25-Jun-24 - 05:48 PM

Thermal Circle Text - Thermal Circle 23

Written by Hayden Daley - 01 February, 2012.

Welcome to this edition of the Thermal Circle in this edition is the Hi Tec Aurora 9 review by Dean Williams and also the HI Tec 2.4ghz telemetry review, a review of the DFS Habicht by Danny Malcman and finally a review of the Fly Dream2 .4 Ghz Radio Gear by Hutton Oddy
All information is reproduced with permission from Model Engines, minor editing and changes to the text by Hayden Daley January 2012.
Available from

HiTec Aurora 9
by Dean Williams

For Hitec fans wanting to upgrade to a transmitter with more memory, more channels, more features plus the benefits that 2.4 GHz has to offer, the wait is finally over. The newAurora 9 delivers 9 channels, 30 model memories, and functionality to operate a diverse range of powered fixed-wing aircraft, gliders and helicopters Hitec have used the extra development time well, listening to users and learning from the mistakes and triumphs of their competitors to incorporate extra technology not seen on products in the same class released ahead of it.

So what’s it all about? The review package is the Standard set and features the Spectra 2.4 GHz module, Optima 9, nine channel receiver, 4, HS-5485HB digital standard servos , 45g with 5.2 kg/cm torque at 4.8 volts and hardware. A 1,300 mAh transmitter (6-cell) and receiver (4-cell) NiMH packs, charger, heavy duty switch harness, foam wrapping for the receiver and a screen cleaner/stylus. The 132 page instruction manual is clearly written and well laid out with handy notes, tips, caution and warning panels sprinkled throughout. It covers the essentials including, setting up and operating the TX and RX and examples of programming for a basic plane, glider and heli functions and also goes into some of the more commonly used mix programming. There are two other Aurora 9 packages available, the “Basic” package which is just the transmitter, 2.4 GHz module ,transmitter battery and Optima 9 receiver and the “Premium” pack­age which is the same as the “Standard” package except the 4 servos included are the higher spec HS-7965MG digital servos, 62g with 8 kg torque at 4.8 volts. .

In the hand the radio is fairly conventional in form, the TX is easy on the eye and the red highlights on the ends of the sticks add a bit of bling without going over the top. The shape and feel of the wrap around soft rubberized grips lets you get a confident hold and at 940 g, you will notice the weight if stepping up from a basic 4-or 6-channel unit but its at the lower end of the weight range when compared to others in the 8+ channel fraternity. The eyelet for the neck strap is located just above the sliding power switch, such that the unit will hang antenna up at about 45 degrees, but if you prefer a different angle to the dangle, then there are plenty of after­market neck-strap adapters around if you intend using that function for extra support.

The crowns of the adjustable length sticks fall nicely under the thumbs and provide good grip, though some may find them a little sharp. The movement of the sticks is ultra smooth, thanks to twin ball races on all four axis. All trims are digital and located in the lower positions of the gimbals. The two rotary sliders on either side of the case are easily operated by the index fingers, these sliders have about 40 notches in the full sweep of about 60 degrees, but lack a more pronounced notch locating mid sweep, preferred by some, though the unit does beep when the sliders pass through centre. There are plans to add the notch in future production runs .The switch clusters are nicely spaced with the placement of long and shorts switches working well. Three of the 4 switches on the upper left of the unit are 2-position with the remaining switch 3-position, and there is a second 3-position switch on the upper right of the case, accompanied by a pair of 2-position switches and a spring loaded switch.

All switches are allocated a unique letter, from A-H because they all have user assignable functions, so rather than having 3 switches that are dedicated to switching dual rates for elevator, rudder and aileron, any, or no switches for that matter can be assigned as dual rate switches. This flexibility of functionality has been a feature of European radios, dare I say it’s very Multiplex like for many years and is finding increasing favour in Asian radios. There are also 3 assignable trim levers on the upper face for fine tuning preset mixes on the fly. The mounting of these supplementary trims felt a bit soft and they can move quite a bit before registering. Dominating the lower front face is the 127 x 37 mm backlit monochrome (black/green) LCD touch screen. Touch screens were once the domain of only the highest spec radios, but as they are becoming prevalent in our culture through I Phones, PDA’s and GPS’s, its little wonder they are beginning to become more common in our hobby. The screen resolution is 320 x 80 and the text and pictures may seem a little grainy but certainly clear enough and you usually get the selection you want just using your finger tip. However for greater precision, there is a type of stylus included and this also functions as a screen cleaner. The screen is also fitted with a protector. Being an electric flyer, I only have to worry about dust, sweat and sunscreen on the display which didn’t worry it and I imagine it will hold up just as well to fuel. An advantage of the touch screen is that there are no buttons/rollers to gum/ grime up.

Flipping the Aurora 9 over, the two main features are the removable Spectra 2.4 GHz module and the battery cover. The Spectra module is well recessed into the back of the Aurora 9, not even the small housing where the thin coaxial wire exits the module to connect with the antenna, protrudes beyond the rear face, so you don’t have to think twice about laying it on the bench or ground. The antenna wire has very little slack in it so it hugs the contours of the case. The module is held in with a pair of clips and is a very snug fit, taking a bit of careful effort to release. The module also has a covered socket to plugin the cable for theHPP-22 PC interface.

Under the battery cover is a flat 6-cell 1300 mAh NiMH pack, that contributes to the units relative light weight and with the Aurora 9’s current draw of 300 mAh transmitting and backlight on, it should be good for about 4 hours of run time. Using 6 Ni cells with a nominal voltage of 7.2 volts means the unit will also happily operate on an unregulated 2S pack of LiPo cells, nominally 7.4volts, providing longer run times between charges. To suit the different battery types, the Aurora 9 has programmable power management functions and low voltage alarms. Whilst, the charge socket uses the same plug type and polarity as regular Hitec radios, if a LiPo pack is used to power the Aurora 9, it must be charged with an appropriate LiPo charger, preferably out of the transmitter.

