redtail

My Feedback: (15)

Ok guys, need your help again. I had a friend of mine tell me that the nose gear steering servo should be analog and not digital because the digital servo would be constantly hunting for its center unlike the analog servo. Which type of servo should I use? Second, seen here on the site. someone said the servo should be very strong, around 300 oz of torque. Is that kind of torque necessary for steering? Thanks guys for the next bit of help. Chic

FenderBean

I would not worry about this most newer digital servos don't have any issues with holding a center. People used to say hitec servo hunted but I never had a problem with them. I use hitecs in my giant planes and futaba in my jets all digital minus the occasional small analog for a air valve operation.

Thud_Driver

My Feedback: (1)

I use both. Probably want metal gears more than anything else, but I use plastic too. Anywhere from 50 oz to 200 oz but I prefer something in the range of 100 oz. Lot of inexpensive metal gear ~200 oz digitals out there around $35. Tower TS-150 for one, Airtronics 94851 (on sale). Both actually the same servo, except the Tower has a Futaba arm.

I always use 60-80 lb test braided metal fishing leader for the wires (if it is wires). Anything less usually breaks after awhile (at least for me).

Flash has a DS8231: plastic digital @ 113 oz
Viper has a 94851: MG digital @ 192 oz
Velox has a 94162Z: MG analog @ 135 oz
L-39 has a Hitec 5625: MG digital @ 131 oz
the old TopCat has a Hitec HS605BB: plastic @ 94 oz)
etc.

Use what you have, change it if it doesn't work so well.

joeflyer

My Feedback: (48)

It doesn't take much torque to turn a wheel so 300 oz. is a bit ridiculous. It depends on the application, but 40 - 100 oz. should be sufficient. I don't see any advantage to using a digital servo, either analog or digital will work. It boils down to personal preference. A steering servo can take a beating, so a standard size servo with metal gears would be best.

Joe

mikes68charger

My Feedback: (34)

If digital don't use HS5645. They burn up mine did on the nose of my Rookie.

Savox makes a great 222oz. . SC-0251 analog for $40

Len Todd

A Programmable Digital servo's deadband can be programmed to stop any hunting. They don't hunt unless you have the deadband set to 1. Even then, I have never seen one actually moving. They just chatter/buzz a bit w/o damaging the servo.

The torque necessary depends on weight on the tire, size of the tire and length of the servo and steering arms. But having metal gears is a good recommendation. Also programmable servos have torque limits that can be programmed below the max spec of the servo. Kind of a servo saver setting. Ever seen a nose wheel that did not turn when the jet was sitting still on the ground and the stick was moved? If yes, that servo was stalled. W/o having the torque limit set below the max spec, the servo can fry.

Also, mixing the steering to the gear switch so that the servo is not enabled unless the gear is down can prevent the servo from being stalled when it is retracted and bumping up against fuse as it tries to turn.

mikes68charger

My Feedback: (34)

I like to put the nose gear in a separate channel and use a different trim button than for the rudders

FenderBean

+1 Jets dont seem to have much rudder authority on the first part of the take off run

mikes68charger

My Feedback: (34)

Well I like it because it let's you trim the nose wheel so the jet will track stight with out messing with the rudders in flight

Also the Rookie is slightly narrow gear and if you have the nose wheel with to much deflection it can cause you to hit a wing

redtail

My Feedback: (15)

Sorry again guys, I am a jet rookie, I am building a DV8R not the Rookie. But the ideas are great and helpful and I will use the idea of the nose wheel trim button. Thanks much. Great ideas. Chic

Bumble.bee78

My Feedback: (11)

Guys I am building a Rookie II. Do any one use gyros for the dual axis thrust tube.....is it necessary. Also I am thinking of using the canards as speed brakes. Or should i use the airbrake under belly?