Mojave Weblog
Site with some cool photos for rocket and space enthusiasts:
Level 1 Achieved
I acheived a milestone in high power rocketry this weekend by certifying as Level 1. For non-rocket types, that means I can now fly H and I motors in my rockets. If you’ve ever flown model rockets, you are probably familiar with the small A motor. Each letter is double the impluse in Newtons of the previous letter. This makes an H equal to 128 A motors and an I equal to 256 A motors for anywhere between 160 and 640 Newtons of total impluse. Pretty cool, huh?
So here are some pictures of my rocket and flight:
This attempt was made at MRFF 2005 (Midwest Regional Fun Fly) at Bong State Recreation Area, about 10 miles west of Kenosha, WI. The rocket is a PML Tethys built almost completely stock. Instead of the included launch lugs, I opted for PML rail guides. Also, since I may fly this on a small J motor for a Level 2 attempt, I used PML’s expanding foam to fill the cavity in the fin can. This provides strength and stability in the the fins without compromising weight. Lastly I added PML’s motor retention (I just bought Dr Rocket’s 38mm motor hardware. No way am I friction fitting my motor for this flight!). The motor for this flight was an Aerotech H123 White Lightning, medium delay.
It was a pretty successful flight… right up to the point where it landed in a rocket-eating tree. It took my dad and me about two hours to retrieve it (What better way to spend Father’s Day Weekend that helping your fully grown adult son get his rocket out of a tree). At that point, I wasn’t as concerned about actually certifying as I was about getting my brand new 38mm motor hardware back. But in the end, I was certified.
Thanks to Tim Lehr of Wildman Rocketry for all his help!
For non-rocket types, flyrockets.com has some good info on How Rockets Work. They also have good pictures if you want to see what these things look like.
Level 1 Attempt
Well, I had planned on attempting my Tripoli Level 1 Certification (that’s High Power Rocketry lingo for H and I motors for you non-rocket types) at the Midwest Regional Fun Fly. MRFF is usually put on as a joint effort between NIRA (Northern Illinois Rocketry Association) and WOOSH (Wisconsin Organization Of Spacemodeling Hobbyists). However, this year it looked like only NIRA would be there as they were the only one’s with it on the calendar. As such, I scrubbed my plans to make a L1 attempt. NIRA dropped their Tripoli association (I believe), and I prefer to certify with Tripoli since most of the HPR (High Power Rocketry) launches I attend are Tripoli. WOOSH is a Tripoli group, but it looked like they wouldn’t be there.
Now I see that they have it on their calendar. They also have this nifty little handout. So it looks like my attempt may be back on.
The problem is, I slowed way down on construction of my L1 project since I didn’t expect to be launching it this weekend. Granted, there isn’t that much left to do, just finish the paint and install motor retention. But with limited time between now and Saturday, that may be a bit of a scramble to complete. So I will scramble and get it flight ready by Saturday morning.
If there is time, I will post pictures and details of the project from start to finish.
Further Optimization of the W3C Validation Images
So call me picky, but I went ahead and tried to further optimize the process for using the W3C validation buttons. I know that seems like trying to eek out another 10 horsepower from a 400 horsepower sports car, but it really bothers me to reduce efficiency for something so useless (which brings up the point, “Why use them at all?” but that’s another story).
I felt that I could probably create some efficiencies by combining the images and using an imagemap for the links instead of using two separate images. There are basically three potential areas then for optimization:
- size of the html on the page
- size of the single image vs. two seperate
- reducing the images requested from 2 to 1
Note that this whole process is only an option if you actually have both valid XHTML and CSS. If either of these don’t validate, you need to just use the one image for the one that does validate.
Ok, so here is what I did:
I started by combining the two images into one single image:
This allowed a reduction in server requests from 2 to 1. Instead of asking the server for and image, then another, the browser only has to ask for a single image here. Also the total size of the single image is 1287 bytes. Compare this to 1441 bytes for the combined images. (Note that I am using 16 color gifs for both of these, as opposed to the 128 color originals. See my post on this.)
The second part of this process was to change the html to call the single image, use an image map to separate the links, and make sure it was valid XHTML, then measure the results in bytes.
342 bytes the old way:
alt="Valid XHTML 1.0!" height="31" width="88"
class="graphic"
align="middle" />
src="/images/w3c/w3c_css_16c.gif"
alt="Valid CSS!"align="middle" />
396 bytes the new way:
So, the html for the new way is actually a little bigger. But that is ok because our total weight of the images combined with the html is actually less. 1783 bytes the old way, 1683 bytes the new way – we save a total of 100 bytes. Doesn’t sound like much, does it? So I guess we will justify the whole process by saying that we’ve reduced the hits to the server in this process from 2 images to only 1.
Like I said, it’s like eeking out an extra 10 horsepower from a 400 horsepower engine. OK, maybe more like an extra 5, but it was fun, wasn’t it?
Optimizing W3C Validation Buttons
I was recently working on one of my sites and had added the W3C buttons for valid XHTML and CSS (which actually validate, by the way). I regularly run speed reports on my sites as well and when I added these two buttons, I was not pleased with the result. Call me picky, but the extra image weight wasn’t necessary for what these buttons are. Since they are more for show and don’t really serve purpose for the user, why add the weight?
So I took the buttons and reduced the number of colors in the gif to see what we could do without losing too much in the way of image quality. The originals were 128 colors. I found the least I could reduce it to and without losing too much quality was 16 colors. The results were pretty good, I think. The XHTML button was reduced in size from 1.68k to 805 bytes. The CSS was even better going from 1.23k to 656 bytes. Now I can load both buttons for less than the cost of the original XHTML button.
Here are the results. Feel free to use them in place of the originals (if your pages do in fact validate).
| Original (128 colors) | Optimized (16 colors) |
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