Derby Talk

In this thread, http://derbytalk.com/viewtopic.php?t=3256, I went into the results for our Cub Scout race, which was yesterday. I didn't want to steal the thunder in that thread from my two sons, since they did quite well at the race.

Well, here's the story about my car. For the Open Division, the rules were basically that it must fit the track, not interfere with other cars, not have anything hazardous (like mercury), but still be no more than 5oz (got to make it a challenge). Last year I used razor wheels and needle axles with my "Wind Tunnel" car (http://derbytalk.com/viewtopic.php?t=2074) to win the open division.

For this year, I drew inspiration from Randy Davis' prop cars. Last year, I bought a RC airplane from Harbor Freight, for all of $29.99, and got some good flying out of it. We also got a few good crashes (broke a wing and a major crack in the fuselage from a nose dive). I figured that I'd give that plane a second life as a Pinewood Derby car.

Here's what I started with:


So, I gutted the electronics, cut up the plastic engine mounts to use with the car. With the motor and the battery pack (essentially 4 AA batteries), it was going to be a challenge to make the 5oz limit. I had to use a lot of balsa and ordered some razor wheels from MaxV to save on weight. The only pine in the car is a thin sliver of the base, but even much of that was replaced with balsa.

So, here's what I ended up with. I call it the "Screaming Mimi":



One of the dents you see on the nose was from a test run on my floor. The car hit a door jamb, so I made a matching dent on the other side to make it a part of the design.

Results: It blew the competition away. Pun intended. Literally so, in one heat (keep reading).

Heat 1: As soon as the cars were released, I hit the throttle on the remote control. Zoom... Then I cut power as it crossed the finish. Up to that point of the race, the fastest time was 3.032 secs (208.0 scale mph) on a 40 ft Piantedosi aluminum track. It came in at 1.999 secs, 315.5 mph. There were high five's all around.

Heat 2: Zoom... This time it was 1.957 secs, 322.3 mph, its fastest run.

Heat 3: This one was going to be interesting. It was in the lane next to the bird car (complete with ostrich feathers). Zoom... Feathers go flying! Guys were joking about a bird strike. Fortunately, the damage wasn't that bad to the bird car.

Heat 4: Matched up against Evan's "Always on Time" car. What I didn't know was that while Evan was helping pre-stage the cars, he opened the hatch to my car and turned off the switch to the battery. You can see the switch in one of the photos above. So, the gate drops and I'm trying to hit the throttle, but nothing is happening!?! Laughs all around. Guess what...It still beat his car and won the heat. A fact which I had to rub in with Evan.

I disqualified myself afterwards, when we were announcing the results. So, Evan ended up with the official "bragging rights" for the open division. I was just doing it for the fun of it.

I wish I had it all on video. I even brought a video camera, but forgot all about it.

Here's a picture of the bird car from Heat 3.

That's cool, wish you would have had the video running too.

CM924 wrote:That's cool, wish you would have had the video running too.

I'm glad you like it. The race was a real hoot.

I'll probably have to run it again at one of the races that our pack does for other packs, so I can get it on video.

I think next time I drop in on Randy Davis, in Arizona, I'll have to challenge him to a prop car race!

That's hilarious!!! Nicely done.

PWD_addict wrote:That's hilarious!!! Nicely done.

Thanks!

If anyone else builds a prop car, the RC route is definitely the way to go. With MaxV's prop cars and some of the others he shows, they had to manually be turned off at the finish. I liked that I could kill it and not risk damaging the car or any other car. That and no one had to try to grab the thing while running to kill the motor.

The 5 oz limit was a big challenge, but fortunately, with balsa and the lighter wheels I was able to squeek in right at 5.00 ounces.

For $29.99, that plane was well worth the flight time (in the air and on the track).

I love it!!! I can't wait for my sons RC helicopter to break, Umm I mean... It will be a shame when his toy breaks and I rescue it from the trash!

gpraceman wrote:...If anyone else builds a prop car, the RC route is definitely the way to go. With MaxV's prop cars and some of the others he shows, they had to manually be turned off at the finish. I liked that I could kill it and not risk damaging the car or any other car. That and no one had to try to grab the thing while running to kill the motor.

The 5 oz limit was a big challenge, but fortunately, with balsa and the lighter wheels I was able to squeek in right at 5.00 ounces.

For $29.99, that plane was well worth the flight time (in the air and on the track).

Very nice job, Randy!

We did a prop version before, but without the RC and with a motor that just wasn't fast enough and with regular instead of razor wheels.

If we do another one, we'll have to include your "upgrades".

Bubba

p.s. Had our races yesterday, GPRM v7.0 worked like a champ. Big kudos.

A balsa wood airplace that has a wind up prop and Rubber band might do the trick if the Gate Master is cool with dropping the gate a second or 2 after you let go.

For Adults I don't see why not

I have at least one completely destroyed Storm Launcher in my sons room - thats two props and all the electronics. My question is - what is the total height of your car?

chesspupil wrote:A balsa wood airplace that has a wind up prop and Rubber band might do the trick if the Gate Master is cool with dropping the gate a second or 2 after you let go.

RC is so much more fun! Plus these motors put out a lot more thrust.

pack529holycross wrote:I have at least one completely destroyed Storm Launcher in my sons room - thats two props and all the electronics. My question is - what is the total height of your car?

We have a 5" height limit and it is right at that (to tip of prop). I could have made it maybe 3/4" shorter, but I think having the prop higher gives it more thrust (airflow to the prop being less obstructed by the body).

That plane is still available in the HF flyer I got in the mail yesterday!!

Pinewood Daddy wrote:That plane is still available in the HF flyer I got in the mail yesterday!!

Yep and it goes on sale quite often.

I was more than a bit skeptical as to how it would fly for being so inexpensive (and from HF), but with some little trim adjustments to the tail, it flew pretty good. Just fly it on a very calm day and launch it only slightly nose up (too much nose up can lead to a nose dive). Packaging tape works real good to patch a broken wing.

If you fly it down the track as a PWD car, just make sure there are no bird cars around.

I figured for $29, I wasn't wasting too much money if it didn't work out. It turned out to be well worth the small investment.

gpraceman wrote:

Pinewood Daddy wrote:That plane is still available in the HF flyer I got in the mail yesterday!!

Yep and it goes on sale quite often.

I'll keep an eye out for it.

Hit me with a reply if you see it...

Bubba

Go Bubba Go wrote:

gpraceman wrote:Yep and it goes on sale quite often.

I'll keep an eye out for it.

Hit me with a reply if you see it...

It is on sale right now on their website.

http://www.harborfreight.com/cpi/ctaf/d ... mber=92304

Print that out and take it to the store. They will honor the web price.

gpraceman wrote:Print that out and take it to the store. They will honor the web price.

Guess where I'll be going at Lunch today?

Thanks Randy.

Bubba