1/2A3-0T

I'd like to launch the mandachan, which is a 13mm minimum-diameter rocket, with two staged motors. Unfortunately, there are no currently produced 13mm (or smaller) booster motors, and the promised Estes A10-0T is nowhere in sight. So, I took a 1/2A3-4T motor, of which I have several, and modified it. I used a sharpened screwdriver to pick off the clay cap, which I will prolly discard, and the ejection charge, which I will keep. Both of those were loose-grained and came out almost immediately.

However, the delay grain was much different. It was almost 3/8" of densely packed material that took almost 20 minutes of scraping to get it all out. However, I managed to get all the way down to the top of the blackpowder grain. It's effectively now a 1/2A3-0T.

Dead Tree Edition #2

I just finished the rough draft of my junior History thesis paper, nominally 5-7 pages.

Mine:
9 full pages plus 2 lines, 12 font doubled-spaced
14726 characters
2924 words: exactly the same as last year's Dead tree edition
95 sentences in 11 paragraphs
4.8 characters per word
30.7 words per sentence
8.6 sentences per paragraph

I expect near 10 full pages in the final draft. It's an argument that the attack on Pearl Harbor was actually a military failure for the Japanese. I'll post the final draft text eventually.

Repairs

The foam transition section on the Great Pumpkin is being glued back into place.

Glider #2 has a new tail fin.

Glider #3 has its glider hook reglued.

The glider boost pod has its bent tube stiffened and repaired.

The Screaming Yellow Zonker has a new spin fin and a second spin tab that are currently gluing into place. The second spin tab will allow spectacular spinning flights on As and Bs as well as Cs.

Launch Report 135: CATO 155

Today was an excellent launch day. 60-degree temperatures, little wind, a clear field and sky, and my dad, a friend, and mandachan were all there to watch.

First came the gliders on a B6-2. One glider (#3) had its hook broken off at ignition, and it didn't make it off the bad, but the other (#2), hung on all the way to ejection at around 500 feet. It glided for well over a minute, prolly closer to 2, before hitting the trees. It bounced down 80 feet of trees to the ground, amazingly losing only the tail fin. Both gliders will fly again.

Second came the Mozzie on an E23-8T. I drilled the delay out to 5 seconds, but it was still 8 seconds from burnout to ejection. It boosted fast and smooth to around 650 feet and ejected at about 500, recovering with no damage. Es are a good fit for the Mozzie.

Third was the Screaming Yellow Zonker! It had a cool sound and nice spiral smoke trail. It recovered right near the pad, mysteriously missing one fin, which I'll replace.

Fourth was the Great Pumpkin on a G53-5FJ. The Fast Black Jack (aka Black Max) motor ignited instantly and it boosted fast and straight. The 'punkin' inflated its chute instantly and it drifted off into the distance, remaining in sight for 2 minutes and 33 seconds. The main body of the rocket did not deploy its chute and the foam transition broke a bit; it should be easy to repair.

Fifth was the Twofer on a pair of A10-3T motors. Despite aspersions cast by other fliers, it boosted fast and straight with a just a tiny bit of spiraling.

Sixth was my 29mm pyramid on a G71-4R Redline. It was my third flight of the day on my new 29/40-120 case, which I now really like. It flew perfectly straight to about 300 feet. The delay was long and ejection was simulataneous with impact, but it was amaingly undamaged. The light ply and wood glue held.

I flew 6 rockets on 7 motors today, including 2 G and 1 E motor, which makes it my second-highest day in terms of impulse flown, next to NERRF 5 where I flew 1 F, 1 G, and 2 H motors.

Total since September 29, 2008: 1752 Ns (36.9% K motor).

Mandachan took some awesome photos; I'll post them soon.

Modifying Aerotech Delays

I bought an E23-8T on a whim, because it was 6 bucks, a pretty good price for a single E motor. Unfortunately, the 8-second delay is not very good for any of the 29mm rockets I have.

However, Aerotech has a very helpful way of changing that. On the excellent Resources tab of their website, I found a document that tells how to drill out their delays for shorter delay times. Simply take a 3/16" drill bit, and by hand drill out 0.024" to 0.031" per second of delay - just over 1/32" per second. The drilled-out section then faces the ejection charge in the final assembly.

Interestingly, they also state that the delay scraps should be electrically ignited safely outdoors for disposal, rather than simply put in the trash. I plan to test this with either a G53-7FJ or E23-8T on Saturday.

