While going through my photo database in search of material for my previous Flying In The Time Of Corona photo file, I discovered that there’s plenty of stuff in there for a follow-up post as well – but this time focusing solely on foreign visitors to Croatia’s many coastal airports (+ Lučko of course). Like our own birds, these too could not be scared off that easily, arriving into the country in quantity and quality rarely seen even in years past. And since it would be rude of me to keep them all for myself, another summer time Photo File is obviously in order! (to build on the two bonus Cessna 172RGs already featured in their own post)
To properly kick off my return here after an unintentional pause of nine months (!), I’ve decided to revisit an aircraft type I had mentioned in passing some time ago – seeing that, by a stroke of sheer dumb luck, I managed to snap TWO in the space of just one week (which is twice as many as I’d managed over the past 18 years). The machine in question – as the post title infers – is the Retractable Gear (RG) version of the common Cessna 172, an aircraft whose rarity and cool factor is matched only by its apparent uselessness and absurdity…
To immediately get an idea of why the 172RG stands out like a sore thumb within the traditionally conservative Skyhawk family, it seems best to start off with its main party pieces, as compared to the stock 172P of the same period (1980):
fully retractable gear
a longer snout to house the nose gear when retracted
a 180 HP Lycoming O-360-F1A6 w/ constant speed prop (vs the standard 160 HP O-320 and fixed pitch unit)
a 66 USG fuel capacity (up from the standard 42)
and a 1,202 kg MTOM (vs the 1,088 of the P)
Performance-wise, the extra grunt (particularly the increased efficiency of the constant speed prop) and cleaner lines meant the RG could pull up to a 20 knot lead over the stock P, with High Speed Cruise pegged at 140 knots. The new prop also made for slightly better after take-off climb performance (800 fpm vs 700), while the increased fuel tankage gave a pretty chunky range boost, from 440 up to as much as 770 NM.
However, the ~80 kg added by the gear retraction mechanism also upped the empty weight, now standing at 740 kg vs the P’s 660. Normally, this was not much of a payload issue if you took on only your required fuel – but if you went all out and brimmed the tanks, you’d be left with barely 260 kg of headroom… roughly two 2020 adult males, some luggage and all the stuff normally carried around when away from home (additional oil, tow bar, cockpit/wing covers, emergency equipment, survival kits, …).
The higher MTOM also made for longer take-off and landing runs, both up by roughly 70 meters even on concrete; and while some owners have been known to fly them out of rough fields (and even back country strips), it generally goes without saying that the new legs did not take too kindly to prolonged use on the types of runways normal 172s take for granted.
The Cessna Retractable Dance. Go to 0:30 for retraction and 1:30 for extension. You’ll note that the pilot leaves the gear down for quite some time after take-off; the standard wisdom on RG Cessnas is to leave it hanging until clearing obstacles, since the retraction sequence causes so much drag it can noticeably impair climb performance at a critical stage (this is also SOP on airliners during windshear escape maneuvers). Indeed, the main legs drop by a whopping 60 centimetres during retraction!
Maintenance-wise, private owners, commercial operators and various incident reports all tend to agree that the upsides of its commonality with the stock 172 are frequently balanced out by the many gremlins of the RG system – though user experiences vary considerably, particularly when comparing leisure and training ops.
Persistent weak spots and items that require frequent inspection are the main electric-driven hydraulic pump, down-stop pads that (if damaged) may prevent the main gear legs from locking down, and the main gear pivots that are worn out by the legs’ aerobatics during retraction and extension. There’s also the need to periodically cycle the gear on the ground during checks – which requires jacks and additional man-hours – as well as the costs of servicing the propeller governor (though that’s a pretty standard job).
