Monday, October 12, 2015

The start of the Fett Boy

Here's the upper part of a rocket inspired by the famous Estes Fat Boy. I found a tube that will fit in the bottom and will telescope over 3" tube, forming a reverse shoulder. It will get a 29mm mount. Just about all I need is fin material. Will only fly at MDRA.

Saturday, October 10, 2015

Launch Report 2015-10 (MDRA ESL-208)

Location: Central Sod Farm, MDRA
Weather: sunny, mid 60's, wind started at 15+ but started calming after 1PM
Total flights: Today - 5; YTD - 70
Total motors: Today - 9; YTD - 85
Motors by class YTD: MMX-2; A-7; B-4; C-24; D-6; E-11; F-20; G-8; H-3

Water rocket flights (not included in the totals above): 6


It was very windy when I got to the field and I was a bit bummed. After spending an hour and a half trying, unsuccessfully, to recover Bat-mite's rocket from  the trees, the wind started to calm. It was in a favorable direction so I had a couple of long walks. I had less little shooting an arrow over his rocket. It was higher and deeper in the tree than my prior success. On the final shot, I think I might have had it. Unfortunately, I ran out of fishing line. Rats! I hadn't considered that possibility. I'll have to figure out how to get some more onto the reel.

My Flights:
  1. Not-a-MIRV on three C11-3s - The flight was a bit low for three C11s but it was nice anyway. The induction tubes were a bit sooty but weren't damaged.
  2. DG&A Lazarus on an H550-10 - Very fast and high. And a long walk. But no trees were involved.
  3. Public Enemy Ultra Fatboy on a G185-6 - Another fast flight. It ejected very late and the 'chute tangled. The nose stuck deep into the moist sod and one fin was buried. No damage.
  4. Estes MIRV sustainers on three A10-3s - Since I lost the booster to the beans, I decided to fly the three sustainers off a single standard LPR rod. The top two flew off nicely but the first CATOed, probably due to an off-label ignition method.
  5. Estes Cluster Bomb on an F44-8 - I built this to fly on E and F motors but, for over ten years, it had only flown on C's and D's. Well, it flew great on an F44!

Tuesday, October 06, 2015

Well, it may not be a MIRV, but it WILL be HEADS UP

I got tired of worrying about fins on the Not-a-MIRV so I just grabbed some out of the scrap box. I'll award extra Brownie Points if you can guess what rocket they came from. I cleaned up the roots just a bit, scraped paint so they might stick, and touched up the flaws with Sharpies. Hey, they will probably burn off anyway. They are bigger than I had anticipated and probably not big enough to make the coast-stage stable. Hopefully, GDS does it's stuff during boost. Saturday is looking wet but Sunday looks promising.


Monday, October 05, 2015

It's still Not-a-MIRV

Here's the progress on this simple build. I have to touch paint the lug. I had hoped that a 1/4" rod would fit down the middle between the tubes but found it was a tad tight. So, I added a lug after it was painted.

I also have to decide on fins (or the lack thereof).  I didn't expect the Rocksim model to be usable and it clearly isn't. It goes from completely unstable with no fins (as expected) to amazingly stable on the tiny fins shown in my previous post.  The altitude part of the sim also went crazy. It was showing a bit over 1000' on three Cs. Then I tweaked the length of the nose cone and it is showing over 4000'. I only offer this to show that you can design things in Rocksim which won't work in the real world. Surprised, eh?


Sunday, October 04, 2015


I'll preface this post by noting that the Coleoptere/Stovepipe/Coccinellida build has officially stalled. It will be on the back burner until I run across another ring tail option.

My latest project was inspired by the Estes MIRV.  After the third sustainer from my Estes MIRV was recovered from the soy beans, I set a plan to launch the sustainers off a standard rod. Then this popped into  my head: If a finless, induction stabilized rocket is fun, maybe a cluster would be even more fun. I don't know why I am so obsessed with a class of rockets that run such a high risk of being single use. Maybe the same reason I used to like 29mm 'Machbuster' style rockets, which were usually single use but for another reason.

The build is underway and, for lack of photos, I offer a 3D rendering from a 'what-if' Rocksim model.


As mentioned, this is induction stabilized but I didn't bother segmenting the body tube so I could make an intermediate section transparent.  The body tubes are 18" BT-60s. there will be an air gap (not finalized) and a set of 3.5" induction tubes, The nose cones are plastic Easter Eggs that happen to fit the BT60 perfectly. These were hot-glued onto a coupler. I just couldn't justify wasting nice balsa cones on the rocket. Plus the Easter Egg cones are nice and light.

I was kicking around 18mm vs 24mm mounts for C6s or C11's, respectively. It turns out the 18mm CRs were backordered and I have C11's, so I went that way.

