Did I make a big mistake

[Prozach2]

This is my first post, so hello everyone! Now, here's my dilemma:

My son's first pinewood derby is tomorrow, and I think I made a big mistake. The car has been turned in. It's too late to make any changes. We're new to cub scouts, so I didn't have much time to build a car. Only a few days. We read the local rules, read what we could on the internet, and bought a bunch of stuff from the Scout shop. Here's what we came up with:
- Our car is a very thin wedge; a 1/4" at the back.
- We extended the wheel base.
- We've got the vast majority of the weight in the back. There's a 3 oz tungsten disc directly in front of the rear axles and more than an oz behind the axles. The COM is a little more than 3/4" in front of the rear axle.
- It has three standard BSA wheels and three straight polished BSA axles. There are two wheels in the back and one in the front on the left. There's no right front wheel.
- The wheels are not canted and we did virtually no tuning. I did a couple of test runs on the floor, and it consistently goes a little to the right.
- It's loaded up on graphite.

With such a slim car, all that weight in the back, and virtually no tuning, this car is probably going to bounce around like crazy. With no front wheel, it's going to go flying off the track isn't it??

There's nothing I can do to change the car at this point. Do you experience racers agree with my concern? Do I need to be preparing my 9 year old for the reality that his car that we worked so hard on might not even make it down the track?

 

[TRE]

I dont think it will stay on the track with out a guide pin or a wheel there

 

[ironband]

Even the pros use a guide pin when they omit a wheel.

It's really hard to say what it will do. You might get lucky, but probably not. With the race tomorrow, hope for the best and prepare for the worst. Remind your son that sometimes in striving for greatness we fail spectacularly. Have fun and remember that a lot of folks go to races for the wrecks. It's probably going to be rough, but do your best to keep your mood light and hopefully your son will follow.

Good luck one way or another!

 

[Prozach2]

Even the pros use a guide pin when they omit a wheel.

It's really hard to say what it will do. You might get lucky, but probably not. With the race tomorrow, hope for the best and prepare for the worst. Remind your son that sometimes in striving for greatness we fail spectacularly. Have fun and remember that a lot of folks go to races for the wrecks. It's probably going to be rough, but do your best to keep your mood light and hopefully your son will follow.

Good luck one way or another!

Thanks guys
The cars weren’t due until today at 6:00 PM, so I’ve sent an email requesting permission to fix it. If allowed I plan on putting the wheel back on, which was originally raised and tight, and then drilling hole(s) in the car until it makes weight.

 

[Prozach2]

I’ve been given permission to check the car out and check it back in. I’ll let you guys know how it goes. Please let me know if there are any tips on trimming down the weight of the car after adding the wheel back. I have a large drill bit designed to make a hole for the three oz tungsten disc. Due to the high COM and lack of tuning, I thought it would be wise to put the hole right in front of the tungsten disc which is directly in front of the back axle. Hopefully, this will avoid moving the COM back too much more and minimize fish tailing.

 

[Thinkin'Bout Racin]

I am not a pro, so take this with a grain of salt ...if you have a scale, then take a block of wood tonight and drill some holes in it. Save the shavings and weigh them. Your extra wheel and axle will weigh about 2.6-2.7 grams. That way, you know about how much material you will need to remove. Look at the hole/holes you drilled and make a plan of action on how to remove weight from the car.

Planning to add the front wheel back on is a GOOD idea!

Best of luck!

 

[AceMontana]

Although its not what you described exactly heres a pic of my very first three wheeler and it has a 1/2" COM and no guide pin 2" of drift in 4' stays on my wooden test track just fine....so although i cant say if your car will stay on or fly off i know its possible without a guidepin....not the safe thing to do but ive done it.

 

[TRE]

It will stay on the track with enough steer

 

[HurriCrane Racing]

good thing you were able to get the car out of the impound. I'm fairly certain the car would have had problems and maybe took out another scout's car in the process.

I've only heard of a racer called JB07 that ran without a guide pin or third wheel.

good luck!

 

[Prozach2]

Thanks guys! I’ll let you know how it goes. Here’s the final product. Notice, we’ve sanded off most of the paint to make weight.

Please let me know if you have any last minute suggestions or advice. I have about 3 hours before start time.

 

[HurriCrane Racing]

Make sure you cover any drill holes or cavities in the car with vinyl or packaging tape.

Good luck!

 

[Thinkin'Bout Racin]

Make sure to clean the wheels before racing.

 

[Loud2ns]

I did it once......3 yrs ago..... didn't go well. They were fast, but wild. I'm pretty sure my boys yellow minion car tripped the lane next to him and tripped his with his rear end. Lol. Wheel or guide pin!

 

[Prozach2]

Make sure you cover any drill holes or cavities in the car with vinyl or packaging tape.

Good luck!

Thanks! I’ll definitely do that.

 

[Prozach2]

Make sure to clean the wheels before racing.

I was going to dump a ton of graphite on the front and back of hole, spin the wheels for about a minute with my finger, then wipe them clean with cotton balls and rubbing alcohol. Is that right?

 

[Charles Studer]

Good luck!

 

[Prozach2]

We won first place! I doubt we would’ve even finished without your help. Thank you so much!!

HurriCrane, the bottom of our car looked pretty jagged after drilling enough holes to make weight. I think the packaging tape tip helped a lot.

 

[Thinkin'Bout Racin]

We won first place! I doubt we would’ve even finished without your help. Thank you so much!!

HurriCrane, the bottom of our car looked pretty jagged after drilling enough holes to make weight. I think the packaging tape tip helped a lot.

Congratulations! Hard work, a few missteps, more hard work all paid off! You made some great memories with your boy that will last a lifetime for the both of you. I for one am glad you came here and recognized the possible problem and asked for help. Lots of great people here to help out!