WEBVTT 00:00:00.000 --> 00:00:04.139 If you told a home builder that you wanted a 00:00:04.139 --> 00:00:06.540 house, but you wanted the entire roof to just 00:00:06.540 --> 00:00:09.199 be completely removable at the push of a button, 00:00:09.640 --> 00:00:10.859 I mean, they'd probably look at you like you 00:00:10.859 --> 00:00:12.560 were out of your mind. Oh yeah, they'd tell you 00:00:12.560 --> 00:00:14.679 the walls would simply fold inward, you know, 00:00:14.759 --> 00:00:16.640 the second the strong wind blew or the foundation 00:00:16.640 --> 00:00:18.839 settled. Right. Because the roof is a critical 00:00:18.839 --> 00:00:21.359 structural truss. It's not just there for the 00:00:21.359 --> 00:00:23.879 rain. But when it comes to cars, we've spent 00:00:23.879 --> 00:00:26.140 well over a century obsessing over how to do 00:00:26.140 --> 00:00:29.940 exactly that. We really have. So today we are 00:00:29.940 --> 00:00:33.700 taking a deep dive into the fascinating evolution, 00:00:34.340 --> 00:00:38.280 the wildly complex engineering and the cultural 00:00:38.280 --> 00:00:40.700 history of the convertible car. It's a huge topic. 00:00:40.810 --> 00:00:44.170 It is. And we're using a highly comprehensive 00:00:44.170 --> 00:00:46.929 Wikipedia article on convertibles as our primary 00:00:46.929 --> 00:00:49.030 source today. And our mission for you listening 00:00:49.030 --> 00:00:51.850 is to unpack how taking the roof off a car isn't 00:00:51.850 --> 00:00:54.590 just like a breezy styling choice. Not at all. 00:00:54.770 --> 00:00:57.590 It is a massive engineering nightmare, one that's 00:00:57.590 --> 00:01:01.009 gone through some huge historical booms and busts. 00:01:01.009 --> 00:01:03.350 We're going to get into how engineers solve those 00:01:03.350 --> 00:01:07.189 physics problems and even talk about how the 00:01:07.189 --> 00:01:10.719 Smithsonian Institution completely snubbed the 00:01:10.719 --> 00:01:13.180 quote unquote last American convertible. Which 00:01:13.180 --> 00:01:15.819 is such a great story because for this deep dive 00:01:15.819 --> 00:01:17.560 we aren't just looking at what a convertible 00:01:17.560 --> 00:01:20.280 is we're really dissecting why we go to such 00:01:20.280 --> 00:01:23.329 ridiculous Basically, physics -defying lengths 00:01:23.329 --> 00:01:25.530 to build them. Exactly. And how the mechanics 00:01:25.530 --> 00:01:27.810 of these cars reflect the eras they were actually 00:01:27.810 --> 00:01:30.689 built in. OK, so let's unpack this. Before we 00:01:30.689 --> 00:01:32.670 get into the wild history, we really have to 00:01:32.670 --> 00:01:34.810 understand the fundamental mechanical problem 00:01:34.810 --> 00:01:37.170 of a convertible. Right, the core issue. Because 00:01:37.170 --> 00:01:39.730 it's that specific problem that drives literally 00:01:39.730 --> 00:01:41.689 every technological shift we're going to talk 00:01:41.689 --> 00:01:44.390 about today. But first off, just navigating the 00:01:44.390 --> 00:01:47.340 terminology. is a journey. Oh, it's a total mess. 00:01:47.840 --> 00:01:49.799 The word convertible itself is pretty universal 00:01:49.799 --> 00:01:53.200 now, but you'll constantly see the term cabriolet 00:01:53.200 --> 00:01:55.159 used interchangeably. Which actually comes from 00:01:55.159 --> 00:01:56.859 a horse -drawn carriage, right? Yeah, exactly. 00:01:57.260 --> 00:01:59.680 Looking at the source, a cabriolet was originally 00:01:59.680 --> 00:02:02.060 a light two -wheeled one -horse carriage that 00:02:02.060 --> 00:02:05.200 had a folding top. It was meant to seat two people. 00:02:05.420 --> 00:02:08.860 But automakers over the years have thrown like 00:02:08.860 --> 00:02:10.879 every name in the book at this concept to make 00:02:10.879 --> 00:02:13.020 it sound exotic. Oh, they love the marketing. 00:02:13.120 --> 00:02:15.680 You've got drop -top, rag -top, open two -seater. 00:02:16.199 --> 00:02:18.639 In the UK, the historical term for a two -door 00:02:18.639 --> 00:02:21.300 convertible was a drop -head coupe. Such a fancy 00:02:21.300 --> 00:02:24.080 term. Right. And a four -door was an all -weather 00:02:24.080 --> 00:02:27.860 tourer. You'll also hear spider or spider. And 00:02:27.860 --> 00:02:29.740 what's fascinating here is that the reason there 00:02:29.740 --> 00:02:31.680 are so many names isn't just marketing vanity. 00:02:32.449 --> 00:02:35.090 automakers were constantly trying to brand their 00:02:35.090 --> 00:02:38.289 specific mechanical solutions to one massive 00:02:38.289 --> 00:02:41.090 drawback. Which is? Taking the roof off drastically 00:02:41.090 --> 00:02:43.969 reduces a car's structural rigidity. Okay, let's 00:02:43.969 --> 00:02:45.710 visualize this for you guys listening. Taking 00:02:45.710 --> 00:02:48.789 the roof off a car is essentially like taking 00:02:48.789 --> 00:02:51.150 the lid off a shoe box. I love that analogy. 00:02:51.590 --> 00:02:54.150 If you have a closed shoe box, it's pretty stiff, 00:02:54.330 --> 00:02:57.009 right? Yeah. You can't easily twist it, but the 00:02:57.009 --> 00:02:59.909 second you take the lid off, the whole box suddenly 00:02:59.909 --> 00:03:03.860 becomes twisty, wobbly, and just a lot less stable. 