1 00:00:00,000 --> 00:00:01,952 [CLICKING] 2 00:00:13,352 --> 00:00:14,810 PHILIP GREENSPUN: All right, folks. 3 00:00:14,810 --> 00:00:15,880 Tina is going to tell you more. 4 00:00:15,880 --> 00:00:17,180 We had a little bit of weight and balance 5 00:00:17,180 --> 00:00:18,850 before that flight planning example, 6 00:00:18,850 --> 00:00:21,970 but Tina is now going to give you the real story. 7 00:00:24,807 --> 00:00:27,140 TINA SRIVASTAVA: So are guys all ready to go out and get 8 00:00:27,140 --> 00:00:29,960 your drone license? 9 00:00:29,960 --> 00:00:30,690 Good. 10 00:00:30,690 --> 00:00:31,480 I'm really glad. 11 00:00:31,480 --> 00:00:34,995 PHILIP GREENSPUN: [INAUDIBLE] 12 00:00:34,995 --> 00:00:36,120 TINA SRIVASTAVA: All right. 13 00:00:36,120 --> 00:00:41,020 Weight and balance So we talked a little bit. 14 00:00:41,020 --> 00:00:43,260 We've actually had quite a few discussions throughout 15 00:00:43,260 --> 00:00:47,310 about stability, about where the center of G 16 00:00:47,310 --> 00:00:49,800 is, how that affects your controllability 17 00:00:49,800 --> 00:00:51,070 of the aircraft. 18 00:00:51,070 --> 00:00:53,910 So weight and balance is not only an important thing 19 00:00:53,910 --> 00:00:55,770 to know, but it's a required thing 20 00:00:55,770 --> 00:00:59,080 that you have to do before you go flying each time. 21 00:00:59,080 --> 00:01:01,260 And one thing that's also relevant 22 00:01:01,260 --> 00:01:04,090 is to understand the center of gravity, 23 00:01:04,090 --> 00:01:06,090 and you want to make sure that center of gravity 24 00:01:06,090 --> 00:01:10,430 is within the limits for your given aircraft. 25 00:01:10,430 --> 00:01:13,360 So we talked about-- 26 00:01:13,360 --> 00:01:16,660 yesterday, when we were talking about aerodynamic flight, 27 00:01:16,660 --> 00:01:19,330 that certain aircraft have to be reinforced 28 00:01:19,330 --> 00:01:21,050 to do certain operations. 29 00:01:21,050 --> 00:01:22,860 So again, it really has to do with that. 30 00:01:22,860 --> 00:01:25,360 And by the way, from yesterday, mark 31 00:01:25,360 --> 00:01:29,815 left behind some of his aerodynamic procedure diagrams. 32 00:01:29,815 --> 00:01:33,340 So if you want to take a look at that, those are up front. 33 00:01:33,340 --> 00:01:34,840 Well, one thing that really you have 34 00:01:34,840 --> 00:01:37,900 to keep in mind in terms of what the aircraft can handle 35 00:01:37,900 --> 00:01:40,540 is just what is the max gross weight. 36 00:01:40,540 --> 00:01:45,700 So what can this airframe sustain, in terms of stresses 37 00:01:45,700 --> 00:01:47,570 on its body. 38 00:01:47,570 --> 00:01:51,350 We also talked this morning about performance 39 00:01:51,350 --> 00:01:56,270 and discussed certain things like the distance-- 40 00:01:56,270 --> 00:01:59,480 the length of the runway and the distance you need to take off 41 00:01:59,480 --> 00:02:02,960 are affected by how the airplane is weighted. 42 00:02:02,960 --> 00:02:06,410 So we're going to talk about those things specifically, 43 00:02:06,410 --> 00:02:08,780 and then one thing I have on here 44 00:02:08,780 --> 00:02:11,300 is if you go over your gross weight, 45 00:02:11,300 --> 00:02:14,600 then you get into test pilot territory, 46 00:02:14,600 --> 00:02:16,557 and right after this-- 47 00:02:16,557 --> 00:02:18,140 we'll grab lunch and come back-- we'll 48 00:02:18,140 --> 00:02:20,750 hear from [INAUDIBLE],, a test pilot who's 49 00:02:20,750 --> 00:02:24,450 going to tell you some really cool things as well. 50 00:02:24,450 --> 00:02:27,470 All right, so it's just some basic terms to get started off. 51 00:02:27,470 --> 00:02:30,320 So when you're thinking about an aircraft, 52 00:02:30,320 --> 00:02:33,920 one piece of information is its standard empty weight. 53 00:02:33,920 --> 00:02:36,140 So that's the weight of the airplane, 54 00:02:36,140 --> 00:02:39,110 and there's also some fuel in the tank 55 00:02:39,110 --> 00:02:43,670 that sometimes it's hard to drain, and when you refill, 56 00:02:43,670 --> 00:02:47,090 that fuel sits at the bottom and can't be used by the aircraft, 57 00:02:47,090 --> 00:02:49,370 so that's the unusable fuel, and then 58 00:02:49,370 --> 00:02:51,650 there's some different fluids and fuel 59 00:02:51,650 --> 00:02:52,940 oil inside the aircraft. 60 00:02:52,940 --> 00:02:55,490 So all those count in the calculation 61 00:02:55,490 --> 00:02:57,410 of the standard empty weight. 62 00:02:57,410 --> 00:02:59,390 There's also the basic empty weight, 63 00:02:59,390 --> 00:03:02,330 where you have some optional equipment inside, 64 00:03:02,330 --> 00:03:07,970 and we'll go to a aircraft's POH to look into what it actually 65 00:03:07,970 --> 00:03:09,365 reports about what it contains. 66 00:03:12,380 --> 00:03:13,790 There's also a good rule of thumb 67 00:03:13,790 --> 00:03:17,450 to know about what weight you're going to associate 68 00:03:17,450 --> 00:03:19,710 with the per gallon of fuel. 69 00:03:19,710 --> 00:03:23,240 So it's generally a good number is six pounds. 70 00:03:23,240 --> 00:03:24,710 For the fuel that you'll be using, 71 00:03:24,710 --> 00:03:28,965 it's slightly more for different types of fuel. 72 00:03:28,965 --> 00:03:30,590 So right at the beginning of the class, 73 00:03:30,590 --> 00:03:33,890 we talked about weight, which is the force pulling 74 00:03:33,890 --> 00:03:39,170 the aircraft down, which has to oppose the lift pulling it up. 75 00:03:39,170 --> 00:03:43,650 So the weight actually becomes less as you burn fuel. 76 00:03:43,650 --> 00:03:46,670 So when you take off, you have all the fuel on the aircraft. 77 00:03:46,670 --> 00:03:48,560 As you've been flying for a while, that 78 00:03:48,560 --> 00:03:52,820 fuel is used in the aircraft has less weight. 79 00:03:52,820 --> 00:03:55,960 So there's a fully loaded aircraft. 80 00:03:55,960 --> 00:03:59,020 Has something called the maximum ramp weight. 81 00:03:59,020 --> 00:04:02,530 So that has fuel that will be expended even 82 00:04:02,530 --> 00:04:05,440 when it's just taxiing over to the runway, 83 00:04:05,440 --> 00:04:08,590 and so you make certain assumptions about how 84 00:04:08,590 --> 00:04:10,240 much fuel you'll actually burn off 85 00:04:10,240 --> 00:04:14,710 just taxiing up to the runway and then before you take off. 86 00:04:14,710 --> 00:04:17,110 And so when you're calculating the weight of the airplane 87 00:04:17,110 --> 00:04:19,029 when it takes off, it'll be slightly 88 00:04:19,029 --> 00:04:21,940 different than how you fueled it when it was sitting parking 89 00:04:21,940 --> 00:04:24,580 on the ramp. 90 00:04:24,580 --> 00:04:27,500 OK, some of the biggest things that you 91 00:04:27,500 --> 00:04:29,870 would keep in mind that you change every time you 92 00:04:29,870 --> 00:04:31,160 get into the airplane. 