IFly4 Quadcopter and Rabbit Flight Controller ARF Set Review

May 9, 2012 7:32 | By | 16 Comments

A complete, receiver-ready quadcopter for 240 bucks? That’s what GoodLuckBuy is offering, but can this ready-to-fly package really satisfy, or is it a useless china gadget? Find out in our review!

That’s what GoodLuckBuy is offering with their IdeaFly IFLY-4 frame complete with Rabbit flight controller, four 2208 1200kv brushless motors, four 12A ESCs, an ultrasonic altitude sensor and all the wiring and accessoirs you need. Best of all, they sell this as a receiver-ready version, meaning that all the soldering, cabling etc. has been done for you. GoodLuckBuy also offers a cheaper version with the FF controller instead of Rabbit. But for now, we’re reviewing .the Rabbit version

So is this quadcopter from the bargain bin, or for the thrash bin? And what’s all the fuss about the alleged GPL violation by the Rabbit developers? Read on to find out!

The IFly4 with FPV gear installed. The FPV box contains camera, transmitter, GPS, OSD and current sensor and can be easily swapped between models.

 

The Hardware

The Rabbit flight controller is quite a complex board with a NuvoTon 50MHz Cortex M0 processor, 3D accelerometer, barometric sensor, lots of LEDs and pins: there are connections for the supplied ultrasonic sensor, but also for external LED strips, GPS, battery balance plug and much more. You get everything you need here, including a nifty ESC connector board with the ESC power wires already soldered onto. For the amount of wires, it still looks quite tidy where it counts.

The IFLY-4 frame is incredibly sturdy and excellently designed. There are support ridges on every strut, the whole upper part is insanely rigid while the landing skids are very flexible and soften even the worst landings. Best of all, they snap on instead of being locked into place, so if anything bad happens, chances are you can just clip them back on and continue flying instead of having to repair the frame. The controller is securely tucked away in the center of the frame, very well protected from even the fiercest impact. The front arms are colored red – much better than having to stick a ping-pong ball somewhere like on other frames. This 450-sized frame gives you one of the best bang/buck ratios right now.

The frame as it came out of the box, with the arms moved into flight position

The frame is collapsible and the arms can easily be locked and unlocked in position. The securing mechanism is sturdy and won’t cause surprises during flight. Comments on the GLB forums indicate that there would be work to do to get this frame flight-worthy, this was not the case in our review unit. The canopy is a bit flimsy but if you’re doing anything meaningful with your Quadcopter like FPV flight, you won’t have much use for it anyway.  Still it’s nice that there is one included.

The underside exposes the ESC connector board. All solder connections are pre-soldered and there is little left to do

Of course it’s not all dandy. While the controller is not in the way of payload and batteries above and below the center area, the fact that there’s a giant hole in the center is both a blessing and a curse: On one hand you have easy access to the controller board at all times, on the other hand it’s difficult to use the available area for payload because you have to secure it around the edges of the center platform.Things are better on the bottom, though the landing skids are in the way if you want to mount the battery down there. And if you plan to use the supplied ultrasonic sensor, your options for mounting payload below the copter are reduced even further. Since this is a 450-size frame and the props are quite large (9 x 4.5) you have to stay close to the center or risk having a prop chew on your cables.

The miniscule 12A ESCs are hidden in the underside of the arms

The unit we received from GLB was put together very well. The soldering was a bit iffy but in general, all screws were accounted for and the important parts were secured nicely. You have to choose your own location for the ultrasonic sensor, and the supplied zipties are the worst we’ve seen yet – but nothing a bit of doublesided tape and stronger zip-ties can’t fix. All in all, completing the “build” takes all of 10 minutes, and the hardest part of that is to figure out which channel on the Rabbit board goes to which connector on your receiver.

