|Dimensions:||18 x 18 x 8mm|
|Operating Voltage:||4.8 - 8.4v|
|Operating Modes:||AVCS (or heading lock) and rate|
|Servos:||All 760us, 960us and 1520us digital tail servos|
|Frame Rate:||250Hz, 333Hz and 560Hz|
|Manufacturer:||Shenzhen Feichao Technology Co., Ltd., Guangdong, China|
I seem to recall having once started a review with the phrase, "timing is everything."
In this case, the phrase applies perfectly.
A failing gyro and a failing cyclic servo conspired to put the hurt on my E-flite Blade 400 on takeoff, resulting in only the fourth crash I'd ever experienced with it. I didn't know the gyro was going out until I got the model back together.
Manny Torres, a professional R/C heli pilot who's assisted me with helicopter-related reviews in the past, couldn't even get the thing to fly right.
It was only a day or two later and with great pleasure that I accepted the responsibility to review the Hobbymate HB790 MEMS gyro from Target Hobby, capable of both AVCS (or "angular velocity control system") and rate control.
I was faced with a decision: Should I Install the HB790 on a now-discontinued model (albeit with a Hitec HS-5065MG tail servo) or install it on the HK 450TT Pro I reviewed in 2011?
The decision was rather simple. The 450TT Pro is a clone of the magnificent Align T-Rex 450 Pro and flies beautifully thanks to Manny's perfect setup. Problem: The HK401 gyro used in the all-HobbyKing review was not quite up to the task of hard 3D and aerobatics according to Manny and another friend who happens to be a sponsored pilot with a major battery manufacturer. It's fine for sport or scale flying, but both friends feared the possibility of a tail blowout under extreme manuevers.
My guess was that the HB790 - which clearly appears to be a clone of a Quark Spartan gyro - would work far better. If the rather active and positive discussion here on RCGroups is any indication, it will. The discussion thread can be found here.
Get those refreshments ready and read on!
Gyros, seemingly as a rule, come lightly accessorized. Still, it comes with the following:
I'd like to share a backstory with you, if you'll be kind enough to indulge me for a few paragraphs.
Although the GoTeck 9257 tail servo in the 450TT works well and is a clone of the Futaba 9257, I originally wanted to put a name-brand servo out back. That led me to contact Suzanne Lepine of Hitec RCD in Poway, California. Suzanne not only offered Hitec's HS-5084MG metal-geared digital tail servo, she also offered a trio of HS-5065MG cyclic servos!
The 5084 is smaller than the 9257 the TT and the Pro are designed for. A discussion thread here on RCGroups told of an inexpensive carbon fiber adapter plate by Tarot RC. A quick internet search turned up Tarot-RC-heli.com of San Diego, California, right next to Poway.
Dave Frederick is the owner of the site and is Tarot RC's new exclusive US distributor. He got back to me by phone within five minutes of a phone message I left for him. Dave was beyond enthusiastic and sent me the adapter via Priority Mail.
Trouble was, the adapter's opening was too small and milling it out with a Dremel resulted in a servo whose mounting tabs wouldn't clear the hold-down bolts. Rounding the servo's mounting tabs didn't help, leaving me with a servo with a needlessly modified case before it had even had power applied to it.
Dave and I discussed the possiblity of having Tarot machine a mount to accept the 5084, but they declined. One of my friends, the one who flies for the battery manufacturer, recommended against using the standard tail boom mounts found on a belt-driven 450 because of possible balance issues, so it was back to using the original tail servo. I saw no real point in changing the cyclic servos without the tail servo since those Turnigy metal-geared servos work well.
Suzanne was beyond gracious and told me that I could keep the servos for a future review. Not only that, she'd sent me a defective 5084 from their "junk drawer" that I could cannibalize for its top cover of the case! Dave has promised a new Tarot helicopter in upcoming weeks, so stay tuned for a review of these fine products so generously provided by two of the greatest distributors in the hobby biz.
