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

700N build issues

First off, some build issues that I faced with the 700N...

1. The rubber grommet hole on my canopy was drilled unequal and too rearward of both sides.
This resulted in having one side of the canopy bulging in the middle and touching the main gear when mounted on.



Instead of redrilling, I added spacer to the canopy mounting post. This solves the problem. Notice the different spacer thickness because of misaligned mounting holes.






2. Page 22 Linkage rod D
The length in the instruction manual was a little too short for the swash to be level. I had to increase mine by about 3mm. Some say they had to increase theirs by up to 5mm, so YMMV.


3. Ball Links do not go onto the rod straight.
A handful (a big handful) of my push rods do no go into ball links straight. The problem I am facing is that I can start out really straight but once it get tight, it just goes crocked.



4. Tail fin being slanted when tail case is fully tightened.
I had already read about this on the Align forum in Chance's build thread. I have the same issue too. Spacers will help to solve the problem, but I am just lazy to take it out now.

I suppose this is because of the tail case clamp closing up when tightened down.


5. Fuel Line hole on the main frame.
I am using a YS 91SR and when mounted on, the regulator will touch the fuel line IF I use the upper hole on the main frame. Using the lower one seems to solve it.


6. I am not usually that picky, but since this is my new heli, I hope it looks and stays clean for a while. Unforunately the white gears are already getting really dirty just after 4flights.


7. CF Rod reinforcement for the Rudder control rod
Either the metal rod is too big or the cf sleeve is too tiny. There was no such problem in the pre-production or the first batch kit, but on the second batch, the metal rod took a lot of effort to screw in, whereas on the older kits, it just slip in in a matter of seconds. Took me 15mins or more to get mine in. Its the CF rod at the bottom of the photo. I tried running without the CF sleeve but there seems to be too much flexing and vibration on the metal rod even at idle, definately a place where metal fatigue will take effect. This CF sleeve is a must.


On a more positive note, my kit came with a very thin shim for the main shaft and that one fits PERFECT on the main shaft. All problem that I have, except for the ball links/linkage rods issues, were pretty minor and easily resolved. Align seems to have also improve the quality of their tail blades. The one that my friends had on their 600N were hollow, the 700N ones appears to be solid and filled-I know because my tail blade got ding..

Mounting a governor sensor on the 700N

The T-rex 700N uses a pair of clutch bell mounted magnets for the governor sensor instead of the usual fan mounted magnets. It will be fine if you are running the Align governor included in the box, but if like me, you opted for another governor, you will need a bit of mod to fit the governor sensor in. This mod will work for governors like Throttle Jockey Series, ATG, GV-1 and a whole bunch of others.

All you need is

1x 30/50size sensor mount(do take note that some 50sizers are actually using the 90size sensor mount, we need a real 30/50 one.)
1x Small saw
1x sensor
Some shrink wraps and cable tie.
Some C.A, i.e superglue

1. Prepare/Cut the bracket to size.


Cut the 30/50 governor sensor mount as shown above. The black one on top is a un-cut standard 30/50 mount. The one below is what you should end up with after cutting. It should be around the region of 26mm, give or take an mm or two. It is suppose to be a little shorter than the one on the G-600 because on the Align governor, the sensor goes THROUGH the mount, whereas on our generic mounts, the sensor goes ON the mount which increases the length of the final assembly.

It doesn't have to be a exact, on the dot kind of cut because there is a little bit of room for adjustment when the sensor is mounted on the main frame.

2. Attaching the sensor to the bracket.


Bend the sensor gently to form a 90 degrees arc. I am not very sure if all sensors are directional, but on mine, only the side with the wordings work for my magnet. So check yours before bending as you will want the side of the sensor that works to face the magnet.

Attach the sensor to the bracket and shrink wrap the sensor to the bracket as shown in the photo above.

C.A. the sensor tip to the bracket as in the photo. Thick C.A. tends to work better here. The key here is to apply in thin layers. Its going to take a while to dry and solidify, but don't blow at it coz you only end up making the the C.A. run.

Cable tie the wire at the shrink wrapped area. Cable tie on none-shrink wrap area might cut through the wires. I had forgot about the cable ties on mine, but it seems to be working well so far.

3. Mounting the bracket onto the main frame.[download id="null"]


I highly/strongly/definately recommend that the sensor assembly be mounted before putting the frame halfs together. Spacer was required on mine to space the sensor away from the main frame to that it is hanging directly above the magnet on the clutch bell. The photo is a bit dark and blur, but for those who are wondering, the spacer goes between the bracket and the included governor mount(pg10 of manual). You will need to source for self tapping screws to mount the sensor assembly. Adjust the height of the sensor by "dry fitting" the clutch bell assembly on the frame.