What are Futaba Digital Servos you use for your Jets? Most of you are using JR and Hitech.I'm using Futaba system and thinking digital servos for my first turbine powered jet . Thanks in advance for your feed back
Richard

Don't rule out using JR servos with your Futaba system. I fly Futaba but would not use anything other than JR digitals on the main flying controls (although I do use a high torque Futaba on my Roo airbrake).

I can get JR servos cheaper than the equivalent spec Futaba servo and their quality seems to be fantastic. Although I have only had a few flights with my Roo so far, the 6 JR digis have all been faultless.

I did originally intend to use Futaba 9151s but then discovered that they were suffering failures in big pattern planes. I sold them, switched to JR and never looked back

Richard,

You can use JR servos with Futaba receiver. I have almost all JR servos in mine and Im flying with the 9Z. I do have a few futaba digitals in mine they are the 9252s on the bobcat ailerons. I know Futaba has a brochure out that has every servo they make in it along with all specs including dimensions, torque and gear type. I just picked mine up today from radiosouth. You might try and email them to get a copy.

Mike

I used the following digital servos on jets: S3050, S9350 and S9152. all of them worked very well on elevons, elevators, aleirons, flaps, speed brakes, etc. at non-regulated 6 volts.


In 25 years in r/c activities I never had a problem with a new futaba servo. can´t say the same
about other brands.. (and yes, I tried some of them)

Best regards, Enrique

has anyone used 3305s?
its not digi, but i wonder if they are
ok for jets. (smaller ones)

"I can get JR servos cheaper than the equivalent spec Futaba servo"

I used to think the same thing until yesterday. I needed some wing servos and I typically use the JR 3301. Saw Futaba now has an equivilent with the same torque for $60 vice the $89 for the JR.

I have had 3 jets - 2 SpiderJets F-16 which were slightly overpowered with Simjet 3000 and controlled by tailerons only, and a small Sukhoi 27 with a Simjet 700. All of them fly/flew with Futaba S9451 servos (one F-16 was instantly rekitted, but not because of the servos!!), and I never had a glitch or a problem with control authority on any of my jets. I always like to use the same brand servos as receiver and transmitter, as they are made to the same specifications. Make sure that you get servos that can handle 6 volts.

Good luck!

Tor

RCD

Don't forget Hitec digital servos. I have used them exclusively in my jets using Futaba equipment and have had zero problems.

They have an excellent range of servos and you can use 6 volts if you need extra output ( unlike JR) they are, of course, much cheaper than JR for an equivalent output.

John

I use 6 volts on all my aircraft, with JR digitals. Torque values are also provided by JR at 6V...What makes you think you cant use 6V? Futaba digitals (at least most of them) are only reated for 4.8V which is one of the main reasons I dont use them....

The Futaba S9451 is actually only rated at 6 volts on the package... and it's .10 sec and 8.7 kg/cm so it's a strong and fast one.

Tor

Todd

Apologies, you are , of course, correct. I have several JR non-digitals which quite clearly are marked "Do not use in excess of 4.8 volts" I did not realise this did not apply to digitals.

John

"I use 6 volts on all my aircraft, with JR digitals. Torque values are also provided by JR at 6V...What makes you think you cant use 6V? Futaba digitals (at least most of them) are only reated for 4.8V which is one of the main reasons I dont use them.... "

Took the words out of my mouth Todd. Although if you are using a voltage regulator, I dont think it matters if you use a 6V pack and a 4.8v servo. Any thoughts on this situation?

Mike

All the JR digital servos (mainly 8321 and 8511) that I have bought from the UK come with the following note (directly copied):

Please note that JR servos should be used with 4 cell (4.8 volt) NiCad batteries only. 5 cell NiCads MUST NOT be used.


The note is stuck to the outside of the box that the servo comes in. I am pretty sure that it is put there by Macgregor, the UK JR distributor, as the wording is identical to a page on their website. Why would they do this if 6V is OK?

Because 5 cell NiCads when fully charged reach voltages beyond 6V.... If your using a 5 cell pack, regulated to 6V is fine. Above 6V, JR digi's tend to get twitchy.... It is common in the states to regulate 5 cell NiCad and LiIon packs @ 5.1, 5.2, 5.6 and 6V.

Todd

That is the answer! I don't use regulators ergo JR digitals should not be used with unregulated 5 cell packs.No such problem with Hitecs.

john

Hi John,
There have been quite a few problems with the hitec digitals distributed in South East Asia, I have seen a 25 percent failure rate across more than two dozen 5945's when they were not used with a voltage regulator to hold the line voltage to 6 volts or below. I have not heard similar complaints from any where else. The biggest problem took place on the Hitec's sold in Singapore. I have not had or seen similar problems on 8411's that were not regulated. I have moved away from Hitec because of this, but again it may be a regional supply issue, which is still not a good sign.
Mike

Mike,
Care to elaborate on the types of failures your seeing?....

I used S3152 Futabas running 6 volts unregulated in a quick Baby Boomerang. No problems and nice crisp response with good neutrals.

Less buzzing than JRs I think.

lov2flyrc,
The failures have all been burn outs on the servo. High heat even with no load. It is indicative of over voltage. As you know a freshly charged 6 volt pack is more in the neighborhood of 7 volts. With a regulator holding to 6 volts or less, I have not seen this problem.
Mike