Plasma Edge II Maiden Bash - Observations & Questions

[tomjkear 24]

I finally completed my Plasma Edge II build and gave it it's first good run this morning.  Well impressed so with it!

After some trim adjustment the car runs dead straight and has plenty of speed for garden runs.  I created another thread where we discussed a hotter motor and I actually bought a GoolRC brushless system and a 19T pinion but when I realised the car came with a "Torque Tuned" motor in the box I was interested to give it a try, along with the stock 17T pinion.  I had a Dark Impact years ago that came with a standard 540 motor and I soon upgraded to a brushless system.  This time I think the box motor is plenty good enough - main difference I'll be driving mostly in a garden instead of a large car park and field.

A few things I noticed...

Are there any tips or tricks to stop the plastic "discs" that the suspension springs sit on popping off?  I noticed a few times, front and rea,r that the spring was not sat correctly and it was just that these had moved out of place?

I also notice dmy nice new paint job, discussed it another thread, is scratching quite easily.  I can't remember if I had this issue with my Dark Impact but I've noticed right away this time.  The paint is scratching off, most notably where it runs against the under-shell body clips and the fins on the ESC.  What do you think?  A piece of table on the underside of the shell to stop the metal parts rubbing against the paint?

Finally, what is the best method for cleaning up after a run in wet grass?  My Dark Impact was a great car and put up with a ton of abuse but it's final demise came when I didn't clean it well enough and left it under my be at uni.  Parts rusted and seized up and it went on eBay as a project for someone who had the time and inclination to clean it up.  I don't want this to happen again   I've immediately brushed the majority of the grass off with a dust pan brush which has got the bulk off but there is plenty still stuck in the nooks and cranies that the brush can't reach.  Any advise would be great.

Cheers!

[speedy_w_beans 4241]

A few ways to reduce spring retainer movement:

• Add a small zip tie or O-ring immediately above it on the shock shaft (although this cuts into suspension travel slightly)
• Wrap the lower shock eyelet in a layer or two of tape for a tighter friction fit between the two parts

For the body:

• It's helpful to bend the body clips so the "head" and "tails" are no longer horizontal.  For inner body clips, bend those segments down but leave the middle flat.  For the outer body clips, bend those segments up and leave the middle flat.  It also makes it easier to remove the outer body clips later.  I use a pair of needle nose pliers to do this.
• There are several sources for foam body washers out there; these go between the inner body clip and the body.  You can also make some washers out of cardboard from a cereal box or some other material.
• Aluminum tape applied inside the body can help wherever it rubs against something.

For cleaning:

• Brushes/toothbrushes can be helpful to knock the big crud off the model.
• I've been using an air compressor with a nozzle to blast other dirt and debris out of the model.
• A damp paper tower or rag to wipe the rest of the parts down along with a little bit of partial disassembly if necessary...

 

[tomjkear 24]

Thanks for the advise speedy_w_beans.

I decided to give it another run and this time it didn't go so well. 

I noticed the car started to sound a bit odd and at first thought it was where the battery was getting low.  I popped the shell and noticed the heat from the motor has melted it's wires slightly, where they are so tightly packed against the end of the motor.  When I wiggled the wires I noticed there is also a lot of movement in the motor.  It's too hot to get a good look at the moment but it looks like the motor may have melted the plastic mount?

Edit: it cooled enough for me to handle so I opened it up and it looks like the screws into the motor just worked their way loose. I'm surprised because I did them pretty tight the first time.

I've tightened everything up again and put a tiny piece of electric tape around the wire. I'm not sure if it's my imagination or if the motor sounds louder/rougher. What do you think? Could the heat have damaged the motor? Weird it got so hot since I'm all stock. The only upgrade is bearings.

[speedy_w_beans 4241]

Lots of things to think about; that's part of the joy of the hobby.