And while none of these are deal-breakers in themselves – the 182RG and 210 say Hiii! – the cost-benefit math of doing all that on a lowly 172 did not make the RG everyone’s cup of tea…
So, when all was said and done, the 172RG was a cheap & simple aircraft made expensive & complicated for just a few marginal gains – so much that even the fixed gear 210 HP Reims FR172 Rocket could keep up with it in a pinch (and for noticeably less money). What’s more, if you really wanted the “Full RG Experience”, five numbers up was the (slightly) more powerful, (much) more efficient, (oodles) more comfortable and (far) more elegant 177RG Cardinal – an aircraft conceived outright for the touring role, offering 182 series frills without many of its financial chills.
The 172RG thus appears to be – in technical terms – a complete crock. However, outright performance and mass market appeal are not what this airplane is about; its forte was to corner a very specific niche of the training market by offering a suitable and affordable “quick fix” for a problem few manufacturers seemed interested in tackling.
The niche in question was for what’s termed a complex aircraft, a surprising demanding specification that calls for a simple, easy-to-fly, robust and cost-effective airplane that can also boast toys such as flaps, retractable gear and constant speed props – all the complicated and fiddly stuff that future airline drivers are supposed to deal with (did mine on an old, student-weary PA-44, so the full set of traumas is there!)*.
And with the Skyhawk’s 25 years of active service to its name, the type’s well-known middle-of-the-road handling, off-the-shelf components (even the landing gear, nicked off the Cardinal), a reliable and frugal powerplant and a developed global support network, the 172RG had hit all the nails it needed to hit. Even though it would be born on the eve of Cessna’s decade-long single engine production pause, 1,191 would be made between 1980 and 1984… not bad for a niche design!**
* the original specification for complex aircraft had not set a specific minimum power limit; in 1997 however, the FAA set the bar at a minimum 200 HP, thus disqualifying the 172RG. However, the type still remains in widespread use as an introductory platform for more complex touring machinery – as well as a charismatic “left field” personal airplane
** though there are frequent parallels with the Beech 24 Sierra and the Piper Arrow, the 172RG is actually not a direct competitor to either. Both designs boast thirstier 200 HP fuel-injected engines (the Arrow with the option of turbocharging), better performance, more amenities – and are generally set up more for the posh end of the touring market; their closest Cessna analogue would be the aforementioned 177 Cardinal. The only aircraft on equal footing with the 172RG was the very first version of the Arrow – the 180 HP PA-28R-180 – which debuted in 1967 and remained in production for only a couple of years before being superseded by the first of the 200 HP models
What’s in a name?
While all of the above ticks quite a few Achtung, Skyhawk! boxes, one more thing remains that is very worthy of mention: it’s name.
While it does say “Cessna 172” on the tin, the 172RG is techno-legally not a purebred Skyhawk – but rather an offshoot of the nearly forgotten 175 Skylark. Billed as the next step towards the larger 182 (a role that would later be filled by the 177), the 175 was in essence an up-market high-trim version of the 1956 172A, fitted with a geared 175 HP Continental GO-300 instead of the standard direct-drive 145 HP O-300. Unfortunately, reduction gearboxes were at the time an unheard of feature on such a small civilian engine, meaning that very few pilots had ever encountered one before. The specific way in which such an engine had to be handled – flown at around the 3000 RPM mark – was so alien and absurd to private pilots that many drove them at the more usual 2000-2200 RPM, leading to a ton of breakdowns, failures and bad PR. By 1962, things had gotten so bad that Cessna was forced to pull the plug on the entire design, and retire both the 175 designation and the Skylark name…
To salvage at least some of the effort invested in the design, the company decided to keep the 175’s Type Certificate (and some mechanical bits) and use them as the legal basis for all future high-performance variants of the 172:
the 195 HP R172 Hawk XP
the 210 HP Reims FR172 Rocket
the military T-41 Mescalero
and the 172RG
Traces of the Skylark’s original DNA can still be seen in the R172, FR172 and T-41, since they all sport the tall narrow-track landing gear of the 172A, which would be replaced by the squatter wider-track variant we all know and love on the subsequent 172B.
