De Havilland DH.127 and DH.128

[steelpillow]

According to Derek Wood; Project Cancelled, pp.190, 192-195, the DH.127 was a two-seat V/STOL strike/reconnaissance aircraft with high-mounted delta wing, twin reheated Speys and two lift engines in front of the cockpit. Joint RAF/RN requirement OR.346 led to Ministry Specification ER.206 for an associated research aircraft, and it was for this that the DH.127 was submitted. (The other contender was the Vickers-Armstrong Type 581 variable-geometry design, heavily influenced by the work of Barnes Wallis). According to the linked Type 581 thread, the year was 1959.

Detailed features of the DH.127 included thrust-vectoring nozzles near the front of the Speys, apparently bleeding off cold air from the compressor, Mirage-style semicircular intake shock cones, folding wing tips, drop tanks and arrester hook. Its multipurpose weapons bay could accommodate a small nuke. Judging by its size relative to the Speys it was a fraction smaller than the Mirage IV and one could be forgiven for thinking it a V/STOL variant of the Dassault bomber.

The DH.128 was later submitted as a specifically naval design, in competition with the similarly revised BAC (as Vickers had now become) 535 VG proposal.

 

[blackkite]

De Havilland DH-127

Projet de chasseur bombardier ADAV supersonique britannique des années 1960.

www.aviationsmilitaires.net

The British manufacturer de Havilland studied the DH.127 from 1961 to respond to the OR.346, which claimed a supersonic vertical take-off fighter-bomber capable of operating from the deck of an aircraft carrier. This aircraft, which is designed to operate from Ark Royal vessels, is a two-seater in tandem. Its Delta wings are in a high position with a slight negative dihedral. Large driftish, but the device is devoid of horizontal tailings. The tricycle landing gear slips into the fuselage. Two semi-circular air intakes with mobile mice on either side of the fuselage power the two Rolls-Royce RB.198 Spey turbojets installed side-by-side at the rear of the airframe. These engines are equipped with jet deviators to direct the flow downwards during the take-off, landing and hovering phases. To ensure sufficient sustenance, two other RB.162 engines are installed at the front of the cockpit in the nose. The large one can also house a search and navigation radar. A ventral cargo hold can carry most of the planned armaments.

Originally intended for bombing missions, the DH.127 is equipped with large fuel tanks. Its range is 1,579km with a 907kg nuclear bomb, or even 2,780km with additional tanks under the wings. It can also carry 8 454kg bombs, four of which are in the cargo hold and the others under the wings, at 1'668km. Its cruising speed would be Mach 0.9 in these different configurations.

For air-to-air missions, the DH.127 can carry four Red-Top air-to-air missiles, or possibly its successor. It can be quickly equipped in this way and, by taking off on alert, it should be able to intercept a target flying at Mach3 at 24,000m 185km from the aircraft carrier from which it took off. In the event of an air patrol, it may cross for up to 4 hours near the aircraft carrier.

Following various modifications, the device is redesignated DH.128. De Havilland is also working on TV-guided air-to-ground missiles that would reduce the vulnerability of bombers while increasing the accuracy of strikes.

With the launch of the NBMR.3 (NATO Basic Military Requirement 3) project, the government is asking the Navy to search for a joint aircraft with the RAF. The P.1154 is preferred to others but does not satisfy the Navy which decides to go it alone, but it is already too late for the project DH.127/DH.128 which is definitely abandoned.

Text by Jericho, created on 2019 -516 -22:16, edited on 2020-2-26:03. ©Military Aviation

 

[blackkite]

Key features
Maximum take-off mass: 25,402 kg (56,002 lbs)
Area: 52.1 m2 (560.8 sq. ft)
Wingspan: 10.1 m (33.136 ft)
Length: 18.3 m (60,039 ft)

Performance
Take-off distance: 0 m (0 ft)
Landing distance: 0 m (0 ft)
Maximum cruising speed: Mach 0.9
Range: 1,668 km (1,036 mi, 901 nm) with internal fuel
Range: 2,780 km (1,727 mi, 1,501 nm) with max fuel (internal-external)
Maximum SPEED HA: Mach 2.5
Load at take-off: 487,562 kg/m2 (99,861 lbs/sq. ft)

Motorization
2 Rolls-Royce RB.198 Spey engines
Unit power: 5,015,291 kgp (49.2 kN, 11,056,832 lbf), 8,450,561 kgp (82.9 kN, 18,630,312 lbf) with post-combustion
2 Rolls-Royce RB.162 engines
Unit power: 1,600 kgp (16 kN, 3,527 lbf)

Text by Jericho, created on 2019 -516 -22:16, edited on 2020-2-26:03. ©Military Aviation

 

[steelpillow]

They also have an extended specification:

Description:
Delta wing, High wing, Monoplane, Arrow type, Tailless, Rounded side air intakes, 4 engines, Closed cockpit
Characteristics

Maximum takeoff weight: 25,402 kg (56,002 lbs)
Wing area: 52.1 m² (560.8 sq. ft)
Wingspan: 10.1 m (33,136 ft)
Length: 18.3 m (60,039 ft)

Performance:
Take-off distance: 0 m (0 ft)
Landing distance: 0 m (0 ft)
Max cruising speed: Mach 0.9
Range: 1,668 km (1,036 mi, 901 nm) on internal fuel
Range: 2,780 km (1,727 mi, 1,501 nm) with drop tanks
Maximum speed HA: Mach 2.5
Thrust/weight ratio, on takeoff: 0.52
Thrust/weight ratio, on takeoff, with PC: 0.67
Wing load, on takeoff: 487,562 kg / m² (99,861 lbs / sq. ft)