• It's possible the motor is making more noise, but since the kit isn't that old it's not the first thing I would suspect.  I just pulled an older, used silver can motor out of my parts box the other day.  Spinning it by hand, it sounded pretty loud.  I put a drop of oil at each end of the motor, one drop per shaft/bushing location, and worked it in by pushing the shaft from side to side and spinning it by hand some more.  Virtually all the noise was gone except for the sound of the brushes sliding over the commutator inside the motor.  So, it might not hurt to pull the motor and put a drop of oil in each end.
• The kit should have included a cardboard spacer that fits between the motor and the mount.  The purpose of the cardboard is to isolate the motor heat from the plastic mount.  If the motor gets too hot and makes direct contact with the plastic mount, it might soften slightly and then the screws you tightened will appear to come loose on their own.  Hopefully you installed that piece of cardboard or fiber board or I would guess the screws will magically loosen on their own again.  There might be some value in putting the smallest amount of blue thread lock on the end of the screw before installing it in the motor, but I haven't had to do that in the past.
• When the motor loosened and pivoted slightly, maybe the mesh between the pinion gear and spur gear spread apart enough to cause some light damage to the gears.  It would be difficult to inspect and determine unless there was gross damage involved (uniform teeth become sawtooth-shaped, for example), but I doubt anything major happened.  Take a brief look at your gears but don't obsess over them.  If the kit pinion is steel (I think it is -- check with a magnet), then really the only gear that might see some early wear is the spur gear.  It's pretty much a blanket statement around Tamiyaclub to replace all aluminum pinions with steel ones.
• A little bit of heat management never hurts; if there's room next to the motor consider getting a cooling fan like one of those Yeah Racing Tornado fans and mounting it to blow on the motor.  Brushed motors can be 50-70% efficient which means 50-30% of the power is turning into heat and not mechanical movement.  Brushless motors can be up to 90% efficient and can run cooler in the same application.  But, for starters a cooling fan to force the air under the buggy shell might help a little.  Summer temperatures are more challenging than autumn/fall/winter temperatures.  It also doesn't hurt to invest in a cheap infrared temperature gauge to check the case of the motor and the heatsink on the ESC; when temperatures start climbing over 140F-160F or 60C-70C then it's time to take a break or look into gearing the car differently.

 

[tomjkear 24]

3 hours ago, speedy_w_beans said:

Lots of things to think about; that's part of the joy of the hobby.

• It's possible the motor is making more noise, but since the kit isn't that old it's not the first thing I would suspect.  I just pulled an older, used silver can motor out of my parts box the other day.  Spinning it by hand, it sounded pretty loud.  I put a drop of oil at each end of the motor, one drop per shaft/bushing location, and worked it in by pushing the shaft from side to side and spinning it by hand some more.  Virtually all the noise was gone except for the sound of the brushes sliding over the commutator inside the motor.  So, it might not hurt to pull the motor and put a drop of oil in each end.
• The kit should have included a cardboard spacer that fits between the motor and the mount.  The purpose of the cardboard is to isolate the motor heat from the plastic mount.  If the motor gets too hot and makes direct contact with the plastic mount, it might soften slightly and then the screws you tightened will appear to come loose on their own.  Hopefully you installed that piece of cardboard or fiber board or I would guess the screws will magically loosen on their own again.  There might be some value in putting the smallest amount of blue thread lock on the end of the screw before installing it in the motor, but I haven't had to do that in the past.
• When the motor loosened and pivoted slightly, maybe the mesh between the pinion gear and spur gear spread apart enough to cause some light damage to the gears.  It would be difficult to inspect and determine unless there was gross damage involved (uniform teeth become sawtooth-shaped, for example), but I doubt anything major happened.  Take a brief look at your gears but don't obsess over them.  If the kit pinion is steel (I think it is -- check with a magnet), then really the only gear that might see some early wear is the spur gear.  It's pretty much a blanket statement around Tamiyaclub to replace all aluminum pinions with steel ones.
• A little bit of heat management never hurts; if there's room next to the motor consider getting a cooling fan like one of those Yeah Racing Tornado fans and mounting it to blow on the motor.  Brushed motors can be 50-70% efficient which means 50-30% of the power is turning into heat and not mechanical movement.  Brushless motors can be up to 90% efficient and can run cooler in the same application.  But, for starters a cooling fan to force the air under the buggy shell might help a little.  Summer temperatures are more challenging than autumn/fall/winter temperatures.  It also doesn't hurt to invest in a cheap infrared temperature gauge to check the case of the motor and the heatsink on the ESC; when temperatures start climbing over 140F-160F or 60C-70C then it's time to take a break or look into gearing the car differently.

Thanks for taking the time to give these detailed answers - really appreciated.

• I put another charge in the battery and gave it another blast now everything was tighened back up.  If I dismantle again then I might take this advise!
• I LOVE following step by step instructions, so no worries I installed the spacer as instructed, including the thin trace of Anti Wear Grease to stop dirt getting in.  I considered that I might have to replace the mount or motor so I did the screws REALLY tight this time.  I thought they were tight the first time around but I might have been cautious to avoid over tightening.  If they loosen again I'll buy some thread lock (and possibly the aluminium mount).
• I looked over the gears and they looked and appeared to mesh fine.  I think I might've been lucky.
• How about the Tamiya TT02 Alum Motor Heat Sink 54571?  Are they effective or a waste of time? 

[speedy_w_beans 4241]

I never had great success with passive heatsinks like 54571; they work best if you have some airflow (which might be challenging under a buggy shell; less challenging under an on-road shell).  When I need to keep things cool I prefer fans because air flow is guaranteed.

[tomjkear 24]

17 hours ago, speedy_w_beans said:

I never had great success with passive heatsinks like 54571; they work best if you have some airflow (which might be challenging under a buggy shell; less challenging under an on-road shell).  When I need to keep things cool I prefer fans because air flow is guaranteed.

The Yeah Racing Fans look awesome but I can't find information on how to mount and power them?