Tightest Radius Turn?
Join Date: Dec 2002
Location: Australia
Posts: 2,382
Likes: 0
Received 0 Likes
on
0 Posts
I did some specific training on my first job for this.
From memory it was full flap, we were very very slow, rate one turns with a fair bit of power on adjusted to silence the horn.
It was a fairly uncomfortable feeling. I think we did it for over an hour, over and over.
If you got caught out you'd have to really be quite quick to react and slow down.
From memory it was full flap, we were very very slow, rate one turns with a fair bit of power on adjusted to silence the horn.
It was a fairly uncomfortable feeling. I think we did it for over an hour, over and over.
If you got caught out you'd have to really be quite quick to react and slow down.
Take FTDK's advice and add full power (if you are saving your life, that is)
If you are flying anything other than a Bonanza, ya might want to give it full power!
Dr
Join Date: Jan 2001
Location: Australia
Posts: 725
Likes: 0
Received 0 Likes
on
0 Posts
And what is the radius of turn, in nm?
Try this javascript Aircraft Turn Radius calculator.
Entry 120kt, AoB 74 degrees 
, 3.6g:
Turn diameter 736 feet, or 0.1nm. Time to turn 180 degrees = 5.7 seconds
Entry 85kt, AoB 60 degrees, 2.0g:
Turn diameter 743 feet, or 0.1nm. Time to turn 180 degrees = 8.1 seconds.
Entry 77kt, AoB 60 degrees, Flap, 2.0g:
Turn diameter 609 feet, or 0.1nm. Time to turn 180 degrees = 7.4 seconds.
You asked for the tightest turning radius, not whether it was a good idea to try it
Entry 60kt, AoB 45 degrees, Flap, 1.4g:
Turn diameter 640 feet, or 0.1nm. Time to turn 180 degrees = 10 seconds.
Performance is secondary to controllability?
Remember Vmca demo during initial twin asymmetrics? "Five to the live" sacrifices a minute amount of vertical component of lift (performance) tilting it toward the live (for control). If you bungle the manouevre and cannot control the heading of the aircraft because you are below Vmca, reduce power to reduce the asymmetric yawing moment and restore control.
Sacrifice performance to maintain control.
Try this javascript Aircraft Turn Radius calculator.
So my question is, which of these approaches, 3.8G at 120 KIAS, 2G at 85 KIAS or 2G at 77KIAS flaps extended to 40 deg. (plus a gust margin and a little bit extra) is going to produce the tightest turning radius?
, 3.6g:Turn diameter 736 feet, or 0.1nm. Time to turn 180 degrees = 5.7 seconds
Entry 85kt, AoB 60 degrees, 2.0g:
Turn diameter 743 feet, or 0.1nm. Time to turn 180 degrees = 8.1 seconds.
Entry 77kt, AoB 60 degrees, Flap, 2.0g:
Turn diameter 609 feet, or 0.1nm. Time to turn 180 degrees = 7.4 seconds.
You asked for the tightest turning radius, not whether it was a good idea to try it
Originally Posted by RandyBandit
Why use 60deg AOB? why fly it fast? You dont want to get out quick, just in minumum radius. Stick to a comfortable, safe Angle of Bank (even rate 1) and fly as slow as the a/c config will let you. The slow speed is what dramatically reduces the radius of the turn.
Turn diameter 640 feet, or 0.1nm. Time to turn 180 degrees = 10 seconds.
Performance is secondary to controllability?
Remember Vmca demo during initial twin asymmetrics? "Five to the live" sacrifices a minute amount of vertical component of lift (performance) tilting it toward the live (for control). If you bungle the manouevre and cannot control the heading of the aircraft because you are below Vmca, reduce power to reduce the asymmetric yawing moment and restore control.
Sacrifice performance to maintain control.
Last edited by ITCZ; 22nd May 2008 at 13:58.
Join Date: Aug 2003
Location: Sale, Australia
Age: 80
Posts: 3,832
Likes: 0
Received 0 Likes
on
0 Posts
Lifted from some notes.
Limit Turns and Manoeuvre Speed
The minimum radius or maximum rate of turn are limited by either the strength of the structure, or by the power available. At low speeds (where the angle of attack is already high), it is not possible to significantly increase the lift coefficient. Therefore the angle of bank is limited by aerodynamic considerations, and under these conditions, it will not be possible to produce the limiting structual load factor. The wing loading and maximum lift coefficient determine the load factor for any speed. See the “Aerodynamic Limit” curve in the graphic.
As the speed is increased from the straight and level stall speed, the radius of turn can be reduced by increasing the angle of bank. However, a radius and speed are reached where the load factor is at a maximum for the structure. Any further increase will overstress the structure. Thus the radius of turn will increase, as the speed is further increased at constant angle of bank. The speed corresponding to the minimum radius turn is called the manoeuvre speed.
