Kraton First ramp action ever, great day but a couple issues.

[chrisexv6]

Son got on my case to build him a ramp (because, you know, I wouldnt have fun at all .... ), so today thats what we did!

He broke a shock end during the learning process but after a quick fix with some spare HPI Savage parts, he really got the hang of it. Many more land flat bottom down than cart wheel or land upside down.

It was a fun couple runs through the batteries, but of course there was some carnage:

TBone Racing front bumper - I think its the "Thrasher" model, it has a flat plastic piece between the bumper and the plastic block that mounts over the lower hinge pins. We broke the flat plastic piece (learning = lots of front down landings...) Ddoes anyone know what type of plastic is used for it? Since its pretty flat Im thinking I might be able to make my own, just wanted to try and use whatever is closest to "factory" for it.

Not necessarily carnage, but a question - we can see where the skid plate is hitting the ramp before the truck takes off. So, the suspension looks like its bottoming out. The ramp was made with a 45 degree angle from the top and a piece of fiberglass wire fish to connect it to the bottom of the ramp. Did I make the angle too extreme? Is it an issue with the shocks? Both?

Went to run a third pack through it, but saw a nice spark and then nothing....turns out the motor mount got loose which caused the mesh to go bad and the pinion ejected some of its teeth. So we finished for the day lol

Thanks in advance.

-Chris

 

[Jimbobjr]

TBone Racing front bumper - I think its the "Thrasher" model, it has a flat plastic piece between the bumper and the plastic block that mounts over the lower hinge pins. We broke the flat plastic piece (learning = lots of front down landings...) Ddoes anyone know what type of plastic is used for it? Since its pretty flat Im thinking I might be able to make my own, just wanted to try and use whatever is closest to "factory" for it.

I’ve been making my own bumpers out of kydex. It can be found on eBay and Amazon. The main bumper part you want .130” for the piece you broke I think it’s .09”. With a heat gun you can bent it into almost anything. Neat stuff...

 

[GRC]

The ramp was made with a 45 degree angle from the top and a piece of fiberglass wire fish to connect it to the bottom of the ramp. Did I make the angle too extreme? Is it an issue with the shocks? Both?

So it's 2 flat sections? A ramp with a uniform curve would be ideal. Stiffening shocks and raising ride height might help.

 

[chrisexv6]

So it's 2 flat sections? A ramp with a uniform curve would be ideal. Stiffening shocks and raising ride height might help.

No it's curved.. Used this video:

 

[GRC]

Using a single radius for a uniform curve would be better. The video basically connects two flat sections (*and then draws a curve to connect them)

 

[chrisexv6]

Using a single radius for a uniform curve would be better. The video basically connects two flat sections.

I made the current on the sides then used two thin pieces of plywood to follow it as the deck.. It folded perfectly, there is no straight part that I can see. Will get pics later.

 

[GRC]

Here's a video to illustrate. The curve for the side pieces should use a fixed radius for a uniform curve, like drawing a circle with a compass. So use a string to draw a circle around a single fixed point. A shorter string will make a steeper ramp, a longer string will be less steep. Adjust the length as needed depending on what size wood you have and what launch angle you want (45 degrees). The ramp in your video is not a uniform curve, it's flatter on the ends and more curved in the middle. It creates a section that can cause you to bottom out. A uniform curve will not have that problem (unless you make it too steep). See @2:00

 

[chrisexv6]

Here's a video to illustrate. The curve for the side pieces should use a fixed radius for a uniform curve, like drawing a circle with a compass. So use a string to draw a circle around a single fixed point. A shorter string will make a steeper ramp, a longer string will be less steep. Adjust the length as needed depending on what size wood you have and what launch angle you want (45 degrees). The ramp in your video is not a uniform curve, it's flatter on the ends and more curved in the middle. It creates a section that can cause you to bottom out. A uniform curve will not have that problem (unless you make it too steep). See @2:00

I see now!

Luckily we built it with screws so I should be able to tear it down and adjust..

Thanks again.

-Chris