Hitec 31055S HS-55 Economy Sub Micro Universal Servo

Good little servo at a fair price from a trusted company.

This is a light weight replacement for my ailerons and so far it has been performing as advertised (about 8-9 flights at about 10 minutes a piece) and so far the only problem I have had is the constant buzzing coming from the servo. As far as I know I have it set a factory center but it continues to buzz as though it is under a load. It hasn't gotten hot yet or even warm so I'm assuming it is OK but the noise leads me to believe it is receiving I signal from something and may be receiving an input signal from something as well. I am using an AS3X stabilizer receiver so it may be telling it something it shouldn't while the plane is sitting still. Anyway, 3 stars because its doing its job so far and I will update review if I figure out the buzzing noise is not the servos fault! UPDATE as of 21 Jan 2015. I received a comment from another user of this product that said the reason for the buzz is the fact that I am using an analog servo with an AS3X receiver and I should be using a digital servo instead. This should explain the buzzing noise. I am also upgrading rating to 5 stars since I now have an additional 20 flights (all successful) with this servo and no problems. I hope this helps out. If something should go wrong I will update with any info as to why and what happened. Until then, if anyone has any warnings about using analog vs. digital with my particular receiver pleas chime in and let me know!

EDIT!I have left these sit in my models and didn't use them for about a year. About 15 out of 30 no longer work! They jitter and shake like crazy near center. It is probably a little corrosion on the potentiometer but there is nothing visible. Hitec quoted me at nearly $8/each to repair. I needed one for a college project and had one sent to me via prime. But the brand new one had the same jitter problem as the other ones using a completely different circuit. The funny thing is, all of my China servos including four I found in a crashed model airplane wing in the desert work great. The better thing is that Hitec uses all proprietary components. As an electrical engineering student, I can NOT find a replacement pot on mouser, jameco, or digikey. My honest advice is to steer clear of these, they were once a 5 star product back in the 2000's but these can't compete with $3 China servos.

I use a lot of the HS-55 Hitec servo's as well as a bunch of other models and brands. I have had a lot of good luck with these servos,and they are very reliable for me and they are reasonably priced. I don't care much for the HS-81 as I have had to replace the gear train in two of them recently. (they were new)I have never had to do so with the HS-55's. I started RC in 1960 and have used lots of radio's and servos in my time so I recon I can gripe once in awhile huh? Over all, this is a great hobby and the equipment is better than ever, and more reliable then ever before. Hitec is a good outfit over all in my book. Good luck to you all, HALF FLAPS.

I purchased two of these servos to add flaps to my T-28 trojan. When I received them I thought no way these will be strong enough to hold the flaps into position during fast flight. I was mistaken, WOW excellent performance and they weigh almost nothing! Great quality and value, thank you amazon! The only reason I gave it 4 stars instead of 5 is because I would have liked the flaps to travel a little further to get more range of motion out of them. But they extend pretty far as is.

I bought this servo for a project I am working on. I needed a small servo and this one fit the bill just right. I am not using it in an airplane but I do RC airplanes also so I have an idea of how they do.This one works well, has good strength and responds well. One of the tests of a servo is how many thousands of cycles it will run before problems or failure and I don't know how many cycles this will run but it looks to me like a solid little unit at a good price.I bought a driver to drive this servo and the two work well together  EMO1003 Servo Driver

These servos were smaller than I thought they would be, but that was my fault so it is no mark against the product. The 1 star was docked because of this reason. The servo tends to twitch at the full range, so the actual full, useable rotation is less than the physical rotation. Which was no problem for me. But could cause problems for people who depend on the full range of motion.

Love these little rascals! Work great with my old futaba J system