flyer eurofox

8/12/2019 FLYER Eurofox

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022 FLYER DECEMBER 2011

Aeropro EuroFOXFLIGHT TEST

AeroproEuroFOX

Justin Coxappreciates anair of renement

and quality about the tube-and-fabric, factory-assistedhome-built EuroFOX

M

y rst impression of the EuroFOX washeavily inuence by the awless rednish of our test model, which exudedquality, but there was also a feeling of

familiarity with the design. Aeropro, the Slovakianmanufacturer of the EuroFOX, having built an Avidin 1990, metricated it and re-engineered it intothe EuroFOX, making no attempt to hide the history.

Effectively, all that remains of the originaldesign are the aperons, folding wings and a hintof its original aesthetic heritage. I feel this aircrafttenuously owes its design to the Monocoupe, theinuence of which is clearly seen in the Avid andthe later breakaway, rened version, the Kitfox.The Avid n and the Kitfox cowl, for example, arevery Monocoupe. Its clear that Aeropro wanted totake the Avid sentiment and rene it into a muchbetter package all round 20 years on and withsome 150,000 ight hours experience, I believethey have achieved this goal.

The EuroFOX follows the traditional Avidconstruction of tube-and-fabric. But the wingsare a departure, utilising similar tubularaluminium front and rear spars as the Avid butwith a composite, shaped leading-edge on theEuroFOX supported by the front spar andaluminium ribs instead of wood. Also theunder-cambered ribs are gone, utilising a simplerat-bottomed section. Fore-and-aft stiffness isprovided by steel drag tubes zigzagging betweenthe front and rear spars adding to the wingsrigidity, just as used by the Avid.

Each wing houses a 40lt aluminium tank atthe root, so there is no fear of fuel damaging thetanks, as would be the case if they were made ofa composite (non-aluminium) material.Composite mass-balanced aperons hang fromthe trailing-edge on four L-shaped hinge brackets,in a similar manner to the Avid and Kitfox. Thefuselage is welded steel tube, internally treated

with oil, and is sandblasted before double-polyurethane-coating by the factory.

Aeropro has chosen to cover the EuroFOX withPoly-Fiber, the weight of the fabric beingdependent on the regulations under which theaircraft is certied. For the LAA version, medium-weight fabric is used. For the more weight-criticalBMAA version, light fabric is used.

Roger Cornwell, the UK and Ireland distributor,explains that the very high quality of nish onG-CGYG is no accident. The company wassceptical when approached by Roger about apossible home-build version. They thought thatthe quality of nish may be compromised. Ahalfway house was found; the builder goes to theAeropro factory in Slovakia, and spends a weekunder supervision covering their aircraft. Thebuilder doesnt need to purchase any tooling forthe fabric work, and hasnt got the worry oflearning to cover. At the end of the week, the


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cartoon-like nose bowl to feed a large waterradiator. The oil cooler installation also adds to thesleek traditional cowl look, being fed by a NACAduct on the right side of the cowl. The cooler ismounted very neatly on the side of the cowl,taking minimal space. Careful examination revealsa Bowden, pilot-controlled ap on the entrance tothe oil cooler, allowing for faster warm-up timesand more precise oil temp control. Maybe athermostat would be a far better solution; butsimple is good.

On the opposite side to the oil cooler,another NACA duct feeds the engine with air.Bowden-controlled carb heat is arranged in asimilar style to the oil-cooler ap, blocking theNACA duct and forcing the engine to draw warmair from inside the cowl, freeing the exhaust heatexchanger for heating the cabin alone. Despitewhat people say, Rotax engines do suffer fromcarb icing, so it will be interesting to see if the air

from inside the cowl is sufcient to hold off carbicing on ideal carb icing days.

A very smart carbon airbox is mounted on therewall, feeding each carb via a rubber hose. Thiswill increase the life of the carb inlet rubbers bysupporting the carburettor on the intake side.When the carbs are tted with individual K&Nlters, they get a very hard life and usually requirefrequent replacement. (Anyone who has watcheda Rotax idling, especially with a carb imbalance,will know how much the carbs shake about.) Thecowl is held on by neat and easy Camlocs, but thebottom cowl removal will be hampered by thewater radiators and oil cooler being xed to thecowl, requiring disconnection of front-mountedtwin landing-light loom, Bowden controls for thecarb heat, and oil-cooler ap.