That said, installing the HB790 is like installing any gyro. Hobbymate provides two 3M double-sided tape squares and an aluminum mounting plate for use in high vibration applications.
I'd never experienced vibration problems with the HK401, so I simply used one of the tape squares to mount the unit and set about reassembling the 450TT Pro with its new gyro.
One thing is certain: The smaller, metal-cased HB790 is a far more elegant looking unit than the HK401, giving the 450TT a more upscale look. As for the HK401, it's found a new home aboard the Blade 400.
The proof, of course, is in the flying. Time to get this gyro programmed and airborne.
If one is flying a 450 Pro, or in my case, a clone, the default settings work perfectly with the either the real or the cloned 9257 tail servo. It's virtually plug and fly and seems to have been designed and programmed with this rather popular servo and application in mind.
Otherwise, all one really needs is the somewhat poorly written instruction sheet and some small tool with which to depress the HB790's program access button. It took me several repeated readings to figure out what it was trying to say, but actually doing the programming clarified the instructions.
Basic initial setup is pretty simple; it's only a matter of connecting the gyro to the receiver (but not to the servo), making sure all the transmitter trims and sub-trims are zeroed out and then connecting the servo once the gyro finishes initializing. Entering the programming mode seemed to be kind of hit-and-miss. If the system was powered up for too long before the programming button were pressed, it didn't want to enter the program mode at all.
Again, the defaults were all perfect for my application which saved a lot of frustration.
Servo modulation is next; once more, the default to the 1520 microsecond/333Hz modulation proved to be the correct one for the GoTeck 9257.
Direction and end point settings are next. In this mode, the rudder stick is used to determine direction and end points.
Once everything is set, the gyro will automatically initialize on subsequent flights. Easy enough.
I should point out that the default operating mode is AVCS as evidenced by the LED glowing blue. For those wishing to fly in what Hobbymate refers to as the "classic" rate mode, the transmitter will need to be programmed with collective-to-tail rotor mixing, not to mention mechanically trimming the tail in lieu of electronic trimming. On the other hand, the AVCS mode is simply plug-and-play and, as I would soon discover, works perfectly without the need for complex mix settings.
Once the 450TT Pro was fired up for its first test flight, it was immediately apparent that the gain was set far too high; the tail wag was almost uncontrollable.
Greatly reducing the gain via the Airtronics SD6G radio I had the privilege of reviewing not long ago was a study in simplicity and after a few tries, I had that tail locked steady.
I was amazed at how much better the tail held, even in a test hover. In fact, I had no idea what I had been missing. Even the tail on my Blade 400 with its stock E-flite 110HL heading lock gyro always felt somewhat better than that of the 450TT.
Not any more. Hovering was now almost hands off, at least as far as the rudder was concerned.
A few easy flicks of the rudder stick were met by utterly bounce-free hold when the stick sprang back to neutral.
High desert winds postponed my fast forward test flying, but when the opportunity finally came to get out to the soccer field near where I work, I was even more amazed.
I've been comfortable with the 450TT since day one thanks to Manny Torres's peerless setup of the airframe. If anything, I was now even more comfortable.
Not only did the cloned 9257 servo seem to work faster, it did so with even greater accuracy. Fast forward flight with a few chandalles thrown in for good measure was, at least to my level of expertise, as fun and as accurate as one could hope. Since I now had a lot more vertical room to play with as opposed to the room at the end of my driveway, I took the 450TT up "two mistakes high" and proceeded to jam the rudder stick full right. The moment I let the stick spring back to neutral, that tail stopped immediately. I got the same results with full left rudder.
As happy as I was with the results, my initial goal was to get it in the hands of a 3D pilot. Since I was unable to upgrade the servos, the least I could do was to install a new set of Align carbon fiber blades and to snug up each and every bit of hardware.
In order to really make the test as accurate as possible, I added some new batteries into the mix since my 2200mAh packs were starting to show their age. An e-mail to Mark Grohe of 2DogRC.com out of Fayetteville, North Carolina not only netted me two suitable packs, but very special packs to boot.
