SM-2P7 taking off from water
From the introduction you may conclude that WIG boats are a new invention, the opposite is true. The phenomenon of ground effect has already been known since the early days of aviation and just before the second world war some experimental WIG craft were built in Scandinavia.
It was not until the nineteen-sixties however, that the first serious WIG boats were developed. The contributions of two individuals were very significant: the Russian Rostislav Alexeiev and the German Alexander Lippisch. They independently worked on WIG technology with entirely different backgrounds, encountered the same problems and came to very different solutions. Alexeiev had a background as a ship designer and was obsessed by speed. He thought of a WIG boat as a hydrofoil boat with its wings just above the surface, rather than submerged. Whereas Lippisch, an aeronautical engineer, was intrigued by the potential to increase the efficiency of aircraft by flying close to the surface. The influence of Alexeiev and Lippisch is still noticeable in most of the WIG boats developed since then.
In the USSR the WIG developments took place at the Central Hydrofoil Design Bureau (CHDB), lead by Alexeiev. As the name already suggests this bureau was engaged in hydrofoil ship design. The will to create even faster transportation over water lead Alexeiev to the development of ekranoplans. The military potential for such a craft was soon recognised and Alexeiev received personal support from Kruchev including virtually unlimited financial resources. This very important development in WIG history lead to the Caspian Sea Monster, a 550 ton military ekranoplan, only a few years after this top secret project was initiated.
Initially Alexeiev designed WIG boats with two wings, set up as a tandem. This was an obvious choice for him at that time, because of his hydrofoil boat background. The first full scale WIG boat of the Design Bureau was the tandem craft SM-1, but the tandem concept was soon rejected in favour of the ekranoplan design. The reason for this was the very high take-off speed of the SM-1 and its very rough ride quality and poor maneouvrability. The first ekranoplan as we know it now, the SM-2P, was built in 1962 with a low aspect ratio wing and a large, high T-tail. Another feature found in most later ekranoplans were the jets that were blowing under the wing to assist at take-off. The purpose of this so-called PAR system was to decrease speed and loads at take-off and made the craft amphibious as well.
SM-2P7 taking off from water
KM in high-speed cruise
Two Orlyonoks on a platform
The 550 ton KM (Russian abbreviation for prototype ship) was baptised in 1966. In the five years before that, a number of manned and unmanned prototypes were built, ranging up to 8 ton displacement. They were designated SM followed by a number, where SM is the Russian abbreviation for self-propelled model. The KM was built in the (at that time) closed city Gorky, now called Nizhny Novgorod. No foreigners were allowed there and only when the KM was transported to the Caspian Sea for trials it was discovered by Western intelligence on sattelite photos. At first they did not know what it was and assumed that it was a seaplane under construction, later they found out what it was and called it the Caspian Sea Monster. This name is sometimes also used for ekranoplans in general. To illustrate the secrecy surrounding this project at that time: it was even forbidden to use the word ekranoplan in public.
US spy-sattelite photo of KM
When the KM programme was launched in 1963 it was very ambitious, it was to be more than 100 times heavier than the SM-2P, which was the heaviest ekranoplan at that time. Basically the KM was far ahead of its time and even today many developers of WIG boats do not consider a craft of this size feasible within the next few decades.
After the experimental craft the Russian ekranoplan program continued and lead to the most successfull ekranoplan so far, the 125 ton A.90.125 Orlyonok. The Orlyonok incorporated many features that had been tested separately in earlier designs: it was amphibious, it had a huge turboprop engine for cruise thrust at the top of the fin and two turbofans in the nose for air injection. A few Orlyonoks have been in service with the Russian Navy from 1979 to 1992.
The most recent large ekranoplan from the former Soviet Union is the 400 ton Lun which was built in 1987 as a missile launcher. It carried six missiles on top of the hull. At the time when the Soviet Union fell apart there was a second Lun under construction. It was about 90 percent finished when the military funding stopped, because of the financial situation and the end of the cold war. Some ideas were raised for a new life for the Lun, they ranged from a passenger ekranoplan to a rescue vessel. The second Lun was eventually renamed to Spasatel, the military systems were removed and work started to finish the craft as a rescue vessel. Unfortunately there were financial problems and the work had stopped completely by the mid-nineties. Every now and then plans are presented to finish work on Spasatel, but it will probably never be finished due to lack of funding.
