Riley and I recently visited the Franklin Institute with Pack 32 as part of a "camp-in" event.  We packed our sleeping bags and camping mattresses, and rolled up to the Franklin, ready for some science.

We arrived quite a bit early so that we could have dinner outside of the museum.  We took an Uber to a ramen place I know, since Riley loves ramen.  We both had a bowl of utterly unreal ramen -- There's nothing like real ramen, not the dried kind you get in the little orange bags.  We both opted for the hard boiled egg. It was super tasty.

After dealing with some taxi weirdness getting back to the Franklin (the Uber we requested got pulled over by the cops on the way to pick us up!), we met up with some scouts near the big statue of Ben Franklin, and headed with our gear to our "camp site" in the Earth Science exhibit.

In the camp-in, each group is assigned an exhibit in the museum in which they make camp.  You simply spread out your bag on the floor and you're set up.  No tents!  The Earth Science exhibit we were in talked all about global warming, earthquakes, and erosion.  We camped down in the erosion section, which had a padded rubber floor since there was a water trough.  It was the only padded floor I saw anywhere in the museum, so we had a good pick!

After we were set up, we went to a presentation about sports science, where a scientist gave some demonstrations about why warming up is important and how it affects your body if you don't warm up before doing sports.  Several of the scouts in Riley's den assisted the show.

After the show, we headed to the observatory, where we got to look through the big telescopes on the roof of the museum.  This is a special treat since you can't ordinarily use the telescopes during the museum's open hours (since it's daylight).  Unfortunately, there was a lot of light pollution, and only a few stars were visible.  It's almost a shame to have these big telescopes in a location that has such poor visibility.  Nonetheless, it was neat to be able to look through them.

We spent some time in the sports science exhibit.  Many of the other scouts were interested in the sports exhibit, and that's it.  I think that our scouts do not get as much exposure to awesome science as Riley, because he quickly (in comparison) became bored of trying to run faster or jump higher than everyone else over and over, and wanted to see other exhibits.  So from here, we parted with the rest of the pack to check out some of the other cool exhibits in the museum.

We spent a lot of time in Ben's Lab, where there were physics experiments and optical illusions.  That is always a fun place in the museum.  We played with some experiments with light, which were really neat.

It was then time to re-join the pack for our planetarium show.  I think at some point while we were in Ben's Lab, the rest of the pack decided to order in pizza, but we were ok since we'd already had ramen.  But as a result, the rest of the pack showed up just before the show started and got different seats, whereas Riley and I got to lay down dead-center, which was pretty cool.  The show was narrated by Neil Degrasse Tyson, although I can't even tell you now what it was about.  Some pretty generic space content, is what I suspect.

After the planetarium, we all had to head to bed.  We were worried that some of the lights on the displays wouldn't be off, but they were all eventually turned off by some custodians.  The floor was not too uncomfortable, but some of the other scout dads snore pretty loudly, and it was hard to stay asleep.  One of the other scouts was sleeping opposite me from Riley and kept rolling over and slapping me all night.  He also kept asking me where the bathroom was when I was trying to sleep.  This made me irritable at night, and groggy in the morning.

When we got up, we headed to breakfast in the cafeteria.  There was cereal and muffins and fruit and coffee.  We ate a bit and then went to the new Brain exhibit that the Franklin has.  The Brain exhibit was pretty neat, and the experiments there were all interesting.  I think this was Riley and my favorite exhibit of the weekend.

After we were done with the exhibits, Riley and I stopped by the gift shop to look around. I bought a Franklin sweatshirt and Riley got a glass prism.

In the end, it was a fun trip, and something I've always wanted to do has now been crossed off my list.

Last Saturday, Riley and I took our car to compete at Cub Pack 32's pinewood derby race, placing 2nd among the 33 racers submitting cars.

The Design

Last year's car didn't make it out of the shaping phase.  We got the car down to the shape and added weight, but I forgot to weigh it with the wheels.  When I tried to take some wood out of the center with a rotary saw, it went haywire, taking out way too much wood, extremely weakening the car frame, and still coming out overweight.  We had to bow out of the race.  But not this year.

