
“Interestingly. I was looking at real Stealth Helicopter projects from early 1982 in my role as Westland Helicopters Head of Future Projects. I remember showing an image of WG44 at a defence conference, which took place shortly after the sinking of ‘Atlantic Conveyor’.
Another related subject in which I have experience is the NOTARâ„¢ (no tail rotor) system developed by Hughes / McDonnell Douglas Helicopters (MDH) and used on the MD Explorer. It depends (in part) on a boundary layer control system called Circulation Control, where a jet of air is ejected out of a slot (or slots) running along a curved surface. Changes in the mass flow from the slot allow rapid changes in the lift (circulation) around the aerofoil. Very high lift coefficients (>6.0) can be obtained and rapid variations can be achieved for control purposes.
My PhD related to experimental tests and a theoretical model of such a system, the latter being capable of modelling more than one blowing slot on a surface.
Andy Logan of MDH, who gave a paper on NOTAR to the Royal Aeronautical Society (RAeS) when I was the Chairman of the RAeS Rotorcraft Committee was kind enough to reference my PhD in his presentation. (A developed version of my theoretical model was used for quick look optimisation of NOTAR, as it could handle multiple blowing slots).
Having said all this, what about the Testors Stingbat LHX?
A quick look at the photographs of the model reveals some interesting features, but leaves a number of questions unanswered.
The main features include:
- A heavily faceted airframe with (presumably retractable) skid undercarriage, although it is not clear where the latter is stowed, or why the skids appear to be in two pieces.
- A retractable sensor of some sort below the nose
- A three-barrel gun turret mounted centrally under the fuselage
- Retractable weapons stowage for a small number of quite small missiles (possibly only one each side). These have the appearance of air to air rather than anti-armour weapons (such as Hellfire or Brimstone)
- A small louvred nozzle at the tail, presumably for anti-torque and directional control
- It is not clear how the engine intake and exhaust system are supposed to work and how infra-red shielding and suppression are managed. (I am giving the designer credit for not imagining that the exhaust is ducted out of the tail nozzle).
- A three bladed rotor which is swept in a crescent shape from root to tip. The blades appear to have a separately controllable outboard section.
- There is no sign of treatment to minimise the radar signature of the cockpit apertures.
As one might expect, there are a few issues with this design. My main comments relate to the tail boom and anti-torque / directional control; Infra-red suppression; viability of the gun turret solution shown; inadequate downward view from the cockpit; design of the main rotor blades; weapon load out; undercarriage.
Tail Boom & Directional control
A really quite significant thrust is required to counter main rotor torque and provide for yaw manoeuvre against the torque when in and around the hover. In the MD Explorer, the downwash across the tail boom is deflected by the circulation control air ejected from longitudinal blowing slots. This produces a side force on the tail cone that partially offsets the main rotor torque (this requires a circular section tail boom and is not consistent with the shaped rear fuselage shown. An adjustable tail nozzle (with air supplied by a gearbox-driven fan) supplements the blown tail boom. In forward flight, when the downwash no longer blows across the tail boom, directional stability is provided by twin fins (with rudder control) mounted on the end of a tailplane.


