V2 Speed - Definition?
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The airspeed an aircraft is at 35 feet on Takeoff.
Why is it there? It is at which speed, following an engine failure at V1, the aircraft must be capable of climbing and retracting the gear.
That's the concise version!
Why is it there? It is at which speed, following an engine failure at V1, the aircraft must be capable of climbing and retracting the gear.
That's the concise version!
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It's the speed at wich an aircraft must be when arriving at screen height to be able to continue climb on one engine in take off climb configuration.
Screen height can be lower or higher than 35 ft depending on conditions and type of aircraft....
Screen height can be lower or higher than 35 ft depending on conditions and type of aircraft....
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I seem to recall a definition of 'Minimum free air safety speed', ie, the lowest speed in TO configuration that you can suffer a worst case engine failure and still retain directional control. I don't have my 'Handling the Big Jets' tome (good one DP Davies, RIP) to look up.
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The Interview Answer
V2, the Take Off Safety Speed, is the lowest speed at which the aircraft complies with the handling criteria associated with climb after take off, following the failure of an engine.
V2 is also defined as the target speed to be attained at the screen height with one engine inoperative and is maintained to the point where acceleration to Flap Retraction Speed is initiated.
V2 is also defined as the target speed to be attained at the screen height with one engine inoperative and is maintained to the point where acceleration to Flap Retraction Speed is initiated.
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Crack
You've got to stop smoking that stuff mate! Perhaps your time with Iosopata has confused you even more on the green & gold island..? The words INITIATED and ATTAINED were both used correctly, in the correct places and I've personally checked my thesis to confirm that! To answer your question: Vr comes between those two along with a possible host of other performance dependant speeds. Cut back on the pints mate, you can see where it's got me and it's not pretty ... 
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TAKEOFF safety speed.
Yes, V2 is thus.
Some with more distant memories (and experience) will recall that all piston engine powered transports, as well as many turboprops, attained V2 prior to rotation...ie; while still on the runway.
In addition, the screen height was fifty feet, not 35.
The change made for transport jets was made to CAR4b (leaving aside the Comet and the ARB fiasco attached thereto) for one very simple reason...V2 while still groundbound, and the 50 foot screen height were absolutely not achieveable in the early underpowered jets of yesteryear, without excessive speeds (and the associated tire problems)...not to mention the large runway requirements (length) attached thereto.
And yes, speaking BOEING jets here.
Specifically the early -121 series 707's
A heap 'o cr@p, if there ever were any...for sure.
Yes, V2 is thus.
Some with more distant memories (and experience) will recall that all piston engine powered transports, as well as many turboprops, attained V2 prior to rotation...ie; while still on the runway.
In addition, the screen height was fifty feet, not 35.
The change made for transport jets was made to CAR4b (leaving aside the Comet and the ARB fiasco attached thereto) for one very simple reason...V2 while still groundbound, and the 50 foot screen height were absolutely not achieveable in the early underpowered jets of yesteryear, without excessive speeds (and the associated tire problems)...not to mention the large runway requirements (length) attached thereto.
And yes, speaking BOEING jets here.
Specifically the early -121 series 707's
A heap 'o cr@p, if there ever were any...for sure.
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V2-green & gold.
126.9: Green & Gold, Green & Gold???????you did say Tarawa?.
Your Thesis, WHO marked it?
Maybe you could point out to ALL of us,just where V2 begins and ends, and how do you get there.
Initiated Vs Attained.
411A,747FOCAL,& BOAC,love you guys.
Now I will go and have another pint mate?and you where never pretty.
Your Thesis, WHO marked it?
Maybe you could point out to ALL of us,just where V2 begins and ends, and how do you get there.
Initiated Vs Attained.
411A,747FOCAL,& BOAC,love you guys.
Now I will go and have another pint mate?and you where never pretty.
