Saturday, October 14, 2017

Those Crazy Rockets - They're Everywhere


Posted online by a DJ friend of mine from my radio days, a quirky, rocket-themed album cover of cheesy organ hits.

I'm pretty sure that's a Nike Ajax missile in the photo.

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Monday, October 9, 2017

Signal Alpha


Hello, again. It's your old pal, the Rocket N00b.

I haven't written in a while, I know. And, really, this post isn't exactly n00b stuff - it's pretty advanced model rocketry, in fact.

But tonight, I got an email from my friend, Joe Barnard.


More specifically, I got an email from Joe's company, Barnard Propulsion Systems.

I met Joe about a year and a half ago, while he was trying to build a model rocket which would not only stabilize itself through thrust vectoring - the kind of finless, active stabilization used by real space launch vehicles, where the rocket adjusts the direction its engines are pointing, to keep the rocket upright in flight, like balancing a broomstick on your fingertip - but also land under thrust, using a second hobby rocket motor. The idea was to create a working model rocket which flew and landed a bit like SpaceX's Falcon rockets.

Joe Barnard prepping an early version of Scout at the first launch I witnessed.


The landing legs

An early version of the gimballed motor mount with ascent and descent motors.

Other than that one obsessive project, he wasn't really into model rocketry.

But I got to tag along to a few test launches, some more successful than others.



Eventually, Joe came with me to a few NAR club launches, and to my surprise, decided to go for a Level 1 high power certification, which he successfully completed with his scratch built rocket, Thrusty McThrustface, on his first attempt.



We've been working on a story about Joe for some time on The Rocketry Show podcast. As he got better and better at thrust vectoring, he eventually decided to see if he couldn't make a commercial thrust vectoring kit available.

Well, guess what - he's done it.

Signal Avionics, his thrust vectoring system, is apparently ready for a limited, experimental release to the public. A small run of 30 units will soon be ready to ship! The system costs $299, and is only available in the United States for now. But this is some exciting stuff. To reserve a unit, click here and fill out the form.

(For the curious and the cautious out there, sometimes folks in online forums have suggested that active stabilization violates the NAR Model Rocket Safety Code - or worse, the law. Neither of those is true. While aiming for a target is against the rules, active stabilization is not. The Signal Avionics isn't a "guidance" system, and can only be used to keep a low to mid power rocket upright in flight. Joe has had discussions on this subject with the leadership of both the National Association of Rocketry and the Tripoli Rocketry Association, and there simply is no safety code or legal violation here. Of course, all other MRSC guidelines should be followed when flying an actively stabilized model rocket, but the homework has been done. Also note, Signal Avionics is not currently available for high power rocketry - baby steps!)

I'm really glad I got to witness a lot of this firsthand. It's been really exciting to see!

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Wednesday, July 26, 2017

Indoor Spray Paint Booth - Success!

I've been too busy lately to write much on this blog, but I have completed the positive pressure spray paint booth video series. Here's the final video.


I've gotten good results finishing several rockets with this booth, all of which I spray painted inside my apartment! A full post on the booth will be written soon.

For the moment, though, I have a lot of stuff to prep for this weekend's launch.

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Monday, July 3, 2017

Modifications to the Indoor Spray Paint Booth


If you saw Part 2, you know that the first version of the indoor, positive pressure spray paint booth was not so great.

But here are the modifications I made.


Not to give spoilers on how the booth turns out, but I just finished another rocket - which I think was made easier with this booth - the Sky Wolf. And I'm pleased with the results.



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Saturday, July 1, 2017

Testing the Indoor Spray Painting Booth


Once I got my indoor, positive-pressure spray paint booth built, it was time to test it out. I started with the white undercoat on the Quest Superbird.

The Superbird is built, and looks great. I am behind on the editing and posting of the video build series of that rocket, but you can see the first several videos here.

After the first test spray, I realized the booth would need a bit of tweaking before I used it again. Here's the video of the first test.


