Jammin X-1 CRT motor selection
 

I am in the process of converting a X-1 CRT Pro to brushless. I eventually want this thing to be sick fast and would like to run 6s once the Monster Max comes out. I am planning on getting one of the less expensive motors and running if from my existing Mamba Max on 4s, then upgrading whenever the Monster combo comes out.

What motor is best for me and where can I get one? I have done the motor selection tool and top speed calculator and it looks like the 6XL or 7XL will work the best. Mike recommended a 8XL also. I am stumped on which motor to get that will give me about 50 mph and 20-30 min of runtime. I am looking at getting a set of maxamps 4s 4000 packs and running 2P. Is this a realistic expectation to get these speeds and runtimes?

Anyone have any suggestions on which (or another) would work best? I will not be racing, but just going fast and taking on big hills and jumps.

for 50mph i would go up in the number of cells.

50mph on 4S is pushing it currentwise.

Here, please read this;

http://www.rc-monster.com/forum/showthread.php?t=5115

You do NOT want the hot motors like 6xl or 7xl... especially on 6s lipo!!

I think a 9XL is the motor you should run. 50mph would be easy on 6s which is your target. 50mph on 4s would need a very tall gear but could do it if you really want to... 16/46 gearing would be around 45mph or so.

For 6s I would actually go lower... 10-11XL

here's the rpms at 21v for reference:
8XL 41400
9XL 36800
10XL 33100
11XL 30100

30K is plenty.... my truck/buggy run under 24/27k and they do 40+ easy

I wanted to do 6s once the monster max comes out (if it supports it). The motor that I'm looking for now will just run 4s and hold me over until the MMM comes out, that is why I want an inexpensive one instead of a lehner or neu. So how about the 7XL on 4s?

I am not sure if it will have enough grunt to push your truck realy well but try an xl5 if you wanna run 4s. I would probably go 5s with the 7xl I think. I am a noob and am having my little theories tested by the other members as well but that may help.

Cembom;

Please be easy with your advices. The 7XL on 5S in a short ratio truggy?

did you read the sticky in the brushless section?

The 7XL can do on 4S, though on 5 or 6S it will get burning hot in the short ratio vehicle.

It's kind of hard to get a motor that suits 4 and 6S. (that's in increase of 50 percent, so it's kind of hard to anticipate on that with gearing and the choice of the motor)



The 7XL on 5S in a truggy is asking for trouble.

Yes, I read the sticky. I am familiar with lipos, KV, stuff like that from elecric planes and helis. I am not looking for a motor to run 4s AND 6s, I was just saying in the future, I'd like to do 6s ON THE MONSTER MAX ESC AND MOTOR.

I just want an inexpensive motor that will give me close to the speed and runtimes I want on 4s with the Mamba max controller. Is it the 6XL, 7XL or 8XL?

appearantly I didn't read the 'combo' word in your opening post. No need to shout..

the runtimes would depent, and like i said; 50 mph on 4S is pushing it. (without the capslock) the controller, the motor and the batteries. the runtime you have in mind on 4S combined with that speed is rather hard. (8000mAh isn't enough)

Sorry, I wasn't yelling, just wanted to make my intentions clear. So will the 7XL be a good choice? (on 4s) I dont have to hit 50, just want a truck that is pretty fast. I have a stampede with a mamba max 5700 on 3s now and I love the power and speed it has. I'm assuming the truggy will not come close to that kind of power/ weight ratio though. If the 7XL will keep cool, give decent runtimes and speed it will be enough to hold me until I get the monster max.

I would go for the 8 or 9XL, since you are using a rather short ratio.

So, are you running the less expensive motor now because of the limited ESC's available, or for dollars? If it's dollars, then I have no options for you. If it's due to ESC, why not build with a great motor that you can deal with now and later? I'm going to run a Lehner 1940/10 hi-amp with the MM and a 4s in my X1 CRT and eventually go to a 6s. Just a thought.

And just a word to the newer guys (I guess this would include me) . . . this forum is not like the typical forums out there. There's no flaming, a lot of help, and a ton of knowledge. IMO - best forum on the web. So please just wait a minute before you respond in a way that might seem abrassive. The guys here are truely trying to help.

Good luck whichever way you go, the CRT is sick.

I could get a more expensive motor now, I just do not want to regret it when the monster max comes out. I am limited to 4s with my current esc, and I do not want to buy a new esc until the MMM comes out.

I was under the impression that the motors are closely linked with the input voltage, therefore the motor I'm running now may not be the best option when I switch to 6s, that is why I wanted to go cheap now and go all out when I can move up to 6s.

I do appreciate everyone's help and this seems to be a great forum. I did not mean to come off as abrasive if that comment was directed towards me.

Right on. I'm totally with you, and I'm building based on the same assumptions. I will go to the MMM and a 6s when they come out, but don't want to have a temporary motor. That's why I got the 1940/10 hi amp. It's a lower KV (1500) and will deal very well with the higher voltage later. You might try BrianG's motor calculator too. Very helpful. Here's a link for it:

http://www.scriptasylum.com/rc_speed/index.html

Welcome to the forum!