Progress

My computer should be back tomorrow. Maybe. Hopefully.

The Nike Goon is functionally finished. The white, red, and yellow paint job came out perfect; now all it needs is 'United States' painted in black down the side.

The Great Pumpkin is also finished. I used a chunk of epoxy clay to glue on the shock cord, and then glued on the forward section with wood glue. I put 2 1/4" launch lugs on balsa standoffs, and it was completed. I spray painted it freeform, without masking, so the color blended together. The upper section is black, and the lower section a mottling of yellow and red. Looks pretty nice, actually.

Planned flights for Saturday follow. Several motors are listed for a few that I'm not sure what motor I'll use with.

10" Pyramid: G71-4R: ~200ft
Mozzie: E18-4W: 785ft; E23-5T*: 655ft
Nike-Apache: E18-4W: 403ft; E23-3T*: 321ft; F23-4FJ: 508ft; F32-4T: 667ft; G53-7FJ: 1113 ft
Great Pumpkin (10oz rocket + 10 oz pumpkin and chute): F32-4T: 485ft; G53-4FJ*: 748ft

* drilled delays. See next post.

Twofer: 2xA10-3T: 513ft
Nike Goon: B6-4: 350ft; C6-5: 650ft
Glider (2+3)**: B6-2: 300ft
mandachan!: A10-3T: 500ft
Screaming Yellow Zonker: C6-5: 1000ft
Astron Invader: B6-2: who knows! It'll loop, that's for sure!

** Gliders #2 and #3 on a single boost pod

Building updates again, because I do nothing else

The Nike Apache is almost completely finished. All four fins are filleted, as is the launch lug, and the last fillet on the motor mount is drying. I'll put a coat of primer and maybe one of white on tomorrow, then red and yellow for the fins on tuesday, assuming it doesn't rain any more. It'll fly on saturday at CATO 155 on either a B6-4, or a C6-5 if it's not windy.

The Great Pumpkin is also coming along well. All four through-the-wall fins are glued to the motor mount and filleted, and the motor mount is glued into the body tube, with the final glue joint drying. I put the baffle in, captive but not glued in place, and then glued in a 2" ring with a 1" hole about 6" from the top. This lets the baffle also serve as a piston to further protect the parachutes from the ejection charge.

The nose section / payload compartment is also nearing completion. The protective glue layer on the foam transition is dry, and the compartment is currently gluing to the transition. I just need to make the nosecone and glue the 'pointy end' to the 'firey end', and it's practically finished and ready for painting (orange and black, of course!).

Building Update

My computer is, of course, still out of comission, but I'm able to use my parents' computer a bit.

I've gotten quite a bit done on the Nike Goon and Great Pumpkin over the last few days. The Great Pumpkin has most of its subassemblies ready to assemble. The motor mount is glued together (except for possibly a kevlar shock cord) and and the fins (1/8" balsa) are cut out, although I still need to sand them and cut the TTW (through the wall) tabs, which will anchor them to the motor mount. I've coated the entire foam transition piece with wood glue, which'll give it strength, make it easier to finish, and lessen the chance of it getting dented or crushed. I still need to create the pattern for the single-use paper cones that'll serve as the nose cone.

The Nike Goon is also coming along well. I cut the fins out last night, coated then with wood glue for strength and to aid finishing, and glued them on today with superglue. The motor mount is glued in, and it and the fins are getting wood glue fillets for strength. I intend to be able to fly it on anything from an A8-3 to a D21-7T. I also glued the shock cord in; after the fillets dry, i'll be all ready for the paint scheme of white body and nose cone with 3 red fins and 1 yellow.

Also, the Buckeyes won today, 27-24, in overtime. Over UNDEFEATED Iowa. They're now Big Ten Champions and headed to the Rose Bowl. Go Bucks!

Just checking in

It'll be a few days before my computer is back in operation. Till then posting will be light but building will be much. The Great Pumpkin is coming along well.

Well, this sucks.

My computer got a virus last night. It seems to have managed to disable Norton Antivirus, which is one of the best antivirus programs out there. My computer is in capable hands, though, and most of my data is backed up. However, I won't be blogging much for a while; this post is from the local library which I'm at for a few minutes today. Hopefully it'll be fixed in time for CATO 155 next saturday.