Ferram aerospace research11/4/2023 To mantain level flight, they will produce downforce to counteract the nose-down moment due to the wing so, they create a small aerodynamic penalty. The "conventional" tailplanes, placed behind the wing, have a stabilizing effect. Special care should be taken for aircraft that have a large percentage of weight in fuel, or that drop cargo during flight: if the center of mass moves significantly, stability characteristics could be altered drastically. Also, the strong nose-down tendency might actually overpower the pitch controls, making it impossible to raise the nose over some angle and, in extreme cases, sending the aircraft into an unrecoverable dive. a very aft center of lift) is not without drawbacks, though: a very stable aircraft will have, by definition, sluggish controls. Similar considerations can be made for the yaw axis.Ī high stability margin (i.e. Were the CoL to be forwards of the CoM, a slight pitch-up generating higher lift would tend to raise the nose higher, generating still higher lift, and the positive feedback if unchecked would very rapidly flip the aircraft on its back. This is negative feedback, the basis of stability. In level flight, this nose-down tendency is exactly counteracted by the elevators: when pilot input, or an external disturbance, increases the pitch angle and thus lift, the downward moment will increase, and vice versa: the aircraft resists changes to its pitch attitude. of mass, the overall lift from its surfaces causes a nose-down moment: an increase in lift will act to dive the airplane. Details on static stabilityĪerodynamic forces will tend to rotate an aircraft around its center of mass. (This paragraph might become outdated in the future, if ASAS becomes moddable and Ferram can adapt it to FAR). High speed operation of ASAS in FAR will cause oscillations. With stock aerodynamics, the ASAS is actually sometimes capable to make unstable aircraft (barely) flyable: unfortunately, ASAS doesn't work correctly under FAR, since it doesn't account for realistic deflection times of the control surfaces. Statically unstable aircraft are almost always unflyable in KSP in the real world, computer control and quick acting control surfaces can actively stabilize such designs, but they remain rare. This is referred to as neutral stability or marginal stability.Īn aircraft must have its center of lift behind the center of mass to be statically stable. It will also not roll any further away from the initial state, so it is not statically unstable. If the ball is displaced in either direction, it will not return to its initial state, so it is not statically stable. This is an example of a system that is statically unstable.įinally, consider a ball that is placed on top of a flat table. It will gain speed and roll off of the mound. If the ball is displaced in either direction, it will not return to its initial state. This ball is also in equilibrium, but it is not stable. Now consider a ball that, instead of being placed inside of a bowl, is placed on top of a mound. This is an example of a system that is statically stable. If the ball is displaced in either direction, the ball will want to return to its initial position at the bottom of the bowl. For example, consider a ball inside of a bowl, pictured below. Static StabilityĪs mentioned above, static stability is the tendency of a system to return to equilibrium when disturbed. In other words, if nothing touches something that is in equilibrium it will not move. EquilibriumĮquilibrium is a state that, if undisturbed, will not change. Each of these types of stability is important to consider when designing airplanes and rockets with FAR installed. Dynamic stability is what happens to the system after it has been disturbed from equilibrium. Static stability is the tendency for a system to, when disturbed from equilibrium, return to equilibrium. There are two primary concepts of stability: static stability and dynamic stability. In order to understand these tools, one must first understand the concept of stability in the context of airplanes and rockets. Many of the tools in Ferram Aerospace Research (FAR) deal with the concept of stability.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |