Simanaitis Says

On cars, old, new and future; science & technology; vintage airplanes, computer flight simulation of them; Sherlockiana; our English language; travel; and other stuff

SAAB 21—WHERE’S MY PROP?

THE NAME Saab stands for Svenska Aeroplan Aktiebolaget, Swedish Aeroplane Ltd. In fact, this company founded in 1937 didn’t built cars until a decade later.

Saab’s original badge as an aeroplane builder in 1937. Later, see below, it was to update this logo for its automotive side.

And two of the most curious Saabs, the 21A and 21R aircraft, predated the cars.

Initiated in 1943 during Sweden’s complex neutrality in World War II, the 21A single-seat fighter was an unorthodox design with a pusher prop necessitating a twin-boom tail. Think a Lockheed P-38 Lightning, but with single Daimler Benz straight-12 facing aft.

This layout had an advantage of concentrating its firepower in the nose, with quad machine guns and a 20-mm cannon. Also the pilot gained an unobstructed view ahead.

All Saab 21 variants, including this pusher-prop 21A, were characterized by their extended nose gear assembly.

It was not without a tradeoff, however: How could the pilot bail out without encountering that pusher prop? Saab engineers solved this with one of the first applications of an aircraft ejector seat.

The first production 21A fighters were delivered in December 1945. Their performance was more than adequate for the era, with a maximum speed of 400 mph, a cruising speed of 300 mph, a landing speed of 90 mph and a climb rate of 50 ft./sec. Not quite the performance of a North American P-51 Mustang, but not far off the pace either. Saab produced 298 21A variants between 1945 and 1948.

Variations on a theme, only here the variations make a radical jump from prop to jet. Images from Profile Publications Number 138 The Saab 21A & R. 

By the mid-1940s, though, everyone recognized that jets were the hot tip. (Agg! A propulsion pun.) In the autumn of 1945, Saab engineers undertook conversion of the 21A to de Havilland Goblin jet power.

The plan was to retain 80 percent of the prop version’s airframe, but this proved optimistic. The Goblin’s air intakes had to be incorporated. To avoid jet blast, the tail layout needed to be raised. Accommodating the jet’s thirst, all available space within the fuselage was devoted to fuel storage.

This winter photo shows the 21R’s intake nacelle and elevated tail structure, both accommodating its de Havilland Goblin jet engine.

The first 21R flew in early 1947, its enhanced performance justifying this nontrivial reengineering. Maximum speed rose to 500 mph; cruising speed, to 435. The aircraft landed at 95 mph and had a climb rate of 56 ft./sec.

Profile Publications, individually or in collection, on aircraft as well as automobiles, are wonderful resources. Secondhand sources include Amazon.com and ABEBooks.com.

Observed Bo Widfeldt in Profile Publications Number 138, The Saab 21A & 21R, “the Saab 21R was by no means an unqualified success, but its design and construction provided unique experience which was of inestimable value to Saab in later projects.”

Saab celebrated its aircraft heritage with this emblem introduced in 1949 for its cars.

Indeed, counting four prototypes, only 64 of Saab’s 21R were produced, the last in 1951. By then, the company’s 29 “Tunnan” (Swedish: “barrel”) had begun its production run of 661 aircraft.

Saab’s clean-sheet jet fighter, the 29 “Tunnan.” Image by Gnolam.

To me, though, the stocky swept-wing conventionality of the Tunnan didn’t have the elegance, not to say the romance, of the Saab 21. ds

5 comments on “SAAB 21—WHERE’S MY PROP?

  1. Bill Urban
    September 17, 2012

    Elegant indeed. Say Dennis, how might that mid-engine moment of inertia impact handling? Any reference to Saab ejection seats can’t go by without a salute to Nils Bohlin. As a Saab ejection seat engineer in the 50s’ he would have had intimate knowledge of, and would have learned from, this earlier design. (I don’t know how old he was, perhaps he contributed.) He later enjoyed world acclaim as the inventor of the three point seat belt . . . except that by then Nils Bohlin was working for Volvo. Volvo research says that more than one million lives have been saved worldwide. Thank you Nils.

    An aside – I got my father to test drive a 1964 544, but I couldn’t convince him to buy it (probably like many back then, I think he was turned off by that “new fangled foreign seat belt contraption”. I later got my own, a used 1965 544 . . . a great car.

  2. simanaitissays
    September 17, 2012

    As with mid-engine cars, I suspect there’d be a low polar moment of inertia and, thus, high maneuverability (not to say twitchiness).
    What with the pre-WWI Farman, WWI Borel Monoplane and Spad A2 as well as WWII Bell Aircobra and Kyushu Shinden, there’s an evident “Where’s My Prop/Engine?” Part 2 in time.
    Agreed, thank you, Nils Bohlin. When I lived on St. Thomas I had a 122S station wagon and always thought highly of its seat belt arrangement. ds

  3. carmacarcounselor
    September 24, 2012

    I chuckled at the comment of devoting every cubic centimeter of available space for the fuel in the conversion to turbojet power. Dad was in aviation from day one of the Piper Cub, working at their Bradford, PA plant in the 30’s, hauling incomplete airframes out of the building as the plant burned, and flying newly minted planes from the Lock Haven plant to the field where they were certified (for which he had to have a test pilot’s license). He was the one who told me the recip pilot’s dis of jets, “As soon as you lift off, you already have two emergencies. You’re on fire and low on fuel.”

  4. simanaitissays
    September 24, 2012

    Love it!
    Two other aviation one-liners, both from recip pilots:
    “The purpose of the propeller is to keep the pilot cool. When it stops spinning, you get really hot!”
    and
    “Helicopters don’t really fly; they’re so ugly, the Earth repels them.” — This, from a retired airline captain whose daughter is named “Piper.”

  5. carmacarcounselor
    September 24, 2012

    I especially love the one about ‘copters. So true.

Leave a Reply to carmacarcounselor Cancel reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Information

This entry was posted on September 17, 2012 by in Vintage Aero and tagged , , , .
%d bloggers like this: