[MOC] Sand Jeep

[Lejeansur]

Hey !

i made this during holidays... It's pretty fast with 2PF L for propulsion and 1 servo for steering :)

i also made this short video, can you tell me some tips in order to improve it ?

My next project will be a 8X4 or 6X4 truck 

[Leonardo da Bricki]

It is not bad, but it would definitely benefit from increased ground clearance. Also, Jeeps tend to have live axles, as opposed to independent suspension, but yours appears to work well. One other thing, maybe try using some slightly bigger wheels, as the ones you have used are a bit small for the size of the Jeep.

[Jurss]

Looks nice.

From side ground clearance somehow looks OK, but overall it seems too low.

[Qukie]

Looks good and seems to drive really well despite the low ground clearance which I like.

Do a 6x4 truck next.

[mocbuild101]

Looks nice, I think the wheels might be too small, although the next size up (in balloon tires) is very big...

A way to make them seem bigger is to make it more like a buggy than a jeep - and the independent suspension would be more realistic too

[Lejeansur]

On 12/6/2017 at 7:57 PM, Leonardo da Bricki said:

It is not bad, but it would definitely benefit from increased ground clearance. Also, Jeeps tend to have live axles, as opposed to independent suspension, but yours appears to work well. One other thing, maybe try using some slightly bigger wheels, as the ones you have used are a bit small for the size of the Jeep.

yeah but i wanted to try a jeep without live axles.... but is it a jeep anyway ? ;)

[camellia]

It's cool!

Do you use two motor to drive left and right wheels separately?

I didn't see the differential in the rear.

When turning, the left wheel and right wheel have diffferent speed, if it doesn't have the differential, the left wheel and right wheel will have different force effect. It is bad for wheels and motors.

If you have already design the differential, it is good.

I make a lesson about differential by myself. 

 

[Void_S]

12 hours ago, camellia said:

When turning, the left wheel and right wheel have diffferent speed, if it doesn't have the differential, the left wheel and right wheel will have different force effect. It is bad for wheels and motors.

It's a really bad solution in case of a surface that provides a constant good grip (friction), like asphalt road for a typical road car, but in case of a sandy or rocky surface now it's advantage to have a solid (locked diff) or semi-solid axle, and especially in case of only RWD it's nearly vital

Don't get me wrong, but I believe that the most of members can explain  the all pros and cons of the differentials and provide a ton of their models, so the lesion is nearly pointless here...

By the way I'd like to add that I love how this jeep moves over the stones, smooth and easy like a viper... Amazing MOC, @Lejeansur 

Edited June 17, 2017 by Void_S

[andythenorth]

On 2017-6-17 at 11:03 AM, camellia said:

When turning, the left wheel and right wheel have diffferent speed, if it doesn't have the differential, the left wheel and right wheel will have different force effect. It is bad for wheels and motors.

Why?

[mocbuild101]

24 minutes ago, andythenorth said:

On ‎17‎/‎06‎/‎2017 at 8:03 PM, camellia said:

When turning, the left wheel and right wheel have diffferent speed, if it doesn't have the differential, the left wheel and right wheel will have different force effect. It is bad for wheels and motors.

Why?

Wheels - the wheels will try to turn at the same speed (but they can't), which causes them to slip - and wear down the rubber slightly.

Motors - forcibly slowing or speeding up motors will cause uneven wear to the gears inside of them.

[andythenorth]

2 hours ago, mocbuild101 said:

Motors - forcibly slowing or speeding up motors will cause uneven wear to the gears inside of them.

No it won't  Motors forcibly slow down or speed up in response to load all the time.  When cornering, the variable speed of the inner and outer wheels just varies the load on each motor.

Lego motors are just cans in a plastic case, with some gears.  They're not precision industrial motors with constant-speed controls. There's nothing there that's going to be significantly damaged in the short term by this setup.

One motor might probably draw a few more mA than the other one, and it will run a bit warmer, so if you left the vehicle going round in circles for days, one motor might have a shorter lifespan than the other, but nothing to write home about    If you really stalled one, the thermal protection would kick in.  I'd love to see Philo comment on the topic, but eh.

