Appropriate servo for airframe
 

I've posted before my intention to scratch build an F3A in about a 90 four cycle size airframe. I thought I'd get an opinion form this group as well as on the other site,

I'm struggling a bit picking servos to use for that airframe. I've never used digital servos before so might give them a try. It is my impression that a digital servo has better holding power than an analog servo. Does that mean I can reduce the torque "slightly" using a digital?

In any case I was thinking elevator and rudder (single servo each) should be somewhere in the 70 to 90 oz range, the ailerons around 40to 50 oz range. The throttle can be about anything small or smallerhttp://static.rcgroups.com/forums/im...lies/smile.gif

What would be a recommendation of a good bang for the buck servo for this application?


Thanks!

Ken

Ken,

look up Savox servos for good bang for the buck.

OK. I looked at some Air tropics servos. One was 136 oz @$30 and the other was 56 oz @ $17. Both rated@6 volts.

Ken

Damm spell check on my phone. .... Airtronics servos.

Ken,

If you like Futaba servos and want to go digital, you may want to look at the S3152's. At 6.0 V, they may be exactly what you're looking for. I'm assuming that, even though you mentioned a 90 sized four cycle sized airframe, that means you're sticking a glow motor in it. If you're electrifying it, you'll have a lot less vibration which is what really prematurely hurts the servos. A nice full list can be found at http://www.futabarc.com/servos/digital.html with all the specs you may need.

Scott

These are the specs on the Airtronics servos I'm looking at/considering. My only question is if they are a dual ball bearing or single. I'm guessing single from the price.

Rudder/elevator.. $30 each "standard size"
Airtronics 94846 High Torque BB Digital Servo • Gear Type: Metal Gear
• Motor Type: 3-Pole
• Weight: 51
• Speed (s/60d):
• 4.8V: 0.23
• 6.0V: 0.2
• Torque oz-in
• 4.8V: 107
• 6.0V: 136


For the Ailerons $17 each "mini size"
Airtronics 94813 Micro 18gDigital Metal Gear Servo
Specifications
• Metal Gear
• Motor Type: 3 Pole
• Weight: 19
• Speed (s/60d):
• 4.8V: 0.19
• 6.0V: 0.16
• Torque oz-in
• 4.8V: 50
• 6.0V: 54

Ken,

Look at this Airtronics servo for elevator & rudder. Has a nylon gear train and should be good for a 90 size plane. I ran these on elevator with a Symphony with YS for years. Price is good too. [h=2]Airtronics 94835 Hi-Torque Nylon Gear, BB Digital Servo[/h]maustin