Crew:
Crew: 2

Engines:
2 Rolls-Royce RB.198 Spey
Power ea.: 5,015.291 kgp (49.2 kN, 11,056.832 lbf), 8,450.561 kgp (82.9 kN, 18,630.312 lbf) with reheat
2 Rolls-Royce RB.162 lift engines
Power ea.: 1,600 kgp (16 kN, 3,527 lbf)
Fuel (max: internal + external): 19,915 l (5,261 US Gal., 4,381 UK Gal.)
Fuel (internal): 10,867 l (2,871 US Gal., 2,390 UK Gal.)

 

[steelpillow]

This image has a lot of detail in common with the one in Wood but the GA is laid out differently, I wonder if one is derived from the other.

Model Flying

www.modelflying.co.uk

 

[blackkite]

Oh super!! Thanks a lot.
This engine is very impressive. Was there a switching device for vectored nozzle and A/B?

 

[archipeppe]

Wow a sort of English Mirage III/IV/Balzac/F1 merging!!

 

[steelpillow]

Interesting to compare it with the Mirage IV:

	DH.127	Mirage IV
Length	18.3 m (60 ft 0 in)	23.49 m (77 ft 1 in)
Span	10.1 m (33 ft 2 in)	11.85 m (38 ft 11 in)
Area	52.1 m² (561 sq. ft)	78 m² (840 sq ft)

Range is comparable, the DH payload is around half that of the Mirage. Considering the DH is V/STOL, that is pretty impressive.

TSR-2 was longer and with twice the range, and almost contemporary, so there must have been some friction between the two requirements/projects. The Mirage IV similarity comes to the fore when we recall that following cancellation of TSR-2, BAC and Dassault tried to get the government interested in a "Spey Mirage", with the UK engines and avionics stuffed into a bigger fuselage, dubbed (by some?) the Mirage IVK.

 

[steelpillow]

Oh super!! Thanks a lot.
This engine is very impressive. Was there a switching device for vectored nozzle and A/B?

I have found no more than is on the drawings. The drawing in Woods has a little more detail visible.
It looks as if the side nozzles take cold air bled from the compressor exhaust, are angled down a fair bit, presumably with vertical deflector/guide vanes, and are fully recessed. A flap like an airbrake opens during STOVL operation and closes over the nozzle in forward flight. Or, to put it another way, the side nozzles are tucked in under the airbrakes - neat.
There are some odd textures to the fairings under the main nozzles, so I guess but it is not clear whether those can deflect down a fair bit as well.

 

[blackkite]

Thanks a lot. Anyway DH.127 was a twin engine aircraft.

Picture source : SPF

https://www.secretprojects.co.uk/threads/rolls-royce-liftjets-from-rb82-to-xj-99.2069/

 

[steelpillow]

Interesting. Not the RB198, but these do highlight a mistake I just made.
The main engine is in fact in front of the side nozzle and everything further back is afterburner and thrust deflection. So that's hot exhaust coming out the side. I have made some corrections to my earlier posts.

But technically the DH.127 is four-engined: the other two are lift engines in the nose.

 

[blackkite]

You are absolutely right.

 

[VictorXL188]

Further to the comments about the GA drawing in Project Cancelled, here's that one for comparison

 

[Archibald]

As for "seeing the light" about lift jets: think of the MiG-23 and Su-24 early iterations and prototypes. They both started as typical 1960's VSTOL complicated monstrosities. Then the Soviets saw the light - ditched the lift jets and turned them into the familiar MiG-23 and Su-24., both very reasonably successfull and long lived.

So - it can be done !

You know what would be great ? switch to just one BS-100. No more lift jets (bleh !) yet still VSTOL: with massive power to spare. BS-100 was the great missed opportunity of the TSR-2 / HS.681 / P.1154 cancellations.

 

[Arjen]

the MiG-23 and Su-24 early iterations and prototypes. They both started as typical 1960's VSTOL complicated monstrosities.

Not VSTOL.

Lift jets were the initial solution for achieving STOL ability in what became MiG-23 and Su-24. The lift jet-equipped prototypes lacked swing wings. In a thorough redesign, lift jets were removed, swing wings introduced to achieve STOL ability.

 

[Archibald]

Fair enough. My hatred for "lift jets = Harry Potter magical lift devices" blinded me.

 

[JFC Fuller]

Not VSTOL.

Lift jets were the initial solution for achieving STOL ability in what became MiG-23 and Su-24. The lift jet-equipped prototypes lacked swing wings. In a thorough redesign, lift jets were removed, swing wings introduced to achieve STOL ability.

The DH.127 was STOL only too, designed to the Royal Navy's requirement for an 80 knot landing speed. This was presumably harder to achieve with a delta wing than with the variable geometry wings of the Vickers Type 581. For the Royal Navy, OR.346 was a STOL type that would provide a common airframe for both air defence (specifically CAP) and strike roles, the equipment fit varying for each. It was intended to be the Royal Navy's carrier based combat aircraft for the 1970s. Had the P.1154 not been imposed upon them they would have pursued a Vickers variable geometry design, the DH.127 was looked at but variable geometry was seen as the way forward.