In this figure, the rocket is initially stable, being in the same ideal situation as in Fig. 2A illustrates a rocket with the CP, CG locations reversed, that is, the CP is ahead of the CG. This force balances the force due to wind, and the rocket remains stable, with its flight path only slightly altered.įig. This change in angle of attack immediately generates a lift force, acting as shown (normal to the body) through the CP. The resultant of this pressure force acts through the CP, causing the rocket to rotate about its CG, changing slightly the angle of attack (alpha). 1B, a perturbing force is introduced, in this example, the force due to a gust of wind. The rocket is stable and accelerating with exclusively linear motion along the line of thrust. 1A, the rocket is shown during the powered flight This is an ideal state, with all the forces acting through the CG and no external (perturbing) forces present. This is because this principle is true for a body of any shape, not only for a finned rocket (for example, fireworks rockets don't have fins yet are stable bodies).
In this figure, the rocket is illustrated in a simplified form.
Foil placement diagrams free#
The importance of the location of CP relative to CG is apparent by considering a free body diagram of a rocket in flight.įigure 1 shows a stable rocket, with the CP aft of the CG. For a rocket that is to be stable in flight, this point must be aft of the CG by a certain amount. If you were to hold the rocket by grasping it with two fingers (such that it could pivot horizontally), the location where it would be perfectly balanced in the airflow is the location of the centre of pressure (it is somewhat more complicated, however, as the CP location varies with the angle of attack in this example, the angle of attack is 90 degrees). This is perhaps best visualized by imagining yourself holding the rocket outside the window of a moving car, however, holding it perpendicular to the airflow (e.g. The CP is similar, it is where the resultant force of aerodynamic pressure acts, or the aerodynamic balance point. This is important, because this is the point that the rocket would rotate about if it was spun end over end. It is the mass balance point of the rocket, that is, if the rocket was laid horizontal and balanced on a pencil, the CG is the location where the rocket balances. This begs the question - what exactly are the centre of gravity and the centre of pressure and why the importance of these? Fitting fins on a rocket serves to locate the centre of pressure aft of the CG. The problem here is that the rocket's centre of pressure (CP) would be forward of its centre of gravity (CG). If a typical amateur rocket was launched without fins, it would soon begin to tumble after leaving the launcher, due to the way that aerodynamic and other forces (such as wind) act upon the rocket, in relation to the forces that are exerted upon the rocket by the motor and by gravity. The purpose of putting fins on a rocket is to provide stability during flight, that is, to allow the rocket to maintain its orientation and intended flight path. Richard Nakka's Experimental Rocketry Web Site MUST RINSE HAIR THOROUGHLY.Richard Nakka's Experimental Rocketry Site Note: Careful with working with enlightener as it does not stop working until dry or washed out. If tone needed would be applied at the sink. Rinse the hair thoroughly before shampooing twice and conditioning once using Color Conserve Shampoo and PHinish Conditioner.ġ3. Once desired colour bring the guest to the sink to wash the hair out.ġ2. Wait for the enlightener to take effect as per developer time.ġ1. Do the next top section and finally do the last diamond shape diagonally.ġ0. Go back to the first side and complete the top section as per previous instructions.ĩ. Repeat these steps on the opposite side.Ĩ. Continue slicing and weaving the highlights diagonally following Diagram 1.ħ. Place foil underneath and apply enlightener. Slice the hair and weave desired look starting from the side closest to the eyes. Starting at the side, opposite of the dominant hand, is where to begin the highlights. The second colour bowl is used to place the colour brush in when not needed as to avoid an unnecessary mess.ĥ.
Once decided have guest gowned and section the hair into 5 sections according to Diagram 1.Ĥ. Before gowning the guest agree on the look desired.ģ. Before the guest arrives have the appropriate amount of foils separated.Ģ. Toner Formula (Optional Depending on Desired Result)ġ.Guest should be seated and caped with a towel underneath.
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