A fun launch!

1 PM Sunday saw me and Duane setting up his canopy at Pegasus East. The day was humid, with intermittent light showers intermixed with a very hot sun, and I sure was not going to sit in my camp chair without something over my head; besides, we needed cover to insure that the rockets and motors didn't get wet. It was our first real launch in months, and nothing was going to stop us from flying a few rockets. Duane had prepped 7 models, I had 4 ready to go, and Vince showed up with 3 of his own - the next couple of hours were going to be filled with rockets taking to the sky and the small clouds of black powder smoke wafting downwind. We also had a couple of spectators - Allen and his friend Laura stopped by the field to watch a few launches. Allen committed a minor sacrilege by bringing a non-flying Lego Saturn to the field, but it was easily forgiven in our zeal to ignite some motors.

A trifecta of Saturn V's launched on Sunday. From left, Duane's (C6-3), Mine (C12-4), Vince's (C6-3)
(Click to enlarge).

First to launch was Duane's 1/200th scale Estes Saturn V on a C6-3. It was a textbook flight, with the parachute deploying at apogee and a gentle landing on the grass. Mine and Vince's Saturns would also make great flights later on, and I must confess I am rather fond of this Estes RTF, which looks great on display and in the air. I highly recommend purchasing one for your fleet.

The America lifts off on a B6-4 (Click to enlarge).

Duane's "Beast" finally gets going on an old Redline
motor (Click to enlarge).

This year's 4th of July rocket, the #1447 Estes America, followed Duane's Saturn V. The A8-3 powered it to just over a couple of hundred feet, where it deployed its 9" nylon parachute for a safe, soft recovery.

Duane loaded his venerable old Geezer TARC "Beast" on the rail we had set up to the east of my tripod pad. This rugged yellow and black rocket was propelled by a much older Aerotech F27-8R Redline manufactured in 2007! As you might expect, this motor huffed and chuffed for several seconds before finally sending the Beast skyward on a nice pillar of red flame. After the chute deployed, Duane remarked that it probably was the best flight he'd seen with this model; I kept my thoughts about being too cheap to get fresh motors to myself. Seriously, Duane inherited a store of old motors and he seems determined to fly them, even if there might be a CATO or two (Most of them just chuff like crazy). I have to admire his guts.

The Beast descending under parachute
(Click to enlarge).

The Rookie's first stage motor ignites
(Click to enlarge).

My Estes ARTF (Almost Ready To Fly) Rookie was next. I had mated it to an Estes booster designed for this class of models, so it flew two stage on a C11-0/B6-4 combination. My HD keychain camera was taped to the side and there was a Altus Metrum Micropeak altimeter tucked inside, so this puppy was instrumented to the max. The flight was good, but Murphy whacked me hard - the Sun was obscured by clouds at launch, making for a very dark video (keychain cams have poor sensitivity), and the altimeter readings were pure nonsense. I think this was the same altimeter that gave bad readings on the SLS test flight several days ago; back then I thought it was because there were no vent holes in the SLS model, but the Rookie had them, so I'm thinking I have a defective altimeter. I will have to contact Altus Metrum and see what can be done about a repair or replacement. Anyway, I did get a nice staging sequence from the camera, so the flight was not a total failure.

Staging sequence from the Rookie onboard camera (Click to enlarge).

Back on the rail pad, Duane had his Estes Trajector ready to go. He must have felt the need for some altitude, for the Aerotech F42-8T put that bird way up there in the highest flight of the day. Allen remarked that it would have probably been wise to have used a Jolly Logic Chute Release, a sentiment I'm sure Duane shared as the Trajector was borne by the wind far away to the northeast, past the tree line and into a soybean field. He was gone quite a while on his search, but came back with the rocket and a few pounds lighter from his trek in the hot Sun.

Duane's Trajector leaves the rail (Click to enlarge).

The last glimpse of Vince's world record attempt rocket
(Click to enlarge).

Vince's first flight was also the only one that resulted in a lost rocket. He had volunteered at the Space and Rocket Center world record attempt, and so acquired a few of the models. This "Guinness Pathfinder" was loaded with an Estes C6, and we never saw it after he pressed the launch button. Our best figuring placed it down near the south edge of the field, but who knows? Vince did take a quick tour of that side, but turned up nothing. I have made a note never to fly my model on a C; heck, I'm not going to use more than A impulse - if I fly it.

Duane readies his Death Star as Allen leaves the area (Click to enlarge).

Duane then flew his Estes Death Star in what was perhaps the most fun flight of the afternoon. The C6-3 took the rocket up to a peak altitude of about 150 feet, whereupon the Death Star broke apart into 4 pieces, each recovered by a bright orange streamer. Allen and Laura were delighted by this model, and Duane certainly enjoys the comments made each time he flies it. I followed the Death Star with a launch of my scratch Probe-18 rocket, loaded with another Micropeak altimeter. The flight was textbook and the altimeter returned good data. So at least one of my Micropeaks work.

