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Jet RookieBonding that canopy

Yak 130 from ready2flySmall version of Vitaly Robertus'

World Masters machine

A-4 SkyhawkSkymaster’s jet trainer

with a scale finish

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grate it into my Futaba radio control systemwithout a major investment in extra wiringand set-up time. The system is very unde-manding in respect of installation spaceand position, and features speed-depen-dent gain control when used in conjunctionwith a separate GPS sensor, which plugs in-to the unit. It also has one feature which isto the best of my knowledge unique: theiGyro works in two modes without manual

switching. The first is Normal or Dampingmode - the familiar mode present in everyother gyro - and the other is Headingmode.Heading mode is active as long as thesticks are at their centre position; when thepilot makes a deliberate control command,the gyro switches to Damping mode, andacts as a perfectly “normal” damping gyro,compensating for all movements not com-manded by the pilot. As soon as the pilotcentres the sticks again, the iGyro auto-matically reverts to Headingmode, i.e. with-out the pilot having to operate a switch.

iGyro in the EurosportNow let’s see the iGyro in practice: I in-

stalled the unit in my elderly Eurosport(second generation, detachable fin, large

fuselage hatch, JetCat P180 RX), in thehope of alleviating a couple of its badhabits: the well-known tendency to rockaround the roll axis to a greater or less ex-tent in windy conditions, and the tenden-cy to dip its nose in a turn.

PreparationBefore the gyro is installed in the model it

is as well to read through the clearly writtenand well illustrated manual, and the SetupAssistant instructions. The former iscompre-hensive, and covers all the unit’s featuresand functions in detail, while the foldedsheet covering the Setup Assistant is all you

need to set up the gyro in dou-ble-quick time. Before startingon the procedure, it is essentialto prepare two spare channelsat the transmitter: one three-po-sition switch for the flightmodes, and one slider or rotaryadjuster for gain control - forsafety’s sake please check

what you have assigned immediately usingthe transmitter’s servo monitor! When theset-up procedure is complete, the gain chan-nel can be disabled again, and used for anyother function.For the initial “dry run” I simply un-

screwed the appropriate componentsfrom the Eurosport and mounted them ona test board. This enabled me to playaround with the various configurations,and also gain a “live” idea of the servos’movements when the activated iGyro ismoved. Even so, I would recommend re-setting everything to zero before installingthe unit in a model, so that you really arestarting from “square one”; this is accom-plished by selecting Factory Reset in theiGyro’s menu.

Installing the iGyro in the EurosportThe installation procedure was unevent-

ful, as there were several possible locationsin the Eurosport which called for no majorstructural changes. The only requirementsregarding the gyro’s position are thatit should be perpendicular to the jet’svertical (yaw) and longitudinal (roll) axes,and ideally with a clear view of its integralscreen; the position you select is entered inthe menu at a later stage. The orientation ofthe gyro is defined by the position of thescreen and the Setup switch socket. Inmy case the screen is on top, and can beread off conveniently, while the socket for

the Setup switch faces left, towardsthe centre, where it is easily acces-sible. The switch is used to carryout the entire set-up procedure ofthe iGyro.The iGyro is supplied with self-ad-

hesive mounting pads, whichwould be destroyed every timeI removed the unit, so to avoid thisI mounted the device on a slightlyoversized plate made of a CFRPsandwich, and fixed this in the jetusing two screws. If there is nosuitable sub-structure for it, all youneed to do is glue two hardwoodrails in the fuselage to accept thegyro plate retaining screws. Thisarrangement makes it very straight-

forward to shift the unit from one model toanother.Once you have determined the gyro’s

location in the model, it takes about half anhour to complete the basic set-up proce-dure. At the flying site I would suggest thatyou spend a fewminutes activating the TestFly Assistant.

Set-upThe switch mentioned above is only

needed for the initial set-up procedure, andlater for any changes or fine-tuning re-quired. Alternatively you can leave it in themodel if you prefer. For maximum flexibilitymine has a permanent place in the pit-box,so I can make adjustments at any time.The switch housing is identical to that of

the Sensor-Switch and the switchessupplied with PowerBox battery backers. Ashort press on the Set button calls up themenu, and activates each menu point asrequired, while buttons I and II are used tochange the values.

