FT What Did You Do RC Today : Caution Offtopic At All Times

[wilmracer]

Does anyone have any experience with fiberglassed foamboard? I've seen a few guys (@wilmracer) use it on big projects before. I'm thinking about using it for some non-rc applications and I'm curious how durable it would be for, say, body panels on a cyclekart? I'm concerned about what mud and flying gravel might do to it, but if it works it could easily knock 50 pounds off the total weight.
A cyclekart is a small racing go-kart modelled after Grand Prix race cars of the early 20th century.
View attachment 158588

Interesting thought. To be honest I think you would need to lay pretty heavy glass (and a few layers at that) for the panels to hold up long term. The light glass we use on our models generally wouldn't hold up well to ground racing and would provide basically 0 protection from a collision.

What are cyclekarts typically fabricated from? Sheet metal? It might be feasible to make temporary panels from FB, cover them with packing tape, spray on some PLA mold release or wax them, and then lay down multiple layers of heavier glass alternating the weave directions. When cured you would have pretty light weight glass panels to use on the cart, but they might still require additional structure.

Bottom line light glass over foamboard probably won't last long in an application like this, and by the time you add enough glass to get the strength/durability the weight savings may not be that much. Just my thoughts. I'd love to see you give it a shot though!

 

[redbarton]

Here's what I did this last weekend...

 

[The Hangar]

Here's what I did this last weekend...

View attachment 158619

Ooh - I’ve always wanted a crawler, and that Trx-4 looks awesome!

 

[The Hangar]

Ooh - I’ve always wanted a crawler, and that Trx-4 looks awesome!

I do have a traxxas slash Vxl and the e revo 2.0 vxl. Those are both fun!

 

[Crawford Bros. Aeroplanes]

Interesting thought. To be honest I think you would need to lay pretty heavy glass (and a few layers at that) for the panels to hold up long term. The light glass we use on our models generally wouldn't hold up well to ground racing and would provide basically 0 protection from a collision.

What are cyclekarts typically fabricated from? Sheet metal? It might be feasible to make temporary panels from FB, cover them with packing tape, spray on some PLA mold release or wax them, and then lay down multiple layers of heavier glass alternating the weave directions. When cured you would have pretty light weight glass panels to use on the cart, but they might still require additional structure.

Bottom line light glass over foamboard probably won't last long in an application like this, and by the time you add enough glass to get the strength/durability the weight savings may not be that much. Just my thoughts. I'd love to see you give it a shot though!

Thanks for the input. They're usually made of plywood or aluminum, but those mediums can be difficult to work with. I've heard of guys using fiberglass over foam for engine covers and whatnot, but I'm not sure if anyone has ever made an entire kart out of it.

 

[wilmracer]

Thanks for the input. They're usually made of plywood or aluminum, but those mediums can be difficult to work with. I've heard of guys using fiberglass over foam for engine covers and whatnot, but I'm not sure if anyone has ever made an entire kart out of it.

One other quick thought... I'm assuming these are gasoline powered, and foam is not a fan gas. Using fiberglassed foam would likely lead to melted structure pretty quickly without a lot of fuel proofing.

 

[whackflyer]

Ooh - I’ve always wanted a crawler, and that Trx-4 looks awesome!

@The Hangar here's your chance to get one! I don't drive mine enough so I'm selling it!

 

[Bricks]

Thanks for the input. They're usually made of plywood or aluminum, but those mediums can be difficult to work with. I've heard of guys using fiberglass over foam for engine covers and whatnot, but I'm not sure if anyone has ever made an entire kart out of it.

Could you use coroplast, not a real weight savings per-say but durable.

 

[redbarton]

I do have a traxxas slash Vxl and the e revo 2.0 vxl. Those are both fun!

Yes, they are. I used to race Slashes many years ago. Here's a pic of my highly modded franken-slash:

I pull this out when I want to go fast and terrorize the neighborhood.

I've always wanted an e-revo and have driven a few, but just never pony'd up for one.

The TRX-4 is a beast. It amazes me with what it can do, even with that heavy body and roll cage on it. I drove it for 3-4 miles this weekend, near St. George, Utah. It was a blast. However, it was almost as much fun to watch my kids driving it. I need to get another crawler or two for the family!

 

[Crawford Bros. Aeroplanes]

One other quick thought... I'm assuming these are gasoline powered, and foam is not a fan gas. Using fiberglassed foam would likely lead to melted structure pretty quickly without a lot of fuel proofing.

Usually there's a tailpipe running out the back of the car so exhaust isn't blowing directly over the foam like it is on a plane.

Could you use coroplast, not a real weight savings per-say but durable.

I've never worked with coroplast, but it's never too late to give something new a try. I think I may end up having to use several materials- light plywood for the big panels and a bit of aluminum and fiberglass for the curves, all laid over a minimal flat bar frame.

 

[Grifflyer]

Usually there's a tailpipe running out the back of the car so exhaust isn't blowing directly over the foam like it is on a plane.

I've never worked with coroplast, but it's never too late to give something new a try. I think I may end up having to use several materials- light plywood for the big panels and a bit of aluminum and fiberglass for the curves, all laid over a minimal flat bar frame.