Mark sent me a pair of Mad Dog 2200mAh 3S li-pos rated at a previously unheard-of 65C discharge rating. They are, quite naturally, designed for extreme current draw like that found on a helicopter and I've taken the liberty of doing a separate review on these magnificent, affordably priced batteries with their lifetime guarantee. Once I'd swapped out the E-flite EC3 conectors with Deans Ultra-Plugs with Mark's blessing, a test flight of the helicopter with the new gyro, blades and battery showed a tremendous difference in the 450TT. This was always a sweet flying machine, but now it was even sweeter, with a near simulator-like feel.
The really hard part at this point was resisting the temptation to simply fly the darn thing before I could get video.
Patience really is a virtue; I didn't think I had it in me since the 450TT now flew even better than before!
Sadly, it proved impossible to schedule both a 3D pilot and a videographer. This time around, my videographer would be George Muir, the videographer of the Coachella Valley Radio Control Club. This beautiful club, located in the extreme eastern end of California's Coachella Valley, has a fabulous combination helicopter pad, park flyer pad and U-control pad.
I have a lot of stick time on that 450TT; it's always been a great deal of fun to fly with no bad habits.
As mentioned, the combination of the Mad Dog battery and Align blades served to make for a better flying helicopter, but neither of those changes were as dramatic as that to the tail.
Gone was the slightly vague tail control and in its place was rock-solid control. At no time did the tail exhibit any indication of blowing out, even with sudden throttle application. No bounce, either. Coordinated turns were easier and far more accurate than before and even simply turning on the tail 180 degrees to head back in the other direction was easier than before.
If there were ever any doubt as to the importance of a good gyro adding to the overall stability and airworthiness of an R/C helicopter, this great little gyro should dispel it. I was so comfortable with the newfound control imparted by the HB790 that I even did a fast forward, low altitude pass across the helicopter pad just for fun.
I honestly didn't know what I'd been missing. I have to admit that I'm seriously considering another HB790 for the Blade 400!
Flying a CCPM helicopter is the most demanding discipline of the radio control hobby, one which takes patience to master. Success in learning comes in no small part to a helicopter with an easily controlled tail. Not only is the HB790 an excellent training aid both for its stability and ease of setup, it's the perfect way for a more experienced pilot to get a great deal of tail-holding accuracy without breaking one's hobby budget. So, yes: This is an excellent gyro for a beginner to use in the learning of R/C helicopter flight.
While time will tell whether or not the Hobbymate HB790 gyro will stand up under repeated use, my initial impression is that it's one of the truly great and all-too-rare bargains the hobby has to offer. In my case, the gyro turned out to be truly plug-and-play despite a slightly wonky instruction sheet. It's affordable, works great, is easy to install and genuinely upgraded my clone heli.
Two thumbs way, way up for this great little gyro. Again, the only caveat I have to offer is the use of an inexpensive cloned part in an expensive name-brand model, but for now, I am beyond satisfied with the HB790 and I'm certain anyone else will be as well. For only $39, it's light years ahead of the $10 mail-order gyro it replaced.
A great many thanks are in order, beginning with Chris Mulcahy. Chris, known here on RCGroups.com as "CSpaced," is also the editor-in-chief of RCG sister site Crackroll.com, a site dedicated to all things related to the fine hobby of R/C helicopter flight. Chris is the gentleman who arranged the review in the first place; there is no finer heli-related site on the internet and Chris is the reason why.
Some thanks almost beyond my ability to express them are San Diego-bound to both Suzanne Lepine of Hitec RCD and Dave Frederick of Tarot Helicopters. Although my plans to use their fine products to aid in this review didn't come about, their gracious and generous assistance is the epitome of class, professionalism and support. I urge our readers to support these two magnificent California companies as well.
