SD-1 Minisport
I visited Southern Moravia (Czech Republic) in September 2014 to investigate a stunning fixed wing single seater, the SD-1 Minisport.
SSDR – Single Seat Deregulation – is now starting to assert itself in our sport, following the major concession, in which the BMAA played a leading role, that heavier single seat microlights could be deregulated. We had previously been restricted to an empty weight of 115 kg, accompanied by a maximum wing loading requirement of 10kg per sq m. For certain types – especially fixed wings – it was difficult to meet the empty weight restriction, and the wing loading requirement resulted in a lightly loaded structure which was sensitive to weather conditions. The recent concession, let’s call it “SSDR-max”, increases the take off weight to 300 kg, there is no longer an empty weight limit – but there is now a maximum stall speed requirement of 35 knots (40.3 mph). The former stipulations about wing loading have however been abandoned.
Most of the emphasis in SSDR so far has been in the weight shift area, with several already meeting the criteria and others that could be readily adapted. The fixed wing scene has been less represented so far in these developments.
Against this background, and when I was attending the Tannkosh event in September 2013 in Germany, a spritely little fixed wing single-seat design caught my eye – the SD-1 Minisport, designed and manufactured in the Czech Republic by Igor Spacek. Our SSDR-max concession hadn’t been granted at that point, nor were the likely final terms clear, but it was all in the pipeline and it occurred to me and no doubt to others that a favourable regime could open the door to interesting imports from Europe and elsewhere, especially in the fixed wing area.
And so it was, over a year later, and with our SSDR-max framework now in the bag, that I found myself flying to Brno, in the Czech Republic – but not in my trusty SkyRanger on a misty October day I hasten to say – for the onward journey by car to Hodonin, where Igor Spacek has his factory. Hodonin is about as far as it is possible to go in the Czech Republic without going over the border into Slovakia – more of this later. Apart from wanting to pursue my journalistic endeavours, there was a degree of self-interest in this trip, as the impression made on me by first acquaintance with the SD-1 Minisport had remained intact, and I found myself with a long list of questions I wished I had asked at Tannkosh. One basic question was whether my short but bearlike frame would actually fit the slim cockpit.
As SSDR-max is governed by a new set of legal requirements it’s worth saying something about that at this point, although the rules are simple and straightforward. The take off weight limit of 300kg is self-explanatory – there are higher limits for variants such as float planes and aircraft with ballistic recovery systems but that lies outside the scope of this piece. Whilst the UK requirements no longer stipulate an empty weight limit, most factory-builds or kits will specify a model-specific MTOW, which is 240 kg for the SD-1. This should give a useful payload of between, say, 110 and 120 kg depending on the SD1 model and specification. There is also a pilot weight limit of 105 kg. I was mindful that a more problematic area of our new regulations could be that of stall speed. When a UK owner registers an SSDR aircraft with the CAA, owner-declarations about MTOW and stall speed have to be made. Both could be challenged in the future so it’s a good idea to be confident that both measures could be demonstrated if such a challenge were to be made, otherwise you might perhaps end up with a useless asset. The manufacturer’s MTOW has no direct legal relevance to a UK SSDR, as 300 kg is the basic legal UK limit - although flying above the manufacturer’s MTOW could put you in breach of the stall speed requirement - but it’s a good idea anyway to observe the manufacturer’s MTOW since there may for example be insurance issues if a claim arises. One of the attractions of the SD1 Minisport to a UK purchaser is that it has been approved under German regulations, which include satisfying a stall speed requirement. There is therefore ready documentary proof that the type has been shown officially to meet a measure consistent with our own SSDR-max stall speed requirements. For the avoidance of doubt, it would be worth asking the manufacturer to provide a document confirming a stall speed of less than 35 knots CAS and Igor is happy to provide such a document to purchasers of the SD-1. There is however one SD-1 Minisport recently registered in the UK and the CAA have told me that they would regard this as a precedent for other imports of the same type. It’s worth bearing this issue in mind when considering other foreign import single seat microlights because they may not so obviously meet this measure.
The main website is at www.sdplanes.com and there’s a lot of information there about the different models and engine choices, including factory performance data. There are three basic models, two with tricycle undercarriage (one version steerable) and a taildragger. The taildragger seems to be the most popular, it is arguably best looking and with least weight and drag it out-performs both of the tricycle gear versions. For those of us without taildragging time, though, learning to fly a nimble single seat taildragger introduces a further challenge. All models are available with a higher canopy for the taller pilot. Recent airframe developments include a tinted bubble canopy to replace the capped variety usually seen on the SD-1. Under the cowling there are five main engine choices, ranging from a four-stroke Briggs & Stratton 24hp up to a Hirth F23 50 hp two-stroke. This Hirth version stonks along at well over 100 mph at cruise setting and uses 8 lph at this speed – hardly an extravagance! The less powerful four-stroke versions (B & S 24hp, Kohler 31hp and Verner 34hp) use rather less fuel – the Kohler for example sips fuel at a stingy 4.5 lph in the cruise at just under 90 mph. This puts the small (either 28 or 34 litres) fuel tank into context of course. There is also the smaller Hirth F33 28hp two-stroke engine to complete the list of engine options.
