Friday, July 31, 2009

And now with my simplified HTML...

20092008
5
11

1
0

6
0

25
14
19
13
21
7
12
2
2
0
0
0
0
0
0
0
Mtr:MMX¼A½AABCDEFGH

My motor usage by impulse class




2009
2008


5
11


1



6



25
14


19
13


21
7


12
2

2




























Mtr:MMX1/4A1/2AABCDEFGHIJKLM+unkn


Code shamelessly stolen from Dick as my html-fu was not nearly up to the task.

Day 2 in Hawaii

We went on a heliocopter tour of Kauai today. Absolutely amazing - there's simply no good enough adjectives. Incredible views of the canyons, waterfalls, knife-edge ridges, and sheer cliffs of the island. We flew up the same valley that they fly up in a chopper in Jurrasic Park, as well as seeing spots famous from other stuff including Gilligan's Island and Six Days Seven Nights.

The pilot happened to mention that there was a sucessful missile intercept test yesterday, and this now makes yesterday's observations make sense. The first trail I saw was the practice missile being launched from the range on the island; the second was the ship-launched interceptor, whose trail drifted into sight a while later.

I got to go snorkeling quite a bit today - the ocean is around 80° F and some beaches have rocks to break up the 8-foot waves. I saw a number of fish around the rocks, but these ones, saddle wrasses, are my favorites:

Thursday, July 30, 2009

In Hawaii!

So yeah, I'm in Hawaii. Poipu in Kauai, to be exact.

A few random notes:

  • Somewhere about over St. Louis, give or take 300 miles, I happened to be looking out the window at just the right time to see another jetliner pass no more than a mile, probably less, off out left wingtip - this seemed to be a very close pass.

  • After running a few sims on the plane: Estimated altitude for the Nike-Apache on an H128W-M is 1800 feet.

  • We have only one wired internet collection in our room, but 4 people wanting to use 2 computers. Fortunately, we happen to be in an area that, though not insanely crowded or uber-urban, has the critical mass required to have a few people too careless to secure their wireless networks in the area. Quoth xkcd: We need a special holiday to honor the countless kind fools with unsecured networks named 'linksys'.

  • Twice today I saw the distinctive bright, twisted smoke trails that can only be created by the smoke plume of a large rocket. I think they must have been test flights out of the PMRF.

  • Although I'm 6 hours behind the East Coast where I usually blog from, I'll be using the local time for my posts, so you'll see posts appear 6 hours or so after their timestamp, usually around 3pm or 4am EST.


Actual updates on what I'm doing here start soon.

Wednesday, July 29, 2009

Hawaii!

As of 700 am this morning, I will be leaving to go to Hawaii. I will be there until the 7th of August. I am bringing my laptop, but blogging will be light and not meet my post-a-day target.

There will be a full recap posted on the 8th, then lots of juicy rocket goodness including NERRF and my certification flight.

Thank you for your patience.

Tuesday, July 28, 2009

Introducing Drowning in Turtles!

For a bit I've been working on Drowning in Turtles, a new and mostly original webcomic drawn by myself, a friend known to the internets only as 'Laura', and the one and only mandachan of Divided loyalty. It's mostly about our awkward adventures in study and school, with a few jokes from our personal lives and some xkcd-style stuff drawn but me. It'll update only occasionally, though I hope to maintain at least 2 strips a week.

NERRF lineup Mk. 1

  • Nike-Apache on an H128W-M or H165R-M, with the possibility of an H97J-M if neither of the previous two are available. This will be my Junior Level One Certification flight. Estimated altitude 2400 feet.

  • Machnum Force on a G80-13. Estimated altitude 5600ft; speed Mach 1.14 (868 mph / 1273 fps / 388 mps). It'll recover on a smallish streamer at about 40 fps, but even at that high speed it'll take over 2 minutes to reach the ground!

  • Deltie Thunder on a D12-3. Estimated altitude 250 feet; if it comes out gliding at 200 feet AGL then it could easily glide for well over a minute; if it repeats the previous two flights then it may becomes scrap balsa.

  • Mozzie on an F23-4FJ. Estimated altitude 943 feet, estimated speed 266 fps. Time aloft approximately 30 seconds.

  • Nantucket Sound on an E18-4W. Estimated altitude 300 feet. I'll make sure to tape the motor case in this time.

  • Comanche-3 on D12-0 / B6-0 / A8-5. Estimated altitude 2000 feet, estimated speed 400 fps. Hopefully my first stable three stage flight.

List subject to change.

Another motor order

From Hobbylinc:
  • A10-3T; 1 4-pack

  • A8-3; 1 3-pack

  • C6-5; 1 3-pack

  • D12-3; 1 3-pack. One will launch the repaired Deltie Thunder at NERRF, hopefully for its first sucessful flight.

  • F23-4FJ; 2-pack. I wanted F27 Redlines, but Hobbylinc was sold out of those with the 4-second delay. I chose the Fast Black Jack motors because they're pretty spectacular motors, and the 4-second delay so I can use one in the Mozzie at NERRF and one in the Nike-Apache or another largish rocket later.

Mosquitos

Finally rebuilt the 1x Mosquito. All original parts except for the body tube. Coated the balsa fins and NC with wood glue. Took it and the 1.5x Mosquito, both of which were originally colored by sharpie. painted them with rattle-can spray paint. Both look nice.

Also, hate the real mosquitos - the bugs. Itchy!

Take-Apart: Building

Yeah, it's been a while since I did any other posts about taking stuff apart.

Now, the backstory: My dad is a doctor who is a part-owner of his practice along with another doctor. They're moving to a new larger location and building their own building. It was cheaper to find a lot with a building already existing, to take down, than find an empty lot, and this way they could use the roof and foundation over. However, the walls and hung ceilings are to be destroyed, starting today. So, because it would all be destroyed anyway, we got to go in on Sunday and take any useful stuff.

He found a number of hanging blinds, plus a few special light bulbs and outlet and switch plate covers.

I got several large speakers, two with attached audio transformers and one with a complete audio board attached. I got some nice terminal blocks. I got an infrared sensor, with a super-bright LED and a weird sensor.

