1 00:00:16,720 --> 00:00:19,120 PHILIP GREENSPUN: All right, so a complicated aircraft 2 00:00:19,120 --> 00:00:20,930 will have a lot of systems. 3 00:00:20,930 --> 00:00:23,200 These are the systems from the Canadair Regional Jet. 4 00:00:28,490 --> 00:00:29,630 How well did that I fly it? 5 00:00:29,630 --> 00:00:32,259 We landed it once in Toronto, and I was doing this, 6 00:00:32,259 --> 00:00:34,140 and the captain said to me, well-- 7 00:00:34,140 --> 00:00:36,020 he was a young guy-- 8 00:00:36,020 --> 00:00:38,660 he said, well, you know nobody was born knowing how to fly 9 00:00:38,660 --> 00:00:40,570 a 53,000-pound jet. 10 00:00:40,570 --> 00:00:42,260 But anyway, this is the kind of stuff 11 00:00:42,260 --> 00:00:44,570 you have to learn for the big aircraft. 12 00:00:44,570 --> 00:00:46,400 Here are these systems that we're 13 00:00:46,400 --> 00:00:48,695 going to talk about that you have on a small aircraft. 14 00:00:52,260 --> 00:00:54,160 The engine, first of all, what are the types? 15 00:00:54,160 --> 00:00:56,520 You might remember the cool old days. 16 00:00:56,520 --> 00:00:59,340 You had these big radio engines, and they 17 00:00:59,340 --> 00:01:03,540 went up to 3,500 horsepower, I think, was the biggest one. 18 00:01:03,540 --> 00:01:05,489 But your typical World War Ii fighter 19 00:01:05,489 --> 00:01:08,730 might have a 2000 horsepower-ish radial engine. 20 00:01:08,730 --> 00:01:11,610 Turboprops, so we'll get into this more. 21 00:01:11,610 --> 00:01:15,450 I have a special lecture on turbines and multi-engine. 22 00:01:15,450 --> 00:01:19,680 But it's a jet engine that's hooked into a propeller, 23 00:01:19,680 --> 00:01:23,250 and that lets you land on shorter runways, 24 00:01:23,250 --> 00:01:27,390 and it's more fuel-efficient at lower altitudes. 25 00:01:27,390 --> 00:01:30,150 The popular examples, the Pratt & Whitney PT6 26 00:01:30,150 --> 00:01:32,600 has been around since the 50s. 27 00:01:32,600 --> 00:01:36,210 A competitor from the similar era was designed by Garrett. 28 00:01:36,210 --> 00:01:38,370 Those have typically slugged it out. 29 00:01:38,370 --> 00:01:43,080 One of them is a free turbine, so you have the PT6. 30 00:01:43,080 --> 00:01:46,410 And this is a GE Walter derivative, that they now 31 00:01:46,410 --> 00:01:48,630 call the GE Advanced Turboprop. 32 00:01:48,630 --> 00:01:50,640 So the cold air comes in. 33 00:01:50,640 --> 00:01:53,730 It gets burned. 34 00:01:53,730 --> 00:01:58,920 And the hot exhaust gases spin this power 35 00:01:58,920 --> 00:02:04,020 turbine which has a shaft that drives the compressor. 36 00:02:04,020 --> 00:02:06,330 And it also goes back this way. 37 00:02:10,544 --> 00:02:12,090 There's a second. 38 00:02:12,090 --> 00:02:14,460 I think one of them drives the compressor, 39 00:02:14,460 --> 00:02:16,530 and there's a second wheel there that 40 00:02:16,530 --> 00:02:21,120 is exposed to the hot gases and it will drive the propeller. 41 00:02:21,120 --> 00:02:24,780 So there's kind of a fluid coupling there through the air. 42 00:02:24,780 --> 00:02:30,540 Whereas the Garrett Honeywell product has a direct drive 43 00:02:30,540 --> 00:02:32,775 transmission that's more complicated but also 44 00:02:32,775 --> 00:02:34,150 a little bit more fuel-efficient. 45 00:02:34,150 --> 00:02:37,470 So those are the two big designs. 46 00:02:37,470 --> 00:02:41,940 You get a lot more reliability with a turboprop 47 00:02:41,940 --> 00:02:43,060 if you need power. 48 00:02:43,060 --> 00:02:46,590 It's hard to make a piston engine reliable if it generates 49 00:02:46,590 --> 00:02:48,270 a lot of horsepower. 50 00:02:48,270 --> 00:02:51,360 The disadvantage is nobody's really figured out 51 00:02:51,360 --> 00:02:54,300 how to make these things for less than half a million 52 00:02:54,300 --> 00:02:56,680 dollars new in a box. 53 00:02:56,680 --> 00:02:59,790 And the most popular airframes for the turboprop 54 00:02:59,790 --> 00:03:02,970 for things that you might fly, the Beechcraft King 55 00:03:02,970 --> 00:03:05,330 Air which is twin-engine, and the Pilatus 56 00:03:05,330 --> 00:03:07,410 PC-12 which is a single. 57 00:03:07,410 --> 00:03:11,850 Turbojets, which-- well, the FAA calls them turbojets. 58 00:03:11,850 --> 00:03:14,790 They're really turbofans because of the bypass air. 59 00:03:14,790 --> 00:03:17,710 We'll see that in the next slide. 60 00:03:17,710 --> 00:03:19,710 These are-- one thing to remember about them 61 00:03:19,710 --> 00:03:21,070 is they're normally aspirated. 62 00:03:21,070 --> 00:03:23,520 They actually do produce less and less power 63 00:03:23,520 --> 00:03:25,950 as you get up to higher altitudes which 64 00:03:25,950 --> 00:03:30,900 is important for taking off, you know, in Colorado on a hot day. 65 00:03:30,900 --> 00:03:33,270 You have much lower noise and vibration-- 66 00:03:33,270 --> 00:03:36,390 maybe not if you mount one of them right over your ear. 67 00:03:36,390 --> 00:03:38,490 That's a Cirrus jet which is kind 68 00:03:38,490 --> 00:03:43,470 of a cool simple personal jet. 69 00:03:43,470 --> 00:03:46,170 They actually have sort of taken over the market starting 70 00:03:46,170 --> 00:03:49,680 in model airplanes going all the way up to the Boeing's 71 00:03:49,680 --> 00:03:50,760 and the airbuses. 72 00:03:50,760 --> 00:03:54,690 And the only gap where turbojets have not taken over 73 00:03:54,690 --> 00:03:56,850 is in your family airplane, right? 74 00:03:56,850 --> 00:03:58,890 Your four-seater, your six-seater, 75 00:03:58,890 --> 00:04:00,690 that's where nobody's figured out 76 00:04:00,690 --> 00:04:03,090 how to make a turbojet that really 77 00:04:03,090 --> 00:04:06,060 makes economic sense or even sense for the range. 78 00:04:06,060 --> 00:04:10,050 They tend not to be as efficient at these low-power settings. 79 00:04:10,050 --> 00:04:13,600 The smaller the turbojet, the less efficient it has been, 80 00:04:13,600 --> 00:04:14,860 unfortunately. 81 00:04:14,860 --> 00:04:16,529 So you wouldn't get the kind of range 82 00:04:16,529 --> 00:04:18,660 that you'd get out of a Cirrus or a Cessna 83 00:04:18,660 --> 00:04:22,060 if you stuck a jet engine in there. 84 00:04:22,060 --> 00:04:23,410 These are more vulnerable. 85 00:04:23,410 --> 00:04:27,750 A bird will usually just get Cuisinarted by a propeller, 86 00:04:27,750 --> 00:04:32,160 but if it goes into the jet engine then it can destroy it. 87 00:04:32,160 --> 00:04:37,190 So the single-engine jet, well, some single-engine jets 88 00:04:37,190 --> 00:04:39,980 like fighters they should have an ejection seat. 89 00:04:39,980 --> 00:04:42,560 The Cirrus single-engine jet has a parachute 90 00:04:42,560 --> 00:04:45,170 for the whole aircraft to float you down. 91 00:04:45,170 --> 00:04:48,290 All right, turbojet, again, this is not really on the exam 92 00:04:48,290 --> 00:04:50,015 but it's just good general knowledge. 93 00:04:52,750 --> 00:04:54,410 The fresh air, it comes in here. 94 00:04:54,410 --> 00:04:56,030 It gets compressed by the compressor. 95 00:04:56,030 --> 00:04:57,800 Once again, that's normal aspiration, 96 00:04:57,800 --> 00:04:59,660 and so it's just a fixed-compression ratio. 97 00:04:59,660 --> 00:05:03,970 It doesn't get more extreme like with the turbocharger 98 00:05:03,970 --> 00:05:06,260 in a piston engine at higher altitude. 99 00:05:06,260 --> 00:05:07,547 Notice this bypass air. 100 00:05:07,547 --> 00:05:09,380 It's being spun, and that blade in the front 101 00:05:09,380 --> 00:05:12,730 is really acting like a propeller. 102 00:05:12,730 --> 00:05:15,350 Here is where the compressed air gets burned and drives 103 00:05:15,350 --> 00:05:19,340 these power turbines that drive the compressor 104 00:05:19,340 --> 00:05:20,990 and the fan in front. 105 00:05:20,990 --> 00:05:23,840 So it seems like a really simple design, 106 00:05:23,840 --> 00:05:27,990 but there's a tremendous amount of engineering in the blades. 107 00:05:27,990 --> 00:05:31,040 And if anything is fabricated just slightly wrong, you know, 108 00:05:31,040 --> 00:05:33,450 the whole thing comes apart and explodes. 109 00:05:33,450 --> 00:05:35,360 So that's one reason I think they're 110 00:05:35,360 --> 00:05:40,560 in the million-dollar range for a typical business jet engine. 111 00:05:40,560 --> 00:05:43,080 All right, so let's go back to our world, which, 112 00:05:43,080 --> 00:05:46,770 unfortunately, is going to be the reciprocating piston engine 113 00:05:46,770 --> 00:05:48,460 kind of like in your car. 114 00:05:48,460 --> 00:05:51,023 The designs-- I don't know-- 115 00:05:51,023 --> 00:05:52,440 the fundamentalists may or may not 116 00:05:52,440 --> 00:05:54,065 have changed that much since the Wright 117 00:05:54,065 --> 00:05:56,880 brothers, but certainly, the designs 118 00:05:56,880 --> 00:05:58,860 that are in your modern Cessna or a Piper-- 119 00:05:58,860 --> 00:06:01,700 the basic geometry, the engine design-- 120 00:06:01,700 --> 00:06:03,625 is really all from the 1950s. 121 00:06:03,625 --> 00:06:06,000 The good news is that with numerically-controlled machine 122 00:06:06,000 --> 00:06:07,620 tools and such, they're much more 123 00:06:07,620 --> 00:06:09,960 reliable than they used to be. 124 00:06:09,960 --> 00:06:12,450 Engine failure was an everyday event 125 00:06:12,450 --> 00:06:14,340 at a busy airport in the old days. 126 00:06:14,340 --> 00:06:18,390 And now, you know, I've flown for, I don't know, 127 00:06:18,390 --> 00:06:23,190 4,000-plus hours with Pistons and have never had any kind 128 00:06:23,190 --> 00:06:24,900 of real engine problem. 