PDF/ocr_dataset_1016.jsonl

{"citation_id": "19930082447", "source_url": "https://ntrs.nasa.gov/api/citations/19930082447/downloads/19930082447.pdf", "page_number": 14, "total_pages": 24, "image_filename": "19930082447_p14.jpg", "text": "12\nNACA TN No. 1775\n\nTABLE II - Concluded\nIMPACT-LOADS DATA FROM TESTS OF A PRISMATIC FLOAT\nWITH 40° ANGLE OF DEAD RISE - Concluded\n\n<!-- Table (115, 228, 912, 939) -->\n\\begin{tabular}{|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|}\n\\hline\n\\multirow{3}{*}{Run} & \\multicolumn{3}{c|}{At contact} & \\multirow{3}{*}{\\shortstack{Approach \\\\ parameter, \\\\ $\\kappa$}} & \\multicolumn{4}{c|}{At $z_{1_{max}}$} & \\multirow{3}{*}{\\shortstack{Time, $t$, \\\\ at chine \\\\ immersion \\\\ (sec)}} & \\multirow{3}{*}{\\shortstack{Time, $t$, \\\\ at bow \\\\ immersion \\\\ (sec)}} & \\multicolumn{3}{c|}{At $y_{max}$} & \\multicolumn{3}{c|}{At rebound} \\\\\n\\cline{2-4}\\cline{6-9}\\cline{12-14}\\cline{15-17}\n& $\\dot{y}_0$ & $\\ddot{x}_0$ & $\\gamma_0$ & & $t$ & $n_1g$ & $z_1$ & $\\dot{y}$ & & & $t$ & $y$ & $n_1g$ & $t$ & $\\dot{y}$ \\\\\n& (fps) & (fps) & (deg) & & (sec) & (g) & (ft) & (fps) & & & (sec) & (ft) & (g) & (sec) & (fps) \\\\\n\\hline\n\\multicolumn{17}{|c|}{$\\tau = 9^\\circ$} \\\\\n\\hline\n54 & 9.24 & 35.59 & 14.55 & 0.571 & 0.115 & 1.85 & 0.96 & 5.76 & None & None & 0.258 & 1.29 & 0.58 & 0.825 & -2.13 \\\\\n55 & 9.24 & 44.44 & 11.75 & .618 & .103 & 2.16 & .87 & 6.33 & -do- & .108 & .230 & 1.18 & .79 & .648 & -2.63 \\\\\n56 & 9.46 & 45.45 & 11.76 & .718 & .100 & 2.25 & .87 & 6.75 & -do- & .110 & .230 & 1.19 & .88 & .655 & -2.63 \\\\\n57 & 9.53 & 45.87 & 11.74 & .719 & .102 & 2.29 & .93 & 8.03 & -do- & .107 & .212 & 1.22 & .92 & .642 & -2.77 \\\\\n58 & 9.46 & 46.08 & 11.60 & .728 & .104 & 2.25 & .88 & 6.61 & -do- & .114 & .226 & 1.21 & .80 & .654 & -2.67 \\\\\n59 & 8.96 & 51.55 & 9.86 & .864 & .104 & 2.28 & .85 & 5.76 & -do- & .074 & .207 & 1.09 & 1.08 & .565 & -3.06 \\\\\n60 & 9.10 & 58.82 & 8.79 & .975 & .102 & 2.55 & .84 & 5.47 & -do- & .117 & .176 & 1.04 & 1.25 & .494 & -3.56 \\\\\n61 & 8.60 & 57.14 & 8.56 & 1.002 & .104 & 2.37 & .81 & 5.33 & -do- & .082 & .194 & 1.03 & 1.18 & .522 & -3.13 \\\\\n62 & 8.75 & 63.69 & 7.82 & 1.101 & .106 & 2.55 & .82 & 5.05 & -do- & .128 & .181 & .98 & 1.30 & .466 & -3.70 \\\\\n63 & 8.89 & 65.79 & 7.70 & 1.118 & .099 & 2.71 & .82 & 5.40 & -do- & .124 & .175 & .99 & 1.52 & .490 & -3.84 \\\\\n64 & 9.03 & 77.51 & 6.65 & 1.301 & .101 & 2.97 & .77 & 5.12 & -do- & None & .151 & .91 & 1.52 & .391 & -4.05 \\\\\n65 & 8.60 & 76.34 & 6.43 & 1.347 & .109 & 2.67 & .80 & 4.19 & -do- & -do- & .167 & .90 & 1.57 & .405 & -3.98 \\\\\n66 & 8.67 & 86.20 & 5.74 & 1.513 & --- & 3.27 & --- & 3.98 & -do- & -do- & --- & --- & 2.00 & .343 & -4.48 \\\\\n67 & 8.60 & 86.96 & 5.65 & 1.537 & .105 & 2.97 & .76 & 4.12 & -do- & -do- & .155 & .84 & 1.57 & .365 & -4.34 \\\\\n68 & 3.27 & 43.48 & 4.30 & 2.030 & .227 & .50 & .62 & 1.35 & -do- & -do- & .317 & .08 & .28 & .938 & -.50 \\\\\n69 & 3.12 & 44.64 & 4.00 & 2.185 & .218 & .45 & .54 & 1.49 & -do- & -do- & .318 & .61 & .25 & .902 & -.64 \\\\\n70 & 2.98 & 58.48 & 2.98 & 3.005 & .210 & .55 & .51 & 1.14 & -do- & -do- & .272 & .54 & .35 & .663 & -1.35 \\\\\n71 & 2.92 & 60.34 & 2.78 & 3.157 & .212 & .55 & .50 & 1.07 & -do- & -do- & .280 & .54 & .32 & .662 & -1.28 \\\\\n\\hline\n\\multicolumn{17}{|c|}{$\\tau = 12^\\circ$} \\\\\n\\hline\n72 & 9.46 & 23.15 & 22.23 & 0.454 & 0.130 & 1.65 & 1.14 & 6.26 & 0.201 & 0.145 & 0.339 & 1.63 & 0.41 & 1.202 & -0.92 \\\\\n73 & 7.96 & 23.04 & 19.06 & .545 & .129 & 1.23 & .95 & 5.83 & .297 & .174 & .344 & 1.47 & .35 & 1.145 & -1.42 \\\\\n74 & 9.53 & 29.67 & 17.81 & .590 & .130 & 1.86 & 1.09 & 5.83 & .202 & .146 & .270 & 1.47 & .63 & .905 & -1.85 \\\\\n75 & 9.10 & 30.03 & 16.45 & .628 & .117 & 1.71 & 1.02 & 6.19 & .153 & .149 & .278 & 1.43 & .50 & .870 & -2.13 \\\\\n76 & 8.11 & 30.12 & 15.07 & .712 & .130 & 1.47 & .92 & 5.62 & None & .207 & .280 & 1.29 & .50 & .897 & -1.78 \\\\\n77 & 9.46 & 39.84 & 13.36 & .813 & .115 & 2.17 & .99 & 6.04 & -do- & .192 & .237 & 1.28 & .85 & .642 & -2.77 \\\\\n78 & 9.24 & 39.84 & 13.06 & .813 & .115 & 2.16 & .93 & 5.76 & None & -do- & .225 & 1.20 & .96 & .628 & -3.06 \\\\\n79 & 7.75 & 39.53 & 11.09 & .994 & .140 & 1.65 & .94 & 4.34 & -do- & -do- & .240 & 1.12 & .80 & .650 & -2.77 \\\\\n80 & 7.96 & 40.98 & 10.99 & 1.004 & .139 & 1.73 & .94 & 4.48 & -do- & -do- & .229 & 1.10 & .87 & .632 & -2.99 \\\\\n81 & 4.45 & 22.83 & 10.06 & 1.103 & .247 & .43 & .85 & 2.06 & -do- & -do- & .413 & .08 & .15 & --- & --- \\\\\n82 & 9.39 & 56.18 & 9.49 & 1.173 & .120 & 2.64 & .95 & 4.19 & -do- & -do- & .183 & 1.08 & --- & No exit & No exit \\\\\n83 & 8.11 & 56.18 & 8.21 & 1.365 & .126 & 2.17 & .71 & 3.98 & -do- & -do- & .189 & .83 & 1.52 & .467 & -3.91 \\\\\n84 & 5.83 & 40.65 & 8.16 & 1.376 & .157 & 1.14 & .80 & 3.34 & -do- & -do- & .289 & .52 & .60 & .684 & -2.28 \\\\\n85 & 4.34 & 30.40 & 8.12 & 1.382 & .235 & .66 & .81 & 1.85 & -do- & -do- & .350 & .90 & .36 & 1.001 & -.71 \\\\\n86 & 9.53 & 69.44 & 7.81 & 1.439 & .105 & 3.24 & .86 & 4.76 & -do- & -do- & .155 & .97 & 2.05 & .372 & -4.98 \\\\\n87 & 9.03 & 68.03 & 7.56 & 1.489 & .105 & 2.97 & .81 & 4.91 & -do- & -do- & .160 & .93 & 1.25 & .378 & -4.62 \\\\\n88 & 7.75 & 68.49 & 6.46 & 1.753 & .118 & 2.33 & .76 & 3.91 & -do- & -do- & .170 & .85 & 1.43 & .402 & -4.12 \\\\\n89 & 7.61 & 68.49 & 6.34 & 1.787 & .121 & 2.32 & .78 & 3.41 & -do- & -do- & .171 & .85 & 1.48 & .391 & -4.12 \\\\\n90 & 4.34 & 40.98 & 6.05 & 1.876 & .194 & .75 & .70 & 2.06 & -do- & -do- & .289 & .79 & .58 & .730 & -1.56 \\\\\n91 & 3.06 & 29.33 & 5.96 & 1.905 & .260 & .40 & .71 & 1.49 & -do- & -do- & .392 & .77 & .20 & No exit & No exit \\\\\n92 & 9.24 & 90.09 & 5.86 & 1.938 & .104 & 3.68 & .76 & 4.27 & -do- & -do- & .137 & .81 & 2.98 & .304 & -5.40 \\\\\n93 & 5.76 & 56.50 & 5.82 & 1.952 & .150 & 1.38 & .72 & 2.77 & -do- & -do- & .210 & .81 & .96 & .504 & -2.99 \\\\\n94 & 9.10 & 89.29 & 5.82 & 1.952 & .099 & 3.57 & .73 & 4.41 & -do- & -do- & .139 & .81 & 3.10 & .304 & -5.33 \\\\\n95 & 3.98 & 39.37 & 5.77 & 1.969 & .200 & .65 & .67 & 1.85 & -do- & -do- & .299 & .78 & .40 & .750 & -1.64 \\\\\n96 & 8.75 & 91.00 & 5.49 & 2.073 & .104 & 3.57 & .76 & 3.56 & -do- & -do- & .134", "timestamp": "2026-07-22T04:41:19.905346+00:00"}
{"citation_id": "19930086151", "source_url": "https://ntrs.nasa.gov/api/citations/19930086151/downloads/19930086151.pdf", "page_number": 32, "total_pages": 34, "image_filename": "19930086151_p32.jpg", "text": "```markdown\n30\nNACA RM L9J28\n\nCONFIDENTIAL\n\n<!-- Image (85, 110, 842, 785) -->\n\nCONFIDENTIAL\n\nFigure 14.— Variation of estimated wing-tip helix angle $\\frac{pb}{2V}$ with total aileron deflection for the 45° sweptback complete wing. Aileron differential, 1:1.\n```", "timestamp": "2026-07-22T04:41:20.195286+00:00"}
{"citation_id": "19930082487", "source_url": "https://ntrs.nasa.gov/api/citations/19930082487/downloads/19930082487.pdf", "page_number": 11, "total_pages": 33, "image_filename": "19930082487_p11.jpg", "text": "NACA TN No. 1813\n\nThe experimental pressure distribution for each of the cases considered in figure 9 reveals that at Mach numbers above that of drag divergence the maximum local Mach number occurs near the airfoil crest. This phenomenon is probably characteristic of moderately thick airfoil sections only; but, for these cases, it suggests the possibility of predicting the peak pressure coefficient. In figure 10 the experimental local Mach number distribution over the NACA 23015 airfoil section at $2^\\circ$ angle of attack is shown for several free-stream Mach numbers greater than that of drag divergence. The Prandtl-Meyer theoretical Mach number distribution for this airfoil is shown for comparison; although, of course, this theory is not valid for a supersonic region of limited extent normal to the airfoil chord. It is seen that a close approximation to the experimental local Mach number distribution can be obtained by taking one-half of the Prandtl-Meyer Mach number increment per degree of surface turning. Figure 11 shows that, for the airfoil sections considered in figure 9, a useful approximation to the local Mach number at the airfoil crest for Mach numbers above that for drag divergence is obtained by using one-half the Mach number increment predicted by the Prandtl-Meyer theory. In these calculations the sonic point was assumed to be that at the drag-divergence Mach number.\n\nCONCLUDING REMARKS\n\nA good measure of the free-stream Mach number at which the abrupt supercritical drag rise begins has been shown to be that Mach number at which sonic local velocity occurs at the airfoil crest. This fact provides a method for calculating the drag-divergence Mach number. The method consists of determining the free-stream Mach number at which sonic velocity occurs at the airfoil crest by applying the Prandtl-Glauert compressibility factor to the low-speed pressure distribution. The usefulness of this method is demonstrated by comparing the calculated drag-divergence Mach number with that determined experimentally for a wide variety of airfoil shapes.\n\nThe mixed subsonic and supersonic flow fields which exist at supercritical speeds are extremely difficult to treat mathematically. The general considerations of this report are no substitute for such an analysis, but they do present a simplified picture of this complex type of flow which should be useful in planning further studies.\n\nAmes Aeronautical Laboratory,\nNational Advisory Committee for Aeronautics,\nMoffett Field, Calif.", "timestamp": "2026-07-22T04:41:21.413701+00:00"}
