My Midnight Deuce and a half...

[TOU]

I realize some of you may have read my various post about this in others threads but thought I would write it up in one place with some finished pictures. Anyway after coming across various U-tube videos and reading an article on prop Pinewood Derby cars, I knew that I had to just try to put something together this year for our Church's unlimited class Pinewood Derby. It has two classes that vary only by weight...a 5 oz & 8 oz class. Then I came across the threads by gpraceman & Nitro Dan and found a design that I thought would work well for my intent. Thx to their input I came up with a hybrid design.

gpraceman's Screaming Mimi
viewtopic.php?f=19&t=3257" target="_blank

Dan's 2009 Line-Up thread contained an design that I thought also might lend itself well for a prop rig:
viewtopic.php?f=19&t=4796" target="_blank

Well I put the finishing touches on the build phase of this rig...and it works...REALLY WELL! I will tell you first off is that the 5 oz weight limit is such a killer when trying to do something this extreme and still make it look clean. Heck, the batteries and motor weigh a ton by them selves. (Battery, motor, chip set, prop wires antenna, on-off switch weighs in at 3.5 oz...OUCH!) As did gpraceman, I used the park-flier plane that you can get from Harbor Freight for $29.99 on sale.



I then hollowed the motor's dowel a fair amount, ran razor wheels (On the front and back after the pictures were taken, skeletonized the skateboard in to a ladder frame as much as I dared. Admittedly I started out with one of the more dense pieces of pine BSA blocks though in order to maintain integrity...might have been a mistakes as it is a tad heavier. Live and learn and will probably do another down the road.

A couple of design changes that I had hoped to make over the Screaming Mimi was putting "On/Off" switch on the outside of the cargo box as to not have to access it once it's impounded. With covering it with model plane Monokote instead, in the end I found this not feasible this time and not necessary. I have tested it and once the batteries are fully charged, I can leave it switched on in a "stand by mode" for at least 48 hours and still have plenty of charge left.

I also wanted it to have the internals (battery) easily accessible. What I have come up with is that in the skeletonized ladder frame I then hollowed out truck cab and cargo box and glued them on. I used a Forsner (sp?) bit to for a 5/8 wood dowel for the the motor and prop to rest on. (This part is near identical to gpraceman's SM.) I then drilled holes out the back for the wires to go straight from the motor to the chip set inside the cargo box. (Necessitated cutting and re-splicing the wires inside though.) I took the antenna and had it go out the front and directly into one of the smoke stacks and out the top. (Obviously drilled for this purpose.) Next, I cut a thin balsa replacement panel that I just set in underneath after the battery has been charged, plugged in and added to the other "internals". To secure it, I figured since I couldn't find a way to to get it under 5 oz anyway (It's +6.0 oz.) I added an extra set of axes and wheels to make it look like a tandem axled truck...these are slightly raised. While they are functional...it is not in the way you'd think. Actually the wheels are strictly for looks...but the axles are functional. They act as part of a four point securing mechanism for this false panel underneath. I have to say though, since weight was no longer a factor, the second set of rear tires/axles look awesome. Additionally there is another set of BSA axles to complete the other half of the 4-point securing of this panel; they look cool also and look as though they are chrome rivets in the side of the frame further forward. (See picture below...finally gave me some kind of real use for stock BSA axes. LOL ) That all said...while the 4 extra axles are part of it's clean and functional design...they are extra weight as are the extra tires...but like I said, I gave up on the 5 oz maximum, no big deal.

As noted I chose to cover the entire thing with Monokote that model plane builders use rather than actual paint. I knew this would cost me some weight but was worth it for a few reasons.

• A) I figured balsa was a pain and time consuming to prep and paint anyway.
  B) Time was of the essence
  C) Stopping might be an issue and I wanted the added strength that it lends by binding the parts together
  D) Avoid Chipping on the paint...again on stopping.
  E) Look fairly decent from all but close inspection.
  F) ...not the best "paint job" but it worked for my needs this time.