Operating at 7.2 –7.4 volts puts the Aurora 9 at odds with most other Hitec sets that operate on 9.6volts (8 Ni cells) and this means a special buddy cord system is needed to connect the Aurora 9 with these 8-cell radios. To enforce this, the socket for the buddy cord plug is in the back of the Aurora is a 1/8inch stereo jack, a change for Hitec from the old 6-pinDIN plug. A major feature is that you no longer need to open up the case to change stick modes. There are small rubber plugs and removable rubber grips on the back of the case and these cover holes that provide access to change the gimbals mechanics spring and ratchet tensions using a small Philips head screwdriver. Up top, the handle is nice and large and the stubby 2.4 GHz antenna clips into a removable holder so it can be readily swapped for a 36 Mhz telescopic antenna when the new Spectra Pro module becomes available later this year. The antenna can rotate 360 degrees and can be bent through 90 degrees with a notch at about 45de­grees.The wiring in mine was a bit stiff and it rested more like 87 degrees.

There are two camps that RC spread spectrum 2.4 GHz systems seem to be splitting into, fixed frequency and frequency hopping. Aurora 9 is in the frequency hopping camp, with its Adaptive Frequency Hopping Spread Spectrum(AFHSS) system also common to the other Hitec 2.4 GHz systems where it hops across 20 of the 79 channels allocated in the2.4 GHz band, only staying on a frequency for1/250th of a second. But wait there’s more. Two different frequency hopping modes are available, Normal mode and Scan mode. In Normal, the 20 channels are locked in when the receiver is bound to the transmitter, and these are used each time the TX is switched on. In Scan mode it scans the spectrum and chooses the 20 cleanest frequencies to operate on and this is where the Adaptive bit comes in. Later, if you swap from Scan mode to Normal mode, it keeps the Scan mode frequencies. In Normal mode, the receiver recovers the connection very quickly from a power black-out and two or more receivers can be operated in tandem for redundancy. There is a chance that in the cycle of hopping, it could hop onto one or more “dirty” channels, particularly in a heavy 2.4GHz environment, degrading signal quality. In Scan mode you get the best chance at clean signal quality but only one RX can be operated at a time and I found it won’t recover the connection after a power black-out at either end. Both modes have their advantages and disadvantages and rather than arbitrarily picking one system Hitec have given us both letting us to make the decision which is the best for our situation.

2.4 GHz receivers available to accompany the Aurora 9.The Optima 9, Optima7 and Optima 6 which if you haven’t worked it out by now are 9, 7 and 6 channel respectively, The 9,7 and 6 weigh 22, 17 and 15 grams respectively, comparable in weight to equivalently channeled modern 36 MHz receivers, the Optima 9 has 2 antennas, adding a few extra grams. The antennas are where Hitec have chosen to tread their own path. Boosted Omni­ Directional Antennas (BODA) is their design which enhances sensitivity and signals weakened by distance or obstructions can still be correctly perceived. So much so that Hitec believe a single BODA antenna provides sufficient reception for most applications. The second antenna on the Optima 9 is there for a belt and braces approach for more peace of mind in more challenging applications. The antennas plug into the circuit board using a UFL micro coaxial plug so they can be easily replaced if damaged, or with one without the boosting sleeves to make them more compact and light. If looking for something even lighter a small 4channel Optima for indoor use is in the pipeline.

Carbon fibre fuselages can be a challenge for 2.4GHz systems as the material can block the radio waves. To overcome this it is only necessary to have the thin antenna wire (the whisker) protruding outside the fuselage banishing the brownouts. Brownouts were a problem that sprung up early in the adoption of 2.4 GHz gear, where the receiver would re-boot if the supply voltage momentarily dipped below a critical level. A voltage dip could be caused by a stalled retract servo, high momentary loads on all the servos at once such as in extreme maneuvering or an overtaxed BEC. The reboot could take a few seconds during which time the receiver was off-air, sometimes forcing the aircraft out of the air, not good! To remedy this, manufactures have developed faster reboot times and/or resorted to capacitors to prop up voltage dips. The minimum operating voltage for the Optima receivers is 3.5 volts but its recommend to keep the supply above 4.5 volts as Hitec’s approach to minimize the risk of brownouts.

Power of up to 35 volts from a dedicated supply can be fed in to the receiver to support the functions of the receiver only. This power is not fed through to the servos, they still need to be powered from the regular power supply, a 4-or5-cell NiMH pack or the BEC of speed controller for example. In an electric model, the SPC could tap power from a 2S to 8S LiPo flight pack via the balancing lead. However, if you’re happy to use the conventional method of powering the receiver and servos from the same supply, this can also be accommodated by inserting a jumper plug into the SPC port that connects the positive and signal pins, enabling that option. More than just a receiver the inclusion of the SPC in the Optima receivers was timely because they do draw 190mAh, about 2-3 times more current than comparable receivers mainly due to the telemetry function where onboard data is broadcast back to the Aurora 9.Out of the box you get real time feedback on the receiver battery voltage or voltage supplied via the SPC which takes priority, so if tapping off the motor pack of an electric model you can see its voltage displayed on the screen of the Aurora 9. This is also linked to an audible alarm if the voltage falls too low to safely run the receiver, potentially saving a model. It gets better, there is a module or “Sensor Station” due out in the middle of this year that can be fitted with sensors for temperature (4 sensors), RPM (2sensors) fuel level, and GPS for altitude, ground speed and path plotting onto Google Earth. The Sensor Station is connected to the data port on the Optima 9 or Optima 7 receiver, which transmit this data back to the Aurora 9. Some of this data can be displayed on the screen of theAurora9 or with the optionalHPP-22 PC interface linking the Spectra 2.4 module to a computer, all the data can be logged and displayed in real time using the freely downloaded HPP-22 software. I can see telemetry becoming a feature that will be expected in radios in the future as flyers become more interested in what is going on in their aircraft. There are many examples where it can save problems and ultimately aircraft.