93 00:04:31,160 --> 00:04:33,050 So there's the weight of the passengers, 94 00:04:33,050 --> 00:04:34,760 the baggage you take with you, and then 95 00:04:34,760 --> 00:04:39,260 how much fuel you fill the plane with before you take off. 96 00:04:39,260 --> 00:04:43,890 So the payload in this case is the passengers and the cargo. 97 00:04:43,890 --> 00:04:46,190 So whatever baggage and the weight of those bags 98 00:04:46,190 --> 00:04:49,190 that you take with you. 99 00:04:49,190 --> 00:04:53,160 So one thing to keep in mind in addition to just the weight, 100 00:04:53,160 --> 00:04:57,450 we have to figure out where that vector, that force vector, 101 00:04:57,450 --> 00:04:59,260 acts on the aircraft. 102 00:04:59,260 --> 00:05:01,253 If all of the weight is really at the front, 103 00:05:01,253 --> 00:05:02,670 you might have a center of gravity 104 00:05:02,670 --> 00:05:06,360 at the front, which will create a moment on the airplane. 105 00:05:06,360 --> 00:05:09,040 So it'll cause it to bend in a particular direction. 106 00:05:09,040 --> 00:05:10,650 And if all that weight was acting 107 00:05:10,650 --> 00:05:12,025 at the back of the plane, you had 108 00:05:12,025 --> 00:05:14,820 a lot of really heavy bricks at your tail, which is not 109 00:05:14,820 --> 00:05:17,520 a good idea, it would cause that force vector 110 00:05:17,520 --> 00:05:19,740 to act over here and create a moment. 111 00:05:19,740 --> 00:05:23,170 So that's all related to torque, which we talked about before. 112 00:05:23,170 --> 00:05:25,710 So it's also important, not just to calculate 113 00:05:25,710 --> 00:05:27,570 what the weight is of the airplane 114 00:05:27,570 --> 00:05:29,910 once everybody and everything is inside, 115 00:05:29,910 --> 00:05:33,540 but also how that weight is distributed in the airplane 116 00:05:33,540 --> 00:05:35,880 and how it affects the airplane's center of gravity. 117 00:05:38,780 --> 00:05:41,970 All right, so I think that many of you have already-- 118 00:05:41,970 --> 00:05:44,270 It looks like most folks in the rooms 119 00:05:44,270 --> 00:05:47,360 were either MIT undergrad or grad student, which 120 00:05:47,360 --> 00:05:50,240 means you already understand some of these basic physics 121 00:05:50,240 --> 00:05:52,820 terms about torque and moment, so we'll 122 00:05:52,820 --> 00:05:55,220 discover them very briefly. 123 00:05:55,220 --> 00:05:58,790 The moment is the weight times the arm. 124 00:05:58,790 --> 00:06:02,900 So basically where the wait is times how far away it 125 00:06:02,900 --> 00:06:05,900 is from a particular location that you're calculating it 126 00:06:05,900 --> 00:06:06,800 from. 127 00:06:06,800 --> 00:06:10,140 So we're going to do a couple basic examples. 128 00:06:10,140 --> 00:06:12,090 So we have a seesaw here. 129 00:06:12,090 --> 00:06:15,980 So in this case, whenever you're calculating your moment, 130 00:06:15,980 --> 00:06:17,630 you have to pick a reference point 131 00:06:17,630 --> 00:06:21,690 and make sure you're consistent as you use it. 132 00:06:21,690 --> 00:06:25,210 So in this case, they have a-- 133 00:06:25,210 --> 00:06:27,620 their data point is at that triangle 134 00:06:27,620 --> 00:06:29,990 at that fulcrum in the middle, and so they 135 00:06:29,990 --> 00:06:33,260 have a moment on the right and a moment on the left. 136 00:06:33,260 --> 00:06:35,840 So you see various rectangles that 137 00:06:35,840 --> 00:06:39,440 represent different objects or different weight, 138 00:06:39,440 --> 00:06:40,670 and then they calculate it. 139 00:06:40,670 --> 00:06:45,290 So that blue box that's five pounds is 10 inches away. 140 00:06:45,290 --> 00:06:48,170 So to figure out what the moment is that it applies, 141 00:06:48,170 --> 00:06:52,330 you just calculate the weight times how far away is. 142 00:06:52,330 --> 00:06:56,350 OK, so in order to figure out what the center of gravity is, 143 00:06:56,350 --> 00:06:59,290 you might want to consider where you're 144 00:06:59,290 --> 00:07:00,830 doing that reference point. 145 00:07:00,830 --> 00:07:02,890 So rather than doing the reference point 146 00:07:02,890 --> 00:07:05,583 from right in the middle of the aircraft, in this case, 147 00:07:05,583 --> 00:07:06,750 they're starting at the end. 148 00:07:06,750 --> 00:07:08,500 So where that yellow line is where it says 149 00:07:08,500 --> 00:07:11,710 datum is where they're starting, and then they're 150 00:07:11,710 --> 00:07:14,660 using the length from that same reference point. 151 00:07:14,660 --> 00:07:17,650 So now you have a purple box of five pounds 152 00:07:17,650 --> 00:07:21,280 that's 10 inches from that datum, and then three pounds 153 00:07:21,280 --> 00:07:23,650 then a green weight that's father, 154 00:07:23,650 --> 00:07:26,830 and the red box that's the farthest away. 155 00:07:26,830 --> 00:07:30,840 So here they've listed all those different boxes 156 00:07:30,840 --> 00:07:34,660 and the weight of each of those boxes times how far it is. 157 00:07:34,660 --> 00:07:37,780 You multiply that to get the moment that it applies. 158 00:07:37,780 --> 00:07:40,420 And use that to calculate the location 159 00:07:40,420 --> 00:07:41,890 of the center of gravity. 160 00:07:45,140 --> 00:07:49,160 And just in terms of if you've been on a seesaw before, 161 00:07:49,160 --> 00:07:51,893 who has been on a seesaw before? 162 00:07:51,893 --> 00:07:52,560 All right, good. 163 00:07:52,560 --> 00:07:54,030 I'm glad. 164 00:07:54,030 --> 00:07:57,090 So as you know that that fulcrum or where 165 00:07:57,090 --> 00:07:59,520 that triangle is, if you put that triangle 166 00:07:59,520 --> 00:08:01,150 at the center of gravity. 167 00:08:01,150 --> 00:08:04,343 So all the kids sitting on one side of the seesaw 168 00:08:04,343 --> 00:08:05,760 weigh the same as the kids sitting 169 00:08:05,760 --> 00:08:08,640 on the other side of the seesaw at the appropriate lengths 170 00:08:08,640 --> 00:08:10,830 away, so they're applying the same moment. 171 00:08:10,830 --> 00:08:12,940 Then the fulcrum balances. 172 00:08:12,940 --> 00:08:15,750 So if we determined what the center of gravity 173 00:08:15,750 --> 00:08:18,618 of this airplane was and I put my finger there, 174 00:08:18,618 --> 00:08:20,160 then it would balance and it wouldn't 175 00:08:20,160 --> 00:08:22,400 tilt one way or the other. 