You can run a milder motor and gear up for now.. then swtich to 6s and gear back down. This isn't a perfect solution but it will work
.
You don't want to take the advice about going to a slower motor, so I would tell you to get the 7XL that you want right now and just plan on picking up another motor when the MMM comes out, or maybe they will have combo that fits what you want... we have no idea right now what the motors will be like. And they will have motors in the package at first, so they say.

Just buy the 7XL...........

I think I will go with the 7XL for now and upgrade later to the Monster Max.

What is an acceptable range of gearing? If I've read correctly, I only have the 46t kyosho in nylon for the spur?

Are the 7XL's hard to find? It looks like Mike is out of stock.

I wish the Monster Max had a date.. I cant hold out anymore with this CRT chassis taunting me! I can't wait to get this thing up and running!

Personally, I would just get a proper Lehner motor with the Mamba Max ESC and run it on 4S in Delta configuration.

In the future, you can get the Monster Max and then re-wire the motor to wye configuration, which will reduce its KV by 1.73, allowing you to run the 6S no problem.

This will allow you to buy just one motor, saving you money. I know you seem set on using the Monster Max system as a whole when it comes out, but I can pretty much guarantee you that a Lehner motor will be better.

Also, its probably better to get two 2S2P packs and wire them in series rather than a 2 4S1P packs and wiring then in parallel.

Someone is in a delty-wye mood.. :p

I would love to just buy one motor, I just thought that the KV would have to be alot different for 4s vs 6s. That is definately something to consider. I am not familiar with the delta configuration, I will do some research on it.

Also, what are the benefits of running in series vs. parallel? I do not have my packs yet, so I could do this, but running 2x 4s 4000 packs allows me to use them in an airplane as well as the truggy.

Nothing wrong with using the packs liek that. If you can get more use out of them with split packs go for it. I made up packs like that before (a pair of 2s packs) so I could run them in a 1/10 buggy at 2s or in my 1/8 at 4s.

The Feigaos are so cheap relative to the whole brushless project, I would not see the problem in planning to do two motors. Especially if a guy even thought for a second about getting a Lehner.... that $$ would buy like 4 XL motors...

If you want one motor... get 9XL. It's a good fit for your 50mph on 6s... and you can make do on 4s while waiting on the MMM. Gear it 18/46 and it will be very fast.

Seriously, I think you will find out that 50mph is overkill.. not that it's not cool... but low 40's is very fast and still jaw-dropping for most people.

Get some video if you have it running 50+..... I never gear mine that high so it would be neat to see it.

I dont mind spending the money on a Lehner if it is worth it. I hate buying cheap and then eventually ending up replacing it a few times. I'd rather get something good and it lasts, however if I do, I want it to work on 4s and 6s. If the 8xl or 9xl will work good on 4s, it's a no-brainer.

Glassdoctor, what is your opinion on running the lehner on 4s in delta configuration like mentioned above?

If you want something that will work at both 4s and 6s, I'd get one of the LMT motors. As BP-Revo pointed out, the coils can be reconfigured from D to Y by some solder pads on the back of the motor. This will let you run 4s when in D mode, and 6s on the Y mode and still run at the same total RPM.

However, at the cost of an LMT motor, you could get three XL motors with different kv ratings for whatever voltage range you want. The XL motors are good too, just not as efficient so they heat up a bit more. As long as you keep the bearings clean and make sure the end cap doesn't pop off (use the RCM heatsink/clamp), there's no reason why an XL shouldn't last a looong time.

Is this the 8XL that I need?
http://www.rc-monster.com/proddetail...540C_XL&cat=20

Or this one? (8XL out of stock)
http://www.rc-monster.com/proddetail...WAND_XL&cat=20

Yup, both of those are the about the same performance wise.

If it were me, I'd get the BK XL (despite the fact they're out of stock) with the seperate RCM heatsink. I know the Feigao one has a built-in heatsink, but there have been instances of the end bell popping off. The RCM heatsink with the regular 8XL is quite solid.

This motor would work to, looks like there in stock.
http://www.rc-monster.com/proddetail...o5408xl&cat=20

Get the RCM heatsink like BrianG said to keep it cooler and stop it from falling apart. You could use it on the other motor you get for 6s as well. I assume MMM motors will be the same diametre. If you get a Lenher 1940 later, the L size heatsink should fit (it will fit an XL motor to), but the XL size heatsink may be too long for the 1940..I'm not sure, something worth looking into before you decide what to get though.

Well, some of my excuse to myself for blowing 350+ on a 1950 is the reduced blood pressure of not having to deal with pressed endbells. LOL

After seeing MetalMan's come apart a couple times, I didn't want to deal with that PITA. I'd probably pull my hair out the third time it happened.

Serum - Call me Delta-Wye boy from now on LOL.

There is a solid point that a few XL's can be had for the price of one Lehner. Doing dual BL would also be a nice eye-catcher - and you can choose how fast you wanna go by using 1 or both systems (you'd just need a spare pinion to put on, since you will probably run higher gearing with 2 motors). Also be a good idea to move the other motor off the mesh so it wont spin when you are just using one.

It only happened twice, one time for each of my two motors. JB Weld does a very good job of fixing this, and so far my JB-Welded motors are holding up fine.

That's the reason why Mike made the heatsink for these motors.

So is there any benefit of the above linked motors? Should I just get the one that is in stock? I will definately pick up a heatsink while I'm at it.