Monday, November 30, 2009

More Mach Goon Building

I cut a 3' length of 1/8" kevlar for the shock cord and tied it to the eyebolt; I then put a few drops of CA on to keep the knot from unraveling.

I glued the motor tube into the body tube with wood glue, and the first fin is now drying. It'll take prolly the rest of the week to glue on the other 5 fins and double-fillet them, but the work should allow the cheapo clementine-box fins to withstand the forces of 850 mph. I'll also layer wood glue on the body tube and nose cone at the end of building; it'll add a tenth of an ounce or two, but add significant strength to the body tube.

Here's a picture of the parts, taken before the last round of gluing:















I checked on TRF and it appears to be allowable per CTI instruction sheets to remove part of the ejection charge.

Also, I am now using gmail in the 'ninja' theme. I may never go back.

Sunday, November 29, 2009

Mach Goon building

I finally got some time today to work on the Mach Goon.

First came the fins. I cut six identical fins out of 1/8" light plywood from a clementine box. They're 2.7" wide, with a 3" chord on the root and 1.5" on the tip. I filled holes in two of them, and they're currently drying from a coating of wood glue. I may add paper skins for strength as well.

I ran a few CP calculations of the Mach Goon that turned out pretty well. I really only need 4 fins to keep it stable, but I'll probably add 6 just to ensure stability, even if a fin or two snaps off from the stresses of flight.

Next came the nose cone. I cut off the attachment loop and much of the shoulder, leaving just enough to keep it firmly in the body tube. I added a bit of weight to the front of the nose cone, and I'll probably add some lead shot eventually to keep in stable.

I decided that the two 48" by 1" streamers that I recently bought, plus perhaps one more, should be perfect for bringing it down safely yet quickly, with minimal drift. The rocket itself will weigh no more than 3 ounces, and the Pro38-1G case just a few ounces more. if absolutely needed I'll get a bigger streamer, or use a very small parachute.

Finally, I cut the motor tube. I wound some masking tape around the 38mm LOC Precision kraft paper tube, and cut it to length (6") with a small x-acto saw. I marked off 1/2" from the factory-cut end, cut just a little bit, and then unwound the outer 4 layers from the other side. It now fits perfectly inside the BT-60 of the Baby Bertha tube. The 1/2" that sticks out will the the attachment point for the masking tape to hold the motor in. This rocket will have to withstand a full 38mm ejection charge unless I can modify the reload, which is not as easy with CTI loads.

Saturday, November 28, 2009

Thoughts on the Mach Goon

I've finally gotten to the point where I'll actually be building the Mach Goon soon. Most of the design is settled; however, there are still 2 things I need to figure out.

First and foremost is motor size. I have 4 options: Cesaroni Pro38-1G or 2G, or AT 38/120 or /240. Simulations using a variety of motors are below; Cesaroni motor data is estimated and not exact. Parameters: 3oz, 1.65" diameter, Cd = 0.6.
SU | G80T: 3066 ft, Mach 1.11. (137 Ns)
38/120 | G61W: 3276 ft, Mach 0.88. (120 Ns)
38/120 | G67R: 2985 ft, Mach 0.85. (110 Ns)
38/120 | G69N: 3486 ft, Mach 1.02. (137 Ns)
38/120 | G339N: 2959 ft, Mach 1.29. (110 Ns)
38/240 | H123W: 5256 ft, Mach 1.30. (230 Ns)
38/240 | H148R: 4368 ft, Mach 1.27. (220 Ns)
38/240 | H242T: 4554 ft, Mach 1.62. (230 Ns)
38/240 | H669N: 3790 ft, Mach 1.72. (220 Ns)
Pro38-1G | G115WT: 3401 ft, Mach 1.15. (141 Ns)
Pro38-1G | G185VM: 2908 ft, Mach 1.19. (128 Ns)
Pro38-2G | H152BS: 4813 ft, Mach 1.45. (279 Ns)
Pro38-2G | H400VM: 4327 ft, Mach 1.93. (255 Ns)

Several things are clearly obvious. First, the 38/120 case is right out - the only 2 motors in it that break Mach are Warp-Nine reloads, which I can't use because they can't have delay grains or ejection charges, and there's no room for a timer.