The 1200kv motors provide plenty of thrust and are well fixed into place with four screws

 

 

The Software

Rabbit’s controller board has a mini-USB connector, and the whole set comes supplied with a USB cable too. Unfortunately you will not find any printed manual or even a CD. You have to google for the software and manual, or hope that the links on goodluckbuy.com don’t disappear. That’s disappointment number 1.

Disappointment number 2 is the fact that the software only runs on Windows XP. Running Windows 7, Vista or even Win 8? Prepare to dig up an old XP computer or install XP dualboot, otherwise you’re out of luck. Disappointment number 3 is the upgrade policy, it’s difficult to find out what new firmware versions exist, what the changes are, and there’s an ethical dilemma with how the software was developed. But more on that later.

The rabbit controller with added barometric pressure sensor board. The manual recommends covering the opening of the sensor with a piece of foam to minimize the effects of wind on the altitude hold function

The good news is that the board came pre-configured with pretty much all the right settings. Whether this is true for all units sold by GLB we cannot say, but the fact is the factory defaults worked out of the box for us. That is very important, and a big improvement over the old KK controller board for example. There’s a couple things you have to watch out for:

1) Set your throttle range to -110% to +110% – otherwise the controller will not arm.
2) To arm, plug in the battery, wait, then move the aileron stick to the left for a moment (the controller will beep), then wait until the LEDs “breathe” (fade in and out slowly), then move the aileron stick to the left again and hold it there for 3 seconds. The controller will beep again and is now armed. You’re ready to fly!

You can fly this baby with just 4 channels, but connecting channel 5 lets you select your flight mode, and channel 6 will allow you to toggle the altitude hold and “carefree” feature. Use three-position switches for both, since each has 3 modes.

The flight mode can be switched from tame to medium and “3D”, where 3D lets you do flips and rolls and does nothing to prevent you from crashing, but also gives you the highest level of control.

Altitude hold keeps the copter at the current altitude as long as you don’t mess with the throttle too much. Just enter a brief hover and it will stay at that altitude. This feature uses the ultrasonic sensor for heights up to 2 meters, and switches to its onboard barometric sensor if you’re above that altitude.

“Carefree mode” is a weird feature, basically it makes the quadcopter always fly away from you when you push the stick forward, and back towards you if you pull the stick back – no matter the orientation of the quadcopter. An interesting mode for beginners but it requires calibrating the integrated compass module, and it’s useless for FPV or aerial filming.

The ultrasonic altitude sensor works for altitudes up to about 2 meters, above that the baro-sensor takes over.

 

GPL Violations

Rabbit’s software is, in part, based on the work by the MultiWii team. This would not be an issue, were it not for the fact that said software is licensed under the GPL, and one of the conditions of that license is that if such code is used and/or extended or improved upon, the resulting software also has to be released under the GPL.

It is not unethical or illegal to sell GPL-Licensed software. Many companies make a good living and have millions in revenue thanks to open source and GPL-licensed software. However, it seems Rabbit used that code without fulfilling the core requirement of the GPL – their modified source has not been released.

A preliminary analysis with IDA Pro confirms that for example the GPS code and the mixer functions is more or less a direct port, and heavily based on MultiWii’s implemetation. There’s always more than one way to code things, but not only do the function signatures match (except for the usual differences when moving to a different processor) but the structure of the code is often identical as well. The fact that modifications were made is irrelevant, if the software is based on code that was released under the GPL, they are legally obliged to release their sourcecode as well – and since there’s no linking exception, Rabbit would have to release their entire code, not just the parts they used from MultiWii.

Several notices were posted by MultiWii teammembers on rcgroups.com and similar forums, and reactions were peculiar: Aside from several sympathetic comments, the majority of responses fell into the “don’t care” category, or were just plain wrong in their assumptions of how copyright works, how the GPL works, and basic things like the difference between Trademark and Copyright. Few understand the problem this situation creates: Without releasing the sourcecode, Rabbit forces their users to be dependent on their updates. Next month they could decide to no longer update their software, and then you are stuck with an expensive board that will then do less than that $50 MultiWii board that just so happens to still receive software updates for years to come.

