Ekranoplan

Background 

Sea birds like the Pelican & Albatross have been doing it for millennia, the 1930's Dornier Do-X flying boat did it because it was under-powered, most aircraft do it when they are about to touch down, but only the Soviets brought the phenomena to a practical application. What is it ??  Flying in ground effect.

Known in the west as a Wing-In-Ground Effect or WIG, vehicle, it is called by the Russians an 'Ekranoplan' - which means, literally, 'screen plane'.

The 'effect' is encountered when an aircraft flies a few feet above the ground - or water - where the air beneath the vehicle is compressed to form an air cushion. By riding on this cushion, a vehicle can travel further than it would at altitude, for a given amount of energy. The two seabirds mentioned at the start of this article can be observed skimming across the surface of the waves, riding on their own 'air cushions' with very little energy expenditure. The Germans discovered that the Do-X actually flew further when travelling at extremely low altitudes than it did when it flew higher.

Unlike a hovercraft, which generates its air cushion mechanically, a WIG relies on its forward speed to create the air cushion - once it is 'up and running'.

The main exponent of ekranoplans in Russia was Rostislav Alekseev and he helped create the Central Hydrofoil Design Bureau. Many types of Ekranoplan were designed and tested, ranging from small, single-seat testbeds, through the six-seat recreational Volga, right up to the best know - at least in the minds of the general public - the mighty KM, the so-called 'Caspian Sea Monster'.

To put things into perspective, this latter craft, of which only one was built, weighed 540 tonnes, had a length of 106m, a span of 40m, a maximum range of 1500km and could travel at a staggering speed of 430km/hr.

A-90 Orlyonok

The subject of this review, the A-90 Orlyonok (Eaglet) was designed as a naval assault craft and troop transport. It weighed 110 tonnes, had a top speed of 400km/hr, a payload of 15t and a range of 2000km.
Principal dimensions were :- length 58m, span 31.5m and height 16m.

Power was provided by two Kuznetsov NK-8-4K turbofans of 10.5 ton thrust mounted in the nose for lift-off and a single Kuznetsov NK-12MK 11000kW turboprop mounted high at the fin for cruise thrust.

The whole nose of the A-90 aft of the cockpit could be swung open sideways to allow vehicles to be driven up a built-in ramp onto the cargo deck. Other variants, such as a SAR and ASW were proposed, but only four A-90's were ever built before the collapse of the Soviet Union meant that funds for further development dried up. The current status of the remaining examples is not know, apart from the fact that they are rusting away at the Kaspiisk Naval Air Base. 

To see few pictures of the A-90 Orlyonok - go here 

For more detailed information on the A-90 and other Ekranoplans & WIG's, go to the excellent Internet WIG website at :- http://www.se-technology.com/wig/

The Revell Kit

Moulded in mid-grey plastic, Revell's 1:144 scale kit of the A-90 comprises just 38 parts with a single clear part for the cockpit (bridge ?) windows.
 

The surface detail is rather strange - the panel lines are engraved, which is acceptable - but the plastic surface has a sort of orange-peel effect and looks as though it is made from a carbon fibre weave in some places. I suspect that the moulds have not been polished properly - maybe Revell were in a hurry to produce the kit ??  There are also a couple of prominent sink marks on the fuselage spine that need to be filled.

Fuselage

Construction begins with the upper gun turret with which rotates and has provision for the 12.7mm twin machine guns to elevate. The large nose intakes for the turbofans comprise two halves with a 'mesh' grille at the rear. The joint between the two halves is rather prominent and needs to be filled and sanded smooth - not the easiest of jobs.

The jet exhausts comprise a blanking plate and a nozzle on reach side. The four-bladed contra-props on the NK-12MK engine are tackled next. I tidied up the roots of the propellers with a sharp knife and file and cut off the rear collar on the mounting shaft so that I could fit the assembled and painted propellers at a later stage. Revell's instructions show the prop being assembled at this stage and being trapped in place between the fuselage halves. This is fine if you want them to rotate - but they do get in the way during assembly and I preferred to have fixed props fitted when all the painting and decalling was complete.

