AndyCW

RC Flat Bed Pickup

25 posts in this topic

The combination of the newer receivers and the RC buggy motors is really outstanding. This thing produces more torque than my older setup with 15:1 gearing on the old receivers. The old setup would stall with PP tires on the smallest obstacles and this new setup with much less gearing will not stall the motors unless something obscene happens. Managed to mangle an eight tooth gear inside of the portal hub during a particular nasty hill climb that is not included in the video. I think the new axles from the 9398 will help the next set of eight tooth gears survive longer. The truck kind of reminds me of the arctic glacier trucks and with the unimog tires it still looks good.

The steering servo was easily overwhelmed by the terrain, PP tires, and steering geometry. I tried the LPE power unimog front geometry and it performed much better, but the CV joints would pop apart at the hub under any stress. Still looking on how to make the better geometry trial truck strong. The body work is getting progressively better on each of my projects, but still remains my weakest area.

The old setup is

questions, concerns, comments

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Looks like a very capable truck, and the PP wheels look great. What are you using to power the motors?

tim

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Pics as requested

You can see the mangled eight tooth gear on the rear axle.

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Edited by AndyCW

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WOW, this thing spins the PP tyres like they weigh nothing and flys over obsticles. At first I wondered if the video was sped up. The new recievers and servo motor is performing great. TLG should base the differencial on a 36t double bevel gear (with the middle scooped out so it's 1/2M wide) instead of a 28t single bevel.

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Outstanding! Is very nice that the new receivers can be combined with rc motors!!

I like the chasis too is really cool! :classic:

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I was somewhat worried that people would think that the video was sped up. I sped up the part on the turn table, but left everything else 1X speed. I just tried it with 12/20 gearing in the hubs for an overall of 5:1. I combined this with the unimog tires and it will stall the motors on medium obstacles. I want to try 3:1 overal and get a measure of capability. I am also looking at using a two speed transmission with 8.3:1 being low and 3:1 being high. 5:1 axles combined with the two speed transmission from Sariel. Packaging it in the current size chasis is going to be a challenge. It will end up being a King of the Hammers inspired vehicle. (both crawling and high speed) I need to get my hands on one of the proportional controllers to alleviate driveline jerk.

Edited by AndyCW

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I really like those U joints, but the wouldn't work with what I am doing right now. A couple of updates to the new version. Sariel's two speed gearbox is six studs across and needs one stud of travel to shift gears. This works really well with two buggy motors butted together because the outputs are seven studs apart. It fits really well in the chasis. I just needed to shorten the driveshafts.

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Low Gear 8.3:1

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High Gear 3:1

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For additional info on chasis construction

is the bare chasis of the truck in the video on the turn table

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Nice picku! :thumbup: Looking forward to seeing the new finished version.

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Wow, great moc! I really like how the chassis looks simple and compact. I've never seen a trail truck capable of spinning PP wheels before. :laugh:

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DUDE ANDY! Excellent creation! i hope you make some istructions for the suspension! :thumbup: :thumbup: :thumbup::cry_happy:

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I am currently fine tuning version two with the gearbox. It is fully functional, but it is ugly. When I get it ready to present, I may make instructions. It shares so many of the same characteristics that one set of instructions may suffice for both models.

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Very nice Truck. I like it a lot, especially this beautiful design.

And video is also cool)

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Hey Andy, thanks for the response. I have been very eager to start building your TrialTruck, so with the few pictures on brickshelf, I have built most of the front axle, and I have started on making the rear axle. I am still a bit puzzled to how you set up the motor-mounts, and top-link securing part. I do plan to edit your steering on your front axle with a M-motor, and a 8-40 gearing. Also, I have somewhat of a clue on the chassis, but I'm not crystal-clear on how to build it. I might just wait until you have completed your 2-speed sariel-style gearbox. I sure hope the high-gear ratio is powerful enough to make it through dome flat dirt. And please make sure you put a remote-shift function using a linear actuator:)

Once again, I am amazed on how well you put the 4-link in along with RC buggy motors & Power Pullers!!!

I wish you the best of luck on your development of this project!

Please email me some more quick photos of how the top axle links are attached, and secured, and sone photos of the basic structure holding the RC buggy motors in place!

Thanks for your time!

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The top link mounts on the axle are 3 studs apart and on the bottom are 9 studs apart. The top link mounts on the chasis are seven studs apart and the bottom ones are 5 studs apart. There are five studs between the lower and upper links. This geometry is the same as I have used on all of my recent trial trucks. There is no caster angle change with suspension cycle and the caster is set to 0 degrees. You can adjust the mounting location of the upper links to create caster angle, but this hurts pinion angle. Here are a few pics of v2 that has the same link geometry and a vid of the gear shift mechanism. V2 will not be using PP tires, but will use unimog tires. It has enough power in high gear to drive through my grass. This should be enough to drive over any rough packed surface that is reasonably level. Low gear will spin the tires an rough pavement.

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The top link mounts on the axle are 3 studs apart and on the bottom are 9 studs apart. The top link mounts on the chasis are seven studs apart and the bottom ones are 5 studs apart. There are five studs between the lower and upper links. This geometry is the same as I have used on all of my recent trial trucks. There is no caster angle change with suspension cycle and the caster is set to 0 degrees. You can adjust the mounting location of the upper links to create caster angle, but this hurts pinion angle. Here are a few pics of v2 that has the same link geometry and a vid of the gear shift mechanism. V2 will not be using PP tires, but will use unimog tires. It has enough power in high gear to drive through my grass. This should be enough to drive over any rough packed surface that is reasonably level. Low gear will spin the tires an rough pavement.

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Thanks for the images! I now have the front axle completed with the modifications for the M-motor! I also have the rear axle finished too. I will start on the frame now that I have a idea of how it was built. I was planning on using the 8110 tires, mounted on black rims too. Thanks so much for your help

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Just got back from the park and my first outdoor test of version two. It is not all "duckies and bunnies". There are a couple of issues, but the transmission and gear shift mechanism are not giving me any grief.

1)High gear (3:1) is a little too weak. It is only good for hard packed mostly level surfaces. It will travel along OK for sometime on rough surfaces, but the longer the motors are under this kind of duress they start to loose power. It must be something with the v2 receivers heating up and safety limiting. Low Gear(8.3:1) is great. I tried PP tires with the high gear and there simply isn't enough power to gather any speed.

2)Adjustable drive shafts fall apart over time when you pick up speed.(they casued some trouble on v1, but now it is worse)

3)Have some gears popping in the axles.(had this issue on v1)

It managed a pretty wicked hill climb despite the less "grippy" tires. I may try a 5:1 version without a transmission and see if the power is adequate. So far it appears that v2 is not necessarily a leap forward from v1. More complex and interesting, but lacking in the performance department. Each gear interchange eats up some efficiency and this version has an extra set of geas over v1. :hmpf_bad:

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