Saturday, May 31, 2014

For the 4th

Every year I build a USA-themed rocket for the 4th of July - the Estes Liberty, Citation Patriot, and Yankee have been the recent constructs. While sealing the fins of the Hen Grenade (I have done a LOT of sanding this weekend), I gave some thought to this year's 4th special. What would it be? I considered the Estes Big Yank, but it is just a longer Yankee, and there was the entendre behind the name that bothered me. Custom Rockets has their Liberty, but I hate the peel and cuss stickers that come with those kits. However, I gave it serious consideration, figuring I could laser print some nice water slide decals to substitute for the stickers. Then I realized I had been staring at the answer all along - for years in fact.

The Centuri Screaming Eagle's first appearance in the 1973 catalog. I recently
acquired a Powr Pad from Ebay; can't wait to launch my Eagle from it!
First appearing in 1973, the Centuri Screaming Eagle was part of that company's line up for 10 years, right up to Centuri's end in 1983. It was a perfect rocket for impatient youths like myself, featuring a plastic fin can which enabled the rocket to be assembled in about 20 minutes. I owned several, and can testify that you could be flying less than an hour after opening the bag. The red, white, and blue decor and chrome decals were quite distinctive; no paint was required to get a fairly nice looking rocket. All you had to do was get the stickers on straight - which I often didn't. The rocket was practically indestructible; even a catastrophic no parachute lawn dart still meant you would be able to salvage the plastic nose cone and fin can. Glue on another body tube, and you were ready to fly once more. That indestructibility provided the answer to this year's 4th of July conundrum, as there was a 35 year old Screaming Eagle fin can sitting on the corner of my work table.

A couple of hours soaking in warm water got rid of the decomposing decals still on the fin can. However, nothing I tried could remove the old, rock-hard glue at the top of the unit. This put the kibosh on using the fin can in my clone; hopefully someone can provide a technique that will remove the glue for a future build. During a break to watch some 1950's science fiction B movies ("At World's End", "From the Earth to the Moon"), I realized that it would not be too difficult to clone the fin can using Semroc tubes and 1/16" basswood for the fins. The fin pattern was available on Jimz's web site, though I could have easily created one by simply measuring the dimensions of those on my unit. I set to work, assembling the motor mount and cutting out the fins. The pic below shows where things stand at present - I am about to glue on the fins while I watch "Munster Go Home" on Svengoolie.

Old Screaming Eagle fin can at right; basswood fins and lower tube/motor mount to its
left. Hen Grenade nose cone and payload section parts are in the background.
Shouldn't take too long to finish this one. It will be nice to have a Screaming Eagle back in the fleet!

Wednesday, May 28, 2014

Rocket history trivia

First rocket "kit"was Orville Carlisle's (NAR #1) Rock-A-Chute Mark II, produced in 1957.

The 18x70 mm motor size of common A, B, and C motors today came about because it was the same size tube used by the "Buzz Bomb Helicopter" firework made by Brown Manufacturing, which produced the initial rocket motors for Model Missiles Inc (MMI), the first rocket company. Convenience dictated the size. This was also true of the 29mm diameter used in many of today's mid power motors. Our hobby borrowed from the fireworks industry, a fact often overlooked in this more safety conscious time.

The first rocket motors were of one type, equivalent to an A4 in today's classification. Only way to get more power was to cluster. The familiar Estes BT-60 body tube used in the Big Bertha, Ranger, Mean Machine, and many other kits came about because it was realized that you could fit 3 18 mm motors in a paper tower tube. A "rocket version" of these tubes was quickly produced.

The Model Missile Association was established on December 7, 1957. It was a non-profit Colorado organization, and became the National Association of Rocketry at the end of 1958.

Advertisement featuring the MMI Aerobee Hi
Model Missiles Inc produced the first mass-produced model rocket kit, the Aerobee Hi, in 1958. Vern Estes, founder of Estes Industries, got his start in rocketry by creating Mabel, the first rocket motor making machine. Mabel I (there were several Mabels) could produce a motor every 5.5 seconds. Estes made the motors for MMI, but he soon outpaced demand and created Estes Industries to sell the surplus motors. The first Estes kit, the Scout, came out in 1961.

