|Main Rotor Diameter:||13.78 in (350mm)|
|Fuselage Length:||13.38 in (340mm)|
|Weight with Battery:||5.3 oz (150g)|
|Transmitter:||Futaba 4 channel FM (included)|
|Battery:||600 mAh 7.4V li-poly (included)|
|Available From:||Tower Hobbies|
In the early nineties a clever friend and I came up with the idea of designing a micro-heli. Except for some notes, a few drawings, and many late nights staring at a Stock Drive Products catalog, nothing ever came of the concept.
Luckily there are a lot of people in the world with more follow-through than we proved to have! R/C hobbyists are now enjoying the rewards of recent advances in R/C rotorcraft miniaturization. A decade of fervent tinkering by a few brave souls is paying off for the rest of us in the form of ready made helis powered by the newest generation of lithium-polymer batteries.
The Heli-Max RotoFly is a new entry in the ready-to-fly micro helicopter market. Proven ground has been tread here, as the RotoFly shares many features in common with it's competitors, including a fixed pitch head, integrated gyro/esc control board, and a separate motor for the tail.
While the RotoFly might not break new ground in features, it delivers in a big way in the price, availability, and convenience departments. At the time of this writing, the Ready-To-Fly (no, I mean Really-Ready-To-Fly) RotoFly lists for $279.99 US at Tower Hobbies.
The RotoFly comes nicely packaged with a fully assembled heli, charger, battery pack, manual, stickers, instructional DVD, training gear, and radio.
The radio is a simple Futaba 4 channel unit without any frills. The owner must supply 8 "AA" batteries to power the radio.
The training gear is taped to the bottom of the styrofoam insert. Make sure you don't throw the packaging away without lifting the styrofoam insert out of the box and turning it over!
For that matter you should just keep the box as it doubles nicely as a carrying case.
There really isn't anything to assemble! The owner can simply put batteries in the transmitter, charge up the included lithium polymer battery pack using the included charger, wait a bit for the charge to complete, and go fly.
These steps are well covered by the instruction manual so I won't bore you with them here.
It's a good idea to go over the heli before the maiden flight. The only adjustment my heli needed was the flybar paddles, which weren't aligned properly with the rest of the rotor head.
I took to the street in front of my house for the first flight. I live on the side of a forested hill at the foot of Oregon's coastal mountain range so it is a nice secluded area for a test flight of a micro heli.
The RotoFly's electronics calibrate themselves when the battery is first connected so it is important to plug it in while the the heli is resting on the ground. I always get a little bit nervous when I plug in a micro heli for the first time because in the "old days" of electric R/C there weren't a lot of safety features. I'm happy to report that the RotoFly has behaved very nicely when I've connected the battery, with not even the slightest glitch.
Unfortunately I had a bit of trouble with the first flights. The heli would wobble uncontrollably after a few seconds of hover.
A brief email exchange with the distributor cleared things up. The RotoFly's blades were attached very tightly when it arrived and I decided the blade retaining bolts needed loosening. This was a mistake! On the RotoFly the blade bolts should stay tight.
After getting that mistake straightened out the RotoFly hovered nicely. I was able to practice hovering from all angles and also do some simple pirouettes.
The training gear are attached and installed on the heli with a few minutes of effort. I didn't spend much time flying with them but did find them to be helpful in reducing the chance of a tip-over. Beginners should make use of every possible advantage when learning to fly helis so I highly recommend, if you are just starting out, that you make use of the training gear.
I took the RotoFly to the local flying field for some forward flight. While flying slowly forward worked ok, it turned out to be very difficult, almost impossible, to keep the heli in sustained forward flight at anything above a couple mph. I was able to do some slow circles and figure 8s but found that the RotoFly wanted to pitch backwards and responded sluggishly to corrections.
The RotoFly isn't alone in this area. A lot of micro helis have problems with forward flight. The usual fix is to stiffen the head a bit.
I decided to make a very simple head stiffener using spare parts from my shop so I rooted around for a spare servo arm that was large enough to span the distance between the blade retaining bolts.
Some spare bolts and nuts were used to attach it to the heli. I was able to put this together in about 15 minutes and the nice thing is that the entire modification is reversible if I decide later on that I don't want it.
The stiffener mod seems to improve the heli's responsiveness, possibly at the expense of stability. Immediately after making the stiffener modification I was able to fly circuits around trees and other obstacles in my front yard with no trouble. There is still a tendency to pitch up but it is now controllable with some "down elevator" command.
On the assumption that forward flight would be further improved with a more forward CG, I decided to try a larger battery pack. I put a Kokam 3S 700 mAh lithium polymer pack in place and enjoyed the additional power over the supplied 2S pack. I was a little concerned that the on-board electronics wouldn't like the extra voltage but everything seemed to perform fine. With the 3S pack I was able to gain altitude more rapidly and fly large circuits in the front yard, drawing the attention of my neighbor, who made a few comments about my childish endeavors with flying toys.
I think he was just jealous.
I don't know how long the tail motor and other components will last at this extra voltage level so try it at your own risk.
I found the RotoFly to be an excellent example of a fixed-pitch micro heli. The micro-heli community enjoys modifying helicopters, and I'm sure mods will be produced or adapted to fit the RotoFly, but I'm happy to report that it flies nicely out of the box. This is a refreshing change from the norm of a few years ago, when a micro-heli purchase would involve hours of fiddling and a hundred dollars or so in upgrade parts.