129 00:06:24,900 --> 00:06:28,060 The horizontal opposition supposedly smooths things out. 130 00:06:28,060 --> 00:06:30,300 They may ask you about that on the test. 131 00:06:30,300 --> 00:06:32,880 Like the turbojet, it's normally aspirated, 132 00:06:32,880 --> 00:06:35,640 so the performance degrades as you 133 00:06:35,640 --> 00:06:40,020 go to hot and high elevations where the air is thinner. 134 00:06:40,020 --> 00:06:44,160 We'll talk about that in the performance calculations. 135 00:06:44,160 --> 00:06:46,830 You directly drive the propeller. 136 00:06:46,830 --> 00:06:50,220 So if the engine's spinning at 2,500 RPM, 137 00:06:50,220 --> 00:06:52,140 the propeller's spinning at 2,500 RPM. 138 00:06:52,140 --> 00:06:54,370 There's no transmission. 139 00:06:54,370 --> 00:06:57,420 The cooling is the air, it's called air-cooled. 140 00:06:57,420 --> 00:06:59,610 And the air flows over the cylinders, 141 00:06:59,610 --> 00:07:01,980 but there's also a lot of oil circulating which has 142 00:07:01,980 --> 00:07:05,770 a significant cooling function. 143 00:07:05,770 --> 00:07:07,990 The lowest cost and simplest airplanes 144 00:07:07,990 --> 00:07:11,080 have a carburetor rather than fuel injection. 145 00:07:11,080 --> 00:07:15,100 And you'll get 200 horsepower or less out of a-- 146 00:07:15,100 --> 00:07:16,840 well, I guess the latest Lycoming's can 147 00:07:16,840 --> 00:07:20,080 do to 215 out of a 4-cylinder. 148 00:07:20,080 --> 00:07:22,290 You can get a little bit fancier. 149 00:07:22,290 --> 00:07:24,860 A plane like a Cirrus or the latest Cessnas 150 00:07:24,860 --> 00:07:26,920 will have fuel injection. 151 00:07:26,920 --> 00:07:29,960 Turbocharging sounds like the ideal thing for an aircraft. 152 00:07:29,960 --> 00:07:32,380 Why wouldn't you want that for a machine that 153 00:07:32,380 --> 00:07:35,500 goes through airs of all kinds of different densities? 154 00:07:35,500 --> 00:07:36,940 It seems like the ideal thing. 155 00:07:36,940 --> 00:07:39,250 Just make the density back to sea level at least 156 00:07:39,250 --> 00:07:42,550 all the time, which is called turbo-normalization. 157 00:07:42,550 --> 00:07:46,270 The problem is that they share an oil system 158 00:07:46,270 --> 00:07:49,150 with the rest of the engine, so when the turbocharger breaks, 159 00:07:49,150 --> 00:07:51,745 it tends to cause all of the oil to leak out of the engine. 160 00:07:51,745 --> 00:07:52,870 And now you have a broken-- 161 00:07:52,870 --> 00:07:55,090 you know, what had been a perfectly good engine 162 00:07:55,090 --> 00:07:59,440 with a broken turbocharger becomes a real emergency. 163 00:07:59,440 --> 00:08:02,170 So people's-- you know, except out west where you really need 164 00:08:02,170 --> 00:08:05,380 the performance because you are going up high a lot 165 00:08:05,380 --> 00:08:09,070 or you're starting from high and hot, 166 00:08:09,070 --> 00:08:11,452 the turbochargers tend to be unpopular, 167 00:08:11,452 --> 00:08:13,285 although it's an ideal engineering solution. 168 00:08:16,180 --> 00:08:18,500 The more cylinders also the less vibration, 169 00:08:18,500 --> 00:08:20,560 so if you have higher horsepower or if you just 170 00:08:20,560 --> 00:08:21,820 want it to be smooth. 171 00:08:21,820 --> 00:08:23,860 Like the original SR20s came with 172 00:08:23,860 --> 00:08:25,750 six-cylinder, 200-horsepower engines 173 00:08:25,750 --> 00:08:27,940 because they wanted it to be smoother. 174 00:08:30,720 --> 00:08:33,280 Rotax is the most popular engine in the light sport 175 00:08:33,280 --> 00:08:34,890 and experimental world. 176 00:08:34,890 --> 00:08:38,159 That's an engine that's a little bit more like a car engine. 177 00:08:38,159 --> 00:08:39,690 It revs pretty high. 178 00:08:39,690 --> 00:08:45,120 It's got a water-cooling radiator with antifreeze 179 00:08:45,120 --> 00:08:50,790 and the transmission gears that prop down to a lower speed. 180 00:08:50,790 --> 00:08:52,620 All right, here's your basic engine. 181 00:08:59,020 --> 00:09:02,140 So up here in the cylinder head, you 182 00:09:02,140 --> 00:09:05,950 have your intake, an exhaust valve, and your spark plug. 183 00:09:05,950 --> 00:09:09,880 Down here, there's the crankcase and crankshaft. 184 00:09:14,220 --> 00:09:17,530 Here's an exciting-- this is kind of an inline-four, 185 00:09:17,530 --> 00:09:21,408 but you get an idea of the power strokes. 186 00:09:21,408 --> 00:09:23,200 Everybody used to know this in the old days 187 00:09:23,200 --> 00:09:25,488 because they were excited about cars, 188 00:09:25,488 --> 00:09:27,280 so they had a lot of car-related knowledge, 189 00:09:27,280 --> 00:09:28,820 and it's basically the same idea. 190 00:09:28,820 --> 00:09:33,190 But now in the Uber age, we can't take that for granted. 191 00:09:33,190 --> 00:09:37,600 So you've got your intake stroke top left, 192 00:09:37,600 --> 00:09:40,550 and then the cylinder. 193 00:09:40,550 --> 00:09:45,910 The piston is pushed back up to compress the air-fuel mixture. 194 00:09:45,910 --> 00:09:47,440 The spark plugs ignite. 195 00:09:47,440 --> 00:09:50,140 Notice how there's two of them here. 196 00:09:50,140 --> 00:09:53,830 That gives you some redundancy as well as more uniformity 197 00:09:53,830 --> 00:09:58,390 of combustion, which pushes the piston back down generating 198 00:09:58,390 --> 00:09:59,290 the power. 199 00:09:59,290 --> 00:10:01,750 And then finally, the piston rotates up 200 00:10:01,750 --> 00:10:02,720 and pushes the air out. 201 00:10:02,720 --> 00:10:04,553 I think this might be called the Otto cycle. 202 00:10:04,553 --> 00:10:07,000 I think a German guy invented this-- 203 00:10:07,000 --> 00:10:10,060 or actually, a French guy patented it first, 204 00:10:10,060 --> 00:10:13,150 but maybe Otto reduced it to practice first. 205 00:10:13,150 --> 00:10:16,360 But anyway, it's a European invention from the late 1800s, 206 00:10:16,360 --> 00:10:19,180 and it really hasn't changed much-- 207 00:10:19,180 --> 00:10:20,690 four-stroke cycle. 208 00:10:20,690 --> 00:10:25,230 OK, cooling, as I said it's a combination of the air 209 00:10:25,230 --> 00:10:27,150 and the oil circulation. 210 00:10:27,150 --> 00:10:31,290 The FAA wants you to know that if you're getting the engine 211 00:10:31,290 --> 00:10:32,285 is going hot-- 212 00:10:32,285 --> 00:10:33,660 again, this is probably not going 213 00:10:33,660 --> 00:10:35,680 to happen to you here at level. 214 00:10:35,680 --> 00:10:39,810 But if you're climbing in your little airplane out of Wyoming 215 00:10:39,810 --> 00:10:41,970 on a hot day, you might end up having 216 00:10:41,970 --> 00:10:46,505 to accept a slightly lower climb rate, 217 00:10:46,505 --> 00:10:47,880 boost your airspeed a little bit, 218 00:10:47,880 --> 00:10:51,660 and lower the nose to get more cooling air. 219 00:10:51,660 --> 00:10:54,150 The mixture control, you don't see this in cars 220 00:10:54,150 --> 00:10:55,770 because they have automatic systems 221 00:10:55,770 --> 00:10:59,760 to adjust the air-fuel mixture and get 222 00:10:59,760 --> 00:11:01,920 the right amount of fuel in there corresponding 223 00:11:01,920 --> 00:11:06,060 to the density of the air. 224 00:11:06,060 --> 00:11:09,450 But in aviation, you know there's your little mixture 225 00:11:09,450 --> 00:11:12,060 knob where you can lean out the mixture. 226 00:11:16,220 --> 00:11:18,730 The fuel-air mixture, you start out 227 00:11:18,730 --> 00:11:21,040 rich when you're taking off because you're 228 00:11:21,040 --> 00:11:23,980 at a very high power setting, and the extra rich mixture 229 00:11:23,980 --> 00:11:26,680 cools the engine. 230 00:11:26,680 --> 00:11:28,930 If you go really extreme with this, 231 00:11:28,930 --> 00:11:31,780 like you just taxi around for half an hour 232 00:11:31,780 --> 00:11:34,720 with the mixture control at full rich, in some engines 233 00:11:34,720 --> 00:11:37,060 you may end up getting lead fouling on the spark plugs. 234 00:11:40,600 --> 00:11:44,740 If you're up cruising and you lean it out too much 235 00:11:44,740 --> 00:11:47,170 then the engine's going to get a little bit rough, 236 00:11:47,170 --> 00:11:50,170 and some of the temperatures will go too high. 237 00:11:50,170 --> 00:11:53,860 On the modern aircraft, you have very sophisticated engine 238 00:11:53,860 --> 00:11:57,345 monitors that tell you all kinds of information about what 239 00:11:57,345 --> 00:11:58,220 the temperatures are. 240 00:11:58,220 --> 00:12:02,530 They may help you lean to the optimum mixture. 241 00:12:02,530 --> 00:12:05,905 If you have an autopilot, it's kind of a good way 242 00:12:05,905 --> 00:12:08,155 to invest some of your time once you're in the cruise. 243 00:12:11,050 --> 00:12:13,630 Carburetors, how do they work? 244 00:12:13,630 --> 00:12:17,290 If you fly a Piper or a Cessna you can say that you have 245 00:12:17,290 --> 00:12:20,940 a jet-powered aircraft because there is a jet 246 00:12:20,940 --> 00:12:25,590 in the carburetor that's letting the low-pressure air and this 247 00:12:25,590 --> 00:12:31,062 venturi pull little bits of fuel vapor out into the-- 248 00:12:31,062 --> 00:12:33,270 well, I guess that throttle looks pretty well closed, 249 00:12:33,270 --> 00:12:36,150 but ideally the throttle would be kind of open, 250 00:12:36,150 --> 00:12:41,638 and the air-fuel mixture would be going into the cylinders. 251 00:12:45,940 --> 00:12:51,380 Carb icing, so remember, lower pressure-- 252 00:12:51,380 --> 00:12:54,800 as the pressure falls the temperature will also fall. 253 00:12:54,800 --> 00:12:57,560 So even if it's not below freezing outside 254 00:12:57,560 --> 00:13:01,040 it can become below freezing in the middle of the carburetor, 255 00:13:01,040 --> 00:13:05,120 and, therefore, water vapor that has been in the air 256 00:13:05,120 --> 00:13:09,920 can turn into ice and eventually block the airflow 257 00:13:09,920 --> 00:13:12,530 to the engine. 