Wing-fold is very much in the same vein as theEscapade. This is a one-man operation, whichRoger demonstrated with ease on the blustery day

of the test. Unlike the Trail, the width with thewings folded is well under the legal trailer width,allowing easy road transport.

Viable tourerEntering the EuroFOX is easy with the typicalbum on the seat and swing the legs in technique.The top-hinged, fully-glazed door is held under thewing, just clear of the fuel tank outlet union, by agas strut.

Once seated, its clear that theres plenty ofroom for the pair of us, including ample leg andheadroom. The seats are xed, offering no meansof adjustment. The factory tackles this problem byoffering different depths of seat squab and backupholstery. Roger tells me he has a customer whois 6ft 3in who ies with the reduced cushions andhas ample space.

Being a blustery autumn day, I elect to closethe door and to take advantage of the solar



Lots of panel space for the ownerto get creative with personalised

avionics. Note cavernous handyglovebox to stow items


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heating through the clear roof panel. The centralrotary door-handle latches the door shut at thebottom and, via a Bowden cable concealed in thedoor frame, secures the door with a pin at the rearof the door. The design and action of the doormechanism oozes quality.

Strapped in with the four-point, car-typeharness, I notice that the lower right of the panelis dominated by a cavernous open gloveboxangled slightly downwards to prevent items fallingout during ight. This is lined with sympathetically-coloured velour. For this demonstrator, Roger hadopted for a fully loaded aircraft, including steeringdamper, soft start, oil-cooler ap, cabin heatingand carburettor heat.

At the time of this test ight, YG wasundergoing glider-towing tests, so also had manyoptions that wouldnt suit the average customer including a large T-handle glider hook release andan extra cooling shroud around the air-cooled

portion of the cylinders. The EuroFOX has provenits worth as a glider tug in many countries,launching gliders up to 750kg.

Despite the loaded state of YG, with a zerofuel weight of 300kg, it still had a payload of260kg. On the day of the test, Roger and Iweighed in at 200kg, with 2/3 tanks on boardequating to about 57lt or about 41kg of fuel,meaning we had an endurance of about 3hr50min with a half-hour reserve, equating to 383miles at a sensible economy cruise. At this testweight there was still capacity if required to use19kg of the allowable 20kg in the baggage bay.This clearly is a viable touring machine.

Analogue ight instruments are placedsquarely in front of the pilot, with the rpmsituated directly beneath the airspeed.Guarded mag switches are positioned just to theleft of the airspeed. The key-operated masterswitch has four positions: Off; Avionics; Engine;

and Starter. The Avionics setting allows for theavionics to be turned on without powering theengine circuits, presumably for the programmingof GPS devices, etc. The right-hand side of thepanel above the glovebox contains the engineinstruments, with electric switches and breakersabove that. An optional cigar lighter socket,protected with a 5amp breaker, is on the far rightof the panel.

The centre of the panel is dominated by anAirbox Foresight, which combined with the greatvisibility must make getting lost nigh impossible.A neat Filser VHF com and transponder sits belowthe central Airbox. Engine controls are all groupedtogether at the central lower panel, dominated bya most awkward vernier throttle that would surelybe better suited to actuating a trim tab. Anexcessively large T-handle pull, twist and lockchoke Bowden is situated to the right of thethrottle. Below nestles the red T-handled glider

DECEMBER 2011FLYER 025


Note the wide-track undercarriage,making for a stable ground handling

platform. Combined with powerfulcontrols the EuroFOX should handle

crosswinds with ease. Roomy,comfortable cockpit is aided by the

fully-glazed bulged entry doors.Mirror on the port wing is

for glider-towing duties


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release handle, next to which are matchingcontrols for carb heat, cabin heat and oil coolerap control.

The fuel system consists of in-line fuel cocksfor each tank, situated high on each door entrypost, both feeding to a single master in-line on/offtap situated just below the left-hand side of thepanel. Fuel is fed from the main tanks into acollector tank, situated under the pilots seat,which contains six litres of fuel. A warning light,situated above the altimeter, illuminates whenonly four litres of fuel remains in the collector, asure sign it is time to land if the main tanks areexhausted. A push-to-test button to the left of thewarning light enables the circuit to be tested. Maintank fuel gauges are of the simple sight-tube type,situated in the wing roots. These are not calibratedon YG, but I suspect some form of calibration willbe incorporated in the kits. YG is tted with theoptional fuel boost pump, installed as part of theglider tug kit. Apart from the low collector tank,head pressure from the wing tanks should ensurethe engine is fed with fuel should the enginepump fail.

