By increasing the mass of the airplane, you decrease the overall acceleration that results from any overall force. Of course, if you increase the mass of cargo, it increases the stress on the cargo-compartment floor — but it decreases the stress on unrelated components such as engine mounts, because the acceleration is less.
Finally, we should note that there are two different concepts that, loosely speaking, are called maneuvering speeds. Denker, John S. The discussion above pertains to the maneuvering speed limitation, i. The reader will also note that these values fit the general relationship given at the beginning of this answer.
As the maneuvering speed depends on the load factor and the stall speed, it depends on the weight of the aircraft which decides the stall speed. It is basically a structural limit. Another thing to note is that the aircraft can sustain structural failure even below maneuvering speed when multiple large control inputs are given. Wikipedia says this is valid only when a single control surface is maximally deflected, but really the regulations try to make sure that any combination of single control inputs is safe.
To determine the structural load, one must know the mass of all non-lift-creating parts. Fuel in the wing tanks does not count, as it is carried by the lift created right around it and does not increase the wing root bending moment. Consequently, the stresses can grow above those used for sizing the structure.
So I went and watched the tutorial. Va is a speed limit, above where the airplane will exceed its G load limit before it stalls if abruptly manuvered. How does weight factor in? The heavier plane would need higher speed than a lighter plane to reach Va AOA limit in straight and level flight. Too small an AOA sets you up for exceeding G load limits in an event such as severe turbulence.
Properly working AOA sensors are valuable instruments for this application, as well as the airspeed indicator. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why does maneuvering speed vary with weight? Ask Question. Asked 6 years, 3 months ago. Welcome Guest. Sign in or Signup. John D Collins on Apr 20, Va is related to the clean stall speed.
It is the stall speed times the square root of the maximum load factor. The stall increases with the square root of the load factor. So if you are pulling 4 G, the stall speed doubles. Since the stall speed varies with weight and is higher for a higher weight, the Va goes up with higher weight by the square root of the ratio of the weights times the Va at a lighter weight.
Another way of looking at it is that the greater mass of a heavier aircraft is not moved as much by a gust than an aircraft with a lighter weight or mass, and therefore a gust induces less of a load on the structure at any speed. A is barely moved at all by turbulence that might be considered as heavy turbulence by a cessna and the pilot as well as the aircraft feel the additional difference in the load by a gust in the smaller and lighter aircraft.
Steve on Apr 20, All rights reserved. Skip to content. Quick links. Why does Va increase with weight?
Post by shurshot17 » Wed Apr 15, pm C lbs 97 va lbs 89 va lbs 80 va I tried to find the answer but the POH, ground up, ect gave me no answer to why Va increases with weight So I asked my instructor, got some crazy explanation that made no sense to me.. Appreciate it if someone could explain it on here Thanks, Shurshot. Re: Why does Va increase with weight?
Post by Oxi » Wed Apr 15, pm You may want to find a different instructor! I'm fairly certain that From The Ground Up will have it. Think of a Cessna and a going knots. They both pull up, the is a lot heavier and the G forces are going to put a lot more than a Which do you think will stall first?
Which do you think will have an easier time maneuvering? Post by Justjohn » Thu Apr 16, am It is simple but not often well understood and it certainly is not intuitive.
Maneuvering speed, or Va, is directly related to stall speed. Airplanes in the normal category are certified to 3. At manovering speed , under 3. Or, it supposed to anyways. Va varies with weight as stall speed varies with weight. The stall is a form of aerodynamic 'relief' if you will. In addition, the controls are rigged and built strong enough to withstand full and abrupt deflection at this speed. Flying is better than walking.
Walking is better than running. Running is better than crawling. All of these however, are better than extraction by a Med-Evac, even if this is technically a form of flying. The fuller one wallows around where as the empty one gets thrown around wildly. The accelration forces G are much higher on the empty one as it is tossed around more.
Now in an airplane we can stall. Stall speed increases with load G wether that be load in the plane or aerodynamic load. If your airplane is designed to pull 3.
Va allows you to calculate the maximum speed at which the wing will stall before exceeding the 3. Remember a stalled wing has no load, that's why we fall to our doom when we stall.
In turbulence, the choppy air loads the wings and when the wing stalls it is just a momentary thing to set off the horn and alarm the passengers. Clear as mud? Post by rob-air » Thu Apr 16, am C vs 44 kts lbs lbs X 4. Sally 's on take off lbs Sally also like to pull g's.
She could pull 5. The speed she wil stall reaching 4. Sally's Vs is less than 44kts, in fact it is close to 37 kts using the simple lift formula to find CLmax well sqrtr 4.
Post by cgzro » Thu Apr 16, am Imagine a car stopped and idling on the ice. On the passanger seat you place a bucket with water which you dont want to spill. However add enough weight to the car and at some point it cannot accellerate or turn or brake fast enough to spill the water.
Short story the lighter a car on ice the more accelleration it can inflict on things inside it. One weighs lbs, the other weighs lbs.
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