BOBCAT servo's question?
 

Please tell me what others have used. I have tentatively elected to use these Futaba servos in my Bobcat.

9550. in stab
9151 in wing
9202 nose-wheel , is this the right choice. Has any one had problems of wobble in the nose gear. Do they need to be metal geared?

Another problem is that Futaba doesn't make a mini sized or medium sized digital for the rudder . BVM suggests digital mini or medium sized high torque digital servo. What servo did people who use Futaba put in in place of
JR in the rudder booms?

I was told by Futaba that their gyros will not work with JR. What have you guys used? Does the futaba gyro work with JR?

Mark L
Baltimore

BOBCAT servo's question?
 

Why not use a JR gyro? the 460T seems to be popular.

I have used Futaba gyro's and governors with JR radio's with zero ill effects.

BOBCAT servo's question?
 

This is what I am using in mine:
Elevators - JR 3301's
Rudders - JR 3011's
Ailerons - JR 4721's
Nosewheel - JR standard ball bearing (don't remember the #)
Retracts - JR 321
Brakes - JR 517

I am using a Futaba GYA-350 gyro with the goofy heading hold function turned off.

BOBCAT servo's question?
 

The reason I am using the Futabas products in that I use a 9C Transmitter. And a 9 channel PCM reciever.

Do you know if you can use a Futaba Gyro witha Futaba reciever?

BOBCAT servo's question?
 

Why wouldn't you be able to ???

The gyro number I listed above is incorrect (bad memory), I am using the GYA-350 in mine (with a JR receiver).

Here is a link to the instructions for it (in .pdf format): http://www.futaba-rc.com/manuals/gya350-manual.pdf

You should be able to find the info you are looking for there.

BOBCAT servo's question?
 

Kevin,

I screwwed up on the message.

Futaba gyro with JR servos.

Mark

BOBCAT servo's question?
 

I've had 18 flight in three weeks on my Bobcat using a Futaba gyro and JR servos without a problem.
This combination is working great for me.

BOBCAT servo's question?
 

Thanks,
Mark

BOBCAT servo's question?
 

Hi Guys;

Just finished with the installation of my new Bobcat XL and this is what I am using:

Ailerons are 8411
Rudders are 9411
Elevators are 3301 (9411 will not fit, and on my next BobCat I will NOT cut the elevators in half and try to use ONE 8411)

Rudders are linked to a 460T gyro
Elevators are linked to a JR Matchbox for fine adjustment.

Steering is 9411
The retracts and the brake are being controlled by electronic valves.

BOBCAT servo's question?
 

If you use one 8411 servo on ONE elevator you have abandoned all of your pitch control redundancy.
BRG, David Gladwin

Re: BOBCAT servo's question?
 

Hi Kevin

Is that the 401? I thought the 9462 was a servo?

I want to try that 401 cause I have one (my heli stuff is collecting dust) but I want to turn that feature off, and only run one channel....I wonder if that will work.


Hate to run a gyro without a way of turning it off :-(

BobCat Servos
 

Mark,
Many flyers are using JR servbos with Futaba receivers with great results.

Here's the servos that I'm using in my BobCat XL:

Elevators (2) JR DS9411 They do fit....
Rudders (2) JR DS9411 82 in oz.
Nosewheel JR 4131 93 in oz.
Ailerons (2) JR DS8411 155 in oz.
Retract valve JR 351 enough torque for the job
Brakes JR 351 ditto
Gyro JR 450 no longer available, use JR 460

The JR 9411's require that you notch a corner from the PolyPly servo cover so the servo case can hang out a little. You can't see the case corner in flight, and there isn't any technical reason why that isn't okay. You can see it, but it is on the bottom.
The additional torque and metal gear train of the DS9411 makes a big difference. (82 in oz vs. 60 in oz.)

An 8411 on the elevator(s) is much larger than a DS9411. It has bags of torque, but it would be much more difficult to install, and offers no redundancy.


The two elevators, either of which is redundant in the event of a failure, could make the difference between having an airplane or having a smoking hole. I hope none of us make use of the redundant surface and servo, provides but since it's there, why not look upon it as insurance?

I realize that this didn't answer the entire question exactly, but is intended to be food for thought......This is my choice, and it works for me. 157 flights so far on my BobCat XL. I swapped out the JR DS3421's (rudders and elevators) for the JR DS9411's after 43 flights. One of them failed on the ground; drove hard over, melted the case, and fried the extension harnesses. Glad it happened during taxi back to the pits after a flight!!!


Good luck with your servo choice.

Harley Condra
BVM REP

BOBCAT servo's question?
 

Ah Grasshopper, you did not read ahead to my next post!!! :D

I was just guessing at the part# and I was posting while I needed to be doing about 5 other things at work today. I screwed up!