258 00:13:12,530 --> 00:13:14,300 So they tell you, look, well, just 259 00:13:14,300 --> 00:13:16,010 detect that by loss of RPM. 260 00:13:16,010 --> 00:13:17,550 You know, you're flying along. 261 00:13:17,550 --> 00:13:19,622 You should be watching the RPM gauge. 262 00:13:19,622 --> 00:13:21,080 So obviously, you would notice this 263 00:13:21,080 --> 00:13:23,367 and take the correct action, instead 264 00:13:23,367 --> 00:13:25,700 of having a machine that would figure this out and do it 265 00:13:25,700 --> 00:13:27,580 for you. 266 00:13:27,580 --> 00:13:29,330 I guess one reason they don't want to just 267 00:13:29,330 --> 00:13:31,310 have carb heat on all the time is 268 00:13:31,310 --> 00:13:39,230 that it robs the engine of some of its last 10 or 15 horsepower 269 00:13:39,230 --> 00:13:40,100 or whatever. 270 00:13:40,100 --> 00:13:44,030 So the carb heat because it makes the air hotter, 271 00:13:44,030 --> 00:13:48,020 it's just like going up to a higher altitude 272 00:13:48,020 --> 00:13:49,442 or flying on a hotter day. 273 00:13:49,442 --> 00:13:51,650 The air is going to be thinner, and, therefore, there 274 00:13:51,650 --> 00:13:54,557 are fewer molecules of air to combust, 275 00:13:54,557 --> 00:13:55,890 and you won't get as much power. 276 00:13:55,890 --> 00:13:56,390 Question. 277 00:13:56,390 --> 00:13:59,802 AUDIENCE: What generates the carb heat of the engine? 278 00:13:59,802 --> 00:14:01,760 PHILIP GREENSPUN: What generates the carb heat? 279 00:14:01,760 --> 00:14:02,752 That's a good question. 280 00:14:02,752 --> 00:14:04,460 Same thing that generates the cabin heat. 281 00:14:04,460 --> 00:14:07,685 You basically run the air over the exhaust system 282 00:14:07,685 --> 00:14:09,560 before it goes to the carburetor or before it 283 00:14:09,560 --> 00:14:11,300 comes into the cabin. 284 00:14:11,300 --> 00:14:13,880 Good question. 285 00:14:13,880 --> 00:14:16,250 Yes, so I think 1950s cars had some kind 286 00:14:16,250 --> 00:14:18,010 of automatic mechanism for this-- 287 00:14:18,010 --> 00:14:22,320 it was, you know, buy a metal valve, and I don't know. 288 00:14:22,320 --> 00:14:25,070 The mixture control hasn't been seen in automobiles 289 00:14:25,070 --> 00:14:26,480 for quite a long time. 290 00:14:26,480 --> 00:14:28,430 The ignition systems of aircraft is actually 291 00:14:28,430 --> 00:14:29,900 pretty well designed. 292 00:14:29,900 --> 00:14:32,330 You have magnetos. 293 00:14:32,330 --> 00:14:35,540 You can see them here and here. 294 00:14:35,540 --> 00:14:37,200 You can see him here at the bottom. 295 00:14:37,200 --> 00:14:40,310 The left and right magnetos are geared into the engine, 296 00:14:40,310 --> 00:14:44,690 and they generate their own voltage. 297 00:14:44,690 --> 00:14:47,780 So basically, you don't need to have a working battery 298 00:14:47,780 --> 00:14:52,430 or working alternator to have a running engine unlike in a car. 299 00:14:52,430 --> 00:14:54,290 All you need is these. 300 00:14:54,290 --> 00:14:58,110 One of the magnetos is still connected and working properly. 301 00:14:58,110 --> 00:14:59,720 So it's totally separate from what 302 00:14:59,720 --> 00:15:04,640 you might think of as the aircraft's electrical system. 303 00:15:04,640 --> 00:15:08,780 And for further redundancy, each magneto 304 00:15:08,780 --> 00:15:12,380 is connected to half of the spark plugs 305 00:15:12,380 --> 00:15:15,530 such that if you lose a magneto, you still 306 00:15:15,530 --> 00:15:20,450 have one working spark plug in each cylinder. 307 00:15:20,450 --> 00:15:22,140 Does that make sense? 308 00:15:22,140 --> 00:15:24,740 You can see that in this drawing here where 309 00:15:24,740 --> 00:15:26,780 each cylinder is being fed either from the green 310 00:15:26,780 --> 00:15:30,110 or the blue magneto to one of the two spark plugs. 311 00:15:30,110 --> 00:15:32,270 And you can test to see if it runs smoothly 312 00:15:32,270 --> 00:15:34,330 on either magneto. 313 00:15:34,330 --> 00:15:36,050 Your ignition switch on the airplane 314 00:15:36,050 --> 00:15:39,890 will have a right mag only switch, a left mag only switch, 315 00:15:39,890 --> 00:15:42,830 or both mags, which is where you have normal operation. 316 00:15:42,830 --> 00:15:44,810 But when you're testing on the ground 317 00:15:44,810 --> 00:15:48,560 you'll typically see if it works on either magneto. 318 00:15:48,560 --> 00:15:51,710 OK, abnormal combustion, what can you get? 319 00:15:51,710 --> 00:15:59,680 You can get detonation which is the mixture ignites 320 00:15:59,680 --> 00:16:05,200 before the spark ignites. 321 00:16:05,200 --> 00:16:11,870 Or pre-ignition, which is the slow burn before the spark. 322 00:16:11,870 --> 00:16:14,980 And detonation I think is probably 323 00:16:14,980 --> 00:16:17,240 the one that's more common. 324 00:16:17,240 --> 00:16:21,650 And it could be caused by improper leaning. 325 00:16:24,680 --> 00:16:28,658 Aviation fuel, basically 100 low led 326 00:16:28,658 --> 00:16:30,450 which is dyed blue is all that you're going 327 00:16:30,450 --> 00:16:34,960 to see in the continental US. 328 00:16:34,960 --> 00:16:37,150 In the future though-- 329 00:16:37,150 --> 00:16:39,730 so low that means it's lower in less than the stuff 330 00:16:39,730 --> 00:16:43,670 that they were making in the 1930s or whatever. 331 00:16:43,670 --> 00:16:44,920 It's still pretty high in led. 332 00:16:44,920 --> 00:16:46,870 It's like the super-- 333 00:16:46,870 --> 00:16:48,520 it's like the premium leaded gasoline, 334 00:16:48,520 --> 00:16:51,560 I think, of the 1970s. 335 00:16:51,560 --> 00:16:54,070 Most engines actually don't require this. 336 00:16:54,070 --> 00:16:58,210 It's just that it takes so long to get anything done 337 00:16:58,210 --> 00:17:01,990 in aviation that they can't put an alternative certify and get 338 00:17:01,990 --> 00:17:05,170 an alternative fuel to the airports. 339 00:17:05,170 --> 00:17:09,130 But, you know, your typical Cessna or your Robinson R44 340 00:17:09,130 --> 00:17:11,740 with the carburetor, it doesn't need 341 00:17:11,740 --> 00:17:14,950 this lead that's in the fuel and then 342 00:17:14,950 --> 00:17:17,359 gets spewed out in the atmosphere. 343 00:17:17,359 --> 00:17:18,740 It's kind of a tragedy. 344 00:17:18,740 --> 00:17:21,490 And it's been made worse by this ethanol stuff. 345 00:17:21,490 --> 00:17:24,760 So the government says you have to put ethanol in car gasoline. 346 00:17:24,760 --> 00:17:27,700 So you can't just go and take premium car gas 347 00:17:27,700 --> 00:17:30,520 from the gas station and pour it into your aircraft 348 00:17:30,520 --> 00:17:31,970 from a technical point of view-- 349 00:17:31,970 --> 00:17:34,300 even if it were legal regulatory-wise-- 350 00:17:34,300 --> 00:17:37,390 because the ethanol will destroy a lot of the fuel system 351 00:17:37,390 --> 00:17:39,740 in the aircraft which wasn't engineered for it. 352 00:17:39,740 --> 00:17:41,960 But if you did have ethanol-free-- 353 00:17:41,960 --> 00:17:44,020 there are a few places that have mogas. 354 00:17:44,020 --> 00:17:46,690 They get special ethanol-free car gas, 355 00:17:46,690 --> 00:17:49,930 and lower-performance aircraft engines 356 00:17:49,930 --> 00:17:51,520 will run just fine on them. 357 00:17:51,520 --> 00:17:53,220 There have been committees-- you know 358 00:17:53,220 --> 00:17:55,840 20 years is kind of like the standard unit of time 359 00:17:55,840 --> 00:17:56,530 in aviation. 360 00:17:56,530 --> 00:17:58,360 So for about 20 years, people have 361 00:17:58,360 --> 00:18:01,420 been working on some kind of certified unleaded gasoline 362 00:18:01,420 --> 00:18:03,610 that will work with most engines. 363 00:18:03,610 --> 00:18:08,290 If you see clear fuel in the sump, 364 00:18:08,290 --> 00:18:10,870 it usually means the airplane's been left out in the rain, 365 00:18:10,870 --> 00:18:12,820 and some water has gotten in there. 366 00:18:12,820 --> 00:18:15,340 And you got to make sure that you drain that out. 367 00:18:15,340 --> 00:18:19,040 So there's drain plugs on the bottom of the wings typically, 368 00:18:19,040 --> 00:18:21,620 and maybe one near the bottom of the engine 369 00:18:21,620 --> 00:18:23,020 that you can see if any water has 370 00:18:23,020 --> 00:18:24,910 gotten into the fuel system. 371 00:18:24,910 --> 00:18:29,890 Jet fuel is hazardous to piston engines. 372 00:18:29,890 --> 00:18:31,960 The nozzles are designed so that they're 373 00:18:31,960 --> 00:18:33,410 physically incompatible. 374 00:18:33,410 --> 00:18:36,700 You shouldn't be able to put jet fuel into a piston engine. 375 00:18:36,700 --> 00:18:38,308 Occasionally it does happen. 376 00:18:38,308 --> 00:18:39,850 I know a guy who was flying his Piper 377 00:18:39,850 --> 00:18:42,190 Malibu all around the world, and he 378 00:18:42,190 --> 00:18:45,940 got some barrels of fuel delivered to him, 379 00:18:45,940 --> 00:18:47,350 and he had to pump it himself. 380 00:18:47,350 --> 00:18:49,963 And I don't know, for whatever reason, 381 00:18:49,963 --> 00:18:51,130 there was jet fuel in there. 382 00:18:51,130 --> 00:18:52,621 AUDIENCE: So Philip, you might want 383 00:18:52,621 --> 00:18:53,840 to kind of stop [INAUDIBLE]. 384 00:18:53,840 --> 00:18:55,340 PHILIP GREENSPUN: Is the pizza here? 385 00:18:55,340 --> 00:18:57,132 AUDIENCE: No, not yet, but it's noon. 386 00:18:57,132 --> 00:18:59,507 PHILIP GREENSPUN: Yeah, well, whenever the pizza is here. 387 00:19:02,350 --> 00:19:06,070 I think we're-- yeah, we'll take a break as soon as the pizza 388 00:19:06,070 --> 00:19:07,180 shows up. 389 00:19:07,180 --> 00:19:10,840 All right, fixed-pitch propellers. 