Set-up procedureOf course, the fundamental requirement

is a model which has already been test-flown and trimmed accurately, with slop-free linkages installed at right-angles at theservo output arms and the control surfacehorns. The set-up procedure for the iGyrouses the Setup switch, and is very swift tocomplete: the Setup and Test Fly Assis-

JETPOWER 5/2014 4949

Test-rigprior tousing theiGyro in theEurosport.

And this is how the iGyrois installed in the Eurosport.

The picture on the left showsthe iGyro Setup switch as usedon the foam L-39.

when the landing is imminent - and thisdoes absolutely nothing for the pilot’snerves. Our flying site is often badly affect-ed by gusts, cross-winds and lee rotors,and those nasty moments on the landingapproach have already cost me manyEuros and probably a few years off my life.However, since I installed an iGyro, mymodel is distinctly smoother in the air, andall aspects of flight and landing have be-come substantially more relaxed. The jitterfactor - on the part of the pilot - has beeneliminated. A gyro may seem expensive -just on 400 Euro for the iGyro completewith GPS and USB - but the outlay is veryquickly returned with interest.I first installed the PowerBox Systems

iGyro in my small Sebart Katana, and I was

instantly hooked. In fact, it was hard to be-lieve that it was the same model. The ten-dency to wobble a wing in the harrier, ortuck under at full-throttle, were completelyeliminated, and the effect of the wind al-most completely disappeared! I subse-quently shifted the iGyro to my CARF Eu-rosport via the CARF Yak, and it has alsoshown its worth in my Hobby Top Gun L-39and CARF Ultraflash - the latter a jet, pleasenote, which actually does not need a gyro.More recently the unit has flown in a Eu-rosport Evolution with thrust vector control.I intend to report back on this later, togeth-er with my experience with the Ultraflash.In my opinion the iGyro is the most inter-

esting gyro system currently available: it islight and compact, and I was able to inte-

4848 JETPOWER 5/2014

GYROS IN MODEL JETS ERICH BÄCKERJPwww.jetpower-magazin.com

Jitter? My model doesn’t jitter! Okaythen, it’s not the model - but maybe thepilot is a little shaky. Anyway, our modelsare kicked around terribly by gusts of windor turbulence over the site and at the land-ing strip. And that’s exactly where fixed-wing gyros come into their own. In our carssuch automatic aids have long since beenstandard equipment - think of ABS and EPS- but many jet pilots still shy away fromthem. And which of us wants it said of himthat he can’t manage his model without thesupport of electronic gizmos?For normal flying in optimum wind and

weather conditions there is absolutely noneed for a gyro. But if the wind is gusty, orchangeable in direction, jets can easilydevelop a mind of their own - especially

Do you still havethe jitters,

or has a gyrocalmed

you down?

ThefromPowerBox Systems inmodel jets

The Eurosport was one ofthe test candidates.

speeds by changing the speed factor. The3D GPS sensor constantly monitors the air-craft’s speed, and increases or reduces thegyro’s gain accordingly. The gyro stores therecorded Vmax, and adjusts the gain ap-propriately. Increasing the speed factor byone increment causes a more rapid reduc-tion in gyro gain as airspeed rises; this en-sures that the jet remains sensitive at land-ing time, but eliminates the tendency to os-cillate at high speeds, without reducing thegain value. As an example, flying my Eu-rofighter I selected these values during theset-up flight: aileron 28 / 14%, elevator 50 /25% and rudder 90 / 75% (in each case forNormal / Heading mode). During the fine-tuning procedure I then increased thespeed factor to 4 on ailerons only, i.e. at lowspeeds I can set higher gain, and the gaindeclines more rapidly with increasing air-speed - result: 30 / 19%.The canards are assigned to the second

elevator channel, and for this function I setup the values manually. This is accom-plished simply by assigning a slider or ro-tary knob channel to gain control for thatspecific gyro output, and increasing gyrogain during a test- flight. For the canardsthe values I obtained were 95 / 80% for Nor-mal / Heading mode. At present I only haveiGyro support on the canards in FlightMode 3, which I use for low-speed aerobat-ic manoeuvres.