By making the Aurora 9’s 2.4GHz frequency module and antenna removable, they can be replaced with units namely the synthesizing Spectra Pro module and telescopic aerial for transmitting on the 36 MHz band (PPM and QPCM), so If you are like me and have a number of 36 meg receivers, they can still be used with the Aurora 9 after a module swap. If there is a new frequency band made available for model flying, upgrading the Aurora 9 will be just a matter of a module swap. The data port on the Spectra2.4 module and the Optima 9 and Optima 7 receivers are not only used for telemetry, but can be used to upgrade their firmware whilst the Aurora 9 can be updated likewise via the trainer jack. Again it’s the HPP-22 USB PC interface and free software that is used to facilitate these firmware updates so any software features not currently available can be included in the future. No need to hold off purchasing to see if an upgrade eventuates, you can buy now, upgrade later. For example, the Aurora 9 firmware Version 1.06 was released in early January as an upgrade from V1.05 that originally came with the Aurora 9. V1.06 features some fixes, upgrades and new functions including a screen lock which after activation means the screen won’t respond to quick (accidental) bumps that could change settings, a firm 2 second touch unlocks it.

What’s more, the HPP-22 lets you use a PC to download, store and even swap the settings from your model memories. I purchased the HPP-22 package and found it easy to use, just a matter of following the prompts and simple menu options. One quirk is that the HPP-22 interface has three ports, but only one is used for the current functions, the other two are apparently for future functions. I was also initially miffed the HPP-22 didn’t come with a USB cable, until I realised I had 3 floating around home that came with digital camera card readers so I didn’t really need another.

After the initial fondle, it was onto changing the unit from Mode-1 to Mode-2 and not having to open the case eliminated my usual mode-swap misery, in the past that blasted little centering spring was my greatest nemesis! Mechanically and electronically, the Aurora 9 is capable of accommodating the 4 standard stick mode configurations, plus 2 custom modes. Switching on, boot-up takes a couple of seconds, and you are first asked to check your frequency and if you want to transmit, selecting no means you can work on making adjustments without the battery drain of transmitting or if functioning with the 36MHz module you don’t need to take up the frequency, an icon on the screen and the green LED above the on/off switch lets you know you are not transmitting. Selecting yes means you are on air and you get the transmitting icon and a red LED. In bright Aussie sunlight, the screen contrast is good, even though the backlight has no affect, only coming into its own under dim light and backlight on-time can be selected to moderate battery drain.

The SPC cable is for supplying up to 35 volts directly to receiver to reduce the possibility of brown outs. I found no appreciable difference of in-flight performance in the 9ch RX and BODA between the 9 and 7 Ch receivers. Binding can be done in Normal or Scan mode ,but if swapping from one to the other receivers will have to be re-bound. I found that the receivers that hadn’t been rebound will see commands on frequencies still in common and will respond intermittently as they hop by. The bind button on the Optima receivers is also used to set up the failsafe function that cuts in if the signal is lost for more than one second. The failsafe commands the servos to move to a pre-defined position, I set mine to cut the throttle and centre all other servos. Not activating the failsafe means the servos will hold the last position. It was in the initial stages I came across my only problem after the mode change where the elevator control would not centre electronically, so it was back to Model Engines for a quick and easy potentiometer recalibration.

Programming includes a series of multiple choice questions, rather like a Facebook quiz! After selecting a new model memory and punching in the name on the qwerty keyboard 20 characters for naming models, using upper case, lowercase, numbers and symbols, you select and confirm the model type, ACRO ,GLID(gliders)and HELI. Selecting ACRO, for example, you’re then asked for the wing type with nine choices for standard and delta wing types for various configurations of aileron and flap servos. This is followed by the choice of tail configuration, normal, V or ailevator. Then comes the choices of single of dual engine, then do you have retracts, do you have airbrakes, do you have fuel mixture control? I was waiting for, do you want fries with that? Once that has been answered the channel assignments for the functions are displayed and their order can be changed. This is great if, like me, you want throttle on channel 1. For gliders (GLID),the choices are much the same, except it asks if you have motor control (rather than how many motors) and obviously no mention is made about mixture control. This TX makes setting up a 6 servo wing a breeze.

For helicopters (HELI),its quite a different list, first is the choice of six swash types, then questions are, do you have a governor, needle control and fuel mixture control? This sets up the basic programming configuration of the Aurora 9 to the model and I am hoping you are getting the idea by now of how capable the system is. Once this is done you comeback to the Home screen which displays the model name, type, the trim positions, transmitter and receiver battery voltage and the three timers. There are two main programming menu options the Model menu (aircraft icon) and the System menu , the folder icon is the Custom menu where you can place commonly used programming functions for more convenient access. In the System menu are the options for changing models and model configuration, setting up the timers, the trim steps, and the trainer functions, stick mode assignment, power management, output channel assignment and system information In all, highly customizable. Trimming and mixing is done in the Model menu. All the standard adjustable functions you would expect, reversing, sub-trim, dual rates, exponential and end-point adjustment.

A pointer tool for more accurate programming. and three timers are just one of the multitude of functions of the Hi Tec Aurora 9. Then there are adjustments for gyro sensitivity, governor control RPM or %,pitch curve 7-point, throttle curve 7-point, flap control, butterfly, aileron differential, idle down, servo speed, fuel mix, snap roll and throttle curve. There are more mixes than a superstar DJ. These include a suite of standard mixes such as aileron to rudder, aileron to flap, elevator to camber, camber mix, airbrake to elevator, rudder to aileron, swash to throttle, rudder to throttle, revolution mix and swash mix. These pre-defined mixes can be set up in different flight conditions and can be fine tuned on the fly using one of the three assignable trim levers. Conspicuous by its absence was a pre defined mix for rudder to elevator for sorting out pitch coupling in knife-edge flight. It can be set-up in one of the 8 programmable mixes but then it misses out on being adjustable by the assignable trims. Of these eight programmable mixes, three are 7-point with five 2-point and activation can be assigned to any switch. You can also choose to have any trim adjustments on the master channel transferred to the slave channel which is very handy and the speed of the mix can also be altered so the slave channel will respond faster or slower than the master channel. Where the mixing is really powerful is in the application of flight conditions. There are up to eight different flight conditions available for things like launching, landing, thermalling, speed, stunt,etc totally customisable in function and priority.