I have to tell you though...this thing is going to be VERY fast! When testing the motors mounting on the car it just about ripped it out of my hand. It also blew papers off the counter...from FIVE feet away. It gets just about flying from a dead start on heavy thick carpet...even WITH the heavy wide BSA wheels! I think about the only thing that will give it competition is the possibility a couple of rumored C02 cars and one ducted fan car that may be show up. See what you think and I will keep you posted as to how it does this weekend.


Thx for Nitro Dan's & GPraceman's help!
TOU

[TOU]

Hey All,

I thought I would give you an update of this weekends festivities. We entered one car for each in my family including this one, seven total. Over all, we did quite well; I'll try to post them and their results in another thread shortly. Back to the Midnight Deuce & a half...

Results: Let's just say out of nearly 70 cars, nothing came close besides another prop rig that was running a much bigger motor, 9V but with 18V's of juice pushing it. We still beat it by an average speed of 15 MPH with our little 4.8V motor. . (There was a CO2 car but it was still working through its bugs.) BTW, we were running on 40' Freedom Aluminum track with a rubber stopping section. I knew the rubber would never stop my rig especially with the hollow bottom and the speed I was planning on running...so we took an extremely plushy fleece blanket for them to absorb their impact and not rebound them as foam might have. (Hopefully being able to last at least 4 runs...it turned out to be no worries in the end as it seems little worse for the wear.)

Heat 1: I just didn't know how the truck would fare so thought I would take it easy so that it would hold up through all four heats and any other exhibition heats. So, I waited until after the pin dropped and then hit the throttle and tried to let up near and before the finish line. There was a huge cheer as it flew down the track and I was just so surprised and elated that I was just laughing so hard I couldn't hardly talk. Even when I went back to my position at the start gate, I kept chuckling to myself. The thing that was amazing is that the other regular cars had barely crossed more than half way down the track when my truck crossed the finish line. It was just over 2.08 seconds and the fleece blanket worked GREAT to stop it...no damage. I knew it could do even better/faster though...next run. One thing is for sure it was definitely a huge hit and a real crowd pleaser through all the other heats!

The very next heat the other prop car ran his first heat. One thing about it, is it only had an off and on switch, so when he put it behind his pin, he would turn on the switch and it would run at full throttle while waiting for the pin to drop. (He never could find one of those switches for the front yet.) This meant that he instantly got the jump off the line as he was already at full bore. Obviously this also meant that he hit the blanket at full throttle and it was what stopped the prop until he could grab it and shut it off. (I think that he either bent or chipped his prop after one of his runs though...I chipped mine later running backwards up the track. ) He pulled a 1.999 sec so I knew I could...and would need to...change my strategy and technique on the subsequent runs if I was going to beat his average times.

Heat 2: Buzzzzzzzzzzz...I revved the motor to full throttle while at the pin before it dropped. The pin dropped and it instantly lept away and just about literally "flew" down the track. This time I kept it under full throttle until after it crossed the line as I knew the fleece blanket would do it's job well to stop it without damage. It pulled a 1.90?? something. COOOOOL! I had wanted it to pull a sub-two second car with scale speed of over 300 MPH...it did. Again I was laughing so hard and ecstatic about going even faster than the other car and got it to go sub two seconds.

Heat 3: The other prop car and mine were matched up on this same heat. I followed the same technique for this run as Heat-2. We won over the other prop car by two car lengths...WAHOO!!! Crowd was cheering like crazy for both cars. I was once again ecstatic. Don't remember this ones time except to say it was sub-2 seconds.

Heat 4: It was a repeat of Heat-2...and everyone was having a ball watching it and I still had my stupid grin going.


The fastest standard car of the day (a new car of my 14 year old daughter) had an average time of 3.0050 seconds and an average speed of 226.9 MPH . My Average time was 1.9473 seconds with an Average Speed of 350.1 MPH!!! The other Prop car's Average time was 2.0340 seconds with an Average Speed of 335.2 MPH!!!

Incidentally the other prop car must have been drawing so much juice from its two 9V batteries as after 4 heats it seemed to be slowing down a hair. Hence the other prop cars fastest run was his first, conversely my slowest run was my first run. Bottom line is it was a total kick and definitely something to get the crowd going and engaged.