{"citation_id": "19930085838", "source_url": "https://ntrs.nasa.gov/api/citations/19930085838/downloads/19930085838.pdf", "page_number": 99, "total_pages": 118, "image_filename": "19930085838_p99.jpg", "text": "NACA RM No. L9B23\n97\n\n<!-- Image (153, 141, 832, 866) -->\n\n(e) $\\delta_F = 40^\\circ$.\nFigure 12.- Continued.", "timestamp": "2026-07-22T04:41:24.332002+00:00"}
{"citation_id": "19930085965", "source_url": "https://ntrs.nasa.gov/api/citations/19930085965/downloads/19930085965.pdf", "page_number": 53, "total_pages": 67, "image_filename": "19930085965_p53.jpg", "text": "52\n\n$$\n\\beta_2 - \\delta_2, \\text{deg}\n$$\n\n$$\nH_{\\max 2}/H_{\\max 1}\n$$\n\n[Figure: Graph showing variation of $\\beta_2 - \\delta_2$ with $H_{\\max 2}/H_{\\max 1}$, with curve rising from (1,0) to approximately (10,10), then leveling off near 10.2 up to 200. X-axis is logarithmic scale from 1 to 200; Y-axis linear from 0 to 12. NACA logo at bottom right of plot area.]\n\nFigure 9. - Variation of $\\beta_2 - \\delta_2$ with $H_{\\max 2}/H_{\\max 1}$.\n\nNACA RM E9E06", "timestamp": "2026-07-22T04:41:24.706692+00:00"}
{"citation_id": "19930082245", "source_url": "https://ntrs.nasa.gov/api/citations/19930082245/downloads/19930082245.pdf", "page_number": 19, "total_pages": 66, "image_filename": "19930082245_p19.jpg", "text": "[No readable text detected]", "timestamp": "2026-07-22T04:41:24.889738+00:00"}
{"citation_id": "19930082485", "source_url": "https://ntrs.nasa.gov/api/citations/19930082485/downloads/19930082485.pdf", "page_number": 13, "total_pages": 62, "image_filename": "19930082485_p13.jpg", "text": "12\nNACA TN No. 1810\n\nAPPENDIX A\n\nSTREAM-FILAMENT THEORY\n\nThe two-dimensional flow between curved surfaces may be studied by the stream-filament theory if the channel length is great compared to its width. This method consists in combining the conditions of irrotationality of flow with the principle of continuity of flow.\n\nDetermination of velocity variation across channel. - In the general case of the motion of a compressible, frictionless, perfect gas between curved surfaces (fig. 13), at any point in the channel the fluid rotates about an instantaneous center at radius $r$ with velocity $V$. Inasmuch as the fluid is considered irrotational,\n\n$$\n\\frac{dV}{dn} = - \\frac{V}{r} = - CV \\tag{1}\n$$\n\nThe derivative is negative, inasmuch as the positive direction is chosen as that from the suction surface to the pressure surface.\n\nThe curvature of the streamline is assumed to vary linearly from the suction surface to the pressure surface and is considered positive if the center of curvature is below the surface.\n\n$$\nC = C_1 + \\frac{C_2 - C_1}{n_o} n \\tag{2}\n$$\n\n$$\n= C_1 + \\frac{\\Delta C}{n_o} n \\tag{3}\n$$\n\nThen\n\n$$\ndC = \\frac{\\Delta C}{n_o} dn \\tag{4}\n$$\n\nIf equation (1) is rewritten in terms of curvature and equation (4) is used,\n\n$$\n\\frac{dV}{V} = - \\frac{n_o}{\\Delta C} C \\ dC \\tag{5}\n$$", "timestamp": "2026-07-22T04:41:26.053513+00:00"}
{"citation_id": "19930090382", "source_url": "https://ntrs.nasa.gov/api/citations/19930090382/downloads/19930090382.pdf", "page_number": 30, "total_pages": 37, "image_filename": "19930090382_p30.jpg", "text": "32\nNACA RM L9I07\n\nCONFIDENTIAL\n\nThrust coefficient, $C_T$\nPower coefficient, $C_P$\nTip Mach number, $M_t$\nEfficiency, $\\eta$\n\nAdvance ratio, J\n(k) M=0.85.\nFigure 5 - Continued.\n\nCONFIDENTIAL\n\nNACA", "timestamp": "2026-07-22T04:41:28.871142+00:00"}
{"citation_id": "19930086015", "source_url": "https://ntrs.nasa.gov/api/citations/19930086015/downloads/19930086015.pdf", "page_number": 48, "total_pages": 54, "image_filename": "19930086015_p48.jpg", "text": "```markdown\nNACA RM A9D24\n\nCONFIDENTIAL\n\n.60\n.50\n.40\n.30\n.20\n.10\n0\n-.10\n\nO vertical\n◇ upright\n□ inverted\n\nLift coefficient, $C_L$\n\n0 .01 .02 .03 .04 .05 .06 .07\nDrag coefficient, $C_D$\n\n0 2 4 6 8 10\nAngle of attack, $\\alpha$, deg\n\n0 -.04 -.08 -.12 -.16 -.20\nPitching-moment coefficient, $C_{m_{c/4}}$\n\n(c) D=88.52; M=1.73.\n\nFigure 13.- Concluded.\n\nCONFIDENTIAL\n\n47\n\n[Figure: NACA logo]\n```", "timestamp": "2026-07-22T04:41:34.161818+00:00"}
{"citation_id": "19930086081", "source_url": "https://ntrs.nasa.gov/api/citations/19930086081/downloads/19930086081.pdf", "page_number": 39, "total_pages": 44, "image_filename": "19930086081_p39.jpg", "text": "NACA RM L9H05\n37\n\nCONFIDENTIAL\n\n.2\n.1\n$C_{BM_f}$\n0\n-.1\n-4 -2 0 2 4 6 8\n$\\alpha$, deg\n$\\delta = 0.5^\\circ$\n\n.2\n.1\n$C_{BM_f}$\n0\n-.1\n-6 -4 -2 0 2 4\n$\\alpha$, deg\n$\\delta = 4.4^\\circ$\n\n.2\n.1\n$C_{BM_f}$\n0\n-6 -4 -2 0 2 4\n$\\alpha$, deg\n$\\delta = 8.6^\\circ$\n\n.2\n.1\n$C_{BM_f}$\n0\n-8 -6 -4 -2 0\n$\\alpha$, deg\n$\\delta = 12.8^\\circ$\n\nCONFIDENTIAL\n\n-4 -2 0 2 4\n$\\alpha$, deg\n$\\delta = 2.5^\\circ$\n\n-6 -4 -2 0 2\n$\\alpha$, deg\n$\\delta = 6.4^\\circ$\n\n-8 -6 -4 -2 0\n$\\alpha$, deg\n$\\delta = 10.4^\\circ$\n\nNACA\n\n(d) Bending moment plotted against $\\alpha$.\nFigure 16.- Concluded.", "timestamp": "2026-07-22T04:41:38.438267+00:00"}
{"citation_id": "19930085842", "source_url": "https://ntrs.nasa.gov/api/citations/19930085842/downloads/19930085842.pdf", "page_number": 87, "total_pages": 104, "image_filename": "19930085842_p87.jpg", "text": "```markdown\nNACA RM L9C29\n83\n\nPropeller advance ratio, $V/nD$\nLift coefficient, $C_L$\nTorque coefficient, $Q_c$\nResultant drag coefficient, $C_{DR}$\n\n[Figure: Graph plotting Propeller advance ratio, Lift coefficient, and Resultant drag coefficient against Torque coefficient. Data points are marked with squares. A legend indicates $\\beta, deg = 11.5$. The National Advisory Committee for Aeronautics logo is present in the bottom right corner of the graph.]\n\n(j) $\\alpha_1 = 54^\\circ$.\nFigure 43.- Continued.\n```", "timestamp": "2026-07-22T04:41:49.652074+00:00"}
{"citation_id": "19930082498", "source_url": "https://ntrs.nasa.gov/api/citations/19930082498/downloads/19930082498.pdf", "page_number": 5, "total_pages": 49, "image_filename": "19930082498_p5.jpg", "text": "4\nNACA TN No. 1838\n\nRESULTS AND DISCUSSION\n\nThe results of this investigation of a large number of muffler configurations are presented in tabular form. Table I gives the results for tests with the propeller attached to the engine and table II presents the results for tests with the propeller removed. The over-all sound-pressure level and the frequency analysis of the sound are given for the configurations presented. Most of the engine-exhaust sound components are found at frequencies which are integral multiples of one-half the fundamental firing frequency of the engine. However, in a few cases, frequencies were found which did not bear this relationship to the fundamental. For these cases, and also for those cases in which sounds are found at frequencies above the seventh harmonic of the firing frequency, extra columns have been provided in table II, headed \"Other sounds.