The Boeing- Sikorsky RAH-66 Comanche used a version of the Fenestron (fan-in-fin) anti-torque control, dubbed Fantail by Boeing Sikorsky) allied to a canted tailfin. The Fantail was optimised for reduced acoustic signature (compare, for example the penetrating pure tone of the Gazelle with the much quieter systems on the EC135 and later model of the Dauphin).
With no fin area and a very small exhaust nozzle, there must be serious doubts as to the directional stability and control of the Stingbat LHX design. Furthermore, the rear fuselage shaping is inconsistent with the implementation of a NOTAR system, if that was considered.
Infra-red suppression
The shaped tailcone of the Comanche was mainly taken up with a bulky exhaust infra-red suppression system and this was also a prominent feature of the Westland WG45 and WG47 projects. I’ll assume that the Stingbat adopts a system similar to that on the Comanche.
Gun turret
Helicopters adopt a nose down attitude in forward flight. This means that frontal ground targets appear above the nose of the helicopter when it is flying at speed. Firing the gun at such a target means firing upward relative to the helicopter, universally resulting in a forward-mounted turret with decent upward look angles. (see A129, Tiger, Cobra, Hind, Rooivalk, Apache, Havoc, etc). That shown on the Stingbat is entirely impractical.
Cockpit downward view
The flat shaped nose and wide fuselage may obstruct downward view, although this could be overcome by slaving the retractable sensor to a helmet-mounted sight. A sensor behind a mesh-covered aperture (as adopted by the F-117) might offer a lower signature solution that the retractable sensor pack shown. (Although the F-117 does find it worthwhile to implement retractable comms aerials).
Main rotor blade design
The curved blades look wrong. The primary means for reducing helicopter acoustic signature are having a modest main rotor tip speed (think Sea King and AW101), avoiding high tail rotor noise, and avoiding flight paths that result in blade slap.
Assuming a low basic tip speed, high Mach numbers will only be encountered close to the advancing blade tip. This explains why those helicopters that do feature any blade sweep only do so close to the tip. The other major difficulty is that sweep along the whole blade will introduce large in-plane bending loads in the blade due to the centrifugal loads trying to straighten the blade out. (The end result would almost certainly be increased rotor system weight).
The two-section blade looks as if it has a separately controlled outer section with a small control tab. This is a good idea as it would potentially allow higher frequency control inputs (known as Higher Harmonic Control), which could reduce external noise, possibly eliminate blade slap, and reduce on-board vibration.Â
Weapon load-out
The primary targets for most attack helicopters are enemy main armour, command and control vehicles, and air defence systems. Some form of tandem warhead precision guided missile is required – these are quite large and heavy. The ones shown fitted to the model look like reduced length AIM-9s or, at any rate, air-to-air rather than anti-armour weapons.
Because each sortie carries with it a finite probability of being engaged by the enemy, it is important to carry enough weapons on each helicopter that a small group of helicopters can inflict significant damage without having to fly multiple sorties. This typically means eight weapons (assumed for WG-44 to WG47), with Apache carrying a maximum of sixteen weapons. Even the Comanche managed six weapons in its weapons bay.—Â
The provision on the Stingbat does not appear to be sufficient.
Undercarriage
It’s hard to tell exactly what is provided, but Crashworthiness (used to be based on Mil Std 1290A) is a key consideration. I assume that the skid undercarriage is retractable for signature reasons, but I cannot tell how it is stowed. It looks too flimsy to be crashworthy and the apparent introduction of shock struts may prove problematical in terms of the avoidance of ground resonance.”
Ron Smith, Co-author of Two up down under Â
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Tomorrow Russia faces Saudi Arabia in what the Financial times has dubbed the worst World Cup opener ever, leaving confused fans to drift off into their belligerent fantasies. With this in mind, who would win in an aerial war? Over to our Football & Air Defence Specialist Calista Wildenrath with a rather tasteless war/sport crossover.Â
“Both Russia F.C. and the R.S.A.F Rovers have reputations for high risk tactics, excepting relatively high losses. Russia F.C. remains surprisingly uninterested in precision playing, using overwhelming force and loose management approach to achieve its results. Traditionally RSAF (which is a lavishly equipped side) has been considered a team of rich careless playboys – but some would say those days are over. RSAF has still endured many hard losses against local upstarts Yemen United. Let’s see how the two sides stack up.
Goalkeepers (SAMs)
Saudi Arabia PAC-2 ‘Pac man’
Regarded as one of the most reliable shot-stoppers among Western long-range SAMs.
Its predecessor in this position, the original Patriot, was highly rated in the 1991 Gulf World Cup, but subsequent video replays showed that it failed to stop most of the long-range efforts launched by the Iraqi strikers.
Following its transfer to Saudi Arabia, the Patriot more recently endured a torrid season against Houthi opposition.
Russia S-400 ‘Triumph Acclaim’Â
It is hard to believe that this big-shouldered American is 39 years old, but that does not stop the F-15C from making sure that his performance levels reach RSAF Rovers’ required standard. Though old, he remains the most successful defender (in term of loss-kill rate) of his generation.
Russian Air Force F.C. Mikoyan MiG-31 ‘Foxhounds of love’
The Russian stalwart has once again had a stellar season. He is as reliable as ever in the pitch and always keeps a calm and composed head when faced with high-pressure situations. The MiG-31Â is an old-school defender in the sense that he values speed over the art of tackling. There are few players who can beat him aerially, while only few can beat him for speed when he is on form.
Russia FC’s talismanic Blackjack is a favourite of the manager. Far bigger and more powerful than anything possessed by the fun-loving RSAF, it’s a throwback to the 1970s style of brute force and massive long distance shooting. Though impressive, this old-style centre-forward is somewhat inflexible.
Saudi: Panavia Tornado IDS ‘Tonka Stonker’
Confounding the experts who expected RSAF to place the Strike Eagle or Typhoon in striker role, they’ve opted for the perennial IDS. While some observers argue that the ageing Tornado should have been retired from the first team some time ago, it’s continued to play a vital role in the Saudi strike force and the punchy centre-forward still has some clever tricks up its sleeve. Compared to Russia’s titanic Blackjack the Tornado is tiny with short endurance. Interestingly, both teams are putting up a swing-wing for the striker role.
Russia FC’s eccentric captain Beriev A-50 is a mainstay of the team with over thirty years service. Known for his short endurance and primitive approach he is a controversial figure lacking the sophistication of RSAF’s new Swedish coach.
Saab 2000 Erieye ‘Erieye for the straight guy’Â





Jim Smith had significant technical roles in the development of the UK’s leading military aviation programmes, from ASRAAM and Nimrod, to the JSF andÂ
As well as some of the F-117 features, Testors has done quite a good job of giving the aircraft a Russian look. Partly, the use of a MiG-23- like undercarriage, and partly subtle stylistic and colour scheme aspects which just convey a less-Western look. Paradoxically, the crude-looking faceted shaping turned out to be more accurate than the smooth surfaces of their F-19 concept.
From a propulsion perspective, the intakes perhaps look a little more likely to work than those of the F-19, and still bear no resemblance to those of the F-117. From a stealth perspective, however, the whole aircraft is full of changes in angle which look counter productive to maintaining a low signature. In particular, the under-surface of the aircraft does not feature the flat surface of the F-117, and appears unlikely to be successful in managing the
Aerodynamically, the





























While the aircraft will not have the stealth and super-cruising abilities of the F-22, the super-manoeuvrability of the Su-35 or impressive weapons-carrying performance of the Rafale, the Gripen E will be an extremely potent aircraft punching well above its weight. Weight and cost often correlate for military aircraft and it is interesting to note that the F-35, intended as the ‘low’ (weight/capability) to the F-22’s ‘high’, has an empty weight of 13154 kg, compared to the Gripen E’s svelte 8000 kg (the respective maximum take-off weights are 27000 kg and 16500 kg). Though the F-35 may, by a combination of manipulation and mass production, eventually have a competitive quoted price tag, the Gripen E will be far cheaper to operate and maintain. The Gripen has a history of punching above its weight class, with the C/D frequently entered in procurement competitions against the middle-weight Typhoon, Gripen and late-life F-16. Indeed when Hush-Kit asked Jim Smith , who had significant technical roles in the development of the the JSF andÂ

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