There is no doubt that Rabbit improved the MultiWii code as well as the hardware: The stability of this controller is remarkable, they ported the code to a 32bit ARM microcontroller, the altitude hold works very well… but it remains to be seen whether they decide to do the right thing and fix their GPL violation, or stick to their current practice of ignoring the issue.

Why should you care? Because Rabbit’s behavior frustrates the developer community and removes their incentive to push ahead with new developments. In the long run this means you’ll have to pay more, won’t get as many features, and firmware updates won’t be available for your board for years to come.

 

Flight performance

The factory parameters were fine for the IFly-4. Hover is extremely stable, even takeoff from angled positions is possible without any trouble. It is possible to reach speeds of up to 60km/h using the normal (stabilized) flight mode. Rudder reacted relatively quick but still very manageable for beginners. The props came pre-balanced, there was little to no vibration to speak of.

Switching to the “enhanced” flight mode makes the craft a little more responsive, quicker to turn, but still stabilizes general flight rather solidly. If nothing else, this mode makes most sense in windy conditions as you have more means to hold your position.

And then there’s 3D mode.  As soon as you flick the switch, the training wheels come off: The nimble and tame quad turns into a beast that does everything you ask it to, and then some. Thrust is plentiful so rolls and loops just beg to be made, top speed goes to 80km/h and above! This makes it practical to follow even medium-speed planes to a certain degree.

Most impressive was the turn performance. The phrase “turns on a dime” really fits here: You better make sure your payload is secured really well or you’ll risk throwing off your battery. Flying this baby in 3D mode is a ton of fun.

While channel 5 controls the flight mode, channel 6 switches on altitude hold and the weirdly named “carefree mode”. Engaging autohover is simple enough, just make sure you’re already hovering a bit, then flick the three-way switch to the center position. The copter will lock on to your current height with impressive accuracy as long as the ultrasonic sensor is used, which is for a few meters near ground.  Above that, the barometric sensor takes over. This sensor works quite well, but of course not as accurately as the sonar. It should be noted that altitude lock with the sonar sensor can only be attained over flat surfaces. Flying over a corn field usually results in too much scattering of the sonic pulses.

Quite frankly, altitude hold sounds like a really cool feature, but in practice it’s of limited value. This function is perhaps most useful for filming and similar activities where the pilot can’t concentrate on keeping altitude while flying.

Carefree mode is probably the most useless feature: It uses the built-in compass sensor to determine where you want to steer the craft regardless of its orientation. In essence, you can keep rotating around, and the elevator stick will always move the copter  away from you if you push it forward. It’s a cute gimmick, but certainly not good for getting beginners to learn to orient themselves.

FPV flight with the IFLY4 was smooth and felt very responsive. There’s the usual mushiness near ground due to the ground effect, but in general there is little you can do wrong in the fully stabilized mode. 3D mode still feels very natural and there’s no tipping tendency to be observed at high velocities. If you’re coming from a tricopter this will feel like a whole different animal. It’s all very predictable and indeed the thing you need to watch out for the most is the battery level, for time will fly just like the little quadcopter.

The 12A ESCs are okay for hovering and mild flying if you don’t have much payload on board, but we did experience a cutoff while carrying our FPV equipment and a GoPro Hero HD. The resulting crash from about 50 meters onto a gravel road broke a prop and cracked our FPV box, but the IFLY4 was completely unharmed. If nothing else, this is a testament to the rugged construction of this frame.

The aftermath of one of the ESCs cutting out: One prop broken, FPV box lightly broken, but the IFLY-4 frame is completely unharmed.

Max battery drain of all four motors was 40A, which is too much for most 1800mAh batteries, but a 3S 2650mAh Turnigy Nanotech was perfect for this quad: The takeoff weight was still relatively light and flight times of 7 minutes still leave plenty of juice left.

