A jack of all trades

Tim Robinson has a look at the Grob G180 SPn Utility Jet, an aircraft that offers the performance of a jet and the capabilities of a turboprop.

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By  Neil Denslow Published  November 1, 2005

A jack of all trades|~|Grob2.jpg|~||~|Go to a remote and dusty airstrip anywhere in the world, and you can guarantee that one of three aircraft will eventually turn up. Either the dependable Cessna Caravan — with over 1500 sold — the ubiquitous Raytheon King Air — 5000-plus sales — or the flexible Pilatus PC-12 — over 500 now flying — is sure to land there, if you wait long enough. All of these are solid, rugged workhorses that are all equally happy transporting VIPs, evacuating medical patients or delivering supplies. There are also all turboprop-powered. But there is a sleek new competitor on the horizon — and one that aims to break into this niche market of dependable, go-anywhere, do-anything aircraft. German composite manufacturer Grob, in partnership with business jet operators, ExecuJet, is intending to shake up this market with its new G180 SPn Utility Jet, an aircraft with the flexibility of a turboprop, but the performance of a jet. Both companies foresee that the Utility Jet will not only appeal to pilots and owners of turboprops wanting to trade up, but that its combination of long range, short field performance, large cabin, and affordable price tag will, in fact, drive extra demand for this unique aircraft. Genesis of the concept The G180 made its public debut at this year’s Paris Le Bourget air show after a swift and highly secret development process at Grob’s facility in Germany. With its composite no-rivet fuselage and smooth lines, many passer-bys at the show were fooled into thinking that Grob had brought a full scale model, instead of the real thing. Even more uniquely, the jet had been quickly dissembled before its shipment to Paris. So why the Skunk Works-type secrecy over the project? Grob and ExecuJet explain that in their case, having not built a business jet before, it was better to ‘under promise and over deliver.’ The genesis of the G180 is an interesting one. Grob was originally in talks with ExecuJet over its G160 Ranger, a six-passenger business turboprop, which is still in development, but now at a slower pace. Discussions, however, led to the kind of aircraft that ExecuJet Aviation Group’s CEO, Niall Olver wanted to see in the market. Olver’s specifications were long range, short field capabilities and a large cabin. Hearing this list, Grob set about turning these ideas into reality. Grob, of course, is well known for its experience in advanced composites technology. Christian Grob, the company’s chairman & CEO, and the son of Dr Burkhart Grob, the company’s founder, is extremely proud of Grob’s record in composite aircraft, especially the high-altitude research aircraft Stratos 2, which still holds the world record for the highest-flying piston powered aircraft. The company’s current range of aircraft includes the G115, which is used by the RAF in an elementary flying training role; the higher power G120TP, which is equipped with a Lycoming AEIO-540-D4D5 engine; the G140TP four-place fully aerobatic trainer and tourer; the G160 Ranger business turboprop, and a range of gliders. The company itself employs some 5000 workers in all — 3000 people in its aerospace division, along with another 2000 employed in Grob’s machine tools division which makes machine tools. Its main headquarters is situated southwest of Munich, in Bavaria, where it has its own private airfield for testing. In the G180 deal, Grob agreed to design and manufacture the aircraft, with ExecuJet providing the sales, marketing and distribution. ExecuJet has a global business aviation network, including fixed base operations (FBO), sales, chartering and maintenance divisions in Zurich, Frankfurt, Dubai and South Africa among others. Its Middle East operations are based as its regional headquarters in Dubai, where it has sales franchises for Bombardier, Pilatus and Grob. The company also recently finished work on an FBO and maintenance base in Dubai, which will be officially opened during this month’s air show. Development As well as being unusually secretive for the business aviation world, the development of the G180 has also been exceptionally swift. It was only in January 2004, for instance, that the project was officially given the go-ahead. In September 2004, the engineering designs were finalised, while a month later in October, the first composite fuselage was completed. Static tests began in February 2005, while in March, final assembly of the first prototype began. Three months later, in June, the wraps came off at Paris, to the surprise of the media and delight of Grob and ExecuJet. Interest at the time was phenomenal, says Grob, with the aircraft being the business aviation news story of the show. Finally on 20 July 2005, the G180 SPn made its first flight. The 66 minutes long flight from Allgau Airport in Germany tested initial handling and system checks, and the aircraft reached 9500 ft. Not bad for a project which had only been started a year and a half ago and especially remarkable in today’s long-cycle aerospace programmes. Grob’s chief test pilot, Gerard Guillaumaud, describes the first flight as a ‘non-event,’ and adds that the subsequent test flights have also given him ‘little to tell his grandchildren about.’ “Essentially, [on the first flight] we try to take the aircraft into the air and back without it noticing,” he explains. Proof of the smoothness of the test process must be that the company gave the go-ahead for the maiden flight after only two high-speed runs, despite six being planned initially. The G180 is now undergoing a full flight test programme, expanding its performance envelope up to 41,000 ft, as well as testing the low approach (105 kt) and touchdown (90 kt) speeds that confer its outstanding short field capability. With flight tests now proceeding apace, certification tests are scheduled to begin in the second quarter of 2006, with European EASA certification and US FAA certification on track for early 2007. First deliveries are also set to begin in 2007. Performance One of the key differentiators of the G180 is its performance — especially in its slow speed and short field capability. The aircraft features a relatively large wing, which is equipped with powerful Fowler-flaps. These enable it to achieve almost turboprop like short field performance, thereby opening up a large number of airfields around the world that were previously out of bounds to jets. Indeed, at a Grob press briefing in September, the G180 landed in marginally less space than the turboprop-powered G160 Ranger. The G180’s stalling speed is a docile 77 kt and the maximum operating altitude is 41,000 ft. The aircraft also boasts a range of 1800 nm, with six passengers and one pilot, which is enough to fly from Dubai to Colombo, from Cairo to Paris or from Casablanca to Lagos. One area where Grob and ExecuJet have had to compromise — in large part because of the thick wing that holds the fuel — is in speed. The aircraft is equipped with two Williams FJ-44-3A 3000 lb turbofans with FADEC, which, despite endowing the G180 with excellent short field performance, only give a maximum cruise of 407 kt at 33,000ft. Similarly, the maximum operating Mach number is 0.7. Grob and ExecuJet are upfront about the way in which speed was balanced out against other performance parameters, such as range and short field capability. They are confident though that the type’s unique properties and its speed advantage over turboprops will more than offset the fact that it is not as fast as traditional jets. Structure Another unique feature of the G180 is its rugged composite construction, which gives strength, simplicity and lightness, and leads to its highly smooth and unriveted appearance. Thanks to composites, the fuselage has a slightly egg-shaped cross-section, which gives passengers more width at shoulder height, just where it is needed. Proof of the over-engineered strength of the fuselage is that initial static tests revealed that Grob could also use it as the basis for a high altitude surveillance aircraft, the G600. This aircraft, which would be able to operate at 60,000 ft, is an optionally manned aircraft able to perform Global Hawk-type missions at a fraction of the cost of the US UAV. The G180’s fuselage is attached to the wings by four large, extremely robust titanium bolts, which also allow the aircraft to be dismantled for transportation or inspection. Indeed, this was the method in which the prototype was shipped to Paris. Grob also boasts that it only takes five people two hours to dismantle the jet — not something you could say about a conventional executive jet. However, do not let this ease of disassembly fool you into thinking the Utility Jet is some kind of homebuilt aircraft. The airframe is extremely rugged and has been specially designed to cope with unprepared airstrips. The undercarriage, for example, is made of titanium by Grob inhouse and it features a reinforced trailing link design for harsh environments. Furthermore, the carbon composites used means the aircraft is highly crashworthy and fatigue-resistant. Cockpit and interior Moving to the inside, in the cockpit the production aircraft will be equipped with a Honeywell Apex integrated avionics system glass cockpit as standard. This incorporates four large displays — two 15 inch primary flight displays (PFDs) and two smaller 10 inch multi-function displays (MFDs) for maximum situational awareness. EGPWS (enhanced ground proximity warning system) and TCAS (traffic alert & collision avoidance system) will also be a standard fit and although the aircraft will be certificated for single pilot IFR operations, the avionics fit will also include dual FMSs. Inside the passenger cabin, the room available — 11 m3, according to the brochure — is first thing you notice. In the standard configuration, eight passengers can be accommodated in this space sat in a club class layout. The toilet is at the front of the passenger cabin, opposite the entry door. Once in flight, a couple of panels fold into place to create a toilet cubicle, the full width of the aircraft. However, the interior can also be re-roled in just an hour to a new configuration — either cargo or a mixed cargo/passenger layout — which gives maximum flexibility to the operator. The Utility Jet also features a larger than usual entry door (53·9 in x 33·1 in), which Grob hopes will win over converts from the Caravan and King Air communities. With these practical characteristics, the potential uses for the G180 are almost unlimited. A wide range of applications, such as air ambulance, special missions and overnight delivery, are all certainly possible. A new class? But, can the G180 SPn Utility Jet really succeed in creating a new class of aircraft in the highly competitive business aviation market? Its US $7·1 million price tag is affordable, but Grob and ExecuJet are keen to stress that the aircraft, unlike the Eclipse 500, for instance, is not aimed at the entry-level buyer. Instead, they anticipate that the majority of owner/operators and pilots will have experience on either jets or turboprops. They also see the overall demand for small aircraft growing following the launch of the G180 rather than it having to compete in a static market. “With its combination of real jet utility and superior cabin, as well as its exceptional performance capabilities relative to its acquisition and operating costs, the SPn will grow, not displace, the light aircraft market,” says Peter Smales, executive director, marketing, ExecuJet. Grob and ExecuJet are cagey, however, about exactly how many G180s have been sold since the aircraft made its public debut at Paris. The first year’s worth of production, 15 in 2007, is accounted for though. This rate will climb to 25 in 2008, and then move to 40 aircraft a year from 2009 onwards. The two backers also point out that, so far, marketing and promotion of the aircraft has been focused on Europe, so these sales figures are likely to rises substantially once the Middle East and, especially the US, are taken into account. It should not be long, therefore, before people waiting at dusty airfields around the world start to hear the roar of a jet engine rather than the whirl of the turboprop that they are used to. ||**||

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