22 replies to this topic

[Lipko]

Hi all!

The topic will be a bit strange. I'm thinking about making a Hummer/Humvee supercar with the Unimog wheels for about three months now. I will buy the Unimog in about three weeks, but I wanted to make a WIP thread about it, because I see more and more people "discovering" how awesome the Unimog wheels are for trucks like Hummer, and I'm pretty sure sooner or later someone else will make that Hummer.

So I just wanted a thread about this original-for-me idea and about what features and solutions I want to implement for a bit of evidence (at least for myself) that I'm not just getting on some band-wagon with the project and not only copying features.

The features and solutions are nothing really new, but may be interesting, and if someone else is overtaking me with them I would um..., you get the idea.

So the features:

• I want it RC, but not fully RC. Steering and going, but maybe not more.
  
• Independent wishbone suspension with the Unimog portal axle hubs. It's something that tickles my brain for months now, I wonder why I haven't seen this here on Eurobricks yet.
  
• Suspension has all the realistic stuff: Ackermann, chamber angle, caster angle and toe.
  
• adjustable suspension: stiffness and travel. Stiff and short travel for on-road, stiff and long travel for high speed off-road, soft and long travel for rock crawling
  
• All the obvious drivetrain features (transmission with R, hi/low selection, maybe torque distribution selector, independent differential lock on all three diffs).
  
• Winch. They are integral part of the Hummers' face. I want to include a clutch for pulling the hook out by hand.
  
• Winch and suspension setting is motorized (maybe with one motor and a gearbox), but not RC.
  
• I want to experiment with the chassis: A semi-realistic ladder chassis, and the two main beams are made of 2x2 beams connected with pins and 2x2, or 2x3 studded plates. I don't know how it will look or perform.
  
• Modular design. Already late with that.

That's it for now, I will soon try some things out. My biggest fear is that the Technic wishbone parts don't allow too much play for the ball-pin, so it won't be possible to build a fine working suspension without overly complex structure.

Edited by Lipko, 17 August 2012 - 03:50 PM.

[Sariel]

Lipko, on 17 August 2012 - 03:35 PM, said:

I wanted to make a WIP thread about it, because I see more and more people "discovering" how awesome the Unimog wheels are for trucks like Hummer, and I'm pretty sure sooner or later someone else will make that Hummer.

Someone already did.

Edited by Sariel, 17 August 2012 - 07:30 PM.

[AndyCW]

I mocked up something like this earlier this year and was left unimpressed with the dimensions that resulted.  The wishbones are 5 studs long, the center section is 5 studs wide, and the reduction hubs add significant wheel track width.  Overall with the unimog tires it looked out of proportion.  It looked too wide.  I thought about sacrificing the reduction hubs and going with the 8880 wheels, hubs, and unimog tires.  This would allow easier configuration of suspension geometry.  

Using non standard wishnbones may be the way to get the features desired within the scale desired.  Couple this with a non standard differential configuration that allows the center section to be narrower.

I remember someone using the unimog suspension pieces as lower control arms sometime in the past on here and this solution seemes quite well suited to Hummer suspension design, but it looses the reduction hub.

To maintain scale with the unimog tires the track width may need to resemble the width of the 9398 crawler.

Sariel, on 17 August 2012 - 07:29 PM, said:

Someone already did.

Wow

[Lipko]

Sariel, on 17 August 2012 - 07:29 PM, said:

Someone already did.

That's beautiful. I will look for other stuff on the net, there wasn't much Hummers in that scale 2-3 months ago.

[Lipko]

Some WIP photos about a sketch version:










more here

Implemented features so far:

• 4+R manual transmission
  
• Hi/LO selector
  
• central diff lock
  
• winch

Features that won't be implemented:

• first differential: real hummers don't have it either plus it will be hard enough to build the suspension
  
• adjustable suspension: not realistic, I don't think I can stuff that into the "small place"
  
• modular design. I'm not read for that yet

Next week probably I'll get the Crawler and the Unimog so the building speeds up at last.

Edited by Lipko, 11 October 2012 - 08:09 PM.

[piterx]

dude this rocks! way better than the yellow one!... cant wait to see updates :)

[Kronos]

I drove a Hummer for five years in the ARMY.  I recognised it right away.  Great job!  I look foward to the finished model.

[jorgeopesi]

Looks good!.

[Brix]

This looks great!

Please keep us posted as it progresses.

[Lipko]

A little progress with big compromises

• Front suspension: independent with the Portal axle hub. Ackermann (slightly imprecise), but no chamber angle, no caster angle, no toe  (I made a mistake in the previous post. There is a differential of course, but no diff-lock).
  
• Steering (working steering wheel)
  
• Chassis of the front half, some other tricky parts such as the power functions' attaching points (for two L motors + a servo motor)
  
• The nose is one stud longer because of the large offset of the wheel turning axle.

It looks quite good with the Crawler's wheels but the Unimog wheels will be the real thing.
Sorry for the bad photos and bad English, it's night here.

[Kronos]

I LOVE your HUMVEE!!!!!  This is awesome.  I can't wait for the finished project.  I hope instructions follow?  Maybe just really detailed pictures?  I HVE to have this on display!

Mike

[ciken]

can you take photo's of your suspension without wheels


greetz from belgium and an nice WIP humvee

[Lipko]

Thanks for the comments. I'm slowly getting to the point of giving the whole shit up. I'm giving up so much features the model eventually becomes like a Model Team vehicle but without the good looks. And I wanted a freaking Technic model.