We started concept work on the car months ago, beginning with me asking Riley what theme we should strive for this year.  His vehicles are all named after animals that are not typically known for their fast movement. The Penguin might go fast in the water, but it certainly doesn't through the air of a rocket derby. The Turtle is well known for its slow movement. October's rocket derby featured Riley's Skunk, which took first place.  This year's theme?  The Squid.

We looked online for some squid designs for inspiration, and found a few good ones.  We settled on one and I drew up some mock-ups.  Riley liked what we came up with, so we pressed forward.

I'm both surprised and not surprised that nobody asked about the process we used to paint the car.  All of the cars were styled differently, and Riley's was certainly done with a different technique from the rest.

After the car was sealed and primed (which Riley helped with), I transferred the squid design using tracing paper onto the primer coat.  I then painted the "water" area with frisket, which is a rubber cement-like substance that covers an area that you don't want to paint, then peels off later.  With the frisket dry, Riley used an air brush to paint the squid.  The use of the airbrush gave the car a fantastic flat paint quality that a regular brush couldn't come close to.  There were some other cars that obviously used spraypaint, but didn't include the frisket for detail.  Anyway, I'm happy with how that turned out.

I intended to use the frisket again to cover the squid parts and allow Riley to airbrush the water blue, but I was afraid the frisket would take off the squid-colored paint, since we didn't have a lot of time to let it cure to the primer.  So instead, I hand-painted the water with some dry-brushed black "seaweed" at the front of the car.  This even had the effect of making the blue water look watery, which was a cool side-effect.  Overall, I think the car looked great.

The Engineering

The pinewood derby is a hot contest among some scout dads who go into the race for the competition.  Some people complain that it becomes a contest between dads, rather than a fun activity for the scouts.  I wanted it to be as much of a learning experience for Riley as possible, but it's simply impractical for him to use a band saw at age 9.  So I involved him as much as I could, and made sure he understood the science behind the things I was doing to the car, even if he wasn't doing those things directly.

There were many things we did to make the car go fast.  I cut the wood block thinly, with a narrow, "aerodynamic" front, and space in the back for weights.  We drilled the axle holes with a tool that guaranteed straight axles, and lifted one wheel entirely from the track to reduce friction.  I drilled out holes for the weights in the back of the car, so that the weight could stay on the down-slope for as long as possible to give the car that extra "push".  We put slightly more than the allowed 5 ounces of weight in the car with weighted putty, so that we could slowly remove the extra weight and hit the 5 ounce limit from above, rather than trying to raise the weight from below.  The wheels were selected for consistent spin and balance from a large set, then the bores were polished.  The axles were polished with increasingly finer sandpaper until they were absent of visible scratches under a magnifying glass.  The axles were ever-so-slightly bent to allow them to be aligned in a particular way.  The alignment of the car was tested and re-tested to go not completely straight, but to allow the three-wheeled car to effectively track the rail while racing.

And that's just the stuff off the top of my head.

Riley helped with many of these things, and watched the things that were not safe for him to do (or he was too nervous about to handle himself).  I was particularly proud of him polishing the axles after I told him it was one of the most important parts.  He took to the tedious process and did a great job.

Overall, I think you can ask Riley about any aspect of the car, and he'll at least know why we did it, if not having had a hand in it himself.  I think this combined with having the chance for us to work on a project together are the most important parts of the derby, and I think we did alright.

The Race

I volunteered to chair the race committee in 2015, so I wanted to be involved in the race this year to know how everything was set up.  Our pack has a good track record of smooth events, so I feel getting knowledge passed on from a predecessor is an important part of keeping things running smoothly.  As such, I showed up early on the day of registration to help set up the race area, the track and electronics, and registration itself.

Our track races four cars at once and uses an electronic timer to detect race starts and finishing places.  This is all hooked to a computer with software to schedule races, monitor the race outcomes, and produce the result reports.

