Amateur Rocketry

Sac Arrow

Sac Arrow

Touchdown! Greaser!
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Snorting his way across the USA
I guess it's aviation. I don't know, are rockets aviation? Close enough. Most of us have played around with Estes kits (hecka fun!) but some of these are truly bad ass. The Karman line begins 100 KM above the earth, and is the de-facto standard for when outer space begins. Some amateur rockets have been able to reach it. This one comes pretty close.

 
Serious question: do these things get notam’d or is it just big sky theory?
 
Very cool. I remember following the Civilian Space Exploration team's amateur rocket when it became the first to pass the Karman line in 2004. https://en.wikipedia.org/wiki/Civilian_Space_eXploration_Team.

I started, like so many, with model rocketry when I was a kid, then when I got back into it as an adult the hobby got a little out of hand, as I moved first into mid-power rockets, then high power. Nothing nearly as beastly as the big amateur rockets though. The 3 largest rockets in the picture are Level 2 high power rockets (engines J, K, L, following the same system as the Estes A, B, C, where each letter roughly doubles the impulse of the letter before). Those rockets are 4-6" diameter, and 4 to 8' long, flying altimeters and electronically-deployed parachutes. The little orange rocket up top, next to the flying Easter egg, is a Machbuster, built from a kit designed to do exactly that. It broke the sound barrier (not very impressive, they're not big enough to generate much of a shock wave) and also broke a mile in altitude. It was so hard to find afterwards that I never flew it again.

The rocketry club, flying from a huge sod farm near Warwick, New York, has a monthly FAA waiver for flights up to 4500' AGL. They used to be able to open temporary flight windows up to 18,000 AGL, but no more...

IMG_1459.jpeg
 
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Incredible! I want to see one of these things launch inperson.
 
TCABM said:
Serious question: do these things get notam’d or is it just big sky theory?
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They get notam'd. IIRC some of them are stabilized to help beat down the amount of trajectory uncertainty.
 
These guys shoot rockets every year in south central KS.

The one launching around the 5:15 mark was planned to reach 40,000'

This is video 1 of 4(?)

 
Sac Arrow said:
I guess it's aviation. I don't know, are rockets aviation? Close enough. Most of us have played around with Estes kits (hecka fun!) but some of these are truly bad ***. The Karman line begins 100 KM above the earth, and is the de-facto standard for when outer space begins. Some amateur rockets have been able to reach it. This one comes pretty close.

Click to expand...

I lived in northern Illinois during the earlier part of my rocketry years, and one of the hazards was rocket-eating trees, Illinois being fairly verdant. I never understood how it was anyone ever held onto their higher altitude rockets, mine were good for a few launches and then disappeared into the landscape. A good 20 years after that I was riding my Honda NT650 to Atlanta from Alberta, and was passing through central Colorado on US 50, when I passed the Estes main office in Penrose, and at that moment I understood where they were coming from:

Estes%2BAerial%2BView%2BB.JPG


Yeah, a rocket could go a long way from the launcher and you could still find it out there.
 
We get a notam every couple months on the north side of town here for model rocket launches surface to....I think it's 4 or 5 thousand. Seems like they're always landing 14 on those days and approach brings me in right over it. Haven't been hit yet. Pretty sure "see & avoid" would be worthless though.
 
I'm single and I suspect these guys are as well because I can't imagine any significant other loaning their kitchen aid to mix rocket propellant.
 
Racerx said:
I'm single and I suspect these guys are as well because I can't imagine any significant other loaning their kitchen aid to mix rocket propellant.
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I totally would. But I'd make sure he understood he was cleaning it up really well after using it. :cool:
 
Back in another board, a question was raised - how practical was it to launch a small object into outer space via amateur rocketry? (Answer, not very - theoretically possible but it's still going to cost about as much as a SpaceX.)

Here is another example. This one actually did get past the Karman line.

