ASCI 309 LIGAREE 2.3 AERO

pptx

School

Embry-Riddle Aeronautical University *

*We aren’t endorsed by this school

Course

309

Subject

Mechanical Engineering

Date

Apr 3, 2024

Type

pptx

Pages

Uploaded by MagistrateStraw13063

1 AVIATION SAFETY PROGRAM MANAGEMENT EMBRY RIDDLE AERONAUTICAL UNIVERSITY LIGAREE. 2.3

2 ASCI 309 Standard Atmosphere – Airspeed Exercise Part 1 Appendix A

3 ASCI 309 Standard Atmosphere – Airspeed Exercise Part 1 Exercise Guidelines Show all work, highlight your Answers and use English units Name of your selected airfield and include the following: KAVL 2. Field elevation [ft MSL]: 2164 ft MSL 3. Current weather report at the time of work on this assignment to include: o Date and time: 0029 UTC 4/1/22 o Current altimeter setting [in Hg]: 30.18 in Hg o Current temperature [°F or °C, but stay consistent]: 77.0°F 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 field 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]. o Use the found altimeter setting and the rule of thumb lapse rate of 1 in Hg = 1000 ft, i.e. 00.01 in Hg = 10 ft change from the field elevation, with standard atmospheric altimeter setting being 29.92 in Hg (see also tutorial and example problems). 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. o 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 airfield (preferably above 1000’ MSL). Pressure altitude = (Std pressure – current pressure) x 1000 + field : Asheville Regional Airport 1. ICAO identifier:

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

4 elevation. (29.92 in Hg – 30.18 in Hg) x 1000 + 2164 ft MSL = PA (-0.26) x 1000 + 2164 = PA -260 + 2164 = PA 1904 = PA 1904 ft 5. Based on your determined pressure altitude, find the Pressure Ratio , δ (delta), in the Standard Atmosphere Table (“Flight Theory and Aerodynamics”, Table 2.1 – the formula will not work, you must use Table 2.1). Interpolate as necessary. Pressure ratio = Actual pressure alt / Pressure alt at Standard sea level Pressure ratio = 30.18 / 29.92 = 1.009 According to Table 2.1 the pressure ratio 0.9298 δ ( delta ) 6. Using your researched current temperature and the known standard sea- level temperature, determine the Temperature Ratio , θ (theta). (Remember to convert °F or °C into an absolute temperature, i.e. °R or °K, and stay consistent within one system of measurement.) Temp Ratio = Current temp / at Standard sea level Current temp is 77 ℉ Covert to °K (77 ℉ - 32) x 5/9 + 273.15 °K = 298.15 °K 298.15 / 284.15 = 1.049 θ ( theta ) 7. From your #5 and #6 results, find the Density Ratio , σ (sigma). Density ratio = Pressure ratio / Temp ratio 0.9298 / 1.049 = 0.8864 σ ( sigma ) 8. With your result, from #7, re-enter the Standard Atmosphere Table (“Flight Theory and Aerodynamics”, Table 2.1) to find the corresponding Density Altitude . Interpolate as necessary. y = y 0 + (y 1 – y 0 ) (x – x 0 / x 1 – x 0 ) σ = 0.8864 (x)

5 At 2000 ft (y 0 ): σ = 0.9428 (x 0 ) At 3000 ft (y 1 ): σ = 0.9151 (x 1 ) y = 2000 + (3000 – 2000) (0.8864 – 0.9428 / 0.9151 – 0.9428) y = 4036.10 ft 9. To highlight the influence of humidity on air density, enter your airfield (elevation) and weatherdata (temperature and altimeter setting) into the Density Altitude Calculator (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). **Screenshot and paste your Density Altitude Calculator twice, the first when set to 0% humidity and the second when set to 100% humidity** A. Find Density Altitude [ft] with 0% relative humidity : 3517 ft B. Find Density Altitude [ft] with 100% relative humidity : 3942 ft

6 C. Compare your findings I) and II). Describe what effects humidity has on Air Density : As the humidity increased the density altitude increased. This is due to the effects of humidity. The effect of moisture due to the fact that water vapor is lighter than air, so moist air is lighter than dry air. As the amount of water vapor increases, the density in the air decreases, resulting in a higher density altitude (decrease in aircraft performance). Continue to Next Page!

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

7 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). CAS = 150 + 2.5 CAS = 152.5 KCAS 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 2.10). Comment on your findings. Why was/wasn’t the Compressibility Effect in your case negligible? EAS = CAS +/- ΔV C EAS = 152.5 + 0 = 152.5 Low flight and low airspeeds with a 0-airspeed compressibility correction there is negligible correction which make it unimportant at these speeds. This would be a different outcome at higher speeds . 3. Find the True Lift-Off Speed [KTAS] (use the Density Ratio in question #7 of the Airspeed Exercise Part 1 document). TAS = EAS / √ σ = 152.5 / 0.8864 = 172.04 TAS 4. Calculate the Dynamic Pressure ‘q’ [lb/ft2], based on the TAS above. (Dynamic Pressure definition and formula can be reviewed in “Flight Theory and

8 Aerodynamics” page 22 (EQ 2.1); make sure to use a formula consistent with a Lift-Off Speed in kts. q = σ (V K 2 ) / 295 = 0.8864 (172.04 2 ) / 295 = 88.93 lb/ft 2