Aastan

My Feedback: (28)

What's the deal with the TowerPro MG995 Servos? I see some talk in the RC Car forums of people using them in Monster Trucks. Are they suitable for RC Aircraft? The specs are below:

Dimensions: 1.57" x 0.79" x 1.44" (40 x 20 x 36.5mm)
Weight: 1.78oz (48g)

Operating Speed (4.8V no load) : 0.17sec / 60 degrees
Operating Speed (6.0V no load) : 0.13sec / 60 degrees

Stall Torque (4.8V): (13kg/cm) (180oz/in.)
Stall Torque (6.0V): (15kg/cm) (208oz/in.)

Temperature Range: -30 to +60 Degree C
Dead Band Width: 4usec

XJet

I wrote a review of these a while back.

Plus side:
* all metal gears -- pertty tough
* cheap (and I mean "cheap")
* seem to have good torque and are moderately fast

Negative side:
* very poor match between electronics and mechanics produces bad overshoot
* feedback pots simply don't last -- resulting in lots of jittering around neutral
* gear-mesh, centering and stability highly variable from one unit to another

In summary, if you get a good one they're okay and will work (for a while). Chances are you won't get a good one though and you'll notice that they rock back and forth around neutral, overshoot past the commanded position and generally have poor resolution.

I bought 14 of these servos and here are the stats so far:

1 was pretty good and is still in service after about 6 months, although the feedback pot is now so worn that I'll be removing it because it shakes like it has the DTs.

1 failed within 5 minutes of installation -- and almost brought a plane down with it -- the output arm just gyrated wildly for about 30 seconds -- then it came right. Hasn't faulted again but I'm not about to risk it.

4 have not been accurate or stable enough to merit using on any aircraft I value

2 were stripped and I used the servo amps to replace those in a pair of Hitec HS425BB standard servos. This makes a *very* nice little digital servo that is fast, accurate and has great holding power. The difference between these modified HS425s and the original MG995s from which the amps were pilfered shows just how bad the MG995's pot and geartrain really are.

The rest are sitting under my bench. Maybe I'll build an RC doorstop one day and they'll be just perfect for that :-)

Bottom-line: They're okay but they're really cheap and risky.

Aastan

My Feedback: (28)

XJet,

Thanks for the info. I was planning on placing some 5645MG's in my 1/3 scale Cessna when I came across those. I couldn't believe the the reported torque for the price. I think they are not worth trying for the first time in my $3500 plane. Thanks again.

JoeVen

I´m very sorry to read that, but is the truth[&o][&o]
I put a couple to drive the two halves stabilizer of my Christen Eagle by a "Y" harnes and one of them moves erraticaly just when I imput the rudder stick!
I think the jittering around neutral won´t be a problem, but half stabilizer moving when is not commanded really is...
Is there any DIY work to fix it?

PopPhil

My Feedback: (8)

Hi all, just got 4 of them MG995. After reading about them I took them apart there was junk loose( dirt ?) in the gears, cleaned up and they were smooth. The pots are OK, but the case where the pots go is not right causing the pot to tilt sideways when the holding screw is tighten, and this puts a bind on the the pot gear,and gear train as well. The pot in this bind wears very quickly and goes byby. I've got all four working great except for the overshoot, but thats the gear set up. Looks like they took alittle from everybodys servos to build them. They should work OK in the RC cars.
Pop Phil



Its hard to go up when your out of fuel, but coming down is OK?

Patto

I took a gamble and ordered some of these servos recently, just to see mainly how they would perform. Well, two of them had a ridiculous amount of overshoot. Basically, I gave full stick deflection, the servo responded past the point and went back a little bit. I installed it as one elevator half and put a Futaba 3010 on the other half. The 3010 is about the same price, for info. The Towerpro made a constant digital humming noise, even when not attached to the control surface. I hooked up the elevators and found that the 3010 moved just as fast as the Towerpro 995MG, using a 6V battery, even though Towerpro's specs. say the 995's are significantly faster. The overshoot issue was just ridiculous.

I found that all four of the servos I ordered had the same characteristics to some degree.

I'll be returning mine. I don't know if other cheap servos are as faulty as these ones, but I don't recommend anyone buy these!!

XJet

Toldyaso :-)

It seems that I've bought a lot of stuff recently that represents "new product" on the market. Some is good, some is really bad.

As a result of my experiences (and to help others), I"m going to set up a website with my reviews on it. I'm not about to plug the URL here (since it could be seen as competition for RCU) but I'll put the word out through other vectors when it's ready.

Patto

I don't think RCU would be concerned about it. I say post the URL when it's ready and if they ask you to remove it, you do so, but I don't think it will be an issue.

I wish I had read your review of the Towerpro servos before purchase. I just can't believe that someone makes those and sells themas being in functioning order. The whole line is defective as far as I can tell.

XJet

When I review something, I call a spade a spade (and a lemon a lemon).

I've been writing reviews of all kinds of things for magazines for a couple of decades now and I've had a few that were rejected for being too honest. These were usually when the publisher was also receiving large amounts of advertising from the manufacturer/distributor of the product.

I've also noticed that most reviewers are just so happy to get a review sample for free that they feel obligated to say nice things in their review -- I don't.

