Tag Archives: para

Tohickon Scouts Spring Camporee

Posted on by tjkopena

This weekend the Boy Scouts’ Tohickon District  held their Spring Camporee. One of the activities was earning a “Space Exploration” merit badge and the leaders had asked PARA if we’d do some demos and help out. It was held at Tinicum County Park, about an hour north of Philadelphia, which none of us were familiar with but turned out to be very close to the farm at which we usually launch. We didn’t quite know what to expect of the event or venue going in, but it was a great day all around. Weather-wise we got bluebird skies, no wind in the morning, and just enough shade and breeze later to not be insufferably hot. Tinicum Park turned out to be a very nice launch field for small to medium rockets. PARA also had good turnout, with 8 people there to help and hang out.

The photos here are a sampling of Ken’s.

Very serious launch site!

Display tables.

Checking out Jim’s big rockets.

Ken got the scouts to change the launch site on the field to a much better one, as well as to revise their schedule quite a bit, and really enabled a much smoother, better paced day. The scout leaders were happy to use our launch racks to further streamline, and Jim kept them all flying expeditiously with waves of twelve at a time. With the racks and the safety flags and some banners and everything, the scouts clearly all thought this was a big-time serious launch. Between all of us we setup four display tables overflowing with rockets, everything from Jim’s ~14ft 40+lb L3 certification rocket, to a whole pile of micro-rockets. Walt had made some posters about different motors and other rocketry aspects, and Steve’s Saturn V was a much appreciated prop for the scouts’ lectures. The two of them had steady business all day talking about the rockets on display. Fortunately, despite some high spirits and exuberance, our collection suffered only two casualties, micro-rockets that blew off the tables and got stepped on. Chris and Bill helped with setup/teardown and pre-flight checks of all the scouts’ rockets. Alice and I worked with some scouts not enrolled in their program to launch a few of our rockets, and conducted extensive comparative testing of the several types of cookies Walt had baked.

Putting in motors.

Learning how to connect launch control.

Ready for the first wave!

Blast off!

My count was 58 launches:

  • 46x scout launches
  • 4x Steve demo launches on As and Bs
  • 7x Joe & Alice demo/spectator launches (Doorknob E20-4 x2, Sputnik A10-PT x2, Spirit C6-5, Vortico A8-3, R6 Alice’s Star Rocket Micromaxx)
  • 1x Jim spool launch, I think on an F67, which absolutely 100%, totally ensured representatives from the polo match going on in the other section of the park would come right on over and politely but firmly ask us to stop scaring the horses

Helping some other scouts that came by prep a couple of our rockets to launch.

Talking about rocket gliders.

The recovery team heading out with the lineman’s pole in search of treebound rockets.

In all those launches only two rockets got hung-up in trees. Of course they were mine and Alice’s. Her Spirit drifted too far on quickly growing winds in the late morning, and my Doorknob drifted in a totally unexpected direction and just barely snagged the tip of a tree. This cast a bit of a pallor over lunchtime as its kit, electronics, and other accessories added up to about ~$250 just swaying in the breeze. Fortunately the wind continued to pick up as the afternoon went on, meaning we didn’t launch any other big rockets, but it knocked down the Doorknob! When I checked on the rocket mid-afternoon it had fallen another 20ft or so through the trees and we were able to snag it with the club’s 40ft pole. Two fins shattered in the process of pulling it free but are repairable, and the important thing was getting back the electronics. After that success the recovery team got motivated and successfully retrieved Alice’s Spirit, continuing that rocket’s exciting life—it was built by Alice at a club launch after Mike & Andrea gifted it to her and was immediately lost amid the summer corn, but found randomly at the next month’s launch by somebody looking for a different rocket entirely.

Having both rockets back in hand ensured an upbeat ending to a good day, and at Alice’s request we wrapped it up by heading off to her favorite post-launch pizza stop.

Success! Sort of!

 

Odd’l Sputnik

Posted on by tjkopena

Odd’l Rockets makes a cute little kit called Sputnik that’s real fast to build, flies well & easy, and is just a lot of fun. It’s a classic design of four dowels or bamboo skewers glued into a styrofoam ball with an insulating tube into which the motor is shoved.

Kit face card.

Typically these rockets are flown with no or minimal finishing. Most spray paints dissolve this kind of foam, so it takes some extra effort to paint, and flying au naturale keeps the weight very minimal. Building one recently though, I really wanted an actual Sputnik-lookalike smooth, shiny, metallic finish. Here’s what I wound up with:

Ta-da!