I am also finalizing the interconnection between the main body and induction tubes. I have given up of making the induction section easily replaceable. Just too much work for such a build. Instead, I will merely try to ease the pain of the inevitable repairs.

Then there are those fins. I am trying to decide whether I should go totally finless or go with some tiny ones. Since I have one totally finless rocket, I don't feel the need to be a purist. Also, my experience with the Saturns is that, if there is a small amount of natural stability, you get some flight during the coast phase (vs. a wild tumble).

The name was chosen to let everyone know that, unlike the MIRV launch, there will only be one piece to avoid. (The name tagged onto this photo is an older placeholder and I can't easily get rid of it).

Sunday, September 27, 2015

NARHAMS Night Launch photos

A fellow NARHAMSter also took some photos from yesterday's launch AND he stayed for the night launch. Here is one sample. If you like it you should click through and look through David's entire album!


First impressions are often WRONG

After I recovered my Saturn V SA-666 from its month-long vacation in the trees, I gave it a quick once over. It was faded, a few wraps were warped, the ejection tube and nose section's shoulder were slightly warped and the nozzles were all floppy (except for the one that broke off). It looked totally fixable. The warped tubes seemed to be adjustable and I though a few new paper wraps and a coat of paint and I could fly it again. Well, that wasn't going to happen. The worst part was the paper motor tube was in terrible shape and the 24mm-29mm phenolic motor adapter refused to come out. One good whack with a pipe from the top and the adapter broke. Right now, the Estes retainer and the plastic 'chute is all that I'm salvaging. (sound of taps playing)


Saturday, September 26, 2015

Launch Report 2015-9 (NARHAMS)

Location: NARHAMS, Mt. Airy
Weather: 70's, 10+/- mph, cloudy
Total flights: Today - 7; YTD - 65
Total motors: Today - 7; YTD - 76
Motors by class YTD: MMX-2; A-4; B-4; C-21; D-6; E-11; F-19; G-7; H-2

Water rocket flights (not included in the totals above): 6

It was quite windy but the direction was fairly favorable. That is, rockets would stay away from the evil trees but the vector was towards the ball field/pavilions/parking. I ended up scrubbing several flights.

My main goal for this launch was to try out my Tree Rescue System. The target in this case was the Saturn V, SA-666, which was lost in August. I'm happy to say I was successful thanks to my wife and one Mike Kelly. My wife lent much needed hands and Mike suggested pulling in a direction that broke the snagged branch. He also did the pulling but I think the key was the direction. It only three shots to snag the proper branch and the process was successful. Based on what in theory is 100' of paracord, I estimate the rocket was 43' up. I'll put the details of the process all the way at the bottom of this post.

My Flights:
  1. Tiny Tim Smoke on a C11-3 - nice flight
  2. Alaska Paper Model Works Paper HoJo on an C11-3 - Due to the wind, is was suggested that I use a smaller motor. So, I ditched the planned E12 in favor of a C11-3. It had flown on an E12 and D12 and I was a little nervous about the C11. It was a low flight and ejection was late but the 'chute did open in time. I was adjacent to the LCO table and actually caught the rocket!
  3. First Flight Semi Sonic on an A8-3 - nice enough
  4. Estes GBU-24 Paveway III on a B6-4 - nice
  5. Half Spool Jack-o-Lantern on a C6-0 - cool
  6. First Flight Corn Roc on a C6-3 - Well, this is my theory: One lug broke off and the 2nd one bound on the rod until it broke off.  The it nose-dived and flopped around. I need to replace the lugs (will try epoxy and will poke small holes in the non-porous surface). I also need to work on the tip of the nose cone section.
  7. Half ASS-tron SuperRoc on a C6-3 - nice with a longish walk
As usual, there are photos.


This is how the recovery device works:
  1. Knot the fishing line and tape to an arrow.
  2. Insert the arrow. I really could use a string in the pouch to mate with the arrow nock.
  3. Aim, shoot, recover the arrow.
  4. If you shot over the proper branch disconnect the  line and reattach it to some kite cord. If not, disconnect the arrow, reel the line in and go back to step #1. I got it on the third shot.
  5. Here's where it helps to have more hands. Reel the fishing line and kite string in. One set of hand reels the fishing line in and one makes sure the string is reeled out. This could be done with one set of hands but it would be more tedious.
  6. Unhook the kite string and tie it to the paracord.
  7. Reel in the kite string, pulling the paracord over the branch. More hands were useful here too!
  8. Once you have both ends of the paracord, start shaking and yanking.
I thought the rocket was getting lower, but that didn't initially make sense since the branch was only lower when I was pulling. It turned out the elastic shock cord was rotten and as I shook the branch, the cord slowly stretched out until all the rubber was broken. As mentioned above, I was getting nowhere until Mike suggested pulling backwards against the direction of the branch. It snapped and I got the rocket back. It's in poor shape but I will rework it.