NARAM 1, the first NAR rocket competition was held at the "Hogback Rocket Range" in Colorado on July 16 of 1959. Norman Mains, Jr. scored the most points and was the first national champion. NARAM 1 also featured the launch of a 7 engine cluster, "Honest Ivan" - a very impressive feat for back then. I love the cool launch towers they used (see image below) - I wish I had the skill to make one!

A few little known facts from the origin of the hobby...

Monday, May 26, 2014

A long delayed build

Ever since the early 1960's, Estes has dominated model rocketry - it is almost synonymous with the hobby itself. A few old timers fondly remember Centuri Engineering, noted for its exotic designs; little more than handful remember the smaller companies, such as FSI (Flight Systems Incorporated), Canaroc, RDC (Rocket Development Corporation), Competition Model Rocketry (CMR), Vashon, and others. Though they are mostly forgotten, these companies made valuable contributions to the hobby, often showing a level of innovation far beyond the Estes and Centuri offerings. For example, RDC produced the first composite motors, from which high power rocketry began. FSI made the first kit capable of breaking Mach 1, and Vashon came out with an innovative (albeit short-lived) line of freon powered rockets. These companies also had some pretty awesome designs - you can browse some of the old catalogs at Ninfinger's site.

A few years back I was doing just that, and ran across the Space Age Industries (SAI) catalog. I love egg lofters - egg lofting events are one of my favorite competition events. They pose a decent design/build challenge, and the potential for a catastrophic mess is high :) Anyway, this page in the catalog caught my eye:

Page from Space Age Industries catalog, published circa 1969
Who could resist an egg lofter with egg shaped fin tips and a name like "Hen Grenade"? I couldn't, so I set to searching for the plans on the Internet. I found them at Ye Olde Rocket Plans, and gleefully realized that Semroc had the body tube size I needed (ST-18), along with the motor tube and centering rings. The nose cone was trickier, as I had no idea what the fiber material mentioned in the instructions was; besides I suck at making such things, and trembled at the thought of my improvised handiwork successfully containing an egg throughout a rocket flight. Fortunately, an alternative existed in my friend Gordon, "The Sandman", owner of Excelsior Rocketry. I put in an order for a custom part, and he fashioned this beautiful balsa nose:

 Gorgeous Hen Grenade nose cone fashioned by Gordon Agnello at Excelsior Rocketry.
With all the parts assembled, it was time to start the build. After I dutifully entered the Hen Grenade's name into my "Under construction" list on Ye Old Rocket Forum (YORF), I set out to cut the fins, knowing that the egg shaped tips were going to be a challenge with a hobby knife. This proved to be truer than I reckoned; I ended up giving up after several attempts that resulted in cut fingers and some blood loss. Deciding to wait until my skills at balsa cutting improved (and out of a sense of self preservation), I set the Hen Grenade parts up on a shelf, where they sat for years.

And where they would be setting still, if it were not for Gordon. I had ordered some decals for my Mean Machine clone (the topic of my "Bad Boy of Yesteryear" post), and Gordy, tired of seeing the Hen Grenade still in my "Under construction" list after a couple of years, sent along a fin set that he manufactured with his tools. The removal of the possibility of mutilation rekindled my desire to build this bird, and so construction has begun. I should have it ready to fly by Southern Thunder, and am excited about seeing this grand old design fly once more.

That, and the appeal of getting my fellow YORF'ers off my back…

Saturday, May 24, 2014

Saturday afternoon launch

Last night was the Camelopardalid meteor shower; this morning I woke up to find Lake Erie in my bathroom. The new neighbors accidentally broke a water pipe while installing a washing machine, and the resulting flood made its way into my apartment. Fortunately, Rocket City Carpet came to the rescue - the water is gone, but I have to put up with 5 big blowers for the next few days. However, meteor showers and rising water were not sufficient to deter me from launching rockets with Duane, Nate, and a couple of Nate's kids today.

