dave Lucas

Have any of you Chaps out there had any problems with using Futaba 9151 Coreless Digital Servo`s on 6 volt . I would like to know before I commit .

ricksheau

My Feedback: (1)

i have had no problems with Futaba period exept for cases breaking in crashes Futaba is a great maker of Servos exspecialy when you can get them cheaper than usaual at Servo Central call them and they will hook u up

dave Lucas

Thany you for that . Do you power them on 6 Volt ?
Dave Lucas

Gone to a Higher Plane

Futaba does not recommend the 9151 on 6 volts..only 4.8...
See the link below...

http://www2.towerhobbies.com/cgi-bin...?&I=LXVZ37&P=7

didiwatt

My Feedback: (38)

Dave:
Before you spend the big bucks for these servo's, check out the thread I send to Futaba under the manufacturers forum. I had 9151's all around on a DP Edge with a DA-50. Had one on each airleron which should have been plenty on a 15lb aircraft. On first flight, airlerons fluttered and stripped both servo's. I have narrowed it down to the servo's not having a strong enough gears. Used 9206 servo's before on same set up with no problem but I wanted to try digitals. Why would they put plastic gears on a 130oz digital servo?

LOL
Paul

dave Lucas

Thank you for that Info . I have them fitted all round on a ZN Line
Extra 330s 2.5 Meter . I was surprised to see they are plastic gears in these servos . I will try them and see .
Dave Lucas

didiwatt

My Feedback: (38)

Dave:
Just make sure you double them up on the airlerons and I think you will be OK. Took my servo's in question out and gear #3 and #4 (counting the pinion on the motor as #1 and counting out) were stripped on both servo's. One had the pinion completely blown away.
Paul

3D Joy

I think these servos are designed for pattern airplanes which weight a maximum of 11 lbs. The only way to be really precise is with nylon gears.

Shortman

My Feedback: (21)

Nylon gears are the most precise gears and like 3d joy stated the Futaba 9151s are pretty much "pattern servos"... just about everyone at the Pattern Nats used them besides JR guys..

also, if you think those gears are cheap think again, Futaba has the most expensive gear sets out there and if i recall are nearly $50 for a set!!!!!!

dave Lucas

Thanks for that . I have doubled them up on the ailerons . So it should be good .

matlok

I called the Futaba service center a while back with this same 6v question and basically they said it's ok on all their digitals except the heli ones (sorry don't remember the number(s) - I think it's just the one that comes w/the high end gyro) but it has to be a regulated 6v; i.e. a pack w/regulator to output no more than 6v.

As far as the gear issue, I've wondered the same thing. I had a 9151 on rudder on a 29% Edge, and stripped it in the air during a blender. Landed the plane ok, but it really does make you wonder why such a strong servo would utilize all nylon gears. The s9350 or s9451 seem to make more sense.

didiwatt

My Feedback: (38)

Dave:
Let me know how it goes with the servo's. How much does your plane weight? What engine do you have on it? I plan on repairing my plane and doubling up on the airleron servo's. Only because I cannot return the servo's to Great Planes because I soldered on extension 20 guage wires. Hopefully, I will be OK.

The reason I chose these servos was because Chip Hyde used them on his 40% Ultimate at TOC. At lease that is what the equipement list in RCM said. I figured if there were good enough for a 40+lb airplane, they would be good enough for a 15lb Edge.
WRONG

Have not heard back from Futaba yet. Will be interesting what they say. I just wish they would make a digital servo comparable to the JR8411. Futaba is way behind in servo technology.

Paul

Shortman

My Feedback: (21)

i to have said that, but there coming out with a new line of servos that hopefully will be comparible to JR and Hitecs line

matlok

[QUOTE]
[Futaba is way behind in servo technology.
QUOTE]

IMHO I respectfully disagree. In 13+ years I've never had any problems whatsoever with any Futaba servo, the only exception being stripping a 9151 in flight (which I do agree is pretty stupid, putting nylon gears on a 130oz servo - I just don't understand that) Otherwise they have been flawless. Always center tight, never strip, from the el cheapo S148 all the way up through the digitals. I've heard, seen, and experienced plenty of (two leading competetors') servos having problems; I think that's why they cost less in most cases. I counted ~45 different servos on their website, so selection isn't an issue. And I think the service is there too; I broke a mounting flange off a s9101 in a crash (the servo still worked flawlessly) and when I called about a replacement case they sent me one for free b/c they said the shipping would have cost me more than the part.

They may be pricey, but Futaba is definitely not "behind in servo technology".

didiwatt

My Feedback: (38)

Matlock:
Note that I did not complain about quality. I agree with you. This is the only time I have ever had a problem with a Futaba servo and I have over 50 of them, from 148's to this 9102. My favorite servo is the metal geared 9602 and they have been flawless for me on larger airplanes.

What I complain about is the lack of choice in digital servos. Especially since I tried to ask Bax if the 9102 would be adequate for my application. JR & Hitec have 2 to 3 times the choices.

If you note in Futaba's literature, the 9102 is rated for an FAI rudder application. Knowing the abuse a rudder gets, I figured they would be plenty adequate for airlerons on a 15lb airframe and plenty if you double up the servo's on a 1/3rd scale. I don't feel Futaba gives enough information on their digital servos to make an informed purchase.

In my case, it was a costly mistake. However, I will remain true to Futaba but reserve the right to complain about choice of gear train in this servo.

Paul

dave Lucas

pc eagon . The 9151`s I am using are being installed in ZN Line 97" Extra 330s . It will have a DA 100 upfront and I estimate it will come out at 21lb au weight . 2 x 9151 on Aelerons and 1 x on each Elevator 1/2 . I hope this does the trick
Dave Lucas

locoworks

i believe 6 volts on the servo's is ok. i think MATLOK will find that futaba say 4.8 volts for the heli servo's, usually refering to the so called tail servo's because just like JR the newer GYRO'S are only rated at 4.8 volts... as a mixed voltage system would be complicated , 4.8 volts is what they recommend so you can use their gyro's aswell as servo's on said helicopter. without a gyro in the system on your plane i'm confident 6 volts is ok.

didiwatt

My Feedback: (38)

Dave:
Thanks for the reply. Good luck on your new plane.
I have a Composit Arf Extra with a DA100 ready to put together and have 6 new 9151s. My ideal was the exact setup as yours.

However, now I am too concerned about the gear train and that is just to much money to risk it. Don't know what servo's to use now.

Keep me posted as to how your set-up works.
Paul Eagon

rajul

My Feedback: (58)

Is there a rule of thumb on what the max torque a nylon servo gear train can take ? Thx........

didiwatt

My Feedback: (38)

Rajul:
I am no engineer (maybe someone could chime in) but I don't think torque is the problem. I think it has to do with the amount of area in the airleron that you are trying to hold and keep from fluttering which is the natural tendency of an airleron. Mine stripped out not during a manuver but straight and level flight at 1/2 throttle and rich setting.

Seems to me that someone could come up with a formula based on the area involved you are trying to hold and then a formula on how much pressure a plastic gear can take. There are probably hundreds of different variables involved that I am stupid about.
Paul

rajul

My Feedback: (58)

Hi, reason I ask is bacause comments like "putting nylon gears on a 130oz servo is a bad idea" seem to suggest that there is a "rule of thumb" for how much it can take. Maybe the number is based on experience ?