Like gpraceman did, we (both prop owners) had planned on and went ahead and disqualified ourselves afterwords when we were announcing the results so the trophies and medals went to others...we already had our reward of satisfaction. We did take some video but I will have to figure out how to upload it at some point.

Hope you enjoyed sharing a bit of my excitement...definitely worth the effort and the little bit of money invested! I think this set up is the best bang for the buck & the easiest way to accomplish creating one of these exhibition type prop cars for such events...it by far exceeded my expectations. It also seemed that all in attendance enjoyed having it there. (Especially after we disqualified it from trophy contention and made it strictly an exhibition car.)

All the best!

TOU

P.S. Also as noted, the CO2 car made an appearance but was unproven and hence was struggling to stay on the track...it never finished a heat...hopefully next year.

Much of the kudos should go to gpraceman & Nitro Dan as they helped and inspired it's build...thank you!

[gpraceman]

TOU,

It turned out quite well.

Thanks for the detail on the races. Sounds like it was more flying than riding down the track.

[TOU]

Thx gpraceman, I appreciate that...as mentioned, I probably wouldn't have thought to use this kit with out your input and direction. They and their speed is quite addictive....I know they are not pure old school PWD but they are fun and the crowds and the little kids love'em. (Heck so do the "BIG" kids.) What I really liked is it shows what you can do with PWD with a bit of imagination and few added doallrs...I know it hooked several new converts the other night.

Reality is, I'm so pleased with it, that I'm thinking about taking the other spare motor and cowling's from the donor plane and making another one that is even better & with a more refined design...but under 5 oz for next time. (Still want to keep this one essentially intact and usable though as it's a pretty tough bugger.) I really want to make one based on the Tom Daniels Red Baron hot rod from the late sixties...we'll see. I'm thinking I will probably only need to put quick disconnect male/female connections on each of the motors wires and then just swap the chip set & battery pack back and forth between the two at will. (Of course, as you know, the chip set has both sets of wires attached anyway.) Thus I'll be able to run two rigs from the same radio and chip set...obviously just not at the same time. What a kick! I think you may have inspired a monster.

That said, we are not through building standard cars by any stretch though as I have two more cubs. As mentioned, we built several others for this race & my 14 year old daughter took 1st in the 5 oz (1st over all & Grand Champ), as well as 3rd in 5 oz. (5th over all), 2nd in 8 oz (3rd overall) the other three cars placed in the top 15 overall. The slowest but still fairly fast was an experimental non typical side railed "VanGough" type tricycle car that ended up with a vicious side to side speed wobble. I think I know how to correct it though. Anyway...it never ends, eh?!

Lots of fun!

TOU

[Nitro Dan]

TOU, great job on the rig! Now step it up a notch and install one of those wireless micro cameras on top the cab, then pipe it to an overhead projector so everyone can get a drivers point of view from a vehicle going that fast! I saw that someone had done this on a regular PWD car over in this thread:

viewtopic.php?t=3278&highlight=camera" target="_blank

-Nitro Dan

[Da Graphite Kid]

Tou,
You stated: "(I think that he either bent or chipped his prop after one of his runs though...I chipped mine later running backwards up the track. )"

Can you tell me how well the car ran up the track and where the starting point for it was? I don't have Cub aged boys anymore (them things grow bigger and older if you feed'em!) but still show up to the local Pack race and set up my track and run the PWD race for them. In past years I have built 'challenge' cars where I as the owner of the track could race against one of the Cub’s cars. Of course being the owner of the track I didn’t have to follow no stinkin rules! [The idea being here that the cars looked fast but ran like a block of wood without wheels and showed the cheaters just don’t win.] I was thinking about making a fan powered car yet have the motor reversible so that the car would get a bit down the track and than suddenly reverse direction and run back up the track. Having it jump from the starting gate would be a bonus and I’m sure a crowd pleaser!


