Solid Axle Pro4 SCT

[Culetto]

Originally Posted by desertmaxx

cool..... the roll cage is..... interesting.... i bet it is light.....

Not as light as i would like but its getting there. My rango ready-to-race is 5.5 lbs. This thing will be about 7 lbs with the current design. I drew up a new chassis plate today to take some weight out and adjust the balance and once my body mounts come in (tomorrow hopefully) ill redraw the forward cage panels to take a little more weight out. If i can get it to 6.5 lbs ready-to-race ill be happy.

[Big Mike]

I have to admit, my initial reaction was " Noooooooooooooooo!!!!!"

I most certainly did not want to witness the demise of an MBX6. But something drew me on...

Now that I've read through the whole thing, my opinion is that the sacrifice was indeed worthy. What a unique and well executed build. The way you've adjusted your methods and approaches (especially the trailing arms) to better fit the tools and materials at your disposal is very cool stuff. Well done.

I'm jealous - you have fun toys to play with in your shop.

I'm lookin' forward to video of this beast in action...

[Culetto]

Originally Posted by Big Mike

I have to admit, my initial reaction was " Noooooooooooooooo!!!!!"

I most certainly did not want to witness the demise of an MBX6. But something drew me on...

Now that I've read through the whole thing, my opinion is that the sacrifice was indeed worthy. What a unique and well executed build. The way you've adjusted your methods and approaches (especially the trailing arms) to better fit the tools and materials at your disposal is very cool stuff. Well done.

I'm jealous - you have fun toys to play with in your shop.

I'm lookin' forward to video of this beast in action...

LOL, to be honest i thought the choice of buggy would cause an uproar but i havent gotten much flak about it. Thanks for the feedback. Only a month to go before the Cabin Fever race and hopefully this thing will get some track time.

[billzkustomz]

how is the handling with the solid axle?

[Culetto]

Originally Posted by billzkustomz

how is the handling with the solid axle?

Dont really know yet. In theory the solid axle will be more a disadvantage because the reaction of the rear wheels is now tied together AND you cant dial in camber gain. But it should have an advantage in the actual race by destracting other drivers with its coolness and that should help me win

[Meatwad]

Originally Posted by Culetto

Dont really know yet. In theory the solid axle will be more a disadvantage because the reaction of the rear wheels is now tied together AND you cant dial in camber gain. But it should have an advantage in the actual race by destracting other drivers with its coolness and that should help me win

Lol though you do have toe options too.

[Culetto]

Originally Posted by Meatwad

Lol though you do have toe options too.

Yup, toe and camber.

[Meatwad]

Originally Posted by Culetto

Yup, toe and camber.

Between that and coolness factor, that's enough ammo

Awesome rig man. Wonder when manufacturers will hop on board and offer one. The obvious guess is axial first with having solid axles already. Time will tell

[billzkustomz]

Originally Posted by Culetto

Dont really know yet. In theory the solid axle will be more a disadvantage because the reaction of the rear wheels is now tied together AND you cant dial in camber gain. But it should have an advantage in the actual race by destracting other drivers with its coolness and that should help me win

oo thats cool solid axle..passed sonofa..

[Inclodneato]

this truck is amazing, so cool

[Culetto]

Crap, ok lets try this again (after typing it all out once already on rcsc just to find out its not letting anyone post atm)

So its been a bit since i got to update this. Even with being out of town i did manage to get a lot done. The body mounts came in and got installed, the fore chassis uppers got updated, the chassis plate got updated, the battery pack layout is finalized, and there is a shakedown set of electronics installed. I actually ran it in the shop tonight just to check the install, its gonna be pretty quick.


DSC_0217 by phukyr, on Flickr


Front and rear body posts are from the RC8T.

DSC_0218 by phukyr, on Flickr

Decided to keep the saddle config but for balance sakes i moved the esc up between the chassis plates and split the battery to each side on the chassis.

DSC_0219 by phukyr, on Flickr


Rear body posts, also from AE, are on delrin spars. These may or may not change. They work well but i may try to design something that allows them to move and adjust more since so many sct bodies are different in this area, especially as far as angles and depth goes.

DSC_0220 by phukyr, on Flickr

Pulled the Tekin pro4 and put in a castle 4pole and mamba monster setup. The main reason for this is i need the pro4/rx8 for my durango for the race next weekend. As much as i want to run this in the race i just cant justify the cost of tires and i cant run 1/8 tires on sct for this race. So the rango goes, hopefully this will get some practice.

DSC_0221 by phukyr, on Flickr

The esc plate is angled down and forward. This was mainly just to use some holes i already had in the design but it also will give it good airflow (not that the MMM needs airflow running this motor on 2s, i dount ill get the fan to even come on if i put a 20t pinion on it)

DSC_0222 by phukyr, on Flickr

Finally got the front end figured out. I had it done once, and then realized that to change the fron diff fluid or lower arms i would have to take the entire chassis apart. Now its a simple 4 screws to pull the skid off. The lower chassis was milled out 1/8 inch just behind the front diff screws so this skid would sit flush. Its then heated up with a heat gun and folded up to meet the chassis where its screwed into the front uprights.

