Va Vs Vno
- Thread starter cocolos
- Start date
I will take a stab.
Va - design maneuvering speed. Max IAS at a given weight that full abrupt deflection of control surfaces will not cause structural damage. Aircraft will stall first.
Vs - Stall speed or minimum steady flight IAS speed that the aircraft is still controllable. (Vs1 and Vs0 are the stall speeds at certain configurations, simply clean and dirty)
Vno - Maximum IAS for normal operations. Generally the green arc on light aircraft.
I suspect you can Google these terms.
Va - design maneuvering speed. Max IAS at a given weight that full abrupt deflection of control surfaces will not cause structural damage. Aircraft will stall first.
Vs - Stall speed or minimum steady flight IAS speed that the aircraft is still controllable. (Vs1 and Vs0 are the stall speeds at certain configurations, simply clean and dirty)
Vno - Maximum IAS for normal operations. Generally the green arc on light aircraft.
I suspect you can Google these terms.
cocolos
Pre-takeoff checklist
So Vno is the limit for the ailerons and the rudder?
airguy
Cleared for Takeoff
Technically speaking, I don't think any manufacturer has listed a max speed for full deflection of ailerons or rudder. For decades Va was assumed to mean all control surfaces - but after AA587 that changed.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
Va is the maximum speed the aircraft can be stalled without exceeding the limit load factor (3.8g for normal category airplanes).
Vno is based on the maximum speed at which the aircraft can encounter a 50fps vertical gust and not exceed the limit load factor.
Vno is based on the maximum speed at which the aircraft can encounter a 50fps vertical gust and not exceed the limit load factor.
cocolos
Pre-takeoff checklist
Do you have a reference for this?
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
14 CFR §§ 23.333, 23.335, and 23.1505
PilotAlan
Pattern Altitude
- Joined
- Sep 26, 2009
- Messages
- 1,775
- Display Name
Display name:
PilotAlan
gismo
Touchdown! Greaser!
Sorry Captain, but that's not quite correct. Part 23 and 25 require proof that full and sudden deflection of rudder, aileron, or elevator (one at a time) doesn't cause permanent deformation of critical components at or below Va. The AA587 accident brought to light the fact (already clear in the certification rules but not well known in the general pilot population) that this doesn't include repeated and/or alternating control deflections and that's true for all three axes as well.
gismo
Touchdown! Greaser!
Yes and there are even more specifics than that. The deflection has to occur when the initial motion about the affected axis is zero and static IIRC.
warthog1984
Cleared for Takeoff
- Joined
- Jul 22, 2013
- Messages
- 1,447
- Location
- Chicagoan exiled to California
- Display Name
Display name:
LanCA'r
Not quite. Va (manuevering speed) is the speed at which the airplane cannot exceed structural load factors before stalling, given a single full and abrupt deflection of one axis control.
In other words, above Va you can still stall the plane safely; below Va any one input (besides CFIT) is physically incapable of permanently damaging the plane since it will stall first and therefore relieve the loading. steep turns and such are thus generally made below Va.
Vno is the "clear air" limit speed above which strong turbulence or specified strong gust is capable of damaging the plane.
So Va protects against pilot error, Vno guards against turbulence. The one exception is that for really strong turbulence I would drop below Va, just in case.
Last edited:
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
If you attempt to stall the aircraft above Va, you will exceed the limit load factor. I don't consider that very "safe".