Kraton EXB - recommend me some electronics

[Jimbobjr]

Anyone know if the servo saver is the same. All mine are the old style except the talion which is non adjustable. Steering only improves so much with a strong servo n the fixed ones.

 

[wishiwereaskibum]

Good stuff here. What’s everyone think about the solar brand servos? Reliable? Actually meet stated specs? The 772 is 3) kg-cm at 7.2 v, and I’m wondering if this is close to enough torque? https://www.hobbypartz.com/33p-solarservo-d772.html

above comment, that jx CLS with 46 kg-cm of Torque... youzer... .. but, reading the specs, it’s really only 120deg working angle.... is that sufficient for steering or wouldn’t you want the extra 30 degrees per side that would translate into ... I’m not sure, at least some additional steering ( albeit only needed at very low speeds but I find a tight turning radius very helpful myself)

 

[wishiwereaskibum]

Hey, I’m replying to Sonsi and chrisexv6 post /response about battery capacity and voltage. I was struck by the reply of more voltage is more power and felt the need to enlighten and clarify.

The voltage is not directy tied to power. Motors have Torque and speed constants.. In this hobby we keep it simple and talk about the motor speed constant, generally referred to as back EMF of a motor and in the servo world called Kb or Ke, but referred to as Kv for hobbyists.


Battery cell count provides more voltage at call it 4 volts nominal per cell.

Cells are often hooked up in series so the pack voltages increase with the number of serial connected cells. A 3S pack has 3x 4 V or nominally 12 V under no load.

Motor speed is the applied voltage x the Kb ( referred to as Kv in the hobby world but this is not quite an accurate pure servo term... but I digress) so a 12 v battery pack, given the same motor will spin the motor 1/3 faster than a 2S pack that has 8V nominal. Makes sense?

Now you can’t have your lunch and eat it too. Motors also have the thing called Kt or torque constant. And Kt is inversely proportional to Kb ( or Kv ) so the opposite Effect happens. a motor that spins twice as fast per applied volt also produces half the torque per Amp drawn or flowing through the windings. requires twice the current to produce the same amount of torque.

make sense?

So basically, battery voltage is not power. Voltage is proportional to speed and current is proportional to Torque. Power is speed x torque / constant ( the constant being 5252 if I recall correctly and we’re talking rpm for speed and in-lb of torque, but it’s been a while...)

party on, geek out a bit, bash our cars, fly our helis, charge our batteries, and by all means have fun!!!

 

[Meanadidas]

I purchased the PowerHobby 729MBL from Amazon for $89.
@ 7.4V it has 500oz torque and a transit time of .100sec. Its a HV servo and the reviews and pricing are fantastic. Its a great looking servo too.

 

[Lbrownjr]

I know you say 6s is fine, but what the future holds might be different. A small price upgrade with a Hobbywing Max 5 runs great on 8s, even better on 6s. No problem starting with a 6s setup with the HW 1650KV. Later on 8s the 1100KV is a monster. I know that is what I am doing now, and getting ready for future 8s.

Is the Max 5 a direct fit on the Kraton 4V?

 

[Jake4k]

Hi all,

First post in the forum. I have been reading and learning the last couple of months, and I just wanted to start by thanking all of you! ?

My question is.. I bought a Kraton 4s about 6 weeks ago, and I have pre-ordered the EXB. I would like to know if I can take the ESC (BLX120) and the motor from the 4s and use it on the EXB until I feel I can afford a better ESC/Motor combo for the EXB (and then swap the 4s system back in the 4s...). Do you guys see any problems in that? I am running the Kraton 4s on a 15t pinion (from the stock 13t), but maybe I should go for the 13t in the EXB because if the extra weight/larger wheels?

I already got a better servo for the purpose (and a Dumbo..) I am not totally new to the hobby, but the Kraton 4s is my first RC with 4s power (which still is enough for me)..

 

[Lbrownjr]

Hi all,

First post in the forum. I have been reading and learning the last couple of months, and I just wanted to start by thanking all of you! ?

My question is.. I bought a Kraton 4s about 6 weeks ago, and I have pre-ordered the EXB. I would like to know if I can take the ESC (BLX120) and the motor from the 4s and use it on the EXB until I feel I can afford a better ESC/Motor combo for the EXB (and then swap the 4s system back in the 4s...). Do you guys see any problems in that? I am running the Kraton 4s on a 15t pinion (from the stock 13t), but maybe I should go for the 13t in the EXB because if the extra weight/larger wheels?