The Death Star heads up the rod (Click to enlarge).

My Probe-18 gets going on a B6-4 (Click to enlarge).

Data from the Probe-18 Micropeak altimeter (Click to enlarge).

Vince launched a nicely-built Semroc Recruiter on an Estes A8 - I think he was done with C motors in light rockets for the day. It deployed the parachute near apogee and landed close to the pads, making for a short recovery jaunt. Duane went next with an Odd'l Rockets Birdie, which did what Birdies do - leave the pad fast, turn over, and plop down on the ground. A nice quick flight on an Estes A10.

Vince launches his Recruiter (Click to enlarge).

The blast deflector glows purple under the motor
exhaust of Duane's Geezer TARC rocket
(Click to enlarge).

The last two flights of the day were made by Duane - his red, white, and blue Geezer TARC rocket soared to 501 feet on an F39 composite, and the Chute Release deployed the parachute pretty close to 300 feet (one again wonders why it wasn't in the Trajector?). The very last flight was made by his Cherokee-D, which got decent air on a B6-4. There was a comment or two about a "Cherokee-B", but I couldn't throw shade - a D motor in that bird on that field would have been tantamount to rocket suicide.

Last flight of the day - Duane's Cherokee-D on a B6-4
(Click to enlarge).

Duane recovers a Saturn V (Click to enlarge).

And that, good readers, was the first part of my Sunday afternoon. I must say, it felt great to be flying again!

More about Tuesday...

A friend of mine presented me with one of the rockets used in the 5000 rocket world record attempt on Tuesday - it's the Space Camp rocket, Pathfinder, with special stickers to commemorate the occasion and the sponsors. Pathfinder is BT-20 based, with a red plastic fin can and blue nose cone; this variant not only has the special stickers but the parachute has been replaced by a too-small, 6" long mylar streamer for recovery. It's so short as to be useless - they might as well have just gone with simple nose blow recovery. Anyway, this model has joined my collection, and I thought I'd share some close up pics of it.

A rocket used in the 5000 rocket
Guinness attempt (Click to enlarge).

Close up showing the Guinness decal (Click to enlarge).

Launch lug side of the rocket (Click to enlarge).

In the first image you will notice a coffee stirrer attached to the rocket. This prevented the rocket from twisting around and causing the nozzle to come off the electric match. Without this, there is a non-zero chance the motor would not ignite. Even with it, about 80 rockets (1.6%) failed to leave the pad. The image below shows the rear of one of those - note the scorch mark on the motor, showing the match ignited outside the nozzle.

Hind end of one of the rockets that did not leave the pad showing
the scorching left behind by the electric match (Photo by
Allen Owens - Click to enlarge).

Chuck captured and posted a video of the Saturn V and SLS flights at MSFC. You may hear some colorful language just after the Saturn launch; something stung Chuck on the wrist, and judging from the mark and swelling, it had to have hurt. Unlike me, Chuck doesn't get rattled by such things and he was pretty much back to normal after a few minutes and the application of some sting relief. I would have generated much more drama.


We have scheduled a launch for Sunday, so hopefully I'll get some more flying done then. Stay tuned!

The celebration begins...

Today marked the 50th anniversary of the launch of Apollo 11, the mission that landed the first men on the Moon. Huntsville and Marshall Space Flight Center played a very prominent role in Apollo, as the Saturn V rocket was designed and tested here. So you can imagine that today and the next few days feature many local events to mark the occasion, the first being a new world record attempt at launching the most rockets simultaneously. Stuck at work, I was glued to my computer this morning at 8:32 AM Central Daylight Time, watching the live stream of 5000 rockets powered by Estes 1/2A6-2 motors take to the air. It was most impressive, and the initial numbers indicate that somewhere around 4920 rockets successfully left the pad, with about 44 of these not making it to 100 feet (a requirement of the record attempt). If these numbers hold, then a few weeks from now this launch will be the new record holder, surpassing the previous biggest mass launch by over 600 rockets. Kinda cool.

In case you missed it, here's one of the YouTube videos of the launch:

Loading the rockets on the racks (Photo by Allen Owens - click to enlarge).

After the launch - A pile of rockets!
(Photo by Allen Owens - click to enlarge).

The next event was something in which I was an active participant - the launch of the Estes Saturn V and SLS models kicking off the MSFC celebration. Chuck Pierce and I arrived at the center softball field around 2 PM, and set up a HARA low power rack and hooked up the the controller. 45 minutes later, we launched the Saturn V after a countdown done by a lot of kids from the daycare center. Just like in last week's test flight, the Q-Jet C11-4 powered the model to a respectable altitude, and it deployed the parachute soon after apogee. The breeze - about 10 mph from the SSW - carried it out of the field over into a nearby parking lot, where it was recovered by a fireman (on standby if the launch should start a fire). No damage, so I was happy. Flight #2 on my Saturn V complete.