At speeds below the manoeuvre speed, the maximum (or limiting) load factor cannot be produced aerodynamically i.e. the angle of bank is limited by the maximum lift coefficient. At speeds above the manoeuvre speed, an increase in the angle of attack to produce maximum lift coefficient, will produce a load factor higher than the limit load factor i.e. it will overstress the structure.
Except in aircraft with a very high thrust to weight ratio, the limit load factor cannot be obtained in a level turn as shown in the graphic. The available thrust (or power) sets a lower limit to the angle of bank. Thus the minimum radius of turn is larger and occurs at a lower speed. When height is increased, the limiting effect becomes more noticeable. Thus at low levels, aerodynamic and structual (if power is sufficient) limits will apply, while at high altitudes, aerodynamic and power limits will apply.
Sunny, with your new found skills how about a stall turn, or perhaps even a Immelman. Zero radius, in the horizontal at least.
Limit Turns and Manoeuvre Speed
The minimum radius or maximum rate of turn are limited by either the strength of the structure, or by the power available. At low speeds (where the angle of attack is already high), it is not possible to significantly increase the lift coefficient. Therefore the angle of bank is limited by aerodynamic considerations, and under these conditions, it will not be possible to produce the limiting structual load factor. The wing loading and maximum lift coefficient determine the load factor for any speed. See the “Aerodynamic Limit” curve in the graphic.
As the speed is increased from the straight and level stall speed, the radius of turn can be reduced by increasing the angle of bank. However, a radius and speed are reached where the load factor is at a maximum for the structure. Any further increase will overstress the structure. Thus the radius of turn will increase, as the speed is further increased at constant angle of bank. The speed corresponding to the minimum radius turn is called the manoeuvre speed.
At speeds below the manoeuvre speed, the maximum (or limiting) load factor cannot be produced aerodynamically i.e. the angle of bank is limited by the maximum lift coefficient. At speeds above the manoeuvre speed, an increase in the angle of attack to produce maximum lift coefficient, will produce a load factor higher than the limit load factor i.e. it will overstress the structure.
Except in aircraft with a very high thrust to weight ratio, the limit load factor cannot be obtained in a level turn as shown in the graphic. The available thrust (or power) sets a lower limit to the angle of bank. Thus the minimum radius of turn is larger and occurs at a lower speed. When height is increased, the limiting effect becomes more noticeable. Thus at low levels, aerodynamic and structual (if power is sufficient) limits will apply, while at high altitudes, aerodynamic and power limits will apply.
Sunny, with your new found skills how about a stall turn, or perhaps even a Immelman. Zero radius, in the horizontal at least.
Join Date: Nov 2003
Location: Up here
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Sunfish can I ask why the turn must be only in the horizontal plane? If you want to turn back with a tight radius you could use the vertical (as Brian said) and do a wingover, which wouldn't over stress a non-aerobatic aircraft.
Join Date: Sep 2006
Location: Melbourne
Posts: 1,569
Likes: 0
Received 0 Likes
on
0 Posts
Some very professional answers coming here but when you really think about it who has remembered in detail & has applied all we have learnt during our flying career studies the finer details of obtaining the min rad turn? Few if any I'd say! I for one admit that from all the ATPL subjects learnt years ago I probably couldn't pass any of the exams again if I sat them today without any study. We learn/pass them at the time & together with that knowledge we go out & really learn it, at the wheel. Tight turns are fraught with danger if you really need to do them then go out & practise at ALT a little at a time, that's where you really learn not in some book!
CW
CW
turn back with a tight radius you could use the vertical
I often chose a canyon route as it gave me lots more options eg normally a road down below so one option was to land straight ahead and wait. Lots of issues with canyon flying, especially with winds and other weather considerations.
(My usual interest in turn radius has nought to do with canyon flying)
Sunfish's original questions were around statements in Dave's book - those statements made in the context of an intro to flight mechanics of a course in basic aerobatics. Sunfish, you might be interested in reading Rich Stowell's book "Emergency Maneuver Training" for more on the subject with different applications in mind - check it out at Skylines.
Join Date: Aug 2003
Location: Sale, Australia
Age: 80
Posts: 3,832
Likes: 0
Received 0 Likes
on
0 Posts
ITCZ - you may be right, have collected a library of odd bits of material from all over the place.
Wally - how right you are about stuff learnt to pass exams and promptly forget. As for passing exams doubt whether I could manage a PPL. Min radius turns are at the fore front of most military pilots skill set though, particularly fighter types.
Wally - how right you are about stuff learnt to pass exams and promptly forget. As for passing exams doubt whether I could manage a PPL. Min radius turns are at the fore front of most military pilots skill set though, particularly fighter types.