I also took a weird-shaped green LED from a thermostat, an interesting and useful board from an emergency light, some nice parts from an old, deactivated alarm system, and the entire electronics from a garage door, including the 20-pound motor.

More later, maybe.

Monday, July 27, 2009

Crazy Idea of the Day #2

So, now that I have finished the Nike-Apache, I'm eager to aquire a small set of rockets that can be flown with the larger mid-power motors at the Salem field.

I have the Mozzie, which flies decently on Ds to 300-350 feet and on Es to 600-850 feet. However, on windy days F flights to 1200-1600 feet are tricky, and most flights on Gs will top 2000 feet, which makes it very easy to lose the rocket.

The Nike-Apache will fly decently on higher-thrust E motors to 400 feet and on Fs to 500-800 feet; it's also the only rocket I can fly regularly on Gs as it tops out at about 1500 feet max, and some only barely break 1100 feet.

I'd like to aquire another rocket with a 29mm mount. Light enough to fly on Gs, but strong enough to take the full hit of an I200. Probably 3" or 4" in diamater, with a payload section, 1/4" plywood TTW fins, rail buttons, yaddie yadda yadda. I'd also like to be able to compete in the annual CATO pumkin chunkin, which means either a 4" rocket so the pumpkin can fit inside, a 3" rocket that can us it as a nose cone, or a creative method: duct tape?

Thoughts? Kit suggestions? Know any place to get 4" tubing and a 4" nose cone on the cheap?

Sunday, July 26, 2009

Crazy Idea of the Day #1

Not going to be a regular feature, just I happen to have two of them today that are both big enough to have separate posts.

Okay, so the first crazy idea. This came about while building my Nike-Apache a few days ago. I noticed that the Apache on its own could be a good rocket with a few simple modifications. It's a solid 24mm minimum diamater model that only requires retention and a recovery system to turn it into a workable rocket that still qualifies it as a scale model.

However, the main idea is even cooler. Basically, the Nike-Apache kit is a very high-quality kit of a Nike booster that can be changed very easily and combined with other materials to make different models of Nike-boosted sounding rockets, all it the same scale.
  • For example, with new fins on the both stages and a small balsa or paper thickening/transition just aft of the nose cone, one can have a Nike-Deacon.

  • With just a slight thickening of the forward section near the nose cone, you can have a scale Nike-Cajun, which was actually the predecessor of the Nike-Apache.

  • With new fins in the forward section and leaving out the thickened forward fin can, one can make a pretty good Nike-Asp.
  • The Apache, Cajun, and Asp are all about the same diamater; the Tomahawk is somewhat thicker and would probably require you to re-turn part of the transition section to fit the larger tube; This wouldn't be too difficult with a lathe or largish drill and vise or drill press. To be in scale with the Nike, the Tomahawk would have to be about 1.45" (37mm); this could be thick-walled 29mm or 32mm motor tubing. Unfortunately, there's a gap between BT-56 (34mm) and BT-60 (42mm) with nothing really in between.

  • More difficult would be the Aerobee 350. First, there's the interstage structure, which requires a completely different transition, strong struts, and an electronic ejection system, more than likely, as the forward section is larger and probably heavier than the Nike body. Second, the Aerobee body is big - it requires a body tube about 3.5" in diameter, which is an odd and hard-to-find size, and might have to be custom made especially with the nose cone; it'd also have to be about 57 inches (4 foot 9) which makes for a giant rocket. Third, since it's a big rocket - about 10 feet tall and 3.5" wide - it's pushing several boundries, including the 3.3 pound limit, the limit of what three skinny interstage struts can hold, and also the lifting capacity of a 29mm mount that's designed for F-G motors. However, with a longer motor tube, I think a careful builder could easily fly an I200 so long as they reinforced the centering rings with plenty of epoxy and fillets. I plan to fly an H128 and possibly later an H165 Redline in my Nike-Apache, with wood-glue-covered centering rings and epoxy fillets on all four CR-motor tube joints and one CR-tube joint.

  • Finally, there's the Nike Smoke. This is the most difficult because it requires a huge custom nose cone. If you want it, then just get the kit from the same manufacturer, Cosmodrome Rocketry.

Saturday, July 25, 2009

Nike-Apache Pics

Finally, the long-awaited pictures of the damn thing. My mom's camera unfortunately doesn't have as much megapixelage as my dad's, but it helps to hide the imperfect paint job.

As always, click on pictures to embiggen.

Nike-Apache Here it is in all its glory. Not much to say for this one, other than to note that it took me about 20 hours of time to build it; a third of that was painting. Thus, the amount of my time this is worth is almost 3 times the price I paid for it.

Total length is 52.5"; diameter of the Nike tube is 2.6" and about 2.75" for the transition. Five colors: grey / primer, silver, black, white, red.

Also, note that I've figured out how to add mouseover text for the pictures.


Apache Here is a bit closer-up view of the Apache section. Only 3 big things here:

1)Note how the grey and silver sections up front create a neat but subtle contrast.

2) Note the nice knife-edges on the fins. Those took an hour total and were the second most difficult part of the rocket after the fin slots.

3) If you ever happen to build one, make sure to cut the fin slots for the Apache so that the fins butt up right against the rear centering ring so that they don't protrude into the black section. Mine have about 1/4" of black and it doesn't look great, though still okay.


Fuzzy pic of Nike fin can A slightly fuzzy pic of the Nike fin can. Note the nice shiny smooth red fins and the launch lug, one of two, which is on standoffs to clear the Nike transition and prevent scratching the paint with the rod.

Note also the gold board underneath; this is a homemade stand for the rocket. It's about 8x10" and 3/4" thick. A 6" length of 1" dowel, wrapped with tape to 29mm diameter, is nailed to the board and is inserted into the engine mount. A 1/4 hole goes through the board to accept the retainer rod, then widens to 1/2" so that the nut and washer can be tightened to firmly attach it to the board.


L→R: Mozzie, Nike-Apache, 29/180 case, yardstick, Comanche-3, Machnum Force From left → right:
  • Mozzie (my only other 2.6" rocket; 19" high)
  • Nike-Apache (2.6" diameter, 52.5" high)
  • 29/180 case (what I'll use for my cert flight; 1.13" diamater and 7.3" high)
  • yardstick (1" by 36")
  • Comanche-3 (previously my tallest rocket at 39" high and 1" diamater)
  • Machnum Force (one of my 3 29mm rockets; 1.15" in diameter and 17.4" high).