\" The frequency and decibel level of two of these components are given in this column. Where more were found, the two loudest components are presented in the table. Back pressures are listed as low, medium, or high. At 2000 rpm back pressures below 0.8 psi are considered low, those from 0.8 psi to 1.2 psi are medium, and those above 1.2 psi are high. At 2790 rpm the medium-pressure range runs from 1.9 psi to 2.5 psi. In the few cases where back pressure is medium at one speed and high at another it is listed as medium. These back-pressure classifications have been arbitrarily chosen. The measurements indicated that the horsepower losses due to back pressure are small for the range of back pressure found in this investigation.\n\nTable II may be consulted for detailed information on a particular muffler. The following discussion is intended to cover only general results of this investigation and is based on satisfactory muffler performance at engine speeds between 1650 and 2790 rpm. Engine speeds below cruising will be encountered in practice only at low engine power in taxiing and for very short periods when opening the throttle for a take-off and throttling back for a glide; therefore, good attenuation characteristics may not be necessary below cruising speed. A muffler designed to operate only from cruising speed to maximum speed could probably be somewhat smaller than a muffler designed for the wide range of engine speed used in these tests.\n\nBase Conditions\n\nThe frequency analysis of the first configuration listed in table I, consisting of the original engine with the propeller operating at 2000 rpm, full throttle, shows an over-all sound-pressure level of 98 decibels. The loudest component of the propeller noise is found at the fundamental frequency of the propeller (66.5 cps) with a level of 92 decibels, and the loudest component of the engine noise is found at the fundamental firing frequency of the engine (100 cps) with a level of 97 decibels. The over-all sound-pressure level of the propeller alone", "timestamp": "2026-07-22T04:41:52.740399+00:00"}
{"citation_id": "19930086151", "source_url": "https://ntrs.nasa.gov/api/citations/19930086151/downloads/19930086151.pdf", "page_number": 33, "total_pages": 34, "image_filename": "19930086151_p33.jpg", "text": "NACA RM L9J28\n31\n\nCONFIDENTIAL\n\nWing-tip helix angle, $\\frac{pb}{2V}$, radians\n\n(a) Triangular wing-tip aileron on plain wing.\n(b) Parallelogram wing-tip aileron on plain wing.\n\n(d$\\delta_a$)\n0\n5\n10\n16\n\n(c) Triangular wing-tip aileron on wing with end plate.\n(d) Parallelogram wing-tip aileron on wing with end plate.\n\nTotal aileron deflection, $\\delta_{a_1}$, deg\nTotal aileron deflection, $\\delta_{a_1}$, deg\n\nCONFIDENTIAL\n\nFigure 15.— Variation of estimated wing-tip helix angle $\\frac{pb}{2V}$ with total aileron deflection for the 45° sweptback complete wing. Aileron differential, 2:1 (approximately).", "timestamp": "2026-07-22T04:41:52.842624+00:00"}
{"citation_id": "19930082487", "source_url": "https://ntrs.nasa.gov/api/citations/19930082487/downloads/19930082487.pdf", "page_number": 12, "total_pages": 33, "image_filename": "19930082487_p12.jpg", "text": "10\nNACA TN No. 1813\n\nREFERENCES\n\n1. Graham, Donald J., Nitzberg, Gerald E., and Olson, Robert N.:\nA Systematic Investigation of Pressure Distributions at High\nSpeeds Over Five Representative NACA Low-Drag and Conventional\nAirfoil Sections. NACA Rep. No. 832, 1945.\n\n2. Lindsey, W.F., Daley, Bernard N., and Humphreys, Milton D.:\nThe Flow and Force Characteristics of Supersonic Airfoils\nat High Subsonic Speeds. NACA TN No. 1211, 1947.\n\n3. Allen, H. Julian, Heaslet, Max. A., and Nitzberg, Gerald E.:\nThe Interaction of Boundary Layer and Compression Shock and\nits Effect Upon Airfoil Pressure Distributions. NACA RM No.\nA7A02, 1947.", "timestamp": "2026-07-22T04:41:55.029904+00:00"}
{"citation_id": "19930085965", "source_url": "https://ntrs.nasa.gov/api/citations/19930085965/downloads/19930085965.pdf", "page_number": 54, "total_pages": 67, "image_filename": "19930085965_p54.jpg", "text": "NACA RM E9E06\n\n- Air gap\n- Water jacket\n- Blade\n- Coil\n- Air gap\n- Iron laminations\n- Water out\n- Water in\n\nFigure 10. - Equipment utilized for determining eddy-current heat generated in blade.\n\nNACA\n\n53", "timestamp": "2026-07-22T04:41:56.375754+00:00"}
{"citation_id": "19930082245", "source_url": "https://ntrs.nasa.gov/api/citations/19930082245/downloads/19930082245.pdf", "page_number": 20, "total_pages": 66, "image_filename": "19930082245_p20.jpg", "text": "NACA TN No. 1596\n\n[Figure: Method of model installation in Langley 8-foot high-speed tunnel for present tests.]\n\nFigure 1.- Method of model installation in Langley 8-foot high-speed tunnel for present tests.\n\nNACA\nL-15951\n\n19", "timestamp": "2026-07-22T04:41:58.110552+00:00"}
{"citation_id": "19930082511", "source_url": "https://ntrs.nasa.gov/api/citations/19930082511/downloads/19930082511.pdf", "page_number": 8, "total_pages": 99, "image_filename": "19930082511_p8.jpg", "text": "6\nNACA TN No. 1826\n\nthe two-dimensional open tunnel (that is, a rectangular tunnel with closed sides but open top and bottom) show, however, very little difference between the tunnel-induced-downwash distributions for the tunnel with two exit lips and the tunnel with one exit lip. That is, if figure 3(a) is assumed to represent a two-dimensional flow, the fact that the upper lip of the exit is out of the flow field so that the lower lip takes over the entire burden of straightening the jet does not greatly affect the induced downwash.\n\nThe effect of the exit lip on the flow phenomena is the least clear of the various phases of the present problem. For open wind tunnels having essentially unflared exits, similar to that indicated in figure 3(a), the suggestions of the preceding paragraph are probably adequate. The exit of the Langley full-scale tunnel, however, has a large bell mouth, and when airplanes are being tested at high lift coefficients a downward deflection of the air off the lower part of the bell, roughly as indicated in figure 3(b), occurs. Whether the previously suggested concepts or, indeed, any linear theory can serve satisfactorily for this case seems questionable.\n\nUnequal surface pressures.- An interesting method of avoiding spillage suggests itself in the case of the two-dimensional open tunnel: If the space below the tunnel is inclosed, an excess pressure will be built up in this space, compared with the pressure in the space above the upper free surface, so that the flow will be pushed up sufficiently to eliminate the spillage and ensure precise contact of the lower free surface with the lower exit lip. (See fig. 3(c).) The extent to which a free two-dimensional jet can be deformed by a pressure difference across its boundaries, or, stated differently, the extent to which a two-dimensional free jet will deform in order to follow the only available path, is indicated by the smoke-flow photograph in figure 4. The setup consisted merely of a two-dimensional open jet with entrance and exit sections displaced vertically relative to each other, arranged between transparent side walls, and provided with enclosed spaces above and below.\n\nDetails of interest in the figure, in addition to the jet deformation, are:\n\n(1) Separation of the flow from the upper lip of the exit, because of the large angle of entry. A small bell mouth at the exit lip might have prevented such separation.\n\n(2) The rough flow on the upper surface at the entrance, compared with the smooth flow on the lower surface, reflects the fact that the boundary layer approaching the entrance is subjected to a rising pressure on the upper surface and a dropping pressure on the lower surface.\n\n(3) Because of turbulent mixing at the free surfaces, a certain amount of the air in the closed chambers above and below the jet is entrained in the jet. An equivalent quantity must be released, or skimmed off, at the exit in order that the total quantity in each chamber", "timestamp": "2026-07-22T04:41:59.187925+00:00"}
{"citation_id": "19930085838", "source_url": "https://ntrs.nasa.gov/api/citations/19930085838/downloads/19930085838.pdf", "page_number": 100, "total_pages": 118, "image_filename": "19930085838_p100.jpg", "text": "98\nNACA RM No. L9B23\n\n[Figure: A graph plotting \"Flap section hinge-moment coefficient, $c_{h_f}$\" on the y-axis against \"Section angle of attack, $\\alpha_c$, deg\" on the x-axis. The y-axis ranges from +0.20 to -0.40. The x-axis ranges from -20 to 20. The graph contains multiple curves with different markers. A legend indicates the curves correspond to $\\delta_f$ (deg) values of -10, -15, -20, and -24.8, with $\\delta_a = 0^\\circ$. The NACA logo is present in the bottom right corner of the plot area.]\n\n(f) $\\delta_f = 40^\\circ$.\nFigure 12.- Continued.", "timestamp": "2026-07-22T04:42:00.309392+00:00"}