On the day of the race, I volunteered to place the cars on the track and release the gate to start the race.  This was a lot of fun, but also a bit nerve-wracking, since setting a car on the track at the wrong angle could cause it to lose, and many cars were balanced very weirdly, making them harder to place on the track than you might think.  Really, it's a complex job!

The downside of this position is that I could not easily watch the races.  There is a mechanism in the release that resets the timer in the electronics, and it was too much of a temptation to reset the release right after the cars crossed the finish line, rather than waiting the appropriate amount of time so that the results could be seen and recorded.  The end result is that I didn't actually watch many of the races.  In fact, I did watch the very first race (which had Riley's car in it), and I screwed it up, which led me not to watch any of the other races.

That said, from what I heard and what little I did see myself, Riley's car did very well.  His average speed on our track was around 233.7 MPH, scaled to the size of real cars.  As far as I know, this average speed was faster than anything else on the track.  In many of Riley's races, his car seemed to pull away from the other cars on the flat, which seems to defy a car's capabilities.  Really, this is all about weight placement and center of gravity, something that Riley and I spent a lot of time talking about and working on.

The races were broken into 3 sets of heats.  The first set was all 33 cars racing against each other.  These races determined winners within each den.  The second set was a semi-final, racing the top 16 cars to obtain the top 4 finishers for the pack results.  We ended up with some ties in that second set, so our final set of races had 6 racers.

Riley took first place in his den during the initial heats, which earned him a medal.  My dad took video of some of these races.  His car placed first in the semi-final, moving on to the final race.  In the final set of races, he won the first race, but came in second place for the next two.  This was fairly disappointing, considering his consistent first place finishes in all the other races.

Later, we found that the axle locks (small hex screws we used on the bottom of the car to hold the axles in and at a specific position) on three of the wheels had been ripped out of the bottom of the car.  The end of the track has some rubber ramps to keep the cars from shooting off the end, and these probably caused the damage.  When we handled the wheels, at least one of the axles was very loose, sliding in and out with very little effort.  It's surprising that the car did as well as it did in this condition, and I can only assume that had the axle locks held up, Riley would have passed the first place car, just as it had on every prior race in which they had been matched.

Still, second place is a great showing, and the races at the end were all very, very close.  In fact, the race data shows that Riley's car and the winning car had the exact same average speed in the final set of races, down to the tenths of a MPH.  It just nosed out the Squid in those last two races, putting him ahead.  Good job, Christopher.

There was also a people's choice award, where the scouts vote for their favorite car design.  In previous years, only the top car would receive an award.  This year, we did first through third place medals, which I think is a great idea, considering how much time scouts and their parents spend on these cars.  Riley's friend, Colin, won second place with his classic Batmobile-like car, which was shaped out of the wood block with a Dremel tool.  Pretty cool.

Placing in the top three in our pack means that we get to advance to the district race.  This year, the Horseshoe Trail District pinewood derby race will be May 10th at the Exton Mall.  I'm excited to see Riley's car compete in this cool public venue, and to actually be able to watch the race!  We should have adequate time between now and then to repair the damaged axle locks, and to re-tune the wheels to run perfectly again.  There are even some small things that we didn't have time for that I think will make a difference in this race against the best cars in the district.  It's exciting to get a chance to race again against Christopher's first place car.

Next Year

I have some subtle ideas for improving the race next year.  Nothing too fancy, but it could make the experience better for the boys.

Next year, I think I will allow each scout three votes for people's choice instead of just one.  It may make tallying a little more complex, but I think it'll even out the distribution.  The car that won people's choice this year was another (this is a running theme since we've been in scouts) Minecraft-themed car.  It was admittedly a very nicely done car, and in my opinion, deserved first place.  But it would be nice to see some leveling-out of the votes.  If a kid's first vote goes to the one his friends voted for, then the other two might go to cars based on their actual design.  Just a thought.

Also, I'm thinking to make some upgrades and repairs to the track components.  The rubber stoppers at the end of the track need replaced.  They're very worn and don't always work.  We had to put a blanket at the end of the track to catch many of the cars that shot right past the rubber.

