My First E-Dune Runner

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I'm hoping to get near 25mins. The 1/5 scene here hasn't been organized enough to get consistent racing going. It's more like organized practice w/ organized 6 min runs.

I have calculated the hp but I'm going to try and tone it down to about 4hp to keep everything together. Speaking of staying together, I have made a little progress on the bracing needed for the rear of the chassis. Maybe tonight I'll get it done w/ a picture.

The 8000mah batteries (that hopefully show up this week) have me a bit worried about their size. From the online dimensions, I might have to move the servo tower forward a half inch and completely remove the radio box.

And we're still waiting for the esc in customs :(
 
Thats cool, just racing with friends counts for me as racing. Generally its 20 minutes for gas 1/5 buggy and 30 minutes for trucks from the large events I saw. 25 min is a good benchmark. We can not enter our ep cars at most events yet, but at least they will let us run for fun.

That sucks your waiting so long for the esc, customs blow lol. Hopefully your goodies come in sooner than later.
 
Good news, the ESC just showed up today. The tracking was way off. Hopefully tonight I can get the ESC wired in. The wires on it are huge.
 
I was able to wire up the ESC and run it on 10s. By the time I got to this point it was dark out and my street has no lights. So you could imagine my tentativeness to run the car very had. But w/ limited site and distance I managed to get it up to 30mph. I'm sure 12s will be more than I need.

The car seems ridiculously fast for such a large car. The power is instant and comes on like crazy.

I only ran it sporadically for about 8 mins and the temps seemed a little higher than I had hoped. The motor and esc were 120F and the batteries were 100 and outside temp was 98F. I know I cannot lower the gearing anymore but maybe I can free up the drivetrain some. It has so many moving parts that it's just not efficient.

I do have the programming card for the ESC which I'm hoping to use to tame the esc a little. I'm also curious about a tighter clutch spring so it kicks in at higher RPM's, anyone know of one?

And I weighed it w/ 12s, it's 28lbs rtr. I really thought it would be more. I'm pretty sure my batteries and motor weight more than the original engine and tank(full).
 
I do have the programming card for the ESC which I'm hoping to use to tame the esc a little. I'm also curious about a tighter clutch spring so it kicks in at higher RPM's, anyone know of one?
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They come with a 6000rpm from the factory. Available are also 7500, 8000, & a 9500rpm.
 
And I weighed it w/ 12s, it's 28lbs rtr. I really thought it would be more. I'm pretty sure my batteries and motor weight more than the original engine and tank(full).
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Your coming in lighter than if you were gas powered.
 
mulepic said:
I was able to wire up the ESC and run it on 10s. By the time I got to this point it was dark out and my street has no lights. So you could imagine my tentativeness to run the car very had. But w/ limited site and distance I managed to get it up to 30mph. I'm sure 12s will be more than I need. The car seems ridiculously fast for such a large car. The power is instant and comes on like crazy.

I only ran it sporadically for about 8 mins and the temps seemed a little higher than I had hoped. The motor and esc were 120F and the batteries were 100 and outside temp was 98F. I know I cannot lower the gearing anymore but maybe I can free up the drivetrain some. It has so many moving parts that it's just not efficient.

I do have the programming card for the ESC which I'm hoping to use to tame the esc a little. I'm also curious about a tighter clutch spring so it kicks in at higher RPM's, anyone know of one?

And I weighed it w/ 12s, it's 28lbs rtr. I really thought it would be more. I'm pretty sure my batteries and motor weight more than the original engine and tank(full).
Click to expand...
The stock spring engages at approximately 6000 RPM. You have a few options...

DDM Premium 7500 High-RPM Clutch Spring for Zenoah / CY Engines

High Response Clutch Spring Set 8000 RPM

DDM Premium 9500 High-RPM Clutch Spring for Zenoah / CY Engines
 
Thanks for the info. Maybe I'll try the hpi spring since I can get it at tower and I need some other things from there too.

The YEP 120A esc is supposedly a re-branded YGE and in fact I had to use the YGE instructions to set it up b/c the esc came w/ none. The programmer is the same as well.

After reading about the YGE it became clear I need a heat sink. Since I also need to come up w/ an ESC mount I figured I'd create a mount that is also a heat sink. It'll be a good chunk of aluminum but the idea is to suspend the ESC in the windshield area of the buggy at a slight angle to let the air flow through the fins of the heat sink. It'll be slightly offset to the right to allow air to flow to the motor as well.

The motor will probably be another project. I could envision a wind scoop in the back of the roll cage directing air over the motor b/c right now it sits a bit low and heat build up could be an issue.
 
