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The trike unit is made by Eurofly, based innorth-east Italy. Grif, who build the wing,have been producing hang glider andultralight flexwings, mostly for the Italianmarket, from their base near Rome since1989. Combinations of the Snake unit withvarious wings, props and engines areimported by Airplay Aircraft. Owner DavidBroom is the current flexwing microlightWorld Air Games champion and runs amicrolight training school out of SuttonMeadows. A highly experienced pilot andinstructor, David’s background includesparagliding, Doodlebugs and a stronginterest in the lightweight end ofmicrolighting. He has had an active role inthe design and testing of the Snake and itssuitability for the UK.

I had been asked to review the newmachine as our aerotow club operates fromthe same airfield, and due to my hangglider pilot’s interest in it. Despite recentlygaining microlight and tug pilot licences, Istill consider myself primarily a hangie.The setup I flew was the Snake trikemarried to a Grif 3DC wing, powered by a

27hp Cisco C-Max two-stroke engine andwooden prop with a recoil hand starter.

The Grif 3DC Nanoflight is a 13.5m2

kingposted, concealed cross-boom, 65%double surface wing weighing 28kg. It has atotal of 13 top surface and four lowerbattens. The tips on the latter hide snuglyinto little pockets in the wing undersurfacewhile the top battens are retained byelastic. All the top wires connect to the topof the kingpost, the luff lines connecting tothe sail at the 3rd and 5th battens. The A-frame has aerofoil aluminium uprights anda round, straight base-bar withconventional knuckles for side-wireconnection. The sail material is Dacron,with a PX20 trilaminate leading edge as anoption. A row of small plastic vortexgenerators along the leading edge helps thestall characteristics. The wingtips can betuned by loosening two screws and turningthe plastic tip-plate.

The trike unit was built with the Grif 3DC inmind but can take other wings such as theFox 13T. Although the UK does not legallyrequire certification, the Snake/Grif

combination has been in-house tested toDULV standards, and to +6G with a 100kgpilot with no deformation.

The frame construction is of double 6082 T6alloy tubing, with twin Ergal 7075 25mmdiameter undercarriage legs. The maintubing connection points are pre-paintedsteel brackets (colour options are available).The undercarriage legs look lightweight butare successfully used on aircraft weighingthree times as much. The front wheel, withdrum brake, attaches to a steel bracket on afriction-adjustable pivot.

The top section of the mast, angledforward slightly, is joined to the lower partby a steel bracket. The wheels arelightweight spoked plastic with foam-filledrubber tyres – no worries aboutpunctures. The trike unit without enginefeels incredibly light – I could easily pickit up with one hand. The undercarriagelegs can be detached for transport byremoving a single retaining pin on eachleg. All fittings and connections combinerobustness with simplicity, satisfying tosee in this level of wing.

Airplay Snake CHARLIE RICHARDSON REPORTS

The Snake is a new contender in the recently established sub-70kg class (see Steve Uzochukwu’s description inthe November 2017 issue). From a foot-launched glider pilot’s perspective the main differences are that you havewheels, you are seated and you have an engine.

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RiggingRigging the wing, flat or on the A-frameusing a keel extension, is quick – about eightminutes – and straightforward for anyonefamiliar with rigging a hang glider. Thelower front wires attach using a swan-neckcatch before the nose cone is fitted. The

conventional cross-tube tensioning cablehooks onto a pylon on the keel and the toprear wire connects to this with a shackleand pip-pin. The wing stows into a normalhang glider bag for transportation or storage.The fully-derigged length of 5.32m can bebroken down to 4.58m, or 3.57m if required,using simple push pins on the leading edge.

To rig the trike, removal of a single bolt,butterfly nut and split ring at the bottom ofthe mast allows it to pivot forward. The

whole unit is then simply rolled forwardbeneath the rear of the nose-down riggedwing and over the base-bar. The mastattaches to the wing with a conventionalmetal hang bracket around a nylon blockon the wing’s keel, and a hang bolt with abutterfly nut and split-ring. The hangbracket position in front of the A-frame canbe adjusted along the keel by moving sixnylon spacers; for the test flights it wasfixed in the second from rear position.

The trike rolls back as the wing’s nose israised. At this point a set of rear-wheelchocks helps keep the trike stationary whilewing and mast are lifted, until the mast isupright and its retaining bolt can be refittedinto the bottom bracket. The front strut thenfits between the top of the mast and thefront bracket of the frame, both endssecured with pip-pins. The final step is toattach the fuel tank. De-rigging is the reverseof the above; Dave was able to achieve thisin five minutes, talking all the while.