176 00:08:22,400 --> 00:08:25,380 So that's the whole idea. 177 00:08:25,380 --> 00:08:28,980 So for a given aircraft, there is not only 178 00:08:28,980 --> 00:08:33,210 the center of gravity, but in the testing process, 179 00:08:33,210 --> 00:08:36,480 they understand what is that approved range of where 180 00:08:36,480 --> 00:08:39,780 that center of gravity can be such that the aircraft is still 181 00:08:39,780 --> 00:08:41,100 stable. 182 00:08:41,100 --> 00:08:44,220 So if you're thinking about putting a lot of weight 183 00:08:44,220 --> 00:08:47,820 at the front of the aircraft and less weight 184 00:08:47,820 --> 00:08:50,250 at the back of the aircraft, then the center of gravity 185 00:08:50,250 --> 00:08:52,590 moves forward, and there's a limit 186 00:08:52,590 --> 00:08:55,350 to how far forward that center of gravity 187 00:08:55,350 --> 00:08:59,160 can be that allows the plane still to be stable. 188 00:08:59,160 --> 00:09:01,740 So that's the forward CG limit, and then you 189 00:09:01,740 --> 00:09:03,120 see the same thing at the back. 190 00:09:03,120 --> 00:09:06,330 Aft just means back, so how far back the center of gravity 191 00:09:06,330 --> 00:09:09,010 can be. 192 00:09:09,010 --> 00:09:10,840 All right, so we've already discussed some 193 00:09:10,840 --> 00:09:14,320 of the performance things, but just to just to remind you, 194 00:09:14,320 --> 00:09:18,280 what are some of the things that can happen if your air plane is 195 00:09:18,280 --> 00:09:20,540 overloaded? 196 00:09:20,540 --> 00:09:22,670 You want to just a shout out some things 197 00:09:22,670 --> 00:09:24,230 that you would experience if you have 198 00:09:24,230 --> 00:09:27,314 a very, very heavy airplane. 199 00:09:27,314 --> 00:09:29,110 AUDIENCE: Longer take off. 200 00:09:29,110 --> 00:09:31,600 TINA SRIVASTAVA: Yes, very good. 201 00:09:31,600 --> 00:09:33,760 Just to repeat it, longer to take off. 202 00:09:33,760 --> 00:09:37,010 So we have takeoff and landing distances increase. 203 00:09:37,010 --> 00:09:39,280 So if you have a very heavy airplane, 204 00:09:39,280 --> 00:09:44,085 you may not be able to take off from a short field runway. 205 00:09:44,085 --> 00:09:45,460 And then of course it was talking 206 00:09:45,460 --> 00:09:49,990 about if your aircraft gets outside the approved envelope, 207 00:09:49,990 --> 00:09:52,380 it will talk about what we mean by envelope, 208 00:09:52,380 --> 00:09:57,640 then it hasn't been tested to be stable at those areas, 209 00:09:57,640 --> 00:10:00,340 and so now you've become a test pilot, which you may not 210 00:10:00,340 --> 00:10:01,490 want to do. 211 00:10:01,490 --> 00:10:05,630 Again, we're going to hear from a test pilot very soon. 212 00:10:05,630 --> 00:10:07,560 OK, so what happens if-- not just 213 00:10:07,560 --> 00:10:09,480 that it's overloaded, maybe it's still 214 00:10:09,480 --> 00:10:12,910 within the envelope for the total amount of weight, 215 00:10:12,910 --> 00:10:15,210 but what if the center of gravity 216 00:10:15,210 --> 00:10:19,080 has moved too far forward and pass that forward CG limit. 217 00:10:19,080 --> 00:10:22,500 So your plane naturally wants to be nose down. 218 00:10:22,500 --> 00:10:24,060 So what is the impact of that? 219 00:10:28,240 --> 00:10:30,450 Well, it'd be harder to climb, right? 220 00:10:30,450 --> 00:10:32,900 It's harder to climb because your nose keeps 221 00:10:32,900 --> 00:10:36,350 pulling it down, for example. 222 00:10:36,350 --> 00:10:39,650 What does it mean to have a stall speed increased? 223 00:10:39,650 --> 00:10:41,424 Is that a good thing? 224 00:10:41,424 --> 00:10:43,322 AUDIENCE: No. 225 00:10:43,322 --> 00:10:44,530 TINA SRIVASTAVA: And why not? 226 00:10:44,530 --> 00:10:45,820 Why is it not a good thing? 227 00:10:49,540 --> 00:10:51,870 AUDIENCE: [INAUDIBLE] 228 00:10:51,870 --> 00:10:54,450 TINA SRIVASTAVA: Yeah, so basically, if your stall speed 229 00:10:54,450 --> 00:10:58,590 has increased, that means you're likely to stall at a higher 230 00:10:58,590 --> 00:10:59,530 speed. 231 00:10:59,530 --> 00:11:04,020 So if traditionally can fly at 60 knots 232 00:11:04,020 --> 00:11:07,260 without stalling but that stall speed has increased from 233 00:11:07,260 --> 00:11:09,900 say 40 knots up to 60 knots, that 234 00:11:09,900 --> 00:11:11,460 means that when you traditionally 235 00:11:11,460 --> 00:11:13,320 have been able to fly safely at 60 knots, 236 00:11:13,320 --> 00:11:15,000 you could actually stall at 60 knots. 237 00:11:15,000 --> 00:11:19,250 So an increased stall speed is bad. 238 00:11:19,250 --> 00:11:20,960 And what about an aft CG? 239 00:11:20,960 --> 00:11:24,170 Having the weight too far to the back. 240 00:11:24,170 --> 00:11:27,915 What is the impact there? 241 00:11:27,915 --> 00:11:29,390 AUDIENCE: They pitch up. 242 00:11:29,390 --> 00:11:30,260 TINA SRIVASTAVA: They tend to pitch up. 243 00:11:30,260 --> 00:11:30,760 Right. 244 00:11:30,760 --> 00:11:35,150 And so one thing that they are talking about here is flare. 245 00:11:35,150 --> 00:11:38,810 So this is when you're coming into land, you go down, 246 00:11:38,810 --> 00:11:43,400 but then you flare up, and it could actually over flare, 247 00:11:43,400 --> 00:11:46,220 and that can cause some really strange things when you're 248 00:11:46,220 --> 00:11:47,870 trying to land, such as bouncing, 249 00:11:47,870 --> 00:11:49,720 and you definitely don't want to do that. 250 00:11:49,720 --> 00:11:51,470 But all of these things you might actually 251 00:11:51,470 --> 00:11:54,260 just notice when you're feeling the airplane. 252 00:11:54,260 --> 00:11:56,930 It acts differently than you want it to act. 253 00:11:59,660 --> 00:12:02,840 So here's just basically a cross section. 254 00:12:02,840 --> 00:12:05,900 If you took off the wings and the top of the fuselage 255 00:12:05,900 --> 00:12:07,340 and you were looking at the plane, 256 00:12:07,340 --> 00:12:10,140 it shows you the pilot sitting in the left seat, 257 00:12:10,140 --> 00:12:13,490 a passenger in the right seat, two passengers in the back. 258 00:12:13,490 --> 00:12:17,210 This one actually has a third row of passengers, and then 259 00:12:17,210 --> 00:12:19,280 two baggage compartments. 260 00:12:19,280 --> 00:12:20,960 So this is just showing-- 261 00:12:20,960 --> 00:12:23,210 traditionally, when you're loading up an airplane, 262 00:12:23,210 --> 00:12:26,300 they payload again is your passengers and your baggage, 263 00:12:26,300 --> 00:12:28,225 where do they sit? 264 00:12:28,225 --> 00:12:30,350 So now I'm going to go over to this document viewer 265 00:12:30,350 --> 00:12:32,130 and talk about specific airplane. 