390 00:19:10,840 --> 00:19:15,700 So your most basic trainer has a regular propeller 391 00:19:15,700 --> 00:19:21,220 that its angle relative to the hub never changes. 392 00:19:21,220 --> 00:19:24,310 There's also in higher-performance aircraft, 393 00:19:24,310 --> 00:19:28,810 constant-speed propellers where there's an adjustment mechanism 394 00:19:28,810 --> 00:19:30,460 that you can read about-- 395 00:19:30,460 --> 00:19:33,880 a mechanical collection of springs 396 00:19:33,880 --> 00:19:36,070 and spinning weights that will try 397 00:19:36,070 --> 00:19:39,940 to keep the propeller at 1RPM, and that 398 00:19:39,940 --> 00:19:42,910 can be a lot more efficient in different phases of flight. 399 00:19:42,910 --> 00:19:44,890 You can see from this that if you 400 00:19:44,890 --> 00:19:48,190 have a constant-speed propeller, the efficiency 401 00:19:48,190 --> 00:19:51,910 across a huge range of speeds is roughly constant, 402 00:19:51,910 --> 00:19:56,080 whereas if you have a climb prop or a cruise 403 00:19:56,080 --> 00:20:02,680 prop it's only working optimally at certain airspeeds. 404 00:20:02,680 --> 00:20:05,860 All right, so if you have a constant-speed propeller 405 00:20:05,860 --> 00:20:07,750 you're now going to have free power levers. 406 00:20:07,750 --> 00:20:10,210 That's the business end of it and from a pilot's point 407 00:20:10,210 --> 00:20:10,960 of view. 408 00:20:10,960 --> 00:20:14,500 You'll have throttle which is the black one 409 00:20:14,500 --> 00:20:22,800 on the left, the blue prop-speed control, and then 410 00:20:22,800 --> 00:20:24,870 the red mixture. 411 00:20:24,870 --> 00:20:27,210 The FAA, they may ask you about this. 412 00:20:27,210 --> 00:20:28,680 You know they have this doctrine. 413 00:20:28,680 --> 00:20:30,180 It's not really true of all engines, 414 00:20:30,180 --> 00:20:33,330 but the idea is that you don't want like a high power setting 415 00:20:33,330 --> 00:20:35,270 and a really low RPM setting. 416 00:20:35,270 --> 00:20:37,680 They claim that that's making the propeller take 417 00:20:37,680 --> 00:20:41,250 such big bites of the air to keep the low speed that it's 418 00:20:41,250 --> 00:20:43,770 somehow stressing the engine. 419 00:20:43,770 --> 00:20:47,580 But, again, not every engine manufacturer agrees with that. 420 00:20:47,580 --> 00:20:49,380 All right, let's talk about-- 421 00:20:49,380 --> 00:20:51,400 we'll start in on flight instruments 422 00:20:51,400 --> 00:20:54,000 until our pizza arrives. 423 00:20:54,000 --> 00:20:59,370 So this is going to be your reality I would say. 424 00:20:59,370 --> 00:21:05,310 Some of the test stuff concerns the steam gauges of the past 425 00:21:05,310 --> 00:21:06,960 that you still see at flight schools. 426 00:21:06,960 --> 00:21:11,175 And that there are some things that we can learn from this 427 00:21:11,175 --> 00:21:12,300 though that we'll get into. 428 00:21:12,300 --> 00:21:14,040 There are some advantages. 429 00:21:14,040 --> 00:21:16,410 But anyway, let's start with this six-pack 430 00:21:16,410 --> 00:21:18,900 because actually, the electronic stuff 431 00:21:18,900 --> 00:21:21,000 is mostly trying to replicate what 432 00:21:21,000 --> 00:21:24,015 was done during World War II. 433 00:21:24,015 --> 00:21:25,890 There's very little in a modern aircraft that 434 00:21:25,890 --> 00:21:28,710 isn't some kind of upgraded version of what was in a Boeing 435 00:21:28,710 --> 00:21:33,520 B29 bomber, so it's worth kind of knowing where it came from. 436 00:21:33,520 --> 00:21:34,690 So you've got your six-pack. 437 00:21:34,690 --> 00:21:37,890 You've got your airspeed indicator. 438 00:21:37,890 --> 00:21:40,200 On the top left, you've got your attitude indicator 439 00:21:40,200 --> 00:21:42,300 or artificial horizon. 440 00:21:42,300 --> 00:21:45,150 You've got your altimeter on the top right, 441 00:21:45,150 --> 00:21:46,800 vertical speed coming down around 442 00:21:46,800 --> 00:21:50,190 to the lower right, which tells you how fast you're going up 443 00:21:50,190 --> 00:21:55,170 or how fast you're going down, a directional gyro which 444 00:21:55,170 --> 00:21:58,350 is like a stabilized compass showing you 445 00:21:58,350 --> 00:22:01,750 where you're pointed assuming it's been adjusted properly. 446 00:22:01,750 --> 00:22:04,230 It has to be reset to the compass in flight 447 00:22:04,230 --> 00:22:05,316 every now and then. 448 00:22:05,316 --> 00:22:07,542 Ah-ha, is our pizza here? 449 00:22:07,542 --> 00:22:08,750 AUDIENCE: I wish I had pizza. 450 00:22:08,750 --> 00:22:09,480 PHILIP GREENSPUN: You didn't see any? 451 00:22:09,480 --> 00:22:10,170 AUDIENCE: No. 452 00:22:10,170 --> 00:22:11,212 PHILIP GREENSPUN: Oh, no. 453 00:22:13,530 --> 00:22:20,460 OK, and then you have a turn coordinator 454 00:22:20,460 --> 00:22:22,890 which is another backup gyro that tells you 455 00:22:22,890 --> 00:22:27,090 whether you're turning left or right and also 456 00:22:27,090 --> 00:22:27,810 the coordination. 457 00:22:27,810 --> 00:22:28,470 That's just a ball. 458 00:22:28,470 --> 00:22:30,012 We'll get into that in a little bit-- 459 00:22:30,012 --> 00:22:35,010 about whether the airplane is kind of pitched-- 460 00:22:35,010 --> 00:22:37,500 improperly yawed. 461 00:22:37,500 --> 00:22:41,480 All right, so it says electric. 462 00:22:41,480 --> 00:22:43,818 For a gyroscope to keep spinning that means 463 00:22:43,818 --> 00:22:45,110 it's being powered by electric. 464 00:22:45,110 --> 00:22:46,485 What else could it be powered by? 465 00:22:46,485 --> 00:22:47,875 Does anybody know? 466 00:22:47,875 --> 00:22:49,760 What else is there besides electricity 467 00:22:49,760 --> 00:22:52,222 that can make this thing spin? 468 00:22:52,222 --> 00:22:53,014 AUDIENCE: A vacuum. 469 00:22:53,014 --> 00:22:54,389 PHILIP GREENSPUN: Yeah, a vacuum. 470 00:22:54,389 --> 00:22:56,320 So in the old days-- you know, again, this 471 00:22:56,320 --> 00:22:58,903 is not as common-- you'd have a vacuum pump on the engine that 472 00:22:58,903 --> 00:23:05,980 would generate a force to keep these gyros spinning. 473 00:23:05,980 --> 00:23:08,893 And those were often failing which had some pretty bad-- 474 00:23:08,893 --> 00:23:10,643 AUDIENCE: So these are the current reality 475 00:23:10,643 --> 00:23:12,190 of many of our planes? 476 00:23:12,190 --> 00:23:13,600 PHILIP GREENSPUN: I don't know of how many-- yeah, I guess 477 00:23:13,600 --> 00:23:14,813 there's a few Piper Warriors. 478 00:23:14,813 --> 00:23:17,230 Yeah, that's a good reason not to take like the most basic 479 00:23:17,230 --> 00:23:18,272 airplane into the clouds. 480 00:23:18,272 --> 00:23:21,883 Because the idea is that you're supposed to sort of notice. 481 00:23:21,883 --> 00:23:23,050 Do they have-- I don't know. 482 00:23:23,050 --> 00:23:24,760 I guess some of them have a little warning light when 483 00:23:24,760 --> 00:23:25,960 the vacuum pump fails. 484 00:23:25,960 --> 00:23:29,380 But in the most classic situation, 485 00:23:29,380 --> 00:23:32,410 you're supposed to notice as the pilot in the clouds 486 00:23:32,410 --> 00:23:34,300 that this artificial horizon is failing 487 00:23:34,300 --> 00:23:37,430 and it's inconsistent with this instrument. 488 00:23:37,430 --> 00:23:40,180 And then you decide which of the two to believe. 489 00:23:40,180 --> 00:23:42,910 Generally, it's this one because it's more viable. 490 00:23:42,910 --> 00:23:44,950 And then you continue your flight to the cloud 491 00:23:44,950 --> 00:23:47,030 without the artificial horizon. 492 00:23:47,030 --> 00:23:49,420 Anyway, that's ridiculous obviously. 493 00:23:49,420 --> 00:23:52,900 So, you know the real IFR airplanes these days 494 00:23:52,900 --> 00:23:57,420 have two attitude indicators, both powered by electric. 495 00:23:57,420 --> 00:23:59,920 And you don't have to sort of notice the subtle sign of them 496 00:23:59,920 --> 00:24:00,700 failing. 497 00:24:00,700 --> 00:24:03,670 There's just a big flag that pops up when they fail-- 498 00:24:03,670 --> 00:24:06,445 you know, if they lose power for some reason, for example. 499 00:24:09,440 --> 00:24:12,100 All right, the pitot-static system. 500 00:24:12,100 --> 00:24:15,460 So how do you know anything about your airspeed? 501 00:24:15,460 --> 00:24:18,780 There's a tube somewhere on the airplane usually hanging out 502 00:24:18,780 --> 00:24:22,420 under the wing in your typical trainer or next to the nose. 503 00:24:22,420 --> 00:24:27,090 You see them on jets where the ram air comes in, 504 00:24:27,090 --> 00:24:30,290 and the more ram air pressure there is, then 505 00:24:30,290 --> 00:24:32,070 the faster you're going. 506 00:24:32,070 --> 00:24:36,470 That can be compared to the static pressure which 507 00:24:36,470 --> 00:24:39,413 comes in from a static port usually 508 00:24:39,413 --> 00:24:40,580 on the side of the airplane. 509 00:24:40,580 --> 00:24:43,130 It has to be in some part of the airplane 510 00:24:43,130 --> 00:24:48,050 where the airflow is suitable for a static port. 511 00:24:48,050 --> 00:24:51,510 So the ram air feeds only the airspeed indicator, 512 00:24:51,510 --> 00:24:54,800 and the static source has to feed the altimeter 513 00:24:54,800 --> 00:24:56,720 and the vertical speed. 514 00:24:56,720 --> 00:24:58,160 You've got to read this book. 515 00:24:58,160 --> 00:24:59,827 There's a couple of questions about what 516 00:24:59,827 --> 00:25:02,450 happens if the pitot tube gets clogged 517 00:25:02,450 --> 00:25:05,140 or if the static port is blocked and taped over, 518 00:25:05,140 --> 00:25:07,830 and that makes the instruments read inaccurately. 