Saab 35 Draken, an overview (original) (raw)

Contents:

Background

Draken means The Dragon.

The project "1200" to find a replacement for Saab 29 Tunnan ("Flying Barrel") started in 1949. It was intended to be an interceptor able to counter bombers flying at M 0.9 at high altitudes and thus had to be supersonic.

To test the double delta that was a combination of a delta and thin swept wing, construction of aa small concept aircraft, Saab 210, was started in May 1950. It flew for the first time 21:st Jan 1952. (It made a 1 s small hop in Dec 1951, by mistake.) This proved to be a layout that combined good high speed properties with a low enough take off and landing speed.

Intended engine for Draken was the Swedish STAL Glan, whose design was never finished, but in 1952 it was decided to go for Rolls-Royce Avons instead.

In Jan 1953 the air force ordered three prototype and three series aircraft of type "35". The first prototype flew first on 25:th Oct 1955. Its engine was a RR Avon Mk.21 (RM5A in Sweden) without an afterburner.

[[J 35D on the flight line]](/web/20120316071650/http://www.x-plane.org/home/urf/aviation/img/lule77/j35d-03.jpg)Even though speed and good climbing performace was the priority, the aircraft later showed itself to be good dogfighter too. Its instantaneous turn rate is very good, but as is typical for delta winged aircraft, induced drag bleeds off a lot of energy during turns.

In order to enable it to operate from partially damaged runways and stretches of highway, it was given a brake chute to decrease the landing run.

Emphasis was placed on the ability to be serviced quickly by conscripts with relatively short training. A team of seven, of which six conscripts, are supposed to be able to re-arm and re-fuel an aircraft in less than 10 min.

Emergency power is supplied by a ram air turbine just behind the nose gear, extended either on hydraulic power failure, or on manual command. Can only be retracted with the engine running.

The seat is angled back 30 degrees.

Designations:

J, Jakt = Fighter/interceptor Sk, Skol = Trainer S, Spaning = Reconnaissance

Swedish air force versions

J 35A

designation number delivered in service serial numbers J 35A short 65 1960-61 -1976 35001-35065

RM6B (= RR Avon Mk.48A) with afterburner "type 65" Delivered without radar nor sights. Later given Thomson-CSF Cyrano radar. While unarmed, they served a single seat trainers, both for pilots and ground crews.

J 35A long 25 1960-61 -1976 35066-35090

Longer afterburner , "type 66" to increase max altitude, otherwise as A short.

Remaining A:s equipped with undernose IR-detectors (not the same as the F:s had) in 1966-67.

J 35B

J 35B1 72 1962-63 35202-35273

Delivered without radars, 69 konverted into J 35B during 1964-65. Weapons as "A" variant. Engine as "A long"

J 35B 69 1964-65 -1976

Zero altitude (but not zero speed) rocket seat. Improved control system.

Sk 35C

Sk 35C 25 1962-63 -> 35801-35825

[[Two seat Draken]](/web/20120316071650/http://www.x-plane.org/home/urf/aviation/img/karlsborg79/sk35%5F16-73.jpg)Two-seat trainers, rebuilt from J 35A short with same engines.

At first it was thought that a trainer version would not be needed, as the company test pilots considered it easy to fly. Most air force pilots didn't agree.

As we have a long term commitment to train Austrian pilots, the last 5 in service may remain after Draken is retired as a fighter.

J 35D

J 35D1 block 1 30 1963 35275-35304

RM6C (=RR Avon Mk.60) with afterburner "type 67". Required the air intakes extended further forward.

Delivered without radars. In storage most of the time until 1966.

J 35D1 block 2 24 1964 35305-35328 J 35D2 block 3 66 1964-65 35329-35393

First variant to have rocket seat (0 altitude, 100 km/h) as newbuilt. (Aircraft of all variants remaining in service later got "generation 2" seats.)

J 35D 120 -1968 -1984 35274-35393

D1 and D2 designations abolished when all D1:s rebuilt into D2 standard.