{"citation_id": "19930082485", "source_url": "https://ntrs.nasa.gov/api/citations/19930082485/downloads/19930082485.pdf", "page_number": 14, "total_pages": 62, "image_filename": "19930082485_p14.jpg", "text": "NACA TN No. 1810\n13\n\nWhen equation (5) is integrated,\n\n$$\n\\log_e V = - \\frac{n_b C^2}{2 \\Delta C} + \\text{constant} \\tag{6}\n$$\n\nor\n\n$$\n\\frac{V}{V_m} = \\exp \\left[ - \\frac{n_b}{2 \\Delta C} (C^2 - C_m^2) \\right] \\tag{7}\n$$\n\nwhere $V$ and $V_m$ represent the velocity at any two points along the potential line.\n\nEvaluation of velocity from mass flow. - If the velocity at any point along a potential line is known, then the rest of the velocities along the line can be determined, as indicated in equation (7). From the use of the continuity equation, the velocity at one point may be determined.\n\nThe differential quantity of mass flow per unit depth of channel\n\n$$\ndW = \\rho_s V \\, dn \\tag{8}\n$$\n\nor in terms of density and temperature at stagnation\n\n$$\ndW = \\rho_t \\left( 1 - \\frac{V^2}{2 \\, c_p \\, T_t} \\right)^{\\frac{1}{\\gamma - 1}} V \\, dn \\tag{9}\n$$\n\nNow, let\n\n$$\nZ = \\frac{V^2}{2 \\, c_p \\, T_t} \\tag{10}\n$$\n\nthen,", "timestamp": "2026-07-22T04:42:02.037103+00:00"}
{"citation_id": "19930085930", "source_url": "https://ntrs.nasa.gov/api/citations/19930085930/downloads/19930085930.pdf", "page_number": 92, "total_pages": 92, "image_filename": "19930085930_p92.jpg", "text": "NACA-Langley - 5-12-49 - 300\n\nCONFIDENTIAL\n\nNACA RM L9907\n\n[Figure: A shadowgraph of the flow at an angle of attack of 40.00°.]\n\nFigure 43.— A shadowgraph of the flow at an angle of attack of 40.00°.\n\nCONFIDENTIAL\n\nNACA\n\n91", "timestamp": "2026-07-22T04:42:04.126622+00:00"}
{"citation_id": "19930082447", "source_url": "https://ntrs.nasa.gov/api/citations/19930082447/downloads/19930082447.pdf", "page_number": 15, "total_pages": 24, "image_filename": "19930082447_p15.jpg", "text": "NACA TN No. 1775\n\nDeck\nChine\n0 2 5 9 14 21 29 38 47 58 72 87.25 106.625 120.75\n19.4\"\n9.0\"\nChine\n0\n2\n5\n9\n14\n21\n29\n38\n47\n17.25\"\n40°\nDatum line\nPC\n120.75\"\n72\"\nNACA\nFigure 1.- Lines of Langley impact-basin float model M-3.\n13", "timestamp": "2026-07-22T04:42:05.560511+00:00"}
{"citation_id": "19930090382", "source_url": "https://ntrs.nasa.gov/api/citations/19930090382/downloads/19930090382.pdf", "page_number": 31, "total_pages": 37, "image_filename": "19930090382_p31.jpg", "text": "```markdown\nNACA RM L6I07\n33\n\nCONFIDENTIAL\n\n<!-- Image (66, 109, 868, 999) -->\n\nPower coefficient, $C_P$\nThrust coefficient, $C_T$\nAdvance ratio, J\nEfficiency, $\\eta$\nTip Mach number, $M_t$\n\nCONFIDENTIAL\n(k) M=0.85 Concluded\nFigure 5 - Continued.\n```", "timestamp": "2026-07-22T04:42:06.845792+00:00"}
{"citation_id": "19930086015", "source_url": "https://ntrs.nasa.gov/api/citations/19930086015/downloads/19930086015.pdf", "page_number": 49, "total_pages": 54, "image_filename": "19930086015_p49.jpg", "text": "48\nCONFIDENTIAL\nNACA RM A59E24\n\nTheory\nExperiment : $\\circ \\Delta \\alpha = 5.35^\\circ$ (Model Vertical)\n$\\Delta \\Delta \\alpha = 3.70^\\circ$ (Model Horizontal)\n$\\square \\Delta \\alpha = 5.74^\\circ$ (Model Horizontal)\n\nLoading coefficient\nper unit angle of attack, $R_\\alpha$, per deg\n.18\n.16\n.14\n.12\n.10\n.08\n.06\n.04\n.02\n0\n\nPercent of local chord\n0 20 40 60 80 100\n\n(a) M = 1.30.\nFigure 14.- Load distribution on a wing with the leading edge swept back 63°.\n\nCONFIDENTIAL", "timestamp": "2026-07-22T04:42:08.380180+00:00"}
{"citation_id": "19930092013", "source_url": "https://ntrs.nasa.gov/api/citations/19930092013/downloads/19930092013.pdf", "page_number": 15, "total_pages": 21, "image_filename": "19930092013_p15.jpg", "text": "APPARATUS FOR VARYING EFFECTIVE DIHEDRAL IN FLIGHT 11\n\nHigh-speed condition.—The indicated airspeed was 250 knots. Flaps and gear were up. It was necessary to fly the airplane in a slight dive at this speed in order to eliminate the necessity of using excessive engine power for long periods. Because of this time-consuming procedure, the testing in this condition was limited to a brief evaluation of the characteristics in steady sideslips and lateral oscillations and of pilots’ opinions for three pilots.\n\nAll flights were made at a pressure altitude of approximately 7,000 feet. Because of its experimental nature the apparatus was not used in flight close to the ground.\n\nRESULTS AND DISCUSSION\n\nMeasurement of the effective dihedral.—Figures 11 and 12 are presentations of the pertinent data obtained during steady, straight sideslips in the landing-approach and cruising conditions, respectively. Pilot-applied total aileron deflection and aileron stick force are shown as functions of sideslip angle. Since the test speeds during this investigation were lower than those employed in part I, the sideslip angles developed during rudder-fixed aileron rolls (and the associated adverse effect on $pb/2V$) were greater. Hence, the method of evaluating $C_{l_\\beta}$ and $\\Gamma_e$ from sideslip data used in part I was not used in evaluating the data of figures 11 and\n\n12. Instead, values of $C_{l_\\beta}$ for the two test conditions were taken from wind-tunnel tests of a $\\frac{1}{6}$-scale model of the test airplane, and these values, together with the variations of pilot-applied aileron deflection with sideslip shown in figures 11 and 12, made possible the computation of $C_{l_\\beta}$ for each servo setting. The same value of $C_{l_\\beta}/\\Gamma_e$ of $-0.000225$ per degree squared used in part I was used to compute the values of $\\Gamma_e$.\n\nIt is seen in figures 11 and 12 that in the landing-approach condition $\\Gamma_e$ was varied from $-18.2^\\circ$ to $28.4^\\circ$, and in the cruising condition from $-12.4^\\circ$ to $24.4^\\circ$. The corresponding values of $C_{l_\\beta}$ are noted in the figures. The wider range of $\\Gamma_e$ covered in the approach condition as compared with that covered in the cruising condition was caused by higher aileron effectiveness in the approach condition. Sufficient sideslip data (not presented here) were obtained in the high-speed condition to show that $\\Gamma_e$ did not change for a given setting of the apparatus when the airspeed was changed from 180 knots to 250 knots.\n\nOscillatory characteristics of the airplane.—Time histories of typical control-fixed oscillations in the landing-approach condition with the apparatus set for effective dihedrals of $28.4^\\circ$, $5.3^\\circ$ (normal airplane, apparatus inoperative), and $-3.1^\\circ$ are shown in figure 13. Figure 14 shows similar time\n\n[Figure: Graphs showing Rudder angle, Sideslip angle, and Rolling velocity over Time for three conditions labeled (a), (b), and (c)]\n\n(a) $\\Gamma_e$ $28.4^\\circ$.\n(b) $\\Gamma_e$ $5.3^\\circ$.\n(c) $\\Gamma_e$ $-3.1^\\circ$.\n\nFIGURE 13.—Time histories of typical control-fixed lateral oscillations. Landing-approach condition.", "timestamp": "2026-07-22T04:42:18.017882+00:00"}
{"citation_id": "19930085842", "source_url": "https://ntrs.nasa.gov/api/citations/19930085842/downloads/19930085842.pdf", "page_number": 88, "total_pages": 104, "image_filename": "19930085842_p88.jpg", "text": "84\nNACA RM L9029\n\nPropeller advance-diameter ratio, $V/nD$\nLift coefficient, $C_L$\nTorque coefficient, $Q_c$\nResultant drag coefficient, $C_{DR}$\n\n$\\beta, deg$\n10\n11.5\n\nNATIONAL ADVISORY\nCOMMITTEE FOR AERONAUTICS\n\n(k) $\\alpha_u = 60^\\circ$.\nFigure 43.- Continued.", "timestamp": "2026-07-22T04:42:18.948643+00:00"}
{"citation_id": "19930086081", "source_url": "https://ntrs.nasa.gov/api/citations/19930086081/downloads/19930086081.pdf", "page_number": 40, "total_pages": 44, "image_filename": "19930086081_p40.jpg", "text": "38\nNACA RM L9H05\n\nCONFIDENTIAL\n\n$$\n\\begin{array}{c|c}\n\\delta & \\\\\n(\\text{deg}) & \\\\\n\\hline\n\\circ & 0 \\\\\n\\square & 2.4 \\\\\n\\Diamond & 4.1 \\\\\n\\triangle & 5.8 \\\\\n\\nabla & 8.2 \\\\\n\\triangleright & 9.7 \\\\\n\\triangleleft & 12.0\n\\end{array}\n$$\n\n$$\n\\begin{array}{c}\n.4 \\\\\n.3 \\\\\n.2 \\\\\n.1 \\\\\nC_{Nf} \\\\\n0 \\\\\n-.1 \\\\\n-.2\n\\end{array}\n$$\n\n[Figure: Graph plotting $C_{Nf}$ against $\\alpha, \\text{deg}$ with multiple data series represented by different symbols corresponding to $\\delta$ values. A NACA logo is present in the bottom right corner of the plot area.]\n\n$$\n\\begin{array}{cccccccccc}\n-8 & -6 & -4 & -2 & 0 & 2 & 4 & 6 & 8 \\\\\n& & & & \\alpha, \\text{deg} & & & &\n\\end{array}\n$$\n\nCONFIDENTIAL\n\n(a) Normal force plotted against $\\alpha$.\n\nFigure 17.- Aerodynamic loading characteristics of a 0.07t/c half-delta control surface. Fence off. Data presented with respect to control surface axes. Second series of tests.", "timestamp": "2026-07-22T04:42:21.457094+00:00"}