The sub-assemblies of the engine intakes and exhausts have to be cemented in place and the upper turret held in its locating slot before the fuselage halves are cemented together. Also to be added is the representation of the mainwheel undercarriage - or is it beaching gear ?  The A-90 is equipped with a 10-wheel retractable undercarriage plus a twin wheel nosegear for driving up a ramp or beach to unload its cargo. The nosewheel on Revell's Eaglet is just represented by a depression with half-wheels for the nosegear and an insert with 8 half-wheels for the maingear  (there should be 10 according to my references). 
 
 

There is no provision to have the undercarriage extended - no can the A-90's nose be depicted in the open position to unload cargo. On the other hand, Revell do not provide any kind of stand on which to display the model - it just sits on its planing bottom neither in nor out of its operating element.

Meanwhile, back to the main undercarriage ……

Take care when fitting this component - part number 20.  It locates on a ridge moulded into the fuselage halves, but the location is a bit vague. Make sure that it sits as far forward as possible.

With the intakes and exhausts, gun turret, mainwheels and a blanking plate for the rear turboprop in place, the two fuselage halves can be cemented together. The fit of these components is commendably accurate. 

Final detailing on the fuselage consists of the addition of the two-part radome/satcom dish, the one-piece flight-deck windows and an intake lip for the front intakes. Again, this lip needs to be blended in with filler and sanded smooth, something that is not easily done given the contours of the intakes. An intake flap that acts as a blanking plate then has to be added. The location of this part is also a bit vague and must be done by trial and error. I have been unable to find any details of this intake area in all my Ekranoplan references. Some publications intimate that this flap allows the intakes to be closed off at high speed, but I have no further information. I chose also to leave off the window glazing until after painting. There is no cockpit interior - I doubt if Revell were able to obtain any information about the cockpit - so they have sensibly left it out.

Wings

 The short-span wings on the A-90 kit are made up from left and right upper and lower halves with the concave undersurfaces being well represented. The wingtip endplate 'floats' are constructed from two vertically split halves that attach to the wingtips and do not require any filler.  The fit of the wings to the fuselage, however, did require a smear of filler - particularly towards the rear of the root fairing.

Tailplanes 

The horizontal tailplanes  are in left and right upper & lower halves and are cemented to the top of the fin. Again, no filler was needed on my model. The final item to be added is a long probe that is mounted at the top of the fin at the fin/tailplane rear junction. This looks like a Magnetic Anomaly Detector (MAD boom, but I am not sure about its true purpose.

Painting

Revell's instruction sheet gives colour options for two Eaglets - both of them grey !  The first option is for side number 21 that sports a large diving Eaglet logo on either side of the front fuselage, Soviet red stars on the wings and a 'waving' Soviet Navy flag on the fin. This marking option is not well represented in photographs, so Revell have done well to find it ! The other option is for the well publicised number 26 - with a far less colourful scheme without any logos or stars - just the side numbers and a 'straight' St. Andrews flag on the fin.

The instruction sheet shows both machines as having an all-over grey colour scheme - with instructions to mix the grey from 3 of Revell's paint colours. There are no FS numbers quoted. This scheme may well be correct for side number 21, but number 26 certainly sports a more colourful scheme of grey uppers with dark blue or black lower wings and planing bottom. This colour extends onto the leading edge of the wings and all over the wingtip floats and is separated from the grey on the fuselage by a white cheatline at water level.

I chose this latter, more colourful, scheme, but combined it with the more comprehensive decal option for side number 21. I don’t know if this is correct, but I figured that if number 26 definitely had this scheme, then why not number 21 ??