Mark Grohe of 2DogRC.com was equally generous and gracious in sending a couple of his fantastic new Mad Dog 65C li-po packs. Those packs didn't so much as break a sweat even in the warm desert summer and are well worth the price. Forget those wimpy little 40C packs, friends; a Mad Dog is on the loose!
George Muir is the peerless videographer for the Coachella Valley Radio Control club and it shows in his fine, fine work. George was kind enough to take time out of a Sunday morning to shoot the video. I worked with George on a project I'd done for the AMA and I look forward to working with him again. Any visitor to the beautiful Palm Springs area who has an interest in model aviation simply has to set aside some time to visit this incredible AMA Gold Certified club.
Angela Haglund is the hard-working administrator who orchestrates these reviews and of course, our thousands of readers are why we work hard to bring you the literal ups and downs of model aviation products of all kinds.
Stop by often, bring the family and enjoy your stay here at RCGroups.com!
There's a lot to like where the HB790 is concerned:
Minuses are few:
|Jul 28, 2012, 07:12 PM|
Hmm...great timing. Thanks for the writeup. I have a HiTec HG-5000 gyro on the Beam and I just can't seem to get it to work right. No matter what I do - and yah, I've done what all the internet write-ups say.
Not even a 30 year veteran in the field can get it to work right for me, and he's keen enough as to be building his own flybarless system (hardware/software) to trump the "V". Go figure?
I still want to use the dedicated 5083 servo I had. Thankfully this little hobbymate can be used with it (i.e. 960 micro sec and 333hz).
For $39, why not. I tried to find a domestic stocker of this. Something call rchelicoptershops out of CA seems to sell it. I went ahead and ordered it online, but it seems like PP billing went to China. I guess we'll see, and I'll report here what happens.
Can't what to try it. Sounds like just what I need.
|Jul 28, 2012, 11:36 PM|
|Jul 31, 2012, 01:22 AM|
Friday Harbor, WA -San Juan Island
Joined Aug 2008
Great review, really appreciate all the info. I do, however, have a question. Not specifically for the gyro, but the GoTech 9257, and the settings used. I also have that servo, and HK had listed is as 1520us/ 80hz. I really struggled with this when setting up my GA-250, as there isn't a setting that goes that low. People were talking on here about burning "clone" 9257s with the wrong settings. I couldn't find anywhere else on the web that stated anything different than the 80Hz HK listed. So, what lead you to believe it was a 333Hz servo? Is it still working OK at this setting? Does it get hot when pushing the tail?
I realize this is a little off the topic of your review, but I would like to get a combo for the tail I can be confident in, rather than always waiting for the heli to start spinning out of control. And, to that end, this gyro might just be the ticket. Or, maybe I can just change my settings on the GA-250 to 1520us/333HZ and not worry about it anymore.
Thanks again for the detailed review, usually only see this kind of attention to products costing "thrice the price".
|Jul 31, 2012, 02:37 AM|
Since that servo is supposed to be a direct clone of the Futaba. I used the Futaba default setting. So far, so good.
My research tells me the 80Hz setting is for analog operation, but the gyro won't go that low.
Settings are 250, 333 and 560Hz depending on the servo with the majority of servos falling into the as-tested 1520us/333Hz setting.
The gyro works so well that I'm seriously considering the Futaba servo to go with it!
|Aug 01, 2012, 01:50 PM|
I got my HB790 gyro within three business days from www.rchelicoptershops.com in CA with free shipping. Everything made it safe and with all the accessories as mentioned (two Al plates- no steel - and one thick and one thin foam pad).
Servo choices are 1520/333, 760/560, 1520/250 and 960/333.
One thing I had to do is open up the harness a little so I could reach the servo and Rx...not a problem.
The case is metal (nice), but appears to be riveted together or something.
Will install shortly and test.
|Aug 01, 2012, 08:07 PM|
I had a minor mishap with mine which had nothing to do with the gyro and I took the time to re-enter the programming mode and to double-check the end point settings while I had things apart. The trick is to press and hold the little button on the gyro within a couple of seconds after it initializes.
|Aug 01, 2012, 08:28 PM|
Agreed. If you wait too long, then you can't get into the parameter menu that accesses compensation direction and travel endpoints.
