warren528

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Hi all,
Here are a few photos of my WCM 1/4 scale Nascar modified to a Drag Car. I'm planing on DRAG RACING this car in a OUTLAW class in 2008.

Thanks Warren528[:@]

M.R. Ogle

Looks cool...

People try to drag race 1//4 scale NASCARs where the rear axle is driven off a pulley offset way to the side, like right next to the rear tire... those cars usually have a hard time running straight under hard acceleration.

Yours, fortunately, has the rear pulley centered, so it'll probably work just fine!

ahr43

Interesting input Mike. Kinda wondered about that myself for 1/10scale. I'll be building a new rear clip for my TFE (Top Fuel Electric) car. I'm thinking I'll build my pulley drive off your centerline recommendation.

But I am curious why single reduction electric cars don't suffer from a pull to one side, with the pinion/spur being located far right drive? Perhaps you could provide addl info as to why it effects a pulley drive double reduction car and not a single reduction car?

Oh!, and yeah warren...nice looking Qscale car. Welcome to the crazy and wild world of RC drag racing. Good luck. Sure you'll do well.

AC

M.R. Ogle

Here's my observation.

From what I've seen, the quarter-scale cars that have a working rear suspension and are driven off an offset pulley get "bound" on that side by the pull of the drive belt, especially when the car gets "on the pipe"...it "pulls" on that side of the axle, and binds up that rear wheel's up and down suspension movement more than the other rear wheel. You don't really notice it on an oval car, which are heavily offset in many ways anyway, but when trying to run hard in a straight line, it certainly shows up as one rear tire having more "bite" than the other, and the cars do a "flat spin" about 75 to 80 feet out.... seen it many, many times...

The solid rear axle electric or nitro drag cars with no suspension to bind up would not be affected in this way.

warren528

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M.R. Ogle,
Thanks for all the great infor. you have provided on this 1/4 scale chassic setup.

Warren528[sm=thumbs_up.gif]

annie_himself

Where do you plan to race this? And where did you race oval 1/4th scale?

ahr43

Thanks M.R.O. The above info is very useful.

I have noticed that my axle and wheel bearings have a lot of axial movement-even when new. Actually, too much clearance b/w the race and balls to my liking. Short of going to ceramic bearings (!$!), do you have a source for a "tighter" RR axle and FR wheel bearing set(s)? Like maybe a 'mil spec' source or even stainless steel source? The 'hobby' or 'industrial' grade I am getting leave my worring about load failure at the rear. I did "double-up" from two (2) to four (4) axle bearings on the R2E-2 for TFE next year. Or maybe it's not to worry about?

AC

M.R. Ogle

Hey, I'm on here...

The way I see it, with all that squishy drag foam on the tires, if there's any "play" in the rear drivetrain, THAT's where it will show up.. or get soaked up... a small amount of rear axle movement probably doesn't do anything disturbing in transferring power to the ground. The only possible detriment would be if the movement was severe enough to disturb your gear mesh, which it certainly isn't... and those molded nylon spur gears usually have a thou or two of squish to them, too... along with the bearing in the motor can.

Besides, if there was excessive play in the bearing, as soon as you hit the throttle, the spur gear would try it's best to divorce itself from the pinion, and slam the rear axle backwards in the bearing, probably holding it there until you got off the throttle.

I've not seen that ceramic bearings are a noticeable improvement in anything, except where heat is a factor, like in a nitro motor's crankcase.

M.R. Ogle

One more thing... I don't think "load failure" is an issue with our cars... we took Cliff Lett's 5+ pound car at 111 mph around a bumpy REAL race course in California (Irwindale Speedway), and around concrete bicycle velodromes... with those same bearings we're using in GMS kits now... if anything was going to blow out a bearing, it would be the lateral forces seen in that type of load application, not what we're doing with them.... no worries.


The only time I'vve seen a rear bearing failure in a drag car that was not caused by an accident was when a mocroswitch-equipped 45 ounce 20-cell car went into full rear wheel lockup and bounced through shutdown... hmmmm... that'll pop a bearing.

rc10johnny

Hi! I just traded for 2 chassis OLD......LIKE ME!!!!! do you know where to get some tires or bodies,one car has a rusty wallace body the other must have been a sprint (small front bumper) THANKS JohnnySr johnboyryan2@verizon