RE: Xray M18T and M18MT RTRs!

RE: Xray M18T and M18MT RTRs!
View related threads: (in this forum | in all forums)

Logged in as Guest

Users viewing this topic: none

Search This Thread

Printable Version

All Forums >> RC Cars, Buggies, Trucks, Tanks and more >> 1/16th, 1/18th, Mini & Micro RC Cars >> RE: Xray M18T and M18MT RTRs! Page: << < prev 11 12 13 14 15 16 17 [18] 19 20 next > >>

Login

Message

<< Older Topic Newer Topic >>

RE: Xray M18T and M18MT RTRs! - 12/11/2008 8:19 PM

DarkHorse

Posts: 339
Score: 100
Joined: 4/22/2005
Last Login: 3/21/2010
From: Gloucester, UNITED KINGDOM
Status: offline

> ...looking to take the next step in power.
> I plan on racing on a tiny carpet track where I hardly run full speed.

Briefly: Lithium packs weigh less for the same energy as NiMh pack.
Using lithium packs (I always use 3s 11.1v packs to pull less Amps, Power=Amps*Volts) you need a Low Voltage Cutoff (LVC) feature on the ESC to avoid over discharging lithium cells. The safe threshold is considered to be 3v per cell under load, which is 9v loaded for a 3s pack, where you want the ESC to start soft clipping the power output to preserve the cells from damage. Normally the LVC is a programmable feature (via Tx sequences) on brushless ESCs like the Mamba25 or better.

Brushless motors are more efficient than brushed motors, converting less electrical energy in to wasted heat. Also don't have to worry about brush gear and comm wear. As a result you can get up to 20% more runtime using the same energy as running the brushed motor or say +20% more power for the same runtime (generalizing greatly for simplicity).

Coupled together, the greater energy density of the lithium packs (normally lighter weight) with the greater brushless motor efficiency is a better setup but at a cost, particularly if switching over from brushed and NiMH packs. If your happy with a brushed system, runtime and performance then upgrading may not be worth the effort and cost.

< Message edited by DarkHorse -- 12/11/2008 8:20 PM >

_____________________________

DarkHorse RC: Hornet X-3D, Ecureuil, Airworlf, X-ray M18T, Power & Setup Calculators ;) http://dhrc.rchomepage.com/

Hide Signatures

(in reply to bmoir)

Post #: 426

RE: Xray M18T and M18MT RTRs! - 12/11/2008 10:01 PM

pete2222

Posts: 134
Score: 100
Joined: 9/12/2004
Last Login: 11/12/2009
From: KentEngland, UNITED KINGDOM
Status: offline

Hey Darkhorse,

My M18T is running well with my new 6800kv motor. I got 25min runtime with a standard intellect battery and the top speed is as much as I need for now. I was wondering though,
how much faster is it with the 3S lipo in? Is there a big noticeable difference and do you think it's worth paying up for a new battery plus charger.

Hide Signatures

(in reply to bmoir)

Post #: 427

RE: Xray M18T and M18MT RTRs! - 12/11/2008 10:48 PM

DarkHorse

Posts: 339
Score: 100
Joined: 4/22/2005
Last Login: 3/21/2010
From: Gloucester, UNITED KINGDOM
Status: offline

...I've never used the 'intellect battery', 6s1200mAh 7.2v?

If your already 2s 7.4v (or 6s1200mAh 7.2v) and quite a high Kv motor it might not be worth the hassle going to 3s (11.1v lipo) in the Xrays (though I would try it).
Just dropping in a 3x1200mAh 11.1v pack on the same gearing, you would notice a significant increase in top speed and better punch out acceleration. A 6800Kv will be a pretty hot (temp) on 3s even with a 8T pinion, my Mamba 5400Kv gets pretty hot on 10T, ~30mph, up to mid range wheelies on demand on good surfaces (without a wing).
One benefit is the same power levels can be hit with less Amps in the wires which means less heat wasted in wires, cells and ESC etc. Or you can pull the same Amps at higher voltage for more max power. Say 15A x 11v = 165w compared 15A x 7v = 105w, getting the power to the road is another story

. I think you will prefer the performance characteristics of 3s, comparing 9-10v to 6-7v at the end of a pack feels pretty soft to me.

