MAC FAB Bomber build, TAKE 2

[JatoTheRipper]

That looks bad ass! I love the hood. And the wheels look perfect on there.

[MAC FAB]

Originally Posted by TheLetterJ

Have you looked at the Traxxas Summit diffs? They're definitely larger than the TRX4, but they're functionally the same (selectable locker) and come in an IFS/IRS package.

Been there done that with the car that this original thread is about, Summit locking diffs and all. Just thinking about doing another "out of the norm" type of build for the cage that arrived today. I haven't pinned down if I put an unusual spin on the solid axle format, go full indy again, but with all A arms or make it a 2wd speedster. I have most parts needed for a 2wd right now, but that defeats the purpose of the KOH/crawler intent. But it would be cool, I can see that in my head already. Time will tell what it will be.



Thanks Jato for the kind words.

[MAC FAB]

Can someone give me a couple measurements? Looking at the bare chassis and not having used a skid yet, I'm not sure where/how the skid mounts to the cage, but I am looking at 3 holes per side. My question is where do the lower links mount fall in relation to any of those 3 holes (pick one and measure back to the link bolt hole) and how long is it with standard length rear links when connected to the rear axle, meaning length from the skid location of the link to the centerline of the rear axle? I am trying to locate the stock location for the axle without actually having one. This new rig will hopefully be a light weight build, opposite the original one that is heavy but low CG. I'm leaning towards building a speedster this time around.

[MAC FAB]

After some long contemplation, I've decided to do another 4wd, all independent build, perhaps using a rear trailing arm (similar yet different than the Take 2 Bomber) and unequal length A-arms up front. If the front theory/design will work like it does in my head, it will probably get the same treatment out back as well for some 4 wheel steering. This may not be the wisest front end application, let alone the rear, and no one has done that in RC yet that I've seen so why not try, right? 13"-14" wide, 14" wheelbase, or there abouts. Does this spark anyone's curiousity?

[MasteroFlego]

Originally Posted by MAC FAB

and unequal length A-arms up front.

What do you mean by unequal?

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[MAC FAB]

In a plan view, consider the passenger side front of the chassis. Now take and place a number "7" where the horizontal member of the number goes to the front bumper, and the bottom of it going to the vertical tube below the A pillar where the forward screws hold on the body panel there. See the pic below, you can barely see the upper rearward mount. That make sense? I want to do this, and make it 4wd......

IM001524 by MAC FAB, on Flickr

EDIT: I found a better pic.

20180404_203239 by MAC FAB, on Flickr

[MasteroFlego]

I'm still confused lol. That's a sweet buggy though, it'd be cool to see a mini version.

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[MAC FAB]

Originally Posted by MasteroFlego

I'm still confused lol. That's a sweet buggy though, it'd be cool to see a mini version.

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That buggy is a blast, I've been to baja pre-running and pit support with the guy who owns it many times. It took 3rd at the NORRA 1000 (similar to a rally in timing, but racing in baja) last year Sportsman class.

Anyhow, the explanation:

The portion/side of the A arm that bolts to the center of the car is considerably shorter than the other portion/side that goes into the side of the chassis near the driver's feet, which is dog leg bent for steering clearance, therefore unequal length. This design is not as strong as traditionsl boxed A arms, but works well. Sand cars ran this setup because they were lighter than a traditional boxed version. As sand cars evolved, many now are simply glamourized class 1 buggies with mega HP motors. My reasoning for going this route is the axle is out of harms way as far as hitting suspension parts, and I can run the tie rods in front if necessary. Another plus is I can either make (larger mounting and smaller bearings for more angle) or use nearly anyone's knuckles to simplify steering, I just need custom length axles that have joints on each end and some plunge available. MIP X duties would probably be the go to part. I have 1/4" X .065" tube to build them out of, and can tap the tube to thread in some metal rod ends. The downer is it takes 12 heims to build the front end, using 8 for mounting the arms. Cool thing is shocks can be mounted to the top arm OR lower and be leveraged out to keep them short and out of the way.

[MAC FAB]

Prototype time. Are E Revo rod ends 4mm thru and thru?

20190418_101419 by MAC FAB, on Flickr

20190418_101514 by MAC FAB, on Flickr

[TheLetterJ]

Revo rod ends are 3mm through the ball, 4mm through the plastic shank.

[durok]

That top-down view with the spare mounted up makes the rig look like a tadpole..

Interested to see what you come up with this time around!

[MAC FAB]

Thanks. I am hoping the E Revo ends will be up to the task, metal ones are $8 each. Upper and lower arms are mig welded to expedite fab, and they are amazingly strong. Getting the rear heims connected to the chassis may be my challenge, being I am trying to keep them (arms) as long as possible to minimize wheelbase change. Hopefully I'll find time this w/e to come up with a mounting solution. Battery has to go mid board this time.

[MAC FAB]

I hate waiting for parts..... Progress will happen next week!

[MAC FAB]

Well my spindles will be great, for a 2wd. Would probably have to be a dog bone arrangement, but I need some plunge. Silver lining is the beam car can easily happen now, a go faster baja bug build. Anyone got some pics of what Yeti/Exo uprights and spindles look like? JConcept Sl4sh uprights may be the solution. Back to square one, again.

[Brian5582]

No input on ESCs but the car is oh so hawt!!!

Edit... apparently I was replying to an old post lol idiot

[MAC FAB]

Scratch this front end on a Bomber, I'm not into short travel builds. That is what is needed for this to work. So its going on a UDR sized scratch build buggy instead. Matching rear steer parts will complete the VW style beam 5 ultd. bug build that has been cluttering the bench. Life goes on, just in different directions.....

20190430_145907 by MAC FAB, on Flickr

20190430_150152 by MAC FAB, on Flickr

No room for drive shafts, bummer. This arm setup easily cycles 5" of travel with 45 degrees either way in steering.

[MAC FAB]

So I haven't driven my Bomber since about March, so why not drive today, right? Got about 200 feet in distance and lost the set screw on the pinion. Thankfully I was close to the house. What is the solution for that, loctite???

[durok]

Originally Posted by MAC FAB

So I haven't driven my Bomber since about March, so why not drive today, right? Got about 200 feet in distance and lost the set screw on the pinion. Thankfully I was close to the house. What is the solution for that, loctite???

Loctite, most definitely!

[MAC FAB]

Originally Posted by durok

Loctite, most definitely!

Thanks durok. I figured that was going to be the case, but didn't want to do it and then not be able to get it off by stripping the set screw. That would be a major car dismantling to cut the gear off the shaft if it went bad.

On a side note, what is anyone's take on an 1/8th scale Goolrc 2650 kv and perhaps the 120 amp esc that comes in their 1/8 scale kit? Looking for cheap stuff with moderate/decent performance. The reason being that electronics are short lived with all the iron/fine silt in the dirt where I run.

Finally, any Bomber guys in the Riverside, Mo Val, Hemet, San Jac, Temecula (IE) area?

[Strgazr27]

such a sick build! Love the work!