Heading Mode in the iGyroAs already mentioned at the start, the

iGyro operates in Normal (damping) modeunless the sticks are at the centre position,when it switches to Heading mode (withmodel helicopters this mode used to beknown as Heading Lock). Flying in Heading

mode is different from Normal mode; thejet appears to fly on invisible rails, and thisdoes require a certain amount of familiari-sation. But it does not mean that the modelis completely different to fly; it just has to beflownmore actively. Any tendency the mod-el used to have to correct itself are nolonger present. For example, if the jet usedto pull out from a loop or a reversal by itself,then it will no longer do that in Headingmode! However, once you have becomeused to this behaviour, you will soon learnto love it!If you do not immediately feel at home

with Heading mode, you can disable it inSetup. An alternative ploy is to define oneflight mode with Heading mode, and onewithout (see Flight Modes). With the Head-ing function active, the iGyro attempts tomaintain the jet’s current flight attitude. Asthe model’s speed declines, this has differ-ent effects depending on the specific air-craft: for example, the Eurosport losesheight safely and controllably, i.e. the iGyroretains and amplifies the typical delta low-speed characteristics. Non-deltas have areduced tendency to tip-stall, so they canbe flownmuchmore slowly and then simplylose height straight ahead. However, theiGyro’s Headingmode does not take thingsso far that it allows the model to slow downto the point of stalling; this means that thegyro can be left active on landing and take-off without any danger.If the pilot has a sensitive “throttle foot”

and a turbine which responds quickly, it ispossible to control the landing and themodel’s speed by adjusting its angle of at-tack. In broad terms, with the iGyro I findthat I only have to align the jet with the run-way, set up the correct approach angle and

leave the sticks alone … this initially calls fora mixture of courage and faith in the expe-rienced jet pilot. Of course, if you are al-ready reasonably familiar with your ma-chine, it is better to make the correct re-sponse before things become risky -especially if the turbine’s throttle responseis relatively slow!

Trim function and Heading ModeThe moment you adjust the trim associ-

ated with one of the axes to which the gyrois assigned, the Heading function is dis-abled until the iGyro is next switched on;the gyro perceives the deviation from thezero position as a control command, andtherefore continues to operate as a stan-dard gyro in Normal mode. Every time theiGyro is switched off and on again, the unitadopts the new servo positions as its refer-ence neutral settings.

The flight modes in the EurosportFM 1: gyro completely off, signals are

looped through 1 : 1; in my case FM 1 is theup / out position, but this is just a matter ofpersonal preference.FM 2: Normal mode for all three axes,

Heading mode for aileron and elevator;Heading mode on rudder makes no sensehere, otherwise the gyro compensates forturns with the rudder, causing the jet to“hang” in the turn (see above for values).FM 3: Normal mode for all three axes in-

cluding canards, Headingmode for aileron,elevator, rudder and canards (for aerobaticmanoeuvres and low-speed 3D manoeu-vres). The gain values are quite high in FM3; values: aileron 60 / 30%, elevator 60 /30%, rudder 100 / 80%, canards 95 / 80%,in each case for Normal / Heading. With

JETPOWER 5/2014 5151

The “foa-mie” L-39fitted witha JetCatP20 turbi-ne; theitem inthe fore-ground isthe Setupswitch.