{"citation_id": "19930086078", "source_url": "https://ntrs.nasa.gov/api/citations/19930086078/downloads/19930086078.pdf", "page_number": 41, "total_pages": 42, "image_filename": "19930086078_p41.jpg", "text": "NACA RM L59D04\n\nCONFIDENTIAL\n\n| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |", "timestamp": "2026-07-22T04:42:21.763932+00:00"}
{"citation_id": "19930082496", "source_url": "https://ntrs.nasa.gov/api/citations/19930082496/downloads/19930082496.pdf", "page_number": 6, "total_pages": 50, "image_filename": "19930082496_p6.jpg", "text": "NACA TN No. 1836\n\nrods and the grips were then installed on the tensile machine and a tensile specimen was placed in the grips and the furnace positioned about the specimen. A load of 3000 pounds per square inch was applied to the specimen and alinement was secured by tapping gently on the rod and grips until misalignment, indicated by wire strain gages mounted on the specimen (fig. 2), was below 20 percent, which was considered satisfactory. The load was then reduced to 1000 pounds per square inch.\n\nThe furnace temperature was raised to $100^\\circ$ F above the evaluation temperature and the specimen was allowed to soak in helium atmosphere for approximately $12\\frac{1}{2}$ hours while being subjected to the load of 1000 pounds per square inch in order to improve alinement and to relieve local stresses. This period of soaking was subsequently changed to 4 hours. During soaking, the nominal load of $1000 \\pm 100$ pounds per square inch was maintained by the hydraulic loading system of the tensile machine. Upon completion of the soaking period, the temperature was lowered to the evaluation temperature within approximately 1/2 hour and the load increased at the rate of 2000 pounds per square inch per minute until the specimen fractured. The loading rate conformed to recommendations of reference 7. Specimen temperature was maintained within $\\pm 10^\\circ$ F.\n\nThermal-Shock Evaluation\n\nApparatus for the thermal-shock evaluation consisted of an electric furnace employing nonmetallic resistor bars to heat the specimen and an air-quenching system to cool the specimen. The specimens investigated were 1/4-inch-thick disks, 2 inches in diameter. Figure 3 shows the thermal-shock evaluation unit, which was so arranged that the specimen after heating could be moved directly into a stream of quenching air. Holders made of high-temperature alloys (fig. 4) were used to support and to transport the specimens from the furnace to the air-quenching stream. A glass window in the air-quenching chamber allowed observation of the specimen during the cooling portion of the test cycle.\n\nTemperature of the furnace was measured by a thermocouple connected to a potentiometer and controlled by a second thermocouple connected to an electric temperature-control system. Chromel-alumel thermocouples were used up to $2200^\\circ$ F. Platinum - platinum-13-percent-rhodium thermocouples were used above $2200^\\circ$ F.\n\nThe specimens were inspected for internal and external flaws by radiographic and fluorescent-oil methods, respectively. Radiographic inspection revealed fine chemical segregation, which was not considered serious.", "timestamp": "2026-07-22T04:42:22.762098+00:00"}
{"citation_id": "19930082450", "source_url": "https://ntrs.nasa.gov/api/citations/19930082450/downloads/19930082450.pdf", "page_number": 13, "total_pages": 37, "image_filename": "19930082450_p13.jpg", "text": "12\nNACA TN No. 1778\n\nTABLE 3.- Z-PANEL PROPERTIES\n$$ \\left[ \\frac{t_w}{t_s} = 0.63; \\frac{b_w}{t_w} = 10.9; \\frac{b_s}{t_w} = 0.4; \\frac{F_{cy}}{E} = 31; \\frac{F_{cw}}{E} = k_1; \\frac{d}{t_w} = 1.84; \\frac{F_{cs}}{E} = 12.3 \\right] $$\n\n| $b_w/t_w$ | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 |\n| :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- |\n| 25 | 1.263 | 1.295 | 1.608 | 1.650 | 1.632 | 1.678 | 1.696 | 1.719 | 1.741 | 1.763 | 1.785 | 1.808 | 1.830 |\n| 26 | 1.251 | 1.281 | 1.591 | 1.637 | 1.614 | 1.670 | 1.681 | 1.712 | 1.732 | 1.755 | 1.777 | 1.799 | 1.821 |\n| 27 | 1.241 | 1.262 | 1.563 | 1.593 | 1.604 | 1.628 | 1.645 | 1.669 | 1.666 | 1.707 | 1.727 | 1.749 | 1.768 |\n| 28 | 1.203 | 1.223 | 1.512 | 1.562 | 1.571 | 1.602 | 1.622 | 1.642 | 1.662 | 1.681 | 1.701 | 1.721 | 1.741 |\n| 29 | 1.209 | 1.229 | 1.488 | 1.538 | 1.562 | 1.580 | 1.600 | 1.620 | 1.640 | 1.658 | 1.677 | 1.696 | 1.714 |\n| 30 | 1.169 | 1.188 | 1.506 | 1.523 | 1.543 | 1.562 | 1.580 | 1.595 | 1.617 | 1.636 | 1.654 | 1.673 | 1.692 |\n| 31 | 1.151 | 1.170 | 1.488 | 1.502 | 1.522 | 1.542 | 1.560 | 1.580 | 1.598 | 1.617 | 1.635 | 1.651 | 1.671 |\n| 32 | 1.140 | 1.157 | 1.475 | 1.492 | 1.509 | 1.527 | 1.541 | 1.561 | 1.579 | 1.595 | 1.614 | 1.631 | 1.648 |\n| 33 | 1.127 | 1.144 | 1.461 | 1.476 | 1.493 | 1.511 | 1.528 | 1.548 | 1.568 | 1.588 | 1.606 | 1.624 | 1.642 |\n| 34 | 1.114 | 1.130 | 1.447 | 1.463 | 1.479 | 1.496 | 1.512 | 1.528 | 1.545 | 1.564 | 1.577 | 1.594 | 1.610 |\n| 35 | 1.102 | 1.117 | 1.434 | 1.449 | 1.465 | 1.482 | 1.497 | 1.513 | 1.530 | 1.547 | 1.564 | 1.581 | 1.597 |\n| 36 | 1.291 | 1.406 | 1.422 | 1.437 | 1.453 | 1.468 | 1.484 | 1.499 | 1.515 | 1.530 | 1.545 | 1.561 | 1.576 |\n| 37 | 1.280 | 1.395 | 1.411 | 1.426 | 1.441 | 1.456 | 1.471 | 1.486 | 1.502 | 1.517 | 1.532 | 1.548 | 1.563 |\n| 38 | 1.270 | 1.385 | 1.400 | 1.414 | 1.429 | 1.444 | 1.458 | 1.473 | 1.487 | 1.502 | 1.517 | 1.532 | 1.546 |\n| 39 | 1.260 | 1.375 | 1.390 | 1.404 | 1.418 | 1.432 | 1.446 | 1.461 | 1.475 | 1.489 | 1.504 | 1.518 | 1.532 |\n| 40 | 1.252 | 1.367 | 1.380 | 1.394 | 1.408 | 1.422 | 1.436 | 1.450 | 1.464 | 1.477 | 1.491 | 1.505 | 1.519 |\n| 41 | 1.243 | 1.358 | 1.371 | 1.385 | 1.398 | 1.412 | 1.426 | 1.439 | 1.453 | 1.466 | 1.480 | 1.493 | 1.507 |\n| 42 | 1.235 | 1.349 | 1.362 | 1.375 | 1.388 | 1.401 | 1.415 | 1.428 | 1.441 | 1.454 | 1.467 | 1.481 | 1.494 |\n| 43 | 1.220 | 1.333 | 1.346 | 1.359 | 1.370 | 1.383 | 1.396 | 1.408 | 1.421 | 1.434 | 1.446 | 1.459 | 1.471 |\n| 44 | 1.206 | 1.318 | 1.330 | 1.342 | 1.354 | 1.366 | 1.378 | 1.391 | 1.403 | 1.415 | 1.427 | 1.439 | 1.451 |\n| 45 | 1.203 | 1.305 | 1.316 | 1.328 | 1.340 | 1.351 | 1.363 | 1.374 | 1.386 | 1.397 | 1.409 | 1.420 | 1.432 |\n| 46 | 1.202 | 1.293 | 1.304 | 1.315 | 1.326 | 1.337 | 1.348 | 1.359 | 1.370 | 1.382 | 1.393 | 1.404 | 1.415 |\n| 47 | 1.201 | 1.281 | 1.292 | 1.303 | 1.313 | 1.324 | 1.335 | 1.346 | 1.356 | 1.367 | 1.377 | 1.388 | 1.399 |\n| 48 | 1.261 | 1.271 | 1.281 | 1.292 | 1.302 | 1.312 | 1.322 | 1.333 | 1.343 | 1.353 | 1.364 | 1.374 | 1.384 |\n| 49 | 1.251 | 1.261 | 1.271 | 1.281 | 1.291 | 1.301 | 1.311 | 1.321 | 1.331 | 1.341 | 1.351 | 1.361 | 1.370 |\n| 50 | 1.242 | 1.252 | 1.262 | 1.271 | 1.281 | 1.291 | 1.300 | 1.310 | 1.319 | 1.329 | 1.339 | 1.349 | 1.358 |\n| 55 | 1.235 | 1.244 | 1.253 | 1.262 | 1.272 | 1.281 | 1.290 | 1.299 | 1.308 | 1.318 | 1.327 | 1.337 | 1.346 |\n| 60 | 1.227 | 1.236 | 1.245 | 1.254 | 1.263 | 1.272 | 1.280 | 1.289 | 1.298 | 1.306 | 1.315 | 1.324 | 1.332 |\n| 65 | 1.221 | 1.229 | 1.237 | 1.245 | 1.253 | 1.261 | 1.269 | 1.277 | 1.285 | 1.293 | 1.301 | 1.309 | 1.317 |\n| 70 | 1.201 | 1.209 | 1.217 | 1.225 | 1.233 | 1.241 | 1.249 | 1.257 | 1.265 | 1.273 | 1.280 | 1.288 | 1.296 |\n| 75 | 1.188 | 1.195 | 1.203 | 1.211 | 1.219 | 1.227 | 1.235 | 1.242 | 1.250 | 1.258 | 1.265 | 1.273 | 1.280 |\n\n| $b_w/t_w$ | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 |\n| :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- |\n| 25 | 2.048 | 2.047 | 2.246 | 2.457 | 2.673 | 2.894 | 3.120 | 3.348 | 3.583 | 3.822 | 4.066 | 4.311 | 4.562 |\n| 26 | 2.785 | 2.979 | 3.130 | 3.305 | 3.507 | 3.815 | 4.094 | 4.261 | 4.492 | 4.725 | 4.965 | 5.206 | 5.454 |\n| 27 | 2.729 | 2.920 | 3.116 | 3.319 | 3.527 | 3.739 | 3.955 | 4.176 | 4.400 | 4.625 | 4.854 | 5.087 | 5.324 |\n| 28 | 2.675 | 2.862 | 3.057 | 3.255 | 3.458 | 3.662 | 3.870 | 4.077 | 4.287 | 4.501 | 4.718 | 4.938 | 5.161 |\n| 29 | 2.626 | 2.809 | 2.998 | 3.192 | 3.387 | 3.588 | 3.787 | 3.990 | 4.196 | 4.406 | 4.620 | 4.837 | 5.056 |\n| 30 | 2.577 | 2.757 | 2.944 | 3.133 | 3.321 | 3.511 | 3.705 | 3.907 | 4.113 | 4.321 | 4.535 | 4.751 | 4.970 |\n| 31 | 2.531 | 2.705 | 2.890 | 3.077 | 3.270 | 3.467 | 3.662 | 3.876 | 4.087 | 4.305 | 4.525 | 4.745 | 4.976 |\n| 32 | 2.487 | 2.660 | 2.846 | 3.028 | 3.214 | 3.406 | 3.606 | 3.81", "timestamp": "2026-07-22T04:42:25.665473+00:00"}