My quick initial findings are that it's works much better than the HG-5000 that it replaces. There is not a whole lot of adjustment options, but I think it's set pretty good as is. There is mention of a data link for the gyro but nothing more.
The stops are firm without bounce, and I don't notice any drifting. I'm getting a little occasional wag, but I think I will use a better mounting option and turn down my CC Ice governor gain. The servo is a little warm (running at 5V too and not 4.8V), but again I think that will go away with the wag. Will work on it more when I get a chance.
|Aug 02, 2012, 01:12 PM|
Had a little more play time. I don't know if it's the Beam vibes, my linkage, servo or what, but I get an intermittent tail wag. Thought it was the gov gain but now seems like gyro gain. Had to drop gyro all the way to 25 (on the Futaba scale) to get the wag to stop.
Still seems to work great though with just the slightest hint of drift. Out in the field, this new gyro instilled more confidence than the former and really shines in FFF too. Only when really pushed with extreme manuvers does my setup protest with the occasional tail kick (perhaps gain too low).
More on the manual; there seems to be a misprint and lists 5083 servo twice...the first should read 5084. Also in gyro configuration menu, it does not say, but a push of the button is needed to go from step 1 to step 2.
In summary, for $39, as far as the gyro is concerned, I call it a great success and I have no need to look any further for my little daily flyer. I do however got a MKS DS95i servo on order to see if there will be any difference. This servo is more than I wanted to spend, but I will report soon.
|Aug 13, 2012, 08:18 PM|
Well, I tried the new upgraded premium servo (760/560) & running everything at 6V now. Still can't get the tail wag to stop even in a simple hover unless gain is turned down again to around 20-25% AVCS. But unlike the prior servo, the tail does not seem to lose composure during rapid pitch pumps. So for lack of any bad habits, I'm staying with this. As mentioned, it's a great improvement and good enough.
|Aug 17, 2012, 01:12 PM|
Got some more flying in. The Hobbymate gyro still works great.
But still bugged on why I could not go up in gain more than 18% as I would get a funky intermittent wag. I would like to increase gain to help with any blow-out I might get with rapid maneuvers.
I tried different gyros, mounting pads, tail servos, governor gains, arm radius, belt tension, linkage play, etc. I even flipped the grips around to drive blades on the trailing edge. Nothing was getting rid of my Beam E4 (450) tail wag.
The culprit could be a soft Aluminum tail boom. It's of the modulus that's just about right to cause a harmonic in the tail at about 2800 - even with main blades off, the flexing is visible.
To add injury, the horiz stab mount is plastic and the boom braces are quite anemic and offer non-existent side-to-side support.
Gonna order some KDE braces, with a Align CF boom, new CF blades and metal mount. Will see if it fits and also makes a difference in flight. .
|Aug 31, 2012, 06:39 PM|
Well, in this final post, I was able to increase gain from 18 to 28 by firming up the tail end. The Align CF boom, metal stab mount, and Fusuno neon Trex 450 fins work perfect on the Beam. Also the KDE boom braces are crazy strong. And lastly the EcoPower CF tail blades.
The new tail blades don't do anything about the wag, but they do help over stock with blowout associated with running a lower gain.
Overall I like the HB790 Gyro, and for scale and gentle 3D it's fine. But whenever a stong hold is needed under the most extreme moves, there is a compromise between holding and wagging which is gain dependent...well at least as far as the Beam E4 is concerned.
|Sep 04, 2012, 09:35 PM|
Glad you like it.
I've been having a lot of fun continuing to fly my 450TT Pro with this gyro. Only things I've had to do were to relocate the tail rotor pushrod on the servo since it was off by a spline and to fine tune the gain a bit. I flew it the other day after a minor repair and all is fine.
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