The D variant was first thought of as B2. It has a more powerful engine, so air intakes extend further forward; 600 litres larger internal fuel capacity as well as two 530 litre external tanks.

S 35E

S 35E 30 1965-66 -1981 35902-35931 S 35E 29 1966-68 -1981 35932-35960

Rebuilt J 35D1 block 1, retaing the 'older' style canopy, the first 30 had the 'F-style' canopy.

3 SKa 24-600 long focal length cameras, one in the nose, two in place of the guns; one forward facing SKa 16B, one downward looking wide angle Ska 24-44 and two sidelooking SKa 24-100 all in the nose, all made by OMERA/Segid in France. Engine as "D".

*Some photos, with captions, of the cockpit.

J 35F

J 35F1 230 1965-72 -1989? 35401-35630 J 35F2 above includes F2

F2 was fitted with Hughes S-71N (AN/AAR-4) IR-detectors from the beginning, F1:s never had one.

J 35J

J 35J 66 1987-91 -1998

Extensively rebuilt J 35F:s. In March 1997 the strength was down to a single squadron, with 22 aircraft. The last batch of four pilots started their training on the type in 1997. Last scheduled flight was 1998 Dec 08.

Prototypes

"Missing" serials are mostly aircraft retained by the manufacturer.

There were 13 (*) prototypes, of which at least the first five were originals, the rest were probably converted series aircraft. No serials officially available for F and J, as they are still in service. (*) 14 if you count the demonstration aircraft J 35H (Helvetica), so total number produced in 1954-1989 is 612.

Armament options

     |              Weapons options. All later variants can carry
     |              all external weapons earlier can.
  _  n  _

-----<_>(.)<_>----- Built in: 2 x 30 mm Aden guns with 150 rounds each

3 241 7 656 7 142 3 Pylon numbering, 7 only on J 35J, 6 on versions D-J. 1,2,3 only for ground attack rockets or photo bombs. 4 and 6 (or 4 and 5 with a Y pylon) for missiles (4,6 and 7 on J). Tanks on 5 (single) or 6. 2 4 3 1 Firing order for missiles 1 2 2 1 (if a single type).

1210 8 7 9 11 Firing order for rockets, also 6 4 2 1 3 5 in pairs like missiles (above).

J 35A "short" T 530 litre external tank 24 24 24 24 4 x Rb 24 (Sidewinder), firably singly or in pairs Inverted "Y" pylon under centre fuselage.

J 35A "long" rrr rrr 12 x 135 mm rockets for ground attack rrr rrr

J 35B R R 2 pods of M57 19 x 75mm anti-aircraft rockets. Launched as a single salvo.

Sk 35 C Is a totally unarmed trainer.

J 35D Has the "Y" pylon replaced with two separate. T T 2 x 530 litre tanks.

S 35E Is an unarmed reconnaissance version T T T T 4 x 530 litre tanks iii iii 6 x 80 kg magnesium flash bombs. KB BOX-9 chaff/flare dispenser MSK Night recce pod, IR film cameras and electronic flashes.

J 35F Left gun removed to make space for electronics. 28 28 28 28 More missile types: Rb 27, Rb 28 and Rb 24/24J 27 27 27 27 24 24 24 24 Rb 24/24J R R Note that the rocket pods can only be used for air-to-ground. 28 27 27 28 Other 27 24 24 27 possible 28 27 24 28 missile combinations

J 35J has wing pylons wet; extra pylons under forward wings. 24 24 24 24 24 24 Sidewinder 28 28 28 28 Falcon, IR 27 27 27 27 Falcon, SAR R R R R 19 x 75 mm anti-aircraft rockets, now again for anti-aircraft T T T T 4 x 530 litre tanks.

EXPORTS

Finland

Saab 35BS 6 Reworked J 35B Saab 35F 24 Secondhand Sk 35C 5 Secondhand Saab 35XS 12 Almost as J 35F, built in Finland 351301-351312 Upgraded to more or less J 35J standard, but with what seem to be a more extensive countermeasures suit.