As for the paints used, I decided to forego Revell’s instructions and simply sprayed the model using a range of acrylic car sprays available in the UK from a nationwide chain called Halfords. For the grey I chose Halfords Ford Polar Grey and for the undersides I used their Ford Midnight Blue. It may not pass inspection by the colour police, but I defy anyone to tell me that the colours are wrong !  The only relief from the drab grey is provided by the contra-props, which have a white spinner with black blades, the satcom dish - which is in a contrasting grey - and the nose intakes, which have a crudely painted red surround on the real thing.

There is no cockpit interior – not that it matters in this scale – so the cockpit glazing was added at this stage. The fit is quite tight, so with a little judicious trimming, the window was simply push fitted into place. Take care not to push it in off centre – it can be lost into the interior !!! 

Displaying the Beast 

 With no undercarriage and no display stand provided, I decided to depict my A-90 in flight, banking slightly to port, as pictured on the front of one of my references. I cut a rectangle of Perspex – about 20mm deep by 80mm long and super glued it to the planing bottom under the wings. I then cut an 80mm disc of Perspex and cemented this to the bottom of the rectangle so that the Ekranoplan sat level fore-and-aft but leaned to port with its wingtip float almost touching the ground when viewed from the front.

The model could now be displayed independently on any surface, but to make it more versatile I arranged a sea base into which I could place the model for display. This was made from a rectangle of thick plastic card, cut slightly larger than the overall dimensions of the model. Offset from the centre of this rectangle, I cut an 80mm hole – into which the base of the stand could be fitted. 

The plastic card was sprayed blue using car aerosol cans and when it was dry, I applied my ‘sea’. This was a sheet of blue cellophane, cut slightly larger than the plastic card so that it could be folded around the edges. The cellophane was then screwed up into a tight ball and when unravelled and spread out flat it was glued onto the blue-painted plastic card. This gave a very satisfying sea effect where the cellophane was wrinkled with pockets of air being trapped between the cellophane and card giving darker areas. It really is a quick and easy way to depict calm seas. The final touch was to spray a tight vee of white foam behind where the port wingtip float would be. The model can be inserted or removed from the base as required.


Note - I made the plaque before I knew that 'Orlyonok' translates to 'Eaglet' and NOT 'Sea Eagle' ! 

Conclusion

Revell’s kit of the A-90 Orlyonok is a very welcome release and the finished model certainly draws the crowds whenever I display it. Most members of the public think they recognise it and say ‘ah yes – I have seen the TV documentary about these things – that is one of those Caspian Sea Monsters !’

When I point to the little chart that I have showing that the A-90 is about half the size of the Caspian Sea Monster, they are really taken aback that something so large can travel so fast so close to the sea.

View showing the relative sizes of the 'Caspian Sea Monster' (KM) and the A-90.

I have only a couple of concerns about Revell’s kit and that has to do with the accuracy of the nose contours. I think that Revell have got the shape wrong. The top of the nose in the area of the intakes is too flat and has a shallow vee shape when viewed from the front. The real thing is more rounded. The intakes are also too big - which alters the whole shape of the nose. Finally, the cockpit is too flat sided and parallel. On the real A-90, the cockpit windows slope outwards from top to bottom when viewed from the front and the whole cockpit gets wider from front to rear and blends into the fuselage at the rear. Revell’s cockpit stands proud of the fuselage too much.
 

Still, it is a welcome addition to the model collection – and it is certainly an eye-catching subject. 
I hope that sales of this ground-breaking kit are sufficient to encourage Revell to tackle other Ekranoplan subjects - a KM 'Caspian Sea Monster' would be terrific, as would the even stranger Bartini VVA-14.


Note the lack of a prominent hinge line on the rudder - compare with pictures of the real thing !

Compare the model nose shape with the real thing !

Picture showing the sideways-hinged forward fuselage.

Ken Duffey

May 2000 

And now for something completely different ............................
 
 

The Revell A-90 painted up as a 'what if ?' in Virgin Atlantic colours - just for fun.
Gun turret is removed and props are replaced by 'turbofan' made from plastic tube. 
Decals are from Liveries Unlimited Boeing 747 set.