 

UPDATE: The Rabbit Controller, despite having been protected by the frame, did sustain some damage in that crash: Even though there are no visible signs of damage, the deceleration seems to have been rapid enough for some of the sensors to be damaged. As a result of the crash, the board would no longer initialize, showing an error with the Ultrasonic sensor. That was not the whole truth: We had to disable the Ultrasonic sensor, the barometric sensor AND the magnetic sensor to get the board to initialize and arm again. We also tried a firmware upgrade, with no effect. The rabbit still works fine without these sensors, although altitude hold and carefree mode are now gone.

Verdict

The Chinese have effectively killed the KK boards and their 8-bit clones with new 32-bit FreeFlight-Controller and the Rabbit. There’s simply no reason anymore to buy a 30+ dollar KK board when you get way better performance with the $50 FF-Controller. The Rabbit on the other hand is overpriced: $100 for the controller, $50 for the GPS addon. That’s a hefty sum for a product that uses community written open source code without giving back to the community or obeying the GPL license. And just think, the only thing they have to do to fix this is to offer a sourcecode download.

Make no mistake, the Rabbit Controller works flawlessly. It’s one of the better controllers out there, it has a bad manual and bad software but it works, and if you remember to set your throttle range to 110% on your transmitter you shouldn’t have problems getting this board to fly. But you have to decide for yourself whether an admittedly well-working altitude-hold, the silly “carefree mode” and a potentially worthwhile GPS option with return-to-home function is worth both $150 and the fact that you’re supporting a company that violates the GPL. Yes, it’s a chinese company, the land of the fake iPhones and all that – but come on, this is not a multimillion company they’re ripping off. It’s us, the community, that is damaged by this.

The frame itself and the sets offered by GoodLuckBuy are both great value. You get a full-fledged quadrotor for under $200 dollars (if you get the FF-Controller version instead of Rabbit) – for that kind of money microcopter.de will happily sell you half a frame or maybe their smallest controller board, a complete quadcopter comes to over $900, or 875 Euros at the time of writing.

The supplied 12A ESCs are underwhelming and you should consider replacing them. It’s ok to hover around with the standard ESCs but if you do FPV or carry some more payload, upgrade to 20 or 25A.  It’s not like the quad can’t handle the little extra weight.

Our verdict? Get the FF-Controller version of this copter and upgrade to beefier ESCs.  Or if you want to save even more, get the frame and controller separately, since the FF-Controller can be found for as low as $35 on the net. Not only will you get community-supported updates, but you’re also paying $40 less on the complete set while not supporting a company that violates a license that protects not the interests of megacorporations but of bedroom developers who work for free and for our benefit.

This gadget is a ton of fun. If you still have a self-built tricopter, this is your cheapest chance to jump to a drone with great flight performance. It’s a shame they tried to save a few more bucks on the ESCs than feasible.

 

Review addendum

After well over three weeks of flying this frame, we found it to be extremely crash resilient – the material absorbs even the most brutal impacts. There’s but one thing you have to be careful about when using the IFly4 frame: Make sure the props are properly balanced. This cannot be emphasized enough. If your props are unbalanced, the softness of the material tends cause resonance at certain rotor speeds. This will cause the copter to tilt over.
Also, the included props are too big. We found that smaller, lightweight 8×4 props work much better. With these props and a light payload the whole multicopter is much more stable and you can even keep the 12A ESCs, since smaller props equal less current.

The Rabbit Flight Controller might be a bit easier to get running (provided you still have Windows XP…), but the long term value of a MultiWii or comparable Open Source controller is greater. Once you are familiar with one MultiWii-compatible controller, you will be right at home with any upgraded model that might be released down the road. Our review unit of the Rabbit Controller doesn’t initialize the barometer nor the compass or sonar sensors after a crash, despite the board having been protected inside the frame.