Coroplast is the plastic material most commonly used in the election signs, it would only work well for flat panels since it can't really curve, so it might make a good replacement for the plywood panels.
Still waiting on the pics

 

[Crawford Bros. Aeroplanes]

Coroplast is the plastic material most commonly used in the election signs, it would only work well for flat panels since it can't really curve, so it might make a good replacement for the plywood panels.
Still waiting on the pics

You'll be waiting for a while, I haven't even started building yet and it should take me a few months haha. Here's a rough outline I did in Sketchup, I needed to figure out how the body was going to sit on the chassis before I started welding things together:

In all seriousness this is getting pretty off topic.

 

[Grifflyer]

You'll be waiting for a while, I haven't even started building yet and it should take me a few months haha. Here's a rough outline I did in Sketchup, I needed to figure out how the body was going to sit on the chassis before I started welding things together:
View attachment 158740

In all seriousness this is getting pretty off topic.

That's really cool!! Are you planning on running an authentic engine or something like a motor bike engine for simplicity?

 

[Crawford Bros. Aeroplanes]

That's really cool!! Are you planning on running an authentic engine or something like a motor bike engine for simplicity?

It runs on a Honda GX200 6.5 hp, it's not nearly big enough for a full-sized engine. It's a go-kart, the wheelbase is only about 60 inches. The idea is to "capture the essence of early automobile racing," hence the vintage designs, somewhat low-powered engines, and DIY backyard engineering. Everyone's limited to the same engine and all the cars are built more or less the same, so no car has a distinct advantage over another. May the best driver win.
Now to find a club in California.

 

[Fluburtur]

I built a 1.3 to 5.8ghz fpv repeater, hopefully that will fix the signal issues that are probably caused by my crossfire and allow me to achieve greater range with my long range plane.

 

[speedbirdted]

So I've just had a thought.

Say I want to build a large multi-motor airplane. The plane has big control surfaces that need big forces to move them. This means big servos which have big amp draw. Now - I'm wondering whether, if the plane ends up having something like 4 escs with their own BECs, will running a bunch of BECs feed more power into the reciever and hopefully prevent brown outs?

Or, should I just go the other route and hook up a big stinkin' LiFe to the receiver to help it out (or a Lipo with an SBEC or a 1s lipo charged to 5v) but then that begs the question of if I have a bunch of ESCs all with their own BECs running back into the receiver (we're not going large enough to get into ESCs that don't come with a BEC) can I just cut the positive/negative leads off the cable running from the ESCs to the receiver and just have the signal wire? Or does nothing I just said make sense?

Maybe I should stick to nitro...

 

[The Hangar]

So I've just had a thought.

Say I want to build a large multi-motor airplane. The plane has big control surfaces that need big forces to move them. This means big servos which have big amp draw. Now - I'm wondering whether, if the plane ends up having something like 4 escs with their own BECs, will running a bunch of BECs feed more power into the reciever and hopefully prevent brown outs?

Or, should I just go the other route and hook up a big stinkin' LiFe to the receiver to help it out (or a Lipo with an SBEC or a 1s lipo charged to 5v) but then that begs the question of if I have a bunch of ESCs all with their own BECs running back into the receiver (we're not going large enough to get into ESCs that don't come with a BEC) can I just cut the positive/negative leads off the cable running from the ESCs to the receiver and just have the signal wire? Or does nothing I just said make sense?

Maybe I should stick to nitro...

It didn’t make sense - to me... But don’t rely on just me, cause I don’t really know much about that kind of thing. However in my research on large builds, I’ve kinda settled on a setup that I’ll do when I get the cash for it. I’m gonna buy an esc purely for the esc - I don’t care if it has a bec or not. Then I’ll buy a large BEC and run a separate battery plugged into the BEC for just the servos. Then, I’ll have a battery feeding power directly to the esc and receiver.

 

[speedbirdted]

It didn’t make sense - to me... But don’t rely on just me, cause I don’t really know much about that kind of thing. However in my research on large builds, I’ve kinda settled on a setup that I’ll do when I get the cash for it. I’m gonna buy an esc purely for the esc - I don’t care if it has a bec or not. Then I’ll buy a large BEC and run a separate battery plugged into the BEC for just the servos. Then, I’ll have a battery feeding power directly to the esc and receiver.

That was my thought, but I'm not sure if having the integrated BEC in the ESC and a separate BEC would do something bad to the reciever. I'm pretty sure the current will run in parallel so I don't think it will be a problem but I would rather not test it by blowing things up

 

[The Hangar]

That was my thought, but I'm not sure if having the integrated BEC in the ESC and a separate BEC would do something bad to the reciever. I'm pretty sure the current will run in parallel so I don't think it will be a problem but I would rather not test it by blowing things up

I don’t think it would be an issue. I’ve hooked up two esc’s which both had esc’s to the same receiver and not had any issues.

 

[speedbirdted]

I don’t think it would be an issue. I’ve hooked up two esc’s which both had esc’s to the same receiver and not had any issues.

Bah why did I not think of it that way! I just realized I hooked up three ESCs to one receiver ages ago via a Ψ-harness and I don't remember it doing anything bad. Of course it isn't something I would do now since differential thrust is too much fun...