Der Red Mix - fins in place

Today I coaxed the final fin into place and it's curing now:

All that's left construction-wise is to JB Weld the motor retainers in place, drill the rail guide holes, load the nosecone tip up with 22 oz of lead shot and epoxy, and tether up the recovery system. Cool! Oh but then I need to fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand, fill, prime, sand!!! Dammit!

All work and no play makes Jack a dull boy...

Der Red Mix - fin reinforcement time lapse video

I sped this video up roughly 50x so as not to bore you. The fins turned out pretty well. They were initially fairly warped so I took them to work and placed them in an environmental chamber at 30C/80%RH to rehydrate the over-dried plywood. As I depleted one partial roll of 6 oz. carbon fiber fabric I decided to dip into my Kevlar/CF hybrid roll for the final 2 of 6 fin swatches. I should have used three Kevlar/CF swatches but this was a last thought for durability:

Oh and, once cured, the fins were surprisingly difficult to separate despite the use of vacuum film between each fin. The resin content is quite lean so the technique worked and I'll use it in the future.

Leaps and bounds

All of a sudden this thing's really coming together. I cut all the airframe holes tonight and everything's piecing together peachily:

Despite all my Illustrator pre-work and all the iteration I still managed to aim the camera basically down a fin. It's a 16:9 aspect ratio camera and it's focus is fixed below the fin but still. Duh. The final motor tube/e-bay assembly's curing now. Tomorrow night I'll reinforce the fins and epoxy the entire booster together when that's done. I really need to complete the construction soon because I want this to be super glossy when painted and I have all those awesome Sticker Shock decals to apply before LDRS...

Now featuring even MORE progress

Yesterday I added one wrap of 6 oz. fiberglass to Der Red Mix's main airframe using Dave Triano's technique. This is mainly for aesthetics and secondarily for durability. It's very difficult to apply excess resin to this much area so there are many gaps in the otherwise glossy finish. It's also tough to apply adequate hoop stress on the 14 mil Mylar™ film so that didn't help this surface defect either. It'll finish up nicely anyway so I'm still happy with the result:

Here also are some studio shots of progress on the electronics bay and I think they better convey the final layout. This whole assembly will be epoxied into the above airframe after I cut fin, e-bay door, and video camera slots into it:

Construction progress

I continue to make progress on Der Red Mix's electronics bay and motor tubes. Right now I only have e-bay pix, however, so here they are:

The Flip MinoHD camera fits nicely through the side and I have room for both Parrot 2 and Raven altimeters + 2 9V batteries on that removable G10 board. I'm also working on the hinged door for the front and a simple plywood cowling to reduce drag on the dangle-cam.

I also finished building my Madcow Squat for the drag race at LDRS 29. Now I just need to finish and paint that puppy and it's all set:

Der Red Mix tube session and test fit

Tonight I was inspired to drill the extra holes in all four centering rings, cut the motor tubes to length, and mark them precisely according to the plan a few entries below. Everything went together nicely but before I apply any epoxy I realize I need to finalize the electronics bay mounting board first.

You'll notice that I've elected to dual-attach the shock cord on the upper plate. I think this should reduce the tendency to zipper as the load will be divided in half. I'm quite sure the Gates Brothers used to employ that trick. Also that single aluminum tube bridges the electronics bay to the motor area and will facilitate e-match wire transport. Hopefully this week I'll get this whole assembly done and the rest of the build should prove fairly trivial. I think the first flight will probably be a central CTI 1596K500 Red Lightning motor on the ground then air-starting 2 x 408I345 White Thunders. Niiiice!

Viciously Mean Machine 0.75

I'm still working on the full 48" payload for the 100% Viciously Mean Machine but, in the mean time, I bought a Performance Rocketry aluminum-tipped, carbon fiber, conical nosecone and it just looks bad ass with the shorter payload. That booster will fit a CTI 6GXL casing so I hope to fly an L935 in there soon.

[I corrected the lens distortion present in the other version of the image.]

Hey, blog spammer shitheads!

I'm honored the Mandarin-fluent geniuses like [ElvisS_S blah blah blah] assume that enough people read not only my blog, but comments on individual entries, that it's worth spamming me. I will always immediately delete your drivel so find someone else to pester, shitheads!! Seek some less annoying way to earn a living.

Der Red Mix's precise design

Last night and this morning I worked up several templates based on my size/position guide (click image for larger version):

As this will be my most complicated scratch-built design ever I found it necessary to plan all the part positions precisely up front. I highly recommend either Illustrator or CAD for this purpose and I used the former in this exercise. I just need a few more parts and I can start cutting and adhering.

Repair day

After finishing my taxes today I decided to repair several ailing rockets despite needing to build/finish several others.

First off I fixed the 4" bullet after an early I366 Redline flight with yet another incredibly short delay. That was the last of the Redline motors I bought 'round about 2002 and, even storing the delays separately, these old motors accelerate the delay burn by roughly 6x. As such the ejection charge blows even before the motor has burned out (and yes I'm certain I assembled the motor correctly). This is the third old Redline that's behaved the same way so I sense a trend. The bullet suffered a zipper about 1.5" long right through the carbon fiber reinforcement so it was going damned fast at the time. Luckily I had enough room above the coupler that I could just slice the zipped section off and the nosecone still fits unmodified:

If this rocket suffers another event requiring repair I'm cutting my losses and tossing it!

Secondly I'm trying to correct a warp in my Viciously Mean Machine's 48" payload section. I'm quite certain this happened during carbon fiber reinforcement due to inadequate support while curing in the oven. Today I taped a 10lb. weight to the high point in the tube, suspended it in the curing oven on a contiguous 1" dowel, and post-cured for roughly 35 minutes. I'll check it in a bit but if that didn't work I might be scrapping a second payload section. Dammit:

Finally I had experienced a wall deformation in my 7.5" Nike Smoke on its last M1939 flight. I'm quite certain this was because I flew it single-deploy and, when the 16 foot Rocketman 'chute inflated from the payload section, the payload coupler came out an an angle and cracked/deformed the top of the tube. I mixed up a batch of West Systems epoxy, dropped in a liberal amount of Kevlar pulp and white pigment, and slathered that mess on the inside of the tube. I then used packing tape on the bottom of the tube to prevent leakage, topped it with a sheet of vacuum bag film, laid in a section of 7.5" tubing, and clamped the whole thing together. I think this will work pretty well after I grind off the excess epoxy:

I'm way behind in my blog posts so I'll list what I still owe here so I don't forget:

• March Plaster City launch report
• April Plaster City Launch report (featuring 9,140' I284 flight which I think is a record)
• Inexplicably wacky ARTS2 altimeter behavior
• Mad Cow Squat build (due before LDRS 29 in early June)
• 2000MPH President's Challenge build (Due before May Plaster City launch)
• Der Red Mix build (Due before LDRS)