Igor Spacek first conceived the idea of the SD-1 in 1999 and concluded the design a few years later. The aircraft has been popular in Germany and France and there are now over 40 examples flying with many more under construction. Demand for ready-to-fly aircraft has however increased recently over kit-builds, the tail wheel version tending to be the most popular variant with customers favouring the American Kohler four-stroke power plant. A new aircraft ordered now as a ready-to-fly is however unlikely to be available until March 2015.
Spacek s.r.o’s workshops are not large – they employ six people – but the facilities are well ordered and I could see about four SD-1’s at various points of manufacture. Aircraft can be supplied ready-to-fly, or in various kit stages, or in plans for those who want to do all the work. The airframe is made of wood, with carbon fibre reinforcement in key areas such as wing spars, so there was a good opportunity for me to examine the workmanship of pieces in progress. The finish on the completed aircraft looks like plastic and it’s hard to believe that, apart from the cowlings at the sharp end, and the clever use of rigid synthetic foam in the stylish upturned wing tips and on leading edges, the airframe is covered with very thin plywood (down to 0.8 mm ply in some areas.) Each wing has seventeen closely spaced rigid synthetic foam ribs. This material is light but provides the basis for a solid structure. A lot of work and hand finishing then very obviously goes into securing a high quality finish. It’s possible to store the aircraft with the wings off and detaching/attaching them is a very simple process which takes a matter of minutes for those who have limited hangar space or who might want to keep the aircraft in a trailer, for example. Some of the design is compellingly straightforward – the idea of a sight tube for fuel on the panel right in front of the pilot is both simple and very effective.
Although it was a blustery day, I especially wanted to see the aircraft in action so Igor and I made our way to Holic, where his flying operations are based. This involves an international journey of just a few kilometers across the border into Slovakia, the border being noted halfway across the bridge over the river marking the frontier. Two countries then for the price of one – but a completely seamless progression with no formalities of any kind.
We wheeled the tail wheel demonstrator out of the hangar and with Igor at the controls it was ready to go in less than five minutes. Before this I had levered myself into the cockpit and, although it is understandably snug after the expanses of space in a Skyranger, I had good shoulder room. The pedals are adjustable and there is a strong feeling of being at one with the aircraft. No heater, but the small cockpit is well sealed and there would be good solar gain through the canopy – perhaps too much on a hot summer day though, but there is a side vent. Being accustomed to 100hp in my Skyranger, and operating from a fairly short strip, I was keen to see how well the 31hp Kohler would perform. On a very rough surface and with quite long grass, the wheels came up at 170 meters and the aircraft was well clear of the imaginary 15 meter obstacle within its stated distance of 260 meters. I could therefore tick this box on my long list of questions and there is further scope for improvement with a slightly finer pitched propeller.
Regarding prices, a baseline ready-to-fly aircraft can be bought for EUR19,000 ex- works and VAT, but there are many choices of engines, avionics, instruments and other options. Kits range from plans only (you must however buy certain components which cannot be manufactured at home such as wing spars) to almost completed aircraft, priced accordingly. A “reasonable” budget for ready-to-fly, delivered by road to the UK, with a mid range engine and with the usual fitments such as spats, including an 8.33 panel radio but excluding a BRS system, would be around EUR 29,000 including VAT. After that you are in the hands of the foreign exchange market. Let’s say about £23,000 at current exchange rates.
Did I buy one? I’m not noted for my patience and I wanted one immediately! – so the idea of having to wait until at least March 2015 for a new factory-build didn’t immediately appeal to this side of me. However, I was aware that Igor was looking to sell his factory demonstrator – shown in flight in the header photo above – with less than 200 hours on the airframe and with a Kohler engine. This tail wheel design ticked nearly all the boxes for me – and the new style bubble canopy could be retrofitted – I guess the only downside might be a need to make a new panel if I wanted a reconfiguration in that department. Something I could perhaps consider later.
As I conclude this report – which I expect to follow with a further submission later – I can tell you that a large crate will shortly be leaving Hodonin to make its way nearly 1,000 miles by road to me at Whitehill Farm. With an unfamiliar aircraft and at a time of year not always favourable for flying over dense German forests I decided to leave the delivery in the hands of professionals – but I’m now itching to welcome that box and to assemble the contents. And there is no shortage of WFAeC insiders to help me to perform that task. The next step will I hope be to report the results of a detailed flight test here in the UK.
Our change in regulation and the introduction of SSDR-max opens the door for all sorts of new machines, including examples from the fixed wing area. The performance of the SD-1 Minisport lies close to the boundary of what is possible within our microlight regulations and I expect it to generate a lot of interest in the UK. It’s now making its debut here and I’m hoping that Igor and the Minisport will be at Popham in 2015 where I’ve warned him to expect a crowd of interested visitors.