Just a comparison with some of my other similar rockets.

One final thanks to Snipplr for the html code for the arrow.

Posted by Picasa

Nike-Apache #9: Finished!

I did lots of painting today on the Nike, including the transition which glues to the Apache. First 2 coats of primer, which went on well and looked good. Next came three coats of white paint, which didn't come out perfect but still pretty damn good. Then I masked off everything but the fins and painted them with two nice shiny coats of apple red.

After those 7 coats were all finished drying, I cut out and applied the decals to the Nike body, then clear coated everything - from the Apache tip to the Nike fin can - with a coat of clear gloss enamel. Shiny!

Then I wood glued the Nike transition onto the Apache fin can, then set it onto a beanbag to dry and not damage the antennae. Finally, I threaded the chute protector onto the nylon shock cord, tied the cord to the quick link and eyebolt in the transition, and tied a loop for the parachute.

Once everything's dry in the morning, literally all I have to do is attach the quick link to the steel anchor and tie the chute to the shock cord.

Pictures will be coming soon, then an EMRR review probably after the first flight, or maybe after the cert flight then a G flight at CATO.

Due to the steel threaded rod for positive motor retention and the 1/8" protruding part of the motor tube, the rocket does not sit on its rear end. Since it's too heavy to hang from the ceiling, I'll have to make a stand for it out of some scrap wood and a dowel.

Service Pack 2

Had to install Vista SP2 tonight. It was remarkably painless. The 349.3 MB of updates took about half an hour to install, which works out to 194 KB/s, which is close to my nominal internet speed (stupid slow wireless connection) and about 10 times faster than my download speed for programs, files, and such.

It was stuck at 12% for about a quarter of the download time, which prompted me to draw an xkcd-style comic on the matter. I might post it soon, if I can borrow mandachan's scanner.

Installation was pretty quick and easy - it said an hour plus and multiple restarts, but mine invloved only 40 minutes and one restart.

Friday, July 24, 2009

Burning Ship Fractal

Just happened to discover this while browsing Wikipedia last night. It's a very cool fractal called the Burning ship fractal. The mathematical definition of it, rendered in Tex (thank you Wikipedia) is:

z_{n+1} = (\operatorname{Re} \left(z_n\right)+i\operatorname{Im} \left(z_n\right))^2 + c, \quad z_0=0


What this means, in simple terms, is the following. Start with the first number, z0, as 0+0i. Then repeat this loop:
1)Add the absolute value (distance from 0) of the real part (the non-imaginary part) to the absolute value of the imaginary part (the part with the i).
2) Square the sum.
3) Add an arbitrary (I think) constant, c.
4) Plot the resulting point on a graph of the complex plane, with color showing how many iterations it takes to reach an arbitrary large number.

The imaginary part can be subtracted instead of added; this produces a more clear image of the 'burning ship':

The picture is smaller because it loads slow; for the full desktop-sized beauty, click the picture.

The burning ship fractal is similar to the Mandelbrot set, except for the absolute value function that induces the assymetry. It is an example of a complex quadratic polynomial.

Thursday, July 23, 2009

Nike-Apache #8: Technically nothing new...

Okay, I lied. I put the decal on the Apache. Looks nice.

But anyway, the epoxy is dry on the fins and launch lugs. It's currently is the midst of delivering 2 inches of rain tonight, so primering will start tomorrow. 2 coats of primer, 2 of white, then 2 of red on the fins.

Flabbermazing

Flabbergasted+amazing. So amazing that you're utterly speechless and so your flabber is completely gasted. I invented it during conversation with my sister today.

Nike-Apache #7: am I done with this !@#$ing glue yet?

The answer: mostly.

The Apache is not completely finished. I brush-painted the solitary black stripe on the 2429 transition, and it looks pretty good - really brings out the detail on it. It will be finished once I apply the decal.

All four fins on the Nike are glued on with wood glue, and filleted on the outside with wood glue. Apparently you're supposed to leave the aft CR off and put internal fillets on the fins, but I read the instructions wrong and I put both on. Since I'm not going for scale accuracy, and am willing to put on outside fillets, It should be just as strong.

I then glued the launch lugs to the balsa standoffs and on, aligning them with my 1/4" rod. I glued on fillets and sealed the balsa wood.

I then took a sizable amount of epoxy clay (I've still got 80+% left, though) and put fillets on all four fins plus the launch lugs and standoffs. Those will be dry tonight, and I'll start the primer on friday.

I also put more wood glue on the transition. One layer on the exposed surface for smoothness, one on the shoulder for fit, and 3 on the base for protection from the ejection charge.

After the primer, I'll need two coats of white on the body and transition and one or two of red on the fins. After that, I'll install the recovery system and connectors, apply the three total decals, then glue the Apache to the transition and be done.

Wednesday, July 22, 2009

I feel special!

I won the week 7 of Malestrom's Genius of the Week puzzle. It was tricky, but basically invloved figuring out that the letters of BECKWAGSQM were the prime letters of the alpabet. (B=2, E=5, C=3, K=11, etc).

So basically, if you're coming here from Malestrom's blog, welcome. I try to entertain.

I also feel special because I have a bit of a secret project underway; it'll be officially announced in a few days.

Tuesday, July 21, 2009

Impact on Jupiter!

JPL releases observations that show that Jupiter got whacked with something big. It's not quite as big as the Shoemaker-Levy impacts of 1994, but it's still very impressive and possibly may become observable.

A 1.65-micron image from the Infrared Telescope Facility in Hawaii:


The smallish bright spot on the bottom is the new impact, which looks black at visible wavelengths.

Nike-Apache #6: the beginning of the end

First the Nike because it's less exciting. The wood glue on the forward centering ring finally dried, so I flipped it back over and did the epoxy fillet on the aft one. After the 24-hour drying period, I glued on the first fin using wood glue. It finished drying about an hour ago and the second one is drying now.