Healthy climbStarting the Rotax proves simple, smoothly aidedby the soft start module. Oil-cooler ap closed, Iuse the wait for the engine to warm to familiarisemyself with the view from the cockpit. To thesides, the slight forward sweep on each wing isevident. Forward swept wings can offer somemajor aerodynamic advantages, which are usuallyovercome by structural inadequacies, but thissweep is minimal and only used as a cunning trickto help the C of G range.

Oil temp in the green, we taxi out. Thecomposite gear soaks up the uneven surface ofthe strip, giving a very comfortable ride.Nosewheel steering is via Bowden cablesconnected to the rudder pedals, and is easy andprecise, unlike the vernier throttle, which Imalready starting to dislike. With temperature andpower checks complete, I select half-ap asindicated by a mark on the fuselage tube that hasstops for ap up and full down positions. Theap lever is innitely selectable between up anddown and is held in position by friction alone.

Correctly set up, it should mean that overspeedingthe aps is impossible; they should overcome thefriction and self-retract.

Control checks show that the ap aileronmixing unit to be working correctly. With the fuelpump engaged, oil-cooler ap open and after abrief carb heat check I apply full power.Acceleration is good but we are not producing thefull power potential of the engine. Settled in a full-throttle climb at 75mph with the aps retracted,the engine rpm is only at 4,800 rpm equating toabout 87hp. Being well below the max continuousrpm limit, I can leave the throttle wide open.Clearly the aircraft is over-propped, but it doesntappear to be too detrimental to the aircrafts eldand climb performance; we have a healthy800fpm climb at about 19kg below max weight.

Its time to get on station for some photos,and my dislike for the vernier throttle climaxes;keeping station with the camera ship requires aquick twisting hand action this is unlike mostvernier throttles and their traditional grip methodof depressing the vernier lock with the palm ofthe hand

Photos complete, I break away to performsome general handling. Full throttle and settled on

the step, I manage to see 5,300rpm, whichindicates just shy of 130mph at 3,000ft. Its myguess that it would be a fair 125mph, due to thethermic activity of the day. Easing back to a moreleisurely economic cruise of 4,200rpm gives anindicated 100mph. Roger estimates a fuel burn ofabout 11 litres per hour at this cruise setting

Next, I check for the aircrafts natural stability.Most well-designed aircraft y happily withoutinterference from the pilot, if trimmed. TheEuroFOX is no exception; hands and feet off onthis bumpy day results in the aircraft continuingsteadily at 3,000ft and on heading. Turning myattention to the rudder, I initiate a turn with rudderalone. The EuroFOX dutifully rolls in the directionof the applied rudder. Releasing the rudder revealsthat it has a tendency to want to stay where itsleft, without any natural centring. Roger tells methat the LAA had increased the height of the nand has asked for rudder centring assist springs tobe tted to the rudder bars.

From straight-and-level, introducing a brieftransient rudder input also reveals the EuroFOXsindifferent attitude to yaw stability. Feet off therudder and initiating a turn with aileron alonereveals a true design triumph, almostunperceivable adverse yaw, with the nosedutifully following the desired turn direction.Co-ordinated turns are a breeze, with the lackof adverse yaw, and seem equally effective at allap settings. Flaperons have a reputation forlosing effectiveness as ap is lowered, but theseseemed to respond beautifully. Roger informs methat the factory has limited the ap deection,which has helped alleviate the problem. Steepturns are met with a reassuring, progressively-building stick force, giving excellent stick tog-force feedback.

