its own, drop the nose and take Vy attitude as soon as passed obstacle altitude. Soft Field Takeoff- Flaps per POH (usually 1 notch or so), accelerate to Vr, pull back firmly to get the aircraft into ground effect, then lower the nose again once in ground effect and let the aircraft accellerate to Vx or Vy, depending upon whether or not there are obstacles to clear. Simple enough. However, my instructor, and several of you guys use a technique not listed above- "popular" takeoff- Flaps per POH (usually retracted), accelerate to Vr, pull mains off, lower nose in ground effect, and accelerate to Vx or Vy as necessary in ground effect (even on a hard surface runway) before climbing away. Its basically a flaps-less soft-field takeoff even on firm runways. My instructor gives several reasons for this takeoff- 1- Air is better than the best oleo strut, smoother takeoff for passengers. 2- The plane accelerates faster in ground effect (without the wheel drag) 3- It allows you to crab into a crosswind sooner, getting you out of a draggy slip condition. 4- Less wear on both the struts and the tires. 5- Its absolutely essential at high DA altitude airports 6- It gets you in 'practice' for short-field takeoffs (the only difference between your normal takeoff and the short field takeoff is flap setting)... I.E, they're nothing special and nothing to worry about. The FAA manual lists the primary danger of "premature liftoff" as power-on stall and the risk of the aircraft settling back onto the runway... This makes sense, but honestly even in my underpowered little cherokee, once I get the mains off and I'm set up in ground effect, sink doesn't seem to be an issue- she seems perfectly happy to "hover" down the runway building speed. I would imagine there might be a risk if a ham-fisted pilot doesn't ease the elevator-pressure back enough and climbs out of ground effect too early- but that takes no more finesse then a coordinated turn - its just a simple pilot skill that quickly becomes second nature. So if the 'hybrid' takeoff above really does have all of these advantages, why isn't it 'recommended' per the FAA handbook? How do you guys do it? Just looking for some guidance from the more experienced pilots on here ![]() -Scott |
#2
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After getting my students finished up with all the PTS landings I
always go out and do "family landings" with them. -Robert |
#3
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So if the 'hybrid' takeoff above really does have all of these
advantages, why isn't it 'recommended' per the FAA handbook? How do you guys do it? I've found that on a hard surface runway (in a Cherokee), between the time I start rotation to the time the wheels lift off, I've already got flying speed. I've done the "lower the nose to accelerate in ground effect" thing but I don't get more than a few seconds of that before I'm already past climb speed. On a short field, every second matters, but I expected more of a difference. The Cutlass (C-172 RG) POH says, for high altitude, to lean to best RPM, and (if I remember right) use a notch or two of flap. But the odd thing is that the POH says to hold the wheel back during the takeoff roll, rather than let the airplane accelerate on the ground first. The airplane will start to take off and gently bounce on the runway a few times as it builds speed. Seems to me this is wasting energy somewhere. Jose -- "Never trust anything that can think for itself, if you can't see where it keeps its brain." (chapter 10 of book 3 - Harry Potter). for Email, make the obvious change in the address. |
#4
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EridanMan wrote
Standard Takeoff- Flaps per POH (usually retracted), accelerate smoothly to Vr, put the aircraft into Vy attitude, let the plane climb away on its own. YES Short Field Takeoff- Flaps per POH (usually 1 notch or so), accelerate quickly to Vr, put the aircraft into Vx attitude, let the aircraft climb away on its own, drop the nose and take Vy attitude as soon as passed obstacle altitude. YES Soft Field Takeoff- Flaps per POH (usually 1 notch or so), accelerate to Vr, pull back firmly to get the aircraft into ground effect, then lower the nose again once in ground effect and let the aircraft accellerate to Vx or Vy, depending upon whether or not there are obstacles to clear. NO....The following is from the FAA's Airplane Flying Handbook 5-10 TAKEOFF ROLL As the airplane is aligned with the takeoff path, takeoff power is applied smoothly and as rapidly as the powerplant will accept it without faltering. As the airplaneaccelerates, enough back-elevator pressure should be applied to establish a positive angle of attack and to reduce the weight supported by the nosewheel. When the airplane is held at a nose-high attitude throughout the takeoff run, the wings will, as speed increases and lift develops, progressively relieve the wheels of more and more of the airplane’s weight, thereby minimizing the drag caused by surface irregularities or adhesion. If this attitude is accurately maintained, the airplane will virtually fly itself off the ground, becoming airborne at airspeed slower than a safe climb speed because of ground effect. [Figure 5-9] LIFT-OFF After becoming airborne, the nose should be lowered very gently with the wheels clear of the