I already got a better servo for the purpose (and a Dumbo..) I am not totally new to the hobby, but the Kraton 4s is my first RC with 4s power (which still is enough for me)..

If it was me, I would sell the 4s. I will let the more experienced chime, but I would not run BLX 120 in a 6S vehicle. Don't know if it will overheat all the time because of the vehicle weight difference.

If it was me, I would sell the 4s. I will let the more experienced chime in, but I would not run BLX 120 in a 6S vehicle. Don't know if it will overheat all the time because of the vehicle weight difference.

 

[jondilly1974]

BLX185 is the bare minimum and even that will tend to heat up some in the heavier EXB.

 

[Lbrownjr]

BLX185 is the bare minimum and even that will tend to heat up some in the heavier EXB.

@jondilly1974 I was trying to find a post where I believe you were talking about the MMX8S or Maxx5; do both of those direct fit V4 Kraton 6s? Was going with Maxx6, but considering a change since cost difference is not significant. Thx

 

[jondilly1974]

@jondilly1974 I was trying to find a post where I believe you were talking about the MMX8S or Maxx5; do both of those direct fit V4 Kraton 6s? Was going with Maxx6, but considering a change since cost difference is not significant. Thx

Never had a MAX5 so idk there. The MMX8S you will need double sided tape to stick it to the stock ESC plate. I think you will need to trim off some minor plastic for it to fit flat.

 

[Jake4k]

Ohh okay, glad I asked then, thank you guys! I guess I will be looking into finding another solution If not found in time before the EXB arrives, I will have no problem just looking at it for a few days Such a beauty! .. According my local hobby store, they got a hold of a few EXB which should arrive next week (Denmark) - fingers crossed ?

 

[Lbrownjr]

Never had a MAX5 so idk there. The MMX8S you will need double sided tape to stick it to the stock ESC plate. I think you will need to trim off some minor plastic for it to fit flat.

I found the post, I believe you run the MMX8s(under the "Dear Castle" thread). I could not recall if it was the MMX or the Maxx5. I see that you recommend the MMX a lot to keep temps down. I believe I will go with the MMX and pair with a 4092 1730kv whenever I find one available.

 

[BashingBrian]

https://www.mgm-controllers.com/car...ost-powerful-esc-motor-combo-for-rc-cars.html

I've pre-ordered one of these for my EXB...?
???????

 

[jondilly1974]

https://www.mgm-controllers.com/car...ost-powerful-esc-motor-combo-for-rc-cars.htmlView attachment 90311

I've pre-ordered one of these for my EXB...?
???????

I believe @BitcoinGTR has that setup in hand

 

[MDRex]

When people say the temps will be much lower on the MMX8s with 1650kv combo, is this true when running 6s? I have the Max6 1650kv combo but debating getting the MMX8s combo to keep temps down more.

 

[MDRex]

Nevermind.

 

[Mud Creek RC]

Anyone have insight in to this combo: Tekin 1/8 Rx8gen3 BL ESC 4030 T8gen3 BL Motor 2050kv

 

[DustyPickleJarz]

In my

Anyone have insight in to this combo: Tekin 1/8 Rx8gen3 BL ESC 4030 T8gen3 BL Motor 2050kv

In my opinion, Tekin is amazing for racing or for light weight vehicles. Once they start pushing weight they tend to run a little hot. I would rather get MMX8s for than run the risk of overheating a perfectly good RX8.

Fyi... Amain Hobbies have some MMX8s w/1717 in stock

 

[walloftvs]

First post on the forum here and totally new to your rigs (I've got an EXB on backorder), so please excuse my ignorance.

How are you guys getting the Castle 1717 to fit? Different motor mount?

The specs on the Arrma site say that the max motor diameter is 43mm (140mm length) and the 1717 is 47.6mm in diameter.

 

[bicketybam]

First post on the forum here and totally new to your rigs (I've got an EXB on backorder), so please excuse my ignorance.

How are you guys getting the Castle 1717 to fit? Different motor mount?

The specs on the Arrma site say that the max motor diameter is 43mm (140mm length) and the 1717 is 47.6mm in diameter.

It's a direct fit.