266 00:12:32,130 --> 00:12:39,220 The plane I like to fly, a Cessna 172. 267 00:12:39,220 --> 00:12:44,310 OK, so this book is talking about a particular aircraft, 268 00:12:44,310 --> 00:12:48,520 a Skyhawk, so it's a Cessna 172. 269 00:12:48,520 --> 00:12:50,290 This is a plane that many of you guys 270 00:12:50,290 --> 00:12:53,110 might use as a flying aircraft. 271 00:12:53,110 --> 00:12:54,640 We've also talked about for example 272 00:12:54,640 --> 00:12:57,760 a Piper, which is a low wing airplane that you might use. 273 00:12:57,760 --> 00:12:59,260 So this is what a Cessna looks like, 274 00:12:59,260 --> 00:13:02,770 and it has a tricycle gear at the bottom. 275 00:13:02,770 --> 00:13:05,550 Whatever plane you are using for training, 276 00:13:05,550 --> 00:13:07,960 I would get very familiar with this book, 277 00:13:07,960 --> 00:13:11,550 and in particular, remember what the table of contents is. 278 00:13:11,550 --> 00:13:16,440 Because when you get your oral exam on your FAA examination, 279 00:13:16,440 --> 00:13:18,390 it's OK if you don't remember everything. 280 00:13:18,390 --> 00:13:21,180 What's really great is if you know how to find information, 281 00:13:21,180 --> 00:13:24,630 and you can say, hey, if I didn't remember this, 282 00:13:24,630 --> 00:13:27,480 I would go look at my POH, and I would go look 283 00:13:27,480 --> 00:13:30,850 at the weight and balance section, section 6 of my book, 284 00:13:30,850 --> 00:13:33,870 and I'd be able to flip and find this information very quickly. 285 00:13:33,870 --> 00:13:36,113 So oftentimes, you'll get questions in that oral exam 286 00:13:36,113 --> 00:13:37,530 where they would ask how you would 287 00:13:37,530 --> 00:13:39,630 go about finding information. 288 00:13:39,630 --> 00:13:41,850 We discussed that a lot with regard to weather data. 289 00:13:41,850 --> 00:13:43,600 What are the sources of weather data, 290 00:13:43,600 --> 00:13:45,450 so with regard to weight and balance, 291 00:13:45,450 --> 00:13:47,580 the information about your airplane 292 00:13:47,580 --> 00:13:51,720 is found with a book made about your particular airplane. 293 00:13:51,720 --> 00:13:54,220 And if you're at a particular flight school, 294 00:13:54,220 --> 00:13:56,840 and we'll show you that in an example, 295 00:13:56,840 --> 00:13:59,340 they might have a-- they most likely have all of this weight 296 00:13:59,340 --> 00:14:02,040 and balance information listed in a spreadsheet, 297 00:14:02,040 --> 00:14:04,110 sometimes it's accessible online so you 298 00:14:04,110 --> 00:14:07,380 know for your exact airplane what its gross weight is. 299 00:14:10,040 --> 00:14:14,320 So if we flip to that section 6, it 300 00:14:14,320 --> 00:14:16,660 has a fair amount of information, including 301 00:14:16,660 --> 00:14:18,340 the picture we just showed you. 302 00:14:21,210 --> 00:14:24,060 So it talks about-- 303 00:14:24,060 --> 00:14:26,730 in this case, there are only two rows of seats. 304 00:14:26,730 --> 00:14:29,460 So that the pilot and passenger, one row of seats, 305 00:14:29,460 --> 00:14:32,912 so it seats four people, and then it has a baggage area. 306 00:14:32,912 --> 00:14:34,620 But what's really important to understand 307 00:14:34,620 --> 00:14:37,800 is that even though the Cessna can fit four people, 308 00:14:37,800 --> 00:14:43,620 it will show you that if you put four 200 pound people in there 309 00:14:43,620 --> 00:14:46,848 with a bunch of bags, you'll actually exceed the allotment. 310 00:14:46,848 --> 00:14:48,390 So just because there are four seats, 311 00:14:48,390 --> 00:14:51,660 doesn't mean you can take four large people on a flight. 312 00:14:51,660 --> 00:14:54,930 Some of it is something we'll keep in mind, 313 00:14:54,930 --> 00:14:58,650 and maybe you can reduce bags and reduce fuel such that you 314 00:14:58,650 --> 00:14:59,970 can make that weight workout. 315 00:15:02,730 --> 00:15:04,220 So we talked about envelopes. 316 00:15:08,580 --> 00:15:12,510 So the envelope is basically a line 317 00:15:12,510 --> 00:15:17,340 on this graph that shows where the center of gravity can be, 318 00:15:17,340 --> 00:15:19,770 and the envelope is where is it safe to be. 319 00:15:19,770 --> 00:15:22,260 So if you're inside the envelope, 320 00:15:22,260 --> 00:15:26,460 so inside this line, if your calculations result 321 00:15:26,460 --> 00:15:28,620 in a center of gravity inside, then you're 322 00:15:28,620 --> 00:15:29,920 within the envelope. 323 00:15:29,920 --> 00:15:32,745 If you're outside of it, then you're not. 324 00:15:32,745 --> 00:15:36,660 You can see a little pencil mark towards the top 325 00:15:36,660 --> 00:15:38,850 where I took a flight recently, and I 326 00:15:38,850 --> 00:15:41,820 was trying to calculate whether or not I was inside 327 00:15:41,820 --> 00:15:43,140 and in fact I was. 328 00:15:43,140 --> 00:15:45,930 And it's OK that I'm right at the edge of the envelope. 329 00:15:45,930 --> 00:15:47,670 As long as you're inside, you're still 330 00:15:47,670 --> 00:15:50,190 with inside the tested limits. 331 00:15:50,190 --> 00:15:52,230 Now, there are two different categories 332 00:15:52,230 --> 00:15:53,640 or two different lines here. 333 00:15:53,640 --> 00:15:56,520 There's a bigger line that says normal category, 334 00:15:56,520 --> 00:15:58,860 and then there's a smaller line-- 335 00:15:58,860 --> 00:16:02,380 smaller envelope-- that's talking about utility category. 336 00:16:02,380 --> 00:16:03,880 Does anyone know what the difference 337 00:16:03,880 --> 00:16:06,338 is between normal and utility? 338 00:16:06,338 --> 00:16:08,290 AUDIENCE: G limits. 339 00:16:08,290 --> 00:16:09,940 TINA SRIVASTAVA: G limits. 340 00:16:09,940 --> 00:16:12,110 Is that what you're going to say? 341 00:16:12,110 --> 00:16:14,200 So there's different restrictions. 342 00:16:16,562 --> 00:16:18,520 One question you might get asked is, how do you 343 00:16:18,520 --> 00:16:19,900 find out where the answer is? 344 00:16:29,312 --> 00:16:30,270 And it's right in here. 345 00:16:30,270 --> 00:16:31,437 Right where you think it is. 346 00:16:34,330 --> 00:16:37,530 And I'm actually going to show you real examples, 347 00:16:37,530 --> 00:16:42,490 so we're going to go through an example of loading up 348 00:16:42,490 --> 00:16:44,087 an airplane. 349 00:16:44,087 --> 00:16:45,670 Don't want to embarrass anyone, but we 350 00:16:45,670 --> 00:16:47,795 might ask some of you what your weight is. 351 00:16:47,795 --> 00:16:48,295 So beware. 