Curved legs gave the table some good leg space, and I always wanted to try making curved wood furniture. Because the table needed to be cheap (<$30) I decided to use cedar for the whole thing. Cedar is great, but not very strong, so I made the legs stronger by laminating them, this also was necessary for bending them.

Using a table saw, I trimmed a 2X2″ cedar board into 3 pieces. I then took a steam iron and ironed each piece while bending it around a male mold. The trick is to go very slowly and keep heating and steaming it with the iron. As the piece went around the mold, I screwed in blocks behind it and then hammered wedges to push it up against the mold and support it.

The final part was to epoxy the legs together and to the table top. All done! You can see it holds up a lot of weight. I finally applied a clear coat to it, and it all looks shiny and consistent. I don’t have a picture of it finished yet as I gave the table away before I could take a final photo.. but I’ll get one someday.

Be sure to see our Flight Video, Photos, and Final Presentation!

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Powerpoint 2007 (13.4 MB)
Powerpoint 97-03 (16.4 MB)

Before I started building websites, my living was made by hustlin’. I would find beat up cars, put a good face on them and sell them. I went through more than a dozen cars before I finished, and it was a lot of hard work! Some were easy electronic fixes, such as replacing a faulty computer or re-soldering a bad fuel relay connection, but others were pretty tough, such as installing new head gaskets, starters and such. Occasionally, I would get a car that just wasn’t worth the parts and efforts it would take to fix it. When that happened, I would tear it apart and list the parts on Ebay. Surprisingly, this usually turned out to be more profitable than actually fixing the car!

Anyways, I ran across some old photos the other day, and thought I’d share.

Before	1986 Honda VF500F	After
	There really wasnt a whole lot wrong with this bike. It just had some fuel feed issues. I ended driving this as my only vehicle for about a year. It was a great bike and I was sad to let it go.                          I started a website for it www.vf500f.com which is still going on to this day.
Before	1975 Pontiac Phoenix	After
	This was a crummy old car when I got it. Lots of rust spots, wheel covers, and a  rusty engine. Nothing some chrome wheels, engine chrome, and an orange pinstripe couldn’t fix! I didn’t make a whole lot off this one, but it was a lot of fun!
After	1997? Pontiac Grand Am	After
	This car was a tricky fix. It took me forever to figure out that you can’t just change out a car’s computer for another… you have to reset the crankshaft position. At least it was necessary on this car. I ended up finding a guy who had a machine for it, and it was top-notch!         Sorry, no before pictures.
After	1993 Honda Civic	After
	I don’t have before pics for this one either, but this was one of my favorite cars to fix. It wouldn’t start all the time so I bought it for a steal, then I found out it was simply a matter of bad Honda soldering which made the fuel pump relay work intermittently. A quick resoldering of the pertinent connections made this puppy good as ever!        It was incredibly dirty, so after fixing it, I thoroughly detailed it and made twice as much as I bought it for. I miss this one.
After	Chevrolet S-10	After
	In my defense, I didn’t lower this truck. I would never treat a truck like that. The guy I bought this truck from had it so low, that I couldn’t find a place to align the tires that had a ramp I could go up without getting stuck. I added some chrome tires I had that were pretty wide and gave me an inch or two more ground clearance. I also made new seat covers, cleaned out the engine and carburetor. Good as new!
Before	1984 Toyota 4Runner	After
	This truck had all four fenders rusted out. A little bit of fiberglass, chicken wire, foam, body filler, and paint fixed it right up!

And there are more, but these are all the photos I could find at the moment. I miss those good old days, I was in a different vehicle every month and always working on something. I ended up going through about 16 different vehicles in the span of 2 years. However, with my website job paying much better money, and some rough run-ins with some scaryish grumpy customers (used cars always breakdown at the worst times), I decided to let this hobby go.

Thanks for watching!

Waterjetting Plywood

This involved seeing good old John Tyler in the Rock Mechanics building. In the basement of this building is a machine about the size of two large skinny cars which is the water jet. A large pump creates high pressures of water which is fed through a tiny nozzle moving on two axises.

This machine is the sickest wickedest. It can cut through pretty much any material without generating much heat at all. It also does it with computer levels of accuracy and a great attitude.

After cutting all our shapes out, we had to let them dry and then just fitted them together. It was like those dinosaur models that you buy and slide and slot together. It was a lot of fun.

There was only one error in our parts, and that was in the main spar of the wing. The file had been made incorrectly and it was a quarter inch too thin. A quick shim fixed all our problems.

The foam you see underneath the plywood is there to give some backing and prevent the cut pieces from moving around too much. Those manly hands belong to John Tyler who did just a cut-out job at getting these parts printed.

Long shot of the Waterjet Machine

Cutting with One Part Already Removed

Cut Parts Drying

You can see from the picture of the parts drying on the table, how all those pieces are just dying to be put together with all their slots and grooves. Thats exactly what we did, and these next few pictures will show some of the process.