As for the Apache, with the epoxy I made mini-fillets on the fin-2429 transition joints, plus glued the weight and nose cone on securely with the clay. This finished the building of the Apache.

I then proceded to put no less than 5 coats of grey primer (4 complete; 1 partial) which turned out so nice that I'm not going to pay 5 bucks for a rattle-can of grey; the primer is actually rather nice looking. I then masked off the fin can, antennae section, and a 3/8" strip near the top (for scale details) and painted them silver. Now all I have to do is the little black stripe on the 2429 transition ring, and then the Apache will be ENTIRELY DONE. I feel.... accomplished.

In related news, I used a bit of epoxy to do the last bit of fixing on the Deltie Thunder. It may fly at NERRF.

In unrelated news, there is a reasonable chance that I will attend the OSU-USC football game in the fall. Go Bucks!

Monday, July 20, 2009

40 Years

There are few times that I wish I was old. This is one of them. My only consolation is that I'll get to men and women return to the moon. Because of their bravery and drive, I may be one who goes to the moon someday.

Neil Armstrong, Buzz Aldrin, Michael Collins, and the hundreds of thousands of engineers, scientists, builders, and astronauts who lifted them up, I salute you.

A Mathematician's Lament

Please read this. I beg of you. It's a very good commentary on something that has always bothered me: How math education is a poorly-designed system that seems designed to stifle all intellectually creative impulses.

I try to work around this. I play with graph paper. I prove random equations. I'm teaching myself calculus for fun. I make new shapes. I play with topology. I design rockets. I find patterns. I convert stuff to binary and back. I derive random equations. I teach myself to program. I analyse tic-tac-toe. I factor the time, I sketch, I drop topo maps in 3D and maps from memory. I analyse speech patterns. I go through my textbook to find anything I don't know and won't get taught. I find cool-looking polar equations. I memorize pi. I solve rubix cubes.

I have fun with math.

Math is delicious!

Sunday, July 19, 2009

I'm famous!

Not really. But I do have my picture, amazingly enough in a magazine.

The July/August issue of Sport Rocketry has a 12-page feature on NARCON 2009. On page 20, there's a picture (thanks EMRR) of the vendor new product info session at the beginning of Saturday. I am the skinny guy in the greyish coat under and slightly to the right of the exit sign; you can see only my head and right shoulder.

Other people I can identify:
Gary Tortora (CATO VP and L3 flier) is sitting on the steps in a black shirt in the middle of the picture.
Jim Flis of Fliskits is sitting in the lower-left in the black shirt and cowboy hat.
The green arrows point to Nick of EMRR and his son.
Trip Barber (NAR President) is in the white shirt immediately behind the projector.
Al Gloer (CATO President and NARCON head executioner) is in the red shirt center-frame.
One of the guys from Aerotech, either Dan Michael or Gary Rosenfeld, is leaning against the brick wall to my left.

Let me know if you're in the picture too.

From this post in Nick's blog.

Nike-Apache #5: a slightly smaller post but a full look ahead

Because I didn't have a lot of time to work on it this evening.

I glued the Apache wrap on, and let the two wraps plus the wood glue layer on the MMT dry all day while I was riding roller coasters with mandachan.

When I got home, I used CA on the seams of both wraps and sanded them into niceness. I cut slots into the Nike wrap and sanded said slots; it's ready for fins soon. I drilled four holes in the Apache wrap and inserted and glued the antenna wires. I found the layer of wood glue on the aft end of the MMT to be dried, solid, and very nice-looking (a nice smooth CR-tube joint is a beautiful thing), so I flipped it over and did the same for the forward CR. I also put 2 extra layers of wood glue on the big shoulder of the transition to improve the fit, and one more to increase the strength of the nose cone, especially the tip which is prone to breaking.

Tomorrow will mostly involve epoxy clay - fillets on the CR/tube joints, fillers for the tiny gaps between the Apache fins and the 2429 centering ring / transition, and to hold the 6oz nose weight in the Apache body tube and to glue the nose cone on.

After that, the Apache will be essentially finished - I'll do a little final sanding then prime and paint. It's mostly grey, with some silver near the antennae and the 2429 transition ring is black.

The Nike will have the four fins glued on and filleted, then the launch lugs glued on. Then primer and sanding for it: white for the tube and red and yellow for the fins.

The final steps will involve gluing the transition (painted with the Nike body) to the Apache; application of the three decals, and connection of the two parts with the shock cord and quick-link and the attachment of the chute and protector.

Then flight.

A helpful hint for building 2.6" rockets

Many 2.6" mid-power rockets require you to stand the rocket on end for things like wood glue fillet on motor mounts. Many also have protruding engine tubes and screws that don't allow you to easily stand it on its end.

The answer is a small plastic cup that holds it upright while allowing the protruding parts to fit in the center of the cup. It's a dannon 6oz yougurt cup, and it's 79 cents at the grocery with yogurt included for those building-session munchies.

Machbuster on a G80

I've decided to go for buying a G80-13T for the Machnum Force for reasons:

1) It's more powerful. The G80 has a hair more average thrust and about 30% more impulse, spread out over a longer time period, in the same physical case. It is the single most powerful model rocket engine available*. This means Mach 1.23 versus Mach 1.08, which is a huge difference given that I don't know the Cd of it within a reasonable period, nor do I know the conditions of the launch or the exact margin of stability (more speed = more stable (while subsonic) = safer), and I won't know the weight till it gets checked before putting it on the pad.

2) It's only 3g heavier. That means I don't have to rebalance it.

3) I'd like to use the G78G and its beautiful green propellant in a lower-altitude rocket like the Nike-Apache (after my cert); the G80T has no such nice flame.

4) The G78, as mentioned in a previous post, is missing the forward insulator disk and while the Nike-Apache or Mozzie can probably survive a CATO, the Machnum Force would be utterly destroyed by a CATO at Mach 1.1.

5) I can conveniently buy a G80 at NERRF along with the H128 load for the Nike-Apache.

6) The 7-second delay on the G78, while good for the lighter machbuster I'd originally planned, is far too short for the heavier rocket, which needs the 13-second delay to have a low-speed ejection. The 7-second delay, however, is perfect for a mid-power rocket like the Nike-Apache.