The FreeFlight version of this set has been replaced with a Crius MultiWii SE by GoodLuckBuy. If you’re looking for a complete set, get that one 🙂

If you want the best hardware, get a Crius AIO Pro controller if you want full GPS waypoint functionality, or a cheap reliable KK 2.0 if you want the easiest possible setup. There’s really no reason for a Rabbit other than not knowing of the better alternatives.

 

Links

IdeaFly Company Website

IFLY-4 FF-Controller set on GoodLuckBuy

IFLY-4 Rabbit set on GoodLuckBuy

MultiWii Rabbit GPL violation warning

 

 

Tags: , , , ,

Category: Reviews

About the Author ()

FPVCentral is a private, independent news and review site for all things related to First Person View RC model flight. Covering everything from hobby, commercial and military drones, RC models and electronics related to FPV flight, we are not sponsored by any manufacturer or affiliated with any company or project.

Comments (16)

Trackback URL | Comments RSS Feed

  1. Randall Huston says:

    This probably won’t be posted as the article on the rabbit seems to be written by one of the MWii types in rcgroups, but I have to take exception of the portrayal of some of the “comments” in the thread that was alluded to in this piece.
    The attacks were started by the MWii crowd if you would be so kind as to read the entire thread. Rabbit purchasers were called “idiots” “thieves” “liars” “cheats” and basically every “nice” durogatory label you could pin on someone.
    Yes, the discussion got very heated. The thing that concerns me about the thread in rc groups is that the only person that has shown anything at all in regard to the “stolen code” is a person that has a dog in the hunt.
    http://abusemark.com/store/index.php?main_page=product_info&cPath=1&products_id=30
    This person also has the distinction of being one of the most abusive members in that entire forum. His snide remarks about new members are legendary. If you don’t believe me, go to rcgroups and look up the posts of a user by the name of “timecop”
    There is a solid core of “experts” in that particular part of rc groups that give the hobby a bad name. They basically try their best to make new members feel stupid and belittle “noobs” at every opportunity by saying “read the F-ing manual” more often than I care to count.
    Granted, I too, can be somewhat of a hothead but when someone is sitting their basically even questioning my heritage for expressing my views, I will defend myself. But on rcg, that gets you banned as several have found out.
    The funny thing is that the worst of the critics in the thread you mentioned, bought the Rabbit too, then resold them. If this was such a big issue, don’t you think they would have filed fraud charges with their respective credit cards? After all, don’t most companies protect you against counterfit merchandise?

    • fpvcentral says:

      Randall, FPVCentral is in no way, shape or form related to MultiWii or any of their contributors. I verified the claim made by them myself, using my own copy of IDA Pro (well actually the license belongs to $WORK, but anyway…)

      Calling people names is never ok. I can understand their frustration in that the response they got from the community was a shrug and a “don’t care”, which is not alright either. And if timecop’s motive was to discredit Rabbit in favor of his own controller, why are no such claims raised against FreeFlight or the other controllers out there?

      As for fraud charges: It just doesn’t work that way. This is basically a dispute about a license violation. You’d need to go to court, provide evidence of their usage of GPL code, wait for a verdict, etc. before you can even think about talking to your CC company. It’s not counterfeit until you get the legal system involved. Coming from a project that had a somewhat similar problem (a former contributor to a website project took the entire code when he was fired, and used huge parts of it, even those he did not write, to build his own site), I know that stopping such things is expensive, and if the other party is across the globe like in this case, it quickly becomes prohibitively expensive. We’re talking about a monetary risk of 10.000 to 50.000 for a small case like this one, more if it takes longer than a few months of course.
      To stop Rabbit from violating the GPL via traditional means, they’d have to put up that kind of money, up front, with no certainty of the outcome. This is China we’re talking about, and believe me, it doesn’t get much more legally challenging than this.

      Your credit card company won’t care about all this before there’s a verdict, or at least a court order.

