Why isn't Nitro an option on RC Crawlers?

[kurpis]

What types of specific things couldn't be done if a crawling rig was run by Nitro engine?

I really am interested in learning all the ways performance would be inhibited & why that is the case.

I know these are dumb questions for all the RC veterans on here, but I'm a newbie and would rather ask and know than be a silent poser.

Every answer will be read and appreciated.

Thanks!

 

[Joshs4x4toyz]

A few things come to mind that I wouldnt consider it at all, unless just busting around the house, or just wanting a different little project.

1) No low speed control at all
2) Would never be able to deal with the noise trailing lol.
3) Would need to be watercooled resulting in more weight/room

There are a few nitro builds around the forum. Some have been abandoned, some were completed. You may just want to search around and youll find them. I havent seen an actual nitro scaler build on the trail though. Like I said would be a neat little project but it would definitely struggle actually crawling around.

 

[Dezertdirt]

Interesting question, I'm curious about this too. The only reasons that I can think of are:
1. they would raise the cg of the crawler too high making it tippy.
2. Nitros are high reving meaning that there power band is at high rpms and so gearing it down might not be easy or possible.
3. They might ruin the scale look of a body.

I'm all but sure that there are other reasons that I just don't know.

 

[high plains drifter]

I would think that the "carbureted" aspect would play in here as well. I know I'd stall my nitros when they were upside down or at extreme angles sometimes.

 

[rampage]

Torque. Small nitros have none. Look at airplane engines and this becomes painfully clear. You've got very small electric motors turning 12-14" props when your average 40-size nitro motor is happy with like a 10" prop..

If you were going to do IC for a crawler you'd probably want to look at a small water-cooled gas 4-stroke. Nitro 2-strokes are happer moving fast at high RPMs.

Wasn't there a company that made a small nitro 4-stroke for crawlers?

 

[rampage]

I would think that the "carbureted" aspect would play in here as well. I know I'd stall my nitros when they were upside down or at extreme angles sometimes.

That really depends on the engine. Airplane guys run their engines at 90* and inverted all the time. A good motor will generally not have any issues running inverted. Infact most 4-strokes have inverted down-draft carbs by design. But when you're talking crawlers there's really nothing stopping you from going fuel injection. Or at least a pumper. But that starts to get ridiculously expensive.

 

[rampage]

https://www.youtube.com/watch?v=loBNZIbFEgw

This is what I thought I saw earlier. Bangood has them.

Not only do you need to actually figure out how to squeeze it in there but you also need to figure out a throttle servo and a gearbox with reverse, which would require another servo. And as you can see from the video, even with a 4-stroke it has practically no torque.

 

[kurpis]

https://www.youtube.com/watch?v=loBNZIbFEgw

This is what I thought I saw earlier. Bangood has them.

Not only do you need to actually figure out how to squeeze it in there but you also need to figure out a throttle servo and a gearbox with reverse, which would require another servo. And as you can see from the video, even with a 4-stroke it has practically no torque.

Assuming that price wasn't an issue, is it theoretically possible to create a nitro or gas crawler that performs as well as an electric?

 

[rampage]

Assuming that price wasn't an issue, is it theoretically possible to create a nitro or gas crawler that performs as well as an electric?

With currently-available stuff you can buy on the retail market? Probably not. You just don't have the super-fine low-end control and torque that you do with an electric. The immense low-end torque and the super-fine low-end control are the biggest advantages of electric, and none of the IC stuff comes close.

It can be done, it just can't be done as well as electric. It'd be a super cool project but in the end I think the results would be disappointing.

 

[rampage]

Here's a video with the build I posted earlier actually out wheeling and it's not AWFUL but it does demonstrate the lack of torque and the lack of low-end control.

But it is cool.

https://www.youtube.com/watch?v=KrxEOP3rnqc

 

[TheLetterJ]

I'd think the lack of instant reverse and drag brake would make it a pain to drive.

 

[high plains drifter]

That really depends on the engine. Airplane guys run their engines at 90* and inverted all the time. A good motor will generally not have any issues running inverted. Infact most 4-strokes have inverted down-draft carbs by design. But when you're talking crawlers there's really nothing stopping you from going fuel injection. Or at least a pumper. But that starts to get ridiculously expensive.