After the collapse of the Soviet Union, developing or maintaining big ekranoplans became impossible for the Russians and the design bureaus started focusing on smaller ekranoplans for non-military use. The CHDB had already developed the 8 seat Volga-2 in 1985, but other design bureaus and companies emerged that wanted to exploit the Russian lead in WIG technology. The most successfull of these is Technologies and Transport where the Amphistar was developed as a smaller and more modern derivative of the Volga-2, both are now in production.
Two Amphistars on a platform
Series production of Volga-2
The story of Alexeievs western counterpart, Lippisch, also started around 1960. At that time he was asked to build a very fast boat for Mr. Collins from Collins Radio Company in the USA. Alexander Lippisch was already a well known aircraft designer at that time, being called the father of the delta wing. In the second world war Lippisch designed the Me163 rocket powered delta wing airplane which was well ahead of its time. The boat for Collins, the X-112, was at least as revolutionary a design with its reversed delta wing and T-tail. This design proved to be stable and efficient in ground effect and although it was succesfully tested and followed up by the X-113, Collins decided to stop the project and sold the patents to a German company called Rhein Flugzeugbau (RFB) which further developed the reversed delta WIG boat.
X-112 in very low ground effect cruise
X-114 in a low banked turn
Airfisch 3 in cruise
FS-8 in cruise
In Germany the military potential for WIG boats was recognised and RFB was contracted by the German military to develop the X-114, requiring it to fly without ground effect as well as in ground effect. It became apparent that the conflicting requirements of a WIG boat and an aircraft lead to a compromise with little advantages and that the true power of WIG technology lies in staying close to the surface. Therefore the development was continued with the Airfisch family of WIG boats that were incapable of sustained flight without groundeffect. Meanwhile Hanno Fischer had taken over the project from RFB and he pursued Lippisch' work at his own company called Fischer Flugmechanik. Their two seat Airfisch 3 was a very successfull design, which has recently been scaled up to seat 6 passengers. This craft, the FS-8 will soon be series produced by a Singapore-Australian joint venture called Flightship.
While the Airfisch technology was being made ready for the market, Fischer was already working on the next generation of WIG boat with hovercraft technology to assist at take-off. The 2 seat hoverwing prototype HW-2VT has been successfully demonstrated many times and now development continues with a 20 seat version.
Joerg IV in cruise
Joerg IV in cruise
HW-2VT in cruise
Although Alexeiev discarded the tandem wing principle after having tested the SM-1, the concept was later rediscovered by the German Günter Jörg. After many radio controlled models he succeeded in developing a stable WIG boat with two wings in a tandem arrangement, the first manned craft was the Jörg-II. The tandem WIG boat excels in simplicity and low cost and is the most boat-like of all WIG concepts. These facts may explain their initial success with boats up to 25 metres in length built. Unfortunately some technical and business related problems stood in the way of true commercial success.
The above are the most relevant developments in WIG history, but there have been many smaller projects around the world, some of which should be mentioned here. The Kawasaki KAG-3 was a WIG boat with water propulsion, but the project was abandoned due to stability problems. In the USA there have not been many projects that went beyond the drawing board. Especially Lockheed and David W. Taylor Naval Ship Research and Development Center (DTNSRDC) have conducted a lot of research work. DTNSRDC especially in the area of PAR. Some years ago a company called Flarecraft copied the Airfisch-3 and scaled it up. Due to their lack of expertise the Flarecraft L-325 was a technical failure, although the attention from the market and the media was overwhelming.
TY-1 cruising past at 150 km/h
L-325 in cruise
Perhaps the most significant developments at this moment, aside from the Hoverwing, are taking place in China and Australia. Australia not only with the FS-8, but the well established catamaran builder Incat is developing a very large trimaran ferry with WIG support. Although this may not be a true WIG boat, since it always maintains water contact, it could be a first step to widespread market acceptance.
Chinese companies have been very actively developing WIG boats over the past decade. At least three different groups are working on their own WIG boat. Two of them focus on Russian technology with the TY-1 and Swan that technically resemble the Volga-2. The third group has taken the Lippisch approach and added PAR to it, resulting in the XTW-4.
