Mutley's Hangar

Introduction

The de Havilland 'Sea Vixen' from Skysim has been around for a while and is available for FSX and FS2004. It is one of only two products available from Skysim, both being released in 2008. Not only a unique aircraft from the halcyon days of post World War II British aircraft manufacturing, it is also an aircraft add-on type not commonly seen.

Background

The de Havilland DH.110 'Sea Vixen' is a twin boom, twin-engine, 1950s – 1960s, British, two-seat, jet fighter of the Fleet Air Arm designed by de Havilland at Hatfield, Hertfordshire.


The 'Sea Vixen' is the naval version of the DH.110, infamous for the appalling 1952 Farnborough air crash that killed 31 people and injured approximately 60 others.

Unlike its doomed land based version, the 'Sea Vixen' saw extensive service in the Royal Navy, with approximately 140 aircraft produced at Christchurch in Dorset. However, it did not attract any sales to foreign armed services. Two versions were produced, the FAW.1, entering service in 1959, and the FAW.2 which entered service in 1964. Some FAW.2s were converted to target Drones and re-designated D3.


The principal difference between the FAW.1 and the FAW.2 being a redesigned and enlarged tail boom which allowed further fuel tanks, an improved crew escape system, further electronic counter measures, and significant changes in armament. This change in armament allowed the FAW.2 to carry more sophisticated air to air missiles, and larger and updated air to ground rocket and missile systems. The cost of this upgrade was the loss of the FAW.1s 1,000 lb bomb carrying capability. In the photographs above and below, you can clearly see the most visible difference by looking at where the tail booms join the wings. It was towards the end of their service life that a few FAW.2 variants were converted for target drone use and redesignated as a D.3.


The aircraft saw action during the 1960s, supporting British carrier based operations in Africa, the Middle East and Malaysia. The last of the Fleet Air Arm aircraft were retired in 1974.

de Havilland DH.110 'Sea Vixen' FAW.2 Specifications:
    ●  Crew: two, pilot and observer;
    ●  Length: 55 ft 7 in (16.94 m);
    ●  Wingspan: 51 ft 0 in (15.54 m);
    ●  Height: 10 ft 9 in (3.28 m);
    ●  Wing Area: 648 ft² (60.2 m²);
    ●  Empty Weight: 27,950 lb (12,680 kg);
    ●  Loaded Weight: 41,575 lb (18,860 kg);
    ●  Maximum Take-off Weight: 46,750 lb (21,205 kg);
    ●  Power Plant: 2 Rolls-Royce Avon Mk.208 turbojets, 50 kN (11,000 lbf) each;
    ●  Maximum Speed: Mach 0.91 (690 mph, 1,110 kph) at sea level;
    ●  Range: 790 mi (1,270 km) with internal fuel;
    ●  Service Ceiling: 48,000 ft (14,600 m);
    ●  Rate of Climb: 9,000 ft/min (46 m/s);
    ●  Wing Loading: 64.2 lb/ft² (313 kg/m²);
    ●  Thrust/Weight Ratio: 0.54;
    ●  Hard Points: six and provisions to carry combinations of:
        ●  Rockets: 4 Matra rocket pods with 18 SNEB 68 mm rockets each;
        ●  Missiles: 4 Red Top or Firestreak air-to-air missiles; and
        ●  Bombs: 1 Red Beard freefall nuclear bomb.
    ● GEC AI.18 Air Interception radar.

Availability and Installation

The Skysim 'Sea Vixen' is available directly from the Skysim web site (www.skysim.co.uk) and comes in both download and boxed versions. The download costs £20.00 and the boxed £25.00 (at the time of writing). The version reviewed here is the FSX download version, but I have no reason to think it is any different to the boxed edition in terms of what you get. The FS9 version has not been reviewed, but the manual indicates no differences.

Once purchased, the buyer is given a link to download the aircraft with a fixed number of downloads. Beware, the link also has an expiry date, after which the product is no longer available, and a re-purchase is required. The active life of the download link is quite short so keep the download safe. This aspect, given the never ending download link life of other payware providers, is not good and is reflected in the score for this section. To be safe, I would have purchased the boxed version if I had realised this shortcoming from the start.

The download consists of an executable file of about 6MB in size. The installer is simple to use and you must enter the registration key which is provided by email. The actual HDD space required for the installation is unknown, but is appears to require approximately 180MB, so expect the installation to be in excess of this.

There has been very little activity in the way of updates since the aircraft's release and consequently, there is no updated installer for P3D. Not having P3D myself, I cannot say if a manual install is possible.