It's gonna be fun. I'll bring this tiny rocket out to the RSO table and he'll ask something like, "Nice little rocket. What're you flying it on, a C6" since that's a reasonable assumption. Handing him a rocket weighting 10oz loaded and saying, "Nope. G80" will be a moment to remember.



* The G69N (38/120) is also a 137 Ns model rocket motor but is 38mm, reloadable, and not nearly as convenient since it doesn't have an ejection charge. The G75J is 155 Ns and under 80N average thrust but has more than 62.5g of propellant. The G104 and G339 are both higher average thrust, but both reloadable and due to their high thrust are high power motors and less impulse than the G80 anyway, plus the G339 has no ejection charge because it's Warp-9 propellant.

The Hunt for 24

A very interesting mathematical diversion found through the xkcd fora. The idea is to take any four numbers, all between 1 and 9, and try to make them add up to 24 using only the four basic operators (+-*/). For example, {1,2,3,4} can use 1*2*3*4=24 or (1+3)*(2+4)=24 or (1+2+3)*4=24 or so on.

{3,3,8,8} is a hard one. Highlight the next few lines for the solution.

8*(3-(8/3))=24

A few like {1,1,1,1} don't have solutions, but I conjecture that they all include at least one and mostly multiple 1s.

interesting article on the subject.

Gonna try and do this

NaBloPoMo: National Blog Posting Month. Basically the idea is that you attempt to post every day for a month. I average slightly over one per day at the moment, but I rarely got a week or more without an off-day, which is averaged out by days with anywhere from 2 to 6 posts.

August is right out as I'll be on vacation for part of the month, but september looks good.

I'll also attempt to do at least one post every day until the 28th or so when I leave for 10 days in Kauai with no posting.

Saturday, July 18, 2009

Nike-Apache #4: Getting there

It's actually starting to resemble a rocket now. I did a bit of work on the Apache, wetting the upper wrap and setting it in place. I'll glue it in tomorrow.

Most of my work, though, was on the Nike fin can.

First, I drew on the line for the fins. On each line, I drilled about 10 7/16" holes with equal spacing, then sanded. Cut in between the holes to form the slots, then sanded. Used the drill to even the slots, then sanded, sanded, and sanded some more, and now I've got 4 perfect slots - much better, straighter, easier, and less tube-damaging than those I did entirely by hand.

Next I took the already-formed wrap, applied a thin layer of wood glue to the fin can section, and glued the wrap on. It's clamped on with rubber bands and scotch tape.

Finally, I inserted the motor mount into the tube. The epoxy clay over the fillets has dried hard and light - perfect. The motor mount fits nice and snug on its own, and I was sure it wouldn't fall, so I applied a layer of wood glue onto the aft CR.

Tomorrow comes wood glue on the forward ring and the inside edges of both, epoxy fillets, cutting slots in the wrap, and starting to glue the fins, which'll then take epoxy fillets of their own. Even so, I'll have used maybe a quarter of the tubs. I like that stuff, although it does smell scarily like Fritos when mixed.

Once the Apache wrap dries, I will glue it on, then drill 4 tiny holes and insert the antennae. After that, all I have to do is glue the weight, nose cone, and Nike transition in place (the latter after painting) and the forward section is done.

The Nike section will require, after the above actions, gluing on the launch lugs and aligning them, then attaching the following via shock cord: Nike body tube / fin can, quick-link, chute protector, chute, and Nike transition / Apache.

The comes primer and probably 3 days of painting involving coats of white, grey, silver, black, and red, then decals. Estimated date of completion: July 25th.

Actual date of completion: July 25th.

Friday, July 17, 2009

Nike-Apache #3: Epoxy and fins!

Got a lot more done. The fin can or the Apache is complete - I cut the fin slots and glued the whole thing together. It's looking pretty good so far, and actually beginning to look like a real rocket.

I got nitrile gloves and got out the epoxy clay. I used maybe a fifth of an ounce for four long fillets on the MMT centering rings, plus a big fillet to hold the retainer rod in place, plus a small fillet holding the screw eye to the transition. Impressive.

I put another coat of wood glue on the transition and nose cone, then sanded. They're ready for primer and paint now.

I'm currently forming the wrap for the Nike body tube. Hopefully its fin slots will be easier to cut than the Apache fin slots.

I also fixed the broken fin on the Deltie Thunder, applied lots of fillets, and another layer of fixing to the broken boom. Hopefully it'll be well enough to fly by NERRF.

I'm off to college-visit MIT and Northeastern tomorrow, then off to an amusement park with Mandachan on saturday, so blogging and building will be a hair light.

Thursday, July 16, 2009

Nike-Apache #2: Starting Building

I finally got the time to start building last night tuesday night. I blame driving class, work, and Omegle for my lack of time.

In roughly pointy-end-to-firey-end order:

Nose cone: Coated with one layer of wood glue as a sealer. Sanded smooth. Pronounced good.

Apache fins: hella work. Sanded a nice knife-edge into the forward end of each as per instructions. Sanded all edges except the root perfectly smooth. Debated trying to shave with the nice knive-edges. Realized that I like all 4.5 hairs on my face too much.

Nike transition: coated with wood glue all over, for sealing on the exposed part and fattening to fit the Nike tube. Inserted and glued the dowel into the upper part for stiffness. (that's what she said?) Inserted and glued the nylon anchor and steel screw eye into the bottom of the transition.

Nike fins: decided there was no way in hell that I could sand full-length knife-edges in all four (1/8" long edges took a total of an hour for the smaller fins). Settled for sanding them flat and smooth with nice smooth edges.

Motor mount: This was most of my work. I sanded the centering rings to fit and glued both on. The second round of wood glue fillets are currently drying; next comes epoxy clay fillets. The forward CR holds the steel shock cord mount. The aft ring holds the threaded rod for motor retention, which is in place but not epoxied in yet. It really gave me the warm fuzzies to when I inserted the 29/180 case and put the retention nut on and everything just fit right.


In other rocket news, I finished the final fillet for the Orbital Transport (it's finally repaired and better than ever) and did a bit of work on the WAC Corporal, including realligning the fins and added nose weight.