In each flight condition the primary controls can be assigned up to three different rate and exponential settings (24 possible in total) and in each flight condition, all the mixes can be different if needed. Very powerful stuff indeed. Whilst the introduction of 2.4 GHz spread spectrum technology has done alot to reduce the risk of radio interference, its still very good practice to perform range checks. The Spectra 2.4 module features a reduced power mode where transmission strengths cut from the normal 100 mWto just 1mW. Reduced power mode is activated by pressing and holding the bind button for 2 seconds and it then operates for 90 seconds, with the module sounding a rapid advisory beep, changing to a solid tone when you go out of range. This leaves both hands free to wiggle the sticks as you walk away from the model. The button can be pressed again to return to normal operations before the 90 seconds is up. I did find once that I accidentally engaged the binding function when trying to do the range test, something to look out for. All my pre-flight range checks went well beyond the recommended safe thirty metre minimum, some up to four fold. I tried to see how much the reception could be challenged by mounting both antennas of the Optima 9 together on to one of the 3S LiPo battery packs of my Extra 330L, which also meant they were just below the 60 amp speed controller and just behind the 50 mm out-runner motor. With the receiver antennas placed in this ridiculous position, and the motor running at part throttle(when brushless ESC’s are at their electrically nosiest I was able to achieve fifty metres of range from in front of the model where both receiver antennas were pointing straight at the transmitter. This was still well in excess of the safe range, but I still would not fly with them in that position.

There really is little left to say here. I focused on using two “average” models for flight testing as they both had been flown without problem on 36 MHz and another brand of 2.4GHz gear so they would give a fair comparison. I flew in Normal and Scan modes, with and without SPC power and didn’t have an issue at any stage with either the Optima 9 or Optima 7 receivers, I couldn’t feel any difference in connectivity or response. But don’t just take my word for it. The MAAA take safety very seriously and run challenging tests on radio equipment. The AFHSS system has their full approval for club operations. Finally, are two BODA’s better than one? It was toward the end of the review my curiosity got the better of me and I purchased an Optima 7 receiver to see how much difference there was between the performances of the single verses the twin antenna set-up. I admit my testing methodology was a bit unscientific, but it satisfied my curiosity. The Optima 9and Optima 7 were set up with their antennas mounted side by side and bound in Normal mode to work in tandem to move a servo each. My aluminium transmitter case was used as an RF barrier, right in front of the receivers between them.

I have had over 2 months use of the Aurora 9, fact-finding, fiddling and flying and still I feel I have only just scratched the surface. I lost count of the times I found myself thinking, wow that’s clever, or, wow that’s handy! It’s clear the Aurora 9 has benefited from its longer gestation and with functional flexibility, upgradeable software and replaceable modules, it has backwards compatibility and, a high degree of future proofing, ensuring it will deliver now and keep pace with the competition as there is still more goodies to come. It’s a strong package that is hard to beat.

The Hitech Aurora is distributed to hobby shops by Model Engines Australia telelphone 03 8793 5555 www.modelengines.com.au

Available from

Reproduced with permission from Model Engines, minor editing of information by Hayden Daley January 2012
Hi tec 2.4 GHz telemetry
by Dean Williams
Telemetry is shaping up to be the biggest thing to happen to RC aeromodelling since the broad up take of 2.4 GHz radio gear. Whilst telemetry in RC aeromodelling is not new then, neither was 2.4 GHz what is driving this RC information revolution is that it is becoming so readily available.

Hitec was the first of the major RC radio manufacturers to bring telemetry to the masses with the introduction of the Aurora 92.4 GHz transmitter and Optima receivers with in built telemetry that reported back to the transmitter the voltage of the receiver power supply, great info to have. This was only a taste of bigger and better things to come they have released a comprehensive telemetry package compatible with the Spectra 2.4 module equipped transmitters such the Aurora 9 and Optic 6 and Optima-7 and -9 2.4 GHz receivers. The package features sensors to collect information on temperature, RPM , fuel level and a GPS collects positional data that is used to calculate altitude and ground speed.

If you have an Aurora 9, the telemetry information can be displayed on its screen in real time. On top of this, the Spectra module can be connected to a PC so the telemetry data can be recorded during the flight and stored for later analysis. Being a “gadget geek” this technology had instant appeal to me, but does it have substance to back it up?

The package, this is the full “Nitro” telemetry pack under review here and features the Sensor Station, four temperature sensors, optical and magnetic RPM sensors, a fuel level sensor and a GPS receiver. However, there are basic telemetry packs available that feature the Sensor Station, a pair of temperature sensors and one of either the two RPM sensors and the individual sensors are available separately temperature sensors come as a pair for those who want a different mix.

The first impression of the equipment was how compact it was. The Sensor Station itself is 34 x 24 x5 mm, weighs in at 7.1 g, and is the heaviest single item in the package. Next heaviest is the GPS sensor at 7 g, then the fuel sensor at 5.6g, the optical RPM sensor is 4.4g. Each temperature sensor is 2.6 g and the magnetic RPM sensor is 2 g. The Sensor Station has sockets to take all eight sensors and there are sockets for the data cable connection with theOp­tima7 or -9CH RX (cable included).The power socket that takes a servo extension lead fitted with male servo plugs (supplied) which can be connected together as a spare output on the receiver, in parallel with a servo using a Y lead, or straight off a battery pack (4.8 – 8.4volts, 2S Li Po max.).

The GPS sensor has a heat shrink wrapper and looks like a rather innocuous little black box, despite the technology inside. The fuel sensor is made up of 2 parts the, electronics on a circuit board wrapped in heat shrink tube. The actual sensor pad that attaches to the outside of the fuel tank and reads the level of the fuel. The package included three fuel sensor pads of different sizes to suit tanks of different volumes. Each pad has two sets of contacts, either of which can be plugged into the circuit board to collect the information. The pads are double sided and coated with an adhesive, which can be used multiple times and there are four segments pickups on each pad to sense through conductivity where the liquid is in the tank.

