The Results...

The first official flight should have been REALLY SUPER GOOD. We had a 47 second flight time, but our altimeter reported an unrealistic 270 feet. It was a beautiful flight, and had our atimeter worked properly, we would've started packing for D.C. But it didn't. The officiator is going to contact Trip Barber of the NAR to see if we can get a re-do flight for that one. I hope we do, but if not, we can be proud of the good job we did.

The second flight wasn't as good, but at least the altimeter worked. We only got 681 feet, so the flight time was only 33 seconds, disqualifying us for that flight. Also, the streamer dropped like a rock, which is unexplainable since it was exactly the same streamer.

We're hoping for a re-do flight for a chance to prove ourselves! Go Andover!

From left: Me, Sam, Phil, Matt

Me, climbing the tree to get the egg capsule/altimeter down.

Rocket Team at work

Me and my family are going out of town over spring break. We're driving all the way down to Florida to visit a college, Embry-Riddle Aeronautical University, where I hope to enroll in the fall as an aerospace engineering student. It's going to be a very informative visit.

We happen to be down there at the same time NASA will be launching its fourth to last shuttle flight ever, April 5th. Since I've never seen a shuttle launch in person before, I never will unless I do on this trip. NASA is retiring the shuttle this year.

If I'm not able to blog on the trip, expect an exciting post filled with adventures on April 7th!

Don't Hold Your Breath, But We're Getting Close!

Monday is the day. Tomorrow is our official flight. If we're in the top 100, we go to Nationals in D.C. If not, we just pat each other on the back and say, "Well, it was fun anyway."

So far our best altitude was 810 ft. and our best flight time was 51 seconds. (We had a 36 second flight but more points are taken off for being under 40 seconds than over 45, if that makes any sense at all. That's probably because it's harder to make the rocket descend slower with a streamer than faster). Now if our rocket can just behave itself for the official flight, we'd be in good shape!

Getting Some New Ideas

We obviously need to have the egg come down much more slowly, so here's the current plan:

We encased the egg in a large, colorful plastic Easter eggshell (like for egg hunts) with its very own streamer. The rest of the rocket is rigged to come down with a parachute. There is nothing in the rules that says the rocket can't come down in two pieces, we only need a streamer on the egg capsule. So the egg capsule/streamer assembly is its own separate entity inside the recovery bay. To ensure that it comes out of the tube upon ejection, we stashed the parachute above the egg capsule so when it deploys it pulls the system out of the recovery bay.

I did some drop tests from a tree today, and it fell 19 feet in 1.42 seconds. That should be more than enough. v=d/t, v=19/1.42 = 13.4 ft/s, t = d/v, t = 825/13.4 = 61 seconds. We're shooting for 40-45 seconds. If it's over, that's GOOD, because it's easier to be under than over when it comes to flight duration with streamer recovery.

Another thing I tried to increase drag was to fold the streamer like an accordian and tie knots in the creases with thread to hold the shape, as in figure 3. This exposes a lot more surface area, plus it flutters better. It should be great.

Figure 1

Figure 2

Figure 3

Hmmmmmmm...

We're getting some interesting results. The first flight was ridiculous.We forgot to drill a hole in the body tube for the altimeter to sense pressure changes, so it told us something ridiculous like 350 ft. The second flight was even ridiculouser. The altimeter gave us a whopping 170 ft. After a thorough inspection, it turned out that SOMEBODY drilled the hole in the wrong end of the body tube, the recovery bay end. That was promptly fixed, and then, after the third flight, we check the altimeter and it's telling us 1621 ft. Are we supposed to believe that, after the junk it's been giving us? Perhaps we're doing something wrong. Well, either way we're doing something wrong, and we have a deadline staring us in the face. AHHHHHH!!! Everybody panic!!!

Last One to Launch is a Rotten Egg

Take my advice: don't leave your payload couped up inside your rocket for two months. It kinda stinks when you pull it out to inspect it for your next launch. Even the altimeter is stinky. Needless to say, we are going to need a new egg for today's launch (if the weather holds). We don't want any broken rotten eggs on our hands, or in our rocket.

How'd We Miss That?

I recently looked at the official rules for the TARC contest, and it turns out we are supposed to be using a streamer for recovery. That changes things a bit. Quite a bit actually. At first it didn't seem like our design could slow down enought under a streamer, but it turns out there's more to streamer recovery than meets the eye. There is an entire science behind it. For instance, most people seem to think that you want a really really really long streamer. Not so. For the maximum drag coefficient you want a length to width ratio of 10:1. According to the simulations, a 9 by 90 inch streamer will bring our rocket down in 50 seconds, which is more than enough time.

I'm just glad I caught this as early as I did. We still have at least a month before the deadline.

