advertisement

E6-B Flight Computer E6-B Flight Computer • E6-B has two main parts: – a slide rule side for making quick calculations. – a wind side for computing ground speed and wind correction angle. • The slide portion of the circular slide rule side also includes quick reference material. The Slide Rule Side • This side consists of a rotating disk and a fixed portion • There are three set of scales outer scale (on the fixed portion) middle scale and inner scale (on the disk) • The slide rule side also has “windows” that will use to solve altitude and airspeed problems. outer scale middle scale inner scale windows The Slide Rule Side • When set numbers on the middle scale against numbers on the outer scale, allows you to solve problems of - time - speed - distance - fuel consumption - conversions between measurements • The inner scale on the rotating disk is graduated in hours. The Slide Rule Side • Number 60 on the rotating disk is marked differently than the other numbers and called “the rate arrow”. • That is because most of the problems will be concerned with time—“something” per hour, either miles or gallons. rate arrow How to read and interpret the numbers on the slide rule side. • Rotate disk until all numbers on middle scale match up with numbers on outer scale , put 10 on the top. • Number “10” may be read as “.1,” “1,” “100,” or “1,000” depending on context of the problem. • For now, read it as 10. The next number to the right is 11, so each mark between the two numbers is equal to .1, and you would read them as 10.1, 10.2, 10.3, etc. How to read and interpret the numbers on the slide rule side. • If you were solving a problem involving 1,000 pounds of fuel. • The number 10 would be read as 1,000, and each mark would be equal to 10 pounds, and the 11 would be read as 1,100 pounds. How to read and interpret the numbers on the slide rule side. • Between 15 and 16 each mark is equal to .2 and would be read as 15.2, 15.4, etc. • If you were solving a problem with an airspeed of 150 knots, the first mark past 15 (150 in this case) would be 152. Time, Speed, and Distance Problems • The rate arrow on the disk is always set to indicate a value per hour on the outer scale. • There are three basic time-speed-distance problems. • In two of these problems you know the rate, while in the third problem, the rate is part of the answer. Time, Speed, and Distance Problems • Find the Time En Route : given g/s 150 knots, distance 245 nm. 1. Set the rate arrow at 150 on outer scale. 2. 245 nm. is halfway between 24 and 25 on the outer scale. (Speed and distance are always on the outer scale) 3. Look directly opposite to that value on the inner scale to find the Time En Route ; answer = 1:38 Time, Speed, and Distance Problems • Find distances you can go : given g/s 125 kts, fuel endurance 4.5 hrs. 1. Set the rate arrow at 125 on outer scale. 2. Find 4:30 on inner scale. 3. Look opposite value on outer scale to find the distance ; answer = 564 nm. (not 56.4 or 5640….use commonsense) Time, Speed, and Distance Problems • If you fly cover distance of 26 nm. within 13 min. ; Find airspeed. 1. Set 13 min. on middle scale opposite to 26 on outer scale. 2. Find ground speed from rate arrow ; answer = 120 kts. Time, Speed, and Distance Problems • Practice Speed Time Distance 125 kts 4:12 ____ 524 nm 138 kts ____ 2:30 345 nm 110 kts 1:40 183 nm ____ Fuel Consumption Problems • Problems involving fuel endurance , fuel consumption, and fuel capacity are solved using the same numbers used in the time-speed-distance problems. Only the names change. fuel endurance fuel consumption fuel capacity = = = time speed distance Fuel Consumption Problems POH indicates fuel consumption of 8.4 gallons per hour at a given power setting, usable fuel capacity is 64 gallons. How many hours endurance do you have in the tanks ? 1. Set rate arrow at 8.4 on outer scale. 2. Find 64 on outer scale 3. Opposite of 64, read fuel endurance in hours:7:37 on the inner scale. • Note : outer scale which was used for speed and distance, is now used to indicate gal./hrs. and fuel capacity. Conversions • You can use E6-B to convert between values by settings of the middle scale. Nautical to Statute Miles Problem : convert 90 knots to statute miles per hour: 1. Set the arrow marked NAUT opposite of 90 on the middle scale. 2. Read 103.5 under the STAT arrow. Conversions Nautical or Statute Miles to Kilometers Problem : convert 115 statute miles to kilometers: 1. Set 115 opposite of the STAT arrow. 2. Read 185 under the KM marking. Conversions U.S. Gallons to Imperial Gallons Problem : convert 64 U.S. Gallons to Imperial Gallons : 1. Line up U.S. GAL arrow on middle scale opposite IMP. GAL arrow on outer scale. 2. Find 64 on the middle scale 3. Read 53.2 Imperial gallons on the outer scale Conversions Quantity/Weight Conversions Fuel U.S. Gallons to Fuel LBS. Problem : convert fuel 32 U.S. Gallons to LBS : 1. Line up U.S. GAL arrow on middle scale with FUEL LBS arrow on outer scale. 2. Find 32 on the middle scale 3. Read 192 LBS on the outer scale Quantity/Weight Conversions Oil U.S. Gallons to Oil LBS. Problem : convert oil 2 U.S. Gallons to LBS : 1. Line up U.S. GAL arrow on middle scale with OIL LBS arrow on outer scale. 