Decorum

Just found this webcomic called Decorum.

Some of my favorites:

The crappy plastic forks at my school are just waiting to be relabeled...

I will do this senior year.

...

cute, and again.

Is this solvable? I think so...

Wednesday, July 15, 2009

Driving 4

I'm getting a lot better. I can comfortably drive anywhere here except on the freeway, and even that's getting better. I can drive a lot better on narrower roads and keep my speed much better.

I've also been taking the requisite 30 hours of classroom instruction, which I think is a crock. We basically watch instruction videos from the 80s (with bad disco music) from which i've learned nothing. This is probably because I've been driving much more than most of the other students in the class, though. Like rocketry, tennis or anything else, I maintain knowledge can only be truly atained by being out in the field and putting the practice, well, into practice.

Dicyanoacetylene

Dicyanoacetylene, C4N2, is a pretty neat gas that I happened to find out about on Wikipedia. I was looking at the series of pages explaining orders of magnitude for different things (force, energy, temperature, size, etc) and it was linked to from the temperature page.

  • It has an alternating structure with triple bonds between the central carbon and the cyanide groups; i.e. N≡C-C≡C-C≡N. That alone is pretty cool in my book.

  • It burns at 4990C / 5260K / 9010F; the hottest flame known.

  • It can apparently explode into carbon powder and nitrogen gas.

  • It's a liquid between 21 and 77 C (70 to 170 F) with a density of 0.9g/cc; not too dissimilar from water.

  • It's been found in Titan's atmosphere, and is suspected in interstellar space but hard to prove due to its symmetry, which makes it hard to detect.

  • It's got the IUPAC name of but-2-ynedinitrile. You just can't beat that.


Also, stuff found while doing the research: allotropes of oxygen and solid oxygen.

Marathon

Yes, it really was a marathon. 26.1 miles, a bit more actually, over 3 days.

Day 1, Friday: Got up around 8; had breakfast at our hotel (Woodwards resort). The weather was very good so we decided to climb Mt. Adams. The 3 miles or so below the tree line on the Airline and Valley Way trails went fairly easily; we saw a moose (for the first time on a trail) about 1.5 miles in.
We made treeline about 4000 feet up, with rather nice views to the north. I actually ran out of water (I have a 50-oz Camelbak bladder in my pack) a little above treeline, so we went an extra 0.2 miles to the Madison Springs hut. I was very fortunate that the hut was so close; else I would have had to share with my parents and drink rather less. We reached the summit, which had rather nice views but was very buggy, and started down.
We ate lunch at Thunderstorm Junction, with a huge rock cairn and the Appalachian Trail crossing. We then started down the Lowes Trail, going over a sub-peak called Adams 5 (There's the main peak Adams and the sub-peaks Sam Adams, Quincy Adams, Adams 4, and Adams 5; collectively the Adams Family) and into the treeline.
Unfortunately, the Lowes path below the treeline was wet and slippery; multiple times only my hiking stick saved me from breaking a leg or ankle. The trail that it connected to, the Link trail, was long and very wet. My stomach and left knee were rather painful at the end, but I made 11.5 miles in about 9 hours including a 4500 foot elevation gain, probably the highest in the White Mountains (the trails to Mt. Washington start rather higher than the Appalachia lot for Adams).

Day 2, Saturday: We felt rather better when we got up and decided to do Mt. Eisenhower (4761') via the Edmands path. It starts at about 2000' and comes out of the treeline 2.9 miles and 2000' of elevation higher. The trail was easy, not too steep, and not too wet, plus around 3800' there are nice views through the trees to the north and a few small waterfalls. It comes out onto the Crawford path on a small col with great views and we ate lunch there. The last climb to the summit was easy and quick. We went down the other side of the peak and around the east side for a 1.2 mile loop, then back down the Edmands path, for 7.0 miles total.

Day 3, Sunday: I was pretty sore from saturday and literally rolled out of the car. We only intended to go halfway up Mt. Chocorua to the Champney Falls, which I had a grand time exploring and climbing, but we decided to go for the top anyway. It was an easy trip to the top, and the views from the bald summit were amazing. 7.7 miles round trip.

The total for the 3 days was 26.6 miles - almost exactly the length of a marathon. We plan to come back next year and hike Mt Jefferson (third highest in New England; we've already done Adams and Washington, the top two) via the tricky but short Caps of the Ridge trail.

Monday, July 13, 2009

Okay, Okay, fine.

I'll use Nike-Apache from now on. 2-1 wins the poll.

Apogee and Cosmodrome (sell and make the kit) use Nike Apache; so does Wikipedia and most results on google. Rockets of the World 4th edition uses Nike-Apache and hyphenates all other multi-stage sounding rockets with Nike boosters.

Here is a nice two-stage conversion with electronic staging for a smaller Estes Nike-Apache which the author notes was upscaled into a 1/5 scale version somewhat larger than my 1/6 kit.

Thursday, July 9, 2009

In New Hampshire

Our hotel has free, and fast, wifi here, so I'm be able to update at least a bit.

I actually got quite a bit done on my simulation programming today.

Second, I fixed the staging algorithms, which took a lot of work, but now there's four separate stages possible: single stage, lower booster stage, middle booster stage (can have more than one per rocket), and sustainer. Much of the work for this was concentrated on three points. First, finding and implementing a variable for the stages that wasn't already used; second, findign which variables to zero for each stage, and three, telling the main calculating loop when to got to the next stage, as well as fixing a nasty altitude-calculation bug.

I also fixed a bug which prevented me from doing more than one sim at a time, and now I'm working on allowing custom motor files to be created in-program to allow sims of cluster rockets.

I also discovered a flash version of Portal for those of us without big video game systems. Solutions are available on Youtube.

Good night.

Vacation

As far as I know, this'll be my last post before going on vacation. It'll put me below my post-a-day target by the time I get back, but that's tolerable since I'll have hiking and the Nike Apache to blog about.

Also, a new poll: do you prefer Nike Apache or Nike-Apache?

