THE 456th FIGHTER INTERCEPTOR SQUADRON

THE PROTECTORS OF  S. A. C.

 

 

Convair TF-102A "Delta Dagger"

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(From T.O. 1F-102A-1) - The TF-102A is a two-place, side-by-side trainer version of the         F-102A and is designed for combat use, if conditions make such use necessary. The airplane is equipped with a radar fire control system and is powered by a J57-P-23 axial-flow turbojet engine with afterburner. The airplane is characterized by a large 60-degree delta wing and the absence of a conventional empennage. Later aircraft (S/N 56-2336 and on) are equipped with a modified wing (Case XX wing) which produces greater lift and increases performance. The Case XX wing may be distinguished from the wing on earlier airplanes (Case X wing) by the droop at the wing-tip. The delta wing is equipped with "elevons" which provide combination aileron and elevator action from conventional cockpit controls. All control surfaces are hydraulically actuated and incorporate and artificial feel system. The airplane is equipped with a pressurized cockpit and contains two ejection seats. Tricycle landing gear is utilized for takeoff and landing. The aft fuselage mounted speed brakes also serve as compartment doors for a drag chute. The six integral wing tanks are serviced by a single-point pressure refueling system and fuel usage is sequenced automatically to maintain desireable center of gravity.

TYPE
TF-102A
Number built/Converted
111
Remarks
Dual-cockpit trainer

SPECIFICATIONS - TF-102A (from T.O. 1F-102A-1)
Span: 38 ft. 1.6 in.
Length: 63 ft. 4.3 in. (including pitot boom)
Height: 21 ft. 2.25 in.
Tread: 14 ft. 2.25 in.
Weight: 28,978 lbs. to 32,104 lbs. based on various mission loading conditions.
Armament: 24 unguided 2.75 inch rockets and six guided missiles
Engine: One Pratt & Whitney J57-P-23A of 10,200 lbs. thrust at Military power and 16,000 lbs. thrust with afterburner
Crew: Two

PERFORMANCE
Maximum speed: 646 mph. at 38,000 ft.
Cruising speed: 452 knots (.79 true Mach number) at 40,000 ft. clean configuration on optimum maximum endurance profile.
Range: approximately 1,350 nautical miles using cruise-climb profile, two 230-gal. external drop tanks (dropped when empty), initial: 35,000 ft. final: 41,000 ft. at 32,104 lb. takeoff gross weight. at .80 Mach (460 knots TAS) in 3 hours with 15 minute time-to-climb allowance. (1,250 nm. in 2 hrs. 45 min. with 230 ext. tanks not dropped when empty or 960 nm. in 2 hrs. 7 min. with no ext. tanks.)
Service Ceiling: 55,000 ft.

PHOTOGRAPHS AND TEXT COURTESY OF THE AIR FORCE MUSEUM

 

TF-102A "Delta Dagger"

 

The TF-102A was a training version of the F-102A. It had a wider forward fuselage providing side by side cockpit seating for student and instructor. The requirements for the TF-102A were to provide a dual controlled trainer version of the F-102A interceptor to transition jet pilots to the intricately different delta wing airplane. Neither ADC nor the Air Training Command believed that this training could be provided with conventional type jet trainers.

The General Operational Requirement was for a dual controlled trainer version of the F-102A interceptor to transition jet pilots to the intricately different delta wing airplane. Neither ADC nor the Air Training Command believed that this training could be provided with conventional type jet trainers. Shortcomings of the then available T-33 and radar equipped B-25 trainers had been confirmed by the F-86D and F-94 transition training programs.

The Air Force authorized production of the TF-102A. However, because of the problems encountered with the basic F-102A design, initial procurement was delayed and further production postponed until the fate of the tactical program was determined.

A firm order for 20 TF-102As was placed on contract, with first delivery due in July 1955. This initial procurement. followed approval by the TF-102A Mockup Board of the side by side trainer nose configuration, presented by the Convair Fort Worth plant in January 1954. It was endorsed (in preference to the conventional tandem configuration) to simplify training, realizing that the extra weight of the new forward fuselage would probably hinder trainer performance.