surface to allow the airplane to accelerate to VY, or VX if obstacles must be cleared. Extreme care must be exercised immediately after the airplane becomes airborne and while it accelerates, to avoid settling back onto the surface. An attempt to climb prematurely or too steeply may cause the airplane to settle back to the surface as a result of losing the benefit of ground effect. An attempt to climb out of ground effect before sufficient climb airspeed is attained may result in the airplane being unable to climb further as the ground effect area is transited, even with full power. Therefore, it is essential that the airplane remain in ground effect until at least VX is reached. This requires feel for the airplane, and a very fine control touch, in order to avoid over-controlling the elevator as required control pressures change with airplane acceleration. "popular" takeoff- Flaps per POH (usually retracted), accelerate to Vr, pull mains off, lower nose in ground effect, and accelerate to Vx or Vy as necessary in ground effect (even on a hard surface runway) before climbing away. NO Bob Moore ATP CFI(I) PanAm (retired) |
#5
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I'm still trying to figure out how to accelerate "smoothly," "rapidly," or
just plain accelerate when my every-time practice is to push the throttle full forward. Bob Gardner "EridanMan" wrote in message oups.com... Hey guys, I'm sure this has been discussed in this forum before, but a rather detailed google search back didn't come up with anything concrete, and I have been wondering about it. All of the recent discussion of take-offs has had me wondering - how do you do it? There are 3 "official" procedures outlined in the FAA Private pilot's manual- Standard Takeoff- Flaps per POH (usually retracted), accelerate smoothly to Vr, put the aircraft into Vy attitude, let the plane climb away on its own. Short Field Takeoff- Flaps per POH (usually 1 notch or so), accelerate quickly to Vr, put the aircraft into Vx attitude, let the aircraft climb away on its own, drop the nose and take Vy attitude as soon as passed obstacle altitude. Soft Field Takeoff- Flaps per POH (usually 1 notch or so), accelerate to Vr, pull back firmly to get the aircraft into ground effect, then lower the nose again once in ground effect and let the aircraft accellerate to Vx or Vy, depending upon whether or not there are obstacles to clear. Simple enough. However, my instructor, and several of you guys use a technique not listed above- "popular" takeoff- Flaps per POH (usually retracted), accelerate to Vr, pull mains off, lower nose in ground effect, and accelerate to Vx or Vy as necessary in ground effect (even on a hard surface runway) before climbing away. Its basically a flaps-less soft-field takeoff even on firm runways. My instructor gives several reasons for this takeoff- 1- Air is better than the best oleo strut, smoother takeoff for passengers. 2- The plane accelerates faster in ground effect (without the wheel drag) 3- It allows you to crab into a crosswind sooner, getting you out of a draggy slip condition. 4- Less wear on both the struts and the tires. 5- Its absolutely essential at high DA altitude airports 6- It gets you in 'practice' for short-field takeoffs (the only difference between your normal takeoff and the short field takeoff is flap setting)... I.E, they're nothing special and nothing to worry about. The FAA manual lists the primary danger of "premature liftoff" as power-on stall and the risk of the aircraft settling back onto the runway... This makes sense, but honestly even in my underpowered little cherokee, once I get the mains off and I'm set up in ground effect, sink doesn't seem to be an issue- she seems perfectly happy to "hover" down the runway building speed. I would imagine there might be a risk if a ham-fisted pilot doesn't ease the elevator-pressure back enough and climbs out of ground effect too early- but that takes no more finesse then a coordinated turn - its just a simple pilot skill that quickly becomes second nature. So if the 'hybrid' takeoff above really does have all of these advantages, why isn't it 'recommended' per the FAA handbook? How do you guys do it? Just looking for some guidance from the more experienced pilots on here ![]() -Scott |
#6
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![]() 1- Air is better than the best oleo strut, smoother takeoff for passengers. True, But not a very smooth takeoff as you have pitch up, pitch down and then pitch back up. 2- The plane accelerates faster in ground effect (without the wheel drag) False in most cases on a paved runway, In fact I watched a Commache Crash doing this. Fully loaded he was off the ground in 1500 feet in ground affect nose high. He flew off the end of the 5000 foot runway still nose high and only 4 feet off the ground before he aborted the take off. He never was able to reach his best climb speed in the nose high, high drag configuration. 3- It allows you to crab into a crosswind sooner, getting you out of a draggy slip condition. True, But good crosswind rudder and aileron control input will usually let you take off without having to do so. (Raise the downwind wing and keep straight with the rudder) 4- Less wear on both the struts and the tires. True 5- Its absolutely essential at high DA altitude airports Absolutely False, See response to #2 DA was a significant factor in that accident, But if proper short field technique had been used I believe they would not have had an issue. 6- It gets you in 'practice' for short-field takeoffs (the only difference between your normal takeoff and the short field takeoff is flap setting)... I.E, they're nothing special and nothing to worry about. Did you mean Soft Field? It will get you in practice for Soft Feilds. For Short Feilds you should accelerate on the main gear controls about neutral (low drag) until within about 5 knots of you Vx speed. Rotate and maintain Vx. (Note a few airplanes will lift off in a level attitude prior to Vx, if so, then float in ground affect until with a few knots of Vx) Brian CFIIG/ASEL |