Second, that most of the two-grain reloads - AT 38/240 and CTI Pro38-2G - would not be good, because many of them would be pushing Mach 1.5, and a few even get past 2000 fps. At those speeds, there's no way I could ever manage to hold fins on without an absolutely perfect epoxy job. Hence, the best choice will be the Cesaroni Pro38-1G case with a G115 White Thunder or G185 Vmax reload. The G115 was the advantages of being far easier to track and offering slightly gentler acceleration; the G185 brings higher speed and a lower altitude - within reason, even - to recover from.

Third, note that a 29mm G motor can, theoretically, break the sound barrier. However, an complete Aerotech 29/120 case is actually more expensive than a 38/120 casing, as is a CTI Pro29-2G system including the rear closure, which is not needed on their 38mm reloads. The G80 is then within reason, but I'd prefer the 1G case since, if I do get it back, then I can fly G69 sparkies in it!


The second issue, the fins, I'll deal with later today.


Motor data from Thrustcurve.

Massive Price Sheet

After a few hours of work, I've compiled a massive price list of almost everything imaginable related to rocketry. I've got Quest MMX motors, every motor type sold by Estes, every Aerotech single-use motor (except the mysterious I350R-10 and K250W-P, which no-one seems to sell), all Aerotech / RouseTech reload cases and AT reloads sizes 18mm-38mm (except the 24/20-40 and 32/60-100 RC glider cases, which again are evry very rare), all Cesaroni Pro29 and Pro38 cases and reloads, and a small avriety of igniters, etc.

It works out to approximately 159 items - that's 1431 cells, of which approximately 800 are filled with prices, and 600 are not a valid product - vendor combination.

The vendors are:

Apogee Components
Balsa Machining Service
Discount Rocketry
Giant Leap Rocketry
Hangar 11
Hobbylinc
Red Arrow Hobbies
What's Up Hobbies
Wildman


I plan to add more soon - AT and CTI motors up to 98mm, the Aerotech RC motors, Quest BP motors, and perhaps other reloadable motor systems like Kosdon, Loki, AMW, Gorilla, etc.

I'll post it for all to see on Google Documents eventually, but if anyone wants a copy now, drop me a line - my emails are found on the link at the very bottom of the page.

Friday, November 27, 2009

Watching Goldeneye

Means you get the real post in a few minutes.

Thursday, November 26, 2009

Thanksgiving

I'm off to the cousins to eat delicious turkey and pie. I'll be back tomorrow.

Wednesday, November 25, 2009

Black Paint is my Friend

I got a lot done tonight with nothing more than a little bottle of black paint:

-- Painted the new fin and spin tabs on the Screaming Yellow Zonker, plus went over a few areas to make the entire fin can a nice monochrome black. Looks very nice.

--Painted the Great Pumpkin's nose shroud black, as well as covering up the glue lines on the foam transition from the repairs.

-- Touched up the nose cone of the glider pod, and the fins on the Odyssey.

I also glued the baffle in place in the Great Pumpkin, so it'll act more as a baffle and not a blockage.

Tuesday, November 24, 2009

Remembering Matty B.

This afternoon, Matt Buriak, a junior in my school class and a friend to all, passed away. He suffered an aneurysm on Saturday and despite the best efforts of the best local and state doctors, he fell into a irrecoverable coma. Matt was an organ donor, and at least 3 others' lives will be saved and improved thanks to him. Matty B, we will remember you forever.

CATO 155 pictures #3

This series of three pictures is all of my 29mm pyramid lifting off on a G71-4 Redline. They were taken by mandachan on a camera set to burst mode at 3.5 pictures per second (~0.29 seconds between frames). Even though the motor chuffed, she managed to nicely capture it.

Chuffing at ignition:
 

Under full power; note the red flames reflected in the bottom of the pyramid.
 