00:03:03.939 --> 00:03:06.500 You can easily bend it diagonally. That is the 00:03:06.500 --> 00:03:09.539 perfect way to picture torsional rigidity. In 00:03:09.539 --> 00:03:13.159 a closed roof car, the body acts as a complete 00:03:13.159 --> 00:03:16.219 unit, like a space frame. The roof is actually 00:03:16.219 --> 00:03:18.599 in compression or tension, depending on how the 00:03:18.599 --> 00:03:20.919 car is moving. So when you hit a plot hole or, 00:03:20.919 --> 00:03:23.680 you know, take a hard corner, the force is distributed 00:03:23.680 --> 00:03:25.780 through the pillars and across the roof. So it 00:03:25.780 --> 00:03:28.650 shares the load. Exactly. remove the roof, and 00:03:28.650 --> 00:03:30.710 all that twisting force goes straight into the 00:03:30.710 --> 00:03:33.090 floor pan. Which means the car physically bends. 00:03:33.250 --> 00:03:35.610 It bends. It twists. You get what engineers call 00:03:35.610 --> 00:03:38.349 cowl shake, where the dashboard visibly vibrates 00:03:38.349 --> 00:03:40.930 independently of the seats. Wow. And your suspension 00:03:40.930 --> 00:03:42.889 geometry goes completely out of whack because 00:03:42.889 --> 00:03:44.689 the mounting points are physically moving away 00:03:44.689 --> 00:03:47.169 from each other. That sounds terrifying. So early 00:03:47.169 --> 00:03:49.389 automakers were dealing with this lidless shoe 00:03:49.389 --> 00:03:51.590 box. Though, to be fair, in the late 19th century, 00:03:51.870 --> 00:03:53.849 most early cars were completely open -air vehicles 00:03:53.849 --> 00:03:56.139 anyway. Right, they were basically just motorized 00:03:56.139 --> 00:03:58.120 benches. Yeah, they didn't have roofs or sides 00:03:58.120 --> 00:04:00.000 at all. Weather protection was definitely an 00:04:00.000 --> 00:04:02.939 afterthought. It was. But as engines got more 00:04:02.939 --> 00:04:05.979 powerful and cars got faster, drivers realized 00:04:05.979 --> 00:04:08.379 they needed some protection from the wind and 00:04:08.379 --> 00:04:10.840 the flying debris. Which makes sense. So they 00:04:10.840 --> 00:04:13.580 started borrowing folding textile or leather 00:04:13.580 --> 00:04:16.500 roofs from older Victoria or Landau carriages. 00:04:16.699 --> 00:04:19.139 You'd see Faitons, which were two seat cars with 00:04:19.139 --> 00:04:23.120 temporary roofs or Landois. What's a Landois? 00:04:23.339 --> 00:04:25.339 That's where the driver sat out in the open, 00:04:25.560 --> 00:04:27.860 but the rear passengers actually had a folding 00:04:27.860 --> 00:04:30.480 roof over them. Oh, interesting. But the less 00:04:30.480 --> 00:04:32.740 expensive cars, like runabouts and the sturdy 00:04:32.740 --> 00:04:35.579 touring cars, they either stayed completely open 00:04:35.579 --> 00:04:38.600 to the air or they just had a really rudimentary 00:04:38.600 --> 00:04:40.939 folding top. Yeah. And maybe some clear side 00:04:40.939 --> 00:04:43.000 curtains you could detach. Right. It wasn't a 00:04:43.000 --> 00:04:45.079 sealed environment by any stretch. Right. Which 00:04:45.079 --> 00:04:48.000 makes the 1920s a massive turning point because 00:04:48.000 --> 00:04:49.939 the source points out that this is when steel 00:04:49.939 --> 00:04:53.920 bodies began to be mass -produced. Yes. The transition 00:04:53.920 --> 00:04:57.699 to the enclosed steel box. Stamping large pieces 00:04:57.699 --> 00:05:01.060 of steel became economically viable. Huge shift. 00:05:01.339 --> 00:05:04.139 Suddenly closed cars became affordable and available 00:05:04.139 --> 00:05:06.560 to the average buyer. You didn't have to freeze 00:05:06.560 --> 00:05:08.420 or get soaked in the rain anymore. And you gained 00:05:08.420 --> 00:05:10.300 all that structural rigidity from our shoebox 00:05:10.300 --> 00:05:12.779 analogy. Exactly. You finally had a lid. Because 00:05:12.779 --> 00:05:15.639 of that, fully open cars almost disappeared from 00:05:15.639 --> 00:05:18.560 the mainstream market. I mean, by the mid -1930s, 00:05:18.759 --> 00:05:21.740 the only convertibles really left were high -priced 00:05:21.740 --> 00:05:24.459 luxury models. They became a status symbol. Yeah, 00:05:24.699 --> 00:05:26.899 and the technology to open the roof was getting 00:05:26.899 --> 00:05:30.800 wildly complex. In 1939, Plymouth introduced 00:05:30.800 --> 00:05:33.560 the first mechanically operated convertible roof. 00:05:34.000 --> 00:05:36.519 And the way they powered it honestly blew my 00:05:36.519 --> 00:05:40.319 mind. Oh, the vacuum cylinders. Yes. Two vacuum 00:05:40.319 --> 00:05:43.639 cylinders. But wait, how does engine vacuum actually 00:05:43.639 --> 00:05:46.379 lift a heavy canvas and metal roof? That sounds 00:05:46.379 --> 00:05:48.100 like trying to suck a bowling ball up through 00:05:48.100 --> 00:05:50.600 a straw. It does sound impossible, right? But 00:05:50.600 --> 00:05:53.360 it's all about surface area and pressure differentials. 