The two-place TF-102A was identical to the F-102A aft of the cockpit section. It would also retain the F-102A's weapon capability.

In early 1955, following the December 1954 successful flight of the revised YF-102A, 28 additional trainers were ordered. The Air Force gave Convair a letter contract for 150 other TF-102As in December--1 month after the trainer's first flight. These planes were to be delivered between March and December 1957.

First Flight (Production Aircraft): 8 November 1955

The Air Force accepted the first TF-102A during the month it first flew and took delivery of a second production in December 1955--several months past the original deadline.

Extensive operational testing soon revealed that the TF-102A's large cockpit and canopy created a serious buffeting problem at high speed. A new cockpit configuration with a cut down canopy and revised windshield, flight tested in April 1956, did not prove to be the answer. Buffeting was somewhat reduced but at the expense of landing visibility, which had become less than marginal. The simplest solution was to revert to the trainer's original cockpit. The buffeting problems would be eliminated by adding vortex generators and an increased area vertical stabilizer to the aircraft fuselage. These structural modifications, successfully tested. with the third TF-102A accepted by the Air Force in June 1956, were introduced in all subsequent productions.

The TF 102A's initial buffeting problem caused the Air Force to stop Convair production. The Air Force released its hold order late in June 1956, after successful testing of the third TF-102A--a modified article, representative of subsequent productions. During the same period the Air Force also decided to reduce its TF-102A procurement and cut Convair's last order almost by half. Despite the reduction, Convair did not make up for the time lost. Final deliveries to the Air Force still lagged 6 months behind the original schedule.

Production ended in July 1958 with delivery of the last five TF-102As.

A total of 111 TF-102As were accepted (68 less than once programmed), bringing total F/TF-102A procurement to 1,000 aircraft.

Three TF 102As were accepted in FY 56, 27 in FY 57, 76 in FY 58, and 5 in FY 59.

Flyaway Cost Per Production Aircraft was: $1.5 million airframe, $1,135,018; engine (installed), $144,474; electronics, $11,365; armament, $173,777; ordnance, $1,192. These costs excluded $137,947 in prorated Class V modification costs and $11,182 spent on each TF-102A for specific modifications.

Average Cost Per Flying Hour $611.00

The TF-102A's phase out and operational life followed that of the F-102A's pattern. As a rule, two TF-102As accompanied each F-102A squadron.

 

Delta-winged aircraft have particular features which endow them with quite different handling characteristics than more conventional aircraft. Among these are a rather high angle of attack during takeoff and landing, and a high induced drag during turning. In order for pilots used to such aircraft as the Northrop F-89 Scorpion and the North American F-86D Sabre to be able safely to transition to the delta-winged F-102A, the Air Force thought that a two-seat trainer version of the Delta Dagger was necessary. The TF-102A two-seat combat trainer was evolved to meet this need.

Work on the two-seat Delta Dagger was done under the aegis of Weapons System WS-201L. The initial authorization of the TF-102A was on September 16, 1953. At that time, problems were still being experienced with the single seat YF-102, and further procurement of the TF-102A was deferred until these difficulties could be ironed out.

In July of 1954, an initial order for 20 TF-102As was placed, with first delivery to be in July of 1955. The TF-102A had a wider forward fuselage that seated two crew members in a side-by-side configuration. The side-by-side seating arrangement was preferred over the usual tandem seating arrangement, in the belief that it would simply inflight training, even in spite of the fact that the broader cockpit would probably have an adverse affect on performance. Because of the new wider cockpit, the lateral air intakes had to be reconfigured. They were reshaped and mounted down lower on the fuselage than on the F-102A. The rest of the airframe was otherwise identical to that of the single-seat F-102A, and the same weapons suite could be carried. However, the Hughes MG-10 fire control system was not fitted.

A mockup of the nose section was inspected in September of 1954. In early 1955, following the successful testing of the revised YF-102A, the Air Force ordered 28 more TF-102As.