519 00:25:07,830 --> 00:25:10,980 So I'd read about that for the test. 520 00:25:10,980 --> 00:25:12,720 OK, airspeed indicator, here's what 521 00:25:12,720 --> 00:25:16,980 I was talking about how in some ways the old stuff is better. 522 00:25:16,980 --> 00:25:22,505 So, look, here's a good example of how you get more information 523 00:25:22,505 --> 00:25:23,880 out of this than out of the speed 524 00:25:23,880 --> 00:25:25,130 tape on the modern instrument. 525 00:25:25,130 --> 00:25:27,880 This gives you all of the aircraft's performance 526 00:25:27,880 --> 00:25:28,380 basically. 527 00:25:28,380 --> 00:25:31,230 You don't really need to refer to the manual 528 00:25:31,230 --> 00:25:33,420 to see a lot of important information. 529 00:25:33,420 --> 00:25:37,470 Well, don't fly-- you know, the speed tape might only show you 530 00:25:37,470 --> 00:25:39,990 from here to here-- 531 00:25:39,990 --> 00:25:44,530 from like 120 knots up to 150 or something. 532 00:25:44,530 --> 00:25:46,710 But here you're seeing, OK, let's not fly faster 533 00:25:46,710 --> 00:25:49,620 than about 208 knots. 534 00:25:49,620 --> 00:25:51,840 Unless we have the flaps out, let's not 535 00:25:51,840 --> 00:25:54,930 fly slower than about 58 knots. 536 00:25:54,930 --> 00:25:58,500 And even with the flaps hanging down, 537 00:25:58,500 --> 00:26:01,008 we don't want to fly slower than 55 knots 538 00:26:01,008 --> 00:26:02,550 because that's going to be where it's 539 00:26:02,550 --> 00:26:05,760 going to stall at certain CG configurations 540 00:26:05,760 --> 00:26:07,110 and at gross weight. 541 00:26:07,110 --> 00:26:08,250 OK, the yellow arc. 542 00:26:08,250 --> 00:26:11,100 Well, the yellow arc is to be avoided 543 00:26:11,100 --> 00:26:13,380 unless the air is smooth. 544 00:26:13,380 --> 00:26:16,410 So that was actually a great user interface. 545 00:26:16,410 --> 00:26:19,710 And because cool jets have the speed tape 546 00:26:19,710 --> 00:26:23,677 when they make the glass panels for little airplanes 547 00:26:23,677 --> 00:26:26,010 which really don't need that kind of precision and speed 548 00:26:26,010 --> 00:26:28,350 control, they said, well, let's just 549 00:26:28,350 --> 00:26:31,800 have this thing that the jet pilots have. 550 00:26:31,800 --> 00:26:34,910 All right, how does the airspeed indicator work? 551 00:26:34,910 --> 00:26:39,810 There's brass in there, so it's a cool old-school Sherlock 552 00:26:39,810 --> 00:26:42,040 Holmes-style brass instrument. 553 00:26:42,040 --> 00:26:45,180 The ram air is coming in. 554 00:26:45,180 --> 00:26:49,410 There's a diaphragm that moves some levers, and eventually 555 00:26:49,410 --> 00:26:51,370 the needle swings. 556 00:26:51,370 --> 00:26:54,555 Again, you know, you don't have to design one for your test. 557 00:26:54,555 --> 00:26:57,000 You just have to know that it's going 558 00:26:57,000 --> 00:26:58,140 to respond to the ram air. 559 00:27:01,140 --> 00:27:04,920 Some of these little symbols are worth knowing. 560 00:27:04,920 --> 00:27:08,520 Probably Va is the most important 561 00:27:08,520 --> 00:27:10,313 because it's on the test, I believe, 562 00:27:10,313 --> 00:27:11,730 as something that is not indicated 563 00:27:11,730 --> 00:27:13,080 on the airspeed indicator. 564 00:27:13,080 --> 00:27:14,580 That's the maneuvering speed. 565 00:27:14,580 --> 00:27:19,110 That's the speed at which you can do extreme control inputs 566 00:27:19,110 --> 00:27:20,610 and not bend the airplane. 567 00:27:20,610 --> 00:27:22,940 Any faster than maneuvering speed 568 00:27:22,940 --> 00:27:25,830 it's possible that you could yank the yoke back so 569 00:27:25,830 --> 00:27:29,790 hard that you'd bend the wings a little bit or overstress them. 570 00:27:29,790 --> 00:27:32,460 The reason it's not indicated on the airspeed indicator 571 00:27:32,460 --> 00:27:34,480 is it varies by weight. 572 00:27:34,480 --> 00:27:35,700 And it's actually higher-- 573 00:27:35,700 --> 00:27:37,510 that's something worth reading about-- 574 00:27:37,510 --> 00:27:39,180 it's higher if the airplane is heavier. 575 00:27:39,180 --> 00:27:43,260 It's one of the few speeds where weight is helpful 576 00:27:43,260 --> 00:27:45,090 because if it's really heavy, it's 577 00:27:45,090 --> 00:27:48,030 just harder to get the airplane to perform 578 00:27:48,030 --> 00:27:52,050 in some extreme manner. 579 00:27:52,050 --> 00:27:53,750 VSO is also worth looking at. 580 00:27:53,750 --> 00:27:56,250 That's basically the speed that's 581 00:27:56,250 --> 00:27:57,960 going to determine how fast you land. 582 00:27:57,960 --> 00:28:00,000 That's the speed that the airplane will 583 00:28:00,000 --> 00:28:01,800 stall on landing configuration. 584 00:28:01,800 --> 00:28:03,700 So you usually want to be going at least 20% 585 00:28:03,700 --> 00:28:08,080 faster than that to give yourself a safety margin. 586 00:28:08,080 --> 00:28:10,360 OK, here's something from the New England Air Museum 587 00:28:10,360 --> 00:28:12,510 in Bradley, Connecticut-- another great destination 588 00:28:12,510 --> 00:28:15,610 about half an hour's flight away, huge airport, great FBO. 589 00:28:15,610 --> 00:28:18,240 They will give you a free car to use while you're there. 590 00:28:18,240 --> 00:28:20,400 It's called Signature Flight Support there. 591 00:28:20,400 --> 00:28:23,050 Anyway, so this aircraft-- 592 00:28:23,050 --> 00:28:25,300 I think it's a P40 from World War II, 593 00:28:25,300 --> 00:28:29,230 and it can go up to 500 miles an hour. 594 00:28:29,230 --> 00:28:33,580 All right, altimeter, this aircraft 595 00:28:33,580 --> 00:28:35,750 is at about 10,000 feet. 596 00:28:35,750 --> 00:28:41,370 So notice it has this little triangular 597 00:28:41,370 --> 00:28:45,090 needle at 1 that's telling you that it's at 10,000 feet. 598 00:28:45,090 --> 00:28:50,490 And then the longer needle is reading in hundreds, 599 00:28:50,490 --> 00:28:53,190 so we're at about 10,200. 600 00:28:53,190 --> 00:28:55,470 And sure enough, we can see this is indicating 601 00:28:55,470 --> 00:29:00,000 you know 10,180, so 3 needles. 602 00:29:00,000 --> 00:29:02,100 Usually, the ones you're going to deal with 603 00:29:02,100 --> 00:29:08,840 are this one at the top here for thousands of feet 604 00:29:08,840 --> 00:29:12,710 and this one for hundreds of feet. 605 00:29:12,710 --> 00:29:15,070 OK, so back in the old days before we 606 00:29:15,070 --> 00:29:20,020 decided to dig up all the coal and the oil and set it on fire, 607 00:29:20,020 --> 00:29:21,730 this was our standard atmosphere, 608 00:29:21,730 --> 00:29:23,200 and it was wonderful. 609 00:29:23,200 --> 00:29:26,020 And it was always 15 degrees at sea level. 610 00:29:26,020 --> 00:29:28,420 And it was always 29 or niner two for pressure, 611 00:29:28,420 --> 00:29:30,980 but now we've ruined it. 612 00:29:30,980 --> 00:29:33,280 The standard atmosphere is the basis 613 00:29:33,280 --> 00:29:37,060 for a huge number of calculations. 614 00:29:37,060 --> 00:29:41,590 The altimeter, we're going to look at this again. 615 00:29:41,590 --> 00:29:46,810 It has these android wafers that, I guess, 616 00:29:46,810 --> 00:29:49,840 provide a reference pressure. 617 00:29:49,840 --> 00:29:52,570 And somehow the difference between what's in there 618 00:29:52,570 --> 00:29:55,360 and what's coming in will make the needles move. 619 00:29:55,360 --> 00:29:57,370 That's about as much as I know not 620 00:29:57,370 --> 00:30:01,100 being a mechanical engineer. 621 00:30:01,100 --> 00:30:03,380 An important factor though with all these altimeters 622 00:30:03,380 --> 00:30:06,770 is you can set it to correct it for whatever the prevailing 623 00:30:06,770 --> 00:30:07,790 pressure is locally. 624 00:30:07,790 --> 00:30:09,915 So that's what you really need to know as a pilot-- 625 00:30:09,915 --> 00:30:11,930 that if they tell you the altimeter setting 626 00:30:11,930 --> 00:30:19,410 is 3053, that you turn it until you see 3053 in the window. 627 00:30:19,410 --> 00:30:21,620 It's worth knowing these altitude definitions. 628 00:30:21,620 --> 00:30:26,000 The most important for determining aircraft 629 00:30:26,000 --> 00:30:28,460 performance is going to be density altitude. 630 00:30:28,460 --> 00:30:31,250 That kind of tracks the actual number 631 00:30:31,250 --> 00:30:35,570 of molecules that are in a given volume of air. 632 00:30:35,570 --> 00:30:37,940 If you're flying along, you'll be 633 00:30:37,940 --> 00:30:39,620 looking at indicated altitude. 634 00:30:39,620 --> 00:30:44,030 That's kind of how aircraft tend to be separated. 635 00:30:44,030 --> 00:30:46,040 Everything else is kind of nice to know. 636 00:30:46,040 --> 00:30:48,570 Pressure altitude, we talk about it a lot, 637 00:30:48,570 --> 00:30:50,870 but I don't think it's really often used 638 00:30:50,870 --> 00:30:53,312 in practice for much. 639 00:30:53,312 --> 00:30:54,770 Actually above it-- I shouldn't say 640 00:30:54,770 --> 00:30:58,040 that because above 18,000 feet it's used. 641 00:30:58,040 --> 00:31:02,222 You always set the altimeter to flight level-- 642 00:31:02,222 --> 00:31:06,735 you know, 220 instead of 22,000 feet. 643 00:31:06,735 --> 00:31:09,110 If the temperature standard pressure altitude and density 644 00:31:09,110 --> 00:31:11,580 altitude are going to be the same-- 645 00:31:11,580 --> 00:31:14,360 so that would be, again, 15 degrees at sea level and cooler 646 00:31:14,360 --> 00:31:14,990 as you go up-- 647 00:31:17,760 --> 00:31:21,850 the pressure altitude will also equal the true altitude. 