There are other micro-heli packages out there at slightly lower prices than the RotoFly but none of them, to my knowledge, offer a lithium polymer battery pack and charger, nor are they truly ready for flight out of the box the way the RotoFly is. So much is done for you that I was presented with an interesting dilemma: I had the heli for a couple of weeks and looked at it in the box without disturbing it at least half a dozen times trying to figure out what on earth I'd write about in this review.
Thoughtful touches like the training gear and instructional DVD will help newcomers feel more comfortable with their first flights. The RotoFly survives abuse reasonably well. When the inevitable mishap occurs, replacement parts are readily available. I see no reason why a heli newcomer shouldn't elect to do his primary heli training with a RotoFly in his own garage, living room, or front yard.
|Dec 24, 2004, 07:33 PM|
Electric Aircraft World
Joined Nov 2001
It's the smallest heli in ARF format and it is really RTF.
Small enough to fly well in small indoor spaces.
Comes with 6 ch rx.!
Lipo is bad, gives short flight times., unuseable.
Motor goes after 20 -30 flights, replacements are difficult.
|Dec 25, 2004, 02:47 PM|
I'm suprised by the "Stepping up the voltage" part of the article. Doesn't seem like a good idea safety wise to go with a higher voltage pack, unless the manufacturer recommends it.
|Dec 29, 2004, 03:07 PM|
i'm a long time r/c airplane pilot and first time heli. i'm following the instructional vid to a "T" and i'm about to actually lift the thing off the ground, but i read in the review that the fly bar needed adjustment. that scared me a bit....i don't know much about heli set up....what should i look for in the fly bar to make sure it's set up right? also, should i be concerned with CG or anything else i should check before first flight?
|Dec 30, 2004, 10:13 AM|
While I don't own this helicopter I think I can answer your questions. The paddles on the fly bar should be level and should stay level. If not they need to be adjusted to level positions and tightened. This can be done with a good view from the side and doesn't take any special equipment for aligning purposes. My helicopters either need an allen wrench or a phillips screwdriver to tighten the paddles.
The C/G is usually obtained by balancing the copter by holding the fly bar on both sides with it 90 degrees from the body of the copter (straight out the sides.) Some other micro helicopters never completely balance on the C/G but remain slightly tail heavy. In those cases a little forward trim on the right trim sticks forward/back trim tab corrects for that in the other models I have seen. Good luck with your Heli-Max! Mike
|Jan 03, 2005, 03:38 PM|
thanks Mike, that's very helpful. i have "flown" since my last post and i use the term loosly! i have noticed this though. it has a tendency to "wobble" in a circular motion when attempting to hover. is this a sign of anything, or just the nature of such a small heli?
|Jan 03, 2005, 05:31 PM|
I think a definative answer will have to come from someone else who has flown the Robomax as it is very light and small and it depends on how big a wobble it is and how frequently it occurs. I have found wobbles to sometimes be an indication that something is loose or a servo isn't working quite right. I like you don't like wobbles and try to find the cause but I admit I sometimes have trrouble finding the problem even with the copter right in front of me. Good Luck. (Not to bad a problem if you are able to sustain a controlled hover.) Mike
|Jan 03, 2005, 11:18 PM|
Check out my thread for some info on this little heli:
If you tighten up the blades, move the ends forward by .5"-1" or so, and keep them exactly even, you'll reduce that wobble by quite a bit. If you use Geoffrey109's spring kit with the stock blades, you'll get rid of wobbles and shakes for good. Here's the thread for that info:
And here are the kits:
Be careful how much weight you add though, because the stock motor has barely enough power to keep it in the air as it is.
|Dec 05, 2006, 10:08 PM|
Joined Dec 2006
Hi, I just tried to fly my new rotofly ex and it will do nothing else but skid to the left and turn to the right....no lift off yet! any adjustment suggestions? Thanks, James.
|Jun 15, 2007, 11:41 PM|
Joined Jun 2007
My experience has been negative. I find the Rotofly to be extremely inconsistent. Mine drifts sharply to the left and hovers tilted when I can hover it at all. After each landing the behavior changes, even if the landing wasn't particularly rough.
I couldn't fly this thing at all if I hadn't fashioned my own durable landing gear out of wooden dowels. The enclosed "training gear" was ruined the first time out. Without the dowels, I couldn't land it straight enough to avoid the blades hitting the ground. There is just no way to get this thing flying level.
Another complaint is that there are two metal bearings right underneath the main blades that tend to pop out anytime the blades strike anything. The blades themselves are very durable but I've lost two of the bearings and had to order extras.
I'm not an experienced helicopter pilot, but I was sure my skills were good enough that I could fly this thing without a lot of trouble. I pictured casually flying around my backyard and even using it to learn new maneuvers. I was wrong. The best I can do is 30 seconds of hovering once or twice on a battery pack. Most of my takeoffs are aborted because the helicopter starts sliding wildly to the left before it even takes off. I also had a lot of problems with the tail rotor losing control, although I was able to fix this by adjusting the gain on the electronics. (Which I had to figure out by reading it on a message board, there is no information about this in the manual that came with the Rotofly).
|Jun 17, 2007, 05:47 PM|
The smaller the heli the harder to fly, hover, land. It was not build with a lot of thought in mind, but once you read the rotofly threads and do some mods, it is quit the little flyer. I too had a hard time getting mine to fly right, but after reading the threads and moding, it flys like a champ.
|Jul 27, 2007, 10:51 AM|
So! I'm a fixin' to get one of these. I wish to play with making a triple-blade rotor from Aluminum on Haas CNC's & running 3 blades. Question: Is there any obvious reason this would not be a good thing? Any qualified input appreciated! Chris
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