Edit: Thunder Power (or Flight Power) 3x1320mAh packs 85g to 100g depending on C rating and normally lasts 30 to 40mins tooling around (very drive demand dependant).

< Message edited by DarkHorse -- 12/11/2008 11:02 PM >

_____________________________

DarkHorse RC: Hornet X-3D, Ecureuil, Airworlf, X-ray M18T, Power & Setup Calculators ;) http://dhrc.rchomepage.com/

Hide Signatures

(in reply to pete2222)

Post #: 428

RE: Xray M18T and M18MT RTRs! - 12/12/2008 12:12 AM

patatchim

Posts: 124
Score: 100
Joined: 6/5/2006
Last Login: 3/19/2010
From: pt, PORTUGAL
Status: offline

I´m using a 3s1p 1.7A in my m18mt, with a 5400kv motor, 10t pinion. It´s insane. You have to be very gentle on throttle input

. Runtime = 25 minutes, pushing it hard.

_____________________________

hk-t500;Mini titan;mosquito | 1/16 slash brushed ; wheely king | in the shelf: Tl-01b;Rc18b ;Xray m18mt;

Hide Signatures

(in reply to DarkHorse)

Post #: 429

RE: Xray M18T and M18MT RTRs! - 12/12/2008 7:01 PM

DarkHorse

Posts: 339
Score: 100
Joined: 4/22/2005
Last Login: 3/21/2010
From: Gloucester, UNITED KINGDOM
Status: offline

5400Kv 54T/10t pinion with larger 70mm M18MT tires is probably a bit too fast at top speed

, gets a bit warm if that's a Mamba short motor.
With a similar 3s setup on 8T pinion the motor gets pretty hot some times (depending on air temps) but I'm mostly stop start bashing about pulling Amps across the rev range which may cause more heat than mid range cruising (not sure about that though).
Do you have to run in cold air, heat sinks or run a fan cooler or just stop for intervals?

_____________________________

DarkHorse RC: Hornet X-3D, Ecureuil, Airworlf, X-ray M18T, Power & Setup Calculators ;) http://dhrc.rchomepage.com/

Hide Signatures

(in reply to patatchim)

Post #: 430

RE: Xray M18T and M18MT RTRs! - 12/12/2008 11:30 PM

patatchim

Posts: 124
Score: 100
Joined: 6/5/2006
Last Login: 3/19/2010
From: pt, PORTUGAL
Status: offline

DarkHorse , I have a small fan just moving a little bit of air. It doesn´t get to warm although i´ve already melted a pinion.

10t is the maximum that i can use on this car. To much current draw after that.
8T would be the ideal pinion, But i don´t have one now so...

With a 12t pinion, here a small run that i´ve made
If you see the current that the motor is pulling, it´s a little bit out of range... I cannot explain how i don´t have anything damaged.

Attachments

Click to see fullsize image.

Click for fullsize

_____________________________

hk-t500;Mini titan;mosquito | 1/16 slash brushed ; wheely king | in the shelf: Tl-01b;Rc18b ;Xray m18mt;

Hide Signatures

(in reply to DarkHorse)

Post #: 431

RE: Xray M18T and M18MT RTRs! - 12/13/2008 10:47 AM

DarkHorse

Posts: 339
Score: 100
Joined: 4/22/2005
Last Login: 3/21/2010
From: Gloucester, UNITED KINGDOM
Status: offline

I can't figure those numbers out either...

the peaks seem to climb gradually and then stop abruptly mostly drawing 4 Amps continuous.
What driving is the truck doing on the ground?
What 5400Kv motor is that?

Another problem I see is that the average Amp draw is ~18A (200w), if that where true then your 1700mAh 3s pack would drain dead in 5.6 mins?

A 25min runtime would average ~4A (45w), more like what I would expect with 10A to 20A spikes using a 120w rated Mamba5400 motor.

< Message edited by DarkHorse -- 12/13/2008 10:55 AM >

_____________________________

DarkHorse RC: Hornet X-3D, Ecureuil, Airworlf, X-ray M18T, Power & Setup Calculators ;) http://dhrc.rchomepage.com/

Hide Signatures

(in reply to patatchim)

Post #: 432

RE: Xray M18T and M18MT RTRs! - 12/13/2008 3:46 PM

patatchim

Posts: 124
Score: 100
Joined: 6/5/2006
Last Login: 3/19/2010
From: pt, PORTUGAL
Status: offline

Darkhorse, total runtime was actually 4m:52s
For making that run, i was going, soft throttle, half, full, brake.

