GSAL Eindecker

Can you imagine the excitement of diving towards the enemy in an open-cockpit monoplane, the cowling-mounted Spandau machine gun ready to unleash a deadly blast towards flimsy Allied biplanes drifting unawares below?

Words and images: Geoff Jones

Can you imagine the excitement of diving towards the enemy in  an open-cockpit monoplane, the cowling-mounted Spandau machine gun ready to unleash a deadly blast towards flimsy Allied biplanes drifting unawares below? If such WWI fantasy and small aeroplanes are your thing, then you may want to head for rural Gloucestershire and Grass Strip Aviation Ltd (GSAL), which is selling the embodiment of these dreams in the form of a three-quarter scale version of the Fokker E.III Eindecker - the deadly fighter made infamous in the ‘Fokker scourge’ of 1915.

Not only is GSAL’s aeroplane a really convincing looker, it is in the least restrictive classification of UK aviation - the sub-115kg empty-weight category - and it is extremely cheap to buy and then fly. To use the modern vernacular, it ticks all the boxes. Currently just one other UK design, Terry Francis’s Reality Kid, is available in this category. (The Kid has the benefit of being recognised as a BCAR Section ‘S’ microlight, which means that it can be sold, built and flown in other European countries - but establishing this was a lengthy and expensive process.)

The GSAL Fokker E.III Eindecker kit has its origins in the Airdrome Aeroplanes [sic] Eindecker - one of 22 different WWI-style plans-built and kit aircraft designs that the US company, operated by Robert Baslee, has produced since the 1990s. Over 200 of these ‘rag-and-tube’ machines have been sold to date. While Airdrome Aeroplanes’ designs share a similar riveted aluminium structure, their weights vary considerably. The Eindecker is one of the few that is FAR Part-103 legal.

GSAL has made innumerable modifications and improvements to the design. The company says a 12- to 15-month build time is average: if you don’t want to build it yourself, it is legal for GSAL to build it for you.

Based at the former RAF Aston Down airfield near Stroud, Gloucestershire, the company has three directors: former Concorde flight-test engineer Robin Morton; automotive project designer George Simoni; and restaurateur Shaun Davis. All have been passionate microlight pilots and aircraft builders for many years and all are members of the same flying club at Kemble. Over a boozy meal one evening, it became clear that the three of them had a favourite WWI aircraft in common - the Fokker Eindecker. There and then, they agreed to research available Eindecker kits and to each build one. In the cold light of day, and having approached Robert Baslee and Airdrome Aeroplanes, they were told that if they bought four kits then they could become agents for the US company. This was 2007 and the die was cast - GSAL was founded and then the hard work really began.

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It was not until 24 August 2011 that GSAL’s prototype first flew, and by the time of my visit to GSAL in January this year, flight testing was nearing completion. The company has already sold seven Eindecker kits.

Different and upgraded

The Eindecker kit that GSAL now supplies is considerably different to and upgraded from the US equivalent, and this speeds up the building process.

“If you can build a model aeroplane you can build our Eindecker kit,” Robin Morton told me. “We want to give our customers the least amount of work reasonably possible, within price budgets. We pre-bend all aluminium tubes, the vertical tail and horizontal stabilizer outlines and the wing ribs and control surface ribs as well. Main fuselage construction is riveted tube and gusset. AA just supplies flat sheets of aluminium, but we take these and bend the edges to shape. Similarly, there is 500ft of straight tube in the US kit, so we bend this wherever necessary.”

GSAL prides itself on its product and its customer support, and if there is any aspect of the build that is causing builder difficulty it will offer immediate assistance. GSAL claims to have improved the integrity of the design, and has also produced its own full-size CAD drawings for everything except the wings, so that the Eindecker’s fuselage and tail can be built on a large table - just like the balsa-wood flying models of old. The company has also updated, numbered and catalogued the US drawings, and provided much more detail and information on the building methods and processes.

GSAL has written a comprehensive build manual, and it supplies AA’s build DVD plus a DVD of its own still photographs; showing every part of the build process. The company has a great website and a builders’/owners’ blog, as well as Facebook pages. The main structural modification introduced by GSAL  is the supply and fitting of 16 wing-bracing wires, eight of which stretch out to the upper wing from the cabane in front of the cockpit, and the other eight to the lower wing from the undercarriage - the US version has only eight. The full-span ailerons have been reduced to two thirds of their length because GSAL found that the ‘dirty’ air from the propeller wash caused buffet as it passed over the inboard part of the aileron - as a result, the handling has been improved, and drag and static break-out force reduced. (Original 1915 Eindeckers had no ailerons, but used wing warping.)

