Help recommend a cheaper 1000kv motor
 

Hi guys... just looking around for a cheaper motor to test as an alternative to a 1527 2.5d from castle which is $300.00

Looking for a solid motor that can handle a truck of around 20lbs or so.

I was looking at leopard motors, but wondering if anyone knows of any other brands and have had good results with???

Thanks

Josh

I looked around and the Leopard 5682 was the only other good option I found to the 1527 - that's why I decided on the 1717 for my next build - it's almost as heavy as the 1527 (20oz vs. 21.8oz) so I figure I can push it a little and see how it works.

http://www.rc-monster.com/forum/showthread.php?t=29657

Brian, thanks again for the help and advice.

I am just annoyed that the 5682 has a 6mm shaft on it. I guess it could work well... and a mate of mine loves his 2000kv motor in his XXL flux too. Says it always runs cool.

I could run this motor nicely on 10s as well which would be beneficial...

I do not want to get a 1717 although it is a very good motor, just because i am not able to run 8s and even 8s is a push.... I bought a 12s esc wanting to run 9s or more preferebly 10s. (i thought 12s would be uncessary in terms of adding lipo weight.

Honestly though... i am not sure if i could even fit the length of a 1527 in my chassis... as my new TVPs havent arrived and i cant mock things up just yet....

Also i am not sure, but is the leopard 5682 as fat as the 1527?

I was looking at this 1000kv leopard motor which has a 5mm shaft as yes is a little smaller... but is described as a motor for heavy 1/8 or lightweight 1/5 which i believe my savage falls into???

What do you think?
http://www.himodel.com/electric/LEOP...BP4082_3Y.html
http://www.himodel.com/img_sub/rc_img/10/08/7497.jpg

The 56 series leopards are as fat as the cc 2028, just not as long. They are 5th scale motors, and i doubt they will fit your application. The 1717 is 45mm diameter, and the 56 leopards are 56mm diameter.

The 4082 is about the physical size of the castle 1518 motor, not quite as long as the 1520. For the price I would give it a try. The 1000kv model on 10s should work fine.

cheers linc... WOW didnt realise the 56 series were so huge!!! Lucky i didnt get one! No way would that have fitted, and even a 1717 would be a little tough!

I feel silly for asking this...

But if a 4082 leopard is the same size as a 1518 and smaller than a 1520. How would it be able to perform better than a 1520 on 9s?

I think i need a short explaination as to how Kv actually works... Wouldnt the smaller 4082 generate a lot of heat as it is such a small can?
Due to the length of the 1520 can, maybe it will be able to handle 9s quite well?

Thanks

Josh

Yeah, I think you're better off with the 1520 than the leopard 4082. You're trying to move a big, heavy truck - so the bigger the motor the better. The kv, to me, is secondary to the size of the motor - the right kv will allow you to use the appropriate voltage and gearing for your application.

If you can't run a larger diameter motor (like the 5682) then I think your best bet is the 1527 if it will fit.

Hmm, well I do not really think that there is a huge difference between a 1518 and a 1520 motor. The rotor is 2mm longer. The kv is 200 lower on the 1520 cc motor, and it is just right for 6s in most 1/8 applications. Not sure why cc made the 1518, as a 1515 is pretty versatile.

Now I am only going by external dimensions. Until someone measures the leopard 4082 rotor and windings I can only guess that it is similar to a 1518. It may be closer to the 1520, who knows.

Going by max motor rpms, figuring 3.7v per cell under load:

A 1520 1600kv on 9s is 53280rpm

The leopard 4082 1000kv on 10s is 37000rpm, on 12s - 44400rpm

Given your center diff setup, diff ratio and tire size you will have a hard time gearing the 1520 down enough to have sane speeds.

Depending on what max motor speed you may be able to go to the 1250kv leopard on 10s.

You have a difficult situation to balance here. You have a heavy vehicle and limited gearing options. So you want a motor powerful enough to move the truck but you do not really have the ability to run really low gearing and a fast spinning motor.

I would say to go with the largest motor you can to fit the space. Pity leopard do not make a 90mm or so long motor in the 40 series. That would get you close to a 1527 in dimensions.

9s on the 1520 may be spiining that motor past its efficiency window, so it may get hotter than the 4082 on 10s running at a lower rpm.

Since he has the 1520 and lipos are now pretty cheap (compared to a few years ago) I think he can try the 1520 and see how it does.