The first TF-102A (company Model 8-12) flew on October 31, 1955, with Richard L. Johnson at the controls. It was a brief hop that was cut short because of a faulty canopy seal. A month later, the Air Force gave Convair a letter contract for 150 more TF-102As

Initial testing indicated that the TF-102A's bulbous cockpit created a severe buffeting problem at high speed. A new cockpit configuration with a cut-down canopy and revised windshield was tested in April of 1956 but it did not seem to help very much. Buffeting was reduced somewhat, but only at the expense of a much poorer landing visibility. Since the aircraft was basically a trainer rather than a combat aircraft, it was felt that visibility had to be favored over speed and the original cockpit design was restored. The buffeting problem was largely cured by adding a set of vortex generators on the cockpit canopy framing in order to provide smooth airflow over the cockpit. In addition, the vertical tail was increased in area. These changes were introduced with the third TF-102A to be accepted by the USAF and were adopted as standard.

Although 111 TF-102As were ordered, only 63 were actually produced. Each F-102A squadron normally included two TF-102A two-seaters on strength.

Some TF-102A two-seaters were used on occasion in Vietnam as forward air controllers.

The TF-102A was powered by a Pratt & Whitney J57-P-23 turbojet, rated at 11,700 lb.s.t dry and 17,200 lb.s.t with afterburning. The TF-102A was incapable of supersonic performance in level flight, but could exceed the speed of sound in a shallow dive. Maximum speed was 646 mph at 38,000 feet (Mach 0.97). An altitude of 32,800 feet could be attained in 2 minutes 50 seconds. Ceiling was 50,000 feet. Normal loaded weight was 27,778 pounds. Dimensions were wingspan 38 feet 1 1/2 inches, length 63 feet 4 1/2 inches, height 20 feet 7 inches, wing area 661.5 square feet.

 

Serials of the TF-102A:

54-1351/1354	Convair TF-102A-5-CO Delta Dagger
54-1355/1359	Convair TF-102A-10-CO Delta Dagger
			1356,1358,1359 converted to NTF-102A.
54-1360	Convair TF-102A-35-CO Delta Dagger
			to Turkey.
54-1361/1365	Convair TF-102A-15-CO Delta Dagger
54-1366/1368	Convair TF-102A-20-CO Delta Dagger
54-1369/1370	Convair TF-102A-25-CO Delta Dagger
55-4032/4034	Convair TF-102A-26-CO Delta Dagger
			4033 sold to Turkey.	
55-4035/4042	Convair TF-102A-30-CO Delta Dagger
			4035 sold to Greece.
55-4043/4050	Convair TF-102A-35-CO Delta Dagger
55-4051/4056	Convair TF-102A-36-CO Delta Dagger
			4053 sold to Turkey.
55-4057/4059	Convair TF-102A-37-CO Delta Dagger
56-2317/2323	Convair TF-102A-38-CO Delta Dagger
56-2324/2335	Convair TF-102A-40-CO Delta Dagger
			2325 sold to Turkey
			2326,2327,2334,2335 sold to Greece
56-2336/2353	Convair TF-102A-41-CO Delta Dagger
			2342 sold to Turkey
56-2354/2379	Convair TF-102A-45-CO Delta Dagger
			2355,2368 sold to Turkey
56-2380/2466	Cancelled contract for Convair TF-102A Delta Dagger

Joe Baugher

Sources:

  1. General Dynamics Aircraft and their Predecessors, John Wegg, Naval Institute Press, 1990.
     
  2. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.
     
  3. The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.
     
  4. Fighters of the United States Air Force, Robert F. Dorr and David Donald, Temple Press Aerospace, 1990.
     
  5. American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday, 1982.
     
  6. Post-World War II Fighters, 1945-1973, Marcelle Size Knaack, Office of Air Force History, 1986.
     
  7. The World Guide to Combat Planes, William Green, MacDonald, London, 1966
     
  8. The World's Fighting Planes, William Green, Doubleday, 1964.
     
  9. The Aircraft of the World, William Green and Gerald Pollinger, Doubleday, 1965.
     
  10. E-mail from Raymond Puffer with correction on date of first flight of TF-102A. A lot of references list the first flight date as November 8, 1955, but official documents and test pilot Dick Johnson list it as Oct 31, 1955.

 

 

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