tants guide you all the way, and the integralscreen informs you what has to be done; ifyou need additional information, that isavailable in the supplementary instruc-tions. The Setup Assistant enables the gy-ro to learn the control channels you have al-ready assigned at the transmitter, and thetwo auxiliary channels for the flight modes(FM) and gain control. All you have to do isselect the appropriate menu point andmove the corresponding sticks or adjustersat the transmitter - job done!One crucial aspect of the procedure is to

set the correct directions of effect of theiGyro, and to check them extremely care-fully; i.e. the gyro must be set to compen-sate for uncontrolled movements, and notto amplify them further; get this wrong, andthe consequence will invariably be the totalloss of your model. There is a simple rulewhich will avoid tying your brain in knotsover this: the gyro must always deflect inthe direction of the movement: if the tailmoves up - the elevator must move up; leftwingtip up - left aileron up, etc.Once the basic settings have been en-

tered in the “Basic Setup Assistant”, thenext step is to activate the Test Fly Assis-tant in the iGyro’s menu, and move allthe sticks (aileron / elevator / rudder)briefly to their end-points. The gyro now“knows” the travels, and you’re ready tofly the model!After take-off the pilot flies the aircraft

at moderate speed, and, with the gyro ac-tive (Flight Mode 2), slowly raise theaileron gain using the appropriate slideror rotary knob until a slight tendency tooscillate becomes apparent. Now reducethe adjuster’s setting a little, fly a few cir-cuits at varying speeds and perhapsmove the sticks around quickly to try and

provoke oscillation (this works quite wellwith the rudder), and - if necessary - ad-just the gain slightly to suit. The pilot nowswitches to the elevator setting and re-peats the procedure. After this comes therudder gain, and as a final step ruddergain specifically for the Heading range forany 3D manoeuvres you have in mind.And that’s it for the moment!Just one flight is all it takes to set up all

the primary axes individually! This set-upprocedure is sufficient for 95% of all mod-els, eliminates the influence of the wind,and also damps down many an unwantedcharacteristic of some models; in so doingit definitely reduces the tendency for the pi-lot’s knees to knock.Anyone who is not confident about the

set-up flight - and that could well mean vir-tually every pilot - should simply ask a col-league to operate the switch and the sliderfor him. In this case your assistant wouldhave to be instructed in the procedure, andperhaps also work his way through the Set-up Assistant on a “dry run”. If your col-league keeps the step-by-step diagramfrom the supplementary iGyro instructionsin his hand, there is really nothing thatcould go wrong.

GPS speed sensorSo what has airspeed to do with the gy-

ro? Plenty! If test-flown at moderate speed,the iGyro carries out its corrective actionswith the appropriate gain, i.e. with controlsurface deflections suitable for moderatespeed. However, at low speed larger travelsare necessary, while high-speed flight re-quires only very minimal corrections. Inbrief, a gyro without a speed signal wouldneed to be set up for reduced gain at highspeeds, otherwise oscillation could occur.However, this would reduce the gyro’s ef-fectiveness at low speed (landing), whichequates to forfeiting a major part of the de-vice’s potential benefits.The iGyro employs a very accurate 3D

GPS sensor for measuring the model’sspeed. This sensor features a special aeri-al which provides accurate speed mea-surement even in a vertical climb or invert-ed flight. Incidentally, the sensor can alsobe used on its ownwith virtually any teleme-try-capable 2.4 GHz system.

Fine tuningFor models with a relatively wide speed

range it may be necessary to suppress aslight tendency to oscillate at fairly high

5050

Calibrating theaileron function.

Screen-shotof the iGyro’sAssistantdisplay.

The model’smaximum air-speed can be

read out atany time; thisshot shows

the Eurosport.

Once the basic settings havebeen entered in the “Basic SetupAssistant”, the next step is to activatethe Test Fly Assistant in the iGyro’smenu, and move all the sticks brieflyto their end-points. The gyro now“knows” the travels, and you’reready to fly the model!

these settings it is possible to fly terrifichigh-alpha manoeuvres, great flips andsometimes even flat spins “on the spot” -without thrust vector control!Important: FM 3, with its increased gain

values, can only be activated in low-speedflight. As soon as the Eurosport picks upmore speed, I have to switch back to FM 2- otherwise the model starts oscillating!Note 1: for my propeller aircraft I set all

axes to 100% in FM 3 for Normal and Head-ing modes. If I let go of the sticks and justcontrol the throttle, torque-rolling is child’splay, and needs no input from me at all.Note 2: if you wish to feel your way slow-