However, this would not be the end of Cessna’s marketing shenanigans; in 1983, the company would launch the 172Q Cutlass (sans RG), an attempt to “schlepp” on the RG image by fitting the 172P with a 180 HP Lycoming O-360-A4N driving a fixed pitch prop. Quite a rare model today – which did not offer much meaningful superiority over the P – only a handful would ever be built before the Skyhawk family as a whole went into its prolonged 80s coma…
While at this point in any normal Achtung, Skyhawk! post I’d go off with a ton of (more or less) descriptive external photos, in this instance I decided to “stay inside”, since the opportunity to snoop around a full-blown rebuild (currently at ~60%) was an opportunity too good to miss! The photos are not my best work – it’s hard to maneuver my 1.91 m frame w/ camera and tripod inside a 172 – but hopefully they’ll be interesting enough for the common avgeek!
As ever, I would like to extend my sincere thanks to Dorian Delić of Medulin Airfield (LDPM) in Istria, for allowing me to snoop through his family’s hangar and drool a bit over D-EGGF!
It is perhaps a sign of the state of general aviation on the Balkans that the arrival of a single Cessna Caravan can stir up so much interest that even people from neighboring countries head over to see it. While a perfectly common “garden variety” airplane everywhere else, the 208 is still a pretty exotic beast in these parts, with myself having come across only four examples in the 16 years I’ve spent hanging around light aircraft. Therefore I could be excused for packing up my photo gear and driving 120 km one way to Šentvid Airfield in Slovenia in order to catch it 😀 .
The machine in my sights, however, had a bit more going for it than just being a big Cessna with a turbine. On the one hand, it is a comparatively rare short-body Caravan I – and on the other it sports the impressive Blackhawk XP42 engine conversion that is not that common even in the more affluent bits of Europe. So as it spent its three days there hauling skydivers to altitude, I could take my sweet time and get to know it Achtung, Skyhawk! style 🙂 .
Though much can be said about the qualities and exploits of the rugged Caravan, what interested me most in this case was in fact Foxy’s nose job. One of the many products to come out of the Blackhawk Engineering works – the people who put third-party turboprop upgrades on the map – the XP42 mod involves replacing the 208’s standard engine (in this instance a “small series” 675 HP PT6A-114A*) with a much more potent “medium series” 850 HP PT6A-42A. In addition to the improved power, the 42’s larger core also noticeably adds to the torque, with take-off figures now up from 2,535 to 3,045 Nm. To soak all this up, the original three-blade 2.69 m McCauley prop gives way to a variety of four- and five-blade aluminum and composite units, with Foxy in particular sporting a conventional 2.54 m Hartzell for a bit of extra ground clearance.
* up until serial number 208-00276, most short-body Caravans were powered by the 600 HP PT6A-114 unit. From aircraft 277 onward, they switched to the same 114A as used by the bigger Grand Caravan. Also of note is PW&C’s engine class system: “small series” engines develop between 500 and 900 HP, “medium series” cover the 850-1,050 range – while “large series” go from 750 all the way to 1,900.
But, the XP42 upgrade is as much about added grunt as it is about the nature of its delivery. Unlike a simple engine swap, this conversion is what’s called a “firewall forward solution”, which includes – where necessary – extensive modification to the engine compartment itself in order to get the most out of the new powerplant. Since the majority of XP42s will be used for rough-and-tough hauling in arduous conditions, the folks at Blackhawk had gone to some length to make the upgrade more than just a course of steroids. To this end, the most obvious alteration is to the cowl, now widened at the front to accommodate a 40% larger oil cooler in order to keep things in the green even during operations in hot-and-high conditions or repeated back-to-back flight cycles. The new twin exhaust stacks (a consequence of the 42’s slightly different architecture) can be profiled to either eek more thrust out of the exhaust gasses (5 knots worth in fact) – or increase mass flow at the expense of cruising efficiency to lower turbine temperatures during the type of prolonged high-power climb common to skydive ops.