Engine and propBoth the 175cc Cisco C-Max (27hp) and theoptional 230cc Bull Max (33hp) have internalbalance shafts to smooth operation. Electricstart, generator, forced-air cooling andcentrifugal clutch options were not fitted onthe sub-70kg demonstrator to minimiseweight. Both engines have the option of theCisco wooden prop, used for the test flight, or

a Helix carbon-fibre one. The formerreportedly gives slightly more thrust and asmoother sound, the latter is more hard-wearing and can be folded in half whenremoved – useful when transporting by car.Cisco engines are used with paramotors andhave an established UK agent, Skydrive, witha good reputation in the microlight world.

The engine brackets attach to the mast justbehind the seat and the manual start cableruns up to a handle above the pilot’s right

shoulder. The ignition switch is below thefront of the seat. The petrol tank attachesbehind the seat, held firmly in place bybungees with a quick release for the fuelpipe. The fuel on/off switch is an easy reach-down on the left side. Fuel is unleaded, pre-mixed at 33:1. With an average consumptionof under 4l/h, a full 10-litre tank should giveover 2.5 hours if taken to the limit.

ComfortAlloy tubes top and bottom support anadjustable Cordura hammock seat withfour-point safety belt. This was socomfortable and pressure-point free thatonce flying I forgot about it completely. Theflying position felt nicely relaxed with myknees an inch clear below the base-bar (I’m6ft with shoes), and my feet resting on heeland foot supports either side of the frontwheel, throttle pedal under my right toeand brake under my left.

The reasonably upright head and armposition was natural, with no straining ofneck or shoulder muscles and hands easilyresting on the base-bar. To push the barfully forward to the front strut requiredbending forward slightly, but this is a rareevent in flight except when testing forstalls. Normal in-flight manoeuvres did notrequire any body movement. Whilechecking the limits of wing movement onthe ground the base-bar touched my knees

when fully banking the wing – a radicalamount of movement you don’t need innormal flight, easily solved by moving myknees to the side.

InstrumentsA mini-USB charged Fly ElectronicsMotoMonitor wirelessed the engine RPM,exhaust gas temperature and cylinder headtemperature to a display unit between mylegs on the Snake frame. The first two are

Hang bracket – note adjustable spacers

Conventional cross-tube tensioner Rear frame and bungee-secured fuel tank

Optional PX20 leading edge and neat vortex generators

Snake unit ready to receive wing ... or to go in the back of anestate car

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recommended as the minimum needed to monitor the engine.Other options such as a fuel gauge sender are also available. Thedisplay unit also gave GPS-based ground speed and alti/vario data,and had a ‘get you home’ function if lost … which of course BHPApilots never are!

In the air‘It’s just like flying a modern hang glider’ were my first words onlanding. An obvious statement in some ways, as it is of course ‘just’a hang glider with some wheels and an engine, but I meant it wasso easy to tune in to and to fly. The way it behaved was just like agood intermediate hang glider wing and I immediately felt at homewith it.

The test flights were on a sunny December day with 5 degrees airtemp. and a 5mph 40-degree crosswind on the perfectly dry(despite weeks of rain and snow) Sutton Meadows grass runway.1,000ft winds were about 15mph, increasing through the afternoon.My fully-kitted weight is about 87kg. My hangie instruments wereattached as a check on the Snake’s GPS instruments.

The engine was on ‘running-in’ carburettor settings but Davidassured me it was fine for holding full power at around 7,800rpm.The engine was already warm from earlier runs so I didn’t get todo a cold start, but the warm start was easy. A single over-the-right-shoulder pull forward on the starter cord and it fired firsttime, and kept going with a little bit of throttle until it settled downafter a few seconds and could be left at tickover. Taxiing and doingground-based checks while the engine CHT heated up to 120degrees C, I was happily surprised at how light and easy the wingwas to move around – imagine swinging your hang glider aroundwhen its weight is being supported for you. Much easier than themicrolight wings I’ve got used to.

Engine pickup to full power was immediate, the take-off run was

under 50m and the lift-off was smooth and undramatic. The wingimmediately felt light, sensitive and controllable. In the initial 200ftI caused a bit of pilot-induced yaw – my rigid-wing hang glider/XLtug flying experience had made my muscle-memory forget how tofly a lighter and more sensitive flexwing. Relaxing, applying justfinger-tip pressure to the base-bar and not overcorrecting, got ridof the yaw as I climbed through 500ft. Letting go of the barcompletely did an even better job!

The engine/prop noise behind me was smooth and at a lowerpitch than I was expecting. Continuing to climb on full power upto 2,000ft at 540fpm and starting gentle turns, I was fascinatedby how light and sensitive the wing felt compared to otherflexwing microlights I’ve flown. It flies like a hang glider, d’oh!