Ah... dunno why I didn't consider airplanes. I guess that my nitros would get starved between the carb and the fuel tank. The longer the fuel line, the longer it would stay running while upside down.

BTW That video is really cool! Reminds me of crawling in my full-size Jeep that has a standard transmission... riding the clutch lol.

 

[coffeeaddict17]

these guys did it a few years ago on YouTube, but I'm not sure its ever really caught on. Appears to be a lot of work.
https://www.youtube.com/watch?v=nFXpQ5hCerg

 

[OSRC]

I've got a water cooled .15 motor with a water pump and radiator attached to a Tamiya 3 speed trans. The chassis is complete, but I haven't finished the project yet. Been sitting on it for a while.

Not practical in any way, I just thought it would be a fun experiment.

 

[Greatscott]

Nitros have been used for crawlers, but it is very impractical for a number of reasons.

1. Why? At crawling speeds you have more power and run time with electric.
2. The sound of nitro in fast RCs isn't bad, but they are normally a good distance away from you. Unlike fast trucks, crawling is an up-close and personal kind of RCing, having the nitro incessant whine and exhaust constantly at your feet would get old, fast. Crawling is also a most social form of RCing, the people you are crawling with will soon get tired of the noise and exhaust.
3. Nitros piss fuel as part of the cooling and lubrication, which means pissing fuel all over the rocks you are trying to crawl on.

 

[JatoTheRipper]

Nobody sells a nitro crawler because it wouldn't sell well. They are loud and lack the torque and low speed control needed on a crawler.

But people have been them many times. One of the magazines even built one back in the day. I think it was RCCA, but I'm not positive.

What about a crawler that has a nitro engine powering a generator to power the electric motor?

<iframe width="560" height="315" src="https://www.youtube.com/embed/nFXpQ5hCerg" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
https://www.youtube.com/watch?v=nFXpQ5hCerg&feature=emb_title

This one has a 4 stroke engine.

<iframe width="560" height="315" src="https://www.youtube.com/embed/bakq5d81ECU" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
https://www.youtube.com/watch?v=bakq5d81ECU

<iframe width="560" height="315" src="https://www.youtube.com/embed/3T2cHr5i3DU" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
https://www.youtube.com/watch?v=3T2cHr5i3DU

<iframe width="560" height="315" src="https://www.youtube.com/embed/dZJy9U4Mf-0" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
https://www.youtube.com/watch?v=dZJy9U4Mf-0

Apparently embed isn't working at the moment for me.

Axial made nitro engines before the made crawlers. They just never combined the two.

https://www.rccaraction.com/axial-january-releases-21rr-1-engine-rock-crawler-esc-and-2-4ghz-radio/

 

[kurpis]

Here's a video with the build I posted earlier actually out wheeling and it's not AWFUL but it does demonstrate the lack of torque and the lack of low-end control.

But it is cool.

https://www.youtube.com/watch?v=KrxEOP3rnqc

Maybe Its because Im a newbie, but I think its really cool!!!!

 

[kurpis]

these guys did it a few years ago on YouTube, but I'm not sure its ever really caught on. Appears to be a lot of work.
https://www.youtube.com/watch?v=nFXpQ5hCerg

Great video. Thx for sharing.

 

[kurpis]

I've got a water cooled .15 motor with a water pump and radiator attached to a Tamiya 3 speed trans. The chassis is complete, but I haven't finished the project yet. Been sitting on it for a while.

Not practical in any way, I just thought it would be a fun experiment.

GO FOR IT BRO!!!!!! I'd love to see it.

 

[kurpis]

Nitros have been used for crawlers, but it is very impractical for a number of reasons.

1. Why? At crawling speeds you have more power and run time with electric.
2. The sound of nitro in fast RCs isn't bad, but they are normally a good distance away from you. Unlike fast trucks, crawling is an up-close and personal kind of RCing, having the nitro incessant whine and exhaust constantly at your feet would get old, fast. Crawling is also a most social form of RCing, the people you are crawling with will soon get tired of the noise and exhaust.
3. Nitros piss fuel as part of the cooling and lubrication, which means pissing fuel all over the rocks you are trying to crawl on.

I never considered the pissing fuel on rocks problem. Is there any way around that?