My Futaba gyro is a GYA-350, and they do not actually call it a "heading hold" gyro. They instead gave it the cryptic name of "AVCS" (which as best as I can tell means "automatic vector control system"). The AVCS turns on anytime the gain is switched over 40% positive of center on the switching channel, so it take a little programming work to keep this feature from coming on at all. In effect I am not be able to use the upper 30% of the gyros gain since all of that part of the gain is linked with AVCS, but I don't think the Bobcat would have wanted that much gain anyway.

This is only the second gyro I have ever owned, and the first Futaba gyro so I am not sure if the 401 could be used or not.

Re: BobCat Servos
 

Harley, was that a rudder servo on a gyro? Just wondering

BOBCAT servo's question?
 

My Bobcat has around 250 flights on it with the following

8411's on ailerons
3301's on elevators
9411's on rudders
460t gyro (Started with a 450 it died, then 2 460's third one was/is a charm) Run the gyro at 10% with gear up and about 60% gear down and you will have a solid airplane. I leave the knob active on the gyro gain so that I can crank it up a little in windy conditions.

BTW the P-120 on it is still running strong with ZERO problems.

JR DS3421 failure
 

John,
Yup, sure was.
I posted all of the facts at that time.
The DS9411's are up to the job. They work fine with the gyro.



Harley Condra
BVM REP

BOBCAT servo's question?
 

Hi Mark!

I have JR-Servos in my newest Jet, but they do not work with my futaba PCM-reciever. Lucky that I have a futaba Fc-28 and a JR PCM-10x.

Use futaba or hitec and you have no prob.

David

BOBCAT servo's question?
 

David,

I am planning to use futaba 9551 the flat digitals in the stab, and 9151 in the wings. I have ordered JT 9411 medium sized digitals for the rudders.

Do you know if the JR Digitals will work with a 9 channel PCM rec from Futtaba , and will the futaba gyro work with the JR rudder servos/nosewheel.

Thanks,
Mark

Elevatro redundancy on a bobcat
 

The bobcat will NOT fly on one elevator half. Trust me I know. If you want a redundant system, just use the two servos but do not separate the elevator into two halves. The bobcat I am building now will be using JR 8411's or Hitec 5945's. In the event of a failure one servo will drive the entire elevator without a problem.

As far as the original question. JR Servos will work with futaba gear. I "used" all JR servos in my last bobcat with a JR G450 gyro with a R149dp receiver and a 309DPS synthesized receiver without a problem. Tranmitter was a 9Z


Patrick.

BOBCAT servo's question?
 

Thanks Pat,

Have you used The hytec digitals.

Mark

BOBCAT servo's question?
 

Hi Mark!

I use JR8411 with futaba without a problem. But for example the 4421, 4041, 4021, 4621 do not! I didn't try other servos, because I can switch to a proper radio gear, depending on which servo I use.....

And it is very scarring if you turn on your tx and your rx and all servos run wild. Moving the sticks will stop them, but will you fly with such a system?

BOBCAT servo's question?
 

Thanks for the info.

Im am finishing my first jet. I remain nervous about my wisdom of using JR 9411 and Futaba 9202 for the nosewheel steering and the rudders with a Futaba Gyro. Toni Stillman from radio South has said that I should not have a problem. Futaba has been totally non helpful. They say that they will not work together......

I appreciate the note

Mark Lamos

Hitec Digitals
 

Mark,
I am currently using the 5945 on the elevons of my hotspot and have used them on the steering and braking/throttle servo on my inferno 1/8 gas car. the 5945 in the inferno is still going strong after after about 6 months of constant abuse.

Patrick.

Half an elevator
 

Sirrom,
I think that I would still rather have one elevator half working instead of one servo trying to overpower another one.
In the event one of the servos were to drive to one end, yes the other half/other servo would be in big trouble. A crash would most likely result. But, in the event that the dead servo stayed in the "trail position", or close to it, the other half should be capable of landing the airplane.
Please explain how you know that one elevator half will not fly the airplane. Did you lose one servo and experience a crash?
Please explain that one to all of us.

Harley Condra
BVM REP
Servo killer
harness fryer

Bobcat Crash
 

Harley,
Yes, I lost one servo in the elevator which caused a crash. I know for sure that it was the elevator because when the plane crashed it was in a rather marshy are and it buried it self in the ground about 2 fee nose first. fortunately the tail section of the airplane was un damaged which resulted in being able to trace the problem. I was able to remove the elevator and rudder servos from the aircraft. The rudder servos are perfectly fine and so is one elevator servo, the other servo had it's gears stripped out. I had control over all the surfaces except pitch when it went in. After salvaging the servos from the wreckage I plugged them all into a receiver and found that one elevator servo was indeed stripped. So I had only one elevator servo working when it crashed. Also, in my case the surface had no resistance from the servo since it was stripped and was just flapping in the breeze and not locked in one position. That elevator was a bad design.