1949 Nash Airflyte: Why The “Bathtub Nash” Was The Most Advanced And Aerodynamic U.S. Car Of Its Time

Never very fast, but lightweight and impressively sleek, the 1949 Nash “Airflyte” 600 and Ambassador were some of the most advanced production cars of their day, with sturdy unit-body construction and an aerodynamic drag coefficient that would still have been respectable three decades later. Let’s take a look at the sophisticated engineering of the “Bathtub Nash” and see how its wind tunnel performance compared to a range of other 1948–1949 American cars.

If even some of the innovative advanced engineering taking place at Nash Motors in the 1940s had been directed towards the engine compartment, Nash would probably be at least as warmly remembered today as Oldsmobile, and there would be click-bait articles every other month lauding the 1949 Nash Ambassador and 600 as “early muscle cars.”

Alas, the 1949 Nash Airflyte cars were developed just before the horsepower race really began, in a period when postwar American buyers and manufacturers were less worried about power than about the rising cost of gasoline. Gas was fairly expensive in the late ’40s, and the average price per gallon climbed over 28 percent between 1945 and 1949.

The smaller Nash 600 Airflyte (renamed Nash Statesman for 1950) used the same 172.6-cid L-head six later used in the early Nash Rambler. With 82 gross hp to move over 3,000 lb of curb weight, the British magazine The Motor found that the 600 needed over 25 seconds to hit 60 mph, although the optional overdrive (with automatic kickdown to direct third) allowed the Nash to cruise comfortably at its 80 mph top speed while returning a very decent 20 miles per U.S. gallon.

The long-nose Nash Ambassador had a bigger 234.8-cid six with overhead valves, but its greater torque and 30 extra hp were offset by an additional 415 lb. Tom McCahill’s Mechanix Illustrated road test found the 1949 Ambassador was 2.7 seconds quicker to 60 mph than the 600, but it was still no match for the cheaper Olds Rocket 88. The Ambassador six wasn’t immune to a little hopping up (as Donald Healey subsequently demonstrated with the Nash Healey sports car), but the big Nash really wasn’t a car people bought for speed.

That was true of a lot of mid-price cars of the late ’40s — the Ambassador was in the same price class as the Buick Super or Chrysler Windsor, which weren’t significantly more powerful — but those were conservatively engineered, orthodox-looking models, so they didn’t prompt the same kind of jokes and jeering as the “Bathtub” Nash Airflyte cars.

Fastbacks were still common among American cars of the late ’40s, but the Nash Airflyte models WERE a bit funny-looking, with their enclosed front wheels and pigeon-toed stance.

The optional fold-down seat and twin bed mattress drew jokes of their own, no matter how innocent Nash brochures tried to make them seem.

Jokes and horsepower notwithstanding, the “Bathtub” Nash was one of the most sophisticated American cars on the road in 1949. For starters, it had a one-piece curved windshield when most rivals still used split glass.

All-welded frame-integral unitized construction, which Nash had first introduced on the 600 in 1941, made the Airflyte cars stiff, strong, and surprisingly light. A 1949 Ambassador was about 500 lb lighter than the body-on-frame 1949 Buick Super, whose exterior dimensions were similar.

Like Buick, Nash used coil springs all around with torque tube drive, giving it a very cushy ride. Handling was not a strong point, with rather extreme body lean in even moderately fast turns, but the Airflyte cars were quite rugged. Five Ambassadors, one driven by NASCAR founder Bill France, would compete in the grueling Carrera Panamericana Mexican road race in October 1950, with several more entering the 1951 race.

Befitting its fairly high prices, even the cheaper Nash 600 Super was plush inside, and there was lots of space.

The novel Uniscope instrument pod contained water temperature, oil pressure, and fuel gauges in addition to the speedometer. It made the instruments easy to see, although fixing wiring problems with the gauges was a bear.

The two-door Brougham, offered in all series for 1949, included unusual divided “theater seating” in back.

Another key Nash feature was an improved version of the Weather Eye “conditioned air” heating and ventilation system, which offered thermostatically controlled fresh air heating with a dust and pollen filter (a feature that didn’t really show up on modern cars until the ’90s). Weather Eye was improved for 1949 by adding a pressurizing fan to boost airflow at low speeds; earlier versions had relied on the ram effect of the cowl vent. This was the best heater in the business, and probably safer than the cheap recirculating heaters offered on many cars of the time.

