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savage rockcrawler

10K views 16 replies 11 participants last post by  towie964 
#1 · (Edited)
Project Description
just to try something different, and to use up some of the spares i have left over from the freightliner project, i'll make a savage rockcrawler. i know people say clod axles are the best, but i'm not going to pay for them when i have existing options for free. for you sceptics out there, watch me try.

here's the various stages that i can think of at the moment:

1st stage: modify front/rear sections.
a) lock diff
b) make mounts for extra gearing/electric motor.
c) relocate steering servo?
d) double up to make it 4WS if i could be bothered.

2nd stage: modifymiddle section.
a) use left over sections of tvp and chassis braces to make the center section

3rd stage: link 3 sections together.
a) make the tierods the same way other people do.

4thstage:test out suspension oil combo.
a) all the crawlers i've seen have the suspension arms locked. wonder how the handling will be if it isn't...
 
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#2 ·
hardest part is going to be the gearing between the motor to the diff. trying to recycle the gears from the savage 2speed gearbox, i've thought of two approaches. dark green line imply gears on same shaft.

first approach is a horizontally mounted motor (engine mount parallel to TVP), which gives final gearing around 12:1.

will require modify to the diff as shown in insert. possible recycle the gearbox housing and shafts to mount the various gears, and will need to make a tamiya TA style motor plate.


the second islongitudinal mounted motor, final gearing about 18:1.

will need to make two plates to be mounted perpendicular to the TVP, then try to recycle the shafts from the 2speed box.

not sure at this stage if 12:1 or 18:1 is enough for rock crawling... but none the less, the problem to how to mount the gears is partially solved. sorry to those not familiar with the savage layout, the above description probably doesn't make much sense.

BDR suggested to me that he had a 130:1 on his MAXX... seems a lot to me, not sure if it's a typo and should be 13:1?? can anyone confirm the ratio suitable for a crawler?

Edited by: Boutzb
 
#5 ·
Well done boutz! the higher you can get the ratio ie: 130:1 the slower, more capable it will be.. not many people go the savage route on the crawler scene especially a nitro due to keeping it cool, clutch etc.. now if you could somehow work out a way to put a surge tank or resivoir nice n low and water cool it... hmmm!!






pics of RC crawlers...





the SEARCH button is your FRIEND.



As is www.rccrawler.com www.google.com "RC rock crawler" took all the hard work out now all you have to do its cut and paste!!
 
#6 ·
BazzokaJoe said:
What Does a compleat Rockcrawler look like? Please post Pic

i hope the owners of these crawlers don't mind me using their pics. if you are, let me know and i'll pull them off.


jjjrules' crawlers:



BDR's crawlers



foolSp33d said:
Well done boutz! the higher you can get the ratio ie: 130:1 the slower, more capable it will be.. not many people go the savage route on the crawler scene especially a nitro due to keeping it cool, clutch etc.. now if you could somehow work out a way to put a surge tank or resivoir nice n low and water cool it... hmmm!!

i think 130:1 will be too slow. i've confirmed with BDR, and it's a typo and should be 30:1. so i might need to make some adjustments to thelongitudinal arrangement.


i should probably have made it clearer, it's NOT going to be nitro. apart from the cooling problem, there's also the problem with space for fuel tank and pipe.


does anyone know if i can get pinion gears to fit electric motors that have same pitch as the savage spur? not sure what the pitch is off the top of my head.
Edited by: Boutzb
 
#17 ·
BazzokaJoe said:
What Does a compleat Rockcrawler look like? Please post Pic

i hope the owners of these crawlers don't mind me using their pics. if you are, let me know and i'll pull them off.


jjjrules' crawlers:



BDR's crawlers



foolSp33d said:
Well done boutz! the higher you can get the ratio ie: 130:1 the slower, more capable it will be.. not many people go the savage route on the crawler scene especially a nitro due to keeping it cool, clutch etc.. now if you could somehow work out a way to put a surge tank or resivoir nice n low and water cool it... hmmm!!

i think 130:1 will be too slow. i've confirmed with BDR, and it's a typo and should be 30:1. so i might need to make some adjustments to thelongitudinal arrangement.


i should probably have made it clearer, it's NOT going to be nitro. apart from the cooling problem, there's also the problem with space for fuel tank and pipe.


does anyone know if i can get pinion gears to fit electric motors that have same pitch as the savage spur? not sure what the pitch is off the top of my head.
Edited by: Boutzb
Electric pinion to suit Savage spur is Mod 1, I converted a nitro savage to brushless and needed same pinion pitch
 
#8 ·
thanks for the link gumby.


i was thinking maybe the esc, motor and pinion from the E-savage would work.




i've checked, the E-savage have 32pitch pinion, so i'll probably use the E-savage motors, esc and pinions to start things off.



Edited by: Boutzb
 
#10 · (Edited)
easier to draw a sketch than describing it in words. sorry to those who're not familiar with savage, this probably won't make much sense.



in red will be (for now anyway) gears recycled from the 2 speed gearbox, with the lowest horizontal driving the cup that otherwise the
center dogbone will hook up to.

will try not to disturb the existing steering setup and servo location if possible. just chop off bits of the radio box that's not needed.

i'm thinking of putting the batteries between the bulkhead and the bumper, to reduce weight in the middle section. will see how goes.
 
#11 · (Edited)
started putting things into CAD. i've sorted out the upper and lower axle mounting positions into CAD, in green and blue respectively.

upper axle mount will just around the top of the shock tower. not that good a position, will try to lower it after i sort out the steering
servo/motor mounting.

lower axle mount will be making use of the existing holes on the lower suspension arms, the ones parallel to the shock mounting holes.

dimensions based on fully extended suspension, and moab 40series.

 
#14 ·
G'day mate, i would'nt be running the arms in a full droop posi because this WILL pop out ya dog bones then bend you're axles
.


When you do you're link's up remember to double triagulate(sp) them.


And 30-1 reduction is'nt low enough
.


And finally, go and update this on the Pit
, and hurry up because we all want to see this thing crawl
.


Chris
 
#15 ·
B.D.R said:
G'day mate, i would'nt be running the arms in a full droop posi because this WILL pop out ya dog bones then bend you're axles
.


When you do you're link's up remember to double triagulate(sp) them.


And 30-1 reduction is'nt low enough
.


And finally, go and update this on the Pit
, and hurry up because we all want to see this thing crawl
.


Chris
hey chris,

nah, won't be at full droop. will limit the shocks probably by 1 cm to lower CG, maybe more if needed.

yeah, will be double triangulating. lucky me i found a local who's into crawling as well, and have built a few crawlers himself. so i can learn from him, and examine his crawlers.

nah, final thing will be much higher than 30-1

when i am cracking at this thing again, i'll update on the Pit in parallel. atm, i'm busting my chops writing my thesis. and only do some light rc at night to keep me sane.
 
#16 ·
RC Crawlers are cool, but im into the real thing..
 
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