Vb Vr V2 Vx relationship

[herschel mcleod]

hi their is their any relationship between Vr Vb V2 and Vx of any type what so ever

[OsPi]

V1 Vr V2 Vx would make more sense, are you sure about Vb?

Vb is the design speed for maximum gust intensity.

[Pugilistic Animus]

Vr= 1.1 or 1,05 Vmu [minimum unstick speed--all engines] or at least 1.05 Vmca [min control speed in the air] 0r 1.10 Vs [stall speed power off] or a spped that allows V2 to be at least 1.1 Vmca or 1.2 Vms1 [min stall speed at specific Take off flap setting] ----

----V1 controls the accelerate stop distance

Vx = on a jet [L/D] max

Vb as said above max gust intensity

V1 Vr or V2 may be different than the minima above due to specific performance considerations such a V2 over speed schedules, V1 wet, V1max, Vr=V1 etc...

[aamandani]

V=0 – Velocity at lineup
VS – Stall Velocity (airspeed at which enough lift can be generated to remain airborne)
VMC – Minimum Controlled Airspeed with the critical engine inoperative
V1- Critical engine failure recognition speed. (> VMC)
VR – Rotation speed. (5% > VMC)
VMU – Minimum un-stick speed - the point at which the aircraft could take off if the maximum possible rotation angle were reached. This maximum angle would occur if the tail of the plane were to actually scrape the ground. (> VS) VLOF – Lift-off speed. Liftoff speed must be at least 10% greater than VMU when all engines are operating and 5% greater when one engine has failed. V2 – Takeoff safety speed must be reached at an altitude high enough to clear a given obstacle. For FAR 25 aircraft, the obstacle clearance height is 35 ft. The takeoff climb speed must be at least 20% greater than stall speed, VS, and 10% greater than VMC.

thts wat i learnt frm my aerodynamics class...i dnt rmr it though cz i hvnt strtd flying big airplanes wer i hve all thse v-speeds..still wrking on my comm..i hop tht helps..hve sme mre notess on tht if u need..safe flying..

[Pugilistic Animus]

Aamandani, it all still depends on the specific certification of the expanding on what i said above a little---


ONE WAY your to determine Vr= 1.10Vmu [as you wrote] when tail grounding isn't a factor and 1.05Vmu when it is but other criteria may apply and any one of the above minimum criteria previously stated may have been used to determine your V speeds....also Vr has to assure that under limiting critical cases that V2 is achieved OEI---at the correct fence or screen height---


---However for economic/safety considerations when a limiting scenario isn't encountered flexibilty is available in the V speed selection allowing a greater flexibilty in operations depending on specific company goals

and this particular discussion can really flare up :ouch:

[aamandani]

well u mst b right as ur also a proff of aeronautics..i still dnt hve enough experience wer i cn really tel alt of difference in thse v speeds..bt tnxx for tht info..rely helps..tc..safe flying..

[chornedsnorkack]

V=0 – Velocity at lineup

Well, stall speed is certainly airspeed. Therefore the velocity at lineup/brake release would not generally be zero, and it could be either positive or indeed negative.