ATCme
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What Are The Different Vs (V1 V2) On Takeoffs?

Wed Dec 28, 2005 2:44 pm

I may risk sounding stupid here, but I'm not a pilot. What are the Vs on takeoff. Like V1 V2 V3 etc. I'm not looking for specific numbers, but an explanation of what they are and represent. I wish I didn't have to ask, and I tried searching the tech-ops category for this. Sorry, but can anyone help?

ATCme
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Matt72033
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Wed Dec 28, 2005 6:36 pm

v1 is the first speed you'll reach. if you have a major failure, say an engine, before v1 the TP will be aborted, after V1 you must take off

VR is the speed at which the you rotate

and i believe V2 is the speed ay which you will climb, not sure on the exact description for that one! im sure someone else will give a more detailed explanation!
 
sudden
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Wed Dec 28, 2005 8:02 pm

Quoting ATCme (Thread starter):
I may risk sounding stupid here, but I'm not a pilot.

There are no such thing as stupid questions, and the majority of members here are not pilots.

V1
Rotate
V2
(V3)
are all decision speeds.

A typical senario during the T/O roll would be
80 knots- abort or continue t/o roll.
V1- at this speed you must go on and T/O as you would not have enough time to break without overshoot the rwy.
.
Rotate- the speed when you lift the nose to start your climb.
V2- climb out speed.
V3- not even sure if this one is used anymore.

Some of our tech. guys or pilots can most likely give you more in depth answer on the decision speeds.

Happy holidays!

Aim for the sky!
Sudden

[Edited 2005-12-28 12:04:35]

[Edited 2005-12-28 12:05:44]

Sorry for the edits but saw typos and mistakes made in my post.

[Edited 2005-12-28 12:19:41]
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Woodreau
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Wed Dec 28, 2005 10:05 pm

These speeds are defined in FAR 25 for transport category aircraft.

V1 is the takeoff decision speed - if an engine failure occurs below this speed you abort or reject the takeoff. If it occurs above this speed you continue the takeoff.

Vr is the rotation speed - where the nose gear is raised off the runway surface, but must allow the aircraft to accelerate to V2 before the aircraft reaches 35ft above the takeoff surface.

V2 is the takeoff safety speed - this minimum speed must be reached before the aircraft reaches 35ft above the takeoff surface with one engine inoperative. It guarantees a specific climb gradient up to 1500ft for obstacle clearance. From the time the landing gear is retracted until 400ft (second takeoff segment), it guarantees a 2.4%, 2.7%, and 3.0% climb gradient for 2-, 3-, and 4-engine airplanes. Above 400ft (final takeoff segment) to 1500ft the climb gradients are 1.2%, 1.5%, and 1.7% for 2-, 3-, and 4-engine airplanes.

Vfto - the minimum speed for the enroute climb above 1500ft until the aircraft reaches a cruise altitude.
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sudden
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Wed Dec 28, 2005 10:37 pm

Thanks for the more in depth clarification.

Is the V3 call out even used anymore? I heard that it was used before, but these days I am not sure.
Anyone that can clarify this?

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Starlionblue
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Wed Dec 28, 2005 10:59 pm

As Sudden points out, 80 knots is also a significant call.

You can abort all the way up to V1, but in practice the decision speed is normally split in two.

Up to 80 knots you will abort for anything.
Between 80 knots and V1 you only abort for engine failure, fire and other serious problems.
Above V1 you take off unless you have serious doubts about the ability of the plane to sustain flight.

The reason for the 80 knots->V1 interval is as follows: While it is possible to stop, it's not entirely risk free. Braking that hard may mean blowing the tires and so forth, maybe prompting a slide evacuation. So if the malfunction is minor, you would keep going.

Another reason for the 80 knot call is that on planes with only one nosewheel tiller (such as the MD-80) this is the point where the Captain lets go of the tiller if the F/O is flying.
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ATCme
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 8:13 am

Thanks so much! I don't know if V3 even exists, so don't worry about it Sudden, I just thought it would be since there is a V1 and a V2.

