Show all work, Highlight your Answers and use English units (Be sure to round to the 4\"1 decimal point for #5-7, so .9612 instead of .96) Name of your selected airfield: and include the following: 1. ICAO identifier (the ICAO identifier is the 4-letter airport code, starting with a 'K' for the continental US): 2. Field elevation [ft MSL]: (eld elevation can be found in the location information section at yvectomom or the overview section at AOPA's port Directory https://www.aopa.orgldestinationsl) 3. Current weather report at the time of work on this assignment to include: 0 Date and time 0 Current altimeter setting [in Hg]: 0 Current temperature [F or C, but stay consistent]: -Note: When operating at an airfield within the US, the altimeter is adjusted according to current conditions (i.e. the reported altimeter setting that you found) in order to always indicate the correct field elevation when on the ground. Therefore, your indicated altitude will remain equal to your eld elevation when being on the surface of that airfield, but your pressure altitude will be subject to change depending on changes in the altimeter setting. 4. Using your researched data, find the Pressure Altitude of your airfield [ft]. 0 Use the found altimeter setting and the rule of thumb lapse rate OH in Hg = 1000 ft, i.e. 00.01 in Hg = 10 ft change from the eld elevation, with standard atmospheric altimeter setting being 29.92 in Hg (see also tutorial and example problems, always subtract the current Altimeter setting from 29.92). Keep in mind that an increase in altimeter setting above standard will lead to a positive shift of Indicated Altitude above Pressure Altitude (or in other words, a lower pressure altitude than what is indicated) and vice versa. 0 Note: In some cases (low field elevation, coupled with high altimeter setting) it may lead to negative pressure altitudes, which is completely correct. However, to allow further work in the atmospheric table excerpt in your textbook (Table 2.1, which does not include the negative values), you may change your altimeter setting in question 3 to a lower value (please include a note) for all further work or select a different aireld (preferably above 1000' MSL). 5. Based on your determined pressure altitude, find the Pressure Ratio, (delta), in the Standard Atmosphere Notice that the above relationships between Indicated, Pressure, Temperature, and Density Density Altitude Calculator Altitudes hold for any point in the atmosphere, not just for aircraft on the surface of an airfield. If atmospheric conditions such as altimeter setting and temperature or temperature offset are Elevation known, any Indicated Altitude can be converted in a similar way. feet . meters 4472 Air Temperature O deg F O deg C One aspect that wasn't addressed so far in our calculations is humidity. Although not part of the Altimeter Setting O inches Hg OhPa 29.87 in "Flight Theory and Aerodynamics" introduced Standard Atmospheric table, changes in humidity can greatly influence Density Altitude and lead to decreases in performance of the Relative Humidity 9% engines, for example. Calculate Reset 10. To highlight the influence of humidity on air density, enter your airfield (elevation) and weather data (temperature and altimeter setting) into the online density altitude calculator tool Density Altitude 7457 2273 meters http://wahiduddin.net/calc/calc da rh.htm (Make sure to select the correct units in the top/input area of the calculator and read the correct units in the bottom/results area) Absolute Pressure 25.348 inches Hg 858.38 hPa Air Density 0.0611 1b/fts 0.979 kg/mg Relative Density 79.94 79.94 % 10A. Find Density Altitude [ft] with 0% relative humidity. 7457' Estimated AWOS 7500 feet 2286 meters 10B. Find Density Altitude [ft] with 100% relative humidity. Copyright 1958-2015, Richard Shelquist 8151' 10C. Compare your findings 9A) and 9B). Describe what effects humidity has on air density. "Linear relationship, as humidity increases, so does DA, therefore Density Altitude Calculator performance decreases In the second part of this module's assignment we will revisit our takeoff conditions from Elevation feet . meters 4472 module 1. This time, we will take a closer look into the speeds involved. Let's assume the given Air Temperature O deg F . deg C 90 150 kis lift-off speed was the indicated value in the cockpit, i.e. the Indicated Airspeed [KIAS]. Altimeter Setting O inches Hg .hPa 29.87 11. Find the Calibrated Lift-Off Speed (KCAs) using the chart below (150 KIAS), which is a Relative Humidity 100 typical example of an aircraft position error correction chart. (Consider that the gear would obviously still be in the down position at lift-off - "Landing Configuration"). CAS - Calculate Reset Density Altitude 8151 Feet 2484 meters TYPICAL POSITION ERROR CORRECTION Absolute Pressure 25.348 inches Hg 858.38 hPa LANDING CONFIGURATION Air Density 0.0598 1b/ftg 0.958 kg/m3 Relative Density 78.24 78.24 9% AVi , KNOTS Estimated AWOS 7500 feet ERROR CORRECTION 2286 meters AIRSPEED POSITION CAS = IAS + AVI -104 506 METARs from this airport: INDICATED AIRSPEED, KNOTS KOGD 6:53 PM 120 @ 4 kts 30 /41 VFR (42 minutes Visibility: 10.0 2.2'75.0' CAS = 150 kts +2.5 = 152.5 kts 4 4438 ago) Clear 2987 MSL Table 2.1. Standard Atmosphere Table 12. Find the Equivalent Lift-Off Speed (KEAS) using your Calibrated Airspeed from 10 above and the Pressure Altitude for your selected airfield (from 5). (Compressibility Correction Chart, Altitude Density of Somed Viscosity. see "Flight Theory and Aerodynamics", Fig. 2.6). Is the Compressibility negligible, why? Ratio, KEAS =_ 59.00 1.0000 661.7 0.9711 $5.43 1660 659.5 CAS ~ EAS = 153 KEAS 657.2 654.9 Compressibility WAS negligible at such low speeds 09450 0629 626.7 0.5328 7299 0.4595 0610229 8VC, "NOTS AIRSPEED ROR CORRECTION AV, KNOTS SPEED POSITION 300 CALIBRATED AIRSPEED, KNOTS CAS . IAS + AVI 260 INDICATED AIRSPEED, KNOTS 13. Find the True Lift-Off Speed (KTAS) (use the Density Ratio o found in 8). TAS= Figure 2.6 Position error correction chart (from ref. 28). TAS = EAS / SQRT(sigma) = 153/v.8001 = 171 KTAS EQ 2.12 COMPRESSIBILITY CORRE 14. Calculate the Dynamic Pressure 'q' [Ib/ft ], based on the TAS above. (Dynamic Pressure definition and formula can be reviewed in "Flight Theory and Aerodynamics" page 22; make 30 EAS . CAS + AV. sure to use a formula consistent with a Lift-Off Speed in kts). M = 100 q = sigma*EAS^2/295 = 78 ps COMPRESSIBILITY CORRECTION AVC, KNOTS AIRSPEED 30.0 60,000 EQ 2.10 10.000 5,000 ALTITUDE SEA LEVEL FT. Fig 2. 10 100 200 300 400 500 600 CALIBRATED AIRSPEED, KNOTS 5Pressure Ratio, (delta), in the Standard Atmosphere Table (\"Flight Theory and Aerodynamics\Show all work and Highlight your Answers 1. Find the Calibrated Lift-Off Speed [KCAS] for 150 KIAS using the chart below, which is a typical example of an aircraft position error correction chart. (Consider that the gear would obviously still be in the down position at lift-off, so use the Landing Configuration Line). TYPICAL POSITION ERROR CORRECTION LANDING CONFIGURATION +5: ERROR CORRECTION AVi, KNOTS AIRSPEED POSITION CLEAN CONFIGURATION CAS = IAS + AVi -10# 260 360 460 560 INDICATED AIRSPEED, KNOTS 2. Find the Equivalent Lift-Off Speed [KEAS] using your Calibrated Airspeed from #1 above and the Pressure Altitude for your selected airfield (from A). (Compressibility Correction Chart see "Flight Theory and Aerodynamics," Fig 2.12). Comment on your findings. Why was/wasn't the Compressibility Effect in your case negligible? 3. Find the True Lift-Off Speed [KTAS] (use the Density Ratio in question #7 of the Airspeed Exercise Part 1 document). 4. Calculate the Dynamic Pressure 'q' [lb/ft2=psf], based on the TAS above. (Dynamic Pressure definition and formula can be reviewed in "Flight Theory and Aerodynamics" textbook (EQ 2.1); make sure to use a formula consistent with a Lift-Off Speed in kts.Pressure Ratio. If you are trying to find pressure ratio at sea level or at altitude where you know the actual pressure of your altitude, then use the equation: Pressure Ratio (delta) = Pactual / Pssl 8(delta) = P / PO this EQ only works at Sea Level! This problem asks for Pressure ratio at Pressure Altitude of 15,000 ft. If you know the Pressure ratio then you know the pressure altitude and vice versa. If you know the pressure ratio you know what the actual pressure is compared to Standard sea level day. Barometric Altimeter setting is the pressure at sea level not at 15,000 ft. So read off the table at 15,000 ft Pressure ratio. Temperature ratio is Tact / T ssl. Temperature at your conditions at altitude vs. temp at sea level standard day. Standard at altitude is not the same as standard at sea level. Standard at 15,000 ft is 5.51 deg F, so standard +5 deg is 10.51 deg F. Convert that to Rankine: 10.51 +460 = 470.51. Standard at sea level is 460 +59 = 519. Density ratio is Pressure Ratio / Temperature ratio = Now if you know density ratio you can find density altitude using interpolating from chart. Calibrated Airspeed = Indicated Airspeed +/- Position error Chart on exercise is an example aircraft profile. Now, no standard airspeed gauge reads in % knots increments. But I will keep the % knot in case there are more *% knot corrections that need to be made. Equivalent Airspeed = Calibrated Airspeed - Compressibility Correction Compressibility correction is found on Fig 2.6. This is good for all aircraft. Correction is always negative. EAS