bandi

I KNOW - ELECTRIC CRAWLING IS THE ONLY THING POSSIBLE...

I am not looking for an argumentle discussion about the Electric vs Nitro Issue... Just Project Fabrication...

With That Said...

I have come up with an idea, I believe should work with a Nitro Crawler (which would be for Crawling Only - same as an Electric Crawler - SLOW and STEADY, not for bashing / racing)

I can fabricate an relocated mount for the engine with no problem, and also fabricate a gear reduction Case for the T-Maxx Modified 14t Bell & 72t Spur assembly. I can even add as many reduction gears as I want to get it as low as I need to keep the Engine RPM's up to have the Bell Clutch locked SOLID during all movement.

I found an imformative site on calculation the wheel drive Speed based on each gear size, calculating from the engine to the wheels...

I am going to do some more reading and some disassembling to get information on what the TOTAL Reduction (Bell Clutch Lock-up RPM - The Revo Differential Ratio - Transmission Output Ratio - T-Maxx Reduction Gear Output Ratio and how many sets of reduction gears I will need to match the Electric Crawl Speed at the wheels...

I know it is possible to get the power and speed where it needs to be without the Bell Clutch slipping the hole time while going slow.

As others here have said, A Real 1:1 Crawler works, So can A nitro, and as with a 1:1, you just need the proper gearing and cooling system set up. All which is possible. Although I have not seen this created / built yet (that I can find information on)...

I own 2 Revos, and one will be left stock, the other I will be modifing for this project...

I First will need to get the gearing calculated and built and tested on the stock Revo Chasis...

Second, I will build a chassis and suspension system to keep the CG down and give the proper wheel base to match an Electric Crawler.

annie_himself

A crawler is a more simple design, so why clutter it up?

bandi

Annie_Himself...

"A crawler is a more simple design, so why clutter it up?" I am not sure what you mean... Electric vs Nitro??? Gear reduction not really needed in a Electric / Nitro Crawler??? I am not bashing, just curious... and i did not get your meaning...

I don't have Any Ideas on how not to clutter things up with a Nitro Engine Setup... Not that I feel a Gear Reduction box between the engine and trans is clutter... if this is what you are refering to...

Its a Nitro Engine setup.... The bell clutch does not engage till high RPM's, So I need to compensate for that by adding a reduction gearing in front of the trans so that the output at the wheels at the engines high RPM's is SLOW...

Other than that... it will be a standard crawler using solid fixed Revo Axles and Shafts... Oh yeah...And Nitro powered...

platinumchopper

good idea...go for it!

APEXdriver89

sounds good to me...do it and plz tell us the results...it would be nice to shut up all these guys that think that only electro's can be crawlers![>:]

clodbrett

Anything that moves "Can" be a crawler.. its just that nitros are not known for their supreme efficiency and crawling prowess. With that said, you know that your Nitro engine is going to produce peak torque around 30,000 RPMS VS 2-3k rpms on an electric motor. So you will need to gear accordingly.. and then you will be running your nitro at crazy rpm's for extended periods of time.. generating alot of heat, and burning alot of fuel, so you will have short run times too. I get like 45mins with my clod on a 3000mah pack

but yes, I think your idea would work.. just at a certain efficiency.

_bR3T7

sonixx

exactly what i was thinkin clodbrett, you would need to run some sort of a separate fan for the engine.

mechanicalbob

My Feedback: (49)

As for what engine to run, have you looked at running a[link=http://www2.towerhobbies.com/cgi-bin/wti0001p.pgm?&P=PR&I=OSMG2091] 4 stroke nitro[/link]? they have a good low end torque. Another one to look at is a[link=http://www.osengines.com/engines/osmg1636.html] boat[/link] engine. With this one you can make you own lil radiator to keep it cool, to move the water you could use a [link=http://www.perrypumps.com/]Perry Pump[/link] and this engine has a pull start on it. and both of these engines are low rpm (around 17000) One other idea to kick around is doing a [link=http://www.davisdieseldevelopment.com/gallery/gallery3.htm]Davis Diesel [/link] conversion, it lowers the rpm and adds some nice diesel power. One thing that you might want to think about is your fuel tank. What I mean about this is that as with most crawlers you are going up steep hillls or down them or better yet slidding on your lid. To keep the Nitro mill going at all angles even upside down I use a [link=http://www.shopatron.com/product/product_id=DUB420/101.0]flopper tank [/link], basicly it is an airplane fuel tank. As for gear reduction......what about using a standard T-Maxx tranny, with reverse, the 2 speed, the single disk brake, and then on one of the output shafts have it coupled or geared to a E-Maxx tranny with a Hi and Low setting? So you could change your gearing on the fly with a four channel radio. Any way that was my 2cents worth on this. If you have any ? feel free to ask ??'s or email me at [email protected]