{"citation_id": "19930082487", "source_url": "https://ntrs.nasa.gov/api/citations/19930082487/downloads/19930082487.pdf", "page_number": 13, "total_pages": 33, "image_filename": "19930082487_p13.jpg", "text": "NACA TN No. 1813\n11\n\n.7\n.6\n.5\n.4\n.3\n.2\n.1\n0\n\n.14\n.12\n.10\n.08\n.06\n.04\n.02\n0\n\nVariation of $c_l$ assuming lower-surface lift contribution constant above $M_o=0.65$.\n\n$c_l$\n$M_s$\n$c_d$\n$M_{cr}$\n$M_d$\n\nSection lift coefficient, $c_l$\nSection drag coefficient, $c_d$\n\n.3 .4 .5 .6 .7 .8 .9 0\nFree-stream Mach number, $M_o$\n\nNACA\n\nFigure 1.- Section lift and drag coefficients as functions of free-stream Mach number for NACA 23015 airfoil section at $2^\\circ$ angle of attack.", "timestamp": "2026-07-22T04:42:27.627909+00:00"}
{"citation_id": "19930082245", "source_url": "https://ntrs.nasa.gov/api/citations/19930082245/downloads/19930082245.pdf", "page_number": 21, "total_pages": 66, "image_filename": "19930082245_p21.jpg", "text": "[No readable text detected]", "timestamp": "2026-07-22T04:42:28.897055+00:00"}
{"citation_id": "19930085965", "source_url": "https://ntrs.nasa.gov/api/citations/19930085965/downloads/19930085965.pdf", "page_number": 55, "total_pages": 67, "image_filename": "19930085965_p55.jpg", "text": "54\n\n[Figure: Circuit schematic diagram]\n\n6100 cps\n\n0.01 - .03 mfd\n\nA\na.c.\n\n0.55 h\n\n24\nvolts\n\nA\nd.c.\n\n27 ohm\n\nA\na.c.\n\n20 mfd\n\nV\na.c.\n\nBlade\n\n[Figure: Graph of Coil current vs. Time]\n\nCoil\ncurrent\n\n0\n\nTime\n\nd.c.\n\nSine\nwave\na.c.\n\n$2\\sqrt{2}$ x rms value of a.-c. component\n\nTotal current\n\nNACA\n\nFigure 11. - Circuit schematic diagram for alternating-current\nplus direct-current experiment.\n\nNACA RM E9E06", "timestamp": "2026-07-22T04:42:29.073183+00:00"}
{"citation_id": "19930082476", "source_url": "https://ntrs.nasa.gov/api/citations/19930082476/downloads/19930082476.pdf", "page_number": 15, "total_pages": 41, "image_filename": "19930082476_p15.jpg", "text": "NACA TN No. 1801\n13\n\nTABLE I.- DIMENSIONAL CHARACTERISTICS OF TWIN-TAIL\nLOW-WING PERSONAL-OWNER-TYPE AIRPLANE\n\nOver-all length, ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .", "timestamp": "2026-07-22T04:42:29.281631+00:00"}
{"citation_id": "19930085838", "source_url": "https://ntrs.nasa.gov/api/citations/19930085838/downloads/19930085838.pdf", "page_number": 101, "total_pages": 118, "image_filename": "19930085838_p101.jpg", "text": "NACA RM No. L9B23\n99\n\n<!-- Image (136, 160, 898, 924) -->\n\nFigure 12.- Continued.", "timestamp": "2026-07-22T04:42:33.907052+00:00"}
{"citation_id": "19930082447", "source_url": "https://ntrs.nasa.gov/api/citations/19930082447/downloads/19930082447.pdf", "page_number": 16, "total_pages": 24, "image_filename": "19930082447_p16.jpg", "text": "[No readable text detected]", "timestamp": "2026-07-22T04:42:35.084414+00:00"}
{"citation_id": "19930082485", "source_url": "https://ntrs.nasa.gov/api/citations/19930082485/downloads/19930082485.pdf", "page_number": 15, "total_pages": 62, "image_filename": "19930082485_p15.jpg", "text": "14\nNACA TN No. 1810\n\n$$\n\\frac{dW}{\\rho_t \\sqrt{2} c_p T_t n_o} = (1 - Z)^{\\frac{1}{\\gamma-1}} \\sqrt{Z} \\frac{dn}{n_o} \\quad (11)\n$$\n\n$$\n(1 - Z)^{\\frac{1}{\\gamma-1}} = (1 - Z_m - Z + Z_m)^{\\frac{1}{\\gamma-1}}\n$$\n\n$$\n= (1 - Z_m)^{\\frac{1}{\\gamma-1}} \\left( 1 - \\frac{Z - Z_m}{1 - Z_m} \\right)^{\\frac{1}{\\gamma-1}} \\quad (12)\n$$\n\nwhere\n\n$$\nZ_m = \\frac{V_m^2}{2 c_p T_t} \\quad (13)\n$$\n\nThe second term in equation (12) may be expanded by the binomial theorem, choosing $\\sqrt{Z_m}$ at the point of average streamline curvature (channel center) so that $Z - Z_m$ will be small, and neglecting all but the first two terms of the expansion, then\n\n$$\n(1 - Z)^{\\frac{1}{\\gamma-1}} = (1 - Z_m)^{\\frac{1}{\\gamma-1}} \\left[ 1 + \\frac{1}{\\gamma-1} \\left( \\frac{Z_m}{1 - Z_m} \\right) - \\frac{1}{\\gamma-1} \\left( \\frac{Z}{1 - Z_m} \\right) \\right]\n$$\n\n$$\n= (1 - Z_m)^{\\frac{2-\\gamma}{\\gamma-1}} \\left[ 1 + Z_m \\left( \\frac{2-\\gamma}{\\gamma-1} \\right) - \\frac{Z}{\\gamma-1} \\right] \\quad (14)\n$$\n\nLet\n\n$$\nf = \\sqrt{Z_m} (1 - Z_m)^{\\frac{2-\\gamma}{\\gamma-1}} \\left[ 1 + Z_m \\left( \\frac{2-\\gamma}{\\gamma-1} \\right) \\right] \\quad (15)\n$$\n\nand", "timestamp": "2026-07-22T04:42:40.709529+00:00"}
{"citation_id": "19930082498", "source_url": "https://ntrs.nasa.gov/api/citations/19930082498/downloads/19930082498.pdf", "page_number": 6, "total_pages": 49, "image_filename": "19930082498_p6.jpg", "text": "NACA TN No. 1838\n\nmust be at least 92 decibels; therefore, the maximum possible sound reduction by muffling alone is evidently no more than 6 decibels (from 98 db to 92 db) at this engine speed. At take-off speed (2550 rpm) the over-all sound-pressure level of the conventional airplane at 300 feet is 87.5 decibels (reference 2). When corrected to 50 feet, the distance at which the ground measurements were made, this sound level increases to 102.5 decibels. (Corrected flight data are used here because the top speed of the engine and propeller combination in the ground test stand is below 2550 rpm.) At the same engine speed the sound-pressure level of the conventional engine installation with the propeller removed, however, is 97.5 decibels (reference 1). Consequently, at some engine speed between 2000 and 2550 rpm the propeller and engine noises must be of equal intensity. For airplanes of this type, therefore, both propeller and engine noise must be reduced to achieve a significant reduction in over-all noise. In addition, because most of the exhaust sound energy is concentrated at low frequencies, sound-reduction methods applicable only to high-frequency sound are of little value in reducing the over-all sound-pressure level.\n\nSeveral modifications not involving mufflers were made to the original exhaust system. When the two exhaust pipes were joined by a wye and exhausted through a common pipe (configuration 4, table II), a noticeable noise reduction was observed at the lower speeds. The data for this configuration with power off (engine switch off and throttle closed, engine being driven by the electric motor) give an indication of the lowest sound-pressure levels which can be obtained by exhaust muffling without also taking steps to silence the other engine noises. The wye is shown in use, with a typical muffler attached, in figure 6. The addition of a $90^\\circ$ elbow pointed upward (configuration 6, table II) resulted in a quite sizable noise reduction at all engine speeds. This simple upturned elbow proved more effective in reducing the over-all noise level than many of the small mufflers. The reason for this result is not clear, however, because theoretical considerations indicate that sound waves in this frequency range would have no strong directional properties after issuing from a $2\\frac{3}{4}$-inch unflanged pipe. This fact is verified by radial surveys made in the plane of a straight horizontal exhaust pipe (fig. 7) which show that the variation of sound-pressure level with angular position is not large enough to account for the sound-level reduction obtained with this upturned elbow. The back pressure due to the bend and the sound reflections from the bend may possibly account for the observed sound reduction.\n\nCommercial Mufflers\n\nThe mufflers discussed in this section were not designed for the particular engine which was used in this investigation. The airplane mufflers were, however, designed for other six-cylinder engines in the same general horsepower and speed range as the test engine; therefore, the results should be at least indicative of the performance to be", "timestamp": "2026-07-22T04:42:41.630330+00:00"}
