Written by Ashley Davis Tuesday, 25 August 2009 22:35
|InoLab HG-D751MG digital servo|
Ino-Lab HG-D751MG digital servo review.
The T-Rex 700 is a 90 sized machine and with the larger blade forces and control systems it requires a suitably powerful servo for the cyclics. Along with that for some of today's new moves such as 'crack' you need a reasonably fast servo as well. There are various high cost options on the market such as the JR 8717. My focus in this review is to look at a lower cost option and see whether for much less money you can get close to the same performance.
The servo on review here is the Ino-Lab HG-D751MG. It's a metal geared servo with a speed at 6V of 0.11 for 60 degrees of horn movement. Relatively fast although you can find faster options. Having said that it is more than fast enough to perform crack and any of today's latest 3D moves. It boast a full 13.3kg/cm of torque which is more than enough by far for a 90 sized machine. The servos come with a water and oil tight seal, so running them on a nitro is not an issue (unlike some of the JR servos, 8900G to name one, which aren't warranted for nitro use as they don't have oil seals). You can also see a decent sized bearing on the main gear output shaft and also an additional oil seal to stop any unwanted oil coming in through the servo output shaft hole in the servo case.
So, we know it's pretty fast and very powerful, the next question is whether it is accurate. I put this to test using a swashplate leveler. The idea was that I would move the swashplate through various offsets of elevator, aileron and pitch and then see if the servos returned to a perfect center. I also looked at the ability for the swashplate to hold position when subjected to a load trying to pull it off position. In this regard I wasn't just impressed with the Ino-Labs I was actually quite surprised, they are extremely accurate and on a par with some of the best servos I've seen costing a lot more.
Below is a quick overview video showing the speed of the servos and to a lesser extent the centering. It's not easy to show the accuracy by way of video but I've had a go. I'm not keen on these bash the sticks and watch the servos go nuts videos but until I come up with a better way........
As always the proof is in the flying. In this regard I have also been extremely happy with my purchase. So much so that I've now bought the Ino-Lab HG-D760HB servos to go into my T-Rex 600 and I will also be doing a review of those for trextuning. I've also had a couple of other pilots try out my 700N to get a feel for the servos and the feedback has been very positive and mostly surprised given their price.