We arrived at the horse farm a little before 2 PM and set up the range. Duane had quite a complement of pads (2 LPR and 1 rail); I added a second launch controller to the range. My rocket choices for the day were my Centuri Thunder Roc clone, my Estes Stormcaster, and the ever reliable Der Red Max. Duane had a nice assortment - a mini-engine powered Birdie, a Semroc Scout, a Cherokee-D, and a green mid power scratch build. Nate brought nuthin' - he took it easy and watched the show. As he is a teacher, I cut him some slack; anyone who puts up with middle schoolers day after day deserves to kick back. However, I expect to see some rockets out of him next launch!

We launched at a leisurely pace. Duane kicked things off with the Birdie on an A10-3T motor. I followed with my Thunder Roc on an E9-6. It got some nice altitude, but broke a fin even though the parachute deployed nicely. Easily repairable. One of Nate's students, Zac, followed with a pink(!) Mean Machine on a D12 - it would fly a couple of more times despite a crumpled body tube section down near the fins. Duane tried launching his green scratch build on a G-80. I say "tried" because the rocket didn't leave the pad - a malfunctioning motor produced only an ejection charge, popping the parachute just like the famous Vanguard rocket from the late 1950's. My Hero 3 caught it all in stunning HD:

Next up was my Stormcaster on a C11-5. I set up both the Hero 3 and a keychain camera to obtain video from both the ground and the rocket. Here's the onboard video:

As you can tell from the video, the descent was a bit on the fast side, due to a partial chute deployment. The rocket landed hard and cracked two fin fillets. Repairable, but a little paint touchup will be required. Following my usual practice, I later looked through the video and extracted the interesting frames - 3 are shown below:
A "sparkly" ejection charge

One of the horse barns

Mr. Pahman in his lounge chair
And here's the view from the Hero camera at 100 fps. It will play at 1/3 real time.

Duane's Cherokee-D followed my Stormcaster, flying on a B6-4. I love the Cherokee-D; it's a classic design and every rocketeer should have one in his or her fleet. The Hero 3 caught this beauty leaving the pad:

My Der Red Max followed the Cherokee-D. It flew flawlessly on a B6-4 motor, landing softly in the grass. It has the distinction of being the only one of my three rockets to emerged unscathed from today's launch. Duane followed with another launch of his Cherokee-D on a C6-5, then the Semroc Scout on an A8-3.

The last launches of the day involved two unpainted Mean Machines brought by another of Nate's students. One did the classic core sample when the parachute failed to deploy (It seems a lot of Nate's kids did not glue the body tube segments together, allowing them to slide freely on the couplers. I blame the crappy instructions that come with most Estes kits these days.) and the flight involving a two segment Mean Machine (An "Annoyed Machine"?) ended with the bird hung in the rocket eating trees to the East.

We left the field right at 4 PM, sated with two hours of fine rocketry. I will end this post with a frame from the video showing Duane's Cherokee-D leaving the pad.

Wednesday, May 14, 2014

Mountain top launch

This morning, my club president, Dan Cavender, and I made the trek up Monte Sano mountain to Monte Sano Elementary. It's their Space Week, and we were scheduled to give a rocket talk and launch demo to the kiddos. I thought we were going to be dealing with a group or two of K-2nd graders, but it turns out we had four groups - 2nd, 3rd, 4th, and 5th grades. Dan is a high power guy - a darn good one at that - so I bought along 3 of my rockets to fly in the very limited clear grassy area at the school (Monte Sano has beaucoup de trees). Unfortunately, I had only packed 3 motors for the demo - an A10-3T for the Birdie, an A8-3 for Der Red Max, and a C6-3 for my Estes Snitch Saucer - so we had to combine the 2nd and 3rd graders into one group. That way, one rocket flew for each gathering of kids.

Dan explains the basics of rocketry to Monte Sano 4th graders
Today Dan did most of the talking - he showed the HARA launch videos on Youtube to give a flavor of our Manchester launches, showed off his gorgeous Pegasus HPR scale model, and discussed the basic parts of a rocket, asking the kids about each part (nose cone, air frame, and fins). I served as the launch guy, setting up my pad and controller, and doing the final prep on the rockets before flight. I also brought along my Hero 3 camera to see what sort of video I could obtain of the rocket flights from the ground - at 100 frames per second, no less :)

The Snitch was launched for the 5th graders - it flew to about 70 feet or so, landing right beside the school building. One rocket launched, one rocket recovered. Der Red Max flew for the 4th graders; it was the one I was almost sure would hang in a tree, as it returned via parachute. Fortunately, the wind was calm and the rocket missed the trees by a few yards. Two rockets launched and recovered. Last up was my flying badminton birdie, which had the best altitude of the three flights on its A10 motor. It too landed right beside the school, making for 3 perfect flights.