Support for the product is available via the forum on Skysim’s web site, but again, this seems to be largely inactive and has been for some time. Skysim sell this add-on direct from their website (www.skysim.co.uk), however, the secure access for payment details has a lapsed security certificate. So I leave you to take a view on payment security.

Documentation

Documentation is provided in an HTML document and covers all three versions of the aircraft. At a little over 1,400 words it is not extensive, but it is well illustrated. It provides an overview of the aircraft, a key to all the pilot's panels, with detailed views and instructions where applicable. The key concentrates on the virtual cockpit and only illustrates the difference between the widescreen and standard 2D cockpits. There is a brief section which covers starting procedures and another that covers the autopilot operation. These two sections are part of the virtual cockpit tour.


Represented aircraft versions are covered at the end of the manual, with a couple of screen shots of the FSX 'Select Aircraft' screen but no words. It gives the reader no feel for what to expect from the variations included in the package.


In my opinion, this is the bare minimum to be expected in a manual for a product such as this. On the plus side, it is brief and to the point, but covers no differences between the types of aircraft and no information on other aspects of the flight systems other than start up.

I would like to see a few checklists in the manual, although these are included as part of the 'Kneepad' pop-up, and more detail on the included variants. I would also like to see some more background information, such as details of the flight parameters of the two versions, and some information on how these aircraft were flown operationally. It is fine to have a well simulated aircraft, but some information on how to simulate its operation is often overlooked.

I understand some like to be able to spend five minutes reading the manual and then just get strapped in and into the air, but the manual barely satisfies even this approach. The manual is of the a level I would expect of a detailed freeware aircraft and it seems very much like an afterthought.

You can read the manual at:
www.skysim.co.uk/cvixhtml/cvix_readme.html

Model Features

Skysim claim every system, every actuator and every instrument, within the constraints of MSFS, has been modelled down to the very last detail, and the model retains a smooth performance on even modestly specified PCs. They also claim the flight model is endorsed by real world ex-Fleet Air Arm pilots. However, they do not state which version of MSFS provides the constraining limitations. As this is an offering for both FS9 and FSX, I can only assume the limiting constraints are associated with FS9.


Features and animations include:
    ●  wing fold,
    ●  canopy openings,
    ●  nose cone opening,
    ●  fuel probe extension,
    ●  selectable weapons and external tanks,
    ●  2D panel,
    ●  authentic sound set,
    ●  flying surfaces which realistically droop when hydraulic pressure has decreased,
    ●  a full set of covers and steps which appear when powered down and parked, and
    ●  multiple texture sets.

The package is supplied with multiple texture sets with a total of 22 aircraft versions provided in the package. However, in reality, there are only 11 discrete aircraft represented as there is a widescreen and standard screen version for each aircraft. The difference between the versions relates to the screen aspect ratio for the 2D cockpit.


There are five FAW.1 aircraft, four FAW.2 aircraft and two D.3 aircraft, including several front line carrier based operational aircraft from the 1960s and the high visibility target drone operated by the Royal Aircraft Establishment. Each model is a faithful reproduction of the real world counterpart and they are finely proportioned models of the aircraft.


The thumbnails used for aircraft selection were disappointing. The 11 (x2) versions share just two thumbnail images, a grey FAW.2, and a yellow and red FAW.2 for the target drones. Regardless of the aircraft being an FAW.1 or an FAW.2, the thumbnail is the same. This is just unprofessional and lazy. If you are going to create a complex payware model such as this, accurate, representative thumbnails should be provided.


External Model

The external model is good and with all the animations you would expect from an add-on in this price range. Control surfaces, flaps, and the large underbelly spoiler are all well animated, as is the undercarriage movements. When you power down after a flight, the control surfaces droop as you loose hydraulic pressure - a nice touch.

Internal spaces visible from the outside, such as the spoiler, undercarriage, and flap voids, are well detailed with accurate representations of the various ‘innards’ that you would expect to see on the real aircraft. The wings fold nicely and, again, the revealed wing details are good. The wing fold is initiated by a cockpit switch, as is another nice touch, the opening of the nose cone to reveal the directional radar. Below are photographs of an FAW.2 with the nose cone open and an FAW.1 with the wings folded along with comparative images of the respective Skysim model features.

FAW.1 Nose Open

FAW.1 Wings Folded

'Exit 1' is the main canopy, which slides back. It also opens the ‘coal hole’ hatch which provides access to the navigator’s space. This glides nicely up when activated. 'Exits 2, 3, and 4' seem to have no function but make a noise when activated. It is a shame these functions are not used, even if to just separate the pilots and navigators canopy opening. There are a number of switches in the cockpit which allow change the external configuration of the aircraft. One adds a pair of wing fuel tanks, another loads missiles and a third adds a refuelling probe.

