1/6 Losi Hummer (CC1717) Build

[brian015]

I took this out for its first shake-down run and everything looked good. I ran it for 5 or so minutes - lots of power from the esc/motor combo on 6s.


Here is the set-up I'm running:

Castle xo-1 1717 motor (1650kv)
EZrun 150a Pro esc
2x6s Gens Ace 4000mAh 25c in parallel
Hostile MX fronts all around
Muggy gearing (45/11)
50t spur/14t pinion

Here is the top speed estimator:

Differential Ratio: 4.090909090909091
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 50
Pinion Tooth Count: 14
Total Voltage: 22.20
Motor KV: 1650
Tire Diameter (inches): 6.5
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 3.57 : 1
Total Ratio: 14.61039 : 1
Tire Circumference (inches): 20.42 inches (518.68 mm)
Rollout: 1.40:1
Total Motor Speed: 36630 RPM
Vehicle Speed: 48.48 mph (77.88 km/h)
Effective KV Value: 1650
KT constant: 0.82 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...

I hope to get it out for a longer run this weekend and check temps with this gearing.

[_paralyzed_]

It must have felt so good to finally pull the trigger on this bad boy!

It looks awesome, congratulations on a great build.

Get that thing dirty

[brian015]

Originally Posted by _paralyzed_

It must have felt so good to finally pull the trigger on this bad boy!

Yes it did! Thanks Harold.

[el tomaso]

Any videos

The car came out great, I hope it drives as good as it looks

Thomas G

[brian015]

Another test run - I need to tune the suspension a bit - I'll start with some thicker shock oil to try to make it less "bouncy" with the stiff 5ive-T springs. I probably have a bit too much toe-in as well. But here's a quick video so you can see how it looks:



(and thanks to Daniel, my 7-year old, for taking the video)

[Overdriven]

You got a good camera man there, especially for his age!

I was reading back through the thread and I noticed the lexan you put on top of the shock piston for the variable damping. I like the idea and will experiment with it on my build. It probably helped alot when using LST springs on a fairly heavy rig as it adds compression damping without effecting rebound much. But I wonder if now the springs are strong enough to not require that added compression damping and placing them under the piston to add rebound damping. I'm sure you probably had this thought and obviously more testing would be required before coming to any definite conclusions.

Just something in head. Thanks for the update, love the build and I'm really curious as to how the springs/damping part works out.

[brainanator]

Great camera work from the little one!
And I guess the truck isn't half bad either...

[brian015]

Thanks for the kind words - and I'll pass them along to Daniel.

Originally Posted by Overdriven

I was reading back through the thread and I noticed the lexan you put on top of the shock piston for the variable damping. I like the idea and will experiment with it on my build. It probably helped alot when using LST springs on a fairly heavy rig as it adds compression damping without effecting rebound much. But I wonder if now the springs are strong enough to not require that added compression damping and placing them under the piston to add rebound damping.

That's exactly why I modified the piston - because even the RC-raven springs were not strong enough for these larger trucks. So, I may just get rid of the lexan pieces if I'm not happy with the suspension (I hadn't considered your idea of putting them underneath to add rebound damping - but I'll keep it in mind) . I put thicker oil in the shocks yesterday and like the way it feels just sitting here pushing on it - but I'll have to get it out again and test it.

[brian015]

I guess it's been a while since I've done anything with this truck (busy couple of months - I'm starting a new job, will soon be moving, etc.).

Anyway, I put thicker shock oil (30wt) in the shocks and it handles much better. I might even go thicker.

The electric brakes on the HW esc are very strong - I did a front flip when I slammed the brakes on today (I think I have them programmed to 50%, but I'll have to check). But this truck is running pretty well.

[Bmr4life]

Originally Posted by brian015

I guess it's been a while since I've done anything with this truck (busy couple of months - I'm starting a new job, will soon be moving, etc.).

Anyway, I put thicker shock oil (30wt) in the shocks and it handles much better. I might even go thicker.

The electric brakes on the HW esc are very strong - I did a front flip when I slammed the brakes on today (I think I have them programmed to 50%, but I'll have to check). But this truck is running pretty well.

I think its more so the 1717 having an immense amount of braking power.

[Bondonutz]

Haven't checked back on this thread in a loong time, gotta say it finished very nicely !
Great work Brian.

[brian015]

Originally Posted by Bmr4life

I think its more so the 1717 having an immense amount of braking power.

That might be the reason - All I know is that these brakes are much stronger than the mechanical brakes I was using on my other large-scale build.

Originally Posted by Bondonutz

Haven't checked back on this thread in a loong time, gotta say it finished very nicely !
Great work Brian.

Thanks Bondo - I must admit I haven't driven this too much - so I haven't had anything to add in a while.

i gotta agree with bondo there brian....nice work on the fabbed parts.
a great looking truck
chris

[brian015]

Thanks Chris - just wish I had more time to drive/tune this thing.

I do think the 1717 is a great motor for something this size - I still can't believe they released the HPI 5SC Flux without it!

[Bondonutz]

I hope Castle doesn't get beat up on 2200kv and/or ESC issues from HPI under motoring that thing ?

BTW Brian, Have you seen all the fab work I've done on my build ? I think you'd appreciate it since you like to make from scratch like myself.