Levelling off at 2,000ft I tried steeper turns. A lateral movement ofaround 3-4cm put the wing into a 30 degree bank in two to threeseconds. Pushing out after initiating the roll made it roll slightlyfaster and turn more rapidly. Reversing the turn was simple andquick – there was no fight back from the wing. Letting go of thebase-bar while banked at 30 degrees, the wing gently came out ofthe turn; after two 360s it was banked at about 15 degrees. Thiswas the same in both directions. Banking to 45 degrees wassimilarly quick and light with very little bar pressure required,and again the wing settled into the bank with a slight tendencyto straighten up. With confidence growing I took it to my personalmaximum bank of 60 degrees, and again it was light andresponsive. Holding this bank I flew through my own waketurbulence and the wing allowed me to ‘feel’ the waves ofturbulence. The amount of feedback was excellent and on a parwith any hang glider I’ve flown.

Confidence high, I tried to stall the wing using the standardmicrolight stall check: reducing airspeed at around 1mph/secwith the engine at tickover. The bar pressure gently increased asI pushed forward until the bar was touching the front strut, but

it would not stall! At a corrected indicated airspeed of under23mph the wing was slightly mushy, but I still had lateralcontrol and I could not go any slower. Approaching the stallmore rapidly the wing slowed down more and I finally felt thenose nod briefly, then pick up again. Total loss of height wasaround 10ft. Not bad!

Back to hands-off trim while maintaining height, the airspeedsettled at around 33mph. Trying the other end of the speedrange, the bar pressure gently increased as I pulled in from trimbut I could hold it fully against my chest without difficulty,settling at around 50mph with a little pilot-induced yaw until Ismoothed it out. I could get the wing to briefly go slightly fasterby rapidly pulling in, but it then settled back to 50mph.

At tickover the sink rate at 33mph trim was about 160fpm, andslowing down below trim did not improve this. At 45mph it was300fpm, at 50mph 400fpm – pretty good. Although tickover is notquite the same as engine-off, the sink rate is in the range whereit should be possible to thermal. The wing is definitely responsive,yet stable enough that it should be easy to thermal withconfidence. On approaching the field I hit strong wind-shearturbulence at 400ft, and after the initial surprise I tried playingaround in this section of air. The wing felt safe and sensitive,giving great feedback and never any concern that it was about toget nasty.

The powered approach crosswind landing was easy to managewith a short hold-off as the wing slowed down. I hit the spot Iwas aiming for, the back wheels gently touching the groundwhile waiting for the front wheel to touch. Deceleration on thegrass was then smooth without using the brake, just gentlyturning to avoid a molehill before stopping!

In summary, the Snake/Grif setup will feel natural toexperienced hang glider or micro pilots. At times I forgot that Ihad an engine and just enjoyed the wing. It handles like a good

top-end intermediate hang glider: it feels safe, has a good sinkrate and glide, and the light and sensitive handling that youneed to be able to thermal, or just play, with ease. Microlightpilots may be surprised by the good glide angle at speed, andhence the inability to lose altitude by pulling in on approach,but this should not be a problem for hangies.

Although no licence is required, you need the skills to use powerand wheels. David is providing a time-limited offer of up to fivehours microlight training as part of the roughly £9,000 package.Less-experienced pilots may prefer the Snake with the slower,lighter Fox 13T wing (see November’s PeaBee write-up). This, plusthe Bull Max engine, would be better for small fields due to thehigher climb rate and steeper landing approach.

The Snake/Grif would be great to fly on days when you can’tget out hang or paragliding, midweek when others aren’taround for aerotowing or winching, or only have limited timeto spare and somewhere legal and close for take-off andlanding. The ease of storing at home, transporting and riggingis almost as good as a hang glider. Anyone who finds it hardwork foot launching a powered hang glider or paraglidershould also take a look. The Snake is an excellent addition tothe exciting new sub-70kg class.

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Specification

Model Snake/Grif 3DC

Sail area (m2) 13.5

Span (m) 9.4

Aspect ratio 6.55:1

Packed length (m) 5.32m

Short-packed length (m) 4.58 or 3.57

% double surface 65

No. of battens 17

Trike material 6082 T6 aluminium, chromoly steel

Airframe material Avional 2017A

Powerplant Cisco C-Max 175cc

Power output 27hp

Fuel capacity (l) 10

Empty weight (kg) 62kg

Max. take-off weight (kg) 158kg*

Max pilot weight (kg) 100kg

Certification None; meets DULV standards and +6g load test

Price (inc. VAT)* £9,183**

Importer: Airplay Aircraft Ltd, Sutton Meadows Airfield, SuttonGault, Ely, Cambs CB6 2BJ,

tel: 07773 253454, e-mail: info@airplayaircraft.co.uk, website:www.airplayaircraft.co.uk.

* 2018 version now tested to +6/-3G with a MTOW of 190kg

** Test aircraft, with PX20 leading edge and vortex-generator options: £9,498.

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