Steve

bandi

Thanks Much Mechanicalbob... Appreciate it very much...

Some great ideas, and more reading for me...
When I get some things together, I will post them...

I have decided to not tear down one of my 2 current revo's...

So I have bought close to 2 more from ebay part by part,
It's nice to get that 0.99 bid on big items... anyway...
I have enough parts do the build up now... with the exception
of specialty items that are not forseen at the moment...

Leroy...

Anomie

You know, I agree. A nitro crawler does have a few issues to work through, but isn't that why it's called a project? Personally, I also like to go outside the typical thinking and try to make something different work for me.

The radiator and liquid cooling idea is also something I have been working on. I found a copper-tubed radiator that's about 4" square, and plan to operate a small pump and reservoir with a pressure relief. I don't know yet if it will work ok, but I'll try nonetheless. It has been fun to design.

OT for a sec, is it pretty nice up there in Ketchikan? My GF and I almost took a ferry up from Bellingham, WA in december, but decided not to because of the time it would take. Now I'm wishing we had checked it out!

bandi

YOU SAID IT... I luv the challenges... best things comes from them...

I am looking into the VP-40SG / VP-30 Pump from Perry Pump, the flow rate is
3.5oz/min... I sent them an email to make sure it will pump water... but it comes
with a fitting to tap into the block to provide the pumping presure to the pump.

I am getting a Traxxas marine head for my Traxxas 2.5R from Tower Hobbies for $18...

Heretique, Where did you pick up that 4x4 rad from...???

Also... Did you ever make up your mechanical water pump...???

Any pictures you may have or take... could you post them or email me with them.... [email protected]...

Thank You...

Anomie

Below is a picture of the radiator which I shot this evening. I found this on eBay, and it is designed to work with a liquid-cooling system for a PC. I have seen many radiators for this purpose, but none that so closely resembled an actual unit. The water pump has gone through a few changes with regard to design, and I have also considered using a mechanical fuel pump from a stock YS engine. I'm not sure how it will handle the temperature. also, I will likely have to machine my own cooling jacket for the head of the engine as they do not make one to fit.

So far, I have no pictures of any further work, as I have been trying to get the motor and trans relationship worked out, as well as body mounts. I'll post more when it's completed.

bandi

That core gives me some more ideas being that is came from a pc... I need to do some more looking into that area....

I did find out a simple thing for my gear reduction, it seems the stock revo push rods for the suspension, are the exact diameter i need for my gear reduction shafts / bearings....

The fuel pump apears to run off the rear of the YS engine ??? that would make starting the engine a litttle hard for my EZ Start...

I wish I had a milling machine to make up a mini waterpump housing, ad some bearings and seals... and water flow....

Leroy...

mechanicalbob

My Feedback: (49)

Well I have a few more thoughts to throw out there. The first has to do with your gearing, If you were to put one of these [link=http://hobby-lobby.com/scaledrives.htm]gear boxes[/link] at each output of the tranny it be a good reduction, Also at the bottom of the link above is a "bow thruster" you could use it to pump water, and use a [link=http://www.minco.com/products/sensors.aspx?id=34]temp sensor [/link] to turn it on and off. As for a psi releif valve for the coolig system you could make one out of 1/8 inch and 5/32 brass tubing, bb and a ball point sping and a lil testing. what you need to do is take a small length of the 1/8" tube and solder it into a 1-1/2 -2" length of the 5\32nd tube then drop in the bb, drill 2 or 3 small holes above the bb then add the ball point spring the cap the 5/32nd tube with a rubber cap "anteanea cap" and a small washer and a zip tie so you could adjust the psi relief by adding a spacer or taking out a lil spring.

