1 00:00:00,000 --> 00:00:04,000 Hi, I'm John Delfrate. You guys are the Treehouse Detectives. 2 00:00:04,000 --> 00:00:07,000 That's us. Thanks for talking with us. 3 00:00:07,000 --> 00:00:09,000 What can I help you with today? 4 00:00:09,000 --> 00:00:11,000 We're having a hard time with testing. 5 00:00:11,000 --> 00:00:13,000 We heard you just finished testing the Helios plane. 6 00:00:13,000 --> 00:00:15,000 Could you give us some advice on testing? 7 00:00:15,000 --> 00:00:17,000 Sure, I'd be happy to. 8 00:00:17,000 --> 00:00:19,000 What exactly is the Helios? 9 00:00:19,000 --> 00:00:23,000 Well, Helios is a solar-powered flying wing aircraft. 10 00:00:23,000 --> 00:00:25,000 It's flown remotely from the ground, 11 00:00:25,000 --> 00:00:28,000 and some people have described it as a flying yardstick. 12 00:00:28,000 --> 00:00:31,000 It's not designed to carry people, so you can shape it much differently. 13 00:00:31,000 --> 00:00:34,000 It has one of the biggest wings ever built. 14 00:00:34,000 --> 00:00:37,000 If you can believe it, its wingspan is bigger than a 747's. 15 00:00:37,000 --> 00:00:41,000 Yet it's extremely lightweight. It weighs less than most cars. 16 00:00:41,000 --> 00:00:43,000 Why was it built? 17 00:00:43,000 --> 00:00:45,000 NASA had two reasons. 18 00:00:45,000 --> 00:00:48,000 The first was that we needed a special airplane 19 00:00:48,000 --> 00:00:52,000 to collect information about our atmosphere up to 100,000 feet. 20 00:00:52,000 --> 00:00:56,000 That's three times higher than a regular passenger airplane flies. 21 00:00:56,000 --> 00:01:03,000 Recently, Helios set a new world record by flying to 96,863 feet. 22 00:01:03,000 --> 00:01:06,000 The second reason was that we wanted to design an airplane 23 00:01:06,000 --> 00:01:09,000 to fly longer than any airplane has ever flown. 24 00:01:09,000 --> 00:01:11,000 Why do you need to test your vision? 25 00:01:11,000 --> 00:01:14,000 Could you tell us how you tested the Helios plane? 26 00:01:14,000 --> 00:01:17,000 Testing is really important for us for a couple different reasons. 27 00:01:17,000 --> 00:01:20,000 The first is that we want to make sure we actually understand 28 00:01:20,000 --> 00:01:23,000 how our airplane and its parts work. 29 00:01:23,000 --> 00:01:27,000 We design a test and use the best information to predict the outcome of it. 30 00:01:27,000 --> 00:01:30,000 Then we compare the results with our predictions 31 00:01:30,000 --> 00:01:32,000 and figure out why they might be different. 32 00:01:32,000 --> 00:01:34,000 There's another reason why we test so much. 33 00:01:34,000 --> 00:01:37,000 It's because building airplanes is very expensive. 34 00:01:37,000 --> 00:01:41,000 We've been testing different parts of Helios since 1996. 35 00:01:41,000 --> 00:01:44,000 That's a long time. How could it take that long? 36 00:01:44,000 --> 00:01:48,000 In the beginning, we started out with simple models like this one 37 00:01:48,000 --> 00:01:50,000 to test the aerodynamic design. 38 00:01:50,000 --> 00:01:53,000 And then we made bigger and more complicated models 39 00:01:53,000 --> 00:01:56,000 until we were ready to actually make the real airplane. 40 00:01:56,000 --> 00:01:59,000 On some of our parts, like the propellers for example, 41 00:01:59,000 --> 00:02:02,000 we had to change the design and start all over. 42 00:02:02,000 --> 00:02:04,000 It's a long process. 43 00:02:04,000 --> 00:02:06,000 We aren't the only ones who've taken time to test. 44 00:02:06,000 --> 00:02:09,000 The Wright Brothers tested patiently for several years 45 00:02:09,000 --> 00:02:12,000 before they succeeded way back in 1903. 46 00:02:12,000 --> 00:02:14,000 Careful testing leads to success. 47 00:02:14,000 --> 00:02:18,000 By the way, you know the place where the Wright Brothers completed their first flight? 48 00:02:18,000 --> 00:02:21,000 It's a national monument, and it's a wonderful place to visit. 49 00:02:21,000 --> 00:02:23,000 Great idea. We should go there. 50 00:02:23,000 --> 00:02:25,000 Do you have any other advice for us in our invention? 51 00:02:25,000 --> 00:02:27,000 Actually, I do. 52 00:02:27,000 --> 00:02:30,000 Before you begin the test, you need to think about 53 00:02:30,000 --> 00:02:33,000 what could possibly go wrong and be prepared to handle it. 54 00:02:33,000 --> 00:02:36,000 Thank you, and good luck with Helios.