00:05:53.920 --> 00:05:56.100 The system harnessed the negative pressure generated 00:05:56.100 --> 00:05:59.000 by the engine's intake manifold. OK, so the engine 00:05:59.000 --> 00:06:02.139 breathing. Exactly. When an engine's pistons 00:06:02.139 --> 00:06:05.899 pull air in, they create a vacuum. Plymouth engineers 00:06:05.899 --> 00:06:09.420 routed that vacuum pressure to two really large 00:06:09.420 --> 00:06:12.779 cylinders mounted behind the rear seats. By manipulating 00:06:12.779 --> 00:06:15.540 valves, that negative pressure would pull large 00:06:15.540 --> 00:06:18.420 pistons inside the cylinders down. And those 00:06:18.420 --> 00:06:20.319 pistons were mechanically linked to the roof 00:06:20.319 --> 00:06:22.579 frame, so it literally hoisted up or pull it 00:06:22.579 --> 00:06:25.360 back. That is absolutely brilliant for 1939. 00:06:26.160 --> 00:06:28.079 But still, the open -air car was essentially 00:06:28.079 --> 00:06:30.480 an endangered species at that point. It was just 00:06:30.480 --> 00:06:33.459 a luxury novelty. Right. Until a massive historical 00:06:33.459 --> 00:06:35.939 event completely shifted the trajectory. And 00:06:35.939 --> 00:06:38.620 that was World War II. Specifically, the experiences 00:06:38.620 --> 00:06:40.879 of American soldiers stationed in France and 00:06:40.879 --> 00:06:43.220 the United Kingdom. Oh, right. While they were 00:06:43.220 --> 00:06:45.980 there, they were exposed to small, really nimble 00:06:45.980 --> 00:06:49.490 European roadsters. cars like the MG Midget and 00:06:49.490 --> 00:06:52.230 the Triumph Roadster. So, wait, it wasn't an 00:06:52.230 --> 00:06:54.110 engineering breakthrough that saved the convertible. 00:06:54.209 --> 00:06:57.350 It was essentially a massive, unintended study 00:06:57.350 --> 00:07:00.029 abroad program for American drivers. That is 00:07:00.029 --> 00:07:02.649 a great way to put it. They drove these lightweight, 00:07:02.970 --> 00:07:06.110 open -air British cars, realized how visceral 00:07:06.110 --> 00:07:08.509 and fun driving could be without a steel roof, 00:07:09.029 --> 00:07:11.689 and created a whole new market demand back home. 00:07:11.879 --> 00:07:14.220 It really proves that automotive trends are often 00:07:14.220 --> 00:07:16.980 driven by massive societal shifts and cultural 00:07:16.980 --> 00:07:19.439 cross -pollination. Yeah. These soldiers came 00:07:19.439 --> 00:07:22.100 back, they wanted that visceral open -air thrill 00:07:22.100 --> 00:07:24.759 they had in Europe, and American automakers scrambled 00:07:24.759 --> 00:07:26.779 to capture that market share. And they went all 00:07:26.779 --> 00:07:29.560 in. I mean, in 1948, Hudson incorporated the 00:07:29.560 --> 00:07:32.100 convertible design into a mass -market unibody. 00:07:32.579 --> 00:07:34.680 But hold on, if we go back to our shoebox analogy, 00:07:35.199 --> 00:07:38.160 a unibody means the frame and the body are one 00:07:38.160 --> 00:07:40.560 single piece. Correct. If you chop the roof off 00:07:40.560 --> 00:07:43.120 a unibody, Doesn't that make the structural problem 00:07:43.120 --> 00:07:45.939 infinitely worse than an older body -on -frame 00:07:45.939 --> 00:07:48.399 car? It really does, which is why engineering 00:07:48.399 --> 00:07:51.360 a unibody convertible is notoriously difficult. 00:07:51.959 --> 00:07:54.300 Hudson and the automakers that followed, they 00:07:54.300 --> 00:07:56.540 had to massively reinforce the floor pan. Just 00:07:56.540 --> 00:07:58.980 to compensate for the missing roof. Exactly. 00:07:59.180 --> 00:08:01.600 Yeah. They had to weld thick steel cross members 00:08:01.600 --> 00:08:04.879 under the car, add heavier rocker panels, and 00:08:04.879 --> 00:08:07.319 beef up the transmission tunnel just to claw 00:08:07.319 --> 00:08:09.860 back a fraction of the rigidity they lost. That 00:08:09.860 --> 00:08:12.759 sounds heavy. Very heavy. This is why convertibles 00:08:12.759 --> 00:08:14.899 are almost always significantly heavier than 00:08:14.899 --> 00:08:17.139 their hardtop counterparts. You're carrying around 00:08:17.139 --> 00:08:19.180 all this hidden steel just to keep the car from 00:08:19.180 --> 00:08:22.399 folding in half. But despite the weight, It kicked 00:08:22.399 --> 00:08:25.920 off a golden age in the 1950s and 60s. The quintessential 00:08:25.920 --> 00:08:28.779 American cruiser era. Right. You had economical 00:08:28.779 --> 00:08:31.639 compacts like the Rambler American and the Studebaker 00:08:31.639 --> 00:08:34.639 Lark, all the way up to these massive, heavy 00:08:34.639 --> 00:08:36.860 luxury boats like the Packard Caribbean, the 00:08:36.860 --> 00:08:41.019 Oldsmobile 98, and the Imperial by Chrysler. 00:08:41.139 --> 00:08:43.440 It seemed like every automaker just automatically 00:08:43.440 --> 00:08:45.360 included a convertible option in their lineup. 