Here is the start of the heat sink. :) No one ever said a heat sink is too big.

I need to cut slots on the side for some velcro straps. And I need to cut slots for air to flow through and increase the surface area. It'll be the aluminum that faces the front of the car. Right now I'm envisioning a piece of angle aluminum will be mounted to the top of the center diff and elevate the ESC into the windshield area.

7881306174_b54790852d_z.webp
 
That is a great idea. Its been fun to follow your build. You seem to have a plan and overall idea of your final product. Your not just wing'n it.
 
Thanks, I wish I could say that. I'm just learning how to make my mistakes not look like mistakes ;)

Here is a progress shot of the heat sink. I might put some more cuts in it but I need to save material on the sides to drill/tap and mount the esc.

To give you an idea of the sizes. The ESC is 2" x 3" and the heat sink is 3.5" x 3"

I'm hoping this really helps keep the esc cool.

7882784958_745e6c5430_z.webp
 
That looks great! I have to ask. Do you do machining for work, or are you lucky enough to have a CNC at home?
 
RCDAD said:
That looks great! I have to ask. Do you do machining for work, or are you lucky enough to have a CNC at home?
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No, I'm not a machinist, but my father was. I always wanted a milling machine for the longest time so finally at the beginning of the year I bought one. It's the harbor freight knee mill that is red. I used the 20% of coupon (which they actually have going on now) online and it was at my door in less than a week. It's been worth every penny.

A CNC would be fun but I'm pretty sure I wouldn't be able to store that one in the garage. But maybe a lathe will be next.
 
All mounted up. It's not exactly as I had envisioned. I thought my angle would raise it up higher so for now it's horizontal. It also turned out to be more solid than I had thought. I was planning on fully boxing the mount.

7884030670_5c670e5668_z.webp
 
I ran the car again on 10s w/ the heat sink in place. It was hard to tell if the heat sink was doing anything. The esc is encased in shrink wrap so I had my doubts if the heat would transfer well from the esc to the sink. After a couple temp readings w/ the esc at 120 but the heat sink at 65F I took the shrink wrap off. The esc has a metal plate on the FETs that I guess is suppose to be a sink. Now that metal plate is right up against my heat sink.

I ran it some more this way and the readings were the same. At the same time I noticed my alum. angle was hotter than the sink. The diff is transmitting a lot of heat directly under the esc now. So I'm going to insert some delrin between the diff and the esc mount in hopes to reduce that heat underneath the esc.

If the temps do not go down on the esc I'll get some of that thermal paste and see if that creates better connectivity between the esc and my heat sink. Also when my batteries come in I'll be running much shorter power wires than I have now.

Speaking of batteries, they should be here tomorrow. I'm hoping I don't have to move the servo tower and radio tray.
 
mulepic said:
Here is the start of the heat sink. :) No one ever said a heat sink is too big.I need to cut slots on the side for some velcro straps. And I need to cut slots for air to flow through and increase the surface area. It'll be the aluminum that faces the front of the car. Right now I'm envisioning a piece of angle aluminum will be mounted to the top of the center diff and elevate the ESC into the windshield area.

7881306174_b54790852d_z.webp
Click to expand...
Should look cool!
 
mulepic said:
Thanks, I wish I could say that. I'm just learning how to make my mistakes not look like mistakes ;) Here is a progress shot of the heat sink. I might put some more cuts in it but I need to save material on the sides to drill/tap and mount the esc.

To give you an idea of the sizes. The ESC is 2" x 3" and the heat sink is 3.5" x 3"

I'm hoping this really helps keep the esc cool.

7882784958_745e6c5430_z.webp
Click to expand...
More slots would definitely help with heat dissipation.
 
mulepic said:
All mounted up. It's not exactly as I had envisioned. I thought my angle would raise it up higher so for now it's horizontal. It also turned out to be more solid than I had thought. I was planning on fully boxing the mount.7884030670_5c670e5668_z.webp
Click to expand...
Looks great! Very beefy.
 
Deluge said:
More slots would definitely help with heat dissipation.
Click to expand...
After doing some reading about fluid dynamics and looking at the equations that impact a heat sink's ability to dissipate heat, I can make some changes. Without making a new heat sink, I can improve the current one by making the fins taller. I was curious about this when I was making it but I errored on the side of strength. Now that it's together I can take another .025-.040" out of the base to effectively make the fins taller. Thermal paste is also important. I'll be picking some up today.

The ESC still has some adjustments I can make to cool it down too. I also read the YGE likes higher RPM's as well, so the tighter clutch spring should help.
 
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