River Test Followup

After our first river test, we decided to change the gear ratio to the propeller and get more data on a second river test! Luckily the weather agreed; today was the first warm, sunny day in weeks.


First, we ran the propeller in a plastic bin, performing a "bucket test" to check the load of the propeller and to calibrate the current sensors.

Then, we drove the boat to the river and let some people drive it around and collect data.

Frank Driving Around

Ibuki Driving

Some more boat driving

Let's hope you're still not counting...

While procrastinating instead of writing this blog, I decided to take a look-see at older posts to see what my predecessors saw fit to fill these web pages. As I clicked from one post to another, a disturbing and yet oh-so-comforting trend began to emerge:

"The spring semester is well underway and so are we! My apologies for not keeping up this semester, but I've got blog fever yet again, so not to worry!"

"Let me assure you that while the blog appears silent, it masks a very productive and busy undercurrent that has produced a new hull design."

"70 days, but who's counting?"

Turns out I am not the only one who struggles with thinking up clever and diverse ways of saying, "Looks like I haven't updated the blog in a very long time." Actually, that last one isn't really about lack of updates...I just read it that way because of how guilty I am. But in my imagination I reach out, pat the poster on the shoulder and say, "No one is counting, buddy, no one at all."

Anyway, see below for a photo update of all that CMSS has been up to so far this semester. And when you finish with that, check out some of the older posts; there are some real gems in there.

After the Activities Fair we held a "Donuts and Fiberglass" event to show interested students the lay-up method documented in the last blog post.

New CMSSers get ready to begin the layup.

Triumph!

Using the heat gun to mold the core to the half-pipe.

Moar molding!

Dunkin Donuts: the ultimate social lubricant.

Bonding with interested students over the boat.

Creating the vacuum seal.

The finished product.

The finished product, unbagged.

Hauling the boat to the first River Test of the year!

In the water.

An unusually lovely day for Pittsburgh.

Backin' her up. I hope he's got on water shoes.

It wouldn't be CMSS without noms.

Summer Core Materials Research

With fresh ideas from competition, this summer we have been researching improvements we can make to our boat!  We have been researching a new drivetrain and hull for the upcoming build year.  Specifically, we are investigating an inboard propulsion system that has the potential to significantly increase system efficiency.

To accommodate an inboard propulsion system, a new hull is being designed.  One item we have been researching for the new hull is core material.  We just performed a test layup with plastic honeycomb and are very pleased with the results.

The fiber glass has been soaked in epoxy and is being applied to the mold. 

The mold is complete and to be left under vacuum for 12 hours.

The layup is being unbagged the next day.

The layup has been cleaned up and looks amazing!

Competition 2010: Back in Pittsburgh

The Carnegie Mellon Solar Splash team has safely made it back to Pittsburgh. We were very excited for the opportunity to go to competition and came back with many ideas on how to redesign our mechanical systems. Although we were not particularly successful, we gained some much needed experience and knowledge that we hope to apply this next school year. Needless to say, the new sprint mount will be chain driven and more thoroughly tested.

Next year holds many possibilities.

Competition 2010: Day 4 - Leaving Arkansas

With both of our lower units out of commision the team was not able to compete today in the endurance event. This appears to be all but inevitable. The maximum continuous power rating the endurance motor could withstand, the Magmotor C40-300, was well under what we were expecting to draw for the endurance event. The added load during the slalom qualifier only expedited the motor's demise.

For reference, during the endurance races we were expecting to run the endurance motor at 24 Volts and 29 Amperes (14.5 Amps from the batteries and 14.5 from the panels, assuming sunny conditions). This exceeded the peak current rating of 20 Amps and far exceed the continuous rating of 12 Amps.


Out of the competition running, we decided to watch both the morning and afternoon endurance races and then leave afterwards.

Competiton 2010: Day 3 - More Qualifiers and Some Surprises

Today we put the sprint mount, and the endurance motor, to a much needed but ill fated test, the slalom event.
We had previously troubleshooted all of the existing problems with the sprint motor mount, but failed to take into account the low tolerances that needed to be maintained in the belt driven system.

With the lower unit properly engaged and the QD bushing set in place, more energy than ever was pushed through the system.  This, combined with the misalignment of the drive shaft and motor flywheels, caused the timing belt to slip off and become shredded.  This rendered the sprint mount inoperable and the boat dead in the water.

Afterwards, we were informed we could redo the qualifier and take the penalty of doubling the recorded time.  This option was selected and instead of using the sprint mount, we decided to use the endurance mount.  We also decided to run the endurance motor at 36 Volts, to try to maintain a somewhat fast pace.  Although the specifications for motor indicated it could run anywhere from 12 to 120 Volts, this mistake proved fatal.  The additional power being driven through the motor at the increased voltage caused the motor to smolder and smoke.  The event was completed successfully, but the motor was no more.

With different parts of  the two mounts malfunctioning, the team attempted to mount an E-tek sprint motor to the endurance lower unit but to no avail.  The e-tek motors drove the sprint mount with a JA bushing, while the endurance motor was coupled with an SK bushing.

This incompatibility left neither mounts functioning, effectively ending the competition early for the team.  As a result, the team was not able to compete in the sprint events today and will not compete in the endurance event tomorrow.

The only pictures I have of today are the disassembly of the endurance motor.

The bolts holding the motor together are being unscrewed.

The bolts have burnt material on them.

The motor windings.

The motor casing.  RIP Magmotor C40-300.

Competition 2010: Day 2 - Qualifiers

We started out the day with the announcing of the scores for the Technical Report.  We received the prize for second place, scoring 88 out of 90 possible points.

Next, we participated in a sprint qualifier, a 75 meter course. Paul decided to slowly ramp up the throttle to check for any indication of slippage that was previously occurring and the noise reoccurred at approximately 40% throttle. Upon hearing the noise, he reduced the throttle and finished the event at a cautious pace so as to not damage any drive-train components.

The next event was the maneuverability qualifier. Austin drove the boat around several buoys to demonstrate the boat's turning abilities. During this event the steering wheel sheered off and temporarily caused Austin to careen out of control. Austin then drove the rest of the event using the rope steering cables. Afterwards the steering wheel was reattached more securely.

In the afternoon, Mike and Paul continued their quest to diagnose and cure the sprint mount. They stopped by the same marina they had been to previously but realized that the problem might not actually be residing in the lower unit but somewhere higher up on the mount. On the way home from the marina they noticed an Autozone car center sign saying, "Parts, Service, and Advice", and decided to see if anyone could trouble should the timing belts on the sprint mount. Amazingly someone at Autozone was able to provide the third option, some advice. He noticed the QD bushing attaching the drive shaft to the timing belt was loose and moving up and down. This was apparent by the chunks of metal screws on the QD bushing had removed.   Upon returning to the lake, Paul tightened the set-screws to the QD bushing.

Tomorrow is the first 300 meter sprint race, and we are anxious to see the how the sprint mount fares.

A much overdue photo, the National Instruments touch panel computer in action.

A closeup of the (previously mentioned) solar panel mounting hardware.

The boat being wheeled over to the water.

Paul accelerating away from the starting line during the sprint qualifier.

Paul is on his way back from the sprint qualifier event.

The boat being loaded into the water, gracefully.

Austin is ready for some action.

Austin received some action.

Barb and Randy Wedler arrived today.


The sprint mount is being repaired.

A circular arc has been scraped out of a supporting piece of aluminum on the sprint mount by screws on the loose QD bushing.