Jackal

[Jackal]

i had decided to switch to the Atomic carbon CR2 for next season and started to collect the necessary parts together, whilst waiting for the nose section to arrive i did the 4th gear mod and prepared the rest of the CR.

but then i saw the Aluminium chassis and the 4 gear plate and thought i would wait until those came out. so with everything ready and having a couple of days free i started playing around with Autocad and pro engineer.

one thing led to another and i sent the drawing to a laser company and they sent these back

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So off to the milling machine and a few hours later we have this

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Now this is a prototype so a couple of errors were spotted but not enough to stop me carrying on.
will post more later

[Jackal]

I started to assemble
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as a temporary measure i dremeled the original battery holder
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using the rear end of the cr i attached to the chassis and then removed the centre bracing, the reason for this will become clear later
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[Jackal]

attached the complete front end exactly the same as the cr2
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[Jackal]

the gearbox, when i started the design i made provision for the cr gearbox to be attached, however i also drew up a aluminium internal 4 gear box in pro engineer, to get this box CNC milled as a one off would be expensive and there was no guarantee that the car would justify it, so i had a problem, i didn't want to use the CR box as the idler gear mod is a bit exposed and to have mounting holes for both boxes was not practical, i have however an S2 4 gear box, a bit of measuring and adjusting the pro engineer file would allow me to use this S2 box and when the new box is made it would drop straight in.

first job was to strip and clean the S2 box
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ready for closing
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attached to chasiss
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I modified an existing CR shock tower to fit to the car, the new planned box is designed to allow the Losi tower to bolt straight in without mods.
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however a quick check with the S2 tower and it fits without moving the geometry around too much so i decided to use that

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[Jackal]

Thats the car pretty much assembled so on with the fitting out, pretty standard stuff for a 2wd, speed passion ESC, Orion Vortex 6.5, Trakpower "dark" saddles, KO standard size servo, a half height one would give more space but i managed to squeeze it in without problem
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[coolcars782]

Looks very nice Jackal :drool:

[Jackal]

Bodyshell and wing, i had an old S2 wing so shoved that on, managed to fit a losi shell with a bit of cutting but needs a bit more investigation, i had an old shell belonging to another racer which i somehow had possesion of so rather than paint some thing quickly i put it on to test run.
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weight is 1650g that is without any extra weight added, tomorrow it gets its first run so we will see. any feedback gratefully received

[Jackal]

Looks very nice Jackal :drool:
Thanks

there are a couple of bits i forgot to mention, although the chassis is flat it is planned to curve the "wings" up to give a little more clearance, weight split is 65%/35% setup as per AC CR2 except for the gearing as the S2 uses associated gear so we have gone 84/21 to start

[coolcars782]

How do you thnk it will handle differently?

[Jackal]

in theory it shouldn't be vastly different, i assume the different internal ratio of the associated gears will mean the drive might be different, the main plus is the weight is all low which should help.

[Battle_axe]

where did you get the parts laser cut?

[Jackal]

local sheet metal company, be warned though, i had a friend of a friend make contact as they had a lot of work done by them, it didn't mean i got it cheaper, rather they agreed to do it, due to an error on my part mixing imperial and metric units i nearly got a 140" wide chassis it was only because the friend went to collect something else and the guy mentioned they couldn't do "that car chassis" until they got some more material!!!

[Battle_axe]

local sheet metal company, be warned though, i had a friend of a friend make contact as they had a lot of work done by them, it didn't mean i got it cheaper, rather they agreed to do it, due to an error on my part mixing imperial and metric units i nearly got a 140" wide chassis it was only because the friend went to collect something else and the guy mentioned they couldn't do "that car chassis" until they got some more material!!!

oh ok will look for somewhere else though

[Jackal]

i contacted a couple of companies, basically they will cut what you send them so make sure its correct!, cost wise a one off like this will be around £40-£50, if they have to do any alterations to your program than it will cost more, if possible do the drawing in a cad package that they use and a useful tip try to make out you will be following the prototype with a large order:D

[Battle_axe]

i contacted a couple of companies, basically they will cut what you send them so make sure its correct!, cost wise a one off like this will be around £40-£50, if they have to do any alterations to your program than it will cost more, if possible do the drawing in a cad package that they use and a useful tip try to make out you will be following the prototype with a large order:D
ok thanks i will do :) may just mill my chassis by hand

[Jackal]

A succesful first run, 3 rounds and a final without anything breaking or falling off!!.

a couple of changes, fitted the losi a2113 pivot block which gives a slightly wider track as the driveshafts were catching on full travel, bonus of this it allows the use of the xx4 rear brace.

need to mill the motor slot a little more as i couldnt get full range of pinion spur combinations.

changed the rear shock bodies as for some reason i put on xxx4 ones which are slightly longer and caused the shocks to bottom before the chassis

weight distribution seemed good no more was added as the car jumped flat, track was wet and the car had a tendency to want to swop ends on acceleration from a corner. steering is agressive and need tuning down

[Trish]

Nice Thumbscrews :)

[Jackal]

Only the best:thumbsup:

[Jackal]

i have now fitted the cr box so now its an alloy cr2!, the weight is now 1620 with no added weight, distribution is 62/38, more testing this week