      I’m not gonna get involved in personal fights of any nature. All I am saying is: Regardless of what the MultiWii team or Rabbit are saying, Rabbit’s GPS code is very much a port of the GPLed MultiWii code. And that alone is enough to require Rabbit to release their code under the GPL, no ifs and buts.

      • tgreening says:

        I think one of the key things you mentioned above was about getting a LEGAL ruling. Until such time as that happens it’s all He said / she said. For every person on rcg that is aware there are probably a bunch that will never set electronic foot on that site and won’t have a clue, and probably not even care about a fight between competitors they don’t know, and have no specific reason to believe.

        From my standpoint I have no real reason to believe you would be deceitful in this matter, but neither do I have any concrete reason to believe you are correct either. I believe there is at least one person over on rcg, who to a code idiot (me) sounds like he knows what he’s talking about, that says the multiwii camp could be wrong. Now. Who do I believe? You see the conundrum there I assume.

        This is why my stance promotes professional third party verification by disinterested parties vetted by the legal system.

        • fpvcentral says:

          The thing is, you can actually get a trial version of IDA Pro, open up the flashable firmware file from Rabbit, and check for yourself.

          A legal ruling is one thing, but it is highly unlikely that the similarities are the result of happenstance during a clean-room implementation. Two programmers don’t usually write functions the more or less exact same way.

          I went into this with an open mind, and frankly, the evidence is quite overwhelming and not impossible to verify for others.

          MultiWii doesn’t have the financial resources to get a legal ruling. And I guess that’s why this whole thing will never come to a satisfying conclusion.

  2. maggnum72 says:

    At the end of the day this is not a consumer issue, and members of RC groups have no right to accuse and call buyers of the rabbit boards names like thieves. As you say if they have an issue, then go through the right channels to get it sorted, and not carry on like a bunch of morons on a forum.
    I just purchased a rabbit.. why? Apart from needing another controller I purchased just to spite those multiwii morons on RC Groups who carried on and attacked consumers like Randall. You carry on like that then no one will support your cause. I certainly don’t. If you read this know this. While I understand your case, I don’t understand why you attack those who are not responsible for stealing the code. You have lowered yourself to a level where I say stuff you all. So I purchased a Rabbit, as I would rather give my money to the thieves then the morons. At least the thieves have honour.

    • fpvcentral says:

      We are talking about a GPL license violation. Not theft as such.

      A legal procedure in china is a very costly (and uncertain) affair. To my knowledge, it would be the first time anyone enforced the GPL in china.

      An open source project typically doesn’t have that kind of money.

      I don’t see where our review called purchasers of the Rabbit controller a thief or a moron or anything to that effect. If you purchase a rabbit controller, you are supporting a chinese company that violates the GPL. Whether or not you care about that, or anything related to the matter, is yours to decide.

      • maggnum72 says:

        I did not say you called anyone a moron on here. Please read what I said. The point is clear. While I see their point, that is the multiwii developers, the way they carried on on RC GROUPS thread about this subject, which clearly you have read, makes me say a bit F U if your going to carry on like that, and call those that have purchased a Rabbit, not aware of the violations names. Frankly, the proof that there is code theft is sketchy at best.
        There is currently a case where Apple is accusing Google of stealing code for the Android mobile operating system. Imaging if Apple called all Android users thieves? There would be out rage and Apple shares would drop. Same deal.
        End of the day, if you have your work stolen, firstly get definitive proof, secondly go about your complaint the correct way, and don’t go calling consumers of the product names on forums like RC GROUPS.
        Simple as that.

        • fpvcentral says:

          Quote: “You have lowered yourself to a level where I say stuff you all.”

          I assume you meant the MultiWii creators with that then?

          I completely agree that calling the buyers of the Rabbit controllers anything is not ok at all. Not arguing there.

          Seeing the proof requires a copy of IDA Pro, some basic assembly knowledge, and the flashable firmware file of Rabbit. I can confirm that the quoted code pasted on RCG is accurate, the translated C-code posted there is a fair translation and does a good job at highlighting the similiarities. There’s a lot of ways to handle the GPS serial data and while the outcome is usually the same, the code doing it usually looks very differently.