ly towards Heading mode, it is a good ideato enter the set-up values you have alreadydefined as the starting point, and in FM 2simply set the Heading values to 0% usingthe Setup switch, i.e. Normal mode only forFM 2; the jet now flies simply with gyro sup-

port. For FM 3 you should activate thepreviously defined Heading values,but without Heading on rudder. Thisarrangement temporarily eliminatesaerobatic mode, but allows you tofeel your way towards Heading modeslowly, and make direct compar-isons.Note 3: in the latest version of the

iGyro’s software all three flightmodes can be assigned set-up val-ues, for example: FM 1 - low gain inNormal mode without Heading, FM 2- previously defined settings with Nor-mal and Heading, and FM 3 - 3D oraerobatics, with rolling manoeuvresas straight as a die.

Summary: the EurosportThe Eurosport now appears to be

an entirely different jet to fly. Theaeroplane is less twitchy, and fliesmore smoothly; in simple terms it isjust more “jet-like”. Landings, espe-cially in windy conditions, are just asstraightforward as without wind. Myexperiences are more than positive,and for this reason the iGyro is per-manently installed in the Eurosport,which now features “scale-like” gyro

effects (as we all know, the full-size Eu-rofighter flies with total gyro support).

iGyro in the L-39Anyone who is familiar with the Hobby

TopGun L-39 will immediately start thinkingabout a gyro. Not that this aeroplane actu-ally needs such a thing; the foamie jet fliesstraight and precisely, and lands as soft asbutter in calm conditions.The iGyro ended up in this machine be-

cause I lacked a suitable receiver, but hasstayed there ever since, as the combinationhas proved outstandingly effective! The on-ly receiver I had spare was a Futaba R7008,and its eight channels were too few. How-ever, in combination with the iGyro it is pos-sible to exploit eighteen channels: bothailerons, the elevators and the rudder areconnected directly to the iGyro, which inturns receives its signals in serial form via

the S-Bus from the receiver, to which throt-tle, retracts, turbine, turbine aux, nose-wheel steering and lighting are directly con-nected - and it works! Wiring arrangementsfor this type of application are included inschematic form in the iGyro instructions.Fully fuelled, the foam jet weighs just on

3.5 kg, which means that it is naturally sus-ceptible to wind: in straight flight in windyconditions it manifests a slight tendency torock around all axes, and on the landing ap-proach the little model is terribly buffetedby gusts and cross-winds.I carriedout the set-up flight, and the result

was fantastic, as were subsequent flights: asmooth-flying model even in quite strongwinds, accurate rolls without any need formixers, and inverted flight without the needfor ‘down’. On the landing approach thefoamie carves through the lee rotors withoutany problem. Finally the L-39 no longerdrops a wing if I have to rip it off the groundafter a fairly long take-off run on long grass.The most impressive aspect is this: in gustyconditions even quite large non-gyro aircrafthave to stay on the ground. With the iGyro, Ican relax and carry on flying.

One final tipA large number of jet pilots set up their

models with very high Expo settings onaileron, elevator and rudder. However,since the gyro does its most pronouncedcorrective work when the sticks are at theneutral position, and its effects are onlysuppressed substantially as the sticks aredeflected, many pilots find their aircraft re-spond in a spongy way, i.e. less directly, af-ter the set-up procedure. I counter this bysetting up a second flight mode with about15 to 20% less Expo, and use the iGyro’sflight mode switch to select it - it works!

SummaryFor my purposes the iGyro has become

an important part of the safety equipmentof my jets, and it has already savedme fromlanding damage several times. Since myfirst experiments I have installed iGyros inmy three active jets and even my 3D pro-peller machine, and I am not inclined to re-move them again! The models fly and landmuch more smoothly, and I as pilot alsobenefit from this - everything has becomesmoother, and the jitter has disappeared. Asuccessful experiment, to my mind!

JP

JETPOWER 5/2014

And that’s allthere is to it. Atthe end of theprocedure the

iGyro hopes you“Have fun”!

For my purposes the iGyro has become an important partof the safety equipment of my jets, and it has already saved me fromlanding damage several times.

5252

EXEMPLIFICATIONsetup for the L-39