{"citation_id": "19930082542", "source_url": "https://ntrs.nasa.gov/api/citations/19930082542/downloads/19930082542.pdf", "page_number": 1, "total_pages": 53, "image_filename": "19930082542_p1.jpg", "text": "```markdown\nFILE COPY\nNO. 2-W\n\nCASE FILE\nCOPY\n\nNACA TN No. 1867\n\nNATIONAL ADVISORY COMMITTEE\nFOR AERONAUTICS\n\nTECHNICAL NOTE\nNo. 1867\n\nA STUDY OF EFFECTS OF HEAT TREATMENT AND HOT-COLD-WORK\nON PROPERTIES OF LOW-CARBON N-155 ALLOY\n\nBy J. W. Freeman, E. E. Reynolds, D. N. Frey, and A. E. White\n\nUniversity of Michigan\n\n[Figure: NACA logo]\n\nWashington\nMay 1949\n\nFILE COPY\nTo be returned to\nthe files of the National\nAdvisory Committee\nfor Aeronautics\nWashington, D. C.\n\nN 62 53867\n```", "timestamp": "2026-07-22T04:42:46.037703+00:00"}
{"citation_id": "19930082511", "source_url": "https://ntrs.nasa.gov/api/citations/19930082511/downloads/19930082511.pdf", "page_number": 9, "total_pages": 99, "image_filename": "19930082511_p9.jpg", "text": "NACA TN No. 1826\n\nremain constant. This circulating mechanism results in the apparent overflow at the two exit lips. The return of the skimmed-off part to the jet surface can be seen at the bottom of the photograph.\n\nTunnel without a closed exit.- Some mention is made in the subsequent discussion of the hypothetical open tunnel having a closed upstream entrance region but no closed exit region, the open section thus extending downstream to infinity. Calculations for such an arrangement (see part II) are generally simpler than for the actual tunnel with the closed exit, and give very nearly the same answer, provided that the region of interest is much closer to the entrance than to the exit, as is usually the case. For this arrangement, solutions with an arbitrary contraction or expansion of the jet cannot exist, so that no effort need be made to avoid them. The solution for the general unsymmetrical case, however, will show the jet velocity downstream at infinity to be different from the velocity upstream in the closed part. The possibility that, in the two-dimensional case, different pressures might be assumed on the two free surfaces still exists for this type of tunnel, but the resulting jet will have a constant curvature after leaving the neighborhood of the body.\n\nAn upstream condition for the \"infinitely long\" open tunnel and a correction to the results of reference 8.- In many discussions of the two-dimensional open tunnel, the set of images indicated in figure 5(a) is used to satisfy the boundary condition that $u = 0$, and the resulting flow shows an upflow in front and an equal downflow in back, with no induced downwash at the wing itself. Actually, however, if the jet issues from a horizontal closed entrance - no matter how far upstream - it will remain essentially horizontal (because it is not subjected to any vertical force) until it reaches the wing. (See fig. 5(b).) In order to eliminate the undesired upstream upwash, a uniform downwash should therefore be added to the solution indicated in figure 5(a). (compare reference 7, p. 304.) Addition of this downwash does not affect the boundary conditions, since $u$ is still zero at the boundary. This case is discussed quantitatively in part II, where it is shown that the entrance-lip condition automatically provides the correct answer.\n\nAmong the rectangular wind tunnels for which corrections were given in reference 8 is a type with closed sides but open top and bottom. The calculated corrections for approximately square cross sections are approximately equal to those for the completely closed tunnel, a surprising result in view of the absence of any top or bottom constraint. The result is actually in error, as was discovered in an experimental effort to verify it (reference 9). In seeking to explain the errors the author of reference 9 pointed out that the image system used in reference 8 should have included an infinite row of vortices at infinity, and he showed how, by taking into account this row of vortices, the correct answer could be obtained. It could not be shown, however, that the extent of this row of vortices is of a higher order of infinity than is their distance from the origin, as is necessary if their effect is to be considered. The method of the preceding paragraph thus appears to be much simpler and more rigorous in such cases than is a discussion of the image vortices at infinity. One simply observes that the image system", "timestamp": "2026-07-22T04:42:48.207215+00:00"}
{"citation_id": "19930086081", "source_url": "https://ntrs.nasa.gov/api/citations/19930086081/downloads/19930086081.pdf", "page_number": 41, "total_pages": 44, "image_filename": "19930086081_p41.jpg", "text": "NACA RM L9H05\n39\n\nCONFIDENTIAL\n\n$C_{cf}$\n.04\n0\n0 2 4 6 8\n$\\alpha$, deg\n$\\delta = 0^\\circ$\n\n$C_{cf}$\n.04\n0\n-2 0 2 4 6\n$\\alpha$, deg\n$\\delta = 2.4^\\circ$\n\n$C_{cf}$\n.04\n0\n-4 -2 0 2 4\n$\\alpha$, deg\n$\\delta = 4.1^\\circ$\n\n$C_{cf}$\n.04\n0\n-4 -2 0 2 4\n$\\alpha$, deg\n$\\delta = 5.8^\\circ$\n\n$C_{cf}$\n.04\n0\n-6 -4 -2 0 2\n$\\alpha$, deg\n$\\delta = 8.2^\\circ$\n\n$C_{cf}$\n.04\n0\n-6 -4 -2 0 2\n$\\alpha$, deg\n$\\delta = 9.7^\\circ$\n\n$C_{cf}$\n.04\n0\n-8 -6 -4 -2 0\n$\\alpha$, deg\n$\\delta = 12.0^\\circ$\n\nCONFIDENTIAL\n\n(b) Chord force plotted against $\\alpha$.\n\nFigure 17.- Continued.\n\n[Figure: NACA logo]", "timestamp": "2026-07-22T04:42:49.559576+00:00"}
{"citation_id": "19930085842", "source_url": "https://ntrs.nasa.gov/api/citations/19930085842/downloads/19930085842.pdf", "page_number": 89, "total_pages": 104, "image_filename": "19930085842_p89.jpg", "text": "NACA RM L9C29\n85\n\nPropeller advance-\ndiameter ratio, V/nD\n\nLift coefficient, $C_L$\n\nTorque coefficient, $Q_c$\n\n$V/nD$\n\n$C_{DR}$\n\nResultant drag coefficient, $C_{DR}$\n\n$\\beta, deg$\n$= 11.3$\n\nNATIONAL ADVISORY\nCOMMITTEE FOR AERONAUTICS\n\n(2) $\\alpha_{11} = 72^\\circ$.\n\nFigure 43.- Continued.", "timestamp": "2026-07-22T04:42:55.386369+00:00"}
{"citation_id": "19930082487", "source_url": "https://ntrs.nasa.gov/api/citations/19930082487/downloads/19930082487.pdf", "page_number": 14, "total_pages": 33, "image_filename": "19930082487_p14.jpg", "text": "[No readable text detected]", "timestamp": "2026-07-22T04:42:55.998817+00:00"}
{"citation_id": "19930086151", "source_url": "https://ntrs.nasa.gov/api/citations/19930086151/downloads/19930086151.pdf", "page_number": 34, "total_pages": 34, "image_filename": "19930086151_p34.jpg", "text": "32\nNACA RM L9J28\n\nCONFIDENTIAL\n\nWing-tip helix angle, $\\frac{pb}{2V}$, radians\n\n(a) Triangular wing-tip aileron on plain wing.\n\n(b) Parallelogram wing-tip aileron on plain wing.\n\n$\\alpha$ (deg)\n0\n5\n10\n16\n\n(c) Triangular wing-tip aileron on wing with end plate.\n\n(d) Parallelogram wing-tip aileron on wing with end plate.\n\nTotal aileron deflection, $\\delta_a$, deg\n\nTotal aileron deflection, $\\delta_a$, deg\n\nCONFIDENTIAL\n\nFigure 16.— Variation of estimated wing-tip helix angle $\\frac{pb}{2V}$ with total aileron deflection for the 45° sweptback complete wing. Aileron differential, 3:1 (approximately).\n\nNACA-Langley - 12-14-49 - 225", "timestamp": "2026-07-22T04:42:57.900786+00:00"}
{"citation_id": "19930086078", "source_url": "https://ntrs.nasa.gov/api/citations/19930086078/downloads/19930086078.pdf", "page_number": 42, "total_pages": 42, "image_filename": "19930086078_p42.jpg", "text": "NACA-Langley - 5-20-49 - 373\n\nCONFIDENTIAL\n\n| $S_g/S$ | Nominal extension |\n| :--- | :--- |\n| .0011 | $\\frac{1}{4}$ |\n| .020 | $\\frac{1}{2}$ |\n| .028 | $\\frac{3}{4}$ |\n| .040 | Full |\n\n| $S_g/S$ | Nominal extension |\n| :--- | :--- |\n| .0010 | $\\frac{1}{4}$ |\n| .020 | $\\frac{1}{2}$ |\n| .030 | $\\frac{3}{4}$ |\n| .040 | Full |\n\n| $S_g/S$ | Nominal extension |\n| :--- | :--- |\n| .0005 | $\\frac{1}{4}$ |\n| .011 | $\\frac{1}{2}$ |\n| .016 | $\\frac{3}{4}$ |\n| .021 | Full |\n\nWing-tip helix angle, $\\frac{pb}{2V}$, radians\nRight roll\nLeft roll\n\nLift coefficient, $C_L$\nLift coefficient, $C_L$\nLift coefficient, $C_L$\n\nCONFIDENTIAL\n\nNACA\n\n(a) Large-chord aileron.\n(b) Triangular aileron.\n(c) Small-chord aileron.\n\nFigure 19.- Variation of wing-tip helix angle with lift coefficient for the 45° sweptback wing with extensible wing-tip ailerons. $\\delta_a = 4^\\circ$.\n\nNACA RM L9H04\n40", "timestamp": "2026-07-22T04:42:58.420148+00:00"}