352 00:16:51,470 --> 00:16:54,730 So every time you have to calculate your weight 353 00:16:54,730 --> 00:16:56,570 and balance, you can do it by hand, 354 00:16:56,570 --> 00:16:58,990 or you can use a computer to do it, 355 00:16:58,990 --> 00:17:02,560 and I would just caution that you have to double check 356 00:17:02,560 --> 00:17:03,490 all the information. 357 00:17:03,490 --> 00:17:06,819 So here's a great link that tells you 358 00:17:06,819 --> 00:17:11,869 for a particular Cessna 172, a weight and balance calculator. 359 00:17:11,869 --> 00:17:15,790 So here, you can actually type in the empty weight. 360 00:17:15,790 --> 00:17:19,152 Now, there's a big Warning here, use your own AC data. 361 00:17:19,152 --> 00:17:19,985 What is that saying? 362 00:17:23,800 --> 00:17:24,619 What is AC? 363 00:17:24,619 --> 00:17:25,430 AUDIENCE: Aircraft. 364 00:17:25,430 --> 00:17:26,000 TINA SRIVASTAVA: Aircraft. 365 00:17:26,000 --> 00:17:27,380 Use your own aircraft's data. 366 00:17:27,380 --> 00:17:30,440 So look at your actual information 367 00:17:30,440 --> 00:17:33,890 from your school to figure out for the plane 368 00:17:33,890 --> 00:17:38,270 that you're renting what those pieces of information are. 369 00:17:38,270 --> 00:17:42,020 So here is a link from east coast aero club 370 00:17:42,020 --> 00:17:44,030 just as an example, and they have 371 00:17:44,030 --> 00:17:46,880 provided for every aircraft that they 372 00:17:46,880 --> 00:17:49,740 have a bunch of information. 373 00:17:53,390 --> 00:17:57,310 So for each aircraft, they have provided the empty weight 374 00:17:57,310 --> 00:18:01,450 and the CG, the moment, gross weight, useful load, 375 00:18:01,450 --> 00:18:04,810 and then they also talk about two different settings 376 00:18:04,810 --> 00:18:05,750 for fuel. 377 00:18:05,750 --> 00:18:09,700 So you can have full fuel or fuel to tabs. 378 00:18:09,700 --> 00:18:13,570 So that is something you'll hear pretty frequently. 379 00:18:13,570 --> 00:18:15,200 Fill the fuel to tabs. 380 00:18:15,200 --> 00:18:19,780 So if you want to have extra mass, extra weight 381 00:18:19,780 --> 00:18:23,120 in your plane, you have some heavier folks flying with you, 382 00:18:23,120 --> 00:18:25,480 you might only want the fuel to tabs. 383 00:18:25,480 --> 00:18:27,550 But if it's just you or you and your instructor 384 00:18:27,550 --> 00:18:29,590 and you want to fly a cross-country flight, 385 00:18:29,590 --> 00:18:31,360 you might want to fuel full. 386 00:18:31,360 --> 00:18:34,760 So these are all things you can change. 387 00:18:34,760 --> 00:18:36,960 This calculator has some restrictions, 388 00:18:36,960 --> 00:18:43,610 which is that the weight is identified here in terms of-- 389 00:18:43,610 --> 00:18:44,945 so they have the oil. 390 00:18:44,945 --> 00:18:48,290 So you might want to check what is the oil 391 00:18:48,290 --> 00:18:50,600 level inside your engine. 392 00:18:50,600 --> 00:18:54,638 For a Cessna 172, six quarts is a really good number to have, 393 00:18:54,638 --> 00:18:56,930 but you check it every time and during your pre-flight. 394 00:18:56,930 --> 00:18:59,365 It could be five quarts, it could be seven quarts, 395 00:18:59,365 --> 00:19:00,740 so you want to double check that. 396 00:19:00,740 --> 00:19:02,980 And of course, if you see that it's low, 397 00:19:02,980 --> 00:19:05,000 four quarts, you really want to ask someone 398 00:19:05,000 --> 00:19:07,700 to fill that up before you go flying. 399 00:19:07,700 --> 00:19:09,980 But the other thing here is you actually 400 00:19:09,980 --> 00:19:13,970 list the weight of the people that are sitting 401 00:19:13,970 --> 00:19:15,680 in the front and the back. 402 00:19:15,680 --> 00:19:18,410 So I talked about embarrassing folks. 403 00:19:18,410 --> 00:19:20,900 Well, let's not let's not embarrass folks right now. 404 00:19:20,900 --> 00:19:23,990 So let's say the pilot and let's say 405 00:19:23,990 --> 00:19:26,330 you're doing some great resource management. 406 00:19:26,330 --> 00:19:28,385 You have another pilot sitting next to you, 407 00:19:28,385 --> 00:19:32,540 so your co-pilot is there, and you also 408 00:19:32,540 --> 00:19:37,220 have some big folks sitting in the back, both the left 409 00:19:37,220 --> 00:19:38,540 and the right side. 410 00:19:38,540 --> 00:19:42,050 And you want to take a bunch of pictures and stuff, 411 00:19:42,050 --> 00:19:44,340 but you want to get as low as you want, 412 00:19:44,340 --> 00:19:46,430 so you put in some bags. 413 00:19:46,430 --> 00:19:49,870 So this-- it's actually hard to see because there's 414 00:19:49,870 --> 00:19:51,040 too much weight. 415 00:19:51,040 --> 00:19:54,970 This red little plus sign is showing 416 00:19:54,970 --> 00:19:57,820 where your center of gravity fell 417 00:19:57,820 --> 00:20:02,560 and whether it's within that utility or normal category. 418 00:20:02,560 --> 00:20:05,660 So in this case, we have three people. 419 00:20:05,660 --> 00:20:08,350 Front two are 200 pounds each, one person 420 00:20:08,350 --> 00:20:13,110 in the rear with 200, and bags there weighing about 10 pounds. 421 00:20:13,110 --> 00:20:16,630 Is this safe to fly? 422 00:20:16,630 --> 00:20:20,560 No, so you're a little red dot went outside the limits. 423 00:20:20,560 --> 00:20:23,470 If you have a much smaller person sitting 424 00:20:23,470 --> 00:20:26,500 in the back seat, you cross over that line, 425 00:20:26,500 --> 00:20:28,960 and now you're back into the normal categories 426 00:20:28,960 --> 00:20:30,490 so you can fly. 427 00:20:30,490 --> 00:20:33,070 Again, another thing you can alter 428 00:20:33,070 --> 00:20:38,870 is, of course, you fill the fuel to tabs. 429 00:20:38,870 --> 00:20:41,010 So this is also talking about-- 430 00:20:41,010 --> 00:20:47,143 so most of the time in the POH book, so the section 6 431 00:20:47,143 --> 00:20:48,310 is about weight and balance. 432 00:20:48,310 --> 00:20:49,820 So although the one example I just 433 00:20:49,820 --> 00:20:53,660 showed you was for a Cessna 172, the Piper Warrior 434 00:20:53,660 --> 00:20:56,210 also has that consistent, so really 435 00:20:56,210 --> 00:21:01,790 recommend just memorizing the table of contents for your POH. 436 00:21:01,790 --> 00:21:05,930 So the way that you go about calculating it 437 00:21:05,930 --> 00:21:08,540 is the same way we entered it into their little calculator. 438 00:21:08,540 --> 00:21:11,870 So first you have to determine the basic empty weight 439 00:21:11,870 --> 00:21:15,110 of the aircraft and then the moment. 440 00:21:15,110 --> 00:21:18,740 Section 6 almost always also has a place for you 441 00:21:18,740 --> 00:21:21,020 to do that calculation, and so they 442 00:21:21,020 --> 00:21:23,240 have a place right there where you 443 00:21:23,240 --> 00:21:26,750 can enter in your airplane, the moment, 444 00:21:26,750 --> 00:21:29,570 and it does the same steps that we just saw on the slide. 