The last squadron will be retired in 2000.

Saab J 35 Draken A Finnish Draken document (in Finnish, but with photos).

Finnish Air Force Draken page.

Denmark (Saab 35XD)

Denmark started planning for two squadrons of RF-84F and F-100 replacement in 1966. The candidates were A-4F Skyhawk, F-5A, A-7 Corsair, F-104-CL 984 Starfighter, Mirage 5 and Draken. Quickly F-5 and Mirage 5 were shortlisted. Draken was out of the question due to payload/range, since it after all wouldn't serve as an interceptor (which if you believe some accounts came as a surprise to Saab). Anyway, this led to a 180 000 manhour redesign work to create 35XD with 35F as a basis -- whereupon the type was put on the new shortlist.

The main changes were

Draken won due to it being preferred by the air force for operational and economic reasons and the government financially and trade politically. The first ones were delivered in 1971.

In 1970-71 they were interested in purchasing 23-46 more for one or two more squadrons. Among the possibilities then were a new Ericsson radar, SAX-500, new avionics and BT 9 sights. And also economy variants like refurbished J 35Fs to be called J 35FD H�G with new avionics were suggested. But budget cuts affected the size of the air force too, from 7 to four squadrons, so there were no purchases.

In Danish service they were upgraded several times. Early on they got a new altimeter and ALR-45 RWR. In the late 1970's they got four chaff and flare launchers.

During the 1980's they got a new WDNS (weapon delivery and navigation system), which meant a new radar altimeter, HUD in the cockpit, ALR-69 RWR (six antennas on the fin, two on each wingtip and two under the nose), laser rangefinder in the nose and ALQ-162 EW pods under the wing. The last one, of 43, so updated was finished in 1986.

F-35 20 Delivered with plain nose, later given laser 351001-351020 rangers, so they look a lot like RF-35s
RF-35 20 Reconnaissance, cameras in nose similar 351101-351120 TF-35 11 Two-seat trainer 351151-351161 Higher gross weight than Swedish versions, due to more internal fuel.

Draken served in the Danish air force until 1993.

One TF-35 is in Sweden at Flygvapenmuseum, one TF-35 and one RF-35 were handed over to Scandinavian Historic Flight, and six were sold to National Test Pilot School in USA where currently (2000) three are kept in flying condition.

Most of the 1275 litre tanks have been bought back by Saab and reused (after some minor modifications) on JAS 39 Gripen.

Austria

Saab 35OE 24 Reworked J 35Ds.

Armament at first consisted only of two 30 mm Aden guns, but later on AIM-9P3 Sidewinder missiles were purchased from Saab and AIM-9P5s may be or might already have been purchased.

Austrian Air Force Saab 35OE Draken page.

Other exports

There were no other exports, unless you count museum examples and aircraft used in trade to get museum examples to Sweden. But you can read about thefailed export efforts.

Technical data

Data for J 35J Empty weight: 7400 kg Internal fuel: 2865 l External fuel: 4 x 525 l Max load: 2200 kg Max take off weight: 12400 kg Engine thrust: 5845 kp; 7880 kp with afterburner (RM 6C) Max speed: Mach 2.0 Range: 2000+ km Take off run: 790 m (1195 m without afterburner) Landing run: 880 m (1220 m without brake chute) Length: 15.34 m Span: 9.42 m Height: 3.89 m Wing area: 49 m^2 Max wing loading: 253 kg/m^2

Data for J 35D Empty weight: 7265 kg Internal fuel: 2920 l External fuel: 2 x 525 l Max load: 2200 kg Max take off weight: 11864 kg Engine thrust: 5845 kp; 7880 kp with afterburner (RM 6C) Max speed: 2150 km/h Take off run: 774 m (1175 m without afterburner) Landing run: 678 m (920 m without brake chute)