The smoke trail.
 

Once again, the awesome pictures are courtesy of the wonderful mandachan.

Previous pictures here and here; launch report here


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CATO 155 Pictures #2

First off is a historic flight... Al Gloer getting off the pad first!

His and the other rocket (on the right, which took off a second later) are both PemTech King Krakens flying on Cesaroni G69SK sparkies.
 

Here is the Great Pumpkin, my 4" diameter pumpkin lofter, sitting boringly on the pad:
 

And igniting the G53-5FJ motor. It's not actually on the closer LPR pads, but on the mid-power pads directly behind but further away.
 

And under full power:
 

Once again, the awesome pictures are courtesy of the wonderful mandachan.

Previous pictures here; launch report here

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LHS Jazz Band at MGM Grand

A while ago I got a request for videos of my high school jazz band. Here are four videos of us playing at MGM Grand at Foxwoods:

Short Skirt | Long Jacket (Cake)

Spinning Wheel (Blood, Sweat, and Tears)

Fantasy (Earth, Wind, and Fire)

And our signature song, Frankenstein (Edgar Winter band)

I'm the shorter of the two trumpets, between the bass and the rest of the brass section. Enjoy!

CATO 155 Pictures #1

Presenting: the flight of the Mozzie, as captured by my dad.

At the moment of ignition of the E23-8T:
 

Liftoff:
 

Way up in the sky, near apogee at ~700 feet. This one was darkened in Picasa to see make the smoke trail visible and enhance the clouds:
 

Coming down under the parachute; click to embiggen and to see the Mozzie in the center of the frame.
 
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Monday, November 23, 2009

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.

Sunday, November 22, 2009

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.

Saturday, November 21, 2009

Launch Report #35: 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.

Friday, November 20, 2009

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

Sunday, November 15, 2009

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!).

Saturday, November 14, 2009

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!

Friday, November 13, 2009

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.

Thursday, November 12, 2009

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.

Tuesday, November 10, 2009

Some actual building!

Amazing, I know.

Most of the work was on the Great Pumpkin - my pumpkin lofter for the November 'Pumpkin Chunkin' contest at CATO. It'll be 4" maximum diameter and about 30" long when finished.

I knew I needed a 4" payload bay for the pumpkin, but I only had 3" tubing, so I cut a 6" length, cut a slit, and glued another piece across the opening to form a 6" piece of 4" tube. I've also glued on a few other bits for reinforcement.

I found an old foam cone, and got permission from my mom to cut it up. I cut a 2" core out with a hole saw, and it now will form a nice solid transition from the 4" payload section to the 2" main body tube. It's currently gluing to a 4" plywood ring, which I cut out with a handsaw.

For the motor mount tube, I cut a 6.5" section of 29mm tube. I took two 1/4" thick plywood rings, drilled a 1" center hole with a spade bit, and then used a dremel tool to extend the hole to 32mm for the 29mm motor mount tube (which is 32mm outside diameter). The aft ring is currently gluing to the tube with wood glue.

I also started work on one of the Baby Berthas, which'll become the Nike Goon. I assembled the motor mount and modified the nose cone so that the streamer can fit inside, plus I put a little clay in the tip of the nose cone for stability.

I'll cut the fins tomorrow. They'll have TTW (through the wall) tabs that attach to the motor mount, and they'll be scale-sized Nike fins - exactly 1/10 the original size. That is; 2.34" root edge, 1.21" tip, and 2.16" wide. The original Nike boosters were 16.5" in diameter - exactly 10 times the 1.65" of the BT-60 of the Baby Bertha.

(Thank you Rockets of the World)

Monday, November 9, 2009

Up Late Again

I was up till nearly 2 doing homework last night, and I've still got a section outline for history and 5 calculus problems to do tonight. Wednesday will be a nice break - we have it off for Veteran's Day.

I got my order of rocketry stuff in the mail today. I ordered in last Wednesday night, so it took under 5 days. Very impressive, epecially since it was sent from Georgia, by snail mail.