Current fleet

6mm (6)
Gnat **
Pen rocket
RNGbane the Valkyrie
IT
Crayon **
Hummingbird

13mm (11)
Jinx
13mm Saucer
Cohete
SpaceBusII
Mosquito*
Electric Mosquito
Rokit *
mandachan! *****
Gauchito
WAC Corporal
SpaceShipTwo **

18mm (21)
Nuclear Mosquito
Astron Invader
Scissor-wing Transport
Transwing
Glider II
Cosmic Cobra
Alexi Leonov *****
Frankenstein II **
GBU-24 Paveway III
Astrocam
Wizard
Rama
Screaming Yellow Zonker!
Mongoose *****
Orbital Transport*
Cloud Hopper
Pigasus
Mach My Day
Bullpup
SpaceShipOne
18mm saucer

24mm (6)
Vampire ***
Nantucket Sound
Lord Gavin **
Deltie Thunder *
Comanche-3 *****
24mm Saucer

29mm (3)
Machnum Force **
Mozzie
Nike Apache ****

Total: 47 rockets. Since my last update, I have added 1 6mm rocket (the Gnat), retired the 13mm monocopter, added 2 13mm rockets (Electric Mosquito and SS2), retired the 18mm monocopter, and added the 29mm Machnum Force and Nike Apache. This represents 2 retired and 5 added for an increase of 3 rockets.

* currently under repairs (4)
** built but not flown (6)
*** booster only (1)
**** currently being built (1)
***** includes both booster and sustainer (4)

My current plans after the Nike Apache are few. I'd like a 29mm saucer (G75J at CATO hell yeah) and an 18mm booster to replace the destroyed Hi, but that's about it.

Wednesday, July 8, 2009

Nike Apache #1: Parts list

It finally arrived today. It took 10 days, which is longer than usual but I blame it on the large package and 4th of July holiday.

I intend not just to build it to the level that I do other kits, but to build it well. That means built strong, with epoxy fillets and the strength to survive the kick of up to an I200 (the most powerful Aerotech 29mm motor available). That also means everything sanded, primed, and painted well with good masking. I've got primer, steel wool, sandpaper, and 'frog tape'. Now i just gotta put the damn thing together...

Just for reference, the Apache is the top section and the Nike is the thicker lower section.

The contents:

  • 1950s style face card, with a line drawing of the rocket and its vital stats. It's 52" long, just over a pound, and 2.6" in diameter.

  • Conical balsa nose cone; 6" long and 1" in diameter.

  • 5oz lead nose weight; 1" long and 1" wide.

  • 24mm thick-wall tube 22.5" long; forms the Apache body.

  • 2 4.85" pieces of 1/16" wire; to be bent to make 2 antennae.

  • 24/29 centering ring, 3/4" long. To be sanded into a curve for the transistion from the Apache fin can to the rest of the Apache.

  • 29mm thick-wall tube 3.55" long; forms Apache fin can.

  • 24/29 centering ring 1/4" long; goes right behind Apache fin can.

  • 4 Apache fins. 1/8" 5-ply wood, with a tight grain that'll only need one sanding and no filling.

  • 11 feet of 3/16" tubular elastic shock cord. I like the look of a rocket dangling far beneath its chute, which also helps with recovery from trees, and that long shock cord is good.

  • 3/8" dowel 2 5/8" long, to be inserted into the transition for strength.

  • Balsa transition. Epic. It's the famous Nike transition, which bumps a bit out from the Nike booster then goes waaay in to the sustainer. It's a solid piece of balsa the size of a soda can. It's almost 6" long total and 2.7" wide at its maximum, with 2.8" of length outside the rocket. It's also where the rocket splits in two for recovery.

  • 1" plastic screw-in anchor, for anchoring the screw eye in the bottom of the transition.

  • 1/2" screw eye to attach to the transition.

  • 1.5" long quick-link for attaching the elastic shock cord to the steel mount.

  • 14" long shock cord anchor of 1/8" steel wire. It attaches to the forward centering ring for an indestructable, heatproof mount.

  • Nike body tube. 2.6" wide heavy-wall tube 21.2" long.

  • 2 sections of 1/4" launch lug each 1" long.

  • 2 sections of balsa 1" x 1/4" x 3/8"; for use as lug standoffs to avoid the bump in the transition and prevent the rod from scratching the paint.

  • 1 29mm thick-wall motor mount tube 7.5" long. It only just fits a 29/180 case, but I feel that the mount is strong enough to handle the 240Ns and 360ns cases as well, plus of course the smaller 29mm and 24mm cases.

  • 4 Nike fins. same quality as before and also TTW; these require a labor-intensive knife-edge sanding.

  • Forward centering ring. 1/8" ply as above; has 2 holes to fit the loop on the steel cord.

  • Aft CR. same as above, except with one 1/4" hole.

  • 3/16" threaded rod 2.8" long for motor retention.

  • Spacer for said rod.

  • Washer for said retention system.

  • Nut for said retention system.

  • Paper wrap for forward section of Apache body tube.

  • Paper wrap for Nike fin can.

  • 28" red circular nylon chute.

  • Nike decal sheet.

  • Apache decal sheet.


That's 38 items of 31 types. That's a lot of parts for the money.

Next step: building the motor mount and Nike fin can.

Pictures coming soon.

All of this will eventually get placed into an EMRR review. It's important enough that it gets its own label on my blog, separate from 'certification' even.

Getting a bit done...

On the Orbital Transport:
I got the strake cut out, and the wing and strake glued on. The first of two fillets is drying. It'll be back to working order, though not painted, by when I leave on thursday.

At blogging: the last post was my 400th post.

Tuesday, July 7, 2009

Update 3/3

Electronics

I'm getting a bit back into electronics after learning to solder. I plan to solder a 5V regulator circuit based on the 7805 soon.

I desoldered a number of components last night, including about a dozen 5-band (precision) resistors, several diodes that I don't recognize, and a 2-channel integrated amplifier in a 7-pin TO-220 package.

More later. I'm tired and I need to sleeeeep....

Update 2/3 is Installing

This one is rocketry.

1) My package still hasn't come yet. Hopefully tomorrow, if not then wednesday. Its statis still hasn't changed since being in Denver last Tuesday.

2) Stuff I've got to do #1: Fix the Mosquito. It needs a new body tube, then a new paint job, to replace the coloring I did previously with Sharpies.