In the Wind Tunnel

The big emphasis of the 1949 Nash, on which the company had spent a reported $15 million (the equivalent of about $732 million in 2025, based on GDP per capita), was aerodynamics. This of course wasn’t a new idea for cars — engineers like Edmund Rumpler, Paul Jaray, and others had done a lot of important work on automobile aerodynamics even in the 1920s — but it had yet to really catch on in the United States.

During the war, Nash chief engineer Nils Wahlberg and body designer Don Mortrude were working on military aircraft engines, but they started a side project to build an full-size plaster model of an aerodynamic postwar car, which they tested in a wind tunnel in Milwaukee. In August 1943, freelance designer Holden (Bob) Koto also showed Wahlberg a scale model of his own aerodynamic design, which Koto later claimed looked a great deal like the 1949 Nash. (Wahlberg, who saw Koto’s model only for an hour or two, said he didn’t remember it.)

Wahlberg kept working on the “Milwaukee Job,” refining its performance in the wind tunnel before the model was eventually transferred to Kenosha. Until the late ’70s, the American auto industry was often disdainful, if not actually contemptuous, of aerodynamics — cultivating a streamlined look was one thing, but aerodynamically ideal teardrop shapes weren’t very practical for cars, and the lackluster commercial response to the Chrysler Airflow models of the mid-1930s hadn’t really encouraged further efforts along those lines. However, Nash-Kelvinator president George W. Mason was enthusiastic. Mason had an engineering background, but he was also a salesman who loved a good gimmick, and he was very keen on any readily identifiable, boast-worthy feature Nash could offer that the competition didn’t.

So, the 1949 Nash body was shaped and tailored for better aerodynamics, with a sloping roof and the enclosed front wheels that would become a Nash signature until after Mason’s death in 1954. The front track of the Airflyte was 5 inches narrower than the rear so that steering lock wouldn’t be too limited, although the turning radius was still a little cumbersome. Unladen height was reduced by over 5 inches from 1948, and Wahlberg paid careful attention to reducing panel gaps so that air would flow more cleanly around the car.

In the spring of 1949, Nash took a small fleet of cars to the Kansas for aerodynamic testing in the wind tunnel of the University of Wichita School of Engineering, which at the time was the largest wind tunnel available in the U.S. for commercial use. Nash engineers worked with School of Engineering director Kenneth Razak to measure the aerodynamic drag and calculate the drag coefficients of the 1949 Nash Ambassador, 1946 and 1947 Nash sedans, and 10 models from rival automakers. (Unfortunately, they did NOT bring a 1949 Nash 600, which is too bad — it would have been interesting to see how its shorter nose affected its aerodynamic performance compared to the Ambassador, which used the same body from the cowl back, but had a longer front end to accommodate its bigger engine.)

When Nash consultant Larry Nagler presented the test data to the Society of Automotive Engineers (SAE) in January 1950, the test results for the competitors’ cars were identified only by letter codes. (Nagler did specify which cars they tested, just not which wind tunnel results went with which car, in the spirit of discretion.) However, in the early ’70s, writer Michael Lamm talked to Nagler and was able to identify the car that each letter represented, which has enabled me to compile some key data into the following table:

Identifier	Model	Body Style	Frontal Area, sq. ft.	Cd	Air Drag at 60 mph, lb	Air Drag at 60 mph, hp	Air Drag at 80 mph, lb	Air Drag at 80 mph, hp
Ambassador	1949 Nash Ambassador	four-door sedan	30.9	0.43	113	18.1	205	43.6
A	1949 Lincoln Cosmpolitan	four-door sedan	33.4	0.47	133	21.3	238	50.8
B	1948 Studebaker Champion	two-door sedan	27.5	0.50	118	18.9	211	45.0
C	1949 Hudson Commodore 6	four-door sedan	29.9	0.51	129	20.6	232	49.5
D	1949 Oldsmobile 88	four-door fastback	30.9	0.52	136	21.7	240	51.2
E	1949 Ford 6	four-door sedan	30.4	0.52	136	21.7	240	51.2
K	1949 Kaiser	four-door sedan	30.4	0.52	135	21.6	240	51.2
F	1949 Pontiac Chieftain 6	four-door notchback	31.8	0.54	146	37.2	260	55.5
G	1949 Chrysler Windsor	four-door sedan	31.0	0.57	151	38.5	269	57.3
H	1949 Buick Roadmaster	four-door notchback	33.1	0.58	164	41.7	292	62.3
I	1949 Packard Custom 8	four-door sedan	33.6	0.60	171	43.0	304	64.8