{"citation_id": "19930093773", "source_url": "https://ntrs.nasa.gov/api/citations/19930093773/downloads/19930093773.pdf", "page_number": 18, "total_pages": 47, "image_filename": "19930093773_p18.jpg", "text": "```markdown\n| 40 | 25,000 | 1.211 | 0.530 | 778 | 434 | 6459 | 456 | 1973 | 1269 | 41.79 | 1590 | 1.233 | 0.0106 | 1200 | 1469 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  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{"citation_id": "19930082245", "source_url": "https://ntrs.nasa.gov/api/citations/19930082245/downloads/19930082245.pdf", "page_number": 22, "total_pages": 66, "image_filename": "19930082245_p22.jpg", "text": "NACA TN No. 1596\n21\n\n<!-- Image (109, 136, 918, 377) -->\n\n(a) Wing section with true-contour aileron.\n\n<!-- Image (109, 506, 918, 706) -->\n\n(b) Wing section with beveled-trailing-edge aileron.\n\nNACA\n\nFigure 2.-NACA 66,1-115 airfoil section equipped with unsealed 0.20c plain ailerons of true-airfoil-contour profile and beveled-trailing-edge profile. Chordwise static-pressure orifice locations are shown. c=24 inches.", "timestamp": "2026-07-22T04:43:02.227086+00:00"}
{"citation_id": "19930092013", "source_url": "https://ntrs.nasa.gov/api/citations/19930092013/downloads/19930092013.pdf", "page_number": 16, "total_pages": 21, "image_filename": "19930092013_p16.jpg", "text": "```markdown\n12\nREPORT 948—NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\n<!-- Image (71, 84, 933, 472) -->\n\nFIGURE 14.—Time histories of typical control-fixed lateral oscillations. Cruising condition.\n\nhistories for the cruising condition with effective dihedrals of 24.4°, 6.2° (normal airplane), and zero. It is seen that, with $\\Gamma_e=28.4^\\circ$ in the approach condition, the airplane exhibited slight oscillatory instability.\n\nThe period and damping of oscillations such as those shown in figures 13 and 14 were measured for other dihedral settings and for the high-speed condition. The average values are shown as functions of effective dihedral in figure 15. The time to double amplitude of 38 seconds for the landing-approach condition with 28.4° dihedral is arbitrarily shown in a region of approximately neutral stability. No points are shown for negative $\\Gamma_e$ because, as seen in figure 13, the damping was so high that evaluation of period and damping was virtually impossible.\n\n**Characteristics in rudder-fixed aileron rolls.**—Time histories of typical rudder-fixed aileron rolls for the landing-approach condition with the apparatus set for effective dihedrals of 28.4°, 22.7°, 14.2°, and 5.3° (normal airplane with apparatus inoperative) are shown in figure 16. Similar time histories for the cruising condition with effective dihedrals of 24.4°, 18.2°, 12.9°, and 6.2° are shown in figure 17. It is seen that rolling-velocity reversals occurred in the landing-approach condition with effective dihedrals greater than that of the normal airplane and in the cruising condition with 24.4° effective dihedral.\n\nReduction of these data to the conventional plots of the aileron-effectiveness criterion $pb/2V$ against aileron deflection was not done because the dihedral apparatus is effective over only a limited range of sideslip angle, and the usable aileron deflection during rolls is thereby limited. However, it was estimated from the available data that the $pb/2V$ for full aileron deflection would be well below the required value of 0.07 (references 2 and 3) with the high positive dihedrals in the landing-approach condition.\n\n**Pilots' opinions.**—Figure 18 is a graphic summary of the pilots' opinions of the over-all lateral handling characteristics in which pilots' opinions are shown as a function of effective dihedral.\n\nThe term \"intolerable\" as used here means something worse than objectionable, but does not necessarily mean unflyable. It describes a condition which would be considered dangerous in normal fighter operation.\n\nThe term \"tolerable\" describes a condition which would not be dangerous in normal fighter operation, but which is not necessarily desirable or pleasant.\n\nA \"good\" condition is not only safe, but is also a desirable or pleasant condition.\n\nThe rolling-velocity reversals which occurred in rudder-fixed aileron rolls with high values of effective dihedral (figs. 16 and 17) did not adversely affect the pilots' opinions of the over-all lateral handling characteristics shown in figure 18, although such reversals are unacceptable according to references 2 and 3. One feature of high dihedral which was very desirable to the pilots in the landing-approach condition was the effectiveness of the rudder in producing roll. Thus, for this airplane, the high rate of roll due to the rudder more than offset the low values of rolling velocity, and the reversal in rolling velocity due to aileron deflection. The requirements of references 2 and 3 would, therefore, seem too stringent in this case.\n```", "timestamp": "2026-07-22T04:43:04.824458+00:00"}
{"citation_id": "19930085838", "source_url": "https://ntrs.nasa.gov/api/citations/19930085838/downloads/19930085838.pdf", "page_number": 102, "total_pages": 118, "image_filename": "19930085838_p102.jpg", "text": "100\nNACA RM No. L9B23\n\n<!-- Image (108, 119, 832, 935) -->\n\n(h) $\\delta_f = 40^\\circ$.\nFigure 12.- Continued.", "timestamp": "2026-07-22T04:43:07.308035+00:00"}
{"citation_id": "19930082496", "source_url": "https://ntrs.nasa.gov/api/citations/19930082496/downloads/19930082496.pdf", "page_number": 7, "total_pages": 50, "image_filename": "19930082496_p7.jpg", "text": "```markdown\n6\nNACA TN No. 1836\n\nA specimen was placed in the holder and located in the preheated furnace where it was maintained at the evaluation temperature for 10 minutes, after which it was removed to the quenching-air stream within $\\frac{1}{2}$ to $1\\frac{1}{2}$ seconds and kept there for 5 minutes. The specimens were so placed in the air stream that the flat surfaces were parallel to the flow of air. The quenching air supplied at 85° F flowed at the rate of 50 pounds per minute through a 6-inch-diameter pipe with a velocity of approximately 50 feet per second. Preliminary studies with a thermocouple embedded in a ceramic specimen indicated that with the furnace at 1800° F this procedure resulted in an initial heating rate at the center of the specimen of 140° F per second and an initial cooling rate of 200° F per second. This heating and cooling operation constituted one cycle; the cycle was immediately repeated. While the furnace temperature was being established, the specimen was kept in the air chamber.\n\nA specimen was subjected to 25 temperature cycles with a furnace temperature of 1800° F. If this treatment was successfully survived, 25 cycles were successively repeated with furnace temperatures of 2000°, 2200°, and 2400° F or until failure occurred. The appearance of a crack was considered to be a failure. In those cases in which oxidation occurred and a specimen was believed to have cracked, radiography was used to inspect the base material beneath the oxide surface. Upon completion of the investigation, all specimens were radiographically inspected for internal cracks if surface cracks were not apparent.\n\nQuasi-Service Evaluation\n\nA small gas turbine supplied with hot gases from a turbojet combustion chamber was used for the quasi-service evaluation of the ceramic blades. Gas temperature was measured upstream of the turbine inlet. This apparatus is described in detail in reference 8. This unit was modified by the addition of a 0.031-inch-thick, sheet-metal shield about the turbine, approximately 4 inches from the inner wall of the water-jacket housing. The space between the shield and the housing was filled with graphite asbestos sheet (fig. 5). This arrangement was used to prevent ricocheting fragments of fractured blades from injuring other blades and to preserve fragments. The wheel diameter was approximately 9.5 inches and the blades extended about 1.3 inches beyond the wheel. The wheel was dynamically balanced before it was installed in the turbine case and thereafter whenever rebalancing appeared necessary.\n```", "timestamp": "2026-07-22T04:43:08.240767+00:00"}
{"citation_id": "19930082447", "source_url": "https://ntrs.nasa.gov/api/citations/19930082447/downloads/19930082447.pdf", "page_number": 17, "total_pages": 24, "image_filename": "19930082447_p17.jpg", "text": "NACA TN No. 1775\n\n15\n\n[Figure: A black-and-white photograph of a metallic float model mounted on a test rig. The model is elongated and curved, with visible rivets and seams. To the left is part of a mechanical support structure with pipes and brackets. In the upper right corner of the image, there is a small label reading “NACA L-54869.1”. Below the image, centered, is the caption:]\n\nFigure 2.- Langley impact-basin float model N-3.", "timestamp": "2026-07-22T04:43:08.331733+00:00"}