I don't want to give any spoilers, but I will say the kinks did get worked out, as you'll see in the next two videos. The Superbird turned out surprisingly well, considering the trouble I had while building it.


And I've moved on to finish the paint job on the Sky Wolf. Once the decals and rail buttons are on, that rocket will also be ready to go!


Having this booth set up has certainly made it easier for me to get a nice paint job on my rockets, and more convenient for me to paint when I want to. More details - and video - to follow soon!

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Monday, June 26, 2017

Indoor Spray Painting Booth - Sneak Peek


After toying with the idea for a long time, I have built an indoor spray painting booth, so that I can have a place to paint rockets when I want to. The area outside the house in which my apartment is located has little space for spray painting, and the North Atlantic coast tends to be too windy on most days. Good spray painting weather is hard to come by here.

And then there are the stray insects that love to land in fresh wet paint...

I built an indoor booth last year, and while I did get some beautiful paint jobs with it, the design I came up with was potentially dangerous, so I never posted it here.

Finally, I have finished an indoor booth with which I can safely paint inside my apartment. And it's large enough for most projects.

A full build and post will be forthcoming. For now, though, here's Part 1 of the four-part video series I have shot on the booth.

Indoor Spray Painting - Positive Pressure Booth, Part 1


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Tuesday, June 6, 2017

Stability - or - What Happened to Homer's Rocket? (Part 5) - Finding the CP: The Barrowman Equations - Introduction

Illustration from the cover of Centuri TIR-33, by James S. Barrowman

This is a continuation of a series on model rocket stability for beginners. Click here to go to the beginning of the series. Click here to go to the last post.

Each year, since 1958, the National Association of Rocketry holds an event called NARAM - the NAR's Annual Meet. This is a large competition, with fly offs for things like altitude, duration (how long a rocket can stay in the air on a parachute or streamer), scale modeling, craftsmanship, etc.

There's also a Research and Development competition, or R&D. Competitors present research projects into some aspect of model rocketry they've been examining.

Research topics can be very basic or pretty esoteric. They may be focused on a highly technical aspect of rocketry, or perhaps on the craft of rocket building. An R&D project might examine some very specific problem only of interest to competition rocketeers, - for example, the effect of a piston launch pads in altitude competitions, or new exotic building materials for boost wing gliders - while others are more general and concern issues many modelers face.

A rocketeer presents her R&D report.
Image from NAR.org

NAR R&D reports have added much to the knowledge base of model rocketeers and expanded our horizons. While some reports are of interest to only a few people, there are others which really make a large impact on the hobby.

In the next couple of posts, we're going to discuss the one research project that has probably benefited every single rocketeer since it's submission in 1966.

* * *

In the early days of model rocketry, as we've discussed in the previous posts, rocketeers ensured that their designs would be stable by using a somewhat crude but effective method using a two-dimensional cutout drawing of their designs. By balancing the cutout, the center of lateral area could be found, which was also what the center of pressure would be if the rocket were flying at an angle of attack of 90 degrees - sideways into the wind, in other words.

From The Classic Collection by Estes Industries

We also saw hints, through the pictures, that the true center of pressure during flight is in fact far aft of what the cutout method indicated.

But if the cutout method worked, why bother with a different method? It may have been crude, sure, but it worked, and the rockets resulting from its use were stable, so what's the problem? And how do we know where the true Center of Pressure is, anyway?

Well, it turns out that the engine driving the search for a new method of determining CP was competition. Specifically, NAR competition rocketry.

While a model built using the cutout method is certainly stable, it is actually quite unlikely to fly as high as it might. There are three main reasons why: weight, drag, and weathercocking. 

Weight

The cutout method shows the hypothetical center of pressure much further forward than it actually is. In our illustration, using a quickly designed model - Sounder IB - we saw that while the Center of Gravity (CG) was a ahead of the CP in our simulated design and the rocket would therefore be stable, if I'd simply used the cutout method, the CP would have seemed to be so far forward that it was ahead of the CG. If all I had to go on for finding the CP was the cutout method, I'd worry the rocket would be unstable, and I'd have to modify the design.