3) Stuff I've got to do #2: Fix the Orbital Transport. It needs a new strake, which I can make out of a spare piece of 3/16" balsa. I printed out the patterns from JimZ's site yesterday. Then, I'll glue the strake to the main wing assembly, then reglue the wing to the body, and finish the fillets. I didn't put the fillets on the original, but they should make it much stronger. I may or may not paint it.

4) I've posted a request for information about potential payloads for the Nike Apache on the xkcd fora. Feel free to read it and comment.

Update 1/3 is installing. Do not power down or unplug your machine.

Not gone this time, just kinda didn't have much to blog about for a few days. Now I do, and everything will be divided by topics. This post: everyhting that doesn't have a topic.

1)UGA... CAU GCU AUG AUG GAA CGU ACU AUC AUG GAG! Go find an RNA codon table, then come back and laugh at me.

2) I'll be off hiking in New Hampshire from thursday night till sometime sunday. That means not much internet access. I will likely not be able to blog during that time. I also won't be able to do much with rocketry or electronics at that time. I might do some programming or scale model prep / design in the car, but that's about it. Instead, I will be spending time in the alpine zone above the treeline, where you can see for a long way, and the air is fresh and cool, and where you can see lots of stars at night. I will recap, of course.

3) I have discovered the Arcade Fire and Neon Bible. Epic. Via youtube, I have also discovered the Katamari Damacy song, and why the Animal Collective really does sound like a bunch of squirrels on acid.

4) A few of my low-work experiments are going well. My salt is almost 3/4 through drying up, and the carbon rod I inserted has some nice cubic crystals. The bolt head I put in some water is producing an immense amoutn of rust. The biology experiment I referenced a while back is also going back.

5) 'Intervention' is pure unmitigated awesome.

Friday, July 3, 2009

Strange conversions

From this part of the xkcd fora:

note that if you measure distance in seconds velocity becomes dimensionless. In particular you could put c = 1. All velocities would then be measured as fractions of c.

The idea is similar to lightseconds but not the same, since lightseconds is actually a unit of length, whereas here we have introduced a system of units in which any dimensionfull quantity can be expressed as any other one (if we also have h = G = 1). That is we can express mass as a certain multiple of an inverse meter, or second. So mass is really the same as a frequency. And of course in this system all our usual units correspond to particular dimensionfull quantities: one meter, one second, etc. And thus they can be expressed in terms of each other.


I never though of this before. Basically, if you express distance in seconds, or any other unit of time, then velocity, which equals distance over time, has seconds as the unit on both the top and bottom of the equation, and is thus dimensionless. Thus, you could express velocity as a simple number, say, 0.2 (i.e, 0.2c or about 60,000 km/s), rather than including units.

A similar idea is used with transonic speeds; Mach number, a dimensionless quantity, is used rather than a unit-ed velocity.

In the above syste, there's other weird stuff: mass is in units of m-1 or s-1, and can even be expressed as a frequency.

Thank you to Certhas, whoever you are.

Thursday, July 2, 2009

About my order

I made the first of 4 orders of Sunday. I've got my debit card now so I can make the rest of them on my own and on my own time, but I needed to make this one so I can have it build and painted by August 14th, especially with a 4-day hiking trip and 8 days in Hawaii with the family taking lots of time.

First, of course, is the Nike Apache. I'm really excited about the kit and I think I'll have a lot of fun building and flying it. It'll fly on anything from E15s to I200s; I'll use an H128W for the first flight - my cert flight - and mainly Es thru Gs afterwards.

I also ordered a Madcow 9"x9" Kevlar chute protector. With a nylon chute, steel anchor, and steel quick-links, that's probably overkill, but with the larger motors it'll be good protection from shotgun ejection charges.

The quarter-pound tubs of epoxy clay will come in real handy, I imagine. Doing fin fillets, holding in the bolt to the transition section base, placing the rail buttons, fixing my old rubix cube, etc etc etc.

Those were the three things I need for my cert flight; I also bought a few things for other rocketry fun. I bought a D21-4 to give some fat or heavy 18mm rocket a kick. Right now, I'm leaning towards either Rama or SpaceShipOne; possibly the Cosmic Cobra.

4 29-to-24mm centering rings, mainly for a second 29/24 adapter that better fits reload casings and F32s.

Finally, I bought 10 feet of Kevlar string. 1/10" diameter yellow kevlar; 300 lbs test strength. Mainly so I've got better material than elastic for future mid-power rockets.

The total was about 106 dollars, but that's not bad for a high-quality MPR kit plus one motor, 6 parts, epoxy, and shipping for a rather large box.

I'm Ba-ack!

Back from engineering camp. It was good, although I was disappointed that there was nothing about aerospace or aeronautical engineering included. I learned to solder and I actually did pretty well. I made an electronic die from a kit, then promptly discovered that it is biased towards 2s and 3s. (The 4024 counter has 8 states of the last 3 bits, but only 6 numbers on the die, so 2 and 3 get doubled.)

I was comprehensively beaten by at least a dozen people at pool. I did win a lot too, though; about half a dozen clean wins and the same amount from my opponent pocketing the 8-ball or scratching on the 8-ball.

Saw some pretty cool stuff. UConn has a complete fabrication lab, where they can make transistors, LEDs, solar panels, and even smaller VLSI chips. They have an advanced software program, which was given to them at a huge discount (it's normally one hundred thousand dollars PER COMPUTER), where they can design chips with thousands of transistors. They have modern equipment and cool experiments - it's a research school - going all over. They convert their own cooking oil to biodiesel to run their busses. They also have HUGE incoming pipes. I have never been on internet so fast.

We saw a few cool demonstrations this morning. One was the Briggs-Rauscher reaction, where a reaction cycles from clear to blue and back, on about a 15-second period, for almost 50 cycles; another was the Ruben's tube. The thermite demonstration, unfortunately, failed to work.

I had some pretty good times solving my 5x5x5 Rubik cube as a 5x5x5, and some decent times solving it as a 3x3. A number of people were rather impressed. Last night, I accidentally knocked ou an internal piece (many are free-floating) while solving it, but nothing was damaged and Youtube provided the solution.