445 00:21:29,570 --> 00:21:31,850 So you start with that basic empty weight, 446 00:21:31,850 --> 00:21:35,180 then you focus on the fuel, and it gives you 447 00:21:35,180 --> 00:21:38,330 the 6 pounds per gallon is what you're 448 00:21:38,330 --> 00:21:41,370 going to most likely be using. 449 00:21:41,370 --> 00:21:43,710 What is the max number of gallons? 450 00:21:43,710 --> 00:21:46,440 What is the amount for tabs? 451 00:21:46,440 --> 00:21:49,200 You want to actually look this up for your airplane. 452 00:21:49,200 --> 00:21:51,960 The weight of the pilot in the front passenger, 453 00:21:51,960 --> 00:21:55,320 rear passengers, and the baggage area, and then you 454 00:21:55,320 --> 00:21:57,630 get this ramp weight. 455 00:21:57,630 --> 00:21:59,580 And as I talked about, you can actually 456 00:21:59,580 --> 00:22:02,730 have your plane be a little heavier than the envelope right 457 00:22:02,730 --> 00:22:04,680 when it's fueled on the ramp because there's 458 00:22:04,680 --> 00:22:08,898 some allowance for the fuel that you'll burn off during a taxi, 459 00:22:08,898 --> 00:22:09,940 and so that's right here. 460 00:22:09,940 --> 00:22:13,110 So fuel allowance for engine start, taxi, and run up. 461 00:22:13,110 --> 00:22:16,380 So they took off about eight pounds over there, 462 00:22:16,380 --> 00:22:17,970 and then you can calculate it. 463 00:22:17,970 --> 00:22:20,070 And once you locate the point, then you 464 00:22:20,070 --> 00:22:23,470 go to that diagram right here. 465 00:22:23,470 --> 00:22:25,690 So you go to the weight and the moment, 466 00:22:25,690 --> 00:22:29,698 and you figure out whether or not you're in the safe-- 467 00:22:29,698 --> 00:22:31,240 whether or not you're in the envelope 468 00:22:31,240 --> 00:22:35,760 for that normal category of aircraft. 469 00:22:35,760 --> 00:22:37,980 So what we just went through is the same procedure 470 00:22:37,980 --> 00:22:39,120 that's listed right here. 471 00:22:43,020 --> 00:22:45,900 And so here is it just doing that same example 472 00:22:45,900 --> 00:22:47,810 for a particular Piper Warrior. 473 00:22:47,810 --> 00:22:51,410 So they have the basic empty weight of the aircraft. 474 00:22:51,410 --> 00:22:54,660 Just as a hint, if it's something round like 1,500, 475 00:22:54,660 --> 00:22:57,470 then you probably didn't get the exact accurate amount. 476 00:22:57,470 --> 00:23:00,320 So again, if you look at the real thing, 477 00:23:00,320 --> 00:23:06,160 you're getting it down to some very specific accurate numbers. 478 00:23:06,160 --> 00:23:10,060 So 1,196.63. 479 00:23:10,060 --> 00:23:11,530 That means you got a real number. 480 00:23:14,240 --> 00:23:16,690 Here's our Piper Warrior. 481 00:23:16,690 --> 00:23:20,500 And so they have the basic empty weight, the passengers 482 00:23:20,500 --> 00:23:22,530 in the front and the rear. 483 00:23:22,530 --> 00:23:25,060 They don't have any bags here right now, 484 00:23:25,060 --> 00:23:29,230 and they basically multiplied the weight times the arm. 485 00:23:29,230 --> 00:23:31,930 The arm is really indicated in the book 486 00:23:31,930 --> 00:23:34,510 and in these calculators as to where 487 00:23:34,510 --> 00:23:36,520 the location is of the chair. 488 00:23:36,520 --> 00:23:38,700 Now, of course, the seats slide forward and back, 489 00:23:38,700 --> 00:23:40,950 but they usually don't-- they don't get into that many 490 00:23:40,950 --> 00:23:44,320 specifics, and then you can calculate here the moment. 491 00:23:44,320 --> 00:23:46,660 So next, we do the ramp condition. 492 00:23:46,660 --> 00:23:49,150 So ramp condition is basically, what's 493 00:23:49,150 --> 00:23:51,490 the weight and loading of your airplane 494 00:23:51,490 --> 00:23:53,770 once it's fueled up and sitting on the ramp? 495 00:23:53,770 --> 00:23:55,600 Then you, in this case, they took off 496 00:23:55,600 --> 00:23:58,690 seven pounds for that taxi, and run up 497 00:23:58,690 --> 00:24:01,900 and then you're takeoff condition, in this case, 498 00:24:01,900 --> 00:24:10,420 is 2,440 pounds, and it has a moment here as calculated. 499 00:24:10,420 --> 00:24:12,970 So you basically do the same thing we just showed. 500 00:24:12,970 --> 00:24:15,760 So you you look at the weight on the left, 501 00:24:15,760 --> 00:24:18,370 and the CG location as the vertical line, 502 00:24:18,370 --> 00:24:20,590 and you see where those two lines intersect 503 00:24:20,590 --> 00:24:23,681 and you see whether or not it's inside the envelope. 504 00:24:26,390 --> 00:24:28,640 You can also check the landing condition. 505 00:24:28,640 --> 00:24:33,450 In general, you will have burned fuel during your flight, 506 00:24:33,450 --> 00:24:36,290 and so your landing condition will be lower, 507 00:24:36,290 --> 00:24:39,380 but you might have heard big jets, 508 00:24:39,380 --> 00:24:43,100 and you've heard that sometimes they have to do a fuel dump. 509 00:24:43,100 --> 00:24:44,840 Why did they have to do a fuel dump? 510 00:24:44,840 --> 00:24:47,660 Well, maybe they calculated their landing 511 00:24:47,660 --> 00:24:49,382 based on having flown across the country, 512 00:24:49,382 --> 00:24:50,840 but their flight across the country 513 00:24:50,840 --> 00:24:52,820 was canceled because of weather or whatever, 514 00:24:52,820 --> 00:24:55,787 and so they had to dump their fuel in order to land, 515 00:24:55,787 --> 00:24:58,370 which you don't like to hear is once they've dumped their fuel 516 00:24:58,370 --> 00:25:00,500 then you have another delay in the air, and you're like, hey, 517 00:25:00,500 --> 00:25:01,083 what happened? 518 00:25:01,083 --> 00:25:03,560 I thought we dumped all of our fuel. 519 00:25:03,560 --> 00:25:06,020 But of course, as a small little airplane, 520 00:25:06,020 --> 00:25:08,060 dumping fuel is not really a procedure 521 00:25:08,060 --> 00:25:11,030 you're going to be doing, so it might be a good idea 522 00:25:11,030 --> 00:25:14,750 to just calculate the landing and the runway lengths 523 00:25:14,750 --> 00:25:19,220 with the full fuel in case you have to make it landing right 524 00:25:19,220 --> 00:25:22,010 then and there before you've flown all the distance you 525 00:25:22,010 --> 00:25:25,300 thought you were going to get to fly. 526 00:25:25,300 --> 00:25:30,710 So in general, as you can see that where we were beforehand 527 00:25:30,710 --> 00:25:32,620 was higher and the weight goes down, 528 00:25:32,620 --> 00:25:34,940 so your landing condition is almost always 529 00:25:34,940 --> 00:25:37,710 going to stay within the envelope. 