I want to do some work on the gate mechanism, so that the gate works the way I've seen on other systems.  Our gate is held up by rubber bands.  To release the gate, you twist the board that holds the pegs that hold back the cars, and have to hold it down until the race is recorded.  What should happen is the gate should be locked in place.  When a chuck is pulled, a spring or rubber band should pull the gate open, and it should remain open without holding it until someone lifts it back into place and re-locks it with the chuck.  Ideally, the chuck would be controlled by the same computer that records race results.

That's probably enough change, though I'd love to add that instant-replay capability I've seen to our track so that the end of each race can be played in slow-motion on the projector.  That would be pretty slick.

It was an interesting weekend for us; there was a lot going on.  Both Riley and Abby had sports events.  On Saturday Riley had a baseball game at Hickory Park and Abby had a soccer game at Fellowship Fields (at which I was "coaching").  Shortly after Abby's game, Riley and I left for Camden to camp on the battleship New Jersey with a group from Pack 32.

Battleship New Jersey

Visiting the USS New Jersey was definitely a unique experience.  The boys from Riley's cub scout pack (and their dads) got to experience a lot of the ship.  The evening tour after mess was pretty exclusive, too.  We got to tour areas of the ship that you don't get to see on a normal walking tour, like the areas inside the gun turrets where the ammunition is prepared and sent to the firing stations.  The tour guide was very knowledgeable, and thankfully very patient with our precocious boys.

We learned a lot of interesting factoids about the New Jersey.  The whole ship is made primarily of steel, which is pretty obvious if you think about it.  But the amount of steel used is astonishing.  Some of the armored doors and walls on the ship are made of solid steel 17 inches thick.

Just one of the three primary turrets weighs the same as a destroyer from the same era as the New Jersey.  That's like having three destroyers on board the ship!  Each gun in the turret fires a huge shell, propelled by 600 pounds of gun powder.  If fired straight up, the shell would reach 17 miles high.

There are "smaller" 5-inch caliber guns on the sides of the ship.  The shells for this gun are stored in the lower decks and raised to those turrets with constantly-moving chain elevators.  These shells are primarily used to shoot down enemy aircraft.  The nose of each shell contains a small vacuum tube that detects when the shell gets near metal, kind of like a poor-man's radar.  When the shell is near metal, like the hull of an enemy aircraft, the shell detonates.  This function of the US 5-inch shell was a closely guarded secret throughout World War 2, and wasn't even shared with our allies.  The shells were never fired over land for fear that one would land, unexploded, on the ground where the Nazis could recover and study it. It is amazing to me that the Axis did not have similar technology, seemingly having all of their shells detonate based on timed fuses.

The New Jersey was in service from 1943 through until the early 90's.  It had been retrofitted with modern weapons from the time.  There were Gatling guns mounted in several places on the sides of the ship for shooting down incoming missiles.  There were Tomahawk missile mounts on the ship for firing these very advanced weapons.  There were even rumors that the New Jersey had nuclear capabilities, but the Navy won't confirm whether this was the case.

One of the most interesting rooms on the ship was the CEC, the Combat Engagement Center. This is where all of the on-board weapon systems were controlled.  The room is the same eerie blue with all kinds of radar screens that you see in movies.  The kids had a lot of fun sitting at the consoles and firing missiles at their enemies.

I had always thought that the doors on a ship were round because of some reason related to water.  Of course, our tour guide said that if water was high enough to be a bother to a door, there were much bigger problems to worry about than the shape of the portal.  No, the door is round because it is structurally more sound.  If a door was rectangular, then when the ship's body has torque - either from weapon impact or heavy seas - then the steel would tear from the corners of the door.  Instead, a round door keeps the ship's body intact under pressure.

We learned how to navigate the ship using signs about the compartment locations.  We toured the captain's quarters, the admiral's quarters, the mess hall, the officer's mess, medical (including an unusually large dental area), and the bridge.  We were able to see inside the turrets at the top, where the guns were aimed and the ammunition was loaded into the barrels.