The 38mm tubing is great - I'll only have to peel off one layer to get it to fit into the Baby Bertha.

See you tomorrow.

Sunday, November 8, 2009

More new motors from Aerotech and Cesaroni!

Today, Cesaroni announced the certification of 11 new reloads - 1 G, 1 I, 1 L, 6 M, and 3 N. These included two new propellants: C-star and Pink. C* is the characteristic velocity of a rocket motor, and accordingly C-star is a high-performance propellant with high metals content. The Pink propellant (some call it violet) was originally put forth by Paul Robinson. It's mostly a one-shot deal, for a woman certifying L3 on a bright pink rocket, but more will be certifed if the demand is there. It looks like this:


The certified motors were:
93Ns G80-SK-14A (CTI Pro29-2G) Skidmark
502Ns I120-IM-15A (CTI Pro54-1G) Imax
6118Ns M3100-WT-P (CTI Pro75-5G) White Thunder
6162Ns M1675-PK-P (CTI Pro75-5G) Pink (pictured above)
7545Ns M1590-CL-P (CTI Pro75-6G) Classic
5472Ns M2250-CS-P (CTI Pro75-4G) C-star
5342Ns M1560-WT-P (CTI Pro98-2G) White Thunder
9994Ns M3400-WT-P (CTI Pro98-4G) White Thunder
17631Ns N3800-BS-P (CTI Pro98-6GXL) Blue Streak
20146Ns N5800-CS-P (CTI Pro98-6GXL) C-Star
4701Ns L1290-SK-P (AMW 76-6000) Skidmark

I'm especially excited about the G80SK - the first MPR skidmark ever, and it's got under 62.5g of propellant (The 38-1G G69SK skid has 67g of propellant). It might be enough to get me to buy a CTI Pro29-2G case.

Full story on Rocketry Planet.

Not to be outdone, Aerotech is working on some new stuff of their own. There's the Loudmouth - looks like a White Lightning, sounds like a Sparky. A K345LM was flown at Plaster Blaster this weekend, as were a K375NW (Boost-sustain), J320WS (Super White Lightning), and the J99N endburner. Interestingly, the Loudmouth might 'possibly' make it to mid power. From Dick Stafford.

Saturday, November 7, 2009

Darn it

Internet out at my house = 3 months of posts every day broken. Oh well.

Thursday, November 5, 2009

Too much stuff

So you don't get a proper post. Because I have calculus and band homework, not to mention that I had work and jazz band tonight. I think we're the only jazz band for a while around that plays stuff like Stairway to Heaven and Enter Sandman.

Wednesday, November 4, 2009

Baffle

What I'm building for my pumpkin lofter, because a 2" tube would need a lot of wadding. I cut three 2" plywoods disks and drilled a 1/8" hole in the center of each, plus 4 3/8" holes in each. I'm now gluing them onto a 2" lenght of 1/8" dowel with the 3/8" holes staggered. That way, ejection gas can still flow through, but its speed is restricted by the staggered holes and disks, and it'll cool down and not fry the chute. Pictures eventually.

NARCON 2010

Linky link

It's March 13-14, 2010, in Worchester MA at Clark University, just an hour from where I live! The National Sport Launch (NSL) and NARAM (NAR Annual Meet) are never near me, so I guess having NARCON nearby two years in a row makes up for that.

I had an awesome time at NARCON 2009, so I'm definitely going to make it up there again. I have SATs on Saturday morning (the 13th), but I'll be able to drive up in the afternoon, and maybe even stay till Sunday.

Tuesday, November 3, 2009

Yet another motor order!