Easing the throttle back to idle and slowingtowards the stall, the EuroFOX shows excellentmanners, with the clean stall arriving at 51mph,the stick back against the stop. Half ap saw thestall arrive at about 45mph which with the stickheld back was accompanied by a nodding andairframe buffet. Full ap and 45mph on the clockI was able to perform balanced turns in full controlwith ease; the stick back to stop gave an indicated42mph. Again the airframe talks to you by rst

Slow y-by with theaperons set at half ap

Easing the throttle back toidle and slowing towards the

stall, the EuroFOX showsexcellent manners

Gas strut holds the top hinged door well clear upunder the wing, making for an easy entry and exit

which is unhindered by the main gear


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DIMENSIONS Wingspan ...................................................29ft 10in/9.1mLength .............................................................18ft 4in/5.6mHeight ............ .............. .............. .............. ....... 7ft 4in/2.25m WEIGHTS & LOADINGSEmpty weight ............ .............. .............. ..... 636lb/289kggmauw .............................................................1,232lb/560kgUseful load .....................................................594lb/270kg PERFORMANCEMaximum speed ....................................143mph/124ktMaximum cruise speed (@4,600pm) ....................................................................................................110mph/95ktStall speed (without aps) ......................................33ktStall speed (with aps) ............................40mph/34ktFuel capacity ...................................................................86ltRange ............. .............. .............. .............. .............. ......... 620m

COST

From 43,500 inc VAT ENGINE

Rotax 912S or Rotax 912

SEATING2 CONTACT DETAILS www.eurofoxuk.co.uk

TECH SPECEuroFOX



buffeting, and if you really dont get the messageit starts to nod its head hopefully nally getting themessage across.

Armed with the stall speeds at our particularweight, I tried out a simulated poorly handledapproach which the aircraft took in its stride untilI stepped over the line by applying uncoordinatedcontrols and too little speed. The well-manneredEuroFOX tried to warn me by buffeting andnodding until nally relenting and dropping a wing,which was easily recovered. This aircraft tries itshardest to look after its occupants.

Reassured by the aircrafts handling, I explorecross-controlled ight, ending up with full aileronand rudder inputs. This results in very usable highdescent rates: 1,000fpm to the left and 1,300fpmto the right. Noting that the wind at 2,000ft isabout 30kt, I decided to abuse the EuroFOX a littleand carry out cross-controlled, wings-level turns.The EuroFOX excels at this.

Returning to the strip, we have a brisk 20ktwind just off the nose, which would make for ashort landing. I decline the offer of a crosswindlanding on the out-of-wind runway, but I feelcondent the aircraft would cope with windswell in excess of the published 17mph limit.With full ap and full aft trim, the EuroFOX settlesitself on nal at 60mph, happy even with handsand feet off. The landing proves very easy,requiring a reassuring last minute pull for apositive are. With no brakes applied, the coarseprop was still trying to pull us along even on grass,so I suspect brakes will be needed on smoothrunways for a short landing.

The EuroFOX is entering the affordable aircraftmarket place where I believe the competition willcontinue to grow. I think it will be in direct

competition with the other new boy on the block,the Trail both having two seats, folding wingsand in a similar price bracket. Presuming that theTrail will continue to be offered for 30,000,can the EuroFOX condently demand the12,500 over and above the Trail while offeringsimilar performance?

Despite the Trail and EuroFOX similarities, theyare a world apart in many respects. Of course, theTrail is all-metal and the EuroFOX is a moretraditional tube-and-fabric construction, but Ibelieve that they will appeal to differentcustomers. The Trail has a more rough-and-readyfeel about it, ready for an adventure. The EuroFOX,on the other hand, has an air of renement aboutit, undoubtedly driven by its most apparent asset,the quality of nish and build. This appeal isfurther enhanced by the fabric covering beingcarried out by the owner under supervision at thefactory. The aircraft is then painted by the factoryand shipped to the builder in two-three weeks.Although actually quite easy, the fabric coveringprocess puts many people off considering buyinga fabric aircraft. Ultimately the builder will have afactory-quality aircraft delivered to them thateffectively just needs assembling. This lifts a hugeresponsibility from the builder.

The EuroFOX has one trump card compared tothe Trail: wings folded, its 7ft 10.5in (well underthe recently-raised trailer limit of just over 8ft 4 in(2.55m), allowing it to be trailered home and putin the garage with ease.

The factorys determination to ensure that theirproduct will be of a very high build and nish,whether factory, LAA or BMAA built, will mean theEuroFOX is regarded as a quality product andquality will always sell.

Wings folded the EuroFOX is underthe UKs maximum allowable trailer

width. Neat simple wing-fold allowsfor major savings in hangarage or the

aircraft can be trailered home andstored in the garage

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