Page 8 - Combined_26_OCR
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                  After considering-many different airfoil sections, it was decided to use a
                  GLARN-Y section for the rear deck airfoil and an 1IACA-OO12 section for the
                  vertical stabilizers. Both of these sections are considered to be quite
                  ancient having been used on many of the very early aircraft. Although lower
                  drag - laminar flow airfoils have been developed in recent years, the
                  expected surface roughness of the control surfaces on the race vehicles due
                  to dust and other particles and imperfections nullifies the advantage of
                  the more modern airfoils, ie. - surface roughness increases the drag of
                  laminar flow type airfoils to a level comparable to the more traditional
                  sections selected•
                  Figure 1 shows the fore and aft locations and approximate dimensions of the
                  recommended airfoil stabilizers. The stabilizers are placed as far from
                  the vehicle center line as practical to reduce the effects of the greenhouse
                  on the air flow at the stabilizers. Tuft studies on wind tunnel models
                  indicate the flow is relatively straight in this region. The high airfoil,
                  position was selected to maintain airfoil control in ’’drafting” situations by
                  placing the control surface above the relatively stagnant region between the two

                  Figures 2 and b shew the dimensional parameters for the two airfoil sections
                  while Figures 3 and 5 contain information on the sectional lift and drag coeffi­
                  cients. In both cases, the lift and drag coefficient curves have been
                  corrected for Reynolds Number and surface roughness effects at race speeds.
                  Aspect Ratios of both stabilizers and airfoils have been assumed to be 6 even
                  though the actual geometry of the recommended sections results in Aspect
                  Ratios of 2 and 6 for the stabilizers and airfoil respectively. This is
                  explained by the fact that the stabilizer to quarter panel and stabilizer
                  to airfoil junctures tend to modify the effective Aspect Ratios upwards by
                  some unknown amount because of the effects on tip vortices $ above Aspect
                  Ratios of 6, airfoil characteristics do not change markedly. Taper and sweep
                  corrections were also considered -for the stabilizers but were found to be
                  negligible. The interference effects between rear quarter and stabilizers
                  were also neglected because no theoretical solution was readily applicable .

                  Because the rear deck airfoil and the stabilizers are located at the rear of
                  the car a considerable distance from the tire to road contact points, the
                  moment arms tend to magnify the control effects at the road. Figure 6
                  illustrates the combined effects of the recommended aerodynamic handling
                  package at various vehicle body rake angles, yaw angles., and airfoil angles
                  of attack. All data is related to a base vehicle, namely the recommended
                  °F” Charger Race configuration discussed in reference 1. With the airfoil
                  set at -10° angle of attack, the airfcil-stabilizer combination increases
                  .axial force coefficient by .Oil; throughout the body rake schedule which means
                  that the lap speed of the vehicle, based on drag alone, will be. reduced by
                  approximately 1 MPH. In the process of reducing rear lift with the airfoil,
                  the front lift increases by approximately 1 pound for every k pounds of rear '
                  lift reduction. Thus, if a large front to rear lift differential is to be
                  maintained with the front lift essentially reduced to zero, the body rake
                  will have to be increased or a larger front spoiler employed. As in the
                  lift case, as the rear wheel side force is increased the front side force is
                  reduced, by approximately a h to 1 ratio. Although front and roar side force

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