Da Graphite Kid

[TOU]

Tou,
You stated: "(I think that he either bent or chipped his prop after one of his runs though...I chipped mine later running backwards up the track. )"

Can you tell me how well the car ran up the track and where the starting point for it was? I don't have Cub aged boys anymore (them things grow bigger and older if you feed'em!) but still show up to the local Pack race and set up my track and run the PWD race for them. In past years I have built 'challenge' cars where I as the owner of the track could race against one of the Cub’s cars. Of course being the owner of the track I didn’t have to follow no stinkin rules! [The idea being here that the cars looked fast but ran like a block of wood without wheels and showed the cheaters just don’t win.] I was thinking about making a fan powered car yet have the motor reversible so that the car would get a bit down the track and than suddenly reverse direction and run back up the track. Having it jump from the starting gate would be a bonus and I’m sure a crowd pleaser!


Da Graphite Kid

Sorry for being MIA for so long...when I say backward, I just turned it around and sent it back up the track. I chipped my prop when I had a friend that was supposed to be catching it (It was like Evil Knievel jumping the Grand Canyon) but didn't do a very good job catching it.

Trust me when I say the up hill slope was no big deal for it! It was almost as fast going up as coming down. As to reversing the direction of the motor in mid-stride...mine is not set up that way; additionally props are generally uni-directional. Hope this helps.

BTW, I have used it as a exhibition car a couple of times since with great reviews...kids and adults just LOVE it. It doesn't hurt that I am pulling sub 2 second runs and it hits the finish line about the same time the fastest cars are at the midway point. LOL

[TOU]

TOU, great job on the rig! Now step it up a notch and install one of those wireless micro cameras on top the cab, then pipe it to an overhead projector so everyone can get a drivers point of view from a vehicle going that fast! I saw that someone had done this on a regular PWD car over in this thread:

viewtopic.php?t=3278&highlight=camera" target="_blank

-Nitro Dan

I've been looking into this...maybe if I can get the funds and time. Working on my sons cub car for next weeks cub race. Procrastination...and time are my enemies. Probably can't get it done for pack races but maybe for districts if they will allow an exhibition run or two...that would be fun, but they are such stick in the muds about such stuff. They forget it is not about just running races but is for the kids and their imaginations.

[Kenny]

Fun post. I have some LiPo batteries and 400 brushless motor/ ESC with a micro receiver in the drawer from an old retired flying wing. I just may put something together as well after reading your post.

In fact, my receiver has a few unused channels so might be able to get creative with one or two micro servos and some LEDs

One thought does occur to me and that is that these little suckers can crank out some rpms and that prop will take a finger pretty quick if it gets away from ya, so keeping the kids at a safe distance during demos is probably a good thing...

Thanks for sharing! Sounds like good fun.

K

[TOU]

I hear you, safety is key, it is mostly something that "Dad" runs. Keep in mind the prop stops as soon as I left off the throttle. It is also say now that we run it in to a "buffer".

When I first ran it I was unsure how to run it and how much abuse it would put up with. So I initially waited for the peg (starting gate) to drop, then I would hit the throttle. That was okay in general but then there was a guy that only had a on/off switch that was running full throttle before the peg dropped and then it ran full all the way through the finish line. I still beat him (barely) but it was really dependent on my reaction times and the fact that I still had to throttle it up after he was gone. (maybe .25 s or so)...I had to play catch up. Once I realized how strong the set up was especially with the mono-cote covering I changed my MO. Where I had been also letting off the throttle when it got near the finish line, I now run it full throttle all the way through.

What I did to be able to run it it full throttle the entire time, was put a really plushy fleece blanket very loosely at the end of the track as a "buffer". I then just run it flat out right into the plushy fleece blanket which brakes it nicely...with out breaking it. Works perfectly and allows me to eek a bit faster times with no harm to the truck. (With out it, it would shoot over the braking segment with out question...especially since it is essentially hollow underneath and is quite slick. Also in order to beat the previously mentioned prop car as well as a CO2 car e were racing, I also started running it at full throttle a second before the pegs dropped. Now I always run high 1.8's and mid 1.9's...especially with additional nickel axles and razor wheels. Kinda silly...a bit costly but a ton of fun for all!