The Go Pro Hero was easy to operate using my iPhone. I managed to get it pointed so that it got some launch video looking "up the tail pipe". The day was cloudy, so the vids were a bit dark; I was pleased nonetheless.

Here is a 1/3rd real time movie of the Snitch leaving the pad, created from the 100 fps footage:

and this is the real time footage of the Der Red Max flight. I love the kids' enthusiasm, and was amused by their reaction when the ejection charge fired. Even though it looks like the rocket was heading for the tree on the right, it missed it.

The rain moved in soon after the Birdie launch; it was a good thing our stuff was scheduled for the morning! Next year I will bring more motors along so I can fly for each individual grade. Of course, I will probably hang one or more in a tree then, given the perversity of Mother Nature.

Saturday, May 10, 2014

The 2015 TARC competition rules are out

Today saw the TARC National competition up in Virginia. The Falcon Rocketeers were there representing Huntsville; I understand their first flight went well (12 score), which got them into the final flyoff. Unfortunately, a cracked egg DQ'd the flight, which dropped them out of the money. Sorry about the egg, but great job this year, Falcon! You guys did Huntsville proud!

Today also had a surprise - the release of the rules for the 2015 TARC contest; normally these do not come out until July. I guess they want to give the teams a head start given that they are keeping the 2014 scoring scheme of summing the two best qualification flights. In 2013 and before, it was a TARC team's best score that counted in the selection for Nationals; this new scheme eliminates the "lucky shot" that helped the, um, less polished teams make it to the top 100, and emphasizes consistency. Summing the two scores, combined with flying two eggs, made 2014 the toughest TARC year I can recall. So what about 2015?

Here is a summary of the new rules:

1) Rocket must hit an altitude of 800 feet, and the payload section must land safely within 46-48 seconds from the time of first motion on the pad.

2) The payload section containing the egg and altimeter must come down separately from the rocket. It must use a single parachute, and as before, the egg must not crack or break on landing. The payload section must be returned to the NAR official monitoring the qualification flight. The rocket body and motor must descend in a safe manner.

3) The rocket must be longer than 25.6 inches (650 mm) in length, and may use any motor or combination of motors of F impulse (80 N-sec) or lower. It may not weigh more than 650 grams at liftoff.

4) Teams get 3 qualification flights.

I guess I had better get working on a design - can't let the kiddos have all the fun. This looks easier than 2014, but who knows?

Saturday, May 3, 2014

The Bad Boy of Yesteryear

Now that the RX-7 and the Thunder Hawk are in primer, it is time to start another build. The choice was easy; Nate has purchased for his Liberty Middle TARC team a bunch of Estes Mean Machines for building and flying later this month. He also is working on one for himself, and I did not want to be left out of the crowd. So I started work on my Mean Machine clone today.

First appearance of the Mean Machine in the Estes 1978 catalog (click to
As you can tell from the above catalog page, the Mean Machine made its first appearance back in 1978. Back then, there were no 12 foot tall, 6 inch diameter high power rockets - the Mean Machine, 6 and a half feet in length, was Da Man, drawing ooohs and aaahs whenever it showed up at a launch. This rocket could soar to a respectable 400 feet on a D-12 motor, provided you remembered to weigh down your Porta Pad launch pad with bricks. I can recall quite a few Mean Machines toppling unceremoniously to the ground in the slightest breeze, crumpling the upper part of the body tube.

Note that the lettering and fin decals are white in the catalog; this held true until 1993, when the Mean Machine decals changed to a blue color, which lasted until 2005, when the kit was dropped from the Estes lineup. It reappeared in 2007, this time sporting yellow decals. The rocket has retained its black paint job ever since 1978, which I reckon is supposed to convey a sense of badness. Alas, the kit is not in this year's Estes catalog, indicating it is once again out of production. Fortunately there are enough around that you can still find them in hobby shops and online vendors.