Gave up so far:

• realistic suspension geometry
  
• front diff-lock (okay, that one wasn't important)
  
• Adjustable suspension
  
• Modularity (I wanted the model to be motorizable, but not motorized by default)
  
• Winch with clutch for manual pull-out

The rear differential lock is a real nightmare. Even Sariel's difflock is too wide. If I use a series of gears it will be too long. If I give that one up too, the project becomes meaningless.

[legomuppet9]

Lipko, on 23 October 2012 - 05:23 PM, said:

Thanks for the comments. I'm slowly getting to the point of giving the whole shit up. I'm giving up so much features the model eventually becomes like a Model Team vehicle but without the good looks. And I wanted a freaking Technic model.

Gave up so far:

• realistic suspension geometry
  
• front diff-lock (okay, that one wasn't important)
  
• Adjustable suspension
  
• Modularity (I wanted the model to be motorizable, but not motorized by default)
  
• Winch with clutch for manual pull-out

The rear differential lock is a real nightmare. Even Sariel's difflock is too wide. If I use a series of gears it will be too long. If I give that one up too, the project becomes meaningless.

Don't give up , the project looks to be coming along nicely from the previous photos and it looks just like the real thing

[AndyCW]

I originally thought that the dimensions would not add up and it would look out of proportion. I want you to prove me wrong.  The updates over the past week have been wondeful.  Please continue.  I drove a Hummer for many miles in Iraq and have "fond" memories of those vehicles.

The differentials could be turned 90 degrees and this would free up space for those differential locks you were hoping for.  It may also enabel a narrowing of the track width by two studs.

[Aussie BJ]

Great MOC really like the scale. I took these pictures last weekend on the Gold Coast (Australia) and thought you might like. Would give you plenty of room!

[rm8]

Lipko, on 23 October 2012 - 05:23 PM, said:

Thanks for the comments. I'm slowly getting to the point of giving the whole shit up. I'm giving up so much features the model eventually becomes like a Model Team vehicle but without the good looks. And I wanted a freaking Technic model.

Gave up so far:

• realistic suspension geometry
  
• front diff-lock (okay, that one wasn't important)
  
• Adjustable suspension
  
• Modularity (I wanted the model to be motorizable, but not motorized by default)
  
• Winch with clutch for manual pull-out

The rear differential lock is a real nightmare. Even Sariel's difflock is too wide. If I use a series of gears it will be too long. If I give that one up too, the project becomes meaningless.

Looks like 100% HUMVEE.
Wish you not to give up and go forward!

My Toyota uses rear differnetial lock, with differential of new type, but suspension is live axle, not independent.

Today I'll try to photo my rear axle with difflock and post it at Toyota topic.

[Lipko]

Yeah, I should build instead of pussying around. I looked for differential designs over the web, I saw your Toyota rm8 (it's an impressive model!), but neither of them fits my needs. I don't want to give up the independent suspension, and I can't increase sizes any more (one or two studs is okay in length but I can't increase the width). And I don't want to give up the difflock, it would be just lame, as it's pretty much a basic feature of any off-roadish vehicle.

The one thing that I could give up is the portal axle. Which I obviously won't (since it's so characteristic to Humvees). I could use a custom one instead of the Unimog's/crawler's, but I also want the more stiff base for the wheel instead of a single axle (I often see the slightly tilted-invard and weak wheels of otherwise great and iconic models).

I want to use as few gears as possible, because I'm a bit worried about backlash. Too much backlash will significantly increase (at least to my understanding) the load of the drive train, since the motor can speed up to full speed without much load until the backlash is "used up" then BAM, full load at full speed.

The other problem is that I use the new type of differential at the front (due to the small place), so I can't just use the old type at the rear because then can't simply lock the central diff due to the different gear ratios. The only other gear with the same tooth count is the mini turntable. Or I could use a series of gears somehow, but sigh.....

So, it's not an easy one. And it's pretty annoying that a simple looking basic feature takes so much effort and space.

[Kronos]

I applaud your effort.  Hearing the difficulties you are having makes me respect MOC builders even more.  The creations out there are beyond my ability.  (At least for now )  I didn't mean to sound demanding, and I will wait patiently for updates.  Thanks for the great work.

Mike

[Lipko]

Update:

Project cancelled.

The project was over my head and the whole building process was a huge mess, so I disassembled it. I will build it again, but I'll have a few (at least one) warm up project before that. See other thread.

[chorlton]

Lipko, on 13 December 2012 - 08:14 PM, said:

Update:

Project cancelled.

The project was over my head and the whole building process was a huge mess, so I disassembled it. I will build it again, but I'll have a few (at least one) warm up project before that. See other thread.

Sorry to hear it's cancelled but your open explanations is much appreciated (and encouraging for us amateurs).

[jorgeopesi]

Lipko, on 13 December 2012 - 08:14 PM, said:

Update:

Project cancelled.

The project was over my head and the whole building process was a huge mess, so I disassembled it. I will build it again, but I'll have a few (at least one) warm up project before that. See other thread.

I feel the same all the time, the second or third time you build the same thing, without realizing, you overcome things that were difficult before.

[AndyCW]

The portal hub is not a mandatory thing for Hummers.  8880 wheels and hubs + unimog tires could suffice for the below  HMMWV version.
http://www.oshkoshde...gsup-suspension

Hope to see more.

v/r
Andy