00:08:45.519 --> 00:08:48.299 It was the absolute height of post -war automotive 00:08:48.299 --> 00:08:51.179 optimism. Totally. But the source data showed 00:08:51.120 --> 00:08:53.480 There was a fascinating pivot here. Following 00:08:53.480 --> 00:08:55.960 that boom, human innovation actually started 00:08:55.960 --> 00:08:58.200 working against the convertible. Yeah, the market 00:08:58.200 --> 00:09:00.940 forces shifted drastically. Right, because convertible 00:09:00.940 --> 00:09:04.860 sales in the U .S. peaked around 1965. But over 00:09:04.860 --> 00:09:07.740 the next five to ten years, they absolutely plummeted. 00:09:07.980 --> 00:09:10.259 Eventually, they fell to just two or three percent 00:09:10.259 --> 00:09:13.500 of total car sales. That is a staggering drop. 00:09:13.659 --> 00:09:16.080 It is. So what happened? It was driven by the 00:09:16.080 --> 00:09:19.580 pursuit of comfort and speed. First, optional 00:09:19.580 --> 00:09:21.240 air conditioning was gradually becoming much 00:09:21.240 --> 00:09:23.940 more popular and affordable. Which changes everything. 00:09:24.059 --> 00:09:26.840 Right. If you can push a button and have ice 00:09:26.840 --> 00:09:29.779 cold dehumidified air blow on your face, the 00:09:29.779 --> 00:09:33.039 appeal of sweating in traffic with the top down 00:09:33.039 --> 00:09:36.289 dropped significantly. Second, automakers started 00:09:36.289 --> 00:09:39.269 offering sunroofs and teatops. Those gave you 00:09:39.269 --> 00:09:41.509 a taste of the open air and the sun, but you 00:09:41.509 --> 00:09:43.909 kept the structural walls of our shoebox mostly 00:09:43.909 --> 00:09:46.769 intact. A safer compromise. Yeah, but the third 00:09:46.769 --> 00:09:49.210 reason is really fascinating. The expansion of 00:09:49.210 --> 00:09:50.990 the interstate highway system. Travel speeds 00:09:50.990 --> 00:09:53.269 were increasing dramatically. And driving 70 00:09:53.269 --> 00:09:55.389 miles per hour in a convertible with a fabric 00:09:55.389 --> 00:09:57.889 top is just an aerodynamic nightmare. Because 00:09:57.889 --> 00:10:01.450 of the noise. Noise, yes, but also physics. It's 00:10:01.450 --> 00:10:03.870 the Bernoulli principle. Oh, like airplane wings. 00:10:04.230 --> 00:10:07.690 Exactly like that. As you drive fast, the air 00:10:07.690 --> 00:10:10.169 moving over the curved top of the canvas roof 00:10:10.169 --> 00:10:12.690 travels faster than the air inside the cabin. 00:10:13.490 --> 00:10:15.889 Faster moving air creates a zone of lower pressure. 00:10:15.970 --> 00:10:18.809 Oh, wow. So at highway speeds, the air is literally 00:10:18.809 --> 00:10:21.490 sucking the canvas roof upward. That's crazy. 00:10:21.629 --> 00:10:24.730 It stretches the fabric, pulls on the frame linkages, 00:10:25.269 --> 00:10:27.509 and causes the seals around the windows to lift 00:10:27.509 --> 00:10:30.879 and leak. So you basically have a noisy ballooning 00:10:30.879 --> 00:10:33.720 roof that leaks when it rains. Add to that the 00:10:33.720 --> 00:10:36.580 emergence of much more comprehensive vehicle 00:10:36.580 --> 00:10:38.899 crash safety standards in the United States. 00:10:39.039 --> 00:10:41.120 Which was the final nail in the coffin for that 00:10:41.120 --> 00:10:43.840 era. Right. Safety watchdogs in the early 70s 00:10:43.840 --> 00:10:46.039 were looking very closely at what happens to 00:10:46.039 --> 00:10:48.179 a car without a roof in a rollover accident. 00:10:48.340 --> 00:10:50.399 The fear was that the government was going to 00:10:50.399 --> 00:10:53.860 outright ban any car without a fixed structural 00:10:53.860 --> 00:10:56.360 roof. So the U .S. automakers basically just 00:10:56.360 --> 00:10:58.799 abandoned the body style. American motors stopped 00:10:58.799 --> 00:11:03.539 in 1968, Chrysler in 1971, Ford in 1973, and 00:11:03.539 --> 00:11:06.620 most of General Motors gave up by 1975. But Cadillac. 00:11:06.759 --> 00:11:08.840 But Cadillac, they held out. They held on until 00:11:08.840 --> 00:11:13.559 1976. They produced about 14 ,000 of what they 00:11:13.559 --> 00:11:16.509 marketed heavily as the final convertibles. It 00:11:16.509 --> 00:11:18.629 was the Cadillac El Dorado. And they really leaned 00:11:18.629 --> 00:11:21.210 into the melodrama, too. The last 200 of those 00:11:21.210 --> 00:11:23.710 El Dorados featured this red, white, and blue 00:11:23.710 --> 00:11:26.590 motif, complete with a special dashboard plaque 00:11:26.590 --> 00:11:29.169 declaring it the end of an era. Very dramatic. 00:11:29.409 --> 00:11:30.889 And here's where it gets really interesting. 