On powering down the engines and applying the parking break, the covers appear on the pitot tubes, engine intakes, etc. and red crew ladders appear. The only disappointment is the textures themselves. These seem drab and somewhat lifeless, and on a closer look are just bitmaps. There are no DDS textures with their associated alpha channels to provide the shine to metal surfaces that you expect with a more recent add-on. This aspect of the external model is one which could be improved on. Considering this model was release in 2008, reflective textures may have been considered to create too much of a performance hit at the time. However, all in all, the external model is good in regards to detail.

Internal Model

There are two virtual cockpit views with this model, the pilot and the navigator. The pilot’s cockpit does not disappoint. It seems a little less cluttered than the real world cockpit but most of what is in the real world cockpit is in this model. The textures are good and the comment I made about the DDS textures doesn’t apply here as the cockpits are matt in the real aircraft and look just right in the Skysim model. The functional switches are all animated as are important buttons and sliding controls such as the throttles. The aircraft can easily be started, flown and shutdown from the virtual cockpit.

'Sea Vixen' Cockpit

'Sea Vixen' Coal Hole

The only disappointment is the navigator's cockpit. This is only available as a virtual cockpit and is very sparse with only three dummy gauges in it. There is no radar steering joystick or twin radar scopes and associated switch panel, a shame, given the external access to the radar disk. I know this is not an important seat for flying the aircraft in FSX, but given the attention to detail with the external model, it is a pity to see this aspect scrimped on.

2D Cockpit and Pull-Out Instruments. The 2D cockpit is nicely produced and gives you access to most of the gauges but few of the switches, as these are in a panel on the right hand side of the cockpit. There are some pull-out instruments, and the image of the cockpit below shows where they emanate from. Personally, I tend not to use the 2D cockpit as I find the 3D cockpit provides a more immersive flight experience.


There are a total of five pull-out instrument panels:
    ●  Garmin GNS 500 GPS, not realistic for this aircraft;
    ●  throttle, not a great reproduction of the 3D cockpit version;
    ●  radios, a rendition of the standard FSX available functions and not like the 3D cockpit version;
    ●  switch panel, containing a subset of the 3D switch panel morphed into a useful but inaccurate square; and
    ●  warning lights, rendered to closely match the 3D version.

All pull-outs are fully functional and are clearly designed as handy tools and not accurate working models. As such, they are functional but disappointing.


Sounds

There is a full set of sounds included in the package which sound convincing enough during all stages of operation from start up to shut down. Not having heard a 'Sea Vixen' for over 30 years, I cannot comment on their authenticity. However, the sounds are well implemented with convincing start and shutdown sounds and all the appropriate changes in volume and tone that you would expect inside and outside the pilot's office, as well as in varying aspects around the outside of the aircraft. Animations are accompanied with convincing "whirrs and clunks" and add to the atmosphere of the flying experience.

Flight Characteristics

After the tragic loss of the DH.110 at Farnborough in 1952, the design of the wing structure was completely changed for the FAW.1. The resulting aircraft was very strong and was rated as outstanding in terms of its flight behaviour. Likewise, the Skysim model has few vices, and is a pleasure to fly, with take-offs and landings relatively easy to perform.

For this review, and as I was test piloting this military aircraft, I flew out of Farnborough, where much cutting edge aircraft testing was done in the 1960s. No specific flight plan was drawn up, and I used the south of England as my playground to see what this aircraft could do and when pushed to its limits. Having established a take-off speed of 140 kts and a clean stall speed of 100 kts, I lowered the landing gear, deployed full flaps, and found the stall speed had dropped to 80 kts. Useful information for landing.

For the remainder of the flight, I compared the Skysim model’s performance to actual performance specifications. My findings are detailed below.


FAW.1. The 'Sea Vixen' FAW.1 was slower than the FAW.2, being capable of 586 mph at sea level, has a climb rate of 14,000 ft/min. I have been unable to find a top speed for 40,000 ft but would expect it to be very similar to, but slightly less than, that of the FAW.2 at 610 mph. Its operational ceiling was 50,000 ft. The Skysim FAW.1 produced an exact 586 mph at sea level, the rate of climb was 13,000 ft/min, with a ceiling of 50,000 ft. Handling at low levels was crisp, and the aircraft only became slightly unstable after about 46,000 ft. So, the model gave a good representation of the aircrafts flight envelope.


