![]() ![]() Thermally small scale print fins won't like Mach 3. ![]() ![]() We hit a snag at interstage implosion L-1 multistage first HPR design. Make sure to flutter sim the tip as in reality that flutters first. We had professors b*tching how we obtained certain data points. They won't release an airfoil generator for data we had. NASA wouldn't publicly comment on airfoil data I obtained when questioned at SEDS. So, are my hunches right? Feedback is welcome.Īlready flew and designed supersonic airfoils for UTC SEDS 2017 USRC placed third. Higher speeds favor the thinner airfoils at speeds higher than Mach2, so it'll be 4%. Research on supersonic airplanes in the 70's seems to point to an optimal thickness of the airfoil between 4% and 6% of the length. Why not make a long thin supersonic fin with a Von Karman profile at front and back, like a Von Karman nose cone glued to a Von Karman tail cone, but then very long and thin? That might be pretty efficient. While different nose cones have advantages and disadvantages, the Von Karman profile is a good all-rounder, efficient at subsonic and upper supersonic speeds, somewhat less at transsonic speeds. What other shape do we use made from intersecting circular arcs? An Ogive nose cone!Īn ogive nose cone isn't the most efficient shape for supersonic flight, but there are a number of other choices, like the Von Karman nose cone based on research in fluid mechanics. The symmetric circular arc airfoil got me thinking. The idea is to reduce primary shock waves at the leading edge, and reduce the influence of secondary shock waves. The other cross section used in supersonic research is the symmetric circular arc airfoil, which also has sharp leading and trailing edges. The double wedge airfoil used with the NIKE sounding rocket is an example, but many rocketeers use a trapezoidal cross section, sharp at the leading and trailing edges, flat in the middle. Current wisdom seems to prefer sharp knife edge leading and trailing edges. While doing some research on supersonic profiles, I realized that laminar flow airfoils don't work because they produce a big shock wave at the leading edge. I've flown this kind of airfoil with success, printed from my 3D printer and reinforced with a layer of fiberglass. It also lets your rocket go higher (less drag). It's has about a 6% thickness to length at a 30% chord, and makes a fairly strong fin. For the tailoring process, it is found that the flutter Mach number increases more than 81% using as the Graphite/epoxy composite replaced the aluminium as the skin.This kind of airfoil is great for subsonic flight, where air stays in laminaar flow along the surface of the fin, and reduces turbulence and therefore drag. The investigation shows good agreement to the objective where the removal of weight for the High Modulus (HM) graphite/epoxy wing skin for the skin weight, clean wing and total wing with missile launcher external stores are 75.82%, 61.96% and 22.09%, respectively compared to the baseline aluminium wing model. As the optimization process is on-going, the flutter speed and the plate manufacturing thickness become the restriction in the wing weight reduction. In this paper, the objective of this tailoring process is to optimize the wing weight while maintaining the flutter boundaries, where the wing design adopted in this research has been analyzed at sea level. Technically, an optimization procedure that is utilizing the aeroelastic parameter as a constraint is called aeroelastic tailoring. In contrast, the structural weight could be reduced through the optimization process. The composite material such that graphite/epoxy gives high modulus compared to the metallic material such as aluminium where the structural flexibility could be improved. The application of composite material in aeroelasticity contributes to the changes in the expected flutter speed. This article offers an optimization procedure in designing much lighter supersonic wing by employing a composite structure by constraining the structural persistence due to flutter speed, a type of aeroelasticity failure. ![]()
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