Pre-Flight Data Capture Form

I brought the booster section and AV-Bay up to bong this weekend to show my latest progress, and one of my TAP sponsors asked to see my pre-data capture form. Of course, I didn’t have it, so I’m posting it here to make it easily accessible the next time he asks

 

 

Sand, Prime, Repeat

     The good news is the new pads for my sander came in (picture on left). The bad news is that means I have a LOT of sanding to do. I took advantage of the weather last week to start the lengthy process of sanding, filling, priming, and sanding again to get a nice smooth finish on the rocket. The glassing of the wings turned out a bit messy because of the limited space (about 1.5”) between the trailing edge of the wings, and the leading edge of the fins. I couldn’t find a way to properly keep enough weight on the curing fiberglass to provide the same clean surface I ended up with on the wing tops and fin can. Worse, I can’t really fit an electrical sander in that area, so I’ve had to create all sorts of sanding devices to get into that area. You can see what looks like multiple colors on the wings and fins in the picture on the left. This is indicates in some areas I have sanded through the top layer of fiberglass into the Kevlar. That’s not necessarily a good thing,

so I’m now using a different technique to smooth out rough areas, and even out all of the surfaces. I cleaned the surfaces, and sprayed a first coat of primer. The primer will even out many of the smaller pinholes and rough areas, but more importantly, it will allow me to see very quickly when I’ve sanded through into the fiberglass with the big difference in color. My first pass turned out smoother than I had anticipated, but up close, it still looks like Mickey Rourke’s face – that’s not a good thing. I have three major areas left on the rocket:
1) electrical
  I still need to install the switches, terminal blocks altimeters, GPS devices, and RF trackers  into the rocket and AV-BAY.

2) Nosecone
     The Nosecone shoulder still doesn’t fit  into the upper sustainer. That means more sanding, or, worst case, cutting the shoulder, and replacing it with a new home-made shoulder from a coupler. I also may need to add weight to the nosecone, and probably foam it. I’ll also need to make bay’s for tracking equipment, install all-thread, a bulkhead, and weight bearing anchor.
3) Sanding & Painting
     My plan is to put a really nice airbrushed paintjob on the rocket. Black base with winding flames is my current plan.  This will require a very smooth surface, which means lots of priming and sanding. I’m going to wait until the weather turns a little nicer so I can do this outside, and avoid ruining all of the surfaces and cars in nice garage. My wife hasn’t said anything yet about all of the dust, and I don’t want to push my luck.
    II will probably be taking a break for a bit on the construction side. Work travel is picking up a lot, three of my four daughters need pinewood derby cars made by mid march, and I still haven’t finished those crayon rockets I gave my kids for Christmas. With that said, I’ do plan to finish #1, #2 by next month so I can get a ‘practice’ launch in before the big event in April. Hopefully my leg will have recovered enough for some rocket hunting

It’s alive!

     The weather was beautiful yesterday in the Chicago area – a Balmy 52 degrees! I moved the rocket to the garage, but couldn’t resist putting it together for the first time. I still have a fit problem between the nosecone and sustainer, but finally looks like a rocket. It’s supposed to be another nice day today, so I may try to get a few coats of primer on the booster section to see how much sanding and filling work I’ll really need to do – the fin and wing glassing came out much smoother than my usual work.

