the beginnings of weapon X-updates 2/21/2011

[jwscab]

OK, so this is partly rc10 and other makes combined into weapon X.......not sure if this is the right forum, but here goes......as parts get modified and fitted, I'll update the thread. comments, suggestions welcome!!

the idea of this car has been kicking around in my head for quite awhile....just never got around to building it.....until now. I happened to find and pick up an assortment of parts that lend themselves to building this.....

how many different car components can you spot?

[Toasted Coastie]

Man, I can't wait to see this! I like the "X" theme....

You're not ripping off Marvel, are you...?

[shane]

Are these extra parts you have or did you get these parts just for X ?

[jwscab]

actually, the theme IS kinda marvel.....didn't plan it that way, but that is the way it's shaping up. The fiberglass I'm using is a kinda bright yellow, and the wheels will be too.....the body will have some black and yellow too.....

to shane: I ordered some parts specifically for this, based on parts I already had. I tend to get a pile of parts in front of me, and see what I can think to build....in this case, I had the front end parts, and wanted something midmotor. I also wanted something belt drive. Doing some digging and research determined the parts you see. $$ was very important which is why those parts were chosen.(I have way too much stuff and I don't NEED another car, but it is is cheap enough......)

the next major step will be machining/modifying the rear arms, as they are too long and need some other clearances for the rear hubs.

[shane]

Do you do your own machining?

[jwscab]

yeah, if you can call it that. I just have an assortment of hand tools, drill press, belt sander, vises, etc. I also have a lathe which I'm currently in the process of rebuilding, I think one good long night on it and I can finally turn some metal, i just got the last pieces for it yesterday.

with the plastic stuff, it doesn't take much to trim cut and modify. Ideally, I'd like to get a mini-mill, but I might end up setting up a milling attachment on the lathe.

Since I don't have the 'real' tools, I have to get creative with jigs and fixtures, but with enough prep, I can get stuff to come out pretty well. My drill press is pretty new and straight, which helps to make accurate holes.

as back up, for really precise stuff, I can get my dad to machine stuff on a bridgeport at work.

[Mr. ED]

I can't make up which cars you're using parts of from those pics, but overall it look a bit like what I tried to do with the kyosho stinger mk2 I had. would you mind disclosing some details?
Are those rear arms traxxas parts?

[jwscab]

yep, here is the parts list so far, subject to change at any time, based on how things unfold.

front suspension/front end is B2/B3

transmission/bulkhead/rear suspension mounts is traxxas electric 4tec, will include upper shaft with pulleys, spur gear hub(upgradeable to slipper clutch with a kit). belt is HPI I hope, as the diff is a couple teeth more than the original diff pulley, and the HPI belt is a couple teeth longer than the e4tec belt, so we will see.

gear diff is traxxas nitro 4tec with eccentrics and bearings.

outdrives are hybrid traxxas/losi, traxxas half shafts and output yokes, losi axles and xxx? hub carriers. not sure exactly what losi model they are from. half shafts are from a truck and will be shortened as necessary to match width.

rear arms are from slash or some kind of traxxas truck. they were spares from putting together a blue eagle, I ordered 2 diff part numbers and I think the arms are identical. they need to be shortened about 11mm, and redrilled, and slightly widened and clearanced for the losi hub carrier.

chassis and upper brace will be custom made, as will be the rear shock tower/wing mount.

battery trays are b44; top clamps and hardware will be custom made. the location of the packs will be adjustable with a series of holes for weight bias.

problems I have so far.....want to make the wheelbase adjustable, which means I have to modify the 4tec side plate, removing one of the motor mount screw bosses, so I'll have to replace a #4 or 3mm screw with a #2 screw becuase the molding gets thin. don't think it will be too much of an issue. once that is done, the arms will be able to be shifted 3 positions, nominal, and then shorter and longer by about 0.1"

rear suspension is fixed for toe and anti-squat. anti-squat looks good at around 1-2 degrees. I can add more by spacing up the front of the bulkhead if need be. toe is set by arms since the mounts are at 0 toe. The traxxas arms look to have about 3 degrees, so I'm just going to copy that when I move the outer hing pin location. this is the only part that i'm not happy about.

wheels are going to be yellow losi rears and some kind of buggy front to match, b4 or anything really.....i may switch to rulux wheels becuase i like 'em, and becuase they are available in yellow.

the last sticking point is going to be the body, but I think I'm going to end up with a AYK boost body, I think that will fit nicely due to the high spur gear location.

