has anyone made a nitro rc into a crawler??

[B-Nad]

i have been thinking of making one but i dont know if it has the torque??

 

[retarded pilot]

from all i have "read" its not a good setup, it will fry/overheat your clutch...electric sounds much better suited for crawling

 

[NCNitro]

Nitro is not good for crawling for several reasons. You need to keep the rpms of the engine up to keep the clutch engaged, which means you are going to melt clutch shoes and overheat engines. You just dont have the same throttle control to ease on and off the throttle with a nitro as you would with electric. Then reverse with a nitro is not a precission function by any means, it is much easier with electric. You wanna crawl, just go electric.

 

[Lessen]

If you REALLY wanted a nitro crawler the best way (IMO) to do it is with the O.S. FS26SC 4-stroke car engine. They can handle being at low rpm and idle for a much longer period of time. They don't load up with fuel then bog down and stall like our standard 2-strokes do. Then it's just a matter of designing and building a tranny with enough gear reduction to allow super low speeds w/o burning up the clutch. That's a pretty tall order. I think it would be a feasible project though. There would be other issues to address such as engine cooling and I'm sure others would come up but I think it could be done.

 

[Coach Z]

Lessen is right, you'd need some crazy low gearing so that you could get the clutch to fully engage and lock to the clutch bell rather then just burning up. It would be cool as hell if you come up with a way. Maybe a planetary gear like inside of a spin start wand of a prop gearing set????

 

[Lessen]

one word.. Clockwork. Take a look at how the gear reduction is done inside of a clock. a small pinion meshes to a substantially larger spur. That spur turns an attached pinion which inturn meshes another large spur/pinion combo... repeat as necessary. That particular engine revs from 2k to only 22k. You need to gear it so that the rpm of the clutch engagement point matches the absolute slowest the truck would roll. so if the clutch engages at 2400 rpm (I have no idea if that's even a relatively realistic range) then you want to gear it so the truck rolls with zero clutch slip at 2400 rpm with a speed of say.... 1in./sec (I'm just pulling numbers out of my ass here). With gearing like that you would have MAD TORQUE. Not to mention 4 strokes produce more torque per displacement than 2-strokes and better fuel economy.. Plus, it'll sound badass too

Son of a bitch.. I think I want to do this now

 

[Coach Z]

Now you've gone and done it.... convinced yourself its a good idea!

 

[Lessen]

Now you've gone and done it.... convinced yourself its a good idea!

somebody PLEASE talk me out of it! heh

then there is the issue about reverse. I don't know if any mainstream r/c has a super reliable reverse. I know HPI came out with a reverse module for the Savage but I've never really read/heard about how reliable it is. But at any rate, these are designed to appease the mainstream market that wants it for it's convenience. In a crawler, reverse it absolutely necessary. It would have to be ultra reliable and precise. No corner cutting here.

 

[HeartBreak]

Savage reverse module; as long as your at a standstill (holding brakes) the module is extremely reliable. I've gotten 3 gallons through mine with zero problems. It's pretty much clutchless, with a super-smooth engagement. It's a real work of engineering art.

If I were to build a nitro crawler, I'd base it around a savage transmission with a reverse module. I don't know how you would lock out second, other than tightening down the shift point adjuster all the way.

 

[SMaxxin]

somebody PLEASE talk me out of it! heh

Nitro only sounds good going fast, and you can't beat the durability of electric!

 

[B-Nad]

last nite i redid my gears in my tranny and they are pretty low but not the best.... today i took it out to my local creek (it is only about 9 inches deep at max and i waterproofed all my electronics) it is filled with pieces of concrete and bricks and i crawled over those pretty easily also i have soft suspension and now when i hit the ez start button both of the glow plug and engine light come on but it doesn't crank or anything and its not stuck at TDC any ideas of what has happened????????

 

[Lessen]

Nitro only sounds good going fast

Dude, you can't seriously say this doesn't sound cool as poop at idle. I think the best part is when it comes to idle from higher rpm

http://www.youtube.com/v/m38Y_xGSjWo&rel=1

I don't know how to get this clip in here.. just click the link :shrug:

 

[HeartBreak]

I've seen the OS 40 in a buggy in person (I was the one that installed it for a customer when I was working in a LHS, with a 2 speed). Massive torque. We're talkin' skid marks, tires fallin off the rims kinda torque. Just awesome sound.

 

[hamz9561]

At my old LHS, a customer put an OS .32 in an original Revo Chassis and is using it as a crawler. Don't know how well it works though...

 

[Lessen]

There's quite a bit if discussion on this topic in other forums. if you google "nitro rc crawler" you can find a lot. I started looking into other possible engine choices since I don't think it would be necessary to have 22k rpm but the FS26sc is the lightest 4 stroke that O.S. makes. It just makes sense. The O.S. Wankel would be great for center of gravity (sounds cool as poop too!) but at $450 it's not very cost effective vs. a $200 FS26SC. Besides, it's boasts like 1.27hp which is totally unecessary and rotaries generally don't make as much torque per displacement as conventional pushrods. Even though your torque is really coming from the gearing. There is also the Surpass 30 which is cheap @ $160 with a top end of only 13k and the same peak HP as the 26SC but at 10k rpm instead of 17K. It's slightly heavier but the biggest issue is the intake placement. It has an updraft carb and the intake is actually downward facing right behind the backplate. If I were to build a nitro crawler I'd want the intake up higher so I could more easily (and without creating too much restriction) put an extension on it to keep it out of standing water.. Hey, if you're gonna build a crawler.. build a crawler However, I suppose if you're already building a one off tranny you might as well make a custom intake manifold too.

At my old LHS, a customer put an OS .32 in an original Revo Chassis and is using it as a crawler. Don't know how well it works though...

I would imagine it would work "o.k.". But he's probably killing his clutch. Besides, it's still not really a crawler. IMO an MT that goes slow doesn't equal a crawler. Can it crawl? yes. but is it a crawler? no.

 

[B-Nad]

"""""""If I were to build a nitro crawler I'd want the intake up higher so I could more easily (and without creating too much restriction) put an extension on it to keep it out of standing water.. Hey, if you're gonna build a crawler.. build a crawler However, I suppose if you're already building a one off tranny you might as well make a custom intake manifold too."""""


i did that i made a custom snorkel for mine u can see it in the little video i made http://youtube.com/watch?v=g4GdMEsFU3I:yes:

 

[Lessen]

link no good bud

 

[B-Nad]

[ame]http://youtube.com/watch?v=g4GdMEsFU3I[/ame]

sorry