00:11:31.279 --> 00:11:34.440 They took the very last one off the line and 00:11:34.440 --> 00:11:36.820 offered it to the Smithsonian Institution as 00:11:36.820 --> 00:11:40.039 a historical artifact. A symbol of a bygone American 00:11:40.039 --> 00:11:43.220 era. Exactly. And the Smithsonian bluntly turned 00:11:43.220 --> 00:11:45.659 it down. So cold. Their trustees essentially 00:11:45.659 --> 00:11:47.720 said it wasn't a historic artifact right now, 00:11:47.759 --> 00:11:50.139 adding, though it might well be in three generations 00:11:50.139 --> 00:11:52.460 or at the tricentennial, which would be the year 00:11:52.460 --> 00:11:55.879 2076. Ouch. It's basically like getting dumped 00:11:55.879 --> 00:11:57.799 and then being told, maybe I'll date you in 100 00:11:57.799 --> 00:12:00.740 years. It's a brutal rejection, but it perfectly 00:12:00.649 --> 00:12:04.690 highlights the irony of the 1970s. Human innovation 00:12:04.690 --> 00:12:06.889 like air conditioning, advanced aerodynamics, 00:12:07.190 --> 00:12:10.110 faster highways solved the problem of automotive 00:12:10.110 --> 00:12:13.809 comfort. But in solving comfort, that same innovation 00:12:13.809 --> 00:12:16.830 made the visceral open experience of the convertible 00:12:16.830 --> 00:12:20.370 a massive liability. Making them on the assembly 00:12:20.370 --> 00:12:23.389 line was just too expensive and complex for the 00:12:23.389 --> 00:12:25.330 tiny fraction of buyers who still wanted them. 00:12:25.419 --> 00:12:28.240 But you can't kill a deeply ingrained cultural 00:12:28.240 --> 00:12:31.580 desire. As we move into the 1980s, the convertible 00:12:31.580 --> 00:12:34.580 mounts a massive comeback. It really did. But 00:12:34.580 --> 00:12:36.899 because safety standards had nearly regulated 00:12:36.899 --> 00:12:40.220 it out of existence, it required incredibly specialized 00:12:40.220 --> 00:12:42.320 high tech engineering to bring it back to life. 00:12:42.500 --> 00:12:44.440 And the revival actually started underground, 00:12:44.519 --> 00:12:46.899 in a sense, with specialized coach builders. 00:12:47.039 --> 00:12:49.340 Like third party shops. Yeah. Companies outside 00:12:49.340 --> 00:12:51.759 the main automakers were contracted to make dealer 00:12:51.759 --> 00:12:53.840 available conversions. For example, American 00:12:53.840 --> 00:12:57.759 Sunroof Company or ASC. OK. In 1982, they figured 00:12:57.759 --> 00:13:00.720 out how to heavily modify and convert a Buick 00:13:00.720 --> 00:13:03.240 Riviera into a full convertible that actually 00:13:03.240 --> 00:13:05.779 meant safety. standards. And they did it so well 00:13:05.779 --> 00:13:08.039 that General Motors actually marketed it as part 00:13:08.039 --> 00:13:11.340 of their official 1982 Buick lineup. Chrysler 00:13:11.340 --> 00:13:13.899 jumped back in that same year with K -Car convertibles. 00:13:14.120 --> 00:13:15.980 Ford brought back the convertible Mustang in 00:13:15.980 --> 00:13:18.820 1983. But the real watershed moment, the car 00:13:18.820 --> 00:13:21.100 that proved the convertible wasn't just a nostalgic 00:13:21.100 --> 00:13:25.600 novelty, came a bit later in 1989. Ah, yes. The 00:13:25.600 --> 00:13:28.340 release of the first -generation Mazda MX -5, 00:13:28.440 --> 00:13:31.509 known in North America as the Miata. The Viada 00:13:31.509 --> 00:13:33.710 became the best -selling convertible ever, with 00:13:33.710 --> 00:13:36.990 over one million cars sold. It proved there was 00:13:36.990 --> 00:13:40.049 a massive, enduring market for a dedicated, open 00:13:40.049 --> 00:13:42.889 -air roadster. Absolutely. But to sell convertibles 00:13:42.889 --> 00:13:45.529 to a modern audience, automakers really had to 00:13:45.529 --> 00:13:48.269 solve those 1970s rollover and safety issues 00:13:48.269 --> 00:13:50.850 we talked about. And the engineering workarounds 00:13:50.850 --> 00:13:53.590 are genuinely staggering. They're essentially 00:13:53.590 --> 00:13:55.649 rolling science experiments. Let's talk about 00:13:55.649 --> 00:13:58.009 rollovers. Modern convertibles feature rollover 00:13:58.009 --> 00:14:00.899 protection structures, or ROPS. Because you no 00:14:00.899 --> 00:14:02.860 longer have a steel roof to keep the car from 00:14:02.860 --> 00:14:04.980 crushing the occupants if it flips. Right, so 00:14:04.980 --> 00:14:07.620 they use pyrotechnically charged roll hoops hidden 00:14:07.620 --> 00:14:09.960 completely out of sight behind the rear seats. 00:14:10.279 --> 00:14:12.519 Wait, pyrotechnic meaning explosives. Exactly. 00:14:12.879 --> 00:14:15.539 If the car's gyroscopes and accelerometers detect 00:14:15.539 --> 00:14:17.679 that a rollover is imminent, and we are talking 00:14:17.679 --> 00:14:20.419 about calculations made in milliseconds, small 00:14:20.419 --> 00:14:23.179 explosive charges detonate. Yeah, they deploy 00:14:23.179 --> 00:14:25.679 these high -strength steel hoops upward to protect 00:14:25.679 --> 00:14:27.659 the occupants' heads before the car even hits 00:14:27.659 --> 00:14:30.360 the ground. That is incredible engineering. They 00:14:30.360 --> 00:14:34.080 also heavily utilize boron steel for the A -pillars. 00:14:34.299 --> 00:14:36.460 Now I initially assumed they just made the A 00:14:36.460 --> 00:14:39.259 -pillars thicker, but you can't do that without 00:14:39.259 --> 00:14:41.340 creating a massive blind spot for the driver, 00:14:41.399 --> 00:14:43.519 right? Precisely. If you just use thicker standard 00:14:43.519 --> 00:14:46.120 steel, the pillar becomes so wide you can't see 00:14:46.120 --> 00:14:49.980 traffic at an intersection. Boron steel solves 00:14:49.980 --> 00:14:53.299 this. How does it work? By alloying steel with 00:14:53.299 --> 00:14:56.639 a tiny amount of boron. it drastically increases 00:14:56.639 --> 00:14:58.600 the metal's hardenability during heat treatment. 