Quoting Starlionblue (Reply 5):
Another reason for the 80 knot call is that on planes with only one nosewheel tiller (such as the MD-80) this is the point where the Captain lets go of the tiller if the F/O is flying.

Since you brought up the tiller, what exactly is the difference between the rudder pedals and the tiller and what exactly is the tiller? Thanks again!
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Matt72033
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 9:08 am

rudder pedals will only give u up to 7 degrees nosewheel steering, the tiller will go up to more like 70 degrees!

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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 9:50 am

At different airports is the V1 speed different like at EDW Edwards air force base with a 737 would the V1 speed be different that the V1 speed of a 737 taking off from SNA. Because you said V1 is where if there is a failure you cannot abort takeoff so at an acceptionally long runway could the V1 speed be hire? Nice information guys  Smile. Also is there a certain technical calculation to determine V1 and V2 Speeds?
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Qantas744er
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 10:22 am

Well nowadays in modern aicraft like the 747-400,777,767,757,717 and airbus models, the FMC decides the speed, regarding altitude, temperature flap setting weight etc. So all the pilot has to do is choose the flap setting and the following V1 VR V2 will automatically show up.

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Starlionblue
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 11:02 am

Quoting Matt72033 (Reply 7):
rudder pedals will only give u up to 7 degrees nosewheel steering, the tiller will go up to more like 70 degrees!

Indeed. The pedals are mostly useful on the runway, not turning corners during while taxiing. Also IIRC some older airliners don't steer the nosewheel at all through the pedals so you have to use the tiller on the runway until the rudder starts to bite. But I could have that backwards.

[Edited 2005-12-29 03:02:41]
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SlamClick
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 11:20 am

Quoting AmericanAirFan (Reply 8):
At different airports is the V1 speed different like at EDW Edwards air force base with a 737 would the V1 speed be different that the V1 speed of a 737 taking off from SNA. Because you said V1 is where if there is a failure you cannot abort takeoff so at an acceptionally long runway could the V1 speed be hire?



In no case will V1 be higher than VR it doesn't matter how long the runway. Some aircraft have set all three speeds at the same point, so that at V1 you are also at rotate speed. Most companies now call V1 five knots below the actual speed to give recognition time.

Runway length (ability to stop in the remaining distance) is only one of several things that drive V1 for a given weight and flap setting. There are some lengthy explanations of these things in other older threads here in Tech/Ops. I'm too lazy to write another tonight but check back a couple months ago. You should find more information than you can use.
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 11:27 am

As you can see here http://www.hilmerby.com/dc9/d9_takeoff.html, Stellan Hilmerby includes the 80 knot handoff in the DC-9 takeoff procedure. As you can also see in the text, the F28 has no pedal steering at all. So the tiller becomes essential all the way up to rudder effectiveness (VMCsomething).
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 4:12 pm

Quoting ATCme (Reply 6):
Since you brought up the tiller, what exactly is the difference between the rudder pedals and the tiller and what exactly is the tiller

http://rds.yahoo.com/S=96062883/K=737+tiller/v=2/SID=w/l=IVS/SIG=11rqlj5v8/EXP=1135926451/*-http%3A//www.b737.org.uk/captsidewall.jpg
On the B737 Rudder pedals steering is upto 7 deg.With Tiller its 78 deg.
Tiller is a Steering wheel.Located mainly on the LH side,at times on both sides.[We could start a debate on that]  Smile
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sudden
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 7:34 pm

Quoting ATCme (Thread starter):
ATCme

Welcome to A,net by the way.
Nice to see some young, no offense, people taking part of this forum.

Aim for the sky!
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Thu Dec 29, 2005 7:53 pm

Quoting Sudden (Reply 14):
Welcome to A,net by the way.
Nice to see some young, no offense, people taking part of this forum.

Nice to see an ATC Fan too.
regds
MEL
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ATCme
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Sat Dec 31, 2005 8:35 am

Hey thanks Sudden and MEL for the welcome. And a few things to you MEL, I'd be willing to start a debate on it even though I have no clue (in-depth knowledge) of what we're talking about. And the second thing is, Are you also interested in ATC?