GSAL has modified the undercarriage to include a compression spring option in place of the bungee cord system, and a customer who is a professional engraver also supplies the brass data plates to attach to the cowling, and other parts of the aircraft - giving an extra touch of authenticity. The company continues in its programme of weight reduction without compromising structural integrity.

To assist with ground handling, particularly on hard runways, GSAL plans to fit disc brakes from a quad bike, operated from a lever in the cockpit. A folding wing version is also a possibility but most customers have so far opted for the simple de-rigging modification, taking two people about 20 minutes and leaving the vertical fin and horizontal tail in place.

The engine is the heart of the Eindecker, combined with propeller choice. GSAL has devoted much attention to this - engine options being Rotax 447, Briggs & Stratton Solo 35/40, Hirth F.28, Fuji Robin, the Canadian single cylinder MZ-34 (28hp). But the company’s preference - and the engine with which all its test flying has been conducted - is the Canadian CRE MZ-201, a 45hp in-line, twin-cylinder, two-stroke with electric and recoil start, dual ignition, belt reduction drive, carburettor and modified exhaust. This unit is extremely popular in the Americas, New Zealand and Australia but little used (so far) in Europe. The main drawback with a two-stroke is the dark art of mixing oil with fuel, but this kind of thing is bread and butter for many microlighters.

In the air...

As the flight test programme had yet to be completed, I turned to company test pilot Robin Morton for the flying impression. The aircraft can be operated and flown on your own, but an assistant is a bonus, especially to help with the rather undignified process involved in climbing into the cockpit. Robin boards via a specially-made aluminium ladder - one modification GSAL may make is the incorporation of a drop-down section with an inbuilt step in the inboard trailing edge. Further assistance in the form of wing-walkers is also a good idea, as this is a very light aircraft (though when brakes are fitted, ground manoeuvring will be much easier).

Robin recommends a cushion for the basic wooden seat. A four-point harness is standard. Rudder pedals are not adjustable and neither is the seat. There is a small Perspex windscreen, but goggles, helmet and a wind-proof suit are essential.

Instrumentation carried on the surprisingly large panel can be as minimal as you like, but GSAL provides a package of 57mm diameter instruments, including ASI, compass and slip-ball. Because flight testing is in progress, the company’s aircraft is also kitted out with a hand-held radio and stopwatch, but there is still panel space to spare. With the assistance of Stroud-based neighbour Hercules Propellers, GSAL has experimented with props of different dimensions, settling on a large-diameter 70 x 35 unit that works well with the bluff cowl.

On the crisp, clear January day of my visit Robin took the Eindecker up to 2,400ft - the highest he has yet flown - managing to achieve a 600fpm climb at 45mph. He also flew some steep turns for the first  time, up to 45� of bank and beyond (previously tightest manoeuvre had been to 25�) and declared after this that the flying characteristics were “perfectly normal, almost benign”. The maximum speed achieved so far is 65mph at 4,700rpm. Cruise is in the region of 50-55mph at 4,000rpm, the stall quite gentle at 29mph.

So far GSAL has used the hard runway at Aston Down, on which I would estimate the takeoff run to be around 200ft. The noise level was minimal and would certainly not disturb sensitive neighbours. In approach configuration with the pilot sitting quite high in the cockpit, the engine, machine-gun (if fitted) and cabane do not, I am told, significantly obscure the forward view. Touch-down speed is approximately 30mph, and a three-pointer is the preferred landing method. The landing roll was quite lengthy on the hard runway, but the brakes will address this.

A fun aircraft

The GSAL Fokker E.III Eindecker is a charming, fun aircraft made by practising UK microlight pilots with many decades of experience in the aerospace industry. You are not going to tear about the skies in your Eindecker, nor go touring in it, but highly affordable fun flying can be guaranteed.

GSAL are not resting on their laurels and anticipate the outcome of the European Light Sport Aircraft discussions will be that other aircraft from the Airdrome Aeroplanes range can be imported, modified to become UK compliant and put in to the air to counter the ‘Fokker menace’!