On a wing and a prayer

     Unfortunately, I tore my calf muscle about a week & a half ago skiing in Utah, which has really put a damper on rocket building and pretty much everything else. Worse, I have taken a lot of my OLD rockets out of storage  few weeks ago (a Brutus, Maximum Thrust Thunderbird, and a few other 15+ year old HPR rockets) to show my kids, and clean up for flying this weekend at Bong. Given how thick the snow is, I can’t imaging wading through it all in my leg cast trying to recover the rockets . I’ll still go up to see if either of my tap sponsors want to see my progress, but if I fly something, it will be small.
     I was able to get the wings on. First, I had to re-cut the wing slots. The lower portion was glassed over when I made the fin-can, and the whole slot itself wasn’t quite thick enough for the wings to fit through. I repeated the process on the other side, until I could dry fit both wings with a tight fit. One of the issues I will have with the wings is my limited ability to make interior fillets since both sides of the centering rings are already glued in place. First, I filled the interior of the wing’s nomex honeycomb with epoxy and put it into the slot. I let the epoxy ooze out of the honeycomb, then removed the fin. This gave me a line of epoxy on the motor tube where the wing made contact. I repeated that process a few times to build up the epoxy on the motor tube. I then  drilled a few half-holes in the wing-slots which allowed me insert a syringe into the body and add epoxy for a sloppy, but effective internal fillet on each side of the wing. Once it was dry, I was able to look through the upper center ring hole I made to pour foam to ensure a the wing was touching, and had a a fillet, and taped it up to cure. I repeated the same process on the other side until both wings were secure with internal fillets.
I used the same epoxy and process for the wings, that I used on the fins. Measure and mark the fins and sustainer, lay down tape across the markings, and fill in the middle with epoxy. The process was a little more tricky than the fins because the wing is more than twice the length. Worse, there was not enough clearance between the wing and the fin for me to use the same diameter washer I had used on the fins. Eventually, I settled on using my finger to spread, and create the fillet, dipping it in alcohol between pulls, exactly like using the washer. The result was significantly more messy, but just as effective in creating a very smooth fillet, with clean lines. This will reduce the amount of sanding I will have to do before glassing the fins.


  
      Once everything was dry,  I separated the booster from the upper sustainer which I was using as a lever to keep the lower sustainer in my rocket holder  to mount the sustainer upright. It’s foam time! Once again I calculated the empty volume on each wing side, mixed the proper amount (266 ML, half part A, half part B), made a quick funnel out of paper and poured in the foam. Within about 5 minutes, the foam had expanded, almost perfectly to the bottom of the pour hole. I love it when a plan actually works so well! I repeated the same process on the other side,  mixing exactly the same amount of foam, but when it was done expanding, I could barely see to top through the pour hole. Yikes! Luckily, my kids weren’t around to see the utter failure of math and science’s ability to predict an outcome. II now had no idea how much volume was left in the sustainer, so I had to do the one thing I hate to do…. guess. As you can imagine, I didn’t guess right, and you can see the results on the right – an oozing mess out of the top of the second pour hole. Luckily, this is not as bad as it looks, and I have a fair amount of experience digging foam out of tight spots thanks to a lot of lawn darts during my magnetic ejection trials. five minutes with my trusty foam extractor (a special grapefruit knife), and a little sanding, and it almost looks like I got it right the first time. I’m now going to move everything out of my office and into my garage in preparation for the massive amount of sanding I’m going to need to do. I would like to thank an anonymous reader for the tip on where to find sanding discs for my 3d sander. A kit of 100 can be had at a retailer named  Micro-Mark here. Of course, there are lots of other goodies to be found at Micro-Mark… My package arrived the other day filled with lots of tools I didn’t know I needed until I saw them in the catalog

Odds and ends and nosecones

   Spent much of the day cleaning up from the snowstorm. My four kids were school free yesterday, so I spent the day shoveling, and playing in the snow with them. I did find a little time for the rocket. The picture on the left is the original plastic nosecone. The one on the right is it’s Scotglas fiberglass replacement. Scott Broderick, a WOOSH member happened to have an “extra’ 7.5” nosecone he was willing to sell.  I was in the right place, at the right time, as this is a custom nosecone, and they can take forever if you order them. I was thinking about building my own, but a certification rocket didn’t seem like the right vehicle to be learning something so critical. The bad news is because this is a custom nosecone, it didn’t fit my upper airframe at all – the shoulder’s outer diameter is too large for the magnaframe. I was able to sneak away and do a LOT of sanding. No way I was going to do this in my office. You would be surprised at the amount of fiberglass dust even a small sanding can create. For sanding curved surfaces, I use a Crasftman 3D sander. The sander has three floating heads each with their own circular sanding pad. This lets the sander conform to most curved surfaces, reducing the possibility of creating a slat spot using a traditional sander. Unfortunately, they don’t seem to make these anymore, so the pads are becoming a little hard to find. This is an indispensable tool for me, so if someone knows of a reasonable alternative, let me know!