2. Read 15 pounds on the outer scale opposite of 2 gallons (20 mark) on the middle scale. Quantity/Weight Conversions • Use the same method for converting Imperial Gallons of fuel / oil to LBS. • You can also convert - liters to U.S. gallons, - pounds to kilograms, - feet to meters by aligning the appropriate arrows on the middle and outer scales. Using the Altitude and Speed Correction Windows • Finding True airspeed (TAS) : IAS CAS temperature correct for pressure altitude and TAS • To get pressure altitude set altimeter to 29.92 and read the altitude indicated; • On E6-B the outer scale is marked TAS (true airspeed) and the middle scale is marked CAS (calibrated airspeed). Using the Altitude and Speed Correction Windows Finding True airspeed (TAS) and Density alttitude : Problem : CAS 143 kts, Pressure alt 15,000 ft, OAT -15ºC : Find TAS 1. Set pressure alt 15,000 ft. in the window (right) opposite OAT -15ºC 2. Without moving the computer’s scales, read the true airspeed on the outer scale opposite CAS 143 kts. on the middle scale.: answer 183 kts. Using the Altitude and Speed Correction Windows Finding True airspeed (TAS) and Density alttitude : 3. Read the density altitude over the arrow in the DENSITY ALTITUDE window. : answer 15,000 ft. Note : Density alt. is Pressure alt. corrected for variation from standard pressure. Standard Condition Pa = Da , Above standard Da > Pa , Below standard Da < Pa Standard : Temp. decrease 2ºC per 1,000 ft. Using the Altitude and Speed Correction Windows Finding True Alttitude : (Unknown Station alt.) Problem : Pressure alt. 8,000 ft, Indicate/Calibrated alt.7,600 ft , Temp -15ºC : Find True alt. 1. Set pressure alt 8,000 ft. in the window (left) opposite -15ºC 1. Read True airspeed on the outer scale opposite Indicate/Calibrated alt. 7,600 ft on the middle scale. : answer 7,600 ft . Using the Altitude and Speed Correction Windows Finding True Alttitude : (known Station alt.) Problem : Pressure alt. 12,000 ft, Indicate/Calibrated alt.11,000 ft , Temp -30ºC, Station alt. 3,000 ft : Find True alt. 1. Set pressure alt 12,000 ft. in the window (left) opposite -30ºC 2. Subtract station altitude 3,000 ft. from indicated/calibrated altitude 11,000 ; get calibrated altitude of 8,000 ft. AGL. 3. Find calibrated altitude 8,000 ft. AGL on the middle scale and read the correction to station altitude on the outer scale = 7,350 ft. 4. Add the correction to station altitude 3,000 ft. to get true altitude MSL. Answer : 10,350 ft. Off-Course Problems After flying 125 miles, you note that you are 8 miles off course. By using E6-B, you can determine : Degree to fly parallel (α) 235 nm Degree to intercept (β) β α 8 nm 125 nm Add these two = total degree correction (α+β) Off-Course Problems After flying 125 miles, note that flown 8 miles off course. Find Degree to fly parallel (α) 235 nm 1. Set Miles traveled 125 nm. on middle scale to line up with Distance Off 8 nm. on outer scale. 2. Read 3.7 on rate arrow ; α = 3.7º Find Degree to intercept (β) β α 1. Set Miles to go 235 nm. on middle scale opposite Distance Off 8 nm. on outer scale. 2. Read 2.4 at the rate arrow ; β = 2.4º 8 nm 125 nm Total correction (α+β) = 3.7 + 2.4 = 6.1º Off-Course Problems 235 nm α β α 8 nm 125 nm β The Crosswind Table • Used to determine headwind, tailwind or crosswind component • must know - angle between your course and reported wind direction. - reported wind velocity. The Wind Side of the Slide Instructions Determine ground speed and wind correction angle must know: • true course : measured directly on chart • true airspeed : converted from indicated airspeed in flight or taken from POH during preflight planning. • true wind direction and velocity : winds aloft forecast Determine ground speed and wind correction angle Problem : TC 090, TAS 125 kts., Wind 230/18 : Find G/S, WCA 1. Set Wind direction 230º at TRUE INDEX. 2. measure 18 units up from the grommet toward the TRUE INDEX and make a dot 3. Rotate transparent disk to bring TC 090º to TRUE INDEX. 4. Move the slide until wind dot falls on the arc for TAS 125 knots 5. Read ground speed of 138 knots under grommet (wind dot is below grommet indicates a tailwind) 6. The wind dot is 5º to the right, indicating that the true heading should be 095º : WCA = +5 , TH = 095 PRACTICE Wind Wind Direc. Velocity TC TAS TH G/S 1. 240 38 300 165 288 ____ 143 ____ 2. 040 43 150 140 133 ____ 149 ____ 3. 330 25 020 180 014 ____ 163 ____ Determining Winds in Flight Problem : TC 180, TH 160, G/S 120 kts., TAS 140 kts. : Find Wind 1. Set TC 180 at TRUE INDEX. 2. Move slide until grommet falls over line marked G/S 120 kts. TH is 20° less than TC, means 20° left WCA. 3. With grommet on 120kts. G/S line, find the point on slide where 20° left WCA crosses the line marked 140 and make a pencil mark. 4. Rotate disk until pencil mark is on centerline between grommet and true index. 5. Determine wind velocity by counting the lines between grommet and pencil mark. 6. Read wind direction under true index. Answer : wind 104/50 PRACTICE TH TC TAS G/S Wind Wind Direc. Velocity 1. 320 315 140 128 002 ____ 17 ____ 2. 175 160 150 115 212 ____ 49 ____ Exercise Plan flight from VTBT - VTPH - Ko Lan – VTBU – VTBT Used : 4,500 ft. for West bound / 5,500 ft. for East bound Wind forecast 060/20 Temp 25ºC TAS 93 kts. (with p/w setting 2,500 rpm.) Variation 2º W Deviation 0º Fuel on board 22.5 Gallons Consumption 4.8 Gal./hrs. Fuel used for Start/Taxi/Take off = 1.2 Gallon Produce : Aero Chart & Flight Log