The optical RPM sensor works on the same principal as the hand held tacho units most of us are familiar with, but it does work over quite a distance ,up to 150 cm, and its mount is shaped to fit nicely on the boom of a helicopter and point up to detect the main blades. The magnetic RPM sensor is designed to be used where space, drag or weight can be an issue for the optical sensor. The magnetic sensor needs to have a small but strong magnet attached to the rotating part you want to clock..Three small rare earth magnets are supplied, these need to pass within 1 mm to trigger, the sensor. The temperature sensors are loops of wire with a thermo couple embedded half way round, 3 bands of silicone are wrapped around the wires to keep them neatly together but they can be parted towrap the sensor around an object like an engine head and they have an operating tempera­ture of -40 to 200 degrees C. All the sensors, except the temperature sensors come with double sided mounting tape, though I prefer to use self adhesive Velcro. There were no detailed instructions in­cluded, just a double sided A4 sheet which briefly describes the specifications, installation and general information, so there will be a bit of suck it and see.

For the review, I drafted my Phoenix Tiger 3, a classic “40” sized sports model that I had converted to electric power on 4S Li Po’s, already fitted for the Aurora 9 and Optima-9 receiver. Three temperature sensors, ESC, battery and air, optical RPM and the GPS were installed. The biggest grumble I had with the installation was the leads on the sensors came up a bit short, a temperature sensor wouldn’t reach the motor and I would have preferred to have the optical RPM sensor mounted closest to the prop, but it was still in range. Hitec are working to make extension leads available, but in some cases, longer leads will affect sensor operations and that needs to be worked around.

With all these sensors running, the current draw was 3 milliamps so they won’t have any noticeable impact on battery life. Speaking of battery life, let’s not forget the receiver input voltage is also part of the telemetry package. The voltage supply into the Supplementary Power Connec­tion (SPC) takes priority in the telemetry transmission overpower supplied through the servo connections. Through the SPC, the receiver can handle up to 35Volts, equivalent to an 8S LiPo pack, so by tapping power off an electric flight battery say, through the balance plug of a LiPo to power the receiver through the SPC, the voltage is sent back to the transmitter for viewing and even recording on the PC.

A low voltage alarm can be set both on the PC and the Aurora 9 to indicate when battery power is running low and it’s time to land, That feature will certainly save some airplanes. Besides a Spectra 2.4 module equipped transmitter and an Optima-7or -9 receiver the Optima-6 receiver doesn’t have a data port, the other piece of gadgetry you will find very handy I know I do is the HPP-22 USB interface. This lets you connect the Aurora 9, Spectra 2.4 module and Optima-7 and -9 receivers with a PC, to update firmware and move model settings on and off the Aurora 9. In this case, it also lets you view live and log the telemetry data onto a PC, as I said very handy.

The software driver for the HPP-22 and all firmware updates is available to download free from the Hitec website (www.hitecrcd. com) and the driver is also required to be able to log the telemetry data. Indeed, to use the telemetry, I had to upgrade the firmware in my Aurora 9 to version 1.07 and the firmware in the Spectra module and the Optima-9 receiver to version 2.0. Of course, you don’t need to lug around a laptop to view the telemetry in real time

The information can be displayed on the screen of the Aurora 9, with options of which sets of data you want displayed , such as GPS, temperatures, RPM, battery voltage, or a collection of all the main information streams on one screen called Cockpit. Some of the data is retained by the Aurora 9 in a buffer so at the end of the flight, the maximums and minimums for the voltage and temperatures can be recalled and the last reading for all the sensors is retained. If there is a break in the data stream , which can be handy in the event of a beyond visual contact ground impact, a model goes down in the proverbial cornfield, the accuracy of the GPS presents an opportunity to locate a lost model. Or at least the bit with the GPS gear!

Though I only fly Electrics, I was curious to see how the fuel sensor worked, at least on the bench. I had an old fuel tank that I filled ¾ with water and stuck the fuel sensor pad on it. It took me a while to work out how to properly attach the sensor pad to the sensor circuitry, I finally found that the clips on either side of the clamp had to be released so the pad contacts could slide into the clamp, then the clips were reengaged. The fuel sen­sor worked fine with the water, even with a little shaking. However, with vigorous shaking, the sensor read the tank as full. Interestingly, the sensor was smart enough to know if the tank was upside down, it still read the correct level.

For the test flights I did indeed drag my laptop down to the flying field and set it up on the flight line. I had made up a 1.3 metre cable to connect the Spectra module in the Aurora 9 to the HPP-22 to stand a comfortable distance from the computer. However, hardware for a wireless link has just been announced by Hitec to do away with the tether which is a good idea. The software interface to display the telemetry data on the PC is reasonably intuitive; the main function is the dashboard display of read-outs coming in from the sensors, in numerical and graphical format. There are some options to change the dash set-up, such as displaying in metric or imperial, labeling the temperature readouts, setting alarms for low voltage and high temperature, etc. However whilst I could customize the tacho range (I set it to 15,000 RPM) the dial on the dashboard continued to max out at 10,000. It takes the GPS a few minutes to get a lock on the satellites so you need to let the model sit whilst its does this. Then it’s hit the telemetry record button and up and away. For testing I went through a fairly normal flight routine, basic aerobatics, a few touch and goes. The guys at the club would gather around the computer and read off my height, speed and heading as I was flying around and count down the height as I was coming into land, which was interesting. I have to admit, I wasn’t comfortable taking my eyes off the model to look at the screen on the Aurora 9. Hitec are onto this, and are releasing a voice module to plug into the Spectra module and verbalise the readings, like a car GPS. After landing, I stopped the recording and saved the data.

