Power-Off 180's Help
#21
Line Holder
Joined APC: Nov 2012
Position: Left Seat
Posts: 55
I also ensure that when someone walks in to do an aircraft checkout that they understand the concept of them as well. Not everyone who fly's GA (actually very few) has their Commercial. This is a fundamental skill that can help save your life one day.
#22
Power off 180's have always been a fav of mine and one I was taught while doing my initial and did all the way up through my CFI... Of course each glide profile is different per aircraft. It was always a favorite maneuver of mine to do in the Piper Arrow. Always begin that turn right away because it doesnt glide like a C-172 does. So it will sink like a brick literally..
So, now Im truly analysing things on this maneuver and just tieing myself up in a knot..When I did this for my commercial SEL and then my CFI initial, I always pulled the engine abeam the numbers and then the touch down will eventually happen around the 1000 ft marker. Even the DPE told me to touch down in the 1000 ft marker area and I did so spot on.. And according the PTS, its 200 ft beyond this point you are permitted.
I think I am confusing aiming point and the touch down point.. Because in real life, aiming point is the numbers and touch down at 1000 ft marker..
the PTS said you should pull the engine abeam the point that you are aiming for. then surely one should have the aiming point when he is abeam the 1000 ft marker ? Or Aiming point is still abeam the numbers and touch down after floating, at the 1000 ft markers.. For me, I always hit it around the 1000 ft marker...
So, now Im truly analysing things on this maneuver and just tieing myself up in a knot..When I did this for my commercial SEL and then my CFI initial, I always pulled the engine abeam the numbers and then the touch down will eventually happen around the 1000 ft marker. Even the DPE told me to touch down in the 1000 ft marker area and I did so spot on.. And according the PTS, its 200 ft beyond this point you are permitted.
I think I am confusing aiming point and the touch down point.. Because in real life, aiming point is the numbers and touch down at 1000 ft marker..
the PTS said you should pull the engine abeam the point that you are aiming for. then surely one should have the aiming point when he is abeam the 1000 ft marker ? Or Aiming point is still abeam the numbers and touch down after floating, at the 1000 ft markers.. For me, I always hit it around the 1000 ft marker...
#25
Yes, wind conditions will influence how each power off 180 will look. Some will have to make the turn more quickly than others.. Remember you have to make a 180 degree turn and you have 1000 feet to dissipate and if you're at standard rate of turn, that be 60 seconds to complete a 180 degree turn.. So when you pitch for Vg, refer to your VSI and gauge what altitude you be at when you complete the first 90 degree turn... Once that runway is made, then it becomes a normal landing. You can easily bleed out airspeed or altitude accordingly but when you are low or slow, then you cannot convert that to stretch your glide and you fall short .. Some get it right the first time they do it. Most times on this , you do float a fair amount and then touch down in a normal landing attitude without forcing the airplane on the runway..
#27
Thanks everyone for the help, doing much better with the power off 180's. Now after schedule conflicts, weather, and a broken airplane my only problem now is apeasing the flying gods so that I don't have keep rescheduling my checkride . So if anyone knows of sacraficial virgin that's not doing anything, let me know!
#28
Solution. Fly a normal pattern except turn base at the 30 degree point and not the normal 45. When on base, if you're high turn a tight final and use a slip if needed, if you're low turn direct to the numbers. This seems to work 9 out of 10 times. Let me know how it goes
#29
Gets Weekends Off
Joined APC: Mar 2009
Position: Lunar Lander Commander
Posts: 158
Read the book "Stick and Rudder".
There is this thing called Angular Distance. When an airplane glides it comes down on a particular angle. This "Visual" angle can be measured in degrees below the horizon line. Pull the power, trim for best glide at 3000 feet and find the point on the ground ahead where the airplane is going to hit. This point will not move on the angle, it will simply come toward you as you are going toward it. All other points out of glide range (above it and closer to the horizon) will move up in your window (closer to the horizon) as you glide. All points well inside your glide range (below it and further from the horizon) will appear to move down in the window or move further from the horizon. You will notice these later points eventually disappear under the nose as you begin to fly over them.
Note that the only angle that stays constant relative to the horizon is the angle from your eyes to the point on the ground the airplane is going too in its glide. If this were your emergency landing field you would barely make it as long as the headwind component did not increase and you hold on to your best glide airspeed very precisely.
Now go around and climb back up to the same point you pulled your power off before, same heading and altitude. Pull your power back to idle again, put the gear and flaps all the way down and trim for your final approach speed. Now notice off course that the new point on the ground that stays stationary is much closer to the aircraft. You have a much steeper angular distance than before.
Now lets compare these 2 angles. We have the somewhat shallow best glide/clean angle and the much steeper dirtied up angle. Remember these are angles between your eye point and the spot on the ground the airplane is gliding to (not moving relative to the horizon) and the horizon itself and back to the eye point. This creates an imaginary Scalene triangle in the vertical. One for the clean and one for the dirty. Now do another one for gear down and flaps up. This will give you something between the clean and dirty, remember this because this is what we will use for our power off 180.
Now for the power off 180.
