A320/321 Max Rate of Climb Speeds
Thread Starter
Join Date: Feb 2007
Location: Eire
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
A320/321 Max Rate of Climb Speeds
Hello!
Can anyone tell me how to calculate the best rate of climb speeds for the 320/321?? I am aware that entering a cost idex of "0" will give you a managed target climb speed which will privde maximum rate, but is there any rule of thumb (such as VLS + X, or Green Dot + Y) to work it out in advance??
Cheers!!
APE
Can anyone tell me how to calculate the best rate of climb speeds for the 320/321?? I am aware that entering a cost idex of "0" will give you a managed target climb speed which will privde maximum rate, but is there any rule of thumb (such as VLS + X, or Green Dot + Y) to work it out in advance??
Cheers!!
APE
Thread Starter
Join Date: Feb 2007
Location: Eire
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
I think what you are referring to is the best angle of climb speed. Green Dot is the minimum drag speed and will therefore give you the best angle. What I am after is the best rate. For an average 320/321 at mid altitudes and average weights it should be in the region of 275 Knots or so.
If you were only at Green Dot at FL 300, you would be using quite a bit less than maximum thrust. In the event of an RA you would have to apply TOGA and maintain VLS as a minimum. But, yes, you would be unlikely to achieve 1500 FPM for any decent length of time.
If you were only at Green Dot at FL 300, you would be using quite a bit less than maximum thrust. In the event of an RA you would have to apply TOGA and maintain VLS as a minimum. But, yes, you would be unlikely to achieve 1500 FPM for any decent length of time.
Join Date: Jan 2001
Location: Dirty Sands
Age: 62
Posts: 125
Likes: 0
Received 0 Likes
on
0 Posts
Green Dot would give you the best Lift/Drag ratio, hence the best angle of climb (or holding speed).
For want of anything better and for practical purposes I use Econ Climb Speed at Cost Index 0. This was Boeing logic (I know, Boeing) but laws of physics are universal and the FMC/FMGC are the same make.
I have read somewhere in one of the Airbus FCTM versions that you can use Turbulence penetration speed to get the best rate.
And another consideration would be whether you refer to a static (constant speed) vs a dynamic maneouver (such as on an RA) where you'd get the best rate by trading speed energy for climb rate.
My two cents.
For want of anything better and for practical purposes I use Econ Climb Speed at Cost Index 0. This was Boeing logic (I know, Boeing) but laws of physics are universal and the FMC/FMGC are the same make.
I have read somewhere in one of the Airbus FCTM versions that you can use Turbulence penetration speed to get the best rate.
And another consideration would be whether you refer to a static (constant speed) vs a dynamic maneouver (such as on an RA) where you'd get the best rate by trading speed energy for climb rate.
My two cents.
Thread Starter
Join Date: Feb 2007
Location: Eire
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
Thanks TE RANGI!
I agree that the speed/altitude trade is obviously the best for short term situations. It's the long term one that I'm interested in.
Very interesting about the FCTM mentioning the use of turbulence speeds for best rate. I'll start diggin throught the version I have to see if I can find anything.
Thanks!
I agree that the speed/altitude trade is obviously the best for short term situations. It's the long term one that I'm interested in.
Very interesting about the FCTM mentioning the use of turbulence speeds for best rate. I'll start diggin throught the version I have to see if I can find anything.
Thanks!
Join Date: Mar 2000
Location: Sunrise Senior Living
Posts: 1,338
Likes: 0
Received 0 Likes
on
0 Posts
From Airbus ''Getting to grips with Aircraft Performance'' 2.2.4:
'To minimize overall fuel consumption during flight, a low CI must be used. As the climb phase is fuel consuming, it is advantageous to minmize climb duration. This is achieved at the maximum rate climb speed. CI 0 gives IASecon which is Max Rate Climb Speed.'
It seems to work out most times about 270KIAS in the A319.
For the above publication, Google 'Wing Files'
Cheers all,
mcdhu
'To minimize overall fuel consumption during flight, a low CI must be used. As the climb phase is fuel consuming, it is advantageous to minmize climb duration. This is achieved at the maximum rate climb speed. CI 0 gives IASecon which is Max Rate Climb Speed.'
It seems to work out most times about 270KIAS in the A319.
For the above publication, Google 'Wing Files'
Cheers all,
mcdhu
Join Date: Mar 2000
Location: Sunrise Senior Living
Posts: 1,338
Likes: 0
Received 0 Likes
on
0 Posts
Yup, found it. FCTM 2.060 P3 of 5: ''The speed to achieve max rate ...........lies between ECON climb speed and green dot. As there is no indication of this speed on the PFD, a good rule of thumb is to use turb speed to achieve max rate.'
Cheers,
mcdhu
Cheers,
mcdhu