648 00:31:21,850 --> 00:31:24,480 So that's the actual height above sea level, 649 00:31:24,480 --> 00:31:26,710 again, in standard atmospheric conditions. 650 00:31:26,710 --> 00:31:29,560 We'll talk about this at a few times in this class. 651 00:31:29,560 --> 00:31:33,270 But when it's hot the entire Earth's atmosphere expands, 652 00:31:33,270 --> 00:31:36,630 and if we were to cool the earth down near absolute zero, 653 00:31:36,630 --> 00:31:38,700 the atmosphere would contract. 654 00:31:38,700 --> 00:31:41,880 We might read on our altimeter that we were at 18,000 feet 655 00:31:41,880 --> 00:31:43,770 when we were only, you know, an inch 656 00:31:43,770 --> 00:31:47,250 above the ground because the Earth's atmosphere had shrunk 657 00:31:47,250 --> 00:31:50,820 to only two inches in size. 658 00:31:50,820 --> 00:31:56,820 All right, when you're flying indicated altitude there's 659 00:31:56,820 --> 00:32:00,030 an expression called "high to low, look out below." 660 00:32:00,030 --> 00:32:02,160 Because if you go from an area where 661 00:32:02,160 --> 00:32:05,580 there's a high-pressure setting to an area where there's 662 00:32:05,580 --> 00:32:08,730 a low-pressure setting, you'll inadvertently 663 00:32:08,730 --> 00:32:11,520 descend by 1,000 feet if you just 664 00:32:11,520 --> 00:32:16,350 follow what the altimeter is telling you without resetting 665 00:32:16,350 --> 00:32:18,240 the altimeter. 666 00:32:18,240 --> 00:32:24,300 Same issue when you go from high temperature to low temperature. 667 00:32:24,300 --> 00:32:26,740 So I just came back from Jacksonville, Florida, 668 00:32:26,740 --> 00:32:29,680 in the Cirrus, so I went from high temperature. 669 00:32:29,680 --> 00:32:32,460 And at an indicated altitude of 3,500 feet, 670 00:32:32,460 --> 00:32:36,210 I was actually a bit higher above the earth than here 671 00:32:36,210 --> 00:32:37,665 in cold New England. 672 00:32:37,665 --> 00:32:39,290 So that's another thing to be aware of, 673 00:32:39,290 --> 00:32:41,040 and this becomes important for instrument 674 00:32:41,040 --> 00:32:45,840 flying in very cold conditions like up in the Canadian Arctic. 675 00:32:45,840 --> 00:32:48,990 If you fly indicated altitudes when it's extremely cold, 676 00:32:48,990 --> 00:32:51,900 you'll be closer to the ground than they budgeted for when 677 00:32:51,900 --> 00:32:54,330 they designed the procedure. 678 00:32:54,330 --> 00:32:57,960 OK, vertical speed, if you want to maintain 679 00:32:57,960 --> 00:33:00,630 500 feet per minute climb rate or descent 680 00:33:00,630 --> 00:33:02,770 rate for your passenger's comfort, 681 00:33:02,770 --> 00:33:05,700 then this instrument is your friend. 682 00:33:05,700 --> 00:33:10,260 It does lag so you can't really use this to-- 683 00:33:10,260 --> 00:33:12,420 all these instruments are outputs, not inputs. 684 00:33:12,420 --> 00:33:15,270 Your inputs as a pilot are the attitude and the power. 685 00:33:15,270 --> 00:33:16,830 So you set a power. 686 00:33:16,830 --> 00:33:19,170 You set an attitude like a little bit three degrees 687 00:33:19,170 --> 00:33:22,020 nose up, and then you use these instruments 688 00:33:22,020 --> 00:33:25,210 to verify that you're getting the performance that you want. 689 00:33:25,210 --> 00:33:27,540 Especially true for the vertical-speed indicator 690 00:33:27,540 --> 00:33:30,210 because the instrument itself has lag in addition 691 00:33:30,210 --> 00:33:34,130 to the lags that come from just the inertia of the aircraft. 692 00:33:34,130 --> 00:33:40,050 OK, under the hood it's gotten this calibrated leak. 693 00:33:40,050 --> 00:33:47,220 I don't really-- anyway, it's another fancy instrument 694 00:33:47,220 --> 00:33:50,280 than a mechanical engineer should tell you about. 695 00:33:50,280 --> 00:33:52,170 All right, gyroscopes, the main property 696 00:33:52,170 --> 00:33:54,240 is you can use them for an aircraft instrument 697 00:33:54,240 --> 00:33:59,640 because it will try to stay where it is relative to space. 698 00:33:59,640 --> 00:34:01,440 It has to be corrected. 699 00:34:01,440 --> 00:34:05,460 In the instruments, it's really where gyroscopic precession has 700 00:34:05,460 --> 00:34:07,260 to be considered because think about it, 701 00:34:07,260 --> 00:34:09,750 you're going to be showing the pilot various things 702 00:34:09,750 --> 00:34:11,570 on the face of the instruments. 703 00:34:11,570 --> 00:34:14,820 So you want to sure that the deflections 704 00:34:14,820 --> 00:34:18,090 correspond to what's happening out there in the real world. 705 00:34:18,090 --> 00:34:22,710 Again, this is covered in the Pilot's Handbook. 706 00:34:22,710 --> 00:34:28,380 This just tells you, again, if you kick a gyro up at the top, 707 00:34:28,380 --> 00:34:32,909 instead of the axis of the gyroscope rotating downward, 708 00:34:32,909 --> 00:34:35,100 it's actually going to yaw to the left. 709 00:34:35,100 --> 00:34:39,050 That's gyroscopic precession. 710 00:34:39,050 --> 00:34:43,340 Turn coordinator, it has a gyro to tell you 711 00:34:43,340 --> 00:34:46,670 that little airplane, if you're doing a standard rate turn, 712 00:34:46,670 --> 00:34:52,909 it'll go to this point here. 713 00:34:52,909 --> 00:34:55,460 That's a two-minute turn that'll take you 714 00:34:55,460 --> 00:34:57,199 two minutes to go 360 degrees. 715 00:35:00,000 --> 00:35:03,470 And it's a backup to a vacuum-powered attitude 716 00:35:03,470 --> 00:35:04,670 indicator. 717 00:35:04,670 --> 00:35:07,430 It also has this completely separate function 718 00:35:07,430 --> 00:35:09,080 of a little ball in-- 719 00:35:09,080 --> 00:35:10,940 I think, it's in kerosene actually-- 720 00:35:10,940 --> 00:35:12,860 so it's a little ball in fluid. 721 00:35:12,860 --> 00:35:16,162 And in a perfectly coordinated turn, 722 00:35:16,162 --> 00:35:17,870 you should actually feel like you're just 723 00:35:17,870 --> 00:35:19,737 standing on the ground at 1G, and the ball 724 00:35:19,737 --> 00:35:21,320 should stay right there in the center. 725 00:35:25,610 --> 00:35:27,880 All right, turn coordinator, it can tell you 726 00:35:27,880 --> 00:35:30,910 whether you're slipping, skidding, or coordinated. 727 00:35:30,910 --> 00:35:32,680 So if you're coordinated, as I said, 728 00:35:32,680 --> 00:35:37,010 it's just like sitting in a chair and not moving. 729 00:35:37,010 --> 00:35:41,710 If you're slipping, if you have any trouble visualizing this 730 00:35:41,710 --> 00:35:44,170 you can just reflect on the fact that you 731 00:35:44,170 --> 00:35:46,910 have to step on the ball to fix the problem. 732 00:35:46,910 --> 00:35:49,000 So here your airplane's in a right turn, 733 00:35:49,000 --> 00:35:51,610 and it's telling you you have to step on the right rudder 734 00:35:51,610 --> 00:35:54,610 and bring the nose more around to the right in order 735 00:35:54,610 --> 00:35:55,990 to be coordinated. 736 00:35:55,990 --> 00:35:58,090 So that is a slipping turn. 737 00:35:58,090 --> 00:36:00,310 So here's our airplane. 738 00:36:00,310 --> 00:36:04,000 We've banked the wings, but we've 739 00:36:04,000 --> 00:36:06,897 got the nose still kind of pointed 740 00:36:06,897 --> 00:36:07,980 where we used to be going. 741 00:36:07,980 --> 00:36:09,438 So it's telling us you need to kick 742 00:36:09,438 --> 00:36:12,950 a little bit of right rudder and have a coordinated turn. 743 00:36:12,950 --> 00:36:14,040 Skidding is the other way. 744 00:36:14,040 --> 00:36:16,500 For some reason, we have too much right rudder in there, 745 00:36:16,500 --> 00:36:19,650 and we need to back off of it or hit some left rudder 746 00:36:19,650 --> 00:36:21,783 and bring it back. 747 00:36:21,783 --> 00:36:23,450 Again, this is something, it'll become-- 748 00:36:23,450 --> 00:36:25,783 you know, eventually you develop a sort of a feel for it 749 00:36:25,783 --> 00:36:28,722 in the seat of your pants, and you'll just do it naturally. 750 00:36:28,722 --> 00:36:30,180 And actually, modern aircraft don't 751 00:36:30,180 --> 00:36:33,582 have a whole lot of, what's called, adverse yaw, 752 00:36:33,582 --> 00:36:35,040 so if you try to turn them, they're 753 00:36:35,040 --> 00:36:37,080 not really going to get out of coordination 754 00:36:37,080 --> 00:36:39,910 to any large extent. 755 00:36:39,910 --> 00:36:41,612 All right, attitude indicator. 756 00:36:44,710 --> 00:36:47,740 If you're either in level flight or on the ramp, 757 00:36:47,740 --> 00:36:50,140 this little airplane pointer here in the middle-- 758 00:36:50,140 --> 00:36:51,430 that little orange thing-- 759 00:36:51,430 --> 00:36:54,220 is just something that you can rotate up and down. 760 00:36:54,220 --> 00:36:56,080 It's basically just a reminder for you 761 00:36:56,080 --> 00:36:58,990 of what attitude will produce level flight. 762 00:36:58,990 --> 00:37:01,360 It might be a couple degrees pitched up or down, 763 00:37:01,360 --> 00:37:05,240 but you just set it to whatever it is. 764 00:37:05,240 --> 00:37:09,170 This is a gyro that's free to move in two directions, 765 00:37:09,170 --> 00:37:14,930 and as it moves, it moves this bank index, 766 00:37:14,930 --> 00:37:19,448 I guess, on the face of the gyro is what they're calling it-- 767 00:37:19,448 --> 00:37:20,990 or maybe that just is the bank index. 768 00:37:20,990 --> 00:37:23,810 It's moving the whole artificial horizon 769 00:37:23,810 --> 00:37:26,900 on the face of the gyro. 770 00:37:26,900 --> 00:37:29,930 So the important thing is it's a gyro at 2 gimbals. 771 00:37:29,930 --> 00:37:32,550 In aerobatic airplanes, this design doesn't work very well. 772 00:37:32,550 --> 00:37:35,120 It tends to get damaged by all of the extreme maneuvers 773 00:37:35,120 --> 00:37:36,770 and g-forces. 