Have fun, all, and don't get too rowdy bringing in the new year!

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ATCme
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Sat Dec 31, 2005 9:15 am

Sorry, but I can't edit my above post for some reason, so here goes.

I'd like to ask a few more V questions. What are the Vs on landing? And what does the V stand for, Velocity?

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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Sat Dec 31, 2005 9:47 am

Quoting ATCme (Reply 17):
Sorry, but I can't edit my above post for some reason, so here goes

There's a 30 minute limit.

Quoting ATCme (Reply 17):
What are the Vs on landing?

I know theres Vref, which is reference, but I'll leave it to the pilots to give you an exact definition.

Quoting ATCme (Reply 17):
And what does the V stand for, Velocity?

Velocity indeed. Although shouldn't it be speed since no directional component is involved (unless it's in the direction of flight)? If I remember my middle school physics correctly velocity is a vector and speed is a scalar.
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ATCme
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Tue Jan 03, 2006 4:38 am

Quoting Starlionblue (Reply 18):
I know there's Vref, which is reference

Reference to what? and Are there any other Vs on landing? Thanks in advance.

So, most taxiing is done with the tiller? and What is the smallest aircraft that uses a tiller instead of rudder petals? Because I've flown a Cessna 1X2 (172, or 182, can't remember) and I was told to use the rudder petals and didn't see a tiller looking thing.
Thanks again

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Matt72033
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Tue Jan 03, 2006 4:47 am

Quoting Starlionblue (Reply 18):
Velocity indeed. Although shouldn't it be speed since no directional component is involved (unless it's in the direction of flight)? If I remember my middle school physics correctly velocity is a vector and speed is a scalar.

but you do have a direction dont you? forward? lol iu dunno im just guessing here!

Quoting ATCme (Reply 19):
So, most taxiing is done with the tiller?

yeah pretty much all taxying is done with the tiller, pedals are just used to keep the nosewheel on the runway centreline!
 
Fly2HMO
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Tue Jan 03, 2006 4:54 am

Quoting ATCme (Reply 19):
Because I've flown a Cessna 1X2 (172, or 182, can't remember) and I was told to use the rudder petals and didn't see a tiller looking thing.

Partly for system simplicity, and there's no point having "power stearing" in something so small and light. At least that's my theory  

The Citation XLS is steared fully by the pedals though...

[Edited 2006-01-02 20:56:29]
 
7E7Fan
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Tue Jan 03, 2006 5:20 am

Quoting ATCme (Reply 17):
I'd like to ask a few more V questions. What are the Vs on landing? And what does the V stand for, Velocity?

One quite important V to remember is Vmax or in other words max maneuvering speed at a certain configuration. If you exceed that you probably won't break things initially but you most definitely will have to buy your mechanics a keg of beer as they have to work overtime to check everything for sign of stress-damage.  banghead   bigthumbsup  However, if you exceed Vne or Never Exceed Speed then you'd better have a parachute handy  Smile

Some other more or less interesting ones can be found here: http://www.aviationboom.com/terms/vspeeds.shtml

/Mike
 
SlamClick
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Tue Jan 03, 2006 5:55 am

Quoting ATCme (Reply 19):
What is the smallest aircraft that uses a tiller instead of rudder petals?

The smallest I've seen is the Embraer Xingu. It is about a six (or xix Smile) place twin turboprop that I always thought resembled a Beech Duke on steroids.

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SlamClick
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Tue Jan 03, 2006 6:15 am

Quoting ATCme (Reply 19):
Reference to what? and Are there any other Vs on landing? Thanks in advance.

Reference from actually. The approach speed you will fly is in reference to the "reference" speed.

VREF is normally 1.3 VSO.

VS is stalling speed, the "O" makes it "in the landing configuration" so VSO is the stalling speed, or minimum steady flight speed in the landing configuration. VREF being 1.3 times that gives you a 30% margin above stalling speed.

