Friday, August 29, 2008

INO Lab HG-D760MG review

A while back, one of the local hobby shops in my area started carrying these Ino-Lab servos from Korea. While they are neither very fast nor really torquey(like those JR 8717 on 7.4v), they are still pretty decent and at the very least, still compares well to the current "decent" digital servos like the Futaba BLS451/BLS252 servos and the Hi-tec 69XX/79XX series. The best part is that it only cost half of what the Futaba BLS series and JR8715/8915, the 8717 for non-US market, are going for.






Packaging


No suprise, no disappoint. The servo came in a plastic box like how futaba servos are. The standard hardwares like rubber grommets, eyelets and servo horns and wheel are included. One small complain though. While the servo wheel was fine, the servo horns that came with it were a bit softer than those on hitec's and futaba's. Not a biggie, because the Ino Lab servos are using the futaba spline, so futaba horns will work good for these.




Specs/Performance


So lets take a look at the spec..



On 4.8v, this thing is faster than a BLS451 and has similar torque, which means that on paper, this servo is exceptionally well priced. BUT...obviously, anyone with experience with servos will know that specs are just specs. There are other things that matters too, for instance the deadband.

There is no technical measurement of the deadband for this servo online that I can found, but pushing these using my hands shows that these definately have a much narrower deadband than the hitec 6965HB that I have been using for quite a while. On the hitec 6965HB, a slight push will move the servo arm off its center by a wee bit, whereas on these, it takes quite a bit more force to move the servo arm, which boils down to better precision.

I am currently running these in my Align T-Rex 700N for cyclic and so far have only had 8 flights on these. Since I haven't run anything else on my Align T-Re700N before, I can't really say if its good or bad relative to the other servos around, but I absolutely don't feel any problem with regards to precision and centering.




The 760MG mounted on the 700N.


When I first got the servos, it was hard to turn by hand (obviously w/o power), which was unlike most of the other coreless digital servos that I have used. Most coreless servos should be turn with little resistance when rotated by hand, unlike these. After a few flights, it seems either the servo gears have bed in or something else have been "run in" coz now the servo feels a lot lighter to turn by hand.

The spec shows the weight at 51.3g, which is light for something of this spec and running metal gears. Full of doubt, I went to weigh this thing...and indeed, it did tip the scale at 52g.

I made a short video of how these servos behave on the bench. Since I don't run any stepdown on my heli, I left my regulator at 5.0v.



From the video (on 5.0v), its obvious that while these servos are not blazing fast @0.11s, they should still be more than quick enough for most pilots, especially so on 6v(0.09s). And in all honesty, even at 5.0v, my fingers are still the limiting factor in speed.


What I don't like about the Ino-Lab HG-D760MG servos...


As with all things in life, nothing is perfect. There are 3 things I don't like about these.
1. The servo horns(like what a online friend told me) are a bit soft. I am not sure if they will compromise flight precision, but so far I haven't really seen the need to change them.
2. Its not heatsinked. The plastic casing on the servo does get slightly warm if I "crack" the servo for over a minute on the bench. While I am not a "crack" flyer, I would think this servo will benefit from the addition of a heatsink casing.
3. The servo wire joint on the PCB is not gooped. This is the part that I don't understand. Why create a decently good servo for a heli and leave the wire joints at the PCB bare and abused by vibration? I hot glued mine with just a generic hot glue gun and stick. IMHO, this is something that should have been done at the factory.

Consumption
I have been told by a fellow flyer that these draw quite a lot of amp because he isn't getting quite as many flights as his JR servos on the same pack of battery. After flying some 3D with these servos, I think their amp draw is still pretty average and definately acceptable. I use 200mah on the 700N for a 7mins basic 3D, which equates to about 1.7amp. Pretty low for a 90size, I feel.

Note: This is part of a review I posted on rcheliresource.com

No comments :