#7
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Bob -
Yes, I misquoted the soft-field procedure, i'm sorry (I don't have the book in front of me). Could you elaborate more on your 'no' for the procedure I mentioned? I'm more interested in why one particular talkoff procedure over another... This is about increasing my personal understanding more than it is about simply being told 'what the book says' so to speak. Brian- Thanks for your input, some quick responses- True, But not a very smooth takeoff as you have pitch up, pitch down and then pitch back up. Done 'correctly' (again, I'm not 100% sure I'm correct, but the old timers at my club swear by it), the pitch down after attaining ground effect is very subtle... I do have to say that it "feels" really smooth. False in most cases on a paved runway, In fact I watched a Commache Crash doing this. Fully loaded he was off the ground in 1500 feet in ground affect nose high. He flew off the end of the 5000 foot runway still nose high and only 4 feet off the ground before he aborted the take off. He never was able to reach his best climb speed in the nose high, high drag configuration. Hmm... that's interesting, my initial sophomoric instinct suggests that perhaps he didn't release enough of the back-pressure to accelerate enough... but as I said - purely sophomoric judgement there. True, But good crosswind rudder and aileron control input will usually let you take off without having to do so. (Raise the downwind wing and keep straight with the rudder) A slip is still a slip though, isn't it? even if you're correctly downwind-wing-high and on your upwind gear, the wind is still striking the fuselage at an angle. False, See response to #2 DA was a significant factor in that accident, But if proper short field technique had been used I believe they would not have had an issue. I have no experience with higher DA yet, so I am completely un-qualified to comment I suppose - I am merely quoting what i have been told ![]() Did you mean Soft Field? yes |
#8
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![]() Could you elaborate more on your 'no' for the procedure I mentioned? I'm more interested in why one particular talkoff procedure over another... This is about increasing my personal understanding more than it is about simply being told 'what the book says' so to speak. Sure, True, But not a very smooth takeoff as you have pitch up, pitch down and then pitch back up. Done 'correctly' (again, I'm not 100% sure I'm correct, but the old timers at my club swear by it), the pitch down after attaining ground effect is very subtle... I do have to say that it "feels" really smooth. It can be done very smoothly but this is normally done by not lifting off at minimum airspeed (full up elevator) but rather just raising the nose to about the normal climb attitude. Doing this the aircraft will lift off at a lower than normal climb speed float in the ground affect until reaching the normal climb speed and then climb out. You will have to adjust the elevator as the aircraft accelerates but the attitude will not change. I often teach this to new students because it is simple and works really well and you don't have to look at the ASI at all to do so. Just let the airplane accelerate until you just before you think it is ready to fly, Pull back to raise the nose of the aircraft until the top of the spinner is just below the Horizon (will vary some with different aircraft and pilots) and hold it there. You can try this by starting out with full elevator and as soon a the attitude reaches your nomal climb attitude hold it there. This is often done on gravel runways to raise the propeller as high off the ground as possible. This disadvantage to this technique is that the high angle of attack while still on the ground extends the ground run due to the extra drag caused by the high angle of attack. False in most cases on a paved runway, In fact I watched a Commache Crash doing this. Fully loaded he was off the ground in 1500 feet in ground affect nose high. He flew off the end of the 5000 foot runway still nose high and only 4 feet off the ground before he aborted the take off. He never was able to reach his best climb speed in the nose high, high drag configuration. Hmm... that's interesting, my initial sophomoric instinct suggests that perhaps he didn't release enough of the back-pressure to accelerate enough... but as I said - purely sophomoric judgement there. The biggest issue he had was he was using a modified soft feild technique when he should have been using a short field technique due to