One way to fix this would be to shift the CG forward, until it was at least one body tube diameter (or caliber) ahead of the CP. To do this, I'd need to add some weight to the nose end of the rocket. I could do this a number of ways. If I had a plastic nose cone, I could stuff it with clay and ram it into place with a dowel rod until the rocket balanced where I wanted it to. (If you have built certain Estes kits, you may be familiar with this method). With a balsa nose cone, I might drill a hole in the shoulder of the nose cone, and fill the hole with either clay or fishing weights, and then some glue to keep everything in place.

With 15 grams of nose weight, the CG shifts forward, but the rocket pays a penalty by losing altitude -
a little over 100 feet. If this were a competition model, those extra feet could make a big difference.

The point is that in order to know my rocket would be stable, I'd have to add a significant amount of weight to the rocket - probably 10 grams or more - and with a rocket as small as Sounder IB, that would add up to a significant weight gain - and altitude loss.

Drag

Another way I might fix Sounder IB's stability problem would be to shift the CP aftward. To do this, I would need to increase the size of the fins. (I could also increase the number of fins, but as we saw with the quickie designs I drew up with the three, four, and six trapezoidal fins, the cutout method might not indicate a change in CP.)

Increasing the size of the fins would, though. I'd have to make a new drawing with larger fins, cut that out, find the new CP, and hope the CG of the finished model would be forward of that.

Increasing the fin span would shift the CP aftward, but the increased
aerodynamic drag would again cost the rocket over 100 feet in altitude.

Using larger fins creates more drag, or wind resistance (as does adding more fins). Drag can be a powerful force which tries to stop a rocket in flight. Because of that, a rocket with larger fins will not fly as high as one with smaller fins.

Weathercocking

All model rockets will tend to arc into the wind somewhat. Some do it only a little, and fly mostly straight until they get near apogee, when the rocket is slowing down, and then arcs into the wind.

Other rockets arc into the wind much more, so that flights are rarely straight up, and more often form a large bow in the sky.

From nakka-rocketry.net

This phenomenon is known as weathercocking, and is caused by the same things which make the rocket stable in the first place.

As a rocket flies upward, its angle of attack is near zero degrees. But in reality, it's never completely zero degrees. Crosswinds flowing parallel to the ground combine with the apparent wind coming directly nose-on to the rocket. If a rocket is flying 200 miles per hour upwards, and the wind is only, say 10 miles per hour from the east, you might think the wind felt by the rocket from the front would overwhelm the wind coming from the side, and the rocket would only experience wind from straight ahead. The rocket may oscillate back and forth as it stabilizes itself, but generally it's only going to feel wind coming from one direction - upwards.

In fact, a consistent, light breeze from one direction will combine with the wind from the front, and as the rocket oscillates back and forth, it will tend to curve into the wind. This happens to some degree with most rockets on most flights. However, it's more apparent on 1) really windy days, or with 2) slow-lifting rockets, or on 3) overstable rockets.

In Part 4, we mentioned that the ideal static margin of stability is 1-2 caliber. A higher caliber of stability is usually OK, but it will lead to more weathercocking. Why?

Think of a rocket as a lever. The Center of Gravity is the fulcrum. The CP is where you grab the lever to do the lifting.

If you have a short lever, it's harder to lift things with it. But a longer distance between your hand and the fulcrum means it takes less force to move the lever.

Archimedes claimed that with a long enough lever and a place to stand, he could move the Earth.

 So a rocket with a longer distance between the CG and CP means it takes a lot less force for the wind at a slight angle of attack to cause the rocket to arc over.

Going by the cutout method, you're going to build a rocket with a much longer lever than you think. You might think you have a 1.5 caliber static margin, but it may in fact be 3 or 4 caliber. You're giving the wind a much easier task of weathercocking the rocket.

And of course, a rocket which expends all its energy in going straight up is going to reach a much higher altitude than one which arcs over into the wind.

Note: While weathercocking is normal in rockets, sometimes it's bad enough that it can be a little scary. The first time I flew my Estes Big Bertha, I was unfamiliar with this concept. The Bertha has very large fins, and it was a pretty windy day. The rocket flew almost horizontally before taking a nose dive - straight at a dog park! Fortunately, the chute opened at the last minute, and the rocket drifted back to the field.

The Bertha is pretty lightweight, and I actually don't think there were any dogs at the park at the time, so it was probably not a dangerous situation - but it certainly scared me at the time! I enjoy looking back at that video now, because my reaction was pretty funny, but I've never posted it online, because in my panic, I used a lot of language.

We'll talk more about weathercocking and how to minimize it in an upcoming post.

* * *

With these limitations, it was clear we needed a better method of reliably finding the CP on a rocket design before building. For competition modelers, this was vital.
One particular section of the National Association of Rocketry - NARHAMS, of Maryland - had a lot of competitive rocketeers. They also had one huge advantage - a particular club member they could turn to to ask for help.



His name was James S. Barrowman. Not only was he a member of the National Association of Rocketry, he also happened to work for NASA, with the sounding rocket program. Perhaps he would be able to help.

We'll talk more about James Barrowman and his solution in the next post.

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Saturday, May 20, 2017

Mega Der Red Max CATO



The weather was great today, and it was really a terrific launch up in Berwick, Maine. But a few of us really had bad luck, myself included.

These pictures are not my rocket. But they are of the rather tragic fate of one CMASS member's beautiful Estes Mega Der Red Max, made even harder to take due to the rocket being out of production, and quite hard to find for a reasonable price these days.


There are CATOs, and then there are CATOs, and this one was quite the CATO.

I ran over to help stomp out burning grass, but those flames had already been taken care of by the time I got over there. While waiting for the water pump to arrive, I decided to snap a few pictures. I knew this had to be captured for posterity.


Despite several attempts to snuff the rocket out on the ground, it kept reigniting, and only water managed to put it out.

It's a sad fate for such a nice rocket, but on the other hand, it did smell amazing - like a campfire using only premium logs.



All my launches went badly to middling today. I didn't have as expensive or irreplaceable loss as this one, but the photos below kind of encapsulate how I felt about my flights.



But my friend Joe did successfully do his Level 1 High Power Rocketry certification flight. And I got to help him prep the rocket for it, so it felt like kind of a success for me. He broke in my new Jolly Logic Chute Release, which of course worked beautifully.

So the day was still mostly good.



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Tuesday, May 16, 2017

See Through Rocket Motor, Part 2

If you saw the video that made the rounds a couple weeks ago of the "see-through" model rocket motor burning in slow motion, you may have noticed that, due to its simply being sliced in two and mounted on a flat piece of acrylic, it didn't burn the way it would if it were intact.

For instance, flame shot out the sides, and the whole propellant grain burned at once, rather than burning from one end to the other.

Well, that YouTuber is back, and here's his latest attempt.

As a member of the National Association of Rocketry, I should say that, for safety, you should definitely not do this at home. Tampering with a black powder model rocket motor in this way can be very dangerous!

But, since someone has done it, at least we can all see what it looks like, and it is fascinating.


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Thursday, May 11, 2017

Using the Kuhn Tube Cutter


The Kuhn tube cutter is a simple tool designed by model rocketeer Howard Kuhn for cleanly cutting paper tubes to a specific length.

I have two of these - a large one I built myself, and a small one from North Coast Rocketry.

I love this tool. I could happily cut tubes all day with this. Here's a video showing how easy it is to cut with this thing.


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Monday, May 8, 2017

New Rocketry YouTube Channel - Ryan's Rocketshop

A 400% upscale Centuri Javelin, posted by Reddit user AscendingNike, who runs today's featured YouTube Channel.

In addition to the new "Featured Vendor" series I recently started, I've been considering a "Featured YouTube Channel" series for a while. There are a lot of great channels devoted solely or mostly to rocketry on YouTube, and I keep finding more.

Today's Featured Channel is a brand new one, and it looks like it's got some potential to be pretty exciting. It's called Ryan's Rocketshop, and can be found here. As of this writing, only two videos have been posted, but Ryan hopes to post a video per week.

The focus of Ryan's Rocketshop is high power rocketry, but from a beginner's perspective. The idea is to follow along with Ryan and learn with him. Even though he's just now getting into HPR, his knowledge and building skills are really impressive, partly gained from building RC airplanes, and likely some time spent building smaller low and mid power rockets.

The first video is the build and test flight of Ryan's Level 1 project, a 400% upscale of the Centuri Javelin model rocket.


Another potentially fun feature is the Rocketshop News. I look forward to more building videos and lots of cool launch videos.


I'm excited about a new channel, especially one that promises to explain things so clearly. I hope to pick up some tips from Ryan. Check it out.

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Saturday, May 6, 2017

North Coast Rocketry SA-14 Archer - Building Up the Tube


The centering rings of the SA-14 Archer fit a little too loosely on the motor tube. The instructions suggested that if that's the case in your kit, you can make the outer diameter of the tube a little larger by wrapping masking tape around it.

The thing is, the centering rings and the fins will be glued to the motor tube, and I have rather cheap, low tack masking tape. I worried that if I did the tape method, it might mean my fins were attached by a rather weak bond.

From Instructables.com

I'd read this post on Instructables.com on how to make your own Kraft paper tubes. As you probably know, Kraft paper is the material most model rocket body tubes and many mid and high power motor tubes are made of, and it's possible to roll your own. Rocket body and motor tubes are just strips of paper, built up layer by layer and glued in place. Enough layers make the tubes strong enough for a high thrust rocket motor.

I decided to try this technique to add a layer or two of paper to the motor tube, making the walls just a bit thicker. With wood glue, the paper would bond to the tube very strongly, and the new paper surface would simply be part of the tube.

Here's how it went:


And here's the finished motor tube.


You can see how solid it is, and even though there are slight surface imperfections, it's quite smooth. If I'd gone too far with the wall thickness, I could now sand the tube down to get just the right fit.

This turned out really great, and I'm glad I thought to try this. Trying it did make me nervous, but it was really much easier than I thought it would be. On more than one occasion, I've wanted to build up a tube or make it a little stronger. Now I have one more technique I can use should the need arise.

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Friday, May 5, 2017

North Coast Rocketry SA-14 Archer - Unboxing


I recently received a little gift - one of the rockets on my wish list - from Matt Steele, of North Coast Rocketry.

North Coast, who make mid power rocket kits and some accessories, is a sponsor of The Rocketry Show podcast, and as part of that sponsorship, Matt sent us some rockets to try out. I've had my eye on an SA-14 Archer for a long time.

I'm doing a video build series on The Rocketry Show's YouTube channel. I started with the following unboxing video. I'm uploading the first build video later tonight, once I'm done editing.

Here's the first video.




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Tuesday, May 2, 2017

Featured Vendor - Aerospace Specialty Products


I needed to stock up on some rocket parts for an upcoming project, and I wasn't sure where to get them. I looked around at various sites, and found pretty much everything I needed, but not necessarily all from the same vendor.

Then, I thought about checking a website I've used once or twice before, and which was great, but which I nonetheless never really thought of mentioning here on the blog.

I went to Aerospace Specialty Products - ASP, for short.

Like a lot of online vendors, ASP sells model rocket kits, parts, building supplies and materials, and recovery devices. But their specialty is scale model rocketry and competition rocketry supplies.

While ASP does sell some of Estes' scale model kits, they have their own line, many of which come in low power and mid power versions.

A good example of this is the D Region Tomahawk, a popular rocket for scale modelers, as it's both striking to look at and relatively simple.

The ASP mid power D Region Tomahawk, over 42 inches tall.
 This is a kit that comes in two versions - a small one one for 13mm mini motors, such as the Estes A3-4T, and one for much larger, 29mm mid and even high power motors.

The mini version of the D Region Tomahawk, just over 11 1/2 inches tall.
A couple of nice features about ASP scale kits is that they are accurate in their proportions, but not heavy on detail. That means that a WAC Corporal or D Region Tomahawk will be shaped like the real thing, but a less experienced modeler won't have to worry about difficult to apply plastic wraps or features. More experienced modelers can add any details they want to - they'll just have to figure out how to do it, something experienced scale modelers enjoy anyway.

ASP sells a few styles of parachutes in nylon and metalized Mylar.

The nylon chutes come in standard rip-stop and "thin mil" varieties, which pack up a lot smaller for fitting into smaller rockets. They're quite colorful.


Mylar "sport chutes" are a bit harder to fold, but they have a couple of advantages. They're very lightweight, and they're so shiny they can help you find a rocket which has gone so high it's out of sight by the time it reaches apogee. The chute will glint in the sun, helping you get your eyes back on the rocket for a successful recovery.

Metalized Mylar "sport chutes" come in silver, red, and purple.
Sport chutes come with everything you need to attach them to a rocket, including a snap swivel, but they do require assembly.

Apart from that, ASP also sells a wide variety of parts, which is what I recently purchased. I needed a lot of stuff to build a small fleet of Flechette rockets for an upcoming project on the blog.


I was also low on centering rings, couplers, and other general rocket building parts. They've got a ton of great stuff, mostly for low and mid power model rocketry, but a few items you might use for high power, such as 38mm motor tubes, plywood centering rings, and even some large cluster centering rings, also made of plywood.


I also have another small payloader project I designed a while ago, and want to get started on, Cassiopeia, for which I needed a balsa transition and some sturdy centering rings.



I placed a large order, and was surprised by how affordable it was. A lot of items on ASP get cheaper if you buy a lot of them.

When you shop around online, you want to consider a number of things. Price is the obvious one, but also shipping. Some vendors will offer free shipping if you order a certain amount of stuff. Others have a flat rate, period. And some calculate the shipping based on the amount of your order, so shipping for a lot of stuff is more expensive.

ASP shipping costs a little more the more you buy, but this is offset by a couple of things - the lower price for buying in bulk I mentioned above, and the fact that the shipping is insured. If you buy things through a site like Amazon.com, whatever you order is guaranteed, meaning even if the post office crushes your package, or delivers it to the wrong address, or if the package gets stolen from your doorstep before you get home, you can get another one or get a refund. Small rocket vendors can't afford to make that guarantee, but the slightly higher cost of shipping means that you some insurance against loss should something happen in transit.

When the box came - only two days after I placed the order - I thought there was a mistake. I had ordered 165 items, but the box was very small.

But I opened it up and realized that everything had been packed with amazing efficiency and care.

I realized after I started unpacking I should have taken a photo, but I couldn't repack this as well as they did.
When you order stuff from a rocketry vendor, the first thing you want to do is unpack everything and verify that everything is there, and that there is no damage. If you do find that something is missing or damaged, don't freak out. Just send an email to the customer service department. You probably got an email confirmation from them about your order, and can reply directly to that email, especially if it's a small vendor like ASP, or JonRocket, or another.

Larger companies, like Estes, have a contact page on their website, and you can contact them through that.