[jwscab]

BTW, the parts chosen for this were primarily cost driven.

all of the traxxas parts in the rear, from spur gear to output yokes was probably around $30.00. the gear diff was a brand new pull-off, with the side adjusters/bearings(important), the side plates are new; both from ebay. the upper shaft/pulleys/spur adapter/yokes were all from tower, as was the belt.

Ideally, I would have liked to used TC5 parts but all that machined aluminum is $$$, the nice part with that stuff is that the entire geometry is adjustable (toe, squat, height, etc). if I had no cars and was starting from scratch, this would have been my starting point.

the gear diff is also upgradeble to a ball diff, and traxxas has a slipper clutch for $16 bucks from tower in place of the spur adapter.

[Mr. ED]

maybe look around for a pair of bandit arms?
Getting the 3° in each shortened arm to be identical will be hell.

Good call on the 4-tec parts. I was doubting the transmission 'd be TF2 parts, but using those earlier I can tell you that gearbox was far from good.

Is the larger diff not sitting too low for chassis clearance?
Will you try flipping the moter over?

[jwscab]

the 3 degrees won't be that bad.....i'm using these because they are free at this point. i'm using a hinge pin as a setup guide in the chuck to set the arm position in a vise. Once I get that parallel with the drill chuck, it's a matter of moving the vise into position for a new hole. I have a decent machinist vice and I've drilled out some thinwall tubing pretty deep and it was still pretty accurate, so I have confidence in the setup. fortunately, the arms have a nice parallel surface to grab with the vise jaws.

the diff fits in perfect, but you need the eccentrics because the bearings are a different size.

i'm not flipping the motor because that will involve reverse rotation, or an idler, which I don't want to deal with. If the motor plate(it's molded) becomes an issue with durability, I may make an aluminum one, and add provisions for an idler and flip the assembly over.

[Toasted Coastie]

I love your logic, and am watching this one very close man. Go to it man!!!

[shane]

Very cool project.

[jwscab]

small but important update. Drilled the arms for the short hinge pin location. the arms needed to have a 11 mm reduction in length.

couple of pics showing the jigs and fixture and tools used. Nothing super exotic, easily reproducible.

first, set up a 1/8" rod in the drill press as an alignment fixture. then place the arm in position, so that it can be clamped.

I made up a small locating jig that can conveniently secured to the arm. this isn't always possible, but you can usually come up with something. with the jig in place, a pilot hole is drilled.

finally, a ream is used to get the desired hole in the arm. shown are all the pieces used to get here.

the final outcome. there are some slight misalignments that occurred, but in a positive way. the arm was not exactly plumb top to bottom, so I ended up with a slight anti-squat added, maybe 1/4 degree. For me, no big deal. Had I wanted perfect, I would have shimmed the vise with some paper on the low side.

the arms are almost exactly the same now, with about .005" total error, which translates to less than 0.5" error. after loosening up during use, the arms will have this much play anyway.

now the arms can be trimmed, some bracing will be removed that is in the way, and those stupid nubs will be taken off, I have no idea what they used them for, but....

I also plan drill hole so that the hingepins can be secured with screws, like the b4/b44 currently do. no eclips!

[THEYTOOKMYTHUMB]

If reversing the motor becomes desired here is a cheap option. It’s fairly long, but it looks like there might be space there. These motors are strong and last forever too. Looks like an awesome project.

http://cgi.ebay.com/Traxxas-Titan-550-Reverse-Rotation-Motor-E-MAXX-E-REVO-/360178280477?cmd=ViewItem&pt=Radio_Control_Parts_Accessories&hash=item53dc4c681d