Question about high torque & high speed servos

[CessnaDriver]

Hello fellow R/Cers.

My Mugen MBX5 ProSpec build is going quite well and is starting to take shape and is actually starting to look like a buggy.

I will post pics soon.

I am at a point in the build now to where I need to install the servos. I will be using the JR 8800T (188oz/in & .15 sec/60 degrees)& the JR 8800S (105oz/in & .08/60 dergrees).

My question is which servo should I use for what?

Logic says to use the high torque servo for steering and the high speed servo for the throttle/brake. However I was also thinking if I use the high torque servo for the throttle/brake, then I would have plenty of brake power without the worry for fading.

Also I was thinking that the high speed servo with its 115oz/in is still quite enough for the steering.

What do you all think about this? Comments? Suggestions?


P.S. As far as the build is concerned, so far it has been solid and a very high quality kit, with the exception of two things that I think need improving.

The first being the piece that the big,chrome, metal set screws go into on the front upper control arms. That plactic piece should be metal also and then require loc-tight. It was a bitch to get those big set screws in there straight all the while trying to not strip the plactic threads.

The other being the plactic side guards that attach to the chassis. The holes where you put the lock nuts in are not snug and before you can tighten the screws, the lock nuts strip and goes around with the screw. I had to take a pair of needle-nose pliers and press the plactic down real hard to get enough of a grip on the nuts to keep them from turning with the screw.

Other than that I am real satified with this kit.

 

[HeartBreak]

Trust me, brake fade is NOT an issue with this car; It will stop on a dime and give you change. I have a Hitec 525MG on the throttle, and it's more than enough to cause the tires to skid at a braking from 1/4 throttle (on pavement).

Personally, I'd put the high torque on the steering. You're going to need that grunt to heft the tires over while they're spinning.

 

[J_Bone]

Steering
JR 8800T (188oz/in & .15 sec/60 degrees)

Throttle
the JR 8800S (105oz/in & .08/60 dergrees).

I prefer more torque on steering and speed for throttle.

 

[robriguez]

well, I may be wrong here (this is just my opinion):

You dont need alot of torque or speed on a throttle/brake servo. Well enough torque to provide good braking. HS545 is fine. Especially if it has dual or quad brakes.

For steering, You want the quickest digital servo your wallet can afford. The reason, most buggy tracks will have you going through s-turns or chikanes(sp?) and you will need to go from full left to full right and back again as quickly as possible. Buggy tires are light, the steering geometry makes it so steering is easy, so having UBER torque is not necessary. You just want something that is strong enough to still give you very fast turning under braking when the full weight is on the front end. Anything over 100oz should be fine.

 

[Plaidfish]

well, I may be wrong here (this is just my opinion):

You dont need alot of torque or speed on a throttle/brake servo. Well enough torque to provide good braking. HS545 is fine. Especially if it has dual or quad brakes.

For steering, You want the quickest digital servo your wallet can afford. The reason, most buggy tracks will have you going through s-turns or chikanes(sp?) and you will need to go from full left to full right and back again as quickly as possible. Buggy tires are light, the steering geometry makes it so steering is easy, so having UBER torque is not necessary. You just want something that is strong enough to still give you very fast turning under braking when the full weight is on the front end. Anything over 100oz should be fine.

I have to disagree w/ this one.....the higher torque IS needed on the steering not because the buggy is heavy like an MT but the forces on them when taking corners at 30+ will eat the lower torque servos and you start to get wheel wander in th ehard corners......the speed is needed more on the T/B set because in the air you'll need much fawster response time to correct your, UMM irradic flight patterns?!?!?!....

 

[Buggyracer28]

Yeah, the mbx-5 has AMAZING brakes. I have a JR570 in my throttle and its perfect. I just gotta rebuild my brakes because I'm having trouble adjusting the front.

 

[CessnaDriver]

Ok, I decided to go with logic. I am using the Torque servo for steering and the speed servo for throttle/brake.

I think that even the speed servo with its 105oz/in of torque will be enough to clamp down on the brakes with authority.

Thanks for all your comments. I just finished installing both servos and just got done doing the fine tuning on the steering servo.

 

[HeartBreak]

You'll be happy with that combo. I've been thinkin of upgrading my steering servo to something a bit better in my Mugen. The steering is fine for just putzin around, but I can tell it's gonna have to be better for racing.

 

[CessnaDriver]

HeartBreak: I have run into a snag in my build and since you have a Mugen also, you might be able to help.

I am working on putting the clutch on the engine. The engine comes with a cone shaped washer that the flywheel sits against.

BTW the rngine is the Novarossi P5X

In the manual it shows a washer going inbetween the that cone shaped thing. However I didn't see that until I had already put the flywheel on and tightned it and tryed to put the clutch shoes on and the spring didn't line up where they were supposed to go on the locknut.

Now I can't get the flywheel off. Do I need a special tool to get that thing off?

Also on the bell housing there are two ball bearings that go on both sides, but they do not fit over the shaft on the engine. Do I need to take off the screw on the engine shaft to put the bearings and bell house on? I was going to try that, put then I was looking at the blown-up version of the engine sheet and that screw goes directly into the crank shaft and I'm not sure if by removing that screw from the crank shaft if I would screw anything up.

Thanks

 

[niggle]

I have to disagree w/ this one.....the higher torque IS needed on the steering not because the buggy is heavy like an MT but the forces on them when taking corners at 30+ will eat the lower torque servos and you start to get wheel wander in th ehard corners......the speed is needed more on the T/B set because in the air you'll need much fawster response time to correct your, UMM irradic flight patterns?!?!?!....

Gotta agree with Plaid' on this one. At full chat, the front wheels are like gyroscopes and you need adequate torque in your servo to make the wheels point where you want.

 

[RcTire]

who uses brakes??? lol

Put the high torque one you have on steering and other on t/b....

 

[HeartBreak]

HeartBreak: I have run into a snag in my build and since you have a Mugen also, you might be able to help.

I am working on putting the clutch on the engine. The engine comes with a cone shaped washer that the flywheel sits against.

BTW the rngine is the Novarossi P5X

In the manual it shows a washer going inbetween the that cone shaped thing. However I didn't see that until I had already put the flywheel on and tightned it and tryed to put the clutch shoes on and the spring didn't line up where they were supposed to go on the locknut.

Now I can't get the flywheel off. Do I need a special tool to get that thing off?

Also on the bell housing there are two ball bearings that go on both sides, but they do not fit over the shaft on the engine. Do I need to take off the screw on the engine shaft to put the bearings and bell house on? I was going to try that, put then I was looking at the blown-up version of the engine sheet and that screw goes directly into the crank shaft and I'm not sure if by removing that screw from the crank shaft if I would screw anything up.

Thanks

Okay, first question The flywheel is fairly easy to remove with common tools. To remove it, you'll need a decent sized pair of channel locks (I HATE piston lockers!), and the wrench that you used to install the nut.

What you'll do is grab the flywheel in the pliers. Next, you'll remove the nut. Once you get the nut off, you'll notice that the flywheel is still on the 'collet' (cone shaped washer, also called a 'corn'). This is easy to overcome. Simply put the crankshaft onto a wooden surface that you don't care about (that old antique oak dining table will suffice), and give the back side of the flywheel a couple of taps. Just two or three gentle ones should be enough to knock it loose.

Now, as for the screw on the end of the crankshaft, you will need to remove that screw. Don't worry; the tip of the crankshaft is all one peice, and removing that screw won't cause any harm.

Now, as for the shoe springs (I believe that was your question), you will have to force them over the nut into the groove on the nut. The tool of choice here is a screwdriver with a small notch in the blade.

Hope that helps!