My Estes Saturn V kicks off the MSFC Apollo 11 celebration (Click to enlarge).

The SLS was launched next. As you can see from the image, the Estes C6-3 motor seemed to produce a lot of flame on lift off, enough to burn through half of one of the black fins. I'm pretty sure some of this was caused by the model being too close to the flat metal blast deflector, which probably directed the exhaust onto the fin. However, the motor still looked a little "hot" to me - still scratching my head a bit over this one. The SLS put in a good flight, deploying its parachute right at apogee and landing just on the edge of the softball field. But the post flight inspection of the rocket showed not only the damaged fin but also no nose cone; it had separated from the clear plastic base either at ejection or upon hitting the ground. A quick search of the area turned up nothing, so I suppose you could say that the launch was successful, but we lost the crew on landing.

The SLS heads up the rod - look at the motor exhaust from the C6-3! (Click to enlarge)

After the MSFC launch, Chuck dropped me off at the newly mowed field across the street from our old launch area (I think I will call it "Pegasus East"). Here Vince and some of the Hope Rising rocket kids were flying models as part of the Space and Rocket Center's Global Rocket Launch. Vince launched his 1/200th scale Saturn twice, both times on C6-3's, and the Hope Rising students put up BMS school rockets on A motors, with everything recorded by the cameras of a visiting Japanese documentary crew. All flights were good, with nary a CATO or failed recovery. Being old, fat, and very hot, I sat in a camp chair and provided commentary - something I am very skilled at.

Vince in full NAR regalia; behind him, a student and Constance begin to load a
rocket on his very robust pad, built on a telescope tripod (Click to enlarge).

A School Rocket takes to the sky (Click to enlarge).

The documentary crew at work (Photo by
ChrisAnn Driskill - Click to enlarge)

Saturn V flown, Apollo 11 launch commemorated - Good way to start off marking the 50th anniversary of the first steps on the Moon.

Test flights...

Monday was test flight day, so 4 PM found me - along with Allen, Duane and a few friends from MSFC - at the field across the street from our old launch site. It was very, very hot - the area was under a heat advisory, with feels like temps over 102 degrees - so I did not dawdle setting up the pad and controller. I had already prepped the rockets (sans igniters) the night before, so I expected things to go quickly - which would be good, as I wanted to get back into a place with some air conditioning.

Estes 1/200th scale Saturn V on a C12-4 (Click to enlarge).

First up was the Estes Saturn V, flying on a Quest QJet C12-4. I had a little trouble getting the igniter to stay in place - I'm still new to using these composite motors, and after trying various sizes of Estes igniter plugs, I finally settled on using good old masking tape, which worked fabulously. The Saturn rode a trail of thick black smoke up to 394 feet; I held my breath, waiting for the parachute deployment, which occurred well past apogee. Fortunately, the shock cord held, and even better, the Saturn missed hanging up in a tree near the road. A successful flight!

I had equipped all of the rockets with small altimeters, knowing full well I could get crap readings given the lack of vent holes in the models. But I figured nothing ventured, nothing gained, and the very small additional weight would not impact flight performance. So the Saturn and SLS rockets had Altus Metrum Micropeak altimeters and the Saturn 1B contained a Perfectflight Firefly. The Saturn V altimeter was the only one that returned usable data; the SLS Micropeak readings were a bunch of crap, and dumb me forgot to turn on the Firefly in the 1B (still kicking myself over this, but hey, I wanted to get out of the heat).

Saturn V Micropeak altimeter readings(Click to enlarge).

Next up was the SLS, loaded with an Estes C6-3. We adjusted the rod angle a bit to avoid the trees near the road and gave the count. The SLS rose into the blue sky, reaching a respectable altitude and deploying its parachute just past apogee - a very nice flight! I must express my thanks to Allen, who braved bugs and who-knows-what-else recovering the rocket from the knee-high weeds.

The Estes-built 1/200th scale SLS lifts off on a C6-3
(Click to enlarge).

Last to fly was my grizzled old Cox Saturn 1B. It blasted off on an Aerotech D10-3, which chuffed a bit before propelling the rocket skyward on a streak of white fire (I love the White Lightning motors!). The 1B achieved the highest altitude of the day, but the ejection charge rammed the parachute up into the hollow capsule/LEM adapter, which kept it from opening. I watched in horror as the model fell to the ground, hitting near the edge of the weeds with a thump. Fortunately, there was very little damage - the escape tower had broken off and was missing, but the rest of the model was intact. She will fly again, as soon as I can figure out how to make or get a new escape tower.

My Saturn 1B on an Aerotech D10-3 (Click to enlarge).

Test flights complete - we are now ready to launch the Saturn V and the SLS at MSFC's Apollo 50th celebration on July 16.

Rocket science...

My place of work, Marshall Space Flight Center, is hosting a series of employee events to mark the Apollo 11 50th anniversary on July 16. One of these will be a launch involving the Estes 1/200th scale Saturn V and a custom SLS (also built by Estes) of the same scale. My job is to work with Chuck and the Public Affairs people to get everything tested and ready so that our center director can press the fire button. I'm rather enjoying it, especially given that the test flights are coming up early next week. Have to make sure we have the right motors and the birds fly straight - Redstone Arsenal insists we keep the peak altitudes low, and an unstable flight would pose a risk to the onlookers. So we test.

Estes custom SLS and Saturn V rtf - 1/200th scale (Click to enlarge).

But a few calculations are needed before the test.

As mentioned in a previous post, the only recommended motor for the Estes Saturn V is the C6-3. However, the liftoff weight of the model is 172 grams (6.1 ounces), well above the maximum recommended weight of 113 grams (4 ounces). This is not a good situation, and the Internet has many accounts of the model achieving a very low altitude and ejecting the parachute well past apogee. But there are other 18mm C and D motors available - do they provide a more acceptable performance?

Reproducing the rocket in Rocksim or OpenRocket would have taken a lot of time, so I resorted to using an app I have on my iPhone (RocketCalc) with inputs from my measurements (weight, maximum diameter) and Thrustcurve.org (which also has an app). I also used an online descent rate calculator to check the descent rates to make sure they were slow enough to avoid damaging the model. The results for the Saturn V are below - note that the C6-3 gives a thrust-to-weight that is way too low (should be around 5) and that the burnout velocity is under 100 feet per second. Maximum altitude is only 200 feet. Easy to see why this motor produces flights that are nail-biters. The next motor, the Quest C12-4, produces a decent thrust-to-weight, burnout speed, and altitude, but the delay is about 1.8 seconds too long (4 versus 2.2 seconds to apogee). This means the parachute will deploy after the rocket has fallen 52 feet from its peak, where its speed is a fast 58 feet per second - quite a stress on the shock cord and attach points! The best motor choice is the Aerotech D10-3W, but the projected 651 foot altitude blows right through the ceiling imposed by the Arsenal, so it's out. The Quest D16-4 also has some good numbers, but the delay is too long, by the same amount as for the C12. The irony here is that the C6-3 is the best choice as far as delay, but the other numbers suck bad. Also, the reports out there in the wild mostly state that ejection was well past apogee, which flies in the face of these calculations.

Performance calculations for the Estes 1/200th scale Saturn V (Click to enlarge).

Which is why we are going to test - with a C12-4. I'm hoping she stays together.

I repeated the calculations for the Estes-built SLS, first calculating an effective diameter from the sum of the frontal areas of a BT-60 and 2 BT-20s (49 mm). It's lighter than the Saturn, and here the C6-3 is the right choice. The thrust-to-weight is a little low, but the altitude is comparable to that of the Saturn on a C12 and the delay is good.

Performance calculations for the Estes custom 1/200th scale SLS (Click to enlarge).

And while I was at it, I ran the numbers for my repaired Cox Saturn 1B, which is the pig of the three. Even though it won't fly at the MSFC event, I will probably launch it during the testing of the other two models. Since I won't be restricted in altitude, the D10-3W is the obvious choice here.

Performance calculations for the Cox 1/125th scale Saturn 1B (Click to enlarge).

Motor choices made - here's hoping for good testing weather!

This year's 4th of July rocket

Every year I try to build a rocket in commemoration of the 4th of July. This year's choice was a simple model - the rocket from the Estes #1447 America starter set, which features the plastic fin can used in the Estes Generic rocket (except that it's black). Naturally the build took a few days, as I had to fill the body tube spirals, after which came primer and white paint. Like many modern kits, it lacked waterslide decals, coming with only "peel n' cuss" stickers. It's also not red, white, and blue, but I figured it had the right name and it does proudly sport "USA" in big letters.

The America starter set in the 1994 Estes catalog (Click to enlarge).

 The America set was available from 1993-1994, and you can still find quite a few of them (along with the rockets in bulk packaging) on eBay. A lot of sellers confuse this rocket with the Estes Athena, which was available at the same time. So you will notice a lot of America rockets listed as Athenas, which confuses me, as the Athena had a silver nose, white fins, and blue/silver decals - very similar design, but totally different decor.

The Athena in the 1994 Estes catalog (Click to enlarge).

Anyway, here's this year's 4th of July rocket. Welcome to the fleet, America!

#1447 America (Click to enlarge).