Its a 12t pinion, the motor is a 5200kv not a 5400kv has i´ve said. http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=4214&Product_Name=KB20-30-18S_5200kv_Brushless_Motor_(FIN)

The battery is a xpower 1.7A 11.1v, 12-15c continous, 20c peak. (34 amps maximum, you can see on the graphic that the motor was drawing way above that..)
The speed controller, is a dynamite mini tazer esc. Continuous Maximum Current:25A

I was suspecting i had some kind of problem, since my runtimes were to low, 4 to 6 minutes.
I still don´t know how all the things are working properly since they were quite out of tolarance range.

My driving is bashing, just going half throttle, full, brake... do a little spin on instant full throttle, nothing special.

< Message edited by patatchim -- 12/13/2008 3:47 PM >

_____________________________

hk-t500;Mini titan;mosquito | 1/16 slash brushed ; wheely king | in the shelf: Tl-01b;Rc18b ;Xray m18mt;

Hide Signatures

(in reply to DarkHorse)

Post #: 433

RE: Xray M18T and M18MT RTRs! - 12/13/2008 4:39 PM

DarkHorse

Posts: 339
Score: 100
Joined: 4/22/2005
Last Login: 3/21/2010
From: Gloucester, UNITED KINGDOM
Status: offline

I think those B20s are clones or equivalent to the old hackers B20s but with heat sinks. rated max 12A*12v = at best 144w continuous power, 20A peaks would be about max.

> Its a 12t pinion,
Yes I missed that bit.

> was suspecting i had some kind of problem,
> since my runtimes were to low, 4 to 6 minutes.
Not sure but I would also have to suspect the motor, if they cook the magnets can weaken (increasing the Kv, lowering the torque) becoming less efficient generating more heat... weakens the magnets and so on, until the motor coils begin to short out. That could be the problem, an average of 200w of energy has got to go somewhere (if the log is accurate).
.

_____________________________

DarkHorse RC: Hornet X-3D, Ecureuil, Airworlf, X-ray M18T, Power & Setup Calculators ;) http://dhrc.rchomepage.com/

Hide Signatures

(in reply to patatchim)

Post #: 434

RE: Xray M18T and M18MT RTRs! - 1/23/2009 4:23 AM

fisheydude

Posts: 219
Score: 100
Joined: 12/19/2007
Last Login: 1/16/2010
From: bowling green, KY, USA
Status: offline

Hey guys. My brushed motor has finally gave out. I am finally ready to go brushless, I am a brushless virgin. I have reread through this thread and figure that something from castle creations is what I think I want. What are some suggestions for a good package that is reliable? I have a 2s 1550mah lipo to use with it. I was curious of the difference in the Mamba Micro Pro and the SideWinders. They look the same but the Micro Pro lets you program more stuff? I am looking for something for more low end. I guess the 5400Kv setup for hill climbing and off-roading. I want to keep temps down, that is one concern. Would the 9T pinion be cool? I guess I will also need that aluminum motor mount plate to make it work, is that all to make it bolt right up? I have more questions but I think I will wait for some responses. Thanks.

_____________________________

If it''s a monster truck, drive it like a monster truck!

Hide Signatures

(in reply to DarkHorse)

Post #: 435

RE: Xray M18T and M18MT RTRs! - 1/23/2009 8:07 AM

alex.guzun

Posts: 178
Score: 100
Joined: 4/18/2008
Last Login: 3/19/2010
From: Lab, SLOVAKIA
Status: offline

I'd buy 5400 too, motor mount, drive shafts, later diffs and metal spur
Let our guys say more

_____________________________

VEKAmodel
ABEC35.com - Ceramic and Engine BEARINGS

Hide Signatures

(in reply to fisheydude)

Post #: 436

RE: Xray M18T and M18MT RTRs! - 1/23/2009 2:52 PM

RC Huligan

Posts: 372
Score: 100
Joined: 12/15/2007
Last Login: 1/31/2009
From: Charlotte, NC, USA
Status: offline

quote:

ORIGINAL: fisheydude

Hey guys. My brushed motor has finally gave out. I am finally ready to go brushless, I am a brushless virgin. I have reread through this thread and figure that something from castle creations is what I think I want. What are some suggestions for a good package that is reliable? I have a 2s 1550mah lipo to use with it. I was curious of the difference in the Mamba Micro Pro and the SideWinders. They look the same but the Micro Pro lets you program more stuff? I am looking for something for more low end. I guess the 5400Kv setup for hill climbing and off-roading. I want to keep temps down, that is one concern. Would the 9T pinion be cool? I guess I will also need that aluminum motor mount plate to make it work, is that all to make it bolt right up? I have more questions but I think I will wait for some responses. Thanks.

I know you're looking for the 5400KV brushless motor, but I have the Mamba 25 ESC and 8000KV brushless motor (Competition X package) that I'm trying to sell used. We decided to slow down our M18s for driveway racing. Here are the pics for both.

Motor: http://twitpic.com/sv07

ESC: http://twitpic.com/suva

They worked great for us and are crazy fast. I'm selling the ESC and motor together for $75. This also includes the blue XRAY heatsink you see in the photo. Here's a video of my XRAY M18 on a small track (top video). The ESC is turned all the way down and I'm not on the throttle. Let me know if you want the pair.

_____________________________

I help run RC XRAY, an online store where XRAY fans buy their RC cars & kits.

Hide Signatures

(in reply to fisheydude)

Post #: 437

RE: Xray M18T and M18MT RTRs! - 1/23/2009 4:52 PM

pete2222

Posts: 134
Score: 100
Joined: 9/12/2004
Last Login: 11/12/2009
From: KentEngland, UNITED KINGDOM
Status: offline

Well, I got the CC sidewinder 6800KV package and I run it with NiMh intellect batteries. There is definitely a big increase in top end speed compared to the brushed motor. To get it to fit, I had to buy a new motor mount. One of the blue atomic ones, which is good so far and also some new mount screws for this. Also had to get some deans connectors. Although I'm really happy with it all now, I would question whether the upgrade is worth all the extra cost. It’s a lot faster, but I wouldn't necessarily say it's any more fun than before. In reterospect, for me, I think maybe it would have been better to spend the the money on another buggy/truck instead.

Hide Signatures

(in reply to fisheydude)

Post #: 438

RE: Xray M18T and M18MT RTRs! - 1/23/2009 9:42 PM

fisheydude

Posts: 219
Score: 100
Joined: 12/19/2007
Last Login: 1/16/2010
From: bowling green, KY, USA
Status: offline

RC Huligan: thanks for the offer. I know you have probably taken care of it but I am wierd about used stuff, I prefer new. I am looking at another mamba combo for my e-maxx so I thought getting this small scale stuff new would be a good learning thing.

pete2222: Where did you find those new mount screws? Would they be at a hardware store? I have had issues with trying to find strange shapes and sizes for other rc stuff that were knock offs. What connectors did it come with? I would change them over to the high current traxxas connectors to match with my other stuff if you don't have options to chose from. As far as a questionable upgrade, that is good to know. It's just that my esc has gotten wet and partially works sometimes and the last time I drove it, it would go reverse full throttle with no forward. It is a good excuse to get a more efficient system. That is what I am really looking for, run times and efficiency. The last thing I need is another money hungry rc car!

I am confused about the castle site though, did you get yours from this page:
http://www.castlecreations.com/products/sidewinder_micro.html
I just don't see a "CC sidewinder6800KV" and what is up with the web site saying "SWM/CM2054"? I assume that is the 5400KV system I want? Well, I see SWM side winder micro but what about the other stuff. I am getting confused.

_____________________________

If it''s a monster truck, drive it like a monster truck!

Hide Signatures

(in reply to pete2222)

Post #: 439

RE: Xray M18T and M18MT RTRs! - 1/23/2009 9:58 PM

RC Huligan

Posts: 372
Score: 100
Joined: 12/15/2007
Last Login: 1/31/2009
From: Charlotte, NC, USA
Status: offline

quote:

ORIGINAL: fisheydude

RC Huligan: thanks for the offer. I know you have probably taken care of it but I am wierd about used stuff, I prefer new. I am looking at another mamba combo for my e-maxx so I thought getting this small scale stuff new would be a good learning thing.