00:14:59.480 --> 00:15:01.840 When it's heated and then rapidly cooled, a process 00:15:01.840 --> 00:15:04.679 called quenching, the molecular structure changes 00:15:04.679 --> 00:15:07.320 into something called martensite. Which is super 00:15:07.320 --> 00:15:09.779 strong. Exceptionally strong. So you get an A 00:15:09.779 --> 00:15:11.759 pillar that is thin enough to see around, but 00:15:11.759 --> 00:15:13.559 strong enough to support the entire weight of 00:15:13.559 --> 00:15:16.299 an inverted car. Exactly. And then there are 00:15:16.299 --> 00:15:19.340 the side impact airbags. In a normal car, the 00:15:19.340 --> 00:15:21.840 side curtain airbag drops down from the roofline. 00:15:22.480 --> 00:15:24.860 But a convertible has no roofline to store an 00:15:24.860 --> 00:15:27.419 airbag in. So where do they put them? They engineered 00:15:27.419 --> 00:15:31.100 door -mounted side impact airbags that cleverly 00:15:31.100 --> 00:15:34.039 inflate upward instead of downward. Upward. Yeah. 00:15:34.259 --> 00:15:36.700 They shoot up out of the door sill to provide 00:15:36.700 --> 00:15:38.960 head protection even if the window is open and 00:15:38.960 --> 00:15:40.980 the roof is completely gone. It's brilliant. 00:15:41.179 --> 00:15:43.980 Yeah. And beyond safety, they had to solve the 00:15:43.980 --> 00:15:46.159 comfort issues that killed the convertible in 00:15:46.159 --> 00:15:49.179 the 70s, like the noise and the wind buffeting 00:15:49.179 --> 00:15:51.720 at highway speeds. The light. Have you ever wondered 00:15:51.720 --> 00:15:54.039 why, when you drive a convertible fast, your 00:15:54.039 --> 00:15:57.159 hair blows forward, into your face? Yes, it makes 00:15:57.159 --> 00:15:59.000 no sense. The wind is hitting the front of the 00:15:59.000 --> 00:16:00.679 car. Why is it attacking the back of my head? 00:16:00.779 --> 00:16:03.919 It's fluid dynamics. As the air rushes over the 00:16:03.919 --> 00:16:06.480 windshield, it separates and flows over the cabin, 00:16:06.840 --> 00:16:08.700 creating a low -pressure pocket right where you're 00:16:08.700 --> 00:16:11.120 sitting. Oh, I see. So high pressure air from 00:16:11.120 --> 00:16:13.899 behind the car naturally rushes forward to fill 00:16:13.899 --> 00:16:16.659 that low pressure void. It creates a swirling 00:16:16.659 --> 00:16:19.759 vortex right behind your head. Ah, so that's 00:16:19.759 --> 00:16:22.259 what wind blockers are for. Exactly. Those mesh 00:16:22.259 --> 00:16:24.519 screens you see behind the front seats disrupt 00:16:24.519 --> 00:16:27.679 that vortex. They allow just enough air through 00:16:27.679 --> 00:16:30.480 to equalize the pressure without creating a turbulent 00:16:30.480 --> 00:16:33.090 draft. Do they actually work that well? Oh, yeah. 00:16:33.429 --> 00:16:36.570 On the 2008 Chrysler Sebring, the chief engineer 00:16:36.570 --> 00:16:38.950 noted that their wind blocker reduced wind noise 00:16:38.950 --> 00:16:42.350 in the cabin by approximately 11 to 12 decibels. 00:16:42.490 --> 00:16:44.629 Wow, that is a massive reduction in acoustic 00:16:44.629 --> 00:16:46.929 energy. They even tackled the temperature issue 00:16:46.929 --> 00:16:49.610 with things like the airscarf. What's that? It's 00:16:49.610 --> 00:16:51.669 a heating duct built right into the headrest 00:16:51.669 --> 00:16:54.029 that blows warm air directly onto your neck. 00:16:54.210 --> 00:16:57.210 Cars like the Mercedes SLK and the Audi A5 use 00:16:57.210 --> 00:17:00.080 this. Oh, that sounds amazing. So what does this 00:17:00.080 --> 00:17:02.700 all mean? The modern convertible is basically 00:17:02.700 --> 00:17:05.779 a disguised, highly technical open -air fortress. 00:17:06.339 --> 00:17:08.380 Engineering an airbag to shoot upward because 00:17:08.380 --> 00:17:10.880 there's no roof to bounce off of is an absolutely 00:17:10.880 --> 00:17:13.660 brilliant workaround. It is, but it raises an 00:17:13.660 --> 00:17:16.000 important question about our willingness to over 00:17:16.000 --> 00:17:18.900 -engineer solutions. Think about the complex 00:17:18.900 --> 00:17:22.019 folding mechanisms, the stack, and the tonneau 00:17:22.019 --> 00:17:24.140 covers required to hide the top. It's so much 00:17:24.140 --> 00:17:26.950 machinery. Exactly. It's incredibly complex, 00:17:27.150 --> 00:17:29.750 all just to safely simulate the simple feeling 00:17:29.750 --> 00:17:32.809 of the wind. And this relentless drive to balance 00:17:32.809 --> 00:17:35.410 structural integrity, safety, and open air freedom 00:17:35.410 --> 00:17:39.250 has led automakers to invent some truly bizarre 00:17:39.250 --> 00:17:41.630 variations of the convertible roof. Let's look 00:17:41.630 --> 00:17:43.529 at a few of those from the source. We can start 00:17:43.529 --> 00:17:45.980 with the traditional soft top. After World War 00:17:45.980 --> 00:17:48.099 II, automakers actually struggled to secure enough 00:17:48.099 --> 00:17:51.480 tightly woven waterproof cotton canvas due to 00:17:51.480 --> 00:17:53.440 raw material shortages. So the materials had 00:17:53.440 --> 00:17:57.119 to evolve. Right. Today, they often use a complex 00:17:57.119 --> 00:18:00.359 polyvinyl chloride or PVC material. It's usually 00:18:00.359 --> 00:18:03.980 two layers, a specific PVC top layer over a cotton 00:18:03.980 --> 00:18:06.500 fabric lower layer. And it's packed with sound 00:18:06.500 --> 00:18:09.099 deadening linings. But some people want the quiet 00:18:09.099 --> 00:18:11.140 and security of a solid roof without giving up 00:18:11.140 --> 00:18:12.779 the convertible option. Yeah. So you have hard 00:18:12.779 --> 00:18:15.000 tops. Yeah. detachable hardtops go way back. 00:18:15.440 --> 00:18:17.779 In the 1930s, you had the Carson top, which is 00:18:17.779 --> 00:18:20.059 a metal -framed removable hardtop for Fords. 