He can pick up 2 5s packs and a 4s for testing. If he stays with 9s he can just buy another 4s pack and have 2 sets of batts for the truck, or sell the 4s off and get some money back if he sticks with 10s and another motor.

I do agree that the 1527 would be best. However that motor will cost more than the leopard and all of the lipos combined.

yes you are both right... im having a hard problem gearing right...

I wouldnt have a problem if i was running my Maxx sized badland tyres as i can gear it just right. But with the baja tyres increasing my roll out, makes things very difficult.

Choosing an adequate motor is proving difficult... the 1527 is perfect. But after the amount i have dropped on the savage already, i need to delay the motor for now. i will most probably pick one up at some point in the future. But right now i cannot.

My 1520 has literally had 2 runs on it. Trying to keep it as fresh for this build as possible :)
I would run 8s, but that is not an option just because i am being stubborn. If i wanted to run 8s, i would have gotten the 8s XL controller.

I will be running 2 3s lipos in battery boxes on the side of my savage and then have space for up to a 6s lipo in my rear tray... So i have a lot of flexibility.


I have been very impressed with the 1520 so far. It doesnt get above 140F on a 16lbs savage geared for 56mph on 6s and that is me doing speed runs back to back.

So if i gear the truck down to a 10t pinion (yes it is small) with the baja tyres i get a top speed of 48mph on 6s... and on 9s i get 70mph. I do not see a problem with this, considering this is what i used to do with my 2200kv motor and switching between 4s and 6s and keeping gearing the same.

The truck will be designed for general bashing and large open spaces as there is no reverse. I will prob never use prolonged WOT situations but i believe we under-rate this motor. It has been impressive so far!


Once i have everything mocked up in my chassis, and i know how much space i have to play with for a motor, then ill see... but how it is looking I will probably stick with the 1520 for now, and work out a way of running a 10t pinion (at the moment i have a 12t pinion on there but i will struggle to get a 10t on because my brake system is in the way :-/ and im struggling to get the motor close enough for a decent mesh.


If it blows... ill look into the 1527 or leopard...

BUT i have a question... If my motor blows a rotor... Will my ESC or lipos sustain any damage? I can afford to lose a motor, but not all my electrics!


Guys! Thanks a lot for your help! Appreciate the fast replies!

edit: I will run this on 8s occasionally as i have 8s worth of hyperion g3 6500mah lipos :)
i will use 40c turnigys for 9s as they are so cheap

What brand of pinion do you plan to use?

I have had very good results with novak. Last the longest soo far and very well priced.

I agree that the 1520 on 9s or 10s may be too much. I guess what I'm saying is that I'd go with the biggest motor that can fit (since this is a big truck that needs a large motor) and then choose the appropriate voltage and gearing. Rather than deciding on a voltage first (9s-12s), all of the factors (kv, voltage, gearing) need to be considered. So I might go with the 1520 on, say, 6s-8s over the 4082 on higher voltages.

I think the leopard 4082 1000kv on 10s and the 1520 on 6s would be comparable power output.

Now the leopard 1250kv 4082 on 10s might have an edge over the 1520 on 8s. Not sure, probably be close.

Given his setup i would go with a 1717 motor on 7-8s. The power output of a 1717 is somewhere between a 1521 and 1527 neu. The 1527 would still be the best fit, and would allow for lower motor speed and a larger pinion to help with gear wear and overall durability.

A good setup would be the leopard 5682 910 kv motor. Large diameter so lots of torques and 33k rpm on 10s. Slightly shorter than the 92 motor so not as huge power output. Might be able to get the motor far enough from the spur as larger pinions would be used to make up for the slower motor speed...

Jahay, what size spur are you using? And what brand or type of center diff?

And what is the smallest pinion and spur you can run to clear the mech brakes with the 1520?

Firstly Linc,

Im running an ofna 6 spider centre diff with 47t spur. Currently the smallest pinion i can fit is a 12t pinion, maybe an 11t just about. But if using the 1520 i NEED to use a 10t at most!
This means i would need to make alterations to my custom motor spacer. Not much work needed, but it is required to fit a 10t pinion.

If i ran my maxx sized badlands, i could theortically run a 12t-13t which wouldnt give me any of my current problems.

Brian - i know my method of choosing voltage over motor etc... is not correct. But i am determined to run 9+ cells of lipos. If a new motor is necessary, then so be it.

Imo i think 9s is too much and 8s would be ideal on a 1520... But, in short... I would prefer to push this motor to its limit and see what it can really do (i have second one as back up anyway :) )

I do think a 1717 would be an ideal motor for me... but as said previously... shame it is not capable of handling more cells...

Put it this way... i have been trying to do something different to most here in the UK... everyone now has a 1717 or a 1520 running on 6s or 8s thanks to the new MMXL.... but no one is running anything bigger... So this is my pursuit... I have spent a lot of money on this build so far, and would like to keep it a different. I WISH I COULD GET THE 1527, but that isnt possible just yet...

The 5682 would be ideal for the price... and i doubt i would stress it much as it was build for heavier applications... BUT if it is the same size as a 2028 motor for a baja... then i doubt it will fit in my chassis, let alone work with my current motor mount which i had custom built.....

I don't know all of the particulars, and don't feel like using the speed calc at the moment to see how much difference it'll make, but Ofna does make a 48T spur for the spider diffs. Part #OFN19345

Edit: I did just visit BrianG's site to figure out the diameter of the Spur gear and it says the 48T will be 1mm bigger in diameter than the 47T. But thats diameter, in reality the spur will only be .5mm closer to the pinion.

Ok, well crunched some numbers for ya.

To fit the 56 series motor in you need to move the centerline of the motor 7mm away from the current location with 47/12 gearing. Does your mount have that amount of slot length avaialbe?

That does not really matter, cuase you would need a much bigger spur to get gearing right if you ran 1000kv motor on 10s. A 62t spur from the old jammin crt would work, with an 11t pinion. That will place the side of the 56 leopard right up against your mech brakes, just as the 1520 is sitting now with the 12/47 gearing. However with a 6:1 ratio that pinion is not going to last very long. Any you would be geared for low 40s. So you could go up to the next higher kv, 1250. That would give you low 50s with your 6.88 tall tire and bp diffs. Or you can go to a 14t pinion, but you are running out of motor mount adjustment then.

The 62t spur is a feeris wheel, but when you run low ratio (numerically) diffs and no tranny you need some reduction somewhere.

Heres the numbers:

1520 = 42mm dia - 21mm rad
56 leopard = 56mm dia - 28mm rad

7mm diff

47/12 gearing = 31.5mm between centerline of gears

Add 7mm = 38.5 to fit the 56 leopard and have the can as close as you have the 1520.

Jugle the numbers on BG's site and with a 62t spur you need an 11t pinion to get 38.5mm between the centerlines.

A 52/21 would also work, but with less overall reduction you would need a much slower spinning motor. Not sure if you could run a very low kv 56 size motor in there. Around 600kv would work, but the load on the motor will be very high.

Thanks linc for doing the crunching... really do appreciate the help!

So...
Yes i do have the 7mm adjustment needed to push the pinion away from the spur due to the larger motor can....
BUT
i do not think that the larger 62t spur you are talking about will work with my ofna spider diff... and OVERDRIVEN, i dont think that 0.5mm will make enough of a difference with y current situation.... I think i did see a 52t somewhere, but i am unsure about that....
But i am worried, that if i use a spur which is too large, it will then hit my top plate on my diff mounts....

Linc, just out of curiousity, will the 56 motor have similar mounting points as the castle motor?

I am now considering turning my motor/diff mount 180 degrees now, and have the motor mounted at the rear and somehow mount the 3rd lipo up front. This would give me more space for a larger motor as i have plenty of space in teh rear.
AND
I wont have any problem clearing my front brake mech. I will just not run rear brakes and i can run what ever pinion size i like and mesh as close as i want.

But i cant work any of this out till my Chassis arrives from GCM....

Linc thanks again!!! i will update this thread when i know more about the space i have to work with....

Im not even sure if the motor will sit right when mounted to the motor mount.... because it will be too fat and hit off the side of the tvps?

You will see what i mean...

Not likely, the 56 leopard has m4 thread holes 30mm apart.

Yeah, post some pics when the chassis comes in.

It would be pretty easy to figure out how big of a spur gear you can put on your CD without it hitting the top plate. BrianG's page has a gear calculator, just need to measure the amount of clearance you have. Another option is a custom top plate that has an opening (slot) in it for the spur gear. The top plate would have to be wider to accomodate the spur gear slot and still connect the diff mounts together, but it would do the job and support both front and rear brake cams.

Yes... i could get one made up. Dejan already has my top plate measurements etc..

But i dont think the Spider Diff works with anything other that a 52t...I havent seen anything bigger as of yet...