As you can see, the 1949 Ambassador had the lowest drag of the test cars, a little better than even the smaller but somewhat draggier 1948 Studebaker. (Although it wasn’t discussed in the SAE paper, Lamm said Nash also tested a 1950 Studebaker, which had very slightly less air drag than the ’48 car, albeit still a bit more than the Nash.)

I should point out that the drag coefficients they calculated aren’t necessarily comparable to the results that would be obtained in a bigger modern wind tunnel. The Wichita tunnel was fairly small, which put the sides of each test vehicle fairly close to the tunnel walls, resulting in greater total drag. Razan came up with a correction factor to account for that; the drag measurements in the table are corrected figures, which were used to calculate the drag coefficients. Nagler and Razan later decided their correction factor may have been a little too high, which would have made the calculated drag coefficients too high as well, perhaps by as much as 12 percent. However, Nagler stressed that the actual observed drag figures were quite accurate, and the correction factor was the same for all the cars tested, so the RELATIVE values were still valid, even if the corrected drag figures were higher than they might have been in freer air.

In any event, the 0.43 Cd they calculated for the 1949 Ambassador would still have been very good even 15 years later, and decent enough by the standards of the late ’70s or early ’80s. The Ambassador had a lot of frontal area, 30.9 square feet, but it nonetheless had about 20 percent less aerodynamic drag than the average of its competitors — the time Wahlberg had spent in the wind tunnel in Milwaukee had not been in vain.

I thought about doing a car-by-car breakdown of the test results, as I previously did with the 1960 model wind tunnel data Ford collected about a decade later, but I don’t know if even many die-hard CC fans are that keen to analyze the aerodynamics of the 1949 Kaiser. However, I will note a couple of interesting points:

GM’s 1949 A-Body Fastback Really Was More Aerodynamic Than the Notchback.

The four-door Oldsmobile Futuramic 88 Town Sedan tested had almost 8 percent less drag than the notchback Pontiac Chieftain 6. Nagler and Razan felt these results would apply equally well to other GM cars using the same A-body shell, including the 1949 Chevrolet.

Both versions of the GM A-body were also substantially less draggy than the bigger GM B-body notchback cars, represented by the Buick Roadmaster four-door sedan. (Nash unfortunately didn’t test a big Buick or Oldsmobile fastback.)

Fastbacks Didn’t Necessarily Have Less Drag Than Notchbacks.

The notchback 1949 Ford four-door sedan Nash tested proved to be just as slippery as the fastback Oldsmobile in the wind tunnel.

Both notchback Studebaker sedans had about 4 percent less drag than either the Ford or the Oldsmobile.

Looking Streamlined Was Definitely Not the Same as Being Aerodynamic.

Although it wasn’t included in the data tables, the wind tunnel performance of the outgoing 1946–1948 Nash “Slipstream” fastback sedan turned out to be pretty terrible. Based on the limited data presented, which indicated a frontal area of 32.0 square feet and corrected drag of 162 lb at 60 mph, I calculated a dismal Cd of 0.60.

The 22nd Series Packard Custom Eight sedan Nash tested, which looked almost as bathtub-like as the Nash Airflyte, actually had the worst aerodynamics of the bunch, with the biggest frontal area AND the worst drag coefficient.

The Packard had much more drag than the 1949 Lincoln Cosmopolitan, which had almost as much frontal area, but turned out to have a substantially better drag coefficient.

Enclosed Front Wheels Did Help Aerodynamics … a Little.

There was no practical way to assess the contribution of the Ambassador’s enclosed front wheels to its wind tunnel performance, but Nash tried fashioning Masonite front wheel skirts for some of the other cars, and found that they reduced air drag by between 1 and 2 percent.