Most model rocket suppliers are small, mom-and-pop operations, and often, the "customer service department" who contacted you is the owner of the company. The rocketry community is a small one, and apart from a few exceptions, you will get excellent service from them. If they make a mistake, just let them know, and they'll often bend over backwards to make it up to you. They will usually ship you a new item, or offer you a refund, or sometimes offer you a credit toward your next purchase, depending on the situation. Once, when I placed a large, many-item order with JonRocket, one or two tubes were missing. It wasn't worth it to me at the time to have them rush ship me a couple of tubes, so they gave me a merchandise credit worth several times the value of the missing items to use on my next purchase.

Here's what I got, neatly packed in layers, from ASP.

Simple payloads for BT-20 rockets.


I ordered four of these for my Flechette project. I need as many as 10 payloads. Some of them I'll make from tubes I already have, but I wanted to take a close look at these and see if I liked them. They include a 2.75 inch red paper tube, a balsa nose block, which is a solid piece acting as a bulkhead between the payload and the inside of the body tube of the rocket, plus a screw eye and snap swivel for attachment of the shock chord and parachute or streamer.

Six more balsa nose blocks or bulkheads.



The original idea was just to purchase these, and use leftover motor tubes from some Estes kits as payload sections. The motor tubes are exactly the same size and diameter as the red tubes in the simple payload kits from ASP, so these should be indistinguishable on the finished rockets.

A BT-55/BT-60 balsa transition.


This is for joining the 1.325 inch diameter airframe of Cassiopeia to the 1.637 inch diameter payload tube (see above design). This is a finely turned piece of balsa, and one of the things that strikes me is the difference between the diameters of the shoulders (the parts that go into the rocket tubes) and the diameters of the two ends of the transition itself. A lot of balsa parts I've used - nose cones and transitions alike - have a much bigger step from the outer diameter of the piece and the diameter of the shoulder. That means that the nose cone or transition is a little too wide for the body tube, so that they don't quite join up. There's a bit of a step from the nose cone or transition onto the body tube, rather than a smooth line. Ideally, for less drag, you want them to match. This transition looks like it should be pretty close, so I won't have much extra sanding to do.

It's lightweight and delicate, and I just love looking at a piece like this one. It always makes me a bit nervous handling a raw piece of turned balsa like this, because it feels so fragile. It feels like it would be so easy to accidentally gouge into it or squeeze it out of shape.

48 1/8 inch launch lugs, 1.25 inches long.


Here, I thought they had made a mistake, but I counted them, and they're all there. I really only need 10 of these for now, for the Flechette project, but they were so cheap when buying in bulk, I decided to get a ton. Now I'm not likely to run out any time soon.

A bunch of centering rings.


40 in total! Some of these will be the thrust rings or engine blocks inside Flechete, most will get used in other projects. I really like the plywood centering rings for BT-50/BT-60. I hadn't seen those before - they're pretty lightweight, but sturdier than fiberboard or card stock rings. Those will get used in something needing a bit more strength - maybe a rebuild of Ceres B.

Ceres B, my hidden camera payload rocket. A sturdy workhorse.
Quick links.


These are for attaching parachutes to mid and high power rockets. You can get them in any hardware store, but most hardware stores in Boston are expensive places with small selection, so I got a few of these through ASP.

Couplers galore!


I got multiple tube couplers for all the Estes-standard tube sizes I use most frequently. Couplers are useful for a lot of things - making longer rockets by joining two or more tubes together, making booster sections for turning single-stage rockets into multi-stage rockets (the coupler gets glued into the booster and is how you join the booster to the rocket), strengthening tubes for cutting or drilling into them (slip a coupler inside where you want to cut or drill, and the tube is less likely to get crushed), even masking off parts for painting (couple a scrap of tube to the rocket you're building, and you can keep all paint out of the motor mount area - very important if you want to attach a booster later!).

I was low on couplers, and they were really cheap. Also, they packed them very well, stacking couplers inside couplers - this is why the box was so small!


165 small items, fast shipping, perfect packing, and not a single counting error - pretty darned good!


ASP will definitely be on my short list of go-to suppliers.

Aerospace Specialty Products - website www.asp-rocketry.com

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