the high DA and Gross weight. I suspect he always took off this way and in a 250HP high performance aircraft it didn't occur to him that he should have been using a short feild. It did not occur to him to lower the nose because doing so in this situation would have caused him to settle back onto the runway. True, But good crosswind rudder and aileron control input will usually let you take off without having to do so. (Raise the downwind wing and keep straight with the rudder) A slip is still a slip though, isn't it? even if you're correctly downwind-wing-high and on your upwind gear, the wind is still striking the fuselage at an angle. Yes it is a slip, but having a little extra speed after lift off will prevent you from settling back on the runway and it is better to be aligned with the runway if you do settle back onto the runway. Once a positive rate of climb is established then release the rudder pressure to a normal climb setting and let the aircraft Crab into the wind for maximum climb rate or angle. ----- Perhaps I didn't respond correctly to your 1st post. It just got my attention because I have seen an accident caused by this technique. But the accident was probably caused more by the fact that this was not the technique to use in that situation. You were asking more about Normal Take off's and landing. The technique your instructor recommends will work just fine for normal takes-offs. Here are my points on it remembering these are normal takes offs. 1 Plus, Helps protect the Prop from Debris. 2. Minus, Longer take off roll due to high angle of attack while stilling rolling 3. Minus, Slight less control lifting off at minimum flying speed, some chance of settling back onto runway. 4, Slight Plus, Less wear and tear on tires and struts (minimual difference in my opinion) Hope this helps Brian CFIIG/ASEL |
#9
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![]() Could you elaborate more on your 'no' for the procedure I mentioned? I'm more interested in why one particular talkoff procedure over another... This is about increasing my personal understanding more than it is about simply being told 'what the book says' so to speak. Sure, True, But not a very smooth takeoff as you have pitch up, pitch down and then pitch back up. Done 'correctly' (again, I'm not 100% sure I'm correct, but the old timers at my club swear by it), the pitch down after attaining ground effect is very subtle... I do have to say that it "feels" really smooth. It can be done very smoothly but this is normally done by not lifting off at minimum airspeed (full up elevator) but rather just raising the nose to about the normal climb attitude. Doing this the aircraft will lift off at a lower than normal climb speed float in the ground affect until reaching the normal climb speed and then climb out. You will have to adjust the elevator as the aircraft accelerates but the attitude will not change. I often teach this to new students because it is simple and works really well and you don't have to look at the ASI at all to do so. Just let the airplane accelerate until you just before you think it is ready to fly, Pull back to raise the nose of the aircraft until the top of the spinner is just below the Horizon (will vary some with different aircraft and pilots) and hold it there. You can try this by starting out with full elevator and as soon a the attitude reaches your nomal climb attitude hold it there. This is often done on gravel runways to raise the propeller as high off the ground as possible. This disadvantage to this technique is that the high angle of attack while still on the ground extends the ground run due to the extra drag caused by the high angle of attack. False in most cases on a paved runway, In fact I watched a Commache Crash doing this. Fully loaded he was off the ground in 1500 feet in ground affect nose high. He flew off the end of the 5000 foot runway still nose high and only 4 feet off the ground before he aborted the take off. He never was able to reach his best climb speed in the nose high, high drag configuration. Hmm... that's interesting, my initial sophomoric instinct suggests that perhaps he didn't release enough of the back-pressure to accelerate enough... but as I said - purely sophomoric judgement there. The biggest issue he had was he was using a modified soft feild technique when he should have been using a short field technique due to the high DA and Gross weight. I suspect he always took off this way and in a 250HP high performance aircraft it didn't occur to him that he should have been using a short feild. It did not occur to him to lower the nose because doing so in this situation would have caused him to settle back onto the runway. True, But good crosswind rudder and aileron control input will usually let you take off without having to do so. (Raise the downwind wing and keep straight with the rudder) A slip is still a slip though, isn't it? even if you're correctly downwind-wing-high and on your upwind gear, the wind is still striking the fuselage at an angle. Yes it is a slip, but having a little extra speed after lift off will prevent you from settling back on the runway and it is better to be aligned with the runway if you do settle back onto the runway. Once a positive rate of climb is established then release the rudder pressure to a normal climb setting and let the aircraft Crab into the wind for maximum climb rate or angle. ----- Perhaps I didn't respond correctly to your 1st post. It just got my attention because I have seen an accident caused by this technique. But the accident was probably caused more by the fact that this was not the technique to use in that situation. You were asking more about Normal Take off's and landing. The technique your instructor recommends will work just fine for normal takes-offs. Here are my points on it remembering these are normal takes offs. 1 Plus, Helps protect the Prop from Debris. 2. Minus, Longer take off roll due to high angle of attack while stilling rolling 3. Minus, Slight less control lifting off at minimum flying speed, some chance of settling back onto runway. 4, Slight Plus, Less wear and tear on tires and struts (minimual difference in my opinion) Hope this helps Brian CFIIG/ASEL |
#10
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![]() Could you elaborate more on your 'no' for the procedure I mentioned? I'm more interested in why one particular talkoff procedure over another... This is about increasing my personal understanding more than it is about simply being told 'what the book says' so to speak. Sure, True, But not a very smooth takeoff as you have pitch up, pitch down and then pitch back up. Done 'correctly' (again, I'm not 100% sure I'm correct, but the old timers at my club swear by it), the pitch down after attaining ground effect is very subtle... I do have to say that it "feels" really smooth. It can be done very smoothly but this is normally done by not lifting off at minimum airspeed (full up elevator) but rather just raising the nose to about the normal climb attitude. Doing this the aircraft will lift off at a lower than normal climb speed float in the ground affect until reaching the normal climb speed and then climb out. You will have to adjust the elevator as the aircraft accelerates but the attitude will not change. I often teach this to new students because it is simple and works really well and you don't have to look at the ASI at all to do so. Just let the airplane accelerate until you just before you think it is ready to fly, Pull back to raise the nose of the aircraft until the top of the spinner is just below the Horizon (will vary some with different aircraft and pilots) and hold it there. You can try this by starting out with full elevator and as soon a the attitude reaches your nomal climb attitude hold it there. This is often done on gravel runways to raise the propeller as high off the ground as possible. This disadvantage to this technique is that the high angle of attack while still on the ground extends the ground run due to the extra drag caused by the high angle of attack. False in most cases on a paved runway, In fact I watched a Commache Crash doing this. Fully loaded he was off the ground in 1500 feet in ground affect nose high. He flew off the end of the 5000 foot runway still nose high and only 4 feet off the ground before he aborted the take off. He never was able to reach his best climb speed in the nose high, high drag configuration. Hmm... that's interesting, my initial sophomoric instinct suggests that perhaps he didn't release enough of the back-pressure to accelerate enough... but as I said - purely sophomoric judgement there. The biggest issue he had was he was using a modified soft feild technique when he should have been using a short field technique due to the high DA and Gross weight. I suspect he always took off this way and in a 250HP high performance aircraft it didn't occur to him that he should have been using a short feild. It did not occur to him to lower the nose because doing so in this situation would have caused him to settle back onto the runway. True, But good crosswind rudder and aileron control input will usually let you take off without having to do so. (Raise the downwind wing and keep straight with the rudder) A slip is still a slip though, isn't it? even if you're correctly downwind-wing-high and on your upwind gear, the wind is still striking the fuselage at an angle. Yes it is a slip, but having a little extra speed after lift off will prevent you from settling back on the runway and it is better to be aligned with the runway if you do settle back onto the runway. Once a positive rate of climb is established then release the rudder pressure to a normal climb setting and let the aircraft Crab into the wind for maximum climb rate or angle. ----- Perhaps I didn't respond correctly to your 1st post. It just got my attention because I have seen an accident caused by this technique. But the accident was probably caused more by the fact that this was not the technique to use in that situation. You were asking more about Normal Take off's and landing. The technique your instructor recommends will work just fine for normal takes-offs. Here are my points on it remembering these are normal takes offs. 1 Plus, Helps protect the Prop from Debris. 2. Minus, Longer take off roll due to high angle of attack while stilling rolling 3. Minus, Slight less control lifting off at minimum flying speed, some chance of settling back onto runway. 4, Slight Plus, Less wear and tear on tires and struts (minimual difference in my opinion) Hope this helps Brian CFIIG/ASEL |
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