racer rich

In the "touring scoop" section of the RC Car Action's latest Touring Car magazine, they have shown the new Futaba S9550 Digital Servo. They state that Futaba claims this is the ultimate touring-car servo for nitro and electric applications. They also wrote that it was the same servo used by Surikarn Chaidajsuriya to win the recent IFMAR ISTC World Championships in South Africa.

I think this servo will be great for my Reflex since the servo in the Reflex (and many other 3-Belt nitro touring cars) has a direct steering system that is mounted to the upper-deck and the very low-profile design of this servo will really lower the car's overall CG.


This servo is rated at:

Speed- 0.11/60 degrees at 6 volts

Torque: 80.5 oz.-in
(5.8kg/cm) at 6 volts)

But I have a few questions though. Will this servo be powerful enough for a 4WD nitro touring car? It seems like a great idea but I don't want to put an under-powered servo in my car. The Reflex like I previously stated has a direct steering system so when the car hits any bump in the road the force is directly transmitted to the servo. Will this servo be able to handle this abuse without failing or breaking?

Does anyone have any experience or know anyone who has had experience with this servo? How is its performance in an nitro touring car? Will it provide an ample amount of torque or is it kind of on the short side of power?

I looked on Futaba's website about this servo and their description of it has no mentioning of any particular use for RC cars. In fact, here is the exact description:

"Low profile design allows the servo to fit into wings and lay down down in car chassis for less obstruction."

This is what is kind of confusing me. Could this servo be used effectively in a nitro touring car like RC Car Action stated?

I use a JR-R1 PCM Radio with the R330S 75MHZ 3-Channel SPCM Reciever. Will this servo be compatible with my radio system? Also, Futaba uses a "different" shape wire plug. It has a little "ear" on it that the JR plugs don't have. In my experience Futaba plugs don't fit into JR receivers. So I think I am going to have to change the plug or cut the "ear" off. Does Futaba make a version of this servo to fit JR recievers? I use a Futaba switch with my R330S receiver, and in order to make it fit in the receiver slot I had to cut the little "ear" off the Futaba plug to make the plug perfectly sqaure (the reciever slot on JR recievers is perfectly square). I am thinking I might have to do that with this servo if I purchase it. Only problem is, if I screw up a switch costs $6 and a new servo costs $90! Would you advise to do that to make the Futaba plug fit to my R300S receiver?

Thanks in advance!

icon

Lets put it this way. I've used S9404 servos (which has a similar torque compared to the S9550) for all my 1/10 cars and I've never had a problem. 80 oz/in is fine for a tourer. Most servos are overkill for 1/10 application. If you dont feel safe using the S9550, then I suggest the a S9402 or if you want a digital use the S9450. They are not low profile, but they have around 100 oz/in.

racer rich

Thank you for your reply icon.

One last question. Do you guys think that the S9550 servo will provide enough torque and power for strong braking? I would love to get one for the brake linkages as well, although probably not needed, the extra weight loss is something I can benefit from.

Thanks again!

icon

yes, the 9550 definitely has enough torque for the brakes. but is it really necessary? i'm using a S9101 for throttle/brake. its rated at around 44 oz/in and its doing fine. digital servos consume a lot of juice. if your using a pair of them, your run time with the RX batt will be reduced. that is why i'm reluctant to switch over to all digital (besides the cost).

wtleadfoot

Ko propo 2143,s are .06 at 111 oz of torque.
By far better than futaba at or better in price.

InitialD

Well, the information about Futaba being inferior is incorrect. The 2143 may be better than the 9550 but Futaba has the 9450 which is also rated at 111 oz of torque but at 0.10 seconds at 4.8V. The 2143 figures are rated at 6V.

Extrapolate the 9450 specs to 6V, you'll get 138.75 oz of torque at 0.08 seconds.

Weight wise, the 9450 is 0.5 grams heavier than the 2143 FWIW.

Boomer

Shoot, I use Airtronics for all mine except for a teeensy little Multiplex in my Pro10. . .

If you wanna use Futaba, go ahead, don't listen to the brand snobs!

You don't really need all sorts of torque for braking, it takes less than steering does since you are pulling on a lever that turns a cam that moves the brake shoes. It doesn't take much force, not really.

Still, get a decent one! And speed is far underrated for throttle/brake servo. I'm actually running an Airtronics 257 as mine - made a huge difference over my 737 (decent speed, decent torque) - better throttle and brake reactions!

racer rich

Well I want to use a S9550 for the throttle/brake because it will allow me to mount a transponder directly under it. This will keep the weight closest to the centerline of the chassis as possible and maintaining the lowest CG. I can make a mount out of lexan for the transponder quite easily.

On the V1RR it does come with a transponder mount, but the transponder will actually mount off to the side of the throttle/brake servo, not directly under it. It will also be mounted a little higher up as well.

I am thinking about purchasing it from a online shop in Hong Kong. It is rcmodel.com.hk . They sell the S9550 servos for $78.00 while Tower Hobbies sells them for $119.99. Thats quite the savings!

I have one question. Does the exact same item that sells overseas (in this case Hong Kong) differ in any way from the exact same product that will be sold here in the U.S.? I just want to make sure beacuse it sounds too good to be true for the exact same item to be $40 less elsewhere. Its either in some way different or the U.S. distributors want to make quite the nice profit!

Thanks in advance!

Sydewynder

They are the same. Only difference maybe on some models is the name. ie. Airtronics use number in the US, 9xxxx while in Asia it might be WR, ZR etc.

Digital Futaba 9450 can be found for $70USD instead of the $100 ++ here.

KO 2143 and 2144 in the US are about $115. In HK they're around $75USD.

Yes the U.S. distributors make a nice profit.

BeaV1s

I've been using a 9550 on my throttle/brake for my v1r and it performs great. Just make sure you adjust the linkage properly so that you don't place too much stress on the servo. Otherwise you might break it or consume too much power. It made a big difference in braking performance and throttle response over a standard, enrtry-level servo and it's much smaller.