Fitting Parts Together

Payload Section with Lid

Checking Straightness / Posing.

Assembling the Fuselage

This script makes a div scroll down with the screen. Its most useful for advertising blocks that you want to always be in front of the user. To use  this script, set the variable ’scrollerId’ to the id of the div you want to be bouncy. Remember to also set the div’s style position to
“position:relative;” as this will allow the div to move. Then simply add the javascript file to your webpage.

Feel free to use this as you see fit. Credit would be appreciated or at least just a link to dejapong.com if you can find it in your heart to do so.

Have fun,

Dejapong

Demo    |    Source

After your initial annoyance wears off, you may also notice something very cool. The ad is bouncy! Instead of just moving to the new position, it acts like its on a spring.

Of course, maybe this is the first time you’ve noticed any of this. Nevertheless, you are aware of it now and you will be told how it does it’s bouncy thing.

Damped Harmonic Oscillation: This is how its done. This is basically a big term for a simple concept. If you compress a spring and let it go, it will bounce back to past its original size, then compress part of the way again, and repeat this a couple of times.
With each pass though, these bounces (or oscillations) get smaller and smaller until the spring stays still, at its uncompressed size.

With out the “Damped” part, this spring would continue to bounce (or oscillate) the same height each time with no reduction in bounce height. Damping reduces the distance traveled with each rebound.

So now, before we dive into any more math and science, heres a little something to wet the beak.

There are three variables in this little program, and here is what they do.

• Mass: The mass here is the wheely thing. As you increase the mass, momentum increases linearly. The final result is more bounces, this is because more momentum means more energy to overcome the energy in the spring. Try increasing it to get maximum bouncing but slower acceleration.
• Spring Constant (K): Some springs are stiffer than others. This is the chief reason for insecure limp springs. Adjust the strength of your spring with this variable.
• Damping Constant: Think of this variable as brakes on the wheel. As this increases, each bounce decreases just like you’ve increased the brakes.

How does all this translate to oscillating linear translation? If you really want technical details, I would suggest wikipedia or Hyper Physics

In class, I always sleep through the derivation and write down the final equation… I feel like it would be the same here. So without further ado, here is the driving equation.

Equations for Spring-mass Damped Oscillation

Calculate (1) and (2), use these in Equation (3) to get the position at a given time t.

We first needed to test our engine, tune it and make sure everything was working. As well, we wanted the static thrust value to see how accurate the advertised specifications were.

Test Stand with Force Gauge

Our test stand, as shown above, is a simple wooden stand with the engine mounted on a floating platform connected to a force gauge. This allows the engine thrust to register as a force on our gauge.

Although it took a while to get the engine started, we eventually got it running smoothly and recorded a static thrust load of close to 12 lbs.

Trying to Start our Brand New Engine

All propellor driving engines lose thrust as the ambient velocity increases. Because of this, to accurately predict our top speed we need to know how our engine and propellor combination perform at speed.

Yours Truly, Intently Documentating

The thrust data at varying ambient velocities are called dynamic thrust data.

Dynamic Thrust Test Stand Mounted in Pickup Bed

The best way to test something like this would have been to put it in a wind tunnel where air velocity could be accurately controlled and laminar. Our main problem with this was the large quanties of motor fuel and exhaust fumes that our engine belched. Because we didn’t want to spend days scrubbing out wind tunnel vanes, we opted for a less controlled, but perfectly valid back-of-the-pickup test. Below you examine our methods (high in science).

John Fiddling With the Engine Prior to our First Test Run

This method is very simple.

1. Put the engine on a test stand in the back of a pickup.
2. Drive that pickup as fast as possible.
3. Try not to kill the person in back since he has the numbers you need.

John Trying to Keep all His Fingers

Our test stand was the same one we used for our static thrust test. Of course someone had to be back there reading the numbers and either writing them down, or memorizing them. That person absorbed most of the liquids and gases spewing out the exhaust.

This is a Good Way to Save Gas

Our testing method was to increment our speed by 10mph and check the force reading. We only dared go to 60mph with John in the back, since he is a very light guy and could be blown out by passing wind, or by a gust of wind. We would then just extrapolate the data we needed from our thrust curve. We assumed a linear curve, which is probably not true, but good enough for our case. Most curves stay fairly linear before dropping off suddenly.

Thrust (y-axis) is in pounds. Speed (x-axis) is in mph.

Our results were very encouraging. We had almost 12 lbs of static thrust and 8 lbs of thrust at 60mph. We extrapolate around 4lbs of thrust at 100mph, which is almost twice what we need to maintain that speed (2-2.5lbs of drag at 100mph). So we feel pretty confident that we will achieve our target airspeed. John also thinks that the engine is still running a bit rich, so with a little bit of tuning, we might eke a few more ounces out.

As a side note, John still smells like engine fuel.