530 00:25:37,710 --> 00:25:40,450 There's some places, where if you're CG 531 00:25:40,450 --> 00:25:42,830 is too far aft or too far forward, 532 00:25:42,830 --> 00:25:44,930 where actually that reduction in weight 533 00:25:44,930 --> 00:25:47,171 could cause you to come outside the envelope. 534 00:25:49,820 --> 00:25:52,530 All right, so there are also a lot of spreadsheets available. 535 00:25:52,530 --> 00:25:55,410 You can make your own spreadsheet pretty quickly 536 00:25:55,410 --> 00:25:58,920 in Excel using the data from the particular aircraft 537 00:25:58,920 --> 00:26:00,420 that you're renting or buying. 538 00:26:03,780 --> 00:26:07,220 All right, and these are just some snapshots 539 00:26:07,220 --> 00:26:09,020 from the book that we just looked at 540 00:26:09,020 --> 00:26:11,540 and the show pictures of where the seats are 541 00:26:11,540 --> 00:26:15,350 in the airplane in order for you to calculate that. 542 00:26:15,350 --> 00:26:19,910 You could also calculate the moment left to right. 543 00:26:19,910 --> 00:26:21,800 It's pretty easy to think about, though, 544 00:26:21,800 --> 00:26:23,750 that in that tiny little airplane, 545 00:26:23,750 --> 00:26:26,287 if you're sitting on the front in the left and no one's 546 00:26:26,287 --> 00:26:28,370 sitting on your right and you have someone sitting 547 00:26:28,370 --> 00:26:31,610 in the back on the left, then you're going to be tilted over. 548 00:26:31,610 --> 00:26:33,370 It's very easy to fix that problem, 549 00:26:33,370 --> 00:26:36,680 just make sure you have someone sitting on the other side. 550 00:26:36,680 --> 00:26:39,540 I have noticed some of these effects before. 551 00:26:39,540 --> 00:26:42,080 I'm a little bit of a smaller person, 552 00:26:42,080 --> 00:26:45,140 and there was a very, very large instructor sitting next to me, 553 00:26:45,140 --> 00:26:47,750 and I actually could tell as I was flying that it 554 00:26:47,750 --> 00:26:49,370 was a little bit tilted. 555 00:26:49,370 --> 00:26:52,100 And so with the future flights, we put some more bags 556 00:26:52,100 --> 00:26:55,250 on my side, and it was a little bit more evened out. 557 00:26:55,250 --> 00:26:58,130 Usually, you won't run into that too much as an issue. 558 00:26:58,130 --> 00:27:02,570 In some of the small puddle jumper aircraft and so 559 00:27:02,570 --> 00:27:06,650 a commercial aircraft, they have sometimes a situation 560 00:27:06,650 --> 00:27:10,322 where there's only one row of seats on one side 561 00:27:10,322 --> 00:27:11,780 and then there's the aisle and then 562 00:27:11,780 --> 00:27:13,407 two seats on the other side. 563 00:27:13,407 --> 00:27:14,990 Have you guys seen that configuration? 564 00:27:14,990 --> 00:27:16,710 I'm getting a lot of head nods. 565 00:27:16,710 --> 00:27:20,270 So in that situation, they might enforce 566 00:27:20,270 --> 00:27:22,940 that you have to sit in the seat that was assigned to you. 567 00:27:22,940 --> 00:27:26,420 And when people try to move from the side that 568 00:27:26,420 --> 00:27:28,787 only had one seat in the row to the side that 569 00:27:28,787 --> 00:27:31,370 has two seats because they just want more space to spread out, 570 00:27:31,370 --> 00:27:33,537 they might say, hey, for weight and balance reasons, 571 00:27:33,537 --> 00:27:37,040 you have to sit in the seat that was assigned for takeoff 572 00:27:37,040 --> 00:27:40,290 and so that's what they're talking about. 573 00:27:40,290 --> 00:27:42,480 There any questions about weight and balance? 574 00:27:51,230 --> 00:27:53,280 Do you guys think you could do weight and balance 575 00:27:53,280 --> 00:27:54,580 calculations? 576 00:27:54,580 --> 00:27:55,080 Yes? 577 00:27:55,080 --> 00:27:57,540 OK, I'm getting a lot of head nods, so everyone took physics. 578 00:27:57,540 --> 00:27:58,040 That's good. 579 00:27:58,040 --> 00:27:58,620 Good job. 580 00:27:58,620 --> 00:27:59,120 Yes? 581 00:27:59,120 --> 00:28:03,129 AUDIENCE: So I assume that [INAUDIBLE] the helicopter has 582 00:28:03,129 --> 00:28:05,524 lateral elements in the chart. 583 00:28:05,524 --> 00:28:08,400 [INAUDIBLE] 584 00:28:08,400 --> 00:28:10,230 TINA SRIVASTAVA: Helicopter question. 585 00:28:10,230 --> 00:28:13,320 I will actually defer to Philip, who flies helicopters 586 00:28:13,320 --> 00:28:14,410 quite frequently. 587 00:28:14,410 --> 00:28:18,300 So once he's back, we'll ask him about helicopter CG limits. 588 00:28:18,300 --> 00:28:20,610 Good question. 589 00:28:20,610 --> 00:28:23,074 Anything else? 590 00:28:23,074 --> 00:28:24,026 Yes? 591 00:28:24,026 --> 00:28:32,730 AUDIENCE: [INAUDIBLE] 592 00:28:32,730 --> 00:28:35,030 TINA SRIVASTAVA: So the question is, 593 00:28:35,030 --> 00:28:36,710 when you're actually flying, do you 594 00:28:36,710 --> 00:28:38,603 do this calculation every single time, 595 00:28:38,603 --> 00:28:40,520 or do you mostly only do it when you're really 596 00:28:40,520 --> 00:28:41,690 loading the aircraft? 597 00:28:41,690 --> 00:28:43,790 So it's actually required that you have 598 00:28:43,790 --> 00:28:45,662 the weight and balance done. 599 00:28:45,662 --> 00:28:47,870 The reason you don't do it every single time, though, 600 00:28:47,870 --> 00:28:50,340 is you frequently fly in the same configuration. 601 00:28:50,340 --> 00:28:52,550 So if you rent from a flight school, 602 00:28:52,550 --> 00:28:55,940 you might frequently rent you know a couple aircraft, 603 00:28:55,940 --> 00:28:59,960 and you might frequently fly just yourself, 604 00:28:59,960 --> 00:29:02,570 doing a solo flight, or fly with your instructor. 605 00:29:02,570 --> 00:29:05,150 So you might just keep it stored that you 606 00:29:05,150 --> 00:29:08,240 have a couple of pieces of paper in your flight bag 607 00:29:08,240 --> 00:29:11,000 that are the weight and balance calculations for what you 608 00:29:11,000 --> 00:29:13,520 almost always fly and is almost always 609 00:29:13,520 --> 00:29:16,580 within the normal category envelope. 610 00:29:16,580 --> 00:29:19,670 But you definitely want to do those calculations 611 00:29:19,670 --> 00:29:22,460 if you're getting passengers in the back seat. 612 00:29:22,460 --> 00:29:24,890 Whenever we go on these MIT fly outs, 613 00:29:24,890 --> 00:29:28,080 we actually ask people for their weights, 614 00:29:28,080 --> 00:29:31,070 and it's actually a big restriction too. 615 00:29:31,070 --> 00:29:33,443 So when we're trying to get passengers to sit down, 616 00:29:33,443 --> 00:29:35,360 just because I fly assessment with four seats, 617 00:29:35,360 --> 00:29:38,980 as we just saw from the example, I don't have four pass-- 618 00:29:38,980 --> 00:29:40,810 I don't have three passengers to offer. 