This is where the imagination can run wild. With each flight logged on the PC three files are created. A .txt (text) file that contains all the data logged referenced against time(2-3 data sets per second), and two .kml (GPS) files. The .kml files are compatible with Google Earth, which can be downloaded free from the Hitec website, and you need to be on-line to use it. The only difference I could see between the two .kml files is that during playback on using the Google Earth controls, it was interesting to view the flight path from different angles, what surprised me was how much of a “corkscrew” my loops were, I knew they weren’t neat, but ,I didn’t think they were that far off track! The point is, the plots could be used as a training tool for aerobatic pilots to record maneuvers and see how precisely or not they were performed. With practice, you could expect improvements to be seen in the plots over time.

The play-back of the flight can be paused, and with a click on the aircraft icon, this brings up a window showing all the gathered telemetry data at that point in the flight. If you don’t have access to Google Earth, theHitec software has a function to generate its own 2-D flight path trace that looks a bit like a radar screen. I did come across a persistent and slightly annoying bug in the software that affected the .kml files. A few minutes into each of my flights, the GPS latitude readings suddenly went positive, sending my flight path into the Northern Hemisphere. Hitec are aware of this and are working on a fix. The .txt file contains the information for the on screen dashboard, where the fight records can be replayed in slow motion, normal time or fast forward. Interestingly, this wasn’t affected by the bug affecting the .kml files as the GPS records remained in the Southern Hemisphere. The data in the .txt file can also be converted to an Excel spreadsheet without too much work, though it takes a little figuring to work out which column contains what data. This then makes it easier to extract and manipulate the data from each sensor and plot it graphically. Of general interest is what was the maximum height and speed reached during the flight, and this can easily be found.

The caveat for the speed records is that its ground speed, and it’s interesting to see, in the plots, the speed fall to almost zero when doing vertical maneuvers, then suddenly shoot up as the aircraft leveled out. The RPM records had a few spurious readings, I guess the optical sensor had trouble sometimes with ever changing contrast and the odd look into the sun, I expect the magnetic sensor to be more stable. The temperature records show I had pretty good cooling for my power system, with temperatures climbing very little above am­bient. Had something started to cook the temperature sensors would have set off the alarms I had set, well before any damage was done. This highlights how the telemetry is more than just another fancy piece of aircraft “bling”, but can actually play a role in preventing damage to an aircraft.

I have already mentioned the wireless link to record the telemetry on a PC and the voice module. Adding to these upcoming releases is an electric flight package with its own Sensor Station (the Sensor Station Blue) featuring sensors for picking up electric flight pack voltage and current up to 200 amps using a loop or ampclamp so not in-line. These replace the fuel level sensor in the Nitro pack but all the other sensors stay in the Blue version. I suspect there will be further releases by Hitec over time to add more features and function to the telemetry package.

Whilst I can tell you a lot about what this telemetry package can do, I can only tell you a little about what it can be used for as it’s only limited by imagination. The equipment has so much potential to enhance the enjoyment and safety of RC flying. Viva the information revolution!
The Hitec Telemetry System is distributed to hobby shops by Model Engines Australia

Available from

Reproduced with permission from Model Engines minor changes and editing of information by Hayden Daley January 2012.
CM Pro Habicht
by Danny Malcman

After the first world war, the Germans were not allowed to have an air force, so they concentrated on gliding. This is how they were able to build their Luftwafe so swiftly. Reportedly the the fully aerobatic Habicht was designed by Hans Jacobs and the first debut was at the 1936 Olympic Games in Berlin in 1936, where it was flown to everyones amazement by no other than Hanna Reitsch and Heinz Huth (World Gliding Champion 1960). Hanna Reitsch also flew the Habicht and inspired audiences at the Cleveland Air Race in 1938 in the USA.

My friend and mentor John Gothchalk, just happened to come and witness the maiden flight of the review model, John testifies that he was present during the 1936 Berlin Olympics and has vivid recollections of the above mentioned famous flight display of vertical dives bunts and inverted exits in front of the spectators at the Olympic pavilion before landing else where outside. I think it deserves to be mentioned that, John Gotchalk was honored by the Scale Soaring Association with a plaque which distinguishes him to be the foremost person who pioneered aero towing of scale gliders in Australia.

To my amazement, the full size Habicht wingswere sheeted with “diagonalgrain” 3mm plywood, how futuristic is that? The full size weighed 250 kg with a wing Span 13.60 metres and a gull wing configuration. It featured an open cockpit and the main purpose was for competition soaring and aerobatics. With the releasable dolly dual wheel undercarriage it was later used when training for landing the rocket motor powered ME163 comet in a special clipped wing version called “Stummel Habicht”..

Construction /Assembly sequence
First make yourself a model saddle for supporting the model during construction and later for transporting the model to the field, hence the bottom semi enclosed section serves as a storage compartments for essential parts like the wing joiner tube, this way nothing gets left at home when you go flying. Alternatively you can use a polystyrene fruit box which works out cheaper and simpler, however is a lot wider.

Also very practical inexpensive protective wing jackets can be simply made from “bubble wrap”, try to get the sealed cell type however the stuff sold at Bunnings and Office works , is less durable but still acceptable, the seam is sealed using a straight edge and a heat gun.

Next decide if you need a tow release mechanism, if so then one more servo will be required to be mounted somewhere. Another option is a skid as per full size, it is worth considering especially if the field you fly from has a rough surface. The full size never had a fixed or otherwise main undercarriage wheel, the two wheel dolly was used for launching and was relesased almost immediately after lifting off the ground.

The removable cockpit is as per full size. On the model it is held in place by strong magnets and located accurately with pin. This allow good access to the radio gear just like a removable canopy. The fuselage magnets are already glued in the frame, however the removable cockpit magnets need to be glued in.

There is a small catch here, the magnets by nature are polarized, therefore make sure you glue the magnets the right side up, otherwise the cockpit will eject instead of being held in place securely. Do this by first positioning the magnets on the fuselage opening and allow the fixed magnets to attract the mating part. Then number the top surface 1,2,3 and 4 with a marking pen before gluing to the removable cockpit with epoxy.I would recommend to attach an elastic umbilical cord to prevent the loss of the removable cockpit, although so far it has always remained in place after landing.