No problem. I completely understand because I'm the same way. That's why I've priced it low. Enjoy yours. The extra speed will drop your jaw the first time you pull the trigger.

_____________________________

I help run RC XRAY, an online store where XRAY fans buy their RC cars & kits.

Hide Signatures

(in reply to fisheydude)

Post #: 440

RE: Xray M18T and M18MT RTRs! - 1/24/2009 12:00 AM

pete2222

Posts: 134
Score: 100
Joined: 9/12/2004
Last Login: 11/12/2009
From: KentEngland, UNITED KINGDOM
Status: offline

hey fisheydude

I go the mount screws (to fit the atomic motor mount to the chassis) from www.boltmeup.com
1 x M2.5 x 6 Stainless Slotted Cheese Hd Machine - 20 pk - Freepost = £3.95

I got the motor and esc from
http://www.b-p-p.com
CC-SW18-2068 Castle Creations Sidewinder 1/18 Scale Motor/ESC Combo
cheap, but very slow to arrive

The esc doesn't come with connectors. you solder on whatever you like.
you can see some pics and vids here
http://www.m18mt.blogspot.com/

Hide Signatures

(in reply to fisheydude)

Post #: 441

RE: Xray M18T and M18MT RTRs! - 1/24/2009 5:42 AM

fisheydude

Posts: 219
Score: 100
Joined: 12/19/2007
Last Login: 1/16/2010
From: bowling green, KY, USA
Status: offline

Thanks for the screw details. Being you are overseas (from here) I will have to find those here somewhere, but at least I know exactly what I need. The BPP place only has the 4200KV in stock, it does look like a good price though. Would the 4200KV be too low? I guess I did say I wanted better low end but will that kill the top end compared to the 5600KV? Very nice pics and vids by the way. It looks like the 6800KV is fast!

_____________________________

If it''s a monster truck, drive it like a monster truck!

Hide Signatures

(in reply to pete2222)

Post #: 442

RE: Xray M18T and M18MT RTRs! - 1/24/2009 9:46 AM

pete2222

Posts: 134
Score: 100
Joined: 9/12/2004
Last Login: 11/12/2009
From: KentEngland, UNITED KINGDOM
Status: offline

I don't really understand how the 4200 would differ from the 6800, perhaps someone else could explain this. I guess with the appropriate gearing you could get it work to your satisfaction.

If you definitely want to go brushless, though I can tell you the 6800 isa good choice (as you can see from the vids)

Hide Signatures

(in reply to fisheydude)

Post #: 443

RE: Xray M18T and M18MT RTRs! - 1/24/2009 3:00 PM

patatchim

Posts: 124
Score: 100
Joined: 6/5/2006
Last Login: 3/19/2010
From: pt, PORTUGAL
Status: offline

pete2222 , From 4200kv, to 6800kv, thats rpm per volt, so the 6800 will spin faster. And supposedly it will have less torque than the 4200kv.

lower kv more torque, more acceleration, lower speed.
higher kv less torque, less acceleration, higher speed.
...Supposedly.

_____________________________

hk-t500;Mini titan;mosquito | 1/16 slash brushed ; wheely king | in the shelf: Tl-01b;Rc18b ;Xray m18mt;

Hide Signatures

(in reply to pete2222)

Post #: 444

RE: Xray M18T and M18MT RTRs! - 2/3/2009 9:39 PM

Mr. Mugen

Posts: 7906
Score: 122
Joined: 3/24/2006
Last Login: 3/21/2010
From: Bottom feeder feeder #1 pooper, MI, USA
Status: offline

Hey if anyone wants a free chassis PM me. It is part number 381100 and is for either a M18 or M18t or the like. I have no idea why I bought it but right now I am cleaning the shop and getting rid of stuff no longer needed.

Oh yeah it is still sealed in package too.

Kevin

_____________________________

Everything electronic runs on smoke.....if you let your smoke out, it''''''''''''''''s dead!