00:18:20.700 --> 00:18:22.920 Because it didn't need the bulky folding mechanisms 00:18:22.920 --> 00:18:25.740 of a soft top, it gave the car a much lower, 00:18:25.819 --> 00:18:28.660 more aggressive profile. And in the 1950s and 00:18:28.660 --> 00:18:31.960 60s, cars like the Ford Thunderbird and the Chevrolet 00:18:31.960 --> 00:18:35.859 Corvette offered detachable hardtops. Great weatherproofing, 00:18:35.900 --> 00:18:38.779 but the glaring problem is, what do you do with 00:18:38.779 --> 00:18:40.619 the roof when you take it off? You need a whole 00:18:40.619 --> 00:18:43.259 garage with a hoist just to store it. Exactly. 00:18:43.619 --> 00:18:47.359 Which led to the retractable hardtop, where complex 00:18:47.359 --> 00:18:50.119 hydraulics fold the metal roof up into the trunk. 00:18:50.299 --> 00:18:52.140 But that adds a massive amount of weight, shifts 00:18:52.140 --> 00:18:54.240 the car's center of gravity, and essentially 00:18:54.240 --> 00:18:57.019 eliminates your luggage space. So what if you 00:18:57.019 --> 00:18:59.720 want to keep your structural rigidity, keep your 00:18:59.720 --> 00:19:02.319 trunk, but still have an open roof? That leads 00:19:02.319 --> 00:19:05.500 to some fascinating structural compromises. First, 00:19:05.880 --> 00:19:08.420 you have the cabrio coach, also known as the 00:19:08.420 --> 00:19:10.279 semi -convertible. Okay, let's bring back our 00:19:10.279 --> 00:19:12.619 shoebox. A traditional convertible removes the 00:19:12.619 --> 00:19:14.619 entire lid and the upper halves of the sides. 00:19:14.720 --> 00:19:17.440 Right, but a cabrio coach retains all the bodywork 00:19:17.440 --> 00:19:20.359 up to the top of the door frames. The A, B, and 00:19:20.359 --> 00:19:23.380 C pillars all stay intact. Oh, I see. It just 00:19:23.380 --> 00:19:25.920 replaces the roof skin itself with a retractable 00:19:25.920 --> 00:19:30.019 fabric panel. The Citroen C3 Plurial uses this. 00:19:30.400 --> 00:19:32.920 By keeping the walls of the shoebox, the car's 00:19:32.920 --> 00:19:35.259 rigidity is much higher and the weight is lower 00:19:35.259 --> 00:19:37.160 compared to a full convertible. You also have 00:19:37.160 --> 00:19:39.400 the fixed profile convertible. This is where 00:19:39.400 --> 00:19:42.039 the car keeps its rigid doors, side pillars, 00:19:42.140 --> 00:19:45.140 and the side metal rails of the roof while just 00:19:45.140 --> 00:19:47.839 a center fabric portion slides back and accordions 00:19:47.839 --> 00:19:51.960 at the rear. Like the Fiat 500. Yes. The classic 00:19:51.960 --> 00:19:57.039 1957 Fiat 500 and its 2007 successor, use this 00:19:57.039 --> 00:19:59.859 design. It's a clever way to solve the shoebox 00:19:59.859 --> 00:20:02.059 problem without totally sacrificing the open 00:20:02.059 --> 00:20:03.940 -air feel. Then you have the highly specialized 00:20:03.940 --> 00:20:05.779 variations, the landelay, which we mentioned 00:20:05.779 --> 00:20:08.259 earlier with horse carriages. In a modern landelay, 00:20:08.319 --> 00:20:11.059 the driver is completely enclosed. often separated 00:20:11.059 --> 00:20:13.259 by a partition. While the rear passengers are 00:20:13.259 --> 00:20:15.200 covered by a convertible top that folds down. 00:20:15.359 --> 00:20:17.960 Exactly. It's the ultimate VIP parade car. It 00:20:17.960 --> 00:20:20.599 was. In the second half of the 20th century, 00:20:20.880 --> 00:20:22.980 Landalez were frequently used by heads of state 00:20:22.980 --> 00:20:25.819 for formal processions, but they are practically 00:20:25.819 --> 00:20:28.779 extinct today due to modern security protocols 00:20:28.779 --> 00:20:31.599 and terrorism fears. The lack of occupant security 00:20:31.599 --> 00:20:34.299 just made them entirely too risky. Finally, looking 00:20:34.299 --> 00:20:36.559 at the source, we have to talk about four -door 00:20:36.559 --> 00:20:38.880 convertibles. Most convertibles only have two 00:20:38.880 --> 00:20:42.940 doors. Why? Because adding two more huge, gaping 00:20:42.940 --> 00:20:45.460 holes in the side of your lidless shoebox is 00:20:45.460 --> 00:20:48.700 an absolute nightmare for rigidity. Historically, 00:20:48.980 --> 00:20:51.779 they existed, the 1961 Lincoln Continental being 00:20:51.779 --> 00:20:55.000 famous for its suicide doors, but they are incredibly 00:20:55.000 --> 00:20:58.460 rare