Today we did some painting in the Tech Ed department. My ears are still ringing from all the noise that goes on in there. Its going to look pretty good, but I entrusted too much of the painting to the freshmen and we got some nasty globs and runs. Its actually not too bad, I just like to give them a hard time.

First Test Launch!

We just conducted our first two test launches of our TARC entry. We have been really pushing ourselves to get ahead of schedule so that we can fit in as many test launches as possible before the official ones this spring. The snow on the ground complicates things just a little, but it actually saved our rocket. The first launch went well on the ascent (the easy part), but when the 24-inch plastic parachute came out it ripped right off and drifted away. The rocket came tumbling down in fifteen seconds and buried itself in the snow. Had there been no snow, the collision would have resulted in some serious damage.

So we ran back to the physics room and grabbed our spare chute. This was a heavy-duty ripstop nylon one, whose shroud lines were stitched right into the canopy. It wasn't about to fail anytime soon, but it was considerably smaller, hence our flight time was still only thirty seconds--ten short of the forty-second parameter. However, the flight was absolutely spectacular.

There isn't any altitude data yet since we are still waiting on our altimeter. Some people tried measuring an angle, but a hundred feet isn't much of a baseline...

Suprisingly our egg survived! After its harrowing first flight we took it out to examine it. Just a few hairline fractures in the shell, but it was still alive! We placed it back in its well-padded cockpit for the next flight, which went beautifully. Our egg survived a flight with fractures in its shell!

Here it is!!

Pictures!

Our TARC entry is now complete! Hopefully it will perform as good as it looks.

I've never worked with phenolic before, so it was kind of interesting trying to cut the slots:

I also have never attached the fins before gluing the whole assembly into the airframe, but I think it works better this way.

...And it slides right in:

Here our completed rocket poses next to its portrait:

 I haven't mentioned the Team much yet. I think we have the perfect balance of skills and talents on our team, from freshmen to seniors, from all interests and abilities. In all we have six members. This has been a great experience. I always thought that collaborating with others produces better results, and it's true. Apparently two horses can pull four times as much as one horse. I'm not sure if that's scientific fact or just a myth, but it's something I've heard before.

I smell another project coming on...

One with a biiiiiiiiig blast deflector!

P.S. -- My computer is still not working, but I'm pretty sure it's a hard drive failure. So once I get a new hard drive, you should expect to see more frequent posting.

Computer Issues and an Update

I'm posting today from a school computer. I regret to announce that my computer is almost permanently disabled. It has a problem where it begins to boot up and immediately shuts off. Some computer geeks at school (that is, geekier than me) are going to see what they can do, but there isn't much hope. My posts will probably become rather infrequent or irregular... But here's an update:

Our TARC entry is nearing completion. I'd post some pictures, but I don't have any. We're hoping to get at least 10 test flights done before March. We also have a few new members, making a total of seven. Now that my computer is on the fritz, our computations are going to be rather crude, or nonexistent. But the more test flights we do, the closer we can get to 825 ft and 40 seconds, RockSim notwithstanding.

The Chickens are Laying!

Don't be alarmed, I'm not ready for the funny farm, but I really am excited. You see, I'd started some research on the strength of the shell of various egg options for the TARC contest, but I couldn't finish it until the chickens started laying eggs. So far I've discovered that a typical store-bought "large grade A" hen egg can withstand about 24N of force before cracking. I now have three more possibilities: white, brown, or green.

Rocket Team Update

Our rocket team at school has been making some great progress in preparation for Team America Rocketry Challenge (TARC) 2010! We "finalized" our RockSim design, and are now going to start collecting parts. I made a fiberglass transition piece this afternoon, and considering that I always have trouble with the fiberglass and epoxy getting everywhere, I think it turned out rather nicely. One of the kids' (there are four of us, three freshmen and me), grandpa has a lathe, and he's going to see about making a few balsa nosecones for our project.

As we build it I'll be sure to post pictures of its progress. I've also been getting goofy doing mini research papers on the durability of certain types of eggs. I'm very fortunate to have three kinds of chickens at my disposal.

Rocket Team

An amazing new opportunity has come my way: My physics teacher, Mr. Shaffer, is the leader of a small club at my school called the "Rocket Team." The goal of the club every year is to build an egg-lofting rocket to enter in the Team America Rocketry Challenge contest. Every year the rules for the contest are slightly different. This year, we launch an egg to 850 ft and have a total flight time of 40 seconds. Any differences in altitude or time aloft give you points. You don't want points.

And here's the best part about it: if you score in the top 100, you advance to nationals in Washington D. C.! The winners of the national event each receive $10,000 scholarships. This is definately worth some time and energy. A cool thing about nationals is that a lot of head aerospace companies and defense people are there. You could very well just walk into the crowd and start talking to the CEO of Lockheed-Martin. Some great connections can be made there, needless to say.

I hope we do well! No matter what though, it will be a great experience.