619 00:29:40,810 --> 00:29:44,690 I often say, I have 220 pounds available, 620 00:29:44,690 --> 00:29:49,160 and so they then have to sort out, Sebastian and his team, 621 00:29:49,160 --> 00:29:52,963 as to who to assign to my plane versus another plane. 622 00:29:52,963 --> 00:29:54,380 And also, if people aren't being-- 623 00:29:54,380 --> 00:29:56,743 if you notice people aren't being overly forthcoming 624 00:29:56,743 --> 00:29:58,160 about their weight, you might want 625 00:29:58,160 --> 00:30:00,440 to increase the amount that they gave you. 626 00:30:00,440 --> 00:30:02,870 PHILIP GREENSPUN: Yeah, let me add that-- 627 00:30:02,870 --> 00:30:05,180 obviously, have a lot more experience 628 00:30:05,180 --> 00:30:12,222 being over overweight than Tina might have, but also-- 629 00:30:12,222 --> 00:30:13,930 actually, these pants are a good example. 630 00:30:13,930 --> 00:30:17,060 20 years ago, some friends and I, 631 00:30:17,060 --> 00:30:20,120 we made a web front end to a Levi Strauss factory that 632 00:30:20,120 --> 00:30:22,130 could make custom cut khakis. 633 00:30:22,130 --> 00:30:23,660 So we asked people in the web form 634 00:30:23,660 --> 00:30:25,820 when they ordered what's your waist size, what's 635 00:30:25,820 --> 00:30:28,520 your inseam, what's your height and weight. 636 00:30:28,520 --> 00:30:32,000 And from that, we had software to try 637 00:30:32,000 --> 00:30:35,287 to infer their actual weight, their actual waist size, 638 00:30:35,287 --> 00:30:37,370 and then we make them-- you can't really see this, 639 00:30:37,370 --> 00:30:39,790 but these pants just say pair number 7. 640 00:30:39,790 --> 00:30:42,490 They don't say anything about what size it actually is. 641 00:30:42,490 --> 00:30:43,820 They would get their pants-- 642 00:30:43,820 --> 00:30:45,660 this was in 1997. 643 00:30:45,660 --> 00:30:47,720 They would get their pants, if they didn't fit, 644 00:30:47,720 --> 00:30:50,303 they'd say, look, it needs to be a little looser in the waist. 645 00:30:50,303 --> 00:30:52,370 It needs to be a little shorter, and then 646 00:30:52,370 --> 00:30:55,520 a revised pair would be made and sent to them, 647 00:30:55,520 --> 00:30:58,130 but we never relied on their stated weight 648 00:30:58,130 --> 00:31:00,872 or their stated waist size, exactly. 649 00:31:00,872 --> 00:31:03,080 TINA SRIVASTAVA: Philip, there was a question for you 650 00:31:03,080 --> 00:31:06,950 that I wasn't able to answer about helicopter CGs, 651 00:31:06,950 --> 00:31:09,210 and really thinking it was the lateral CG. 652 00:31:09,210 --> 00:31:10,710 What was your question specifically? 653 00:31:10,710 --> 00:31:13,230 AUDIENCE: [INAUDIBLE] 654 00:31:13,230 --> 00:31:16,250 PHILIP GREENSPUN: It's very hard to get a-- the question is 655 00:31:16,250 --> 00:31:19,240 it's very hard to get a helicopter out of lateral CG, 656 00:31:19,240 --> 00:31:20,230 as with an aircraft. 657 00:31:20,230 --> 00:31:23,350 If you have to have you people in the back and a light person 658 00:31:23,350 --> 00:31:29,700 in the front, it's easy to get out of front back CG, 659 00:31:29,700 --> 00:31:32,160 longitudinal CG, but-- 660 00:31:32,160 --> 00:31:34,660 TINA SRIVASTAVA: He's talking about, what we just discussed, 661 00:31:34,660 --> 00:31:36,493 it's frequently the case that you might have 662 00:31:36,493 --> 00:31:39,490 a forward CG or an aft CG, but you don't usually 663 00:31:39,490 --> 00:31:43,810 have an issue with the CG on the left or the right, unless-- 664 00:31:43,810 --> 00:31:47,090 it's very visible in a four seat aircraft 665 00:31:47,090 --> 00:31:48,548 how to fix those types of problems. 666 00:31:48,548 --> 00:31:50,423 PHILIP GREENSPUN: One issue with the Robinson 667 00:31:50,423 --> 00:31:52,510 is they put the main fuel tank on the left, 668 00:31:52,510 --> 00:31:53,970 so they're budgeting for-- 669 00:31:53,970 --> 00:31:57,490 in a solo situation, a pilot of at least a certain minimum 670 00:31:57,490 --> 00:31:59,440 weight in the front right. 671 00:31:59,440 --> 00:32:02,320 So very lightweight, sometimes when 672 00:32:02,320 --> 00:32:04,630 teenagers are learning to fly helicopters, 673 00:32:04,630 --> 00:32:06,790 they have to add a little bit of ballast, 674 00:32:06,790 --> 00:32:10,240 let's say like a big heavy gym weight. 675 00:32:10,240 --> 00:32:13,810 A 50 pound gym weight in the front 676 00:32:13,810 --> 00:32:15,790 left footwell or something. 677 00:32:15,790 --> 00:32:18,640 AUDIENCE: The other thing that could go wrong is-- 678 00:32:18,640 --> 00:32:21,850 so when you do your pre-flight, one of the things that you do 679 00:32:21,850 --> 00:32:24,890 is that if you're sitting in the pilot's seat, so 680 00:32:24,890 --> 00:32:27,040 on the left side, so to your right 681 00:32:27,040 --> 00:32:28,810 in the middle at the bottom, there's 682 00:32:28,810 --> 00:32:31,300 a little knob where you can say whether you want 683 00:32:31,300 --> 00:32:34,990 the fuel to be coming from the left tank, the right tank, 684 00:32:34,990 --> 00:32:35,860 or both. 685 00:32:35,860 --> 00:32:38,830 And pretty much, all the time, the checklist 686 00:32:38,830 --> 00:32:40,663 says that after you've parked the plane, 687 00:32:40,663 --> 00:32:42,580 you want to twist it to the left or the right, 688 00:32:42,580 --> 00:32:44,110 and the reason is you don't want-- 689 00:32:44,110 --> 00:32:45,850 while it's sitting there, fuel to be 690 00:32:45,850 --> 00:32:49,960 sloshing across the plane, and so you set it to left, 691 00:32:49,960 --> 00:32:51,020 for example. 692 00:32:51,020 --> 00:32:53,590 Now, if you skipped that step, even though it comes up 693 00:32:53,590 --> 00:32:56,020 several times throughout your pre-flight 694 00:32:56,020 --> 00:33:00,160 and then your run up check, if you didn't put the fuel 695 00:33:00,160 --> 00:33:03,430 to draw from both tanks and it's only drawing from one tank, 696 00:33:03,430 --> 00:33:07,598 then you might experience that instability. 697 00:33:07,598 --> 00:33:09,390 PHILIP GREENSPUN: All right, why don't we-- 698 00:33:09,390 --> 00:33:12,280 should we take a 15-minute break so people can run out, 699 00:33:12,280 --> 00:33:14,890 grab food, bring it back, and then we'll hear from 700 00:33:14,890 --> 00:33:16,150 [INAUDIBLE] about-- 701 00:33:16,150 --> 00:33:19,870 TINA SRIVASTAVA: The test pilot and life potentially outside 702 00:33:19,870 --> 00:33:21,570 of the limits.