This was an overnight trip, so we all had to sleep in bunks on board.  The bunks were stacked three beds high, and were claustrophobically small.  Riley and I took bottom beds in separate bunks because that's all that was left by the time we arrived.  Still, the experience was authentic.  At lights-out the lights didn't go out, but instead dimmed to an eerie red color.  All through the night, you could hear the sound of people banging themselves against the steel bunks trying to get comfortable.

The only thing that was a little disappointing was the food.  We usually get such great (too great, sometimes) meals when we camp with the scouts that the chicken finger dinner and hashbrown breakfast were a little small and disappointing.  But a meal is a meal, and we got to experience the chow line first hand, which is interesting in itself.

There was a lot more that we saw and did on the ship, and I'm sure even then that we didn't get to see everything since the ship was so huge.  In all, the trip was pretty great.  Riley had a great time, as he usually does on scouting trips.  I'm not sure I'd sleep over again - not wanting to subject myself to the steel coffin bunk and ensuing back pains in the morning - but I'd definitely visit again, perhaps to join a different tour and see other parts of the ship that we missed.

Riley's raingutter regatta boatOn Saturday, Riley participated in the culminating event of our last week of creative effort, the Raingutter Regatta.  The Regatta is an event for cub scouts that involves using a boat-shaped block of balsa wood, a dowel mast, a plastic sheet for a sail, and a few extra plastic and metal pieces to build a breath-powered boat that can be propelled down the length of a rain gutter filled with water.

The race itself consists of two gutters placed side-by-side, filled half-way with water.  Two competitors' boats are placed at one end of the raceway.  When the signal is given, each competitor blows on his boat's sail in an attempt to push it toward the finish line.  Each scout must use only his breath to push the boat, unless the boat is capsized or stuck, in which case the scout may right or unstick the boat without moving it down the track with his hands.  The first boat to arrive at the end of the track wins the heat.

Riley's raingutter regattaOur pack's races consisted of a best three out of five heats per race, giving each participant adequate opportunity to account for track disparities (each heat alternates the boats between  racing gutters).  The races are single-elimination in a 32-slot bracket.  There weren't enough boats this year to fill the full 32 slots, so byes were given to some of the younger tiger cub participants to allow them to compete in later brackets.

Our adventure begins back at the pack's Christmas meeting when we received the kit for the boat.  The boat materials come in a box that contains everything you need to build the boat except tools, glue, and paint.  Apart from those materials, you are not permitted to use anything from outside the box to produce the resultant boat.

We waited quite a long time to decide on a boat design and begin work.  In fact, we started constructing the boat only six days before registration.  This led to perhaps a hastier construction that we would have liked.

We did some research on the internet for a good boat design.  The Caswell District of Eastern North Carolina provided a very informative PDF on the construction of boats.  The two fastest designs included in the PDF are the catamaran and the hydroplane.  For lack of a good tool for cutting the boat block cleanly in half, we selected the hydroplane design.

The essence of this design is to reduce drag friction between the water and the boat to as little as possible.  Typical raingutter regatta boat designs (if you look at the shape of the provided boat block) are very wedge-like.  For the boat to move through the water, it must push the water in front of it out its way to the left and right.  This creates a significant amount of drag.

Riley's raingutter regattaThe hydroplane design features a significantly tapered slope of the hull, such that when the boat moves forward, rather than moving the water out of the way, the boat itself moves up over the water.  This significantly reduces the friction between the water and boat for a number of reasons, including that there is much less contact surface between the boat and the water than even in some catamaran designs.

The usual advantage of a catamaran design is that the weight is distributed over a virtually wide hull.  This provides a significant amount of stability in what is typically a light and top-heavy boat (with a high sail).  The hull of the catamaran design, if implemented well, also provides the boat with rail-like directional guidance as it moves forward, reducing the need for a rudder.

A disadvantage of the hydroplane is that it purposefully lacks a rudder.  This point was not understood by the pack leader when he observed the design.  The advantage of the hydroplane boat is its reduced friction between the boat and water - one of the only things that matters in the construction of raingutter regatta boats.  By adding a rudder, you significantly increase the friction between the boat and water by dragging the rudder through the water.  Instead, an alternate solution is required for properly steering the boat straight or away from the gutter edges, which are the death-knell of speed.