Trial fit tail and wings and check for rigging inaccuracies, it is not unusual too find small inaccuracies even in more expensive European kits with molded fiberglass fuselages, the wing inner panels should always be checked out to have identical angle of attack for left and right. I had to make a small adjustment to one of the stabilizer alignment rod exit holes, the wing saddle accuracy was good. The angle of attack was measured at 1.0 degreee positive, this should result in a glider capable of flying a wide range of speeds.

After the rigging was checked, the horizontal stabilizers were assembled and glued with slow setting epoxy. Excess glue was cleaned with methylated spirits and rigging re checked before the epoxy was allowed to set. Next prepare the fabric disc hinges by inserting a drawing pin close to the center, this will ensure that the disc is inserted equal distance in the slot. The elevators were then glued to actuators with epoxy and assembled without gluing the fabric disk hinges, scrap plastic sheet strips where inserted between the actuator wire and the stabilizer to keep the epoxy off the stabilizer flase trailing edge, again use methylated spirits to clean up and then hold the elevators snug in place using rubber bands and scrap balsa to ensure the air gap is equal on both sides and leave epoxy to cure. Once the epoxy was set the hinges were glued using CA to attach the surfaces.

Rudder knuckle hinges require sinking in to ensure that the rudder hinge point is where it should be, this can be checked before gluing by trial fitting to the tail post. When happy with the hinge position then glue hinges to the tail post using 1.5 mm balsa shims to ensure that the rudder does not rub against the tail and again leave epoxy to cure

Next dry fit the rudder and check operation before gluing the tail post with epoxy, the tail post should be set back inside the vertical stabilizer a little less at the top where the hinge radius is less. Again clean up with methylated spirits and clamp using a large number of clamps to ensure a bump less surface and leave epoxy to cure. Carefully apply a little bit of petroleum jelly (Vaseline) to the hinge knuckles to prevent epoxy from gluing the hinges solid whilst keeping the exposed hinge barbs clean. Apply epoxy to the hinge holes using a toothpick, as well as the hinge barb before mounting the rudder then clean up with methylated spirits. Check that the gap is as close to 1 or 1.5mm and leave to set. The wing aileron servos installation is straight forward, just use a 600 mm extension on each side.

Spoilers are operated by a mini servo inside each wing panel. I did not like the recommended method of servo fixing using double sided tape. In the past I have used epoxy where depth was limited, however in this case I made a wooden saddle and fixed the servo using an aluminium strap. The wing servo connection is best done using special four pin dean plugs or 9 pin ‘D’ connectors, this will simplify the model assembly at the flying field.

The optional ‘tow release mechanism’ was made using the KISS (Keep It Simple) principle, using tight grain hard wood block of 12 to 16 mm square and 40 to 50 mm long. Simply drill a 3.2mm hole along the length and a 10mm hole across near one end. Insert a short length of Sullivan brand yellow inner push rod up to the large opening, then use a 1/16” or 1.5mm music wire as an actuator. Cut a 3 by 8 mm slot for the towing loop at 40mm from the nose tip on the lower side (in plan form view). Shape the wooden block to conform to the curvature of the fuselage before gluing in with epoxy. Apply epoxy mix and hold the mechanism in place using a short piece of cooper wire instead of the fishing line towing loop and insert the actuator rod, clean up fuselage exterior with methylated spirits before twisting the cooper wire around a wooden dowel to hold the mechanism securely in position until the epoxy hardens.

Appearance; this is a very attractive model finished in glossy two pack paint on the fuselage and colour matched plastic film covered flying surfaces. Hardware supplied is of good quality and did not require to be upgraded, the supplied elevator push rod looks like hollow tube made from carbon fiber, the rudder horns are knuckle type similar to the Robart brand. Mine my finished up weighing nearly 4.0 Kg including skid, dual batteries and tow release.

The following may be common knowledge to some, but I’m sure it is valuable knowl­edge for those still interested in this sphere of RC modeling discipline. Aerotowing, considered to be the safest method for maiden flights of scale gliders the discipline of aerotowing a scale glider is similar to that of flying a powered model. Where the landing is planned and executed using the rectangular box method, just like in full size airplanes. You don’t just plonk in anywhere in the paddock like some model glider pilots who seem to be unable to change the habit. Model aero towing was not always without it’s problems, valuable lessons were learned in the early days, high attrition rates were soon attributed to (a) under powered tugs, (b) the lack of redundancy in tow release mechanisms and (c) inexperience. Today without a doubt it is the safest and most reliable method of launching scale model gliders of various sizes.

Launching of new models off a slope where the presence of good lift is first verified by other models, is also considered to be one of the safest methods for maiden flights. The constant updraft provided when the lift is on sloping offers the pilot a more relaxed time to assess and trim new models. However landing sites on slopes can be a much harsher environment for scale gliders, mainly due to ground surface quality and the unpredictable nature of the air close to ground. In any case, good slope sites are not in close proximity for most of us who live in the big smoke. Having said all that, slope soaring is just amazing, exhilarating and contagious, you just don’t get tired of staying up in the air sometimes for hours, a number of my friends often do it even when it’s too cold to leave the house, and some others who practically live on the slope.

Winch launching of scale gliders was once the common practice, before aero towing become refined and the dreaded attrition rates have since diminished. Winch launching has a couple of serious drawbacks firstly the lack of directional stability during the initial roll out, because the tow hook position needs to be just in front of the C of G in order to achieve good launch height whilst the other is the tendency of one wing slipping under adjacently positioned winch lines, inevitably causing serious damage. There are however several alternate tow hook arrangement methods available to mitigate the stability problem, therefore winch launching can still be a viable solution where suitable tow planes are not available, but this is best done by experienced modelers before attempting to go on your own.

Maiden flight tests were carried out by aerotowing on a mild winter day, the model needed virtually no trim, the 1.0 de­gree angle of attack and the recommended points C of G range are obviously very close to optimum. The model proved to be stable and responsive, with no apparent tip stalling tendencies, however it is best not to be stalled to low due to height lost before recovery.

