dragnse7en

LOL

Just reverse the thing I said, and it will make much more sense than you think. TRF417s, X Ray 2011s, and Hot Bodies ues ll the same design.
Use the ball on the axis, not on the pivot point!!!!

depro

Hmm I'm not sure if we're thinking about the same idea for the ball link, but its ok. I'm just gonna stick to traditional hinge pins to keep it simple.

Does anybody have suggestions for gearing it for a track? I know it depends on how tight the track is and such, but any general ballpark idea would be nice.

dragnse7en

A Two to One gear ratio is the biggest thing today, even w/ the BL motor systems.

ozzie-crawl

quick explanation

engineers = make a simple job complicated or imposable

fabricators = makes the imposable possible, fixes engineers f***ups

Haddi Taha

man I can't find nylon sheets locally.

dragnse7en

Would polystyrene sheets work as a good substitute? I know where to get tons of sheets of that.

depro

Haha but I think engineers get paid more. Not sure how that works. As for plastic, here's a really nice comparison table.

http://www.machinist-materials.com/c...r_plastics.htm

That's how I concluded that nylon would be the best plastic. I could only find it online. The best place is http://www.mcmaster.com/

Haddi Taha

what type of nylon? Nylon 6/6?

depro

Yup Nylon 6/6 is exactly what I got. I use the 3/8th's thick sheet because it gives you that extra thickness when drilling holes vertically into it. Plus you can also dye it almost any color you want by boiling it in fabric dye (which is really cheap and easy to get).

I was meandering around Mcmaster's website today and I discovered that gpo3 and g-10 fr4 sheets are really cheap. Gpo3 is definitely the cheaper one at $12.40 for a 1/8x12x24 sheet. The same size G-10 fr4 sheet costs $25.10.

So in the interest of saving weight and working with new materials, I think I'm gonna scrap the aluminum chassis. I'm leaning toward the Gpo3 simply because its cheaper.

I found out somebody else discovered gpo3 before me: http://i483.photobucket.com/albums/r...x/DSCN2419.jpg

Here's the gpo3 on Mcmaster: http://www.mcmaster.com/#fiberglass-...erials/=d7j0kp

And here's the G-10 Fr4 on Mcmaster: http://www.mcmaster.com/#grade-g-10/...rolite/=d7iu3s

Haddi Taha

do they ship world wide

depro

Doh it looks like they don't ship worldwide...

depro

I've been really busy these past few days because the summer semester is wrapping up and then I'll be out of town for a couple weeks. I did however take a few shots today of the offroad truck I built. Enjoy.

Haddi Taha

wow, you did a good job with it

depro

Thank you. Its definitely a blast to drive. As for the onroad car, I've decided to move around the components a bit for better weight distribution. I'm gonna basically reverse all the components and have the motor towards the front rather than in the back. I calculated that this would give me an almost perfect 50/50 weight distribution. With the motor in the back as previously planned it would have had way too much weight in the back.

Haddi Taha

keep in mind where the other electrics are and that the weight shifts forward under deacceleration

depro

Yes that's true. I suppose I might be posting in the wrong forum if I say I'm now creating a drift car, so I'll say I'm trying to make the best of both types of onroad cars with the 50/50 weight distribution. Here's a rough Autocad sketch of the new chassis configuration. The front is on the right.

Haddi Taha

Looks great. Might be a bit front heavy for grip racing.

dragnse7en

I was thinking more of a torque-steer issue with the motor's output shaft positioned so far forward

Haddi Taha

I think its better to have the motor in the rear, like most of the onroad shaft drives. I've only seen drift cars like the tb03vds and e10 have motors in the front.

dragnse7en

If the motor stays in that position, but flipped to the other side of the chassis and flipped again so that the output shaft faces towards the rear of the car, he'll greatly reduce the torque-steer issue, but he won't be able to get rid of it completely.

depro

Wow in all my research I've never come across the torque steer issue, thanks very much for the heads up. Can anybody post a link to a really comprehensive article that explains the issue and how to possibly get rid of it or how to design to minimize it? I'm all for moving the motor to the back again if you guys think torque steer is gonna be a big issue. Can somebody also explain why its better to have more weight in the rear for grip racing? Thanks for all your help!

By the way what if I attached a counterbalance to the center drive shaft to effectively cancel out the two rotational torques?

dragnse7en

Here's a quick link: en.wikipedia.org/wiki/Torque_steering

Basically, it means that the torque of the motor/ tranny is overcoming the traction of the front tires. The torque breaks the tires' grip, and pushes the car in the direction the torque want to go. Although it's a big issue on older full-size front wheel drive cars, it happens to rwd and 4wd as well.

To kill torque-steer on rc cars, they throw the motor in the back, so that there's more traction and it isn't overpowered by the torque. Mounting the motor sideways and usiing a crown/ bevel gear after the spur and pinion to drive the mainshafts would help too.

dragnse7en

I really can't post my engineering handbook on the web b/c I have no scanner. There should be a web reference somewhere though for an enginner's handbook. Go to the index and look up torque.

Haddi Taha

Its better to have the car slightly rear heavy because you get more traction in the rear. Putting more weight in the front wheel give the front more traction causing the car to over steer. If your car is too rear heavy that will cause some problems too (The car will understeer and steering feels strange) . Just look up some pictures of shaft driven touring cars to see what to aim for.

Haddi Taha

Updates?