today. However, Peugeot presented a concept 00:20:58.460 --> 00:21:02.180 car in 2006 called the 407 Macarena. Produced 00:21:02.180 --> 00:21:04.559 by the French coach builder, Juli, right? It 00:21:04.559 --> 00:21:07.359 was a four -door retractable hardtop that can 00:21:07.359 --> 00:21:09.500 fold away in 60 seconds. But the engineering 00:21:09.500 --> 00:21:11.440 workaround is what's crazy, because they needed 00:21:11.440 --> 00:21:14.279 a massive steel -reinforcing cross -member beam 00:21:14.279 --> 00:21:16.299 right behind the front seats just to keep the 00:21:16.299 --> 00:21:18.400 car from folding in half. Essentially taping 00:21:18.400 --> 00:21:20.480 a thick wooden dowel across the middle of our 00:21:20.480 --> 00:21:23.819 shoebox. Yes. And they decided to embed LCD screens 00:21:23.819 --> 00:21:26.329 for the rear passengers right into that beam. 00:21:26.650 --> 00:21:29.170 Wait, packing luxury tech into the one solid 00:21:29.170 --> 00:21:31.630 piece of structural lifeline you have left? That 00:21:31.630 --> 00:21:34.390 is a wild aesthetic choice. It perfectly illustrates 00:21:34.390 --> 00:21:37.109 the physical trade -offs at play in every single 00:21:37.109 --> 00:21:39.349 variation we've discussed today. For sure. If 00:21:39.349 --> 00:21:42.250 you want maximum security and a hard roof, you 00:21:42.250 --> 00:21:45.210 lose your trunk space. If you want a parade -friendly 00:21:45.210 --> 00:21:48.410 land delay, you lose VIP security. If you want 00:21:48.410 --> 00:21:51.529 four doors, you need a massive structural beam 00:21:51.529 --> 00:21:54.690 behind your head. Every single convertible design 00:21:54.690 --> 00:21:57.569 is a strict negotiation with physics. It really 00:21:57.569 --> 00:21:59.869 is. We've covered an incredible amount of ground 00:21:59.869 --> 00:22:02.250 today. For you listening, we've journeyed all 00:22:02.250 --> 00:22:05.430 the way from light horse -drawn carriages to 00:22:05.430 --> 00:22:08.349 early cars using engine vacuum cylinders just 00:22:08.349 --> 00:22:11.009 to hoist a canvas roof. We saw how World War 00:22:11.009 --> 00:22:13.630 II and European roadsters completely shifted 00:22:13.630 --> 00:22:15.950 American car culture, leading to the massive 00:22:15.950 --> 00:22:18.650 unibody cruisers of the 50s. Followed by a near 00:22:18.650 --> 00:22:21.329 extinction of the style in the 70s, where aerodynamic 00:22:21.329 --> 00:22:23.869 physics and safety fears led even the Smithsonian 00:22:23.869 --> 00:22:26.130 to think the convertible belonged only in the 00:22:26.130 --> 00:22:28.490 history books. Only to see it saved by incredible 00:22:28.490 --> 00:22:30.970 modern engineering marvels like Boron steel, 00:22:31.430 --> 00:22:33.769 pyrotechnic roll hoops, and aerodynamic mesh 00:22:33.769 --> 00:22:36.269 wind blockers. The next time you see a convertible 00:22:36.269 --> 00:22:38.190 driving down the road, You aren't just going 00:22:38.190 --> 00:22:41.250 to see a fun, breezy car. You are looking at 00:22:41.250 --> 00:22:45.450 a rolling paradox of engineering, fluid dynamics, 00:22:46.029 --> 00:22:49.329 and history. It's a massive mechanical testament 00:22:49.329 --> 00:22:52.710 to how badly we want to feel connected to the 00:22:52.710 --> 00:22:54.930 environment around us. And that actually brings 00:22:54.930 --> 00:22:56.809 up a final thought for you to mull over as we 00:22:56.809 --> 00:22:59.680 wrap up this deep dive. Beyond the engineering 00:22:59.680 --> 00:23:03.240 and the history, consider the psychological shift 00:23:03.240 --> 00:23:05.160 that happens when you take the roof off a car. 00:23:05.319 --> 00:23:08.440 Oh, it's profound. When you drive a sealed hardtop 00:23:08.440 --> 00:23:11.079 car, you are essentially an observer. You're 00:23:11.079 --> 00:23:13.579 sitting in a private climate -controlled isolation 00:23:13.579 --> 00:23:16.640 chamber watching the world pass by through glass 00:23:16.640 --> 00:23:19.039 screens. You're entirely separated from the environment. 00:23:19.289 --> 00:23:21.369 But the second you fold that roof down, that 00:23:21.369 --> 00:23:23.589 dynamic completely flips. You are no longer just 00:23:23.589 --> 00:23:25.589 an observer. You suddenly become a participant 00:23:25.589 --> 00:23:27.690 in the world. Yeah, that's so true. You are exposed 00:23:27.690 --> 00:23:30.049 to the smells, the temperature changes, the noise. 00:23:30.609 --> 00:23:33.049 But more profoundly, you become actively perceived 00:23:33.049 --> 00:23:35.950 by everyone else. The car transitions from being 00:23:35.950 --> 00:23:39.150 a private room into a public stage, and the driver 00:23:39.150 --> 00:23:42.269 becomes part of the scenery. It changes not just... 00:23:42.170 --> 00:23:44.390 how you see the road, but how the world sees 00:23:44.390 --> 00:23:47.450 you. It's an act of vulnerability. It is. We 00:23:47.450 --> 00:23:49.589 take the lid off the shoebox, not just to feel 00:23:49.589 --> 00:23:51.970 the wind, but to step out into the world. Thanks 00:23:51.970 --> 00:23:53.430 for joining us on this deep dive.