The Habicht will fly fast when required and penetrate up wind with ease. The spoilers are very effective and do not require elevator compensation. I am very pleased with the model overall, in my eyes it one of the more attractive vintage saiplpanes which didtinctly stands out among the crowd.

Very attractive modern looking vintage scale glider model now available in ARF Effective spoilers make landing easier. Suits an intermediate to advanced modeler, not a beginners model. Launches with ease on aerotow and thermals with the best of them. Absolutely no vices, relatively easy to fly and land It has a good turn of speed as was be expected according to the chosen low angle of attack It can be flown slowly and circled in a thermal without any apparent tendency to fall out and it lands with ease.

The CM Pro Habicht is distributed to hobby shops by Model Engines Australia 03 8793 5555 www.modelengines.com.au

Available from

Available from

FlyDream 2.4GHz radio gear – Reviews reviewed and more...By Hutton Oddy
Various technical and practical reviews of Fly Dream 2.4GHz radio gear have been published over the past 12 months by RC Model Reviews, Airborne Magazine and Radio Control Model News. This article describes a different part of the story. It tells why I became involved in importing Fly Dream products, and describes some of my experiences. Why did I consider using Fly Dream rather than the big brand name gear? I had a lot of models, the potentially high cost of conversion; so thought it might be worthwhile exploring something different to the big 2, JR/ Spektrum or Futaba. The primary driver was price and reliability, the age old cost versus benefits equation.

I fly gliders, electric models and a few smelly diesel powered old timers. The radios I use are JR and Graupner. I like using them, they do exactly what I need; and I did not want to change to new transmitters. Over the years I had learned that using the same brand name receivers as my transmitters was not necessary. I had used FMS, Shultze, Hitec and Corona receivers without any problems. This made me aware that you could venture away from the big brand names without incident. In fact, the Shultze 835 was the most bullet proof 36 MHz receiver I used in my gliders and demonstrated to me that after-market radio gear could work better than the original, so I was ready to experiment.

Sometime around mid 2008 I tried the first series of Corona 2.4GHz, after all their crystal based 36MHz receivers worked extremely well. It was not a good experience. I experimented with a number of other low end systems, which worked on the bench, but was not confident enough to try them in the air. I didn't need to, the Shultze 835's worked flawlessly with my JR and Graupner transmitters; the only problem was sometimes having to wait to fly and stepping on the antenna.

In mid 2009 I read a review of the Fly Dream 2.4GHz system by Bruce at RC Model Reviews. It was promising enough to rekindle my interest in 2.4GHz radio gear. At that time it claimed to be a frequency hopping system, but in practice it was a 3 band DSSS system compared with Spektrum's 2 bands. There were a number of problems with the gear; the receiver was often swamped at close range which made binding tricky and servo movements were sometimes jerky. But it was promising enough to contact the manufacturer to see if they intended to fix these problems and to get some other receivers to try. Eventually, I obtained some improved modules and receivers, in retrospect these became V2 and started my own tests. I was impressed with the small lightweight receivers, the range and the smooth servo response. I was also impressed that the manufacturer was prepared to listen to customers and to correct things that were not as good as they could be.

Between August 2009 and early 2010 I spent a lot of time testing Fly Dream gear. I covered the range tests and practical aspects in models and a friend with extensive professional experience in telecommunications helped with the technical evaluation. His view at that time was that Fly Dream gear was good enough to pass MAAA tests, but needed a few improvements including a reduced power “range” test facility to make it truly useful.

In contacting the MAAA they were happy to test it with the intent of listing it as approved in MOP 058. They also needed FCC certification, which was obtained in February 2010. To accommodate feedback from the reviews and modellers, Fly Dream over a period of 4 months added a switching power supply and a range check button to their transmitter modules, changed to a 19+ channel FHSS protocol which was designed to dwell around three broad areas of the 2.4GHz frequency spectrum to ensure backwards compatibility with their earlier products, and completed the testing protocol for FCC approval. The MAAA added Fly Dream to MOP 058 in March 2010, this improved version was designated V3. In March 2010 my fledgling micro business had its first sales of Fly Dream 2.4Ghz radio gear.

With any new equipment I am naturally cautious. I continued to flight test Fly Dream 2.4GHz gear, migrating to my Open Thermal models, home built and Vladimir Supra in March 2010. This was a big step. As you know competition gliders use lots of carbon fibre, fly a long way away, often 1.5km or more and cost more than the average punter would spend on a model. The Fly Dream system has been extremely good and I have flown in many glider competitions, Jerilderie, Armidale Expo and the Nationals without any radio problems. With the larger competitions there are often 10 other models in the air at any one time, many of these use different brands of 2.4GHz radios.

As with any 2.4GHz system careful attention needs to be paid to antenna placement. I experimented with a number of alternatives and found that putting the ends of the antennas outside the fuselage at 90o to each other gave the best results. Despite this, I have had one receiver hold, the radio went into failsafe mode at 1km distance and 300m altitude, which recovered when the model turned more side on to me. The model was flying away from me, one antenna was blanked by the carbon boom, the other was pointing directly at the transmitter and I was inadvertently pointing the antenna towards the model. In the two most recent March and April 2011 RC Soaring Digest magazines there are articles on antenna placement and trouble shooting 2.4GHz systems. These are must read articles for modellers using any brand of 2.4GHz gear. I strongly doubt that any brand of 2.4GHz radio would have avoided a hold under such conditions.

In conclusion, I am extremely happy with Fly Dream 2.4GHz radio gear. It has worked in every situation I have tried it in. There are many happy customers who also like the cost / benefit equation of Fly Dream. Although Bruce from RC Model Reviews said in his most recent review, it just shouldn't work as well as it does, the good news is it does work extremely well!!!
Hutton Oddy March 2011
Available from

Available from

Minor changes and editing of text for use in Thermal Circle.com by Hayden Daley January 2012

That’s it for this edition of the Thermal Circle, I hope you enjoyed these detailed reviews and many thanks to Model Engines for allowing this information to be used.
Hayden Daley January 2012.

Click on any banner ad to transfer to the website

Text-based competition soaring information website established 2007