774 00:37:36,770 --> 00:37:39,600 As a pilot, what do you need to know about this? 775 00:37:39,600 --> 00:37:42,050 It's worth knowing how to read it. 776 00:37:42,050 --> 00:37:45,100 In your flight training, you'll do, so-called, steep turns 777 00:37:45,100 --> 00:37:47,240 where you'll bank to a 45-degree angle. 778 00:37:47,240 --> 00:37:50,010 It's mostly a visual maneuver where you look outside, 779 00:37:50,010 --> 00:37:52,700 but the attitude indicator is a good reference, again, 780 00:37:52,700 --> 00:37:56,960 to see whether the picture that you've got of a natural horizon 781 00:37:56,960 --> 00:37:59,810 actually does correspond to a 45-degree bank. 782 00:37:59,810 --> 00:38:02,270 If you go up, I think if you go beyond 60-degree banks, 783 00:38:02,270 --> 00:38:05,581 it's time for your aerobatic airplane and your parachute. 784 00:38:10,010 --> 00:38:12,200 That pointer at the top generally 785 00:38:12,200 --> 00:38:15,950 will be pointed up at the sky however you're maneuvering. 786 00:38:15,950 --> 00:38:18,360 We'll see this in a moment here. 787 00:38:18,360 --> 00:38:24,758 So you can see, let's just pick a level right turn. 788 00:38:24,758 --> 00:38:29,492 So over here, you say, well, that thing at the top 789 00:38:29,492 --> 00:38:30,950 isn't really pointed up at the sky. 790 00:38:30,950 --> 00:38:33,070 It's just pointed off to the left but think about it. 791 00:38:33,070 --> 00:38:34,695 They're just showing you the instrument 792 00:38:34,695 --> 00:38:36,460 as you would see it in the cockpit. 793 00:38:36,460 --> 00:38:40,630 So because the airplanes turn to the right, 794 00:38:40,630 --> 00:38:43,690 that top pointer would actually correspond 795 00:38:43,690 --> 00:38:46,330 to straight up into the sky. 796 00:38:46,330 --> 00:38:48,850 But as you see, it's kind of the same picture you would get. 797 00:38:48,850 --> 00:38:52,390 You're more or less not pitched but you are banked. 798 00:38:52,390 --> 00:38:54,280 If you're going up climbing right bank, 799 00:38:54,280 --> 00:38:56,590 you see you're just pitched up a couple degrees. 800 00:38:56,590 --> 00:39:02,113 There's a little bit more blue here versus here. 801 00:39:02,113 --> 00:39:03,530 As an instrument pilot, you'll get 802 00:39:03,530 --> 00:39:06,860 very good at seeing small differences-- just one or two 803 00:39:06,860 --> 00:39:10,157 degrees of bank or pitch here. 804 00:39:10,157 --> 00:39:11,990 We're about to go into the magnetic compass, 805 00:39:11,990 --> 00:39:13,940 so let's take a break here and we'll 806 00:39:13,940 --> 00:39:16,745 wrap this up after everybody has their pizza. 807 00:39:16,745 --> 00:39:19,130 A few things to remember about magnetic compasses, 808 00:39:19,130 --> 00:39:23,300 and then we're off to Oshkosh which is going to be more fun. 809 00:39:23,300 --> 00:39:25,790 The most important thing is that it only works 810 00:39:25,790 --> 00:39:27,260 when you're straight and level. 811 00:39:27,260 --> 00:39:29,360 And the fundamental insight for this 812 00:39:29,360 --> 00:39:31,790 is the compass is a horizontal thing. 813 00:39:31,790 --> 00:39:34,400 It's only designed to move horizontally. 814 00:39:34,400 --> 00:39:37,040 So if you start tilting it, tilting your aircraft, 815 00:39:37,040 --> 00:39:38,157 one big part of it-- 816 00:39:38,157 --> 00:39:39,740 big part of the problem is the compass 817 00:39:39,740 --> 00:39:44,000 tries to still point itself towards the magnetic north 818 00:39:44,000 --> 00:39:46,410 pole which will cause it to rotate a little bit. 819 00:39:46,410 --> 00:39:48,530 It's a little bit hard to explain 820 00:39:48,530 --> 00:39:50,540 without thinking about it and reading about it 821 00:39:50,540 --> 00:39:52,070 in the Pilot's Handbook. 822 00:39:52,070 --> 00:39:55,310 But the takeaway is that because it has inertia, 823 00:39:55,310 --> 00:39:57,050 and because it's not really fully 824 00:39:57,050 --> 00:40:01,130 free to rotate to point in three dimensions down 825 00:40:01,130 --> 00:40:04,580 to the north pole, you get all these bizarre errors. 826 00:40:04,580 --> 00:40:08,750 Like if you turn away from a heading of north, 827 00:40:08,750 --> 00:40:11,400 it'll initially show a turn in the opposite direction. 828 00:40:11,400 --> 00:40:15,080 And if you accelerate because of the inertia, it'll-- 829 00:40:15,080 --> 00:40:18,840 let's see, accelerate north, and yes. 830 00:40:18,840 --> 00:40:20,888 All right, we'll get into that in a moment. 831 00:40:20,888 --> 00:40:21,930 Even I can't remember it. 832 00:40:21,930 --> 00:40:23,763 Just remember don't look at it unless you're 833 00:40:23,763 --> 00:40:25,780 straight and level. 834 00:40:25,780 --> 00:40:29,250 The true magnetic-- I think actually the north pole-- 835 00:40:29,250 --> 00:40:31,590 the magnetic north pole, I heard recently 836 00:40:31,590 --> 00:40:34,710 there was some kind of significant movement. 837 00:40:34,710 --> 00:40:37,890 Anyway, it's moved quite a bit since 1632 838 00:40:37,890 --> 00:40:40,080 as you see here on this chart. 839 00:40:45,210 --> 00:40:48,080 Because true north is not equal to magnetic north, and the kind 840 00:40:48,080 --> 00:40:51,320 of primary source of direction that you have in your aircraft 841 00:40:51,320 --> 00:40:54,530 is a magnetic source, on the charts, 842 00:40:54,530 --> 00:40:58,250 you end up getting these isogonic lines that tell you 843 00:40:58,250 --> 00:41:00,350 how much correction to apply. 844 00:41:00,350 --> 00:41:04,560 So here you can see 14 degrees west. 845 00:41:04,560 --> 00:41:08,580 That tells you-- because if east is least, and west is best-- 846 00:41:08,580 --> 00:41:11,370 if we want to fly straight true north, 847 00:41:11,370 --> 00:41:15,630 we actually have to steer zero plus 14. 848 00:41:15,630 --> 00:41:18,970 So zero is the true north course, add 14. 849 00:41:18,970 --> 00:41:22,470 And if we see 14 on our compass, or between 10 and 20 850 00:41:22,470 --> 00:41:26,670 on our compass, between 1 and 2 I guess it would be indicated, 851 00:41:26,670 --> 00:41:29,880 then we're heading true north. 852 00:41:29,880 --> 00:41:33,910 If you forget all of this stuff that I'm telling you-- 853 00:41:33,910 --> 00:41:37,150 which I hope you will because this is a very tedious area-- 854 00:41:37,150 --> 00:41:39,160 you can cheat. 855 00:41:39,160 --> 00:41:41,570 So look at this VOR. 856 00:41:41,570 --> 00:41:44,940 The VOR tells you this is the Block Island VOR. 857 00:41:44,940 --> 00:41:46,590 This is another great place to fly. 858 00:41:46,590 --> 00:41:47,780 So you land there. 859 00:41:47,780 --> 00:41:48,830 You walk to the beach. 860 00:41:48,830 --> 00:41:50,750 You skip out on the ferry ride. 861 00:41:50,750 --> 00:41:53,300 This is the best arguments for general aviation aircraft 862 00:41:53,300 --> 00:41:56,213 are almost always places that are islands, 863 00:41:56,213 --> 00:41:58,130 and you can't drive there on your Honda Accord 864 00:41:58,130 --> 00:41:59,690 even if you wanted to. 865 00:41:59,690 --> 00:42:05,320 So but you see here, the zero magnetic line is not aligned. 866 00:42:05,320 --> 00:42:06,720 The charge is in true north. 867 00:42:06,720 --> 00:42:08,273 So there is your true north. 868 00:42:08,273 --> 00:42:09,440 There is your zero magnetic. 869 00:42:09,440 --> 00:42:11,900 So you can just see that the variation here 870 00:42:11,900 --> 00:42:13,210 is about 14 degrees. 871 00:42:13,210 --> 00:42:14,780 You wouldn't even need-- and you can 872 00:42:14,780 --> 00:42:17,510 also that east is least, west is best rule, 873 00:42:17,510 --> 00:42:20,570 you can rederive it just by looking at any VOR. 874 00:42:20,570 --> 00:42:25,990 Except don't look at a VOR in Florida 875 00:42:25,990 --> 00:42:29,200 because that's where there is no variation. 876 00:42:29,200 --> 00:42:31,930 But almost any other VOR you can look at and see 877 00:42:31,930 --> 00:42:34,090 what the new rule is. 878 00:42:34,090 --> 00:42:37,280 All right, magnetic deviation. 879 00:42:37,280 --> 00:42:40,240 If you have stuff in the airplane, 880 00:42:40,240 --> 00:42:44,700 it will cause the compass to be a little bit inaccurate. 881 00:42:44,700 --> 00:42:47,100 So they give you this compass card here underneath, 882 00:42:47,100 --> 00:42:49,760 which will give you usually one or two-degree changes 883 00:42:49,760 --> 00:42:56,400 at the most for how you would-- 884 00:42:56,400 --> 00:42:59,760 you know, if you want to fly north magnetic heading, 885 00:42:59,760 --> 00:43:03,720 you might actually steer, I don't know, zero-point-- 886 00:43:03,720 --> 00:43:07,272 steer a course of one or two degrees. 887 00:43:07,272 --> 00:43:09,480 You know, if you bring stuff into the aircraft that's 888 00:43:09,480 --> 00:43:13,080 heavy and metal or magnetic, that can affect your compass. 889 00:43:13,080 --> 00:43:16,253 And actually, in an aircraft with heated windshields, 890 00:43:16,253 --> 00:43:18,420 if you turn on the heated windshield for anti-icing, 891 00:43:18,420 --> 00:43:20,310 and in jets, it's kind of standard 892 00:43:20,310 --> 00:43:21,780 to fly with them on all the time, 893 00:43:21,780 --> 00:43:23,010 the compass becomes useless. 894 00:43:23,010 --> 00:43:26,610 The heated windshields throw it off by 90 degrees. 