The other problem with reviews in magazines or on websites like RCU is that the reviews are performed by different people every time. This means it's hard to tell whether someone likes or dislikes something simply because of personal preference or for very valid reasons.

For example, I've seen 3D models reviewed by people who clearly don't know a waterfall from a blender. These people often say that the heavy, underpowered, brick they're testing is "a great 3D ship". If you then get a very 3D-capable flyer reviewing a plane that's 10 times better but not perfect, they might say "this plane has some deficiencies for serious 3D fliers". Based on these reviews (with their widely different but not apparent perspectives) people might be tempted to think the first plane is better -- but it isn't.

For this reason, I'm hoping that by documenting my own levels of experience, interest and preference up-front and then having those same factors affecting *everything* I review, the results will be far more consistent and therefore more valuable to readers.

I've also got a sophisticated setup for testing servos (resolution, speed, torque, damping, etc) , receivers (sensitivity, noise-rejection, selectivity, cross-mod/intermod rejection, etc) and other bits of gear we use every day.

Also, because I won't be soliciting advertising, there'll be no pressure to write only nice things -- although the good stuff will be praised.

Right now I'm also working on a FAQ covering the perennials such as: PCM vs PPM/FM, digital versus analog servos, 2-stroke versus 4-stroke, nitro versus electric, what are transmitter modes?, etc, etc.

Patto

XJet,

I think you may have a winner of an idea, and maybe you will be able to get some advertisers on your site at some point. Hey, there's nothing wrong with letting them pay you to advertise to your readers, just as long as you don't let who's paying how much affect your objectivity.

I say roll with it. It sounds like a website I would want to visit frequently.

-Pat

dominiquecockers

My Feedback: (971)

The manufacture claims they "ARE NOT" for air use, and are to be used on the ground, the distance the plane goes, leaves to much interference

XJet

I've never seen such a claim -- where did you come across it?

Gunner

My Feedback: (4)

Interesting. just about every add for these say they are suitable for R/C planes!!!

Scarey...

Patto

Yeah, I've never seen anything about them not being approved for air use by the manufacturer, but I would agree with that idea 100%. I don't think the part about airplanes going too far away creating extra interference has any technical merit. The receiver would be affected by such distance, and thus the servos would be affected, but any servo would be. These servos just plain suck, and I would not use them in a car or truck either, not unless you want to have a constant over-steering problem...

asmund

Me and a friend have stocked up on these as we thought they were a great scoop( are you paying lots of $ for servos, suckers? [8D]). Well after reading this thread on them we hooked some up for a quick test, and ohh my god, what did we find out? when moving the stick on the radio fast, back and fourth between max travel, the servos just didn`t react at all, they just froze. when doing the same with the cheapest of hitec standard servos they actually coped with that. Even when moving the sticks slowly the 995 and 945 servos sometimes took a timeout. I guess I wount fly these servos afterall and I think they will also be crap in my buggy as those servos really work hard from right to left/ brake to full power, fast and vigorously. Stuff can be TOO cheap sometimes

XJet

I've been searching high and low (and wasting lots of $) trying to find the best standard servo and the best hi-torque metal-geared servo on the market.

I ruled out the MG995 *very* early on in the piece but have tested a lot more since then.

I'll be publishing the results of those tests (and many others) on my new website pretty soon. I figure that others might as well benefit from my experiences and save themselves some money :-)

I'm also testing receivers, engines, popular ARFs, etc.

Various suppliers will also be ranked on their pricing, performance, after-sales support, etc.

Patto

Looking forward to that website, Xjet.

-Pat

thisoneused

My Feedback: (-1)

JUNK SERVOS!!!!!!!!!!!!!!!!!!!!!!!!!!!
Dont buy them!!!!!!!!!!!!!!!!!!!!!!!!!!!
I did before I read these threads,,,,what a mistake!!!!!!!!!!
Absolutely awful!!!!!!![:'(]

remcl1

My Feedback: (3)

I was just about to order these servos. Thanks for the info and saving me time and money.

xjet you ever get that website done? I think the Bro's would be interested in it as well.

Hiaboo

i believe I do have a couple of those BUT they are USED I got them forlike $5 (the pair) and I've been using them in my boat and 1/10th scale truck, havent had issues, they're fine for those, I believe but as for something as delicate as an aircraft, FORGET IT!

Why the heck would you put a $15 chinamart servo in a $500 plane, come on, give me a break.

XJet

I got sidetracked for a while with work but have been working my butt off the past week or so to get it up. Check it towards the end of next week (if all goes to plan).

remcl1

My Feedback: (3)

After getting the down low, I did not. I went with Hitec.

Hiaboo

(just saying that for everybody's benefit -- that thought just doesnt really occur to everybody)

Patto

I went with Hitec as well. Although, it looks like Hobbico is selling Hitec servos with the Hobbico name for quite a bit less through Tower Hobbies now. Same specs and same case... That may be an okay time to go with the cheaper servo. But, I agree, why risk an expensive airplane with those Towerpro servos... I almost did, and I'm also glad I went with Hitec.

dominiquecockers

My Feedback: (971)

I'm sorry your right, at one point a supplier had said not to use them in planes, after this quote I have had a new supplier and they also claim to be suitable for air use, so I must change my stand on them. I have the Hextronik HX12K's