Stretched e-Muggy (Baja-style) Build Thread

[Jahay]

please keep us posted with some pics on how you fit the bearings... Shame there is no space in my savage knuckles for an extra bearing

[brian015]

I finally got a chance to weigh this thing today, and with batteries it's 18.8lbs. Slightly more than I was expecting, but I was in the ballpark. My Muggy weighs 12lbs with batteries. The chassis, wheels/tires, and extra battery cells are the biggest differences between this and that (also motor and esc are a little heavier).

I landed a jump today a little on the nose and a front spindle broke near where the turnbuckle attaches - this definitely looks like a weak spot. Anyone have any luck with aluminum LST2 spindles?

[brian015]

My replacement spindle lasted one week - I broke it this morning when I rolled the truck over. I realize I'm putting more strain on it with my wheel extenders, but I still can't see how it breaks so easily. I looked at them and can't see a good way to strengthen them so I ordered some RDLogics aluminum spindles. I figure, if they break, at least I'll be able to fix them somehow.

I'm also learning more about setting up the suspension on this truck. I never really had to worry about suspension set-up before - for 1/8th bashing, it wasn't a big issue for me - pretty much anything worked. For this truck, I see that the softer/lower I make the front, the better it handles at high speeds - by keeping the front wheels on the ground, it appears. I was doing some high speed runs on the soccer field again today (I stayed away from the goal-posts!) and can really see the handling improvement. When I started out with this truck, pulling the throttle all the way meant that it would be heading in a different direction than I wanted. Now, with a little throttle control, I can get it all the way pulled and going where I want.

I'm also testing out a new esc (Ice HV 160) with data-logging, so when I get this fixed and a longer run logged, I'll post data. I'm really interested in seeing what kind of current I'm pulling. On my first (shortened) test run, I only hit 90A (I'm still running 8s) - but I had the sampling rate low (2/sec). I'll use 10/sec and see if I see any higher numbers.


Edit: my mistake - it was the other spindle that broke. Maybe it was just their time. Anyway, I'm still going to give the aluminum ones a try.

[brian015]

I pushed this pretty hard this afternoon on the soccer fields - lots of full throttle runs. Here's the current and voltage data (geared for 50mph, lvc set at 3.2V/cell, batteries - 8s Turnigy 40c 5000mAh):



Max power: 3443Watts (= 4.617 hp)
Max current: 124.4Amps

Temps at end of run:
ambient: 80F
esc: 132F (internal), 117F (external)
motor: 160F
batteries: one 4s pack 116F
other pack (actually 2x2s) 128F

[bryan]

Originally Posted by brian015

I finally got a chance to weigh this thing today, and with batteries it's 18.8lbs. Slightly more than I was expecting, but I was in the ballpark. My Muggy weighs 12lbs with batteries. The chassis, wheels/tires, and extra battery cells are the biggest differences between this and that (also motor and esc are a little heavier).

I landed a jump today a little on the nose and a front spindle broke near where the turnbuckle attaches - this definitely looks like a weak spot. Anyone have any luck with aluminum LST2 spindles?

i've got a muggy with 1/2" offset hex and alu. spindles and all good so far,And another with 1/2" offset Jconcept wheels standard hex also good so far. I think yours is a bit heavier than mine,and cooler.

Nevermind.

[brian015]

Originally Posted by bryan

i've got a muggy with 1/2" offset hex and alu. spindles and all good so far,And another with 1/2" offset Jconcept wheels standard hex also good so far. I think yours is a bit heavier than mine,and cooler.

I do think I'm pushing the limits on the LST parts with this much weight - but I have no real complaints other than these spindles. So I hope the aluminum upgrades are better - thanks for the input.

I haven't been driving my Muggy this summer - having too much fun with this one. I think it's going to feel small when I get it out again.


@Dj_Sparky - I saw your question about the motor and I guess you found it buried somewhere in this thread: Neu 1527 1.5y (825kv)

What size spur and pinion are you using?

[brian015]

Originally Posted by Dj_Sparky

What size spur and pinion are you using?

Here's the whole gearing set-up:

Differential Ratio: 4.090909090909091
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 48
Pinion Tooth Count: 20
Total Voltage: 29.6
Motor KV: 825
Tire Diameter (inches): 6.84
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0.012
Spur/Pinion Ratio: 2.4 : 1
Total Ratio: 9.81818 : 1
Tire Circumference (inches): 21.49 inches (545.81 mm)
Rollout: 2.19:1
Total Motor Speed: 24420 RPM
Vehicle Speed: 50.61 mph (81.3 km/h)
Effective KV Value: 825
KT constant: 1.64 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...

[brian015]

I tried this on 10s for the first time today. I again geared for 50mph (16t pinion) so that I could compare performance and temps to my 8s setup. Unfortunately my run was cut short by a broken pinion

I drove it hard again and used up 2.03Ah in just over 5 minutes. Comparing temps to my last logged run, it appears that both the esc and motor are running cooler.

Temps at end of (shortened) run:
ambient: 76F
esc: 105F external 118F internal
motor: 136F
batteries: 108F

The batteries I used for this were Turnigy 3600mAh 30c - and they didn't seem to have as much punch as the 40c batteries I normally use.

Here's the voltage and current plot:



Max current: 92.5A
Max power: 3147 W

What this tells me is that 10s is better, but I should stick with batteries with a higher current rating (although the 3600mAh 30c's should easily be capable of the currents I logged today). I'm looking at buying some new packs since my 40C 5000mAh packs are losing some capacity, and this shows me that I want to plan on running this on 10s in the future.