895 00:43:26,610 --> 00:43:29,030 All right, in the lowest end airplane, 896 00:43:29,030 --> 00:43:31,060 they'll have a directional gyro. 897 00:43:31,060 --> 00:43:34,640 Because of all of those compass errors, you as a pilot, 898 00:43:34,640 --> 00:43:37,780 will basically, just every five or 10 minutes 899 00:43:37,780 --> 00:43:41,830 if it's a really old and bad DG, or maybe every half hour 900 00:43:41,830 --> 00:43:44,950 if it's a decent new one, you'll just look up at the compass 901 00:43:44,950 --> 00:43:47,350 when you're in level unaccelerated flight, 902 00:43:47,350 --> 00:43:54,350 and you'll reset with this knob here down at the bottom. 903 00:43:54,350 --> 00:43:58,220 You'll twist that to align the directional gyro 904 00:43:58,220 --> 00:43:59,300 to the compass. 905 00:43:59,300 --> 00:44:03,020 So the compass is the authority, but it's only an authority 906 00:44:03,020 --> 00:44:04,560 when you're straight and level. 907 00:44:04,560 --> 00:44:09,560 OK, under the hood, notice that this, unlike the attitude 908 00:44:09,560 --> 00:44:13,460 indicator, this only has one gimbal. 909 00:44:13,460 --> 00:44:16,250 And that's really the takeaway for why the attitude indicators 910 00:44:16,250 --> 00:44:18,800 tend to break more often than these other instruments 911 00:44:18,800 --> 00:44:20,780 because they have two gimbals and they're just 912 00:44:20,780 --> 00:44:23,550 a little more fragile overall. 913 00:44:23,550 --> 00:44:26,760 Horizontal situation, everything in flying, 914 00:44:26,760 --> 00:44:28,740 they've tried to make it more idiot-proof, 915 00:44:28,740 --> 00:44:31,292 and the HSI is a great example of something 916 00:44:31,292 --> 00:44:33,000 that was figured out, I don't know, maybe 917 00:44:33,000 --> 00:44:34,860 in the 50s or maybe earlier. 918 00:44:34,860 --> 00:44:40,380 They said, what if we just take that DG and we put 919 00:44:40,380 --> 00:44:42,150 an indicator on here. 920 00:44:42,150 --> 00:44:46,800 This is showing we're trying to go on a heading of about 010-- 921 00:44:46,800 --> 00:44:47,720 just slightly north. 922 00:44:47,720 --> 00:44:50,160 That's this yellow pointer. 923 00:44:50,160 --> 00:44:54,180 We are actually going on a heading of about 020. 924 00:44:54,180 --> 00:44:56,190 Maybe that's because of a wind correction. 925 00:44:56,190 --> 00:44:58,080 There's a wind coming from the right. 926 00:44:58,080 --> 00:45:00,150 And it also integrates your line. 927 00:45:00,150 --> 00:45:04,430 See it shows you with this course deviation indicator 928 00:45:04,430 --> 00:45:06,430 that you're slightly to the right of the course. 929 00:45:06,430 --> 00:45:08,650 The course is a little bit to your left. 930 00:45:08,650 --> 00:45:10,758 And actually, this person, I think, 931 00:45:10,758 --> 00:45:12,800 this pilot is flying an Instrument-Landing-System 932 00:45:12,800 --> 00:45:13,850 approach. 933 00:45:13,850 --> 00:45:17,810 This yellow trapezoid there on the left 934 00:45:17,810 --> 00:45:19,528 and right is showing you where you 935 00:45:19,528 --> 00:45:20,820 are relative to the glideslope. 936 00:45:20,820 --> 00:45:22,310 So you're right on the glideslope. 937 00:45:22,310 --> 00:45:23,750 So basically, all the information 938 00:45:23,750 --> 00:45:27,072 that you need for your flight other than the attitude 939 00:45:27,072 --> 00:45:28,280 is on this single instrument. 940 00:45:28,280 --> 00:45:29,905 If you have everything set up correctly 941 00:45:29,905 --> 00:45:32,000 the radios or the GPS, you really 942 00:45:32,000 --> 00:45:33,800 don't need to look anywhere but here 943 00:45:33,800 --> 00:45:35,100 and at the attitude indicator. 944 00:45:35,100 --> 00:45:36,590 It's a pretty nice idea. 945 00:45:36,590 --> 00:45:40,380 And this is replicated in all of the glass cockpits. 946 00:45:40,380 --> 00:45:42,680 All right, technically advanced aircraft, 947 00:45:42,680 --> 00:45:48,240 here's a photograph of the latest and greatest Cirrus SR22 948 00:45:48,240 --> 00:45:51,240 or 20 cockpit. 949 00:45:51,240 --> 00:45:54,970 You have two big screens. 950 00:45:54,970 --> 00:45:56,410 One's usually called the PFD-- 951 00:45:56,410 --> 00:45:58,590 primary flight display-- one's the MFD-- 952 00:45:58,590 --> 00:46:00,340 the multifunction display-- that shows you 953 00:46:00,340 --> 00:46:04,030 maps and weather and traffic. 954 00:46:04,030 --> 00:46:10,000 This idea came from the big jets from the 80s, I guess, and 90s. 955 00:46:10,000 --> 00:46:13,810 It was adopted in the Cirrus in 2003, 956 00:46:13,810 --> 00:46:17,110 pioneered with an MIT spin called 957 00:46:17,110 --> 00:46:19,810 Avidyne which is a local company. 958 00:46:19,810 --> 00:46:21,820 Garmin kind of took things over. 959 00:46:21,820 --> 00:46:26,150 And most of the aircraft today come with Garmin. 960 00:46:26,150 --> 00:46:28,930 G1000 is a brand name that you might have 961 00:46:28,930 --> 00:46:30,210 heard for a Garmin product. 962 00:46:30,210 --> 00:46:32,050 It's pretty popular. 963 00:46:32,050 --> 00:46:34,090 In some ways, people with older aircraft 964 00:46:34,090 --> 00:46:35,830 are almost better off right now. 965 00:46:35,830 --> 00:46:38,530 There's this huge stream of retrofit stuff 966 00:46:38,530 --> 00:46:42,670 that's very innovative, more so than the comprehensive glass 967 00:46:42,670 --> 00:46:43,810 panels. 968 00:46:43,810 --> 00:46:47,860 And usually, for $30,000 or so an older plane 969 00:46:47,860 --> 00:46:51,300 can be brought up to the modern standard. 970 00:46:51,300 --> 00:46:55,720 OK, what if things are not going well at all? 971 00:46:55,720 --> 00:46:58,720 The ultralights tend to come apart in flight. 972 00:46:58,720 --> 00:47:00,910 Certified airplanes virtually never come apart. 973 00:47:00,910 --> 00:47:04,420 They're just so over-engineered that wings don't fall off, 974 00:47:04,420 --> 00:47:07,150 struts don't fail. 975 00:47:07,150 --> 00:47:09,860 But the two brothers-- 976 00:47:09,860 --> 00:47:12,873 the Klapmeier brothers, from Wisconsin, I believe-- 977 00:47:12,873 --> 00:47:14,290 although the company they started, 978 00:47:14,290 --> 00:47:16,760 Cirrus, is in Duluth, Minnesota-- 979 00:47:16,760 --> 00:47:18,760 they say, look, this parachute would give people 980 00:47:18,760 --> 00:47:21,220 a lot of comfort, and there are some situations 981 00:47:21,220 --> 00:47:24,190 in which it could be useful even in a certified airplane. 982 00:47:24,190 --> 00:47:26,020 So they added it in the Cirrus. 983 00:47:26,020 --> 00:47:28,750 And you pull it, and the rocket chutes the parachute out, 984 00:47:28,750 --> 00:47:30,520 and you float down. 985 00:47:30,520 --> 00:47:32,890 It's becoming more and more popular. 986 00:47:32,890 --> 00:47:38,110 I thought it was a payload-hogging waste of money 987 00:47:38,110 --> 00:47:41,410 when I bought the Cirrus in 2005. 988 00:47:41,410 --> 00:47:44,010 And now that the engine has 2,000 hours on it, 989 00:47:44,010 --> 00:47:46,890 and I'm flying at night, I think that's pretty good. 990 00:47:46,890 --> 00:47:49,030 That's a pretty good parachute. 991 00:47:49,030 --> 00:47:50,890 I don't even mind the $15,000 that we 992 00:47:50,890 --> 00:47:56,940 paid to have it all repacked at the 10-year point. 993 00:47:56,940 --> 00:48:04,422 All right, summary, so piston engines, 994 00:48:04,422 --> 00:48:06,880 they're very fuel-efficient compared to jets at these power 995 00:48:06,880 --> 00:48:08,260 settings. 996 00:48:08,260 --> 00:48:10,930 They have quirks which sounds bad. 997 00:48:10,930 --> 00:48:13,690 You know, one cylinder might be running rough, 998 00:48:13,690 --> 00:48:16,150 but it's better than in a jet world where 999 00:48:16,150 --> 00:48:18,670 if things aren't perfect, the engine just quits or explodes 1000 00:48:18,670 --> 00:48:19,480 or something. 1001 00:48:19,480 --> 00:48:23,650 So turbine engines seldom go bad, but when they do go bad 1002 00:48:23,650 --> 00:48:26,650 it's often with no warning. 1003 00:48:26,650 --> 00:48:29,410 Here's your six-pack. 1004 00:48:29,410 --> 00:48:31,300 The altimeter, remember, is essentially 1005 00:48:31,300 --> 00:48:33,130 measuring a percentage of the atmosphere 1006 00:48:33,130 --> 00:48:34,270 that you're above or below. 1007 00:48:37,100 --> 00:48:40,430 Compass is full of errors except when you're straight and level. 1008 00:48:40,430 --> 00:48:42,438 And also the aircraft manufacturers 1009 00:48:42,438 --> 00:48:43,730 are really systems integrators. 1010 00:48:43,730 --> 00:48:45,397 They're buying the engine from somebody. 1011 00:48:45,397 --> 00:48:47,660 They're buying these instruments like the Garmin G100 1012 00:48:47,660 --> 00:48:49,940 from somebody. 1013 00:48:49,940 --> 00:48:52,160 Study pitot-static failures and the compass areas. 1014 00:48:52,160 --> 00:48:55,960 And they're on the exam, and they're not intuitive. 1015 00:48:55,960 --> 00:48:57,970 Questions. 1016 00:48:57,970 --> 00:49:00,550 This is another picture from that air museum in Bradley. 1017 00:49:00,550 --> 00:49:02,093 They have one of the handful-- 1018 00:49:02,093 --> 00:49:03,760 it's not flying, I don't think, but it's 1019 00:49:03,760 --> 00:49:06,370 restored-- a Boeing B29 bomber. 1020 00:49:06,370 --> 00:49:08,680 And if you want to know why I get defriended 1021 00:49:08,680 --> 00:49:13,330 all the time on Facebook, I posted this picture 1022 00:49:13,330 --> 00:49:18,670 of their turret computer, and I said I found the original iPad 1023 00:49:18,670 --> 00:49:20,250 in the museum. 1024 00:49:20,250 --> 00:49:21,928 That was hashtag not funny. 1025 00:49:21,928 --> 00:49:23,800 [LAUGHTER] 1026 00:49:23,800 --> 00:49:26,050 All right, any questions or should we go into Oshkosh? 1027 00:49:26,050 --> 00:49:28,550 We can have questions. 1028 00:49:28,550 --> 00:49:31,630 Don't ask about those brass and neural things 1029 00:49:31,630 --> 00:49:36,060 because I was a math undergrad and EECS grad student.