Nitro Crawler (Update page 5)
 

Hey,

I wanted to have a stab at a Nitro Crawler. I have tested it and it works. Will have video up soon.

Specs:
Axial Axles
Axial X Trail Chassis
Moabs for the time being
Toki 1cc NB16 Engine
NB16 Gearbox (4-1ish)
R2 Gearbox

Couple pics.

http://i491.photobucket.com/albums/r...9/PIC_0021.jpg

http://i491.photobucket.com/albums/r...9/PIC_0020.jpg

http://i491.photobucket.com/albums/r...9/PIC_0019.jpg

http://i491.photobucket.com/albums/r...9/PIC_0018.jpg

http://i491.photobucket.com/albums/r...9/PIC_0017.jpg

http://i491.photobucket.com/albums/r...9/PIC_0016.jpg

http://i491.photobucket.com/albums/r...9/PIC_0015.jpg

Sorry for the blurry pics.

Feel free to comment.

Matt

Congrats on getting everything crammed in there....looks like it'll work for ya.

Cheers. It just about fits in. One of the main requirements was that it fit under a 10th shell.

Should have a video up very soon.

Matt

I can't resist looking every time I see a "I'm building a nitro crawler" thread.

At least this thread is different from the norm - there are actual (albeit a bit blurry) pictures of a rig resembling a crawler that actually has a nitro motor mounted up, and the output actually has a clutch installed, that is really mated to some kind of transmission/transfer case.

This is the first time I can remember someone has actually "made good on their threat" and really built something. Props for that Matt, and good luck to you.

I'm Interested in a few things personally, please post back if you can:

1- Clutch type, how you set it up, and how long it takes you to burn it up?
2- Is the brake tied to the throttle servo like a normal set up, or do you have seperate control of the brake to hold you on hills?
3- Motor temperatures during a run, and how long it takes you to burn up a piston or head? (I notice there is a fan mounted behind the head, so it looks like you've at least thought about keeping temps in check)
4- How you pressurize the fuel system to keep it running during severe climbing, descending, or sidehilling? (Or does a stock set up suffice?)

I'm not trying to knock you here, there are just some inherent problems to overcome when attempting a nitro powered crawler using conventional technology and I'm curious how this project is going to perform for you. I'd love to see video of it running...

Nice job.

Is the fan you have enough to keep temps down? Can you channel the air in and around the heads with some plastic shrouding and cut the body you plan on using?
Are you considering a marine head for the nitro motor to aid in cooling it with a small electric pump and radiator setup? Somewhere I saw a post on RCgroups.com where someone had done that to a Tmaxx.
Can you run it rich enough to lower head temp?

Mike, Thanks for the post. I thought I would already have a new a**hole by now but everyones been nice.

The clutch that comes on the NB16 is not up to the job, we messed around with that for a while and then found out that a traxxas two shoe clutch fits. Got the traxxas clutch shoes installed with a tighter spring.

The disc brake is tied to the throttle but it is on the first gearbox so it spins at the same rate it would on the 16th car. I will probably look into a clamp/parking brake in the future. The brake ends up being very proportional and precise. There is so much gearing in the truck that it pretty much holds itself on hills but does roll back when at idle.

The engine is cooled by a fan running off the 6V pack, I thought I would need like 5 fans but one directly seems to do the job. I havent burned myself touching the motor yet:lol: The amount of air that is produced by the small fan is amazing and probably not far off the normal air cooling of the car moving through the air.

The pressurising (sp) of the tank is done in the usual way and as long as you keep half a tank or more of fuel, The pickup is always working. I need to have an extra coil of fuel line in somewhere so that it will run upside down long enough for me to run over and turn it back over.

I realise thats its never gonna be a comp crawler but I sure am gonna have fun with it.

Matt

The electric fan seems to be up to the job, I dont have a temp gun so I dont know exactly what temp it runs at but I do check it about every 3 mins or so. Any other type of cooling would take up too much room so if I need more, I will add another fan. The air doesnt have a chance to miss the head as its so close.

Matt

Finally somebody built one, pretty cool! I like different stuff. Thought about building a nitro scaler just for kicks, but it was only a thought.

thats pretty kool man. ive seen people build gas crawlers before but your looks every good. everything seems to have a real propose. looks good i need to see a video asap!! lol

daleo

I cant wait to see a vid this looks like it might do the trick. Of course it will make the sport much louder.:shock:

Oh yeah its loud! Pi**ed off most of my crawling buddys on the test run. :ror:

Matt

Gas Crawler
 

x2!

I like the emphasis you placed on trying to keep the CG low and a forward weight bias. This is the best looking nitro crawler to date"thumbsup"

video of it "CRAWLING" ?


not bashing

looks good though. "thumbsup"

i'm sitting here tipping my head like a german shepard looking at someone after hours...

gear reductions...
cooling fans...
damn m8 you just got this thing wrapped up tight, tucked better than a betty in singapore.
"thumbsup"


get us some vids bro !

i always wondered why nobody has gone liquid cooled heads like the boats do.

:shock: Video please...

Kudos.

See how much better these threads turn out when someone actually has something to show without just being an ass hat about what they are "going" to built. Waiting on the video!!!!"thumbsup"

Looks like it should work good. Not really familiar with nitro's but can you make them have nice smooth throttle control like an electric?

Digital throttle servo

at least that is what helped on my Nitro Rustler "thumbsup"

but it will never be as "smooth" as a electric... IMO