WEBVTT 00:12.325 --> 00:15.492 (inspirational music) 00:19.990 --> 00:21.980 - Right now you're probably sitting in math class 00:21.980 --> 00:25.080 thinking "I'm never going to use this math stuff. 00:25.080 --> 00:26.840 Why do I even have to learn how to add, 00:26.840 --> 00:30.020 use equations, determine what this X and Y are?" 00:30.020 --> 00:32.800 I have been in your shoes and I have felt the same way. 00:32.800 --> 00:35.300 Hello I'm United States Air Force 00:35.300 --> 00:38.947 Technical Sergeant Joe Timpson, a C-17 Loadmaster 00:38.947 --> 00:40.000 in the 6th Airlift Squadron 00:40.000 --> 00:42.630 here at Joint Base McGuire-Dix-Lakehurst New Jersey, 00:42.630 --> 00:44.364 And I will show you today 00:44.364 --> 00:46.152 how I use the math I learned in school 00:46.152 --> 00:47.547 to apply it to my job. 00:47.547 --> 00:50.714 (inspirational music) 00:55.717 --> 00:57.730 So how do we balance a big cargo plane? 00:57.730 --> 00:59.520 Well, first we have to determine the weight and balance 00:59.520 --> 01:01.470 of the vehicle or the cargo we receive. 01:11.760 --> 01:15.040 So behind me, I have a vehicle that we commonly would load. 01:15.040 --> 01:17.150 My first job is to figure out the gross weight 01:17.150 --> 01:19.810 of that vehicle to figure out how to balance it out. 01:19.810 --> 01:21.510 I will take the front axle weight, 01:22.962 --> 01:24.712 and add it to the rear axle weight. 01:26.570 --> 01:27.420 The principle way I find that out 01:27.420 --> 01:28.640 by taking two portable scales 01:28.640 --> 01:30.330 and place it in front of the vehicle. 01:30.330 --> 01:31.430 Drive the vehicle up, 01:31.430 --> 01:32.950 we'll get a weight on each tire, 01:32.950 --> 01:35.090 and together I'll have the front axle weight, 01:35.090 --> 01:36.890 I'll repeat the process for the rear tires, 01:36.890 --> 01:38.390 and have the rear axle weight. 01:39.401 --> 01:40.640 Add those numbers together 01:40.640 --> 01:43.033 and I will have my gross weight of the entire vehicle. 01:51.240 --> 01:52.220 The next step is to find 01:52.220 --> 01:54.320 the center of gravity for the vehicle. 01:54.320 --> 01:56.120 We already have part of this problem done 01:56.120 --> 01:57.490 when we weighed the vehicle. 01:57.490 --> 01:58.370 Now we have to measure 01:58.370 --> 02:00.250 what is called the vehicle's wheelbase. 02:00.250 --> 02:02.780 Once we get that, we measure the center of the forward wheel 02:02.780 --> 02:04.380 to the center of the rear wheel. 02:06.700 --> 02:09.500 Once we have that number, we multiply the rear axle weight 02:09.500 --> 02:12.000 with the wheelbase to get what we call the moment. 02:15.080 --> 02:17.240 We then divide the moment by the gross weight 02:17.240 --> 02:21.430 to determine our vehicle CG or center of gravity in inches 02:21.430 --> 02:23.080 after the front axle. 02:23.080 --> 02:24.270 I round that up to 65, 02:24.270 --> 02:26.010 that tells me that my center of balance 02:26.010 --> 02:29.260 is 65 inches from the front axle of my vehicle. 02:29.260 --> 02:32.410 So why do we need to know the center of balance of my cargo? 02:32.410 --> 02:34.490 Well, I need to have properly marked cargo 02:34.490 --> 02:37.450 to make sure I have a good center bounce in my aircraft. 02:37.450 --> 02:39.480 Otherwise if my weight balance is off, 02:39.480 --> 02:41.918 there's a potential for a disaster to occur. 02:41.918 --> 02:44.930 (cargo crashing) 02:44.930 --> 02:46.460 Now that I showed you guys how to find 02:46.460 --> 02:47.610 the center of balance of a vehicle, 02:47.610 --> 02:49.640 let's show you how we put that on an aircraft 02:49.640 --> 02:51.840 to ensure we have a smooth and safe takeoff. 02:54.680 --> 02:57.410 Our goal is to align the center of balance of that vehicle 02:57.410 --> 02:58.610 with one of our station numbers 02:58.610 --> 03:00.150 in the front of our aircraft. 03:00.150 --> 03:03.330 We're shooting for station number 500 right now. 03:03.330 --> 03:06.340 Our aircraft is much with center of balance station numbers 03:06.340 --> 03:08.900 or CB station number for short. 03:08.900 --> 03:11.007 They are marked on both sides of the aircraft 03:11.007 --> 03:13.010 and the inside on the upper portion 03:13.010 --> 03:15.210 and lower portion of our aircraft. 03:15.210 --> 03:16.790 They are measured in inches 03:16.790 --> 03:19.100 from the very front of our aircraft. 03:19.100 --> 03:23.540 So you recall our vehicle weighs 8,220 pounds. 03:23.540 --> 03:27.970 It is now sitting at CB station number 500, 03:27.970 --> 03:30.940 and you multiply that vehicle weight times station number, 03:30.940 --> 03:35.350 you'll get 4,110,000 moments. 03:35.350 --> 03:36.640 With an aircraft this large, 03:36.640 --> 03:38.920 we do not want to waste the space we have available. 03:38.920 --> 03:41.280 Therefore we wouldn't fly this entire aircraft around 03:41.280 --> 03:43.250 with only one vehicle on board. 03:43.250 --> 03:45.340 So I've already gone ahead and calculated 03:45.340 --> 03:47.400 the center of gravity and the gross weights 03:47.400 --> 03:48.883 for two more vehicles. 03:53.536 --> 03:56.420 So now we've loaded all of our cargo onto our aircraft. 03:56.420 --> 03:57.680 Our total load weight, 03:57.680 --> 04:00.140 again, that's the weight of all the vehicles loaded 04:00.140 --> 04:03.520 is 38,607 pounds. 04:03.520 --> 04:06.603 Our total moments total up as well as 29,836,380 moments. 04:10.503 --> 04:12.980 I divide the total moments, divide by total weight, 04:12.980 --> 04:15.720 and I get a CV station of 773. 04:15.720 --> 04:19.980 What that means is 773 inches from the front of my aircraft 04:19.980 --> 04:21.600 is where it is balanced. 04:21.600 --> 04:23.050 Now we are ready to fly safe.