          So at the end of the day, the usual response to that proof seems to be along the lines of “I’m sure MultiWii got it from somewhere else too” – which is fair to ask in a question, but to date none of the people alleging this have produced any proof, or pointed to any existing project or piece of code.

          Of course you can choose to not believe MultiWii, and not believe me. My statement is that I verified that their basic claim is legit. Nothing more, nothing less.

          There’s one thing you should consider: Open Source developers who give their work away for free aren’t in for the money. This is a question of motivation. And I can’t imagine anything more demotivating than having my license violated and used without credit, and at the same time people who benefited from that work being in denial or outright opposition.

          The tone may have been escalated by both sides, but that doesn’t change the facts here.

          There’s no debate about whether Rabbit uses MultiWii code in violation of the GPL License. They do, whether individual users believe it or not.

          And again, the “proper channels” to deal with this would mean paying to the tune of tens of thousands of dollars to get an international IP law firm involved. Obviously that’s not something open source developers who do this kind of thing for free can afford.

          They’re currently trying to get this up on the gplviolations site, but they are extremely slow updating their page (their last update was sometime 2011…)

  3. Randall Huston says:

    The thing is that although this board might indead be in violation of some license, it’s only been brought up once it started outselling boards that are in fact, sold by members in that thread. Otherwise it was not even a concern. If you will read the thread in it’s entirety, there are even some concerns about other manufacturers but they have zeroed in on this one in particular.
    What bothers me and a lot of other people is the pompous attitude of the “experts” in that particular forum and how they are allowed to badger, harrass, and impune the integrity of anyone that disagrees with them. The moderators have allowed this situation to fester to the point that the entire website is losing credibility and people are being banned for merely disagreeing. In the end we all lose.

    • fpvcentral says:

      The actions of individual users are one thing, but that wasn’t the the objective of this article.

      Right now the discussions on RCG are at a standstill, with one half waiting for Rabbit to show any form of reaction, the other half denying the evidence, or not caring at all.

      What you have to realize is that were it not for the work of the MultiWii guys, Rabbit would not exist.

      As for the RCG forums, frankly I don’t use such forums anymore for exactly that reason. There’s simply too much noise.

      I have an engineering and computer science background, and there was a time when I fought a battle to make people realize that the XtremePower XPS 2.4GHz v1 and v2 system were inherently unsafe and had several critical design flaws, both in their lack of frequency agility and antenna design.

      Back then I learned a simple thing the hard way: You can have a degree in engineering and have studied transmitter and antenna design for years, but your qualifications don’t count for anything on a discussion forum. You can bring up logical arguments, cite the relevant literature, but people on the other side of the arguing fence don’t care. Why would they even care to read up on what “-10db” actually means, when they can just ignore the facts?

      And when someone on RCG posts that he/she “still hasn’t seen any evidence” then that’s the same ignorance at work here.

      It’s a big mistake to get into a fight with such people, or anyone on the internet for that matter – There’s only a discussion going on as long as both sides haven’t set their opinions in stone.

      I’ve seen the links where there was concern about other vendors. On one hand there’s absolutely zero information about anything there, just the finger that points somewhere – on the other hand, since when do multiple cases of injustice justify each other?

      The thing the MultiWii guys will have to try to do is to get the word out what Rabbit is doing, so at least customers have a chance to know what they’re buying.

  4. Scott Berfield says:

    One thing to mention aside from all the legal stuff is that the review is inaccurate in one way: the software runs fine on Win7. It sucks, but it runs. You most likey will need to register a component, but info on how to do that is freely available on RCGroups.

  5. paddy says:

    ummm…. had a quick look at the comments… talk about heated.

    ….so…. for someone who hasn’t flown an rc or built jackshit is this a good fly4 a good place to starT?

    any advice appreciated..

Leave a Reply