Steve

mechanicalbob

My Feedback: (49)

Here is a [link=http://www.dumasestore.com/catalog/product_info.php?cPath=39_79&products_id=303]link[/link] to some gear compounds that are 6:1 reduction and some other interesting things as well.

Steve

lil_man_maas

*** do you do for a living Mechanical Bob holy crap! lol

t-maxx8/4

i know this may sod dumb but i paintball and co2 is really cold and if u can figure out a way to cool ur motor down with that its probably the easiest way..thats if its possible. i am very interested in your project and would like to know the results i will be doing some research to help you with this cause i hate it when people say nitro can't be a rock crawler.[:@]

bandi

I and, I am sure the same goes for MechanicalBob, appreciate any info... you can never have too much knowledge... ANYTHING IS POSSIBLE !!!

I have the parts for the gearing now, I need to drillpress out 3 spurs for the gear reduction to fit bearings on properly...

I have Ebayed enough parts for 2 more revos, so I sould be able to modifiy it in any way...

PS... I don't know if my Wife will let me live thru it tho... LOL... I came home to 6 more Ebay boxes on the table today... AAAHHhhh....

mechanicalbob

My Feedback: (49)

Hello it is me again...I may have over thought this one a lil bit or maybe I have under thought it. Any way I had a idea today that could leave the stock input gears intack and inplace. I will start at the beginning...............Stock Maxx/Revo 1st gear is about 23.85:1 and 2nd is 16.54:1 with the diffs comming in at 2.84:1.......giving 1st gear a final ratio of 67.73:1 and 2nd a final of 46.97:1.........Now if you were to swap out the diffs for a [link=http://www.ketterer.de/englisch/pdf/worm_gear_4747.pdf]worm gear[/link] set up....with a 13:1 ratio........1st gear would be a WILD 310.05:1.........2nd would be 215.02:1..........now a mild one 6:1 ratio......1st would be 143.1:1........2nd would be 99.24:1, on the link they have a few other ratios to chose from, those are the two that I liked the best. With this set up it would be fully locked front and rear and some custom drive outputs would need to be made, and 4 wheel steering. Any way that is my thought of the day.



Steve




Here is a [link=http://www.ketterer.de/englisch/pdf/universal_joint.pdf]U Joint[/link] that will fit the Worm drive above it is at the bottom of the page with a 6mm hex drive.

bandi

Wooozaaa MB... I wonder what the cost of those are... I'll tell you, Crawlers would be loving those ehhh !! Thanks MB...

I look forward to TODAYS MB Post.. !!! =P...

Anomie

You can also check out these [link=https://sdp-si.com/eStore/Select.asp?GroupID=949&SearchPattern=]Worm Drives[/link] from Stock Drive Products. They make these in ratios up to 20:1.

mechanicalbob

My Feedback: (49)

I agree that [link=https://sdp-si.com/]SPD[/link] has some great stuff, but there worm drives are a bit on the steep side of the price curve, and the unints are a bit on the heavyside of things to put in a rc and there size may not allow them to fit.

One good thing about worm gears is that you wont have to run any brakes, the reason is that the worm wheels can not turn the worm screw so when you you stop on a steep hill your truck will stay or topple over from gravity

I have contacted the company that makes the worm drive that I had posted, They are made in Germany. They have a sales office here State side but they dont have these drives so they have be shipped in from Germany. They come in left hand and right hand rotaion and up to a 35:1 ratio. I should have a price break down on the 6:1 and the 13:1 in a few days. I am ordering L/R 6:1 and a L/R 13:1 If I like how they work I will become a distributor and get a few more over here.



Steve

bandi

Nice deal Steve... Let me know how you like eem' when they get here...

Anomie

Yeah, SDP can be pricey. I plan to get a couple of telescoping universals from them, and they are pretty costly too.

The weight is not really something I worry about much, but that's just me. My truck is very heavy and I wanted it as such for traction, but bandi may not want it too heavy.

bandi

Having the weight low on an axle is not a bad thing, compared to the top weight... But the price.... My wife would have something to say about it... [X(]

For right now, to prove my point (or try to) about a nitro crawler, I want to stick to the most stock parts as possible...

I know the Elec's use weights to keep their trucks upright... but that can be added later...