Apr 9

Fightdeck Friday: Of Afterburners and Balsawood

Friday, April 9, 2010 12:09 AM

The Navy's First Jets -- Front: Vought F6U-1 Pirate (McDonnel FH Phantom and F2H Banshee in background)

Certain pairings, on the surface, seem to be made for each other – Bogie & Bacall, rum & Coke ®, etc. But balsa wood and afterburners? Almost seems counter-intuitive.

So of course – ecce, this weeks feature: the Vought F6U Pirate, the Navy’s first composite-built and afterburner fighter.

Westinghouse J34

By 1944 it was apparent from the reports being returned from the European theater of ops that the future lay in jets and the Navy soon joined the fray. In September 1944, BuAer (Bureau of Aeronautics) issued a specification for a single seat fighter to be powered by the Westinghouse J34 turbojet. As was the case for American jet engines of the time, Westinghouse power plants were notoriously underpowered, with the J40 in particular being the death knell for otherwise good designs. The J34 was part and parcel of that trend, mustering a mere 3K lbs of thrust (and that was doubling the predecessor J30’s output). Besides Vought, North American Aviation and McDonnell were invited to the competition. McDonnell would use two J34s and North American adapted the larger Allison J35 turbojet (both of these will be future Flightdeck Friday subjects).

With such miniscule power available, weight saving measures were the order of the day and Vought evidently thought they had a solution in the form of their “Metalite” and “Fabrilite” materials. The former consisted of a sandwich of balsa wood between two thin aluminum sheets and would be used for most of the structure. The latter consisted of a fiberglass sandwich with a balsa wood core and was used for the vertical tail surfaces and inlet (see, the Hornet wasn’t the first plastic jet).

Alas, as inspired as the material solution might have been, the aircraft itself was, well, as underwhelming as its thrust. Looking much like a fat sausage with wings and empennage stuck on as an afterthought, the Pirate tipped the scales at just over 7,000 lbs. Empty. Gross was over 12K. Paint it pink and it probably would have been a suitable prop for a Pink Floyd concert…

The F6U encountered a number of problems during development – in flight and on the ground. In the air, the under-performance of the J34 only underscored handling problems that were traced to poor design of the tail surfaces. In an attempt to boost speed, an afterburner was developed and grafted to the fuselage (the singular contribution of the F6U to modern jet design). The lengthened fuselage required re-balancing which was accomplished with a minor increase in internal fuel carriage.

That extra fuel was a necessity, for while the afterburner may have kicked output up to over 4,000 lbs of thrust, if left in a/b the Pirate would run out of fuel in less than 15 minutes. Still, the a/b moved airspeed up past 400 knots, where an unacceptable dutch roll was encountered – again traced to the tail design. It was in the midst of this design crisis that Connecticut-based Vought decided new production facilities were required closer to the test facility at Muroc Lake (the future Edwards AFB). That prompted move to Fort Worth, Texas – a move many Vought employees declined to make. The move, combined with attendant delays due to airframe re-designs and delays in government supplied equipment ensured the Pirate would end up being the last of the three to reach the Fleet.

Except that it never made it there. Three prototypes and 30 production aircraft were ordered, but only two aircraft delivered by October 1949 – at which point the other two manufacturers were delivering the next iteration of their fighters to the Fleet. Carrier trials were never scheduled as production aircraft were shunted off to VX-3 while their future was puzzled out. That future proved to be short-lived when BuAer (mercifully) euthanized the program in 1950, stating in the wrap-up report that:

“The F6U-1 had proven so sub-marginal in performance that combat utilization is not feasible.”

The collective production aircraft had flown less than 1,000 hours. For some, all they saw were the initial acceptance flights before being placed in preservation.

Where are they now? Most ended up as fodder on weapons ranges in the southwest US, but one remains and is now under going restoration at the Vought plant in Grand Prairie, Texas. The aircraft was transferred from the New England Air Museum to Vought on October 2002.


General characteristics

  • Crew: 1
  • Length: 37 ft 7 in (11.46 m)
  • Wingspan: 32 ft 10 in (10 m)
  • Height: 12 ft 11 in (3.39 m)
  • Wing area: 203.4 ft² (18.9 m²)
  • Empty weight: 7,320 lb (3,320 kg)
  • Loaded weight: 12,900 lb (5,850 kg)
  • Powerplant: 1× Westinghouse J34-WE-30A turbojet
    • Dry thrust: 3,150 lbf (14.0 kN)
    • Thrust with afterburner: 4,224 lbf (18.78 kN)

Performance

  • Maximum speed: 596 mph (517 kn, 959 km/h)
  • Range: 1,170 mi (1,020 nmi, 1,880 km)
  • Service ceiling: 46,260 ft (14,100 m)
  • Rate of climb: 8,060 ft/min (40.95 m/s)
  • Wing loading: 63.4 lb/ft² (304 kg/m²)
  • Thrust/weight: 0.327

Armament

  • Guns: 4 × 20 mm (0.79 in) M3 cannon under the nose

Data from The Complete Book of Fighters

Sources:

Green, William and Gordon Swanborough. The Complete Book of Fighters. New York: Barnes & Noble Inc., 1988

Swanborough, Gordon and Bowers, Peter M. United States Navy Aircraft since 1911, Third Edition. Naval Institute Press, 1968

Thomason, Tommy H. U.S. Naval Air Superiority: Development of Shipborne Jet Fighters 1943-1962. Specialty Press, North Branch, MN 2007

Next week — is there a FORD in our future?

 
 
 
  • Jim Dolbow

    Great Photos as always SJS! Flightdeck Friday is about the only good thing on Friday given my work schedule of Friday being my monday.

  • Quarters

    First time reader. Wow, just when I thought I knew everything about naval aviation. Great job.

  • http://steeljawscribe.com/ SteelJawScribe

    Thanks guys — the fun is just beginning. Neat stuff coming next week for the F4D’s…
    w/r, SJS

  • http://nymas.org Tom Wisker

    Interesting in the extreme. Didn’t realize she was THAT much of a dog. With that mode of construction, structural/battle damage repairs would have been a nightmare, especially at sea. Oh, well… live and learn.
    –Tom Wisker WEAPONRY on WBAI-FM / wbai.org for podcast/archive.