Rocketober 10

All this month I'm posting photos on Twitter for #Rocketober. They'll appear here with slightly expanded text.

Still under the weather, I've only taken a few more steps on construction of Sky Wolf.

The rocket comes with two inch-long launch lugs for a 1/4 inch launch rail. Simply gluing on the lugs would be the simplest option, but I also consider using launch rail buttons.

Why? Well, a couple of reasons. The first is that a launch rail is a nice and sturdy launch platform. Last fall, I had some trouble with a few heavier rockets which was partly due to some wobbly launch rods. That probably wouldn't be an issue for this rocket, as those were clusters. But the rod-based launch pads my club uses can be a little tricky sometimes. The bases of them are metal fence posts hammered into the ground, and the heads are on a swivel. Sometimes I have trouble getting the launch rod to point where I want it to. Either I can't make it cooperate and angle it into or away from the wind direction as I'd like, or I try to get the rod perfectly vertical and I can't do that.

The NAR recently recommended angling all launch rods and rails away from spectators rather than launching vertically. However, this is a guideline, rather than a rule. Sometimes, depending on the direction of the wind or the proximity of the spectators, launching vertically may be preferable. You have to use good judgment for safety - as well as to minimize risk of losing the rocket (so long as you observe safety first). I have had a few rockets go nearly horizontal because they weren't launched vertically (mostly two-stagers) and leave the field. So I want the option.

Our rail pads are easier to control.

Most high power rockets use the 1010 rail button for a 1-inch wide launch rail. While people do put 1010 buttons on smaller-diameter rockets such as this one, they're a bit big for my liking on a rocket this size.

Another option is the "mini button" from rail-buttons.com. This is a launch button for the smaller metric rail, sometimes called a 2020 rail. Still very sturdy, but with a much smaller button. My Ventris uses these buttons.

On a rocket the size of Sky Wolf, the mini button is less obtrusive. It doesn't even stick out as far as the launch lugs supplied with the kit.

A third button option is the "micro button," also from rail-buttons.com. It's for use with a MakerBeam launch rail, and is really small.

Micro buttons do stick out further than they need to for the MakerBeam rail, but can be trimmed with a hobby knife.

Sky Wolf is pretty small, and not very heavy, so the micro button might work just fine. But if I fly the rocket with an H motor, I'm just not sure. So I decide this time to go with the mini button.

I drill two pilot holes into the airframe, directly into the forward and aft centering rings, offering more support for the rail button screw. A drop of thin CA - cyanoacrylate (superglue) - into the holes will stiffen the paper fibers.

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Rocketober 3, 2016

All this month I'm posting photos on Twitter for #Rocketober. They'll appear here with slightly expanded text.

I recorded a new episode of The Rocketry Show podcast last night, so this post is on yesterday's tweets.

"Day 2: Rocket t-shirt"

 I don't have any rocketry t-shirts (though I should), but for yesterday's theme, I posted this. I bought this NASA shirt to wear while teaching Rocket Camp, and wore it to my first club launch. That's me with Trident, a scratch build of mine before its last flight.

All fin slots have been cut, and here is Sky Wolf dry fitted together. Note that nothing is glued in place yet (except for the aft centering ring, which I did on Day 1).

Sky Wolf is small, but powerful. Only about BT-60-sized, it has a thicker airframe, and can hold 29mm motors. It can fly fast and high on composites, and can take anything from D to H impulse!

A notch cut out of the forward centering ring. The Kevlar shock chord will pass through this and be anchored to the motor tube.

A knot tied in the shock chord 3 inches from the end.

The knot serves to help anchor the shock chord, acting as a stop to prevent it from slipping through the notch in the centering ring.

The spiral grooves in the body tube were shallow but wide. They filled easily with my minimal-sanding method.

The stressful moment of getting the forward centering ring glued exactly in the right spot - not stuck too far forward or aft - is done.

Finally, the end of the shock chord gets dipped in epoxy, laid onto the motor tube, and wrapped in black electrical tape to cure. Once the epoxy is cured, the tape will come off.

There was too much chance for a mess at this point, so I didn't photograph the epoxy process. I needed to get it on there and wrapped up before it ran anywhere. You'll see it when I take the tape off.

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Sky Wolf Sim

I've created a simulation of the Sky Wolf in OpenRocket, and it looks pretty close.

I'll need to print out fin templates and compare them to the real thing to be sure, but after tinkering with it for a few hours, I think I have a close enough sim.

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#Rocketober Tweets for Today

Time to pick a build for #Rocketober. I have so many Estes rockets
I'm going with something else. Here's my non-Estes build pile.

I've been posting a ton of photos to Twitter for #Rocketober. Here's what I've done so far today.

From the selection pile - the Apogee Components Avion.
I've built 4 of these and have one to paint, so I'll save this one.

Quest Astra, a leftover kit from rocket camp. Will build another time.

The Quest Magnum Sport Loader. I bought after my 1st had some minor flight damage.

Definitely out of production - the Red River Rocketry Blue Shift!
I think I got the last one in the world a couple years ago.

A limited edition, designed by Crazy Jim of SkyPyrates - the Sky Wolf. This is a National Sport Launch 2015 commemorative rocket. Small but powerful with a 29mm motor mount, it can fly on anything from D to H motors.

The FlisKits Tres - a three-motor cluster rocket. I bought this from Jim Flis at
a launch after chatting with him about airbrushes.

The Quest SuperBird - a low and slow rocket. I think this one is out of production as well.

This is a big one - the Mad Cow Rocketry Aerobee 150A. It's a scale model of a sounding rocket, and has a 38mm mount.

I'll also soon finish a scratch-built copy of the Estes Hi Flier XL with a payload section.
I'm building the original Estes kit at the same time.

Decided on the Sky Wolf

Checking the parts. That's a 12-foot Kevlar shock chord.

The Sky Wolf comes with some nice vinyl decals.

I'll measure and weigh all the parts to build a simulation in OpenRocket. Here, I'm measuring the nose cone.

It's an 8-inch long (spherically-blunted) tangent ogive.

The nose cone is hefty, and has some nose weight added to the tip. I had to find the real CG for the simulation.

The NC alone weighs 91.4 grams.

Careful notes on the sizes, masses and placement of all the parts will help me make an accurate sim.

The aft centering ring is glued on. The instructions say to use epoxy, but wood glue will work fine for
this rocket. It's also less messy and lighter in weight than epoxy, so I don't have to mix anything.

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#Rocketober Photo Blitz

Apogee Components sent out this tweet today:

For the month of October, Apogee is holding a model rocketry photo blitz challenge on Twitter and other social media platforms.

I think this is a great idea! I'm convinced that model and high power rocketry are not only alive and well, but growing. Still, it does seem to be a somewhat underground (ironically) pursuit. Model rocketry doesn't seem to have the public profile it had in the 1960s-80s. Just three years ago, when I saw a model rocket kit at Target, I was surprised that "people still do that." Whenever I tell a new person that this is my hobby, they are always surprised. Most of them have never heard of it. A small few suddenly remember doing it as kids.

But rocketry is a hobby that I think a lot more people would enjoy if they knew about it and tried it out. A social media campaign might be a cool way of spreading awareness of rocketry.

My Twitter account is devoted solely to rocketry in general, and this blog in particular. But a lot of people have personal or professional Twitter accounts. One person I've started following recently is Sharon Robinson, who is not only the acting Joint Head of Conservation and Collection Care at the Museum of London, but also a passionate rocketeer and prolific builder. It's great to see someone sharing her love of rocketry alongside her other personal and professional activities.

The idea of the photo blitz is to tweet a rocketry photo every day in October, and tag the photo with the hashtag #Rocketober. Not a bad idea to add #ModelRocketry or #HPR to increase the engagement of the tweet (the likelihood it will be seen and shared). Apogee will re-post their favorite photos each day. And they've come up with a theme, which you can read about here.

Of course, you don't have to follow the theme, and you can post more than one photo a day. I plan on posting one Apogee theme-based photo each day, and a ton of others as well. And while I'm at it, I'll probably post them here as microposts, without much explanation.

For every photo I post on this blog, I take probably 50-100. Some are meant for later posts, some are duplicates to make sure I get the shot. And some are great, but I never find a use for them here.

Assembly line build

And there's no reason not to post #Rocketober photos on Facebook or Instagram as well, if you are on those social media platforms. Both of those support hashtags, which can be a good way for people to find things that interest them.

I hope you join me (and Apogee) in tweeting tons of rocket pics. It'll be great to see them, and re-tweet or share them. Let's see if we can get rocketry to trend!

Note: A search of the term #Rocketober brings up a few rocket-related posts from previous years, including one photo I found of a Saturn IB, as well as a couple having something to do with yoga. Who knew?

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Micropost: PSII Ready To Go

Due to drought, the fire marshal in Amesbury has said we cannot launch there. Too much dry grass.

Good news is, the FlisKits Anniversary launch has been moved up to Berwick, Maine, thanks to the Maine Missile Math and Science Club. They have a much larger field, much larger recovery area, and a 10,000 foot ceiling for HPR. That's twice as high as our permitted flight ceiling. They also launch on motors up to M impulse, which means I may see some mind-blowing stuff this weekend. I've wanted to get up there for a year now.

I finally finished Ventris.

This rocket is tall and beautiful, and I can't stop staring at it.

All three of the Estes Pro Series II rockets I wanted to finish are done. I'll be doing a level 1 HPR certification attempt with the Leviathan.

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Micropost: A Surprise from Dog House Rocketry

I got a nice surprise in the mail this week from Bill at Dog House Rocketry, LLC.

Now, some of you more advanced rocketeers might already know what these are for. But, for everybody else, I'll elaborate after this weekend's big launch.

Let's just say, I'm really excited about these. Thanks, Bill!

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Micropost: Chute or Streamer - Decisions

Sometimes it's hard to decide whether to use a parachute or a streamer for recovery. A chute will bring the rocket down nice and softly, but more slowly. In that time, the wind may cause the rocket to drift, increasing the likelihood of losing the rocket in a tree or over the hills and far away.

A streamer brings the rocket down more quickly, so there's less drift. But a harder landing may cause more damage to the rocket.

Above is my sim of the Estes Goblin, a rocket I've built but never flown. The kit came with two streamers. But I built the rocket a little on the heavy side (so it may fall more quickly than Estes had planned when designing the kit), and it came out quite beautiful.

On the one hand, I don't want to lose it. On the other, I don't want to damage the lovely paint. And since the rocket may top 1200 feet, I have some thinking to do here.

I may compromise and go with a tiny six-inch Mylar chute, which should split the difference in descent times. It will also sparkle in the sun, which may help me spot the rocket in the sky as it descends.

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