Data for J 35A, short Empty weight: 6590 kg Internal fuel: 2240 l External fuel: 1 x 525 l Max load: 1700 kg Max take off weight: 10089 kg Engine thrust: 4890 kp; 6520 kp with afterburner (RM 6B) Max speed: 1900 km/h Take off run: 413 m (701 m without afterburner) Landing run: 510 m (810 m without brake chute)

Data for variants J 35A short - S 35E: Length: 15.21 - 15.34 m, Span: 9.4 m, Height: 3.87 - 3.9 m, Wing area: 49 m^2, Max wing loading: 202 - 240 kg/m^2

The Danish F/RF/TF-35s had completely redesigned outer wings with slightly larger span, and more pylons, 1275 litre external tanks and are thus quite heavier, beeing primarily ground attack aircraft. They were fitted with two 30 mm Aden guns, external loads were carried on two pylons under each outer wing, one under the forward wing and three under the fuselage. Weapons included AIM-9B and AIM-9N-3 Sidewinder, AGM-12B Bullpup, free fall bombs and rocket pods.

Empty weight: 7500 kg Internal fuel: 4034 l External fuel: 2 x 1275 l Max load: 4500 kg Max take off weight: 16000 kg Max speed: Mach 2.0 Range: 3000 km

Projected variants

Before it was decided to develop a fighter version of Viggen there were studies, including wind tunnel, of a variant with a larger nose for a more powerful radar and IR seeker to be designated JA 35. This had plenty more drag and less yaw stability. In 1969 development of JA 37 Viggen was given a go ahead, so JA 35 Draken was cancelled.

There were also studies which aimed towards increasing the pitch stability at low speeds and yaw stability at all speeds, supersonic turn performance and acceleration by diverse aerodynamic refinements, more powerful engine, more powerful control surface actuator and/or an improved FCS.

In 1971, in connection with the Danish export drive, there were plans for a variant called AS 35X which would have been given a needle point nose, larger outer wings with dogtooths and a GE J79/J1S engine.

In the 1980's, before Gripen was decided on, there were plans on remanufacturing Drakens to let them serve as interim ground attack fighters before a replacement for AJ 37 Viggen was choosen and delivered. (In the event it turned out that the Viggens had more airframe life left than thought and Gripen was ordered.)

What was required was mainly BAS 90 compatibility, at least some improved ground attack capability, hopefully including RBS 15 and a rather higher landing weight.

The minimal change to Draken, 35 MOD level 1b, would consist of new pylons (actually the ones which were fitted to J 35J, as a result of these studies), partly new avionics, larger brake chute and new wheels and brakes.

The most extensive AJ 35 Draken upgrade, 35 MOD level 4, would have consisted of new outer wings giving a 1 m greater span with small dogtooths, a fin extension, additional elevon actuators and some kind of canards -- most likely flip out moustaches on the sides of the air intakes. Clearance between the RBS 15F fins under the front wings and the ground would have been 44 mm.

The load out could have consisted of 2 x RBS 15F under the front wings, 2 x tanks under the fuselage the countermeasures pods U22 and KB (as on Viggen) and outboard of them Sidewinders or RB 28 Falcons under the outer wings. It would have retained the one built in 30 mm gun and also be capable of carrying Mavericks and the 6 x 135 mm rocket pods.

Data for AJ 35 level 4 Length: 15.34 m Span: 10.56 m Height: 4.09 m Wing area: 54 m^2 Internal fuel: 2745 kg External fuel: 2 x 525 l Take off weight: 11800 kg Max take off weight: 14800 kg Engine thrust: 5845 kp; 7880 kp with afterburner (RM 6C) Take off run: 750 m Landing run: 600 m (800 m without brake chute) Radius, lo-lo-lo 303 km

External sites

Military aviation
Main text of document written in 1993, put on the web in 1994, then modified extensively in Dec 1998, last updated 2006 Oct 25by Urban Fredriksson

griffon@canit.se