The Hirobo XRB Lama is a weird addition to my flying collection of nuts and bolts since I dislike electric choppers. The XRB, a twin rotor Co-Axial helicopter, has two counter-rotating rotor discs. There is no torque which needs to be acted upon by a tail rotor system. Rudder inputs are created by varying the speed of one rotor faster or slower, adding torque into the system and causing the body of the heli to rotate left or right.
Model Hirobo Teathered XRB
Engine Two small electric motors powered through an 'umbilical' cord
Main Rotor 2 x 2 Light Weight Stryofoam blades, 350mm Diameter
Tail Rotor Non-driven, decorative
Airframe Dimensions 355mm long x 165mm Tall
Radio Equipment Tethered Remote Control powered by a power supply block similar to a laptop power supply
I bought this heli on a whim from my local hobby shop (www.3d-rc.com) and have had a lot of fun with it despite it's small size and limited capabilities. I have spent many hours on it just hovering around and practicing flight orientatin such as nose in and side on. Like most electrics it can be quite a handful at times as the slightest gust of wind can blow it off course.

The teather on this helicopter can become a bit annoying at times. If you fly out beyond the length of the cable, it will pull the heli into the ground, so it's good to keep an eye on things and make sure you're not flying beyond your means. (Which is pretty common with this hobby, but usally financially!)

The 4 rotor blades are a very light foam molded into shape and blade roots attached. They are relatively cheap to buy in sets which is good because they are easily damaged by standard helicopter mishaps around the house. Unlike a big heli in an open field, you find a lot more things to hit with these small heli's in the house.

The Hirobo XRB is a nice heli but you have to take some time to get used to it. It is very difficult to control while you are in ground effect, but once you get a couple of feet into the air it clears up and is much more stable. You may find that the tail likes to twist around on you a bit. It will scare you at first, but once you get used to correcting for it, it's not too bad. As the motors warm up the will become less efficient and reduce the rotor speed, this will also cause the tail to swing around. Minor adjustments to rudder trim can correct for this for the most part. If it becomes controllable, your motors are just too hot and you need to take a break and let them cool down.
I've flown this heli for 20-30 minutes at a time depending on how the motors are holding out. That's plenty of time to get your fix in if you are trapped indoors. And just in case it's not, let it cool down and fire it up again for another flight.

The controls as set at the original defaults were not sensitive enough for me so I moved the balls on the flybar to the alternate location. In the original configuration I felt as if the heli was lagging behind my control inputs. After flying bigger helis I'm used to an almost immediate response so a very soft control didn't work out too well for me.

All in all this is probably the most stress-free fun I've had with any micro electric heli I have owned. The tether is a bit annoying, but I will gladly accept it since I don't have to charge any li-polys in order to fly it or really do much maintenance other than replace a blade or two on occasion. The price is a little steep at a bit above $200, but I've gotten my $200 of fun out of it, and my nose in with my big heli's is doing pretty good now!

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