Hide Signatures

(in reply to patatchim)

Post #: 445

RE: Xray M18T and M18MT RTRs! - 2/15/2009 9:40 PM

smgraph

Posts: 2
Score: 100
Joined: 12/10/2007
Last Login: 9/22/2009
From: Indianapolis, IN, USA
Status: offline

Stupid ?, Can someone tell me what would it take to convert a M18pro to a M18T monster truck? Is it just bigger wheels... Thanks

Hide Signatures

(in reply to Mr. Mugen)

Post #: 446

RE: Xray M18T and M18MT RTRs! - 2/16/2009 12:35 AM

patatchim

Posts: 124
Score: 100
Joined: 6/5/2006
Last Login: 3/19/2010
From: pt, PORTUGAL
Status: offline

smgraph , from the m18t, to the m18mt, just add 4 more shocks, and to more 2 shock towers (rear and front) and thats it. Also the m18mt doesn´t bring the anti roll bar.

I thinks thats all, maybe some body posts but, not so shure...

_____________________________

hk-t500;Mini titan;mosquito | 1/16 slash brushed ; wheely king | in the shelf: Tl-01b;Rc18b ;Xray m18mt;

Hide Signatures

(in reply to smgraph)

Post #: 447

RE: Xray M18T and M18MT RTRs! - 3/19/2009 5:22 PM

maybelater29

Posts: 631
Score: 100
Joined: 11/22/2007
Last Login: 2/2/2010
From: South Park, PA, USA
Status: offline

I've been running my M18MT for about 15 months and for the first time the rear lower arm popped off the hub carrier....Do I need to replace the arm or the pivot ball...or should I just do both? Also how would the nickle coated ones help?

_____________________________

Tek18 / M18MT / Tailwhip / E-Maxx / Micro-DT

Hide Signatures

(in reply to patatchim)

Post #: 448

RE: Xray M18T and M18MT RTRs! - 3/20/2009 2:30 AM

fisheydude

Posts: 219
Score: 100
Joined: 12/19/2007
Last Login: 1/16/2010
From: bowling green, KY, USA
Status: offline

When that started to happen to me, I put small washers on the bottom to hold them on (as per advice of the fine fellows on here). Chances are they both wore down evenly so do both if anything. IMO

_____________________________

If it''s a monster truck, drive it like a monster truck!

Hide Signatures

(in reply to maybelater29)

Post #: 449

RE: Xray M18T and M18MT RTRs! - 3/20/2009 8:56 PM

DarkHorse

Posts: 339
Score: 100
Joined: 4/22/2005
Last Login: 3/21/2010
From: Gloucester, UNITED KINGDOM
Status: offline

If they are not to worn then a washer will do for quite a while but eventually they get so sloppy the straight line steering becomes difficult (after prolonged bashing in dirty streets etc.). Then you really need to replace the arms and balls (3 per arm). Not sure if it's economic to get nickel balls, might as well get a Pro kit and get lots of hop ups in one purchase

(15mm longer).

I managed to scavenge enough to change all the arms and balls on my Hummer basher this week (from last year's action damage) but I have a pretty large amount of spares and bits to draw on.

_____________________________

DarkHorse RC: Hornet X-3D, Ecureuil, Airworlf, X-ray M18T, Power & Setup Calculators ;) http://dhrc.rchomepage.com/

Hide Signatures

(in reply to fisheydude)

Post #: 450

Page: << < prev 11 12 13 14 15 16 17 [18] 19 20 next > >>

All Forums >> RC Cars, Buggies, Trucks, Tanks and more >> 1/16th, 1/18th, Mini & Micro RC Cars >> RE: Xray M18T and M18MT RTRs!
Page: << < prev 11 12 13 14 15 16 17 [18] 19 20 next > >>

Jump to:

Google

Search | Marketplace | Event Calendar | Local Clubs | Magazine | Product Ratings | New Products | Discussion Forums

Photo Gallery | Instructor Search | Field|Track|Marina Search

Advertisers | Hobby Vendor Resources | Rate Manufacturers | Sign In/Sign Up

SITE MAP! : : FORUM RULES

© 2001 - 2007 24-7 RC, LLC, all rights reserved.

Charities we support that also need your help
Yorkie Rescue | Humane Society | ASPCA | Crohn's-Colitis America

1.791RCU1