FAW.2. The 'Sea Vixen', FAW.2 was capable of 650 mph at sea level, has a climb rate of 18,000 ft/min, and a top speed of 610 mph at 40,000 ft. Its operational ceiling was 48,000 ft. Skysim's model almost matched three of these statistics, achieving a speed of 650 mph at sea level, an overall climb rate of approximately 18,000 ft/min, and I was able to get the aircraft up to 50,000 feet as an absolute maximum. Handling at low levels was all you would wish for, and, again, the aircraft only became slightly unstable after about 46,000 ft. So, the model gave another good representation of the aircrafts flight envelope.

D3. This aircraft is a converted FAW.2 and has the same characteristics.

Clearly, the Skysim flight models, while broadly similar, are different for the two versions of the aircraft, and a good representation of them both. Skysim have made a creditable effort of the flight envelope.


Flight Dynamics

The look and feel of an aircraft is a very subjective topic. This aircraft flies beautifully and behaves just as I would want a jet of this pedigree to. Personally, I do not think there is much wrong with the flight model as was displayed in the tests described earlier. There are some nice touches with the model, such as the spool up time of the engines being slower than a modern jet.

Wanting some fun, I thought I would see what happened in a sustained vertical power climb when the aircraft’s power met, and was surpassed by that of gravity. The result was alarming, but not hard to deal with. My speed dropped in the climb and rapidly approached zero. Suddenly, the nose twisted sideways and was pointing directly at the earth. Only then did the stall alarm sound. Fortunately, the aircraft was kind, no tendency to spin was encountered and recovery was easy. It is just as well that the age of the airframe is not a factor in FSX!

Rolling, looping and other aerobatics are fun in this aircraft, but watch your speed as it is all too easy to red or blackout! My last bit of fun before I landed was some knap of the earth flying in Snowdonia. Flying low and fast through the mountain valleys is great fun in this aircraft, as long as you remember you have no reheat. Where a Tornado can pile on the power instantly, and add in reheat as well, to get you over that looming mountainside, this old bird needs just a little more forethought. It just makes it a bit harder.


Technical Requirements

The Skysim 'Sea Vixen' is for FSX / FS9 only. Other specified technical requirements are as follows:
    ●  Windows Vista or Windows 7 (32 or 64bit);
    ●  Microsoft Flight Simulator FSX with SP1 and SP2 (or Acceleration Pack) or Lockheed Martin Prepar3d Flight Simulator installed; and
    ●  Pentium V, 2.2GHz or similar, 1GB RAM, 512MB graphics card.

Performance

The Skysim 'Sea Vixen' had no discernable impact on frame rates, but with an older product on a system that is much faster than available at the time of its release, it would be surprising it there was any significant impact.

Value for Money

When considering the value of this product, I asked myself two questions, "Is it good value for money now?" and "Was it good value for money in 2008 when it was first released?". As I mentioned above, the download costs £20.00 and the boxed £25.00 at the time of writing. I think £5.00 is a bit expensive for a box and a CD, especially as the cost difference for Skysim's only other offering is only £2.50. However, the £5.00 is probably worth spending to avoid the short life download availability.

In 2008, I would probably be very happy with the value I received, perhaps with the exception of the manual which is a bit thin. However, by today’s standards, I expect something a little more polished. Ok, it is a low priced product, but there are some freeware products out there which offer better documentation and better textures.

Having said that, I liked the aircraft, and ignoring its shortcomings, I really like flying this add on. If Skysim updated the product to put the gloss on it, and paid a bit more attention to some details, they would have a real winner, despite its 2008 publish date.

Conclusion

The Skysim 'Sea Vixen' is a good aircraft add-on. Skysim have made a credible attempt at recreating this aircraft for FSX. The flight characteristics of the aircraft are modelled reasonably well and the exterior and interior visual models are also good. Detected issues detracted from the model overall but do not impact or significantly detract from the general flying of the aircraft. A great military aircraft, the Skysim 'Sea Vixen' is great to fly.

Verdict and Rating

A reasonable product from Skysim, the 'Sea Vixen' displays a good level of accuracy, quality and attention to detail. Some aspects where disappointing and detracted from the model overall.

Pros:
     ● Good representation of the flight dynamics.
     ● Good sound set.
     ● Reasonably priced for the download.
     ● Fun to fly.

Cons:
     ● Dull exterior textures.
     ● Poor documentation.
     ● Download link expires very quickly.

Verdict:
● External Model:	7.0/10
● Internal Model:	7.0/10
● Sounds :	9.0/10
● Flight Characteristics (does it fly by the numbers) :	9.0/10
● Flight Dynamics (does it feel like what it looks like) :	9.0/10
● Documentation :	5.0/10
● Value for Money :	6.0/10

Skysim 'Sea Vixen' is awarded a Mutley’s Hangar score of 7.4/10, with a "Recommended" and a Mutley's Hangar Bronze Award.