DSC_0223 by phukyr, on Flickr


DSC_0224 by phukyr, on Flickr


SO now, with the body mounted and plugged in ready to rock, its at 7lbs 5oz. Not bad really, its lighter than it was. It will also shed a little more with a more race tire (these are pretty heavy) and a clean body (the test body STILL has dried mud on it, lol. You may not be able to tell in these pics but the main vertical plates are lightened. The holes that reminded everyone of a dinosaur skull were all enlarged about 3mm to take some weight out overall and lower the CG. It worked out pretty well. Aside from dropping the front bumper on it, its done and ready to test.

DSC_0225 by phukyr, on Flickr

So heres my grief, i cant IMAGINE how someone would do this type of thing for a living. It would be a blast, dont get me wrong, but how would you ever call something done. From the shop into the house i thought of 4 more things i want to change on it and i havent even had it on the track yet. Oh well, test first, change later i guess.

[Zeus.:God]

Wow, this is how all short course trucks should have been from the start. Excellent work.

[Bart bender]

Originally Posted by Zeus.:God

Wow, this is how all short course trucks should have been from the start. Excellent work.

Fo sho!!!

VI-DE-O!

[Culetto]

OK WTF ever, i give up trying to embed the video, LOL.

Shakedown run with pro4 solid axle truck.

Its funny but it cant get up to full speed on the snow. Above about 5/8 throttle it just spins the wheels and wont accelerate. Maybe cause thats when max boost comes on . Anyhow it was fun to see it go. You can see where the rear suspension is still too stiff. Also it looks like i may have to fiddle with the weight again. I didnt want to add any more but if i cant get the tail settled down with the oil/spring i may have too. Still another week before i head down to the Cabin Fever race. Depending on the turnout i want to get it on the track for some practice.

[Bart bender]

Sounds like you've got the fix for the issues figured out. The track will be the true test

[Culetto]

Originally Posted by Bart bender

Sounds like you've got the fix for the issues figured out. The track will be the true test

Ive got it figured out, with bonus. I need to figure out the patent process for my new pistons.

[Culetto]

Took a bunch of poser shots while i had it outside yesterday also. Nothing special but it looks good in the snow, lol.


DSC_0267 by phukyr, on Flickr


DSC_0266 by phukyr, on Flickr


DSC_0264 by phukyr, on Flickr


DSC_0263 by phukyr, on Flickr


DSC_0262 by phukyr, on Flickr


DSC_0261 by phukyr, on Flickr


DSC_0260 by phukyr, on Flickr


DSC_0259 by phukyr, on Flickr


DSC_0257 by phukyr, on Flickr


DSC_0256 by phukyr, on Flickr


DSC_0254 by phukyr, on Flickr

This is where the droop is set atm. Figured it would look better sorta scale since all the shots ive seen of pro4 the rear does drop out a little more than the front.

DSC_0270 by phukyr, on Flickr

Finally got the workbench cleaned up. Time to race!!!

DSC_0271 by phukyr, on Flickr

[ejohnson]

look great, whats the advantages of running the solid axle?

[Culetto]

Originally Posted by ejohnson

look great, whats the advantages of running the solid axle?

I get a bonus to lateral wow factor and a big increase in jumping cool points.


Seriously there isnt really a benefit in performance except maybe more sideways grip on the rear end on a loamy track (ever notice how often full scale pro4 guys roll in the turns from the rear end biting and tossing them). Most full scale guys will tell you the solid rear axle has some inherent disadvantages over IRS in bump handling since the wheels are directly connected and any force acting on one side will effect the other side. Some people have told me that these effects are increased when you get into small scale trucks at much higher 'scale' speeds. So in theory it will be worse. I have my own theory that i can still make it very competetive while looking much more scale on the track.

[Culetto]

So back from the big Cabin Fever race. Was a LOT of fun even tho the truck broke.


So i had forgotten that one of my rear suspension uprights had been a hot cut (melted the delrin a bit more than it should have). Originally i used it anyway to check for fitment and then ..... totally forgot about it, LOL. So when i snagged the rear axle on the big launch into a table top it snapped the screw right out of it and was done for the weekend. Overall it felt better than i expected on the track. The rear had a rediculous amount of grip which im still trying to figure out why. One the big sweeper i had to really let off the loud pedal before the turn and get back on it hard at the apex to keep it from rolling.


Short Video of a couple laps is HERE. I grabbed a different body before i left since the losi i had been testing was cracking across the windshield. The one on there is the original JConcepts raptor, not the v2, that i used to run on my rango. It fit just as well, if not better, than the losi.



NOw that ive had it on the track and seen what broke and what worked well the upper plates will be getting a full redesign including double sheer rear link mounts and the front of the cage will not stop at the front shock tower. Wont be as 'scale' but will take some weight out of the front end and move the cg a little further back. Im already excited to get it back out onto a track.