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Crack
1. Green & Gold - YES! Vic Bitter = Green & XXXX = Gold! 
2. UNSW - Sydney.
3. V2 begins and ends at V2 for any particular departure. Any deviation from the SELECTED V2, is a V2 plus or V2 minus deviation. Considering that V2 is the speed to which the aircraft, with one engine inop, must accelerate after rotation at Vr and lifting of at Vlof appropriate to the prevailing conditions, then V2 selection may begin at V2min which is the lowest speed that V2 may be in any ambient conditions or any configuration. In terms of CAS V2min may not be less than:
i) 1.2 Vs for:
a) Two and three-engined turbo-prop a/c and,
b) Turbo-jet a/c without provisions for obtaining a significant reduction in the one engine inop stalling speed.
ii) 1.15Vs for:
a) Four-engined turbo-prop a/c and
b) Turbo-jet a/c having provisions for obtaining a significant reduction in the one engine inop stalling speed.
iii) 1.10Vmc. JAR 25.107(b)
V2max (if you will) may be selected under the correct prevailing conditions, and would then be, V2 at Flap 0 taking into account all of the above: therefore the CONFIGURATION criteria is stated. It is of course worth bearing in mind that regardless of which V2 is selected for a particular departure, it needs to meet the above criteria AND then remains V2 for that take-off.
4. Once Flap retraction is commenced, the acceleration segment (and the basic principles of flight on most large aircraft) does not allow for V2 to be maintained. Therefore, V2 is also defined as the target speed to be attained at the screen height with one engine inoperative and is maintained to the point where acceleration to Flap Retraction Speed is initiated.
5. It is nice to see some male-bonding come out of the closet so openly!
6. On this point you are absolutely correct!
2. UNSW - Sydney.
3. V2 begins and ends at V2 for any particular departure. Any deviation from the SELECTED V2, is a V2 plus or V2 minus deviation. Considering that V2 is the speed to which the aircraft, with one engine inop, must accelerate after rotation at Vr and lifting of at Vlof appropriate to the prevailing conditions, then V2 selection may begin at V2min which is the lowest speed that V2 may be in any ambient conditions or any configuration. In terms of CAS V2min may not be less than:
i) 1.2 Vs for:
a) Two and three-engined turbo-prop a/c and,
b) Turbo-jet a/c without provisions for obtaining a significant reduction in the one engine inop stalling speed.
ii) 1.15Vs for:
a) Four-engined turbo-prop a/c and
b) Turbo-jet a/c having provisions for obtaining a significant reduction in the one engine inop stalling speed.
iii) 1.10Vmc. JAR 25.107(b)
V2max (if you will) may be selected under the correct prevailing conditions, and would then be, V2 at Flap 0 taking into account all of the above: therefore the CONFIGURATION criteria is stated. It is of course worth bearing in mind that regardless of which V2 is selected for a particular departure, it needs to meet the above criteria AND then remains V2 for that take-off.
4. Once Flap retraction is commenced, the acceleration segment (and the basic principles of flight on most large aircraft) does not allow for V2 to be maintained. Therefore, V2 is also defined as the target speed to be attained at the screen height with one engine inoperative and is maintained to the point where acceleration to Flap Retraction Speed is initiated.
5. It is nice to see some male-bonding come out of the closet so openly!
6. On this point you are absolutely correct!
Moderator
minimum unstick speed .... absolute minimum speed at which the aircraft can be dragged off the ground ... tests normally done with a something suitable bolted to the tail ... lots of sparks and scraping noises ...
Have a look at this set of slides ... one shows a demo on 727.
Have a look at this set of slides ... one shows a demo on 727.
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Vmu:
Minimum Unstick: The minimum demonstrated speed at which it is possible for the aircraft to become airborne.
Screen Height:
The minimum height to be achieved by the aircraft over the end of the take off distance available.
Props: 50 feet
Jets Dry: 35 feet
Jets Wet: 15 feet
By the way, What does this mean?
"without provisions for obtaining a significant reduction in the one engine inop stalling speed"
Minimum Unstick: The minimum demonstrated speed at which it is possible for the aircraft to become airborne.
Screen Height:
The minimum height to be achieved by the aircraft over the end of the take off distance available.
Props: 50 feet
Jets Dry: 35 feet
Jets Wet: 15 feet
By the way, What does this mean?
"without provisions for obtaining a significant reduction in the one engine inop stalling speed"