Not completely perfect, but I ran out of time, and it was getting heavy anyway. The deal here is that the ball is low density styrofoam that’s not smooth, at all.

(manufacturer photo)

Getting the look I wanted took a little finishing work:

  1. Coat of Modg-Podg and sand
  2. Coat of carpenter’s wood filler and sand
  3. Coat of carpenter’s wood filler and sand
  4. Filler primer spray and sand
  5. Filler primer spray and sand
  6. Black primer spray
  7. Black primer spray
  8. Metallic chrome spray
  9. Metallic chrome spray

That came out well, but the tradeoff is that the model’s a good bit heavier. It flies up well but doesn’t go as high and lands harder. In its usual unfinished state the design’s featherlight and simply falls down body-first (protecting the legs) and bounces. It might even still be going upward when the ejection charge goes off, giving the rocket an extra boost. The weight of my build means it’s decidedly arced over, coming down comparatively fast, and near the ground already when the ejection charge goes off, hurling it downward even harder. After two flights a notable crack formed in the shell. Still flyable, easily fixable with white glue, and not surprising, but definitely a price paid for aesthetics! In the future I’ll think ahead and order some plugged motors without ejection charges, eliminating that additional impact push.

In any event, despite not being as robust as I might hope, I really like the look of the rocket, it flies well, and was a crowd pleaser at this weekend’s club launch.

 

Rainbow Bobby

Posted on by tjkopena

Alice’s Rainbow Bobby, a very alternative take on Launch Lab Rocketry’s Bullet Bobby:

Rainbow Bobby is just suuuper super super excited to fly! Yeah yeah yeah!

PARA’s Jim H gave Alice this kit at January’s launch. It’s labeled as a Level 2 build but I think it’s a good kit for beginners. There’s almost no knife work (the fins come completely cut out) and you can produce a good result without sanding, sealing, or papering. Alice built the whole thing herself with minimal guidance.

Carefully measuring & marking where the fins will attach.

Assembling the motor mount.

One last check right before bedtime that the fins are still drying in place.

Gluing in the motor mount.

I did wind up doing most of the spray painting as the cans are too big for Alice’s hands to make the rainbow she wanted in such a small length. Even I had to talk her into dropping a couple colors. But I did follow strict specifications and supervision to achieve her intensely deliberated paint scheme. There was even a household vote on candidate designs. I admit I was skeptical at first of the stickers layout she came up with, but the rocket turned out very characterful and wonderful.

Very serious studies went into the paint scheme, including a household vote on a slate of sketches as well as computer aided visualization, all to wind up with… a rainbow! Surprise! I WOULD HAVE NEVER GUESSED.

Alice evaluating whether she wants to simplify the paint scheme to make it more feasible for her to paint, or take a gamble on trusting dad to execute her vision… Decisions, decisions…

Checking her notes before the all-important stickering phase.

The debut launch was… dramatic. The launch lug somehow bound on the rod and took it for a ride as the rocket looped hard into the ground right in front of us. After some field repairs to re-attach fins, launch lug, new parachute, etc., the second flight went up well but again lost a fin on landing, ending flights for the day. At this point Rainbow Bobby’s had fins ripped off on 3 out of 4 flights. Part of it is that the official motor recommendations are a bit underpowered and the delay too long for how much nose ballast is mandated by the instructions—it comes down hard. Compounding that, many launches this year have featured rock hard frozen ground, wrecking numerous rockets on landings that might be fine in summer.

To some extent I think the kit should have been designed with through-the-wall fins given how little attachment they have to the body and how far below it they hang. One tweak to the kit as-is that I’ve applied in our repairs is to drill holes in the body tube where the fins attach, to allow glue plugs to form inside. However, it’s a tradeoff; reinforcing inside the tube makes it harder to replace fins if/when they break rather than tear off. Another thought is that the ballast might be too much. It makes sense, but intuitively seems like a lot when you actually hold the rocket. Perhaps the design doesn’t account for the effect of base drag from the low fineness ratio (its stubbyness)?

Waiting for Bobby’s first flight!

Recovering our OTHER rainbow rocket, a stand-in for the less successful Bobby recoveries.

Sleeping off a big day and a couple disappointments on the way home (we also lost our Tall One super-roc to a tree).

But, this past weekend the ground was soft and it just happened that both of the cars next to us had their own Bullet Bobbies! So of course we had a Bullet Bobby Blast-Off, from which all rockets were recovered undamaged.

The lineup for the Bullet Bobby Blast-Off.