Brushless hpi baja rc-monster

[thomatrix]

Very nice. I am wondering if this can hold a Lehner 3060:


Any thoughts Mike?

I have two bajas that I want to try it out on. I've got what I need for one of them but now I am trying to figure out if I can mount a 3060 Lehner on the other one.

[mohanjude]

OK guys I got Mike's conversion last night when I got back from work.

Took me about 2 hours to almost finish the conversion. All I got to do to run the truck is to attach Speed Controller (Shulze 40.160) to the Lehner 3060 7 turn motor.

The Polyquest 5S 6000ma packs sit 'perfectly' in side the battery tray and should be good to run the setup (10S 6000ma)

Got a 23 tooth pinion coupled to the Lehner. The Lehner sits perfectly on the motor mount. The wires will need to sold from the side as there is not much clearance from the 'bullet' female connectors on the motor.

This is another 1st Class Conversion Mike has done. Everything went really smooth - all the holes aligned perfectly.I had to shave off a bit of plastic behind the spur where the bearing is held onto the brake assembly. I also took of the brace behind the fuel tank as it fouled the batteries. I had to install some washers to take the gap of the brace.


Here are some pics





Lipos and Motor




Close fit of lipos




Pinion and spur



Close up of Lehner 3060



Rear view - space on plate for speed controller

[thomatrix]

I just added your setup to the top speed calculator and it seems like you are heading for a somewhat agressive top speed. Is this correct or did I miss something. A 7 turn 3060 is 1000kv right?

[mohanjude]

Originally Posted by thomatrix

I just added your setup to the top speed calculator and it seems like you are heading for a somewhat agressive top speed. Is this correct or did I miss something. A 7 turn 3060 is 1000kv right?

Yes you are right - it was like a crazed animal. I took the pinion down to 20 and it handles better and the Schulze is less warm. It wasnt boiling hot but it was getting warm. I can only get the throttle to about 30% before the Baja starts to spin around due to the speed. I am going to take it off the tarmac and try it on a reasonably muddy surface to see if it helps with control. Not a big fan of grass but if I cannot control the car at high speed on tarmac it will have to go on grass.

I had to 2 spare Lehner Brushless 3060 Motors (7 turns) with me. Therefore I wasnt going to buy another Castle 2215. I may reduce the pinion down to about 18 - at present I cannot find my box with the Mod 1.5 pinions... so I am going to try this gear ratio for now with a 20 tooth.

I will try and get a video of the Baja later.

Mohan

[nitrostarter]

Originally Posted by mohanjude

I had to 2 spare Lehner Brushless 3060 Motors (7 turns) with me. Therefore I wasnt going to buy another Castle 2215. I may reduce the pinion down to about 18 - at present I cannot find my box with the Mod 1.5 pinions... so I am going to try this gear ratio for now with a 20 tooth.

I will try and get a video of the Baja later.

Mohan

Sounds like fun Mohan! You should definitely get some video! Those big Lehners are definitely powerful!

Btw: if you have a spare Lehner sitting around, I can find a use for it...

[mohanjude]

OK guys here is the Video - very short but it shows what the Baja is capable about and how bad my driving is....

I installed a Garmin GPS - as you can see it was reset to 0mph and got to 60 mph in a short burst. I am certain that I did not go past 1/2 throttle max due to my morbid fear of crashing onto the raised pavement slabs.

I will take it out to a more open space and hopefully open it up.

[RC-Monster Mike]

Looking good, Mohan. Don't forget to install a screw on the non-spur side top brace(mising in the pictures). I actually cut the middle of the cross brace off on my baja and kept the "ends" for spacing. Threadlock is your friend on the metal to metal attachments, too(the top brace, motor mount and brace plate, and lower plate connections specifically). That is a quite aggressive setup you have there, too(10s, 30 series motor, big pinion) - I hope you have a lot of space!

[mohanjude]

Originally Posted by RC-Monster Mike

Looking good, Mohan. Don't forget to install a screw on the non-spur side top brace(mising in the pictures). I actually cut the middle of the cross brace off on my baja and kept the "ends" for spacing. Threadlock is your friend on the metal to metal attachments, too(the top brace, motor mount and brace plate, and lower plate connections specifically). That is a quite aggressive setup you have there, too(10s, 30 series motor, big pinion) - I hope you have a lot of space!

mike

I didnt fasten the left plate securely as I had to take it off to solder the wires. I have now firmly thread locked all the screws. On the left top plate there is an empty counter sunk hole where the screw would have gone into the rubber plastic / damper fixed to the engine. it is an awkard piece - do you think I need this?

[jpoprock]

Question... My goal is to one day in the next year or so to BUY a used/hopped up 5T. But for me, the allure was the idea it runs on gas. I wouldn't have to worry about it getting wet, and could drive it anywhere, anytime.