[lincpimp]

Just read the entire thread, very interesting and I like it!!!

As far as the spindles go, buy the al ones from New Era, best made for the lst2. I have them on mine and have no issues, run rpm arms and the stock lst2 rear hubs and stock lst2 c hubs. Stock hige pins as well.

Your idea to run long bolts thru the chassis/bulks and to a new top plate is a good one. Will give the shock tower something better to mount to as well.

I had a very similar idea to yours early in 09 and bough some al channel to make a buggy chassis using lst/muggy suspension and an 8ight center diff (have all the parts in a box ready to go). Mine was going to be shorter, to use the XTM XLB buggy body. Not sure on WB but it must have been around 16" or so.

I took my inspiration from Kershaw Designs and his mammouth based 1/6 scale buggy, he uses an Bergonzoni italian rc body, which is a bit bigger than the XLB body.

Had a look on his new site and it does not show the 1/6 scale buggy any more. Oh well, what you have done is better than his 1/5th scale anyways.

Since my buggy was going to be shorter length I had planned to use 40 series bowties on the back, and some truggy boties on the front to get the skinny tire look. Locking the center diff or going with very heavy fluid would help the front tires survive, as the skinnier tires are lighter and have less contact patch which will allow them to unload more than the rears (plus the weight transfer under acceleration) and wear faster. Alot of taping will be required, in my eyes.

I have a 10s car esc, and had planned to run esc brakes and reverse, on 10s lipo with a 1521 2y. I have a 1527 2y as well, but the kv is a bit low and figured the 1521 on 10s would be enough. I am aiming for 15lbs or less, as my tire choice is light, and I will run 10s 3200 30c lipos. I also have a 1717 castle motor and could run 6s, 5000 40c lipo. I think the 1521 on 10s would be better.

I am now rethinking the body, your exposed cage looks great, and I have made alot of tube bodies and chassis (I weld).

Look forward to seeing who your 10s setup works out.

[brian015]

Originally Posted by lincpimp

Just read the entire thread, very interesting and I like it!!!

Thank you.

Originally Posted by lincpimp

As far as the spindles go, buy the al ones from New Era, best made for the lst2. I have them on mine and have no issues, run rpm arms and the stock lst2 rear hubs and stock lst2 c hubs. Stock hige pins as well.

Good - I'll keep the New Era spindles in mind if the RDLogics don't work out.

Originally Posted by lincpimp

Your idea to run long bolts thru the chassis/bulks and to a new top plate is a good one. Will give the shock tower something better to mount to as well.

I think it's a good idea, too - I just have to get around to doing it!

Originally Posted by lincpimp

I am now rethinking the body, your exposed cage looks great, and I have made alot of tube bodies and chassis (I weld).

I've been looking at some of the sand rail conversions they're doing on the Baja's and really like the look of some of them - if only I could weld.

Baja Sandrail conversions

Originally Posted by lincpimp

Look forward to seeing who your 10s setup works out.

Yeah, I'm pretty convinced that 10s is the way to go with my 1527 1.5y (that gives it 30500 rpm). I want to squeeze in an extra 2s 5000mah 40c pack to run 10s with those packs (I'll have to stack a battery). To give me more battery options, I wish my chassis were about 1/2 inch wider. Oh well, I'll make it work.

[brian015]

I ran this today with 10s Turnigy 5000mAh 40c. I had to gear higher since my 16t pinion was broken. Gearing set-up:

Differential Ratio: 4.090909090909091
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 48
Pinion Tooth Count: 17
Total Voltage: 37
Motor KV: 825
Tire Diameter (inches): 6.84
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0.012
Spur/Pinion Ratio: 2.82 : 1
Total Ratio: 11.5508 : 1
Tire Circumference (inches): 21.49 inches (545.81 mm)
Rollout: 1.86:1
Total Motor Speed: 30525 RPM
Vehicle Speed: 53.78 mph (86.38 km/h)
Effective KV Value: 825
KT constant: 1.64 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...


Here's the voltage and current log:


Max current: 98.9Amps
Max power: 3619W

Temps at end of run:
ambient: 80F
esc: 122F (internal) 138F (external)
motor: 168F
batteries: 112-120F

So, I'd say my temps are about the same as 8s, considering I was geared slightly higher today. So much for my hope that 10s would bring my temps down. The only advantage might be battery temps were slightly lower - since I'm not pulling as much current as on 8s.

Then other thing I see is that my 5000mAh Turnigies seem to be giving out. I only used 3.97Ah today before hitting lvc.

So I need to look for some new packs - as much capacity as I can fit in this, I'll probably go with 10s, although it doesn't seem to matter.

[lincpimp]

Since you have a smooth can motor get some clip on heatsinks and some of that thermal paste. Should drop the temps at least 10f... Works for me, use them on everything I have that is not finned.

[V0RT3X]

I see you have RavenRC springs too, I'm rebuilding my Muggy shocks ATM and noticed since they are dual rate, did you pay attention that they are all orientated the same way?

The dual rate are 8.9 ppi at the top and 15 ppi at the bottom

At one side the coils are closer (softer) and on the other more apart (stiffer). Do you think it's important that the springs are orientated the same on all 4 corners? Or it doesn't matter?