Those External Sun Visors Hurt Aerodynamics a Lot.

Modern collectors of ’40s cars seem to love accessory sun visors, the same way collectors of ’50s cars love Continental kits. Several of the cars Nash brought to Wichita in 1949 had external sun visors, which were removed for the tests summarized in the table I presented above.

However, Nash did try testing several of the cars both with and without their external sun visors. Unsurprisingly, they found that installing an external visor increased drag, by about 9 percent. On the Ambassador, Nash estimated that that would cost about 1 mpg at 60 mph. These visors made more sense on slow country roads than on postwar freeways.

A Streamlined Prophet Without Honor

Seen today, the Bathtub Nash looks just about as dated as other cars of its era, but with their aerodynamic design, unit construction, and efficient overdrive (Hydra-Matic became optional in 1950), the Airflyte cars were way ahead of their time. Nash said as much in its advertising, insisting that other automakers would eventually copy the Airflyte cars’ “ahead-of-the-crowd features.” Ultimately, that was true, although it took much longer than Nash assumed.

Why? In the late ’40s and early ’50s, aerodynamic performance was still an academic point for most American motorists. As Nash conceded, air drag didn’t begin to exceed rolling resistance (drag from tires and drivetrain friction0 until some point between 40 and 50 mph, and most Americans didn’t spend a lot of time at speeds much higher than that. In 1949, 34 U.S. states already had statewide speed limits of 65 mph or less, and limits at night or on rural roads were usually a lot lower. The Ambassador and 600/Statesman were aerodynamic enough to save about 1 mpg in 60 mph cruising, which owners appreciated, but the price of gasoline plateaued in 1949–1950, and inflation-adjusted gas prices steadily diminished from 1954 to 1973, making fuel economy a lower priority for many U.S. new car buyers than it had been just after the war.

Except for Hudson, the rest of the U.S. auto industry wasn’t very interested in unit construction either — the higher tooling costs cut into profits, and unit bodies didn’t lend themselves to the frequent styling changes to which the big automakers had become wedded. AMC (formed from the 1954 merger of Nash and Hudson) continued to use unit construction, and Ford adopted it for the 1958 Thunderbird and Lincoln, but of the Big Three, only Chrysler embraced unit construction on a mostly line-wide basis, adopting it for all models except the low-production Imperial in 1960. GM continued to insist that unitized construction was unsuitable for larger cars, and Ford eventually followed GM’s lead back to perimeter frames for many of its bigger models.

The Bathtub Nash actually sold quite well when these cars were new: 1949–1951 production totaled 415,528 units, very good for an independent automaker. However, they were not popular as used cars — the oddball styling, fears of expensive body repair, and problems with rust in the sills all contributed to poor resale values. Consequently, their survival rates were not great. Based on R.L. Polk registration data, fewer than one-third of 1949 and 1950 Airflyte cars were still on the road by mid-1959.

It hardly seems fair, since the Nash Airflyte cars were very good at most of the things American drivers valued: They were roomy, quiet, soft-riding, comfortable cruisers, available with plush trim and useful features. The only major areas where these cars fell a bit short were flashy looks and flashy acceleration. Unfortunately for Nash, by the mid-’50s, the importance of those things had begun to eclipse almost everything else.

Related Reading

Curbside Classic: 1950 Nash Ambassador – Long Nosed Bathtub (by Paul N)

Curbside Classic: 1950 Nash Statesman Airflyte: Did Somebody Say Bathtub? (by Tom Klockau)

Vintage Snapshots: A Gallery Of Nash And Rambler Owners – ‘Bathtubs’ And Beyond (by Rich Baron)

Automotive History Outtake: The 1935 Stout Scarab Reappears Fifteen Years Later As The 1949 Nash Airflyte (by Paul N)

An Illustrated History Of Automotive Aerodynamics – Part 1 (1899 – 1939) (by Paul N)

An Illustrated History Of Automotive Aerodynamics: Part 2 (1940 – 1959) (by Paul N)

An Illustrated History Of Automotive Aerodynamics: Part 3 (1960 – 2012) (by Paul N)

How Aerodynamic Were Old Cars? Here’s Actual Wind Tunnel Data On Some 1960 Models. (by me)