If you go with Brushless... now suddenly you have to worry about sand, water, mud, etc getting on the ESC and in the motor. So... what's so great about going BL in something like this, other than lack of noise!?

Thanks!

[snellemin]

ESC can be waterproof and the motor and batteries can be sealed. No biggie really. Lack of noise is a big plus for me, as I currently only get to play with my stuff in the middle of the night. My neighbors would be pretty pissed if they heard a lawnmower go off at that time of night.

[thomatrix]

mohanjude,
excellent video. Would really like to see a video of that beast running at max throttle...

What is your experience with the Lehners - are they worth buying for this kit? I am thinking of trying a 438kv 3060 with a 12S setup. I have 17-20 pinions that would fit this setup. Let me know your thoughts.

I already have on kit ready with a 750kv 2215 Neu motor that is going to run 10S config but I have been quite keen on trying a Lehner for some time and now it seems doable :)

[mohanjude]

thomatrix

My first ever brushless motor was a Lehner way back in 2002 for a emaxx. My jaw fell off when the e-maxx screamed on a simple 16.8v nicad setup. No Lipos those days. It gave my t-maxx 1.5 a roasting.

I love the Lehners but find them very pricey compared to say Castle. Hard to get hold off one unless you go to the factory website. But these motors are really efficient and spool up quickly.

I would always recommend Lehners if you can afford them. I think Castle / Neu are brilliant motors too now that they are making different can sizes. If you go with your setup you will have plenty of run time but compromise on speed. I am a speed junkie and that is why half the time I convert everything to brushless.

The Lehner fits perfectly on Mikes motor mount. the biggest motor will be 3060 - I have a 3080 and it is too long to fit.


mohan

[RC-Monster Mike]

Yes, I think it is wise to use the left countersunk screw - the wierd angled molded plastic piece can simply be trimmed with a dremel for clearance. IIRC, the screw is an M5 or M6 with a lock-nut on the bottom side - this will add significant support to the top plate, as the next closest screw holding the top plate own is all the way at the rear of the bulk.

Lehner motors are excellent, though expensive and poorly backed in the service department in my opinion. 4 pole is better in the Baja specifically IMO as well(more torque at startup/smoother startup in sensorless operation and the Baja ha a fairly high rollout).

In electrics bigger motors are for bigger constant loadings these cars have relative light duty cycles.

I am wondering if any of the talk about the bigger motors has taken into account the efficiency spread and torque output on those motors are; how they stack up in terms of power to weight and how efficient they are at the loads the car runs at most of the time?

There seems to be a lot of assumptions made that relate to fossil fuel ie bigger is better. Bigger electric motors arent better, they are heavier, they are more expensive and they may deliver ordinary results with more wear on other components.

Electrics are fast when there is lots of voltage, a light efficient motor and a tough esc. IME the Neu 2215 is a max for a car this size - it easily over powers it and is faster than petrol motor

[RC-Monster Mike]

Light duty cycles relative to what? I do agree with the premise of what you are saying and agree that there can be a tendency for slight overkill, but there is also fairly good reasoning behind this mantra. While average loads throughout the run may be fairly low(30 amps constant with 8s in a Baja is about 1 HP), the peak draws can be significant(5-6HP peaks have been logged on mine with a 1527 Neu motor). The high peaks yield fairly low efficiency for the short burst periods, which can generate some significant heat as they happen constantly(constant intermittent loads). The larger motors can simply dissipate the heat faster due to larger surface area, which can make them "seem" more efficient, but also can allow them to sustain better efficiency with the lower heat. When we are dealing with a couple to a few hundred dollars spent on a motor for the Baja, it means a larger motor, while perhaps not as "ideal" in some respects, is likely to run cooler and therefore less likely to fail. A larger motor is also theoretically less susceptible to thowing a rotor from the shaft when landing a jump or similar shock to the drive train, simply beacause there is more surface area at the magnet/shaft interface(I have thrown one rotor on my 1527 motor already).
I will likely continue to run the 1527 motor in mine, as I like the runtime, power and size, though I have added some heat sinks(2 Losi heat sinks fit perfectly and add a LOT more heat disipating surface area) and will add a fan if I need more cooling. If not for the heat sinking, I could easily overheat this motor and cause failure(and it is very close to a 2215 motor in overall size and power output), which is why people will tend to err on the side of "overkill". Likewise, if I ran back to back to back packs with this or a 2215 motor without cooling consideration, heat would likely win the battle - so a 2230 motor, while technically "overkill" for the task at hand, is likely to handle multiple packs on a hot summer day better than a smaller motor could.
Basically, I agree to a point, but also can respect and understand the reality of the situation and the reasoning behind it. sometimes bigger really is better(to a point). :)