Other stuff? Well, the engine is now mounted at four points instead of three, there’s an improved air intake system with a modified inertial separator to further reduce the likelihood of foreign object ingestion at rough strips, the battery is now a Li-ion affair instead of lead/acid to save roughly 13 kg in weight – and there’s an optional 325 A starter generator instead of the stock 200 A unit to reduce wear and tear on the engine by shortening spool up and light up times. The package is also rounded up by custom Hawkeye engine gauges, generally similar to the Caravan’s originals – but now with an additional digital readout for most parameters.
As always, I would like to thank the very friendly staff at Šentvid Airfield – as well as Foxy’s pilot for allowing me to snoop around the aircraft inside & out!
While the met office tended to respond with much doom and gloom every time the summer of 2016 came up, out in the (air)field we had mostly been treated to beautiful flying weather all throughout the season, with gorgeous conditions from dawn all the way until the last dusk. This had particularly been true for the week preceding this article, with a large high pressure area over Europe responsible for skies clear as far as the eye could see (even from the flight levels).
Unsurprisingly, this turn of events had lured out many light aircraft all throughout the region, with plains, seas and hills alive with the sounds of pistons. By sheer good luck, this fine spell had seen me travel all over the place, allowing my camera to see what our little piston singles – and gliders – were up to… 🙂
While I normally shy away from sombre themes, on this one occasion I’ve decided to make an appropriate exception. The unfortunate circumstance that had led to this change of tone is the fifth anniversary of the destruction of Cessna T303 9A-DLN, which had been lost with all on board in a ground impact accident on 5 February 2009.
On occasion flying out of Zagreb Intl, DLN’s mission that day was a multi-engine proficiency check, which had called for a cross-country VFR flight to Zadar’s Zemunik Airport (LDZD). The on-board complement had included:
Miljenko Bartolić, Pilot-In-Command, a much-loved examiner and former agricultural and airline pilot who had given me my PPL wings back in 2002
Gerd Govejšek, instructor (manning the co-pilot’s seat), also well known to many generations of student pilots at Lučko
Aleksandar Walter, passenger, a highly experienced former Police helicopter pilot and CO
Zvonko Kelek, passenger, a private pilot with aviation experience dating all the way back to the 80s and Yugoslavia’s national carrier JAT
According to the official accident report – available, in Croatian, here – the flight had proceeded normally until reaching the vicinity of the town of Gospić, located near the foothills of the Velebit mountain range and about 5/6s of the way in towards Zadar. At this point, DLN had entered an extensive area of cloud, moderate icing and mountain waves, eventually ending up in continuous Instrument Meteorological Conditions (IMC). However, the crew had elected to continue their flight to Zadar without a change of route, altitude or flight rules, likely relying on the aircraft’s comprehensive IFR instrument suite and wing and tailplane de-icing systems.
Approaching the Velebit range at 8,000 ft – a safe terrain clearance altitude even during moderate wind – the aircraft had entered an active military training zone (normally open to civilian traffic and only activated when the Air Force actually needs it), after which it was instructed to descend below the zone, whose lower boundary was at 6,500 ft. This new altitude had put DLN at between 800 and 1,300 ft above the approaching peaks.
Though there is still a degree of uncertainty acknowledged by the report, it states that the prolonged flight in cloud had led to extensive airframe icing, likely starting around the tail. Still flying at 6,500 ft, DLN had then entered an area of severe mountain waves, which had produced a strong and rapidly increasing rate of descent. Iced over and too heavy to counter it, the aircraft had quickly begun to plummet, impacting the mountainside at 4,734 ft, roughly 1,000 ft below Vaganski vrh (Vagan Peak). The final radar contact was recorded at 14:54 local time.
The report notes that the impact was so violent that the aircraft had virtually disintegrated. The search for the impact site – as well as the subsequent recovery of the wreckage and bodies – was hampered by bad weather for days, in addition to an avalanche that had buried most of the immediate surroundings.
Having lost four of its much loved members in an instant, the aviation community at large fell into a state of shock and bewilderment – a state that persists even today, five years on. The death of four experienced aviators – and the conditions into which they had flown – have left a lasting mark on all of us, now unable to look at the Velebit range the same way ever again…