In the original link I posted, we are looking at a very well engineered amateur rocket project with a budget that was likely in the tens of thousands of dollars. The above rocket represents a well funded project hosted by a major university that probably had a budget of well in to the hundreds of thousands of dollars. Maybe even over $1M if you look at all the machinery involved. It's significantly larger, more expensive, and it really didn't go that much higher.

I would say the engineering of the first example was probably better. Towards the very end of the second video, when they recovered the booster, I had a hard time telling but it looks like they may of had a partial in-flight delam of the carbon fiber fins, which probably cost them a significant penalty in altitude.
 
That was an impressive feat, even considering the financial resources and labs available.

On the other hand, the unprotected students at the launch scares me. I am sure that they had a chemical formula that had a near zero likelihood of explosion, but with that high an energy content, there is no zero possibility.

My brother and I launched a number of rockets with home made fuel, and bodies. All went well until the last one. It blew in the launch guides, and destroyed them. We were protected by feet of earth, ignition was electric. We were willing to give up the thrill of seeing the launch, settling for the flight after reaching a hundred feet or so, after the rocket had reached speeds that assured stability from the fins. Before the first second, without fin stability, a turn to horizontal was no danger, as we were down 5 feet below ground level, but had an open view up.

Our explosion occurred at about one foot of motion. No fragments were recovered beyond one fin. There was a modest hole in the ground, which contained no fragments. This launch area was lawn mowed grass, and we searched 50 to 100 feet, and that one fin was all we found.

We retired from rocketry, as we realized we did not have access to a truly safe launch site. This launch had been at a park playing field, early morning, week day, and no one within hundreds of yards. If a park ranger had heard the explosion, we would have had a tough day. Our previous launches were from a large farm field, no houses with in a quarter mile. That location had no suitable shelter, so launches were electric, from a hundred yards, prone position.

The students had an excellent launch site, well out in the desert, if we had such a location, we might continued. But we would have been in one of the buildings present at the launch site.

The available chemistry for armature use was very limited back then. Several of our earlies rockets blew up following launch, but as the were based on various thickness cardboard tube, fragments were not a danger. The change to a metal tube introduced the need for protection.
 
Sac Arrow said:
Back in another board, a question was raised - how practical was it to launch a small object into outer space via amateur rocketry? (Answer, not very - theoretically possible but it's still going to cost about as much as a SpaceX.)

Here is another example. This one actually did get past the Karman line.

In the original link I posted, we are looking at a very well engineered amateur rocket project with a budget that was likely in the tens of thousands of dollars. The above rocket represents a well funded project hosted by a major university that probably had a budget of well in to the hundreds of thousands of dollars. Maybe even over $1M if you look at all the machinery involved. It's significantly larger, more expensive, and it really didn't go that much higher.

I would say the engineering of the first example was probably better. Towards the very end of the second video, when they recovered the booster, I had a hard time telling but it looks like they may of had a partial in-flight delam of the carbon fiber fins, which probably cost them a significant penalty in altitude.
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The rocket equation figures it out:
https://www.grc.nasa.gov/www/k-12/rocket/rktpow.html

Getting to orbit is hard.

>>>
From the ideal rocket equation, 90% of the weight of a rocket going to orbit is propellant weight. The remaining 10% of the weight includes structure, engines, and payload. So given the current state-of-the-art, the payload accounts for only about 1% of the weight of an ideal rocket at launch. Rockets are terribly inefficient and expensive.
<<<
 
Cool video. "go pro overheats".. Lol, they need to get a Dji camera, go pros suck.
 
As an outgrowth of our homemade fireworks, my brother and I built a few large scale rockets. We started with the motors and basically added fins and a nosecone; no guidance systems.

Luckily, there was a quarry hidden in the hills not far from our house, so we had a place to launch these airborne bombs. We learned quickly that our mystery fuel solid rocket motors were much more powerful than expected. No surprise there, since we applied no kind of physics or engineering concepts into these things.