To that speed we might add a wind protection increment; typically one half the steady wind speed plus all of the gust spread up to a predetermined maximum.

This would give us an approach speed, which some operators will actually call VAPP.

The actual approach speed is fairly close to V2 for your weight. Referring to a performance chart here for one jet I flew I can give you some actual numbers: If we are making an approach and our VREF at flaps 40 is 134 knots, the takeoff V2 for that same gross weight happens to be 139. This means that if we had, say, a ten knot wind additive making our approach speed 144 and we had to go missed-approach, or reject the landing we are already at or above V2 and we verify a positive rate of climb we can safely start pulling the gear up and the flaps up to a takeoff or go-around setting.

By the way, at the same weight, our best single-engine climb speed from this chart is 210 knots and minimum maneuver speed is 201. These are all right there in front of us either on a flip card or on-screen.
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Mir
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Tue Jan 03, 2006 10:45 pm

The V-speeds I have to know for the Piper Warrior:

Vso - 44kias (stall speed, flaps fully out)
Vs - 50kias (stall speed in clean configuration)
Vx - 63kias (best angle of climb speed - what you want to use if you need to clear an obstacle at the end of the runway)
Vg - 73kias (best glide speed)
Vy - 79kias (best rate of climb speed - what you generally use for climbs)
Va - 88kias (maneuvering speed at lowest possible weight)
Vfe - 103kias (maximum speed with flaps extended)
Va - 111kias (manuevering speed at max gross weight)
Vno - 126kias (upper limit of normal operating range - exceed only in smooth air, without any sudden control inputs, and with extreme caution)
Vne - 160kias (redline - never exceed)

I've never seen a published Vref for the Warrior, but I generally use 70kias as the reference, and add half the gust factor if there is one. The speed at which one should be over the threshold and the speed at touchdown are obtained from a performance chart, and are weight specific (though they're most often going to be 60kias over the threshold and 40kias on touchdown). The same can be said for rotation speed and initial climb speed (usually 48kias and 53kias, respectively).

-Mir
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Logan22L
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Wed Jan 04, 2006 5:41 am

Quoting Matt72033 (Reply 20):
Quoting Starlionblue (Reply 18):
Velocity indeed. Although shouldn't it be speed since no directional component is involved (unless it's in the direction of flight)? If I remember my middle school physics correctly velocity is a vector and speed is a scalar.

but you do have a direction dont you? forward? lol iu dunno im just guessing here!

Good guess, Matt. Indeed speed is scalar and velocity is a vector quantity, but the inherent change of position associated with a VR, say, is assumed to be based on the position of the aircraft at rotation relative to its position at the start of take-off roll.
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ATCme
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Sat Jan 07, 2006 12:28 pm

Hey, thanks guys/gals. I like the link 7E7fan. Also, thanks Slamclick for the techy explanation, although with how busy I've been I'm too tired to understand it right now, plus thanks for the only example of the smallest plane with a tiller.

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cedarjet
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RE: What Are The Different Vs (V1 V2) On Takeoffs?

Mon Jan 09, 2006 10:36 pm

This has probably been explained but in shorthand, V2 is the minimum climb speed with an engine out with the flaps etc set in the takeoff configuration.

Btw the AA DC10 that crashed in Chicago after takeoff was indirectly related to V2. Basically the number one engine came off it's mounting as they reached VR, as it parted company with the wing it flipped over the top of the wing and damaged to the hydraulics, which caused the leading edge slats to retract ON THE LEFT WING ONLY. Which meant that the stall speed for that wing was higher that on the right wing, where the slats were still extended. The aircraft rotated and the pilot - correctly - started climbing at V2. Unfortunately the stall speed of the wing with the slats retracted was HIGHER than V2, so the left wing stalled and the plane rolled upside down and crashed. If the stall warning system had functioned, the pilot may have understood what the problem was and accelerated. Unfortunately the stall warning system was either damaged along with the hydraulics when the engine seperated, or it was u/s and not on the Minimum Equipment List (the list of technical faults that cannot be deferred til the next time the plane goes into the hanger).
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