Updated Estes Mean Machine
I have owned a couple of Mean Machines during the course of my rocketry career. All flew beautifully, with nary a crash (which is rare for my birds). They were done in by a simple design flaw - the Mean Machine consisted of 4 18" body tubes glued together using couplers, with the parachute ejecting up at the nose. This meant that you had to find a way to get this over 6 foot rocket into a car without crunching or bending it; not very easy, especially if you were a generally careless teenager. My Mean Machines met their fate in the mad rushes to load up rockets before the rain started or summer band practice; ignominious ends to fine missiles who should have died the fiery or ballistic deaths reserved for rockets. My clone will split in the middle to avoid the vehicle catastrophes of the past, and Estes fixed the problem as well - starting in 2007, the Mean Machine was provided with a coupler that enabled the rocket to be split in two for transport. It also got a longer motor mount to handle E motors, which my clone will also feature. My version will also have the white decals and an ejection baffle to eliminate the need for chute wadding.

Today I cut out and sanded the fins, built the motor mount and baffle, and filled the spirals in the lower body tube. A Big Bad is on its way to join my fleet!

Friday, May 2, 2014

Launch at the 4H Urban Farm Day

This afternoon Vince and I made the trek to the agricultural center at Alabama A&M to launch a few rockets for the kids at the 4H Urban Farm Day. The weather was nice and sunny, which meant that we would actually be able to launch a few rockets today; the first time we were asked to participate in this event was during the great tornado outbreak in late April of 2011 (which cancelled the event, obviously), and it has seen rain every year since. In 2012 and 2013, we were forced to do indoor dog-and-pony shows, which were less inspiring and interesting to the kiddos. Today rockets would fly, much to the delight of the couple hundred school children watching.

Some of the kids anxiously awaiting the launch of the first rocket.
8 is becoming the number for these demos, as Vince and I each prepped 4 birds for flight. Vince had an adopted tube fin rocket, an small Estes rocket from the 1990's (seen in the pic below), some other rocket which I do not remember, and an Estes Silver Comet, which flew on a D motor. It's terrible getting old - I have enough trouble keeping track of the rockets I fly, much less those of others. My apologies to Vince; I should have taken notes on my phone. I brought an Estes Snitch saucer (C6-3 motor), an Estes Pulsar Pink Crayon rocket (C6-3 motor), an old Estes Der Red Max (B6-4 motor), and my Deuce's Wild, which flew on two B6-4's.

Vince hooks up a rocket on his Porta Pad; my Pulsar Pink Crayon rocket
is at right.
Following the pattern established a couple of weeks ago at Horizon Elementary, we alternated flights. My crayon was first, and despite the breeze, it landed relatively close to the pad. Vince followed with the small Estes rocket in the above picture; it too did not drift as far as I had originally reckoned. One of the adults and a couple of young ladies had no trouble retrieving any of the rockets we launched this day, and I am very grateful to them for enabling us to focus on putting the rockets in the air. The only "interesting" flights today belonged to Vince - the hand-me-down tube fin rocket went unstable on the C motor, lawn darting into the soft ground, and his Silver Comet had the nose cone separate. Fortunately, both pieces were recovered, so no issue as far as returning it to flight (parts for the Silver Comet are hard to find, especially the custom plastic nose).

I ended the launch with my Deuce's Wild on 2 B motors. I had taped one of the keychain cameras to the rocket's body, capturing the video below. It is pretty normal, except that if you look closely, you can see the parachute wadding (flameproof toilet paper used to protect the parachute from the hot ejection charge particles) whiz by and fall toward the ground below. You can also faintly hear the kids cheering throughout the flight - again, got to love that enthusiasm!

The animated gif below shows the sequence with the chute wadding slowed down to 3 frames per second - it's quite neat, actually.

Parachute wadding falling away from the Deuce's Wild (Click to enlarge)

8 launches, no rockets lost, and a free BBQ sandwich for lunch… A pretty decent couple of hours!