We also learned that making bigger motors to overcome excessively heavy rockets (due to their crude construction from mailing tubes and thick cardboard tubes used for plastic sheet rolls) will only work until those physics and engineering numbers turn said "rocket" into a pipe bomb. We lost most of them, either from disappearing into the horizon or detonating on the launch platform.

It was fun while it lasted and we were not seriously injured in the process. I wonder just how high those things went...
 
There was a major league pitcher back in the early 1900s called “Three Finger” Brown, so there are options after rocketry.
 
IK04 said:
As an outgrowth of our homemade fireworks, my brother and I built a few large scale rockets. We started with the motors and basically added fins and a nosecone; no guidance systems.
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I don't know if 'no guidance' is still the unwritten rule, but when I was more into high-power rocketry some years ago, the hobby community self-policed that with vigor. Once amateur rockets started getting that big and that powerful, it was assumed that the feds would shut down the hobby in a heartbeat if anyone started experimenting with guidance systems. More effort was put into sophisticated tracking instead, so we could find the dang things after launch.

I still remember a launch quite a few years ago (before onboard GPS was available to transmit the landing location) when a guy who was very much into both the rocketry and the amateur radio hobbies showed up. He had a high-altitude rocket that I recall he planned to launch to 2 miles AGL, and he also had a homebuilt radio direction finder in a backpack, with a belt mounted control module, and a directional antenna about as tall as he was. Also map, compass, water, snacks, etc...he was prepared to walk down his rocket, wherever it might land.

He held up the countdown briefly while fiddling with all the radio gear he was wearing and carrying, then his rocket roared off the pad and was lost to sight in a second or two. There was a much longer delay while it was presumed to be coasting to apogee, but eventually the sound of the separation charge firing was heard (separates the rocket into boost and recovery sections, tethered together by a long piece of tubular webbing). After separation, the rocket can't streamline in, but rather falls much more slowly until the recovery charge fires and the parachute deploys, typically at about 500 to 1000 feet. That greatly minimized drift under parachute.

We heard and saw the recovery charge fire, because as luck would have it, the rocket was just about directly over the launch pad. Once under chute, the rocket proceed to drift to a touchdown about 20 yards directly in front of the guy. He was crestfallen...literally hung his head and didn't move for a bit, before powering down and removing all of the radio gear, and walking a few steps to get his rocket.
 
All my Estes adventures ended one of three ways: Never seen again, seen again but in the top of a tree, seen again but in many small pieces. All my rockets eventually ended up in one of those scenarios.
 
When I was little, Centuri rockets were the shizz. Estes was around, but Centuri made the big cool stuff. I guess they went out of business in the 80's though.
 
Estes and Centuri merged in 1969 and kept both brand names, but the combined company was Centuri Engineering. Eventually the Centuri brand was dropped in 1983, but Estes still exists today under new ownership.
 
I might even have an old Estes down in the basement. One that didn't end up in pieces.
 
I had a number of Estes rockets. I remember one that used spin recovery. There were rubber band loaded spin tabs on the fins/wings that were held in place by the engine body. At or near apogee, the engine would eject and the tabs would snap into position, and the shop would descend with a pretty rapid spin rate that slowed it down considerably. Cool looking rocket, cool recovery mode. It got launched often.

Well… Ambroid wood model cement only lasts so long, I guess. One Spring I put that puppy on the launch rod for the first time. When the engine lit, it started shedding fin parts about as soon as it got to the top of the launcher. It went up with a trail of fluttery bits in its wake. Impressive and fun to watch right up until the end.

Growing up as I did in the land of corn and soybean fields, we did lose the occasional rocket and even an R/C airplane or two.
 
Sac Arrow said:
When I was little, Centuri rockets were the shizz. Estes was around, but Centuri made the big cool stuff. I guess they went out of business in the 80's though.
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I did model rockets in 67 - 68. I was a Centuri guy. My next door neighbor close friend was an Estes guy.

When my family moved, I dropped the rockets, but kept the model airplanes.
 
DaleB said:
I had a number of Estes rockets. I remember one that used spin recovery. There were rubber band loaded spin tabs on the fins/