I've ordered a bunch of stuff from Hobbylinc, because their prices are cheap than anywhere else, and they don't charge extra for HAZMAT. For 82 bucks, including shipping, I got:

Practical stuff:
48" red and orange streamers. Good for rocket up to 3 ounces, like Machbusters. And they were 69¢ apiece.
Aerotech Interlock igniter clip, for dealign with those bloody Copperheads
1 bag of recovery wadding

Motors:
1/2A3-4T (4)
A10-3T (4)
B6-2 (3)
B6-4 (3)
B6-6 (3)
E23-8T: for my 29/40-120 case. Not a load I would normally choose since it's a Blue Thunder and 29mm E loads are usually expensive, but it was on sale for a price comparible to 24mm E loads.
G53-5FJ: for the same case. The exact load I wanted, and it was on sale. Perfect for the Nike-Apache sometime.

Goonies!
3 Baby Bertha kits. One will become the Nike Goon, another the Mach Goon, and another to be determined. Possibly a Saturn V goon?
48" of 38mm tubing. For the motor mount of the Mach goon, and then I'll have 43" left over for whatever.

There was still more stuff I was tempted to get. Their 24mm reloads are dirt cheap, as are 24/60 cases. As soon as Aerotech brings out more 24/60 loads, I'll snatch one up.

Blogging will be light for a few days, likely, as I'll be staying for a few days at a friend's house where getting the internet requires finding an unsecured wireless network, or treking back here after school.

Monday, November 2, 2009

More information on AT 24mm Gs

On this thread on TRF, Gary Rosenfield has released some more information about the possibility of 24mm Gs.

He confirms they'd be for 24/120 hardware, which would presumably be a 2-grain configuration. According to the 24/60 assembly drawing helpfully located in the 'resources' section on the Aerotech website, the fuel grains in the 24/60 case are 2.85" long, hence the 24/120 case would be 7.2 (=2.85+4.35) inches long, including the forward closure but not the aft closure.

He also confirms that they're working on other loads for the 24/60, including Redlines. This makes the EGE very very happy. The fact that he says loads, plural, prolly indicates a Black Jack and/or Blue Thunder load in the works.

He says that the single G load currently in the works will be a core-burner, because a C-slot grain would require either a thicker paper liner or phenolic liner, which would be more expensive. Also, for multi-grain motors, aligning the slots requires taping the grain together - an extra step that if forgotten would likely prevent proper ignition of the motor, certainly result in a strange thrust pattern with a much higher initial spike, and possibly cause a CATO.

He also mentions that because it would be a core burner, it would prolly be over 80N average thrust, making it a High Power motor instead of a Model Rocket motor, which may or may not be allowed at the Salem field I usually launch at.

Sunday, November 1, 2009

Randomness

Finally finished my outline for my thesis paper. 4 pages in size 11 font, 1887 words, and that's just the outline. The finished thesis paper will likely end up near 10 pages and 2500 words, bigger even than last year's thesis paper for English.

I didn't get a heck of a lot else done today due to the paper. I've got the SR-71 almost complete - I glued the aft section on, and that's currently drying. All that's left is the landing gear bay doors, and of course gluing the complete side pods to the main body.

I drilled the launch rod hole in the pyramid with a 3/8" spade bit. It still needs a few fillets and possibly painting for aesthetics, but structurally it's 100% ready to fly!

24mm Aerotech G Possible

According to this thread on TRF, Aerotech may eventually bring out 24mm RMS G motors.

One poster speculated that one, probably the first, might be simply two F35W grains together, which would make roughly a G70W with about 110Ns total impulse and 1.4s burn time. That would work well with delays on perhaps 5,8, and 11 seconds.

If they really do, it'd be interesting to see what the hardware looks like. 120Ns hardware would be about 6 to 7 inches long - too long for 24mm mounts with an engine block, but just fine for something like the Mozzie or 24mm saucer. I'm hoping the hardware would at least be compatible with one of the two current 24mm RMS sets, likely the 24/60 which has thicker walls designed for higher pressure, and is designed more like HPR hardware than the 24/40 set.

If they really do come out, then they'd prolly come out several loads as well with more loads for the 24/60 case, which I'm really hoping will eventually include Black Jack, White Lightning (F35W), Blue Thunder, and maybe even Redlines.

All is still speculation based on 9 words from Gary Rosenfield, but fun speculation indeed!