To better enable the hydroplane boat to control its directon, we produced a hyperbolic sail.  This sail was unique to our boat design at the race, and was the only sail I saw capable of doing what our sail did.  By carefully aiming air at the sail, the direction of the whole boat can be controlled.  You can, in fact, steer the boat with this hyperbolic sail.  This is impossible on any loose mast design (of which there were many at the race), and not as easily accomplished even with the fixed sail designs of many of the catamarans, due to both the non-parabolic shape of the sail, and the increased yaw resistance provided by the catamaran hulls (a catamaran tends to move directly forward, no matter how you blow on the sail, which causes many hand-corrections when waves or hull anomalies cause the boat to turn into the gutter walls).

In addition to its steering properties, the fixed parabolic sail better catches and focuses the air blown at it, resulting in more efficient application of power.  The sail, properly bellowed, can also force the forward hydroplane surface of the boat off the water, thus reducing exposed water surface friction even more. Assuming that you aim the air at the sail properly, these properties can produce extremely fast boat speeds.  Of course, the challenge is that the direction of the boat is entirely controlled by the boat operator, and not at all managed by rudders or separated catamaran hulls.

We used a pocket knife and a small Dremel-like sanding tool to shape the bottom of the boat and hollow out the inside.  The PDF suggests that extra weight in the boat can lower the boat significantly into the water, which will increase drag.  I hollowed out as much as I safely could.  Riley helped sand the boat to a smooth finish, and we filled the pre-drilled hole for the unused mast with wood putty.

Riley, Berta, and Abby all painted parts of the boat.  Riley helped with the base colors, while Berta painted the racing stripes.  Abby painted the Hawaiian turtle design on the sail.

After the decorative painting was complete, I attached the sail to the hull with a hot glue gun and applied a thick layer of polyurethane to waterproof the boat.  The hot glue made for an unsightly finish that I regretted immediately, and seemed not to hold as well as it could have.  The thick polyurethane layer was suitable, but due to the shape of the boat and the haste with which the construction took place (we applied this layer of paint mere hours before registration), the coating puddled in places, leaving an unsightly yellow haze and even some drips.  This did not affect the boat's speed, however.

When tested by me in a Tupperware pool in the kitchen, the boat was insanely fast.  In retrospect, we should have had Riley practice using the boat a bit more, since his unfamiliarity with the control aspects of the parabolic sail would be his undoing.

The first race was a close one, as Riley became familiar with the control aspects of his boat.  He had to run all 5 heats, as his competitor was able to outpace him due to having better control in the gutter, and not getting stuck as much.  When Riley was able to control the boat moving forward without hitting the walls, the boat was rocket-like in speed - without a doubt in my mind, the fastest boat in the pack.  In one of the heats, Riley was able to unstick his boat and come from behind a full 2/3rds of a gutter length, but was only barely beaten in that heat due to a final gust from his opponent.  In the end, Riley took the race, 3 to 2.

In Riley's second race, I think there were many psychological issues.  The surprise of winning one race, the expectation that winning one would result in many wins, competing against the den leader's kid (who wins practically everything, and earned 2nd place only because the boy that beat him was older and had better blowing technique), his parents all giving him advice (some appropriate, some not)...  All of these combined to a net loss in merely three heats.  Riley was very disappointed.  I was disappointed, but not in Riley's performance.

I said at the race that I would not want to do it again.  It's a lot of effort to put into something with very little beneficial return.  It would be better to build for the joy of building than to be under pressure to build for a race, one whose winning is mostly bound to practice that you can't easily achieve.  But as I told Berta, it's like pregnancy: You forget the pain/inconvenience long enough to be convinced having another kid is a good idea.  So maybe this time next year we'll want to do it, and possibly produce a better design.

If we were to build a new boat next year, I think I would stick with the parabolic sail, but apply it to a two-hulled hydroplane catamaran, to get the best of all worlds.  We'd also see about getting Riley some practice runs in a real gutter before the actual race, so that he can work out how to get the boat to go straight and true and fast.