Put your gear down on downwind first that way you do not forget it during all the excitement. Pick aim point on the runway. I use the 2nd stripe up from the #'s or the displace threshold if there is one. Your touchdown point will be a predictable distance beyond this, usually 200-300 feet depending on airspeed and headwind component, you will need this for your PTS tolerances of 200' beyond/0 before TOUCHDOWN point. Your downwind spacing should be no greater than half way up the wing. Note this makes for a very steep angular distance, much greater than your dirtied up one. When abeam the AP pull power to idle slow to approach speed, do not use any flaps yet and note as you are now flying away from your AP the angular distance is decreasing (point moving towards horizon or up in your left rear window). You should also be in a shallow bank as well since this is a power off 180. Now since you are not allowed to add power but nothing says you cannot add drag go ahead and use your flaps and slight turn radius variance to make sure the aircraft is always a little above the dirtied up angle. As you progress through the maneuver it will be easier to judge and you should be bringing in flaps because you are noting you are to high. Once on final or inbound you will adjust your flaps until you see your aim point stop moving down and come towards you instead. If now the aim point starts moving up you overdid the flaps or your turn radius was to wide (downwind spacing) and you failed the maneuver. Go around and try again.
The basic premise here is that you start this maneuver a little too high while clean (except gear) and you are at the 90 point (base) a little too high while cleanish (except gear) and when you are finally more or less facing your aim point it is MUCH easier to judge it's relative movement on the angle and immediately you sink in more flaps (if flaps are all the way down use a forward slip) so the ship comes right down to it.
Good luck!
There is this thing called Angular Distance. When an airplane glides it comes down on a particular angle. This "Visual" angle can be measured in degrees below the horizon line. Pull the power, trim for best glide at 3000 feet and find the point on the ground ahead where the airplane is going to hit. This point will not move on the angle, it will simply come toward you as you are going toward it. All other points out of glide range (above it and closer to the horizon) will move up in your window (closer to the horizon) as you glide. All points well inside your glide range (below it and further from the horizon) will appear to move down in the window or move further from the horizon. You will notice these later points eventually disappear under the nose as you begin to fly over them.
Note that the only angle that stays constant relative to the horizon is the angle from your eyes to the point on the ground the airplane is going too in its glide. If this were your emergency landing field you would barely make it as long as the headwind component did not increase and you hold on to your best glide airspeed very precisely.
Now go around and climb back up to the same point you pulled your power off before, same heading and altitude. Pull your power back to idle again, put the gear and flaps all the way down and trim for your final approach speed. Now notice off course that the new point on the ground that stays stationary is much closer to the aircraft. You have a much steeper angular distance than before.
Now lets compare these 2 angles. We have the somewhat shallow best glide/clean angle and the much steeper dirtied up angle. Remember these are angles between your eye point and the spot on the ground the airplane is gliding to (not moving relative to the horizon) and the horizon itself and back to the eye point. This creates an imaginary Scalene triangle in the vertical. One for the clean and one for the dirty. Now do another one for gear down and flaps up. This will give you something between the clean and dirty, remember this because this is what we will use for our power off 180.
Now for the power off 180.
Put your gear down on downwind first that way you do not forget it during all the excitement. Pick aim point on the runway. I use the 2nd stripe up from the #'s or the displace threshold if there is one. Your touchdown point will be a predictable distance beyond this, usually 200-300 feet depending on airspeed and headwind component, you will need this for your PTS tolerances of 200' beyond/0 before TOUCHDOWN point. Your downwind spacing should be no greater than half way up the wing. Note this makes for a very steep angular distance, much greater than your dirtied up one. When abeam the AP pull power to idle slow to approach speed, do not use any flaps yet and note as you are now flying away from your AP the angular distance is decreasing (point moving towards horizon or up in your left rear window). You should also be in a shallow bank as well since this is a power off 180. Now since you are not allowed to add power but nothing says you cannot add drag go ahead and use your flaps and slight turn radius variance to make sure the aircraft is always a little above the dirtied up angle. As you progress through the maneuver it will be easier to judge and you should be bringing in flaps because you are noting you are to high. Once on final or inbound you will adjust your flaps until you see your aim point stop moving down and come towards you instead. If now the aim point starts moving up you overdid the flaps or your turn radius was to wide (downwind spacing) and you failed the maneuver. Go around and try again.
The basic premise here is that you start this maneuver a little too high while clean (except gear) and you are at the 90 point (base) a little too high while cleanish (except gear) and when you are finally more or less facing your aim point it is MUCH easier to judge it's relative movement on the angle and immediately you sink in more flaps (if flaps are all the way down use a forward slip) so the ship comes right down to it.
Good luck!
#30
Line Holder
Joined APC: Nov 2012
Position: FO FOREVER....
Posts: 73
first Vg dont lower the gear until base and use flaps 10 ( first notch ) be close from the rwy environment .. and make shallow turns ... when base gear down ... and depends if you are high or low put flaps as required ... remember to mantain Vg all the time .. .and dont rush to land with full flaps.. remember more flaps more drag ( more descent rate and less gliding distance )
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