If the motors were constant-speed each with their own motor driver, then yes, this would be a valid concern, and the vehicle would try and run in a straight line, like a mechanically coupled axle with no diff.  But I've run one-motor-per-wheel, quite a lot.  

If it was a problem, this vehicle with one L motor per-wheel wouldn't turn on a dime Especially given it has no weight over the steer axle, so the steer wheels are prone to floating.   But it works fine see the video 

Sorry for hijacking this thread - I sometimes see a bit of angst in Eurobricks about using multiple motors, it's mostly no drama.  

Edited June 18, 2017 by andythenorth

[Lejeansur]

On 17/6/2017 at 0:03 PM, camellia said:

It's cool!

Do you use two motor to drive left and right wheels separately?

I didn't see the differential in the rear.

When turning, the left wheel and right wheel have diffferent speed, if it doesn't have the differential, the left wheel and right wheel will have different force effect. It is bad for wheels and motors.

If you have already design the differential, it is good.

I make a lesson about differential by myself. 

 

 

21 hours ago, Void_S said:

It's a really bad solution in case of a surface that provides a constant good grip (friction), like asphalt road for a typical road car, but in case of a sandy or rocky surface now it's advantage to have a solid (locked diff) or semi-solid axle, and especially in case of only RWD it's nearly vital

Don't get me wrong, but I believe that the most of members can explain  the all pros and cons of the differentials and provide a ton of their models, so the lesion is nearly pointless here...

By the way I'd like to add that I love how this jeep moves over the stones, smooth and easy like a viper... Amazing MOC, @Lejeansur 

yes i know the benefit of a differential but i wanted to try this system 

it's interesting to create new propulsion system, even if the tire are a little bit damaged :)

 

 

[camellia]

Hi!

I agree with andythenorth. A motor has the rated power and the real power. When running, its power and speed is affected by loads.

Just as I said in the beginning of my reply "Do you use two motor to drive left and right wheels separately"

A differential is used when only one motor drives left and right wheels.

As Lejeansur used two motor for left and right wheels separately, a differential is not need.

All of you are experts.

I'm happy to discuss with you!

10 minutes ago, Lejeansur said:

 

yes i know the benefit of a differential but i wanted to try this system 

it's interesting to create new propulsion system, even if the tire are a little bit damaged :)

 

 

 

4 hours ago, andythenorth said:

No it won't  Motors forcibly slow down or speed up in response to load all the time.  When cornering, the variable speed of the inner and outer wheels just varies the load on each motor.

Lego motors are just cans in a plastic case, with some gears.  They're not precision industrial motors with constant-speed controls. There's nothing there that's going to be significantly damaged in the short term by this setup.

One motor might probably draw a few more mA than the other one, and it will run a bit warmer, so if you left the vehicle going round in circles for days, one motor might have a shorter lifespan than the other, but nothing to write home about    If you really stalled one, the thermal protection would kick in.  I'd love to see Philo comment on the topic, but eh.

If the motors were constant-speed each with their own motor driver, then yes, this would be a valid concern, and the vehicle would try and run in a straight line, like a mechanically coupled axle with no diff.  But I've run one-motor-per-wheel, quite a lot.  

If it was a problem, this vehicle with one L motor per-wheel wouldn't turn on a dime Especially given it has no weight over the steer axle, so the steer wheels are prone to floating.   But it works fine see the video 

Sorry for hijacking this thread - I sometimes see a bit of angst in Eurobricks about using multiple motors, it's mostly no drama.  

 

5 hours ago, mocbuild101 said:

Wheels - the wheels will try to turn at the same speed (but they can't), which causes them to slip - and wear down the rubber slightly.

Motors - forcibly slowing or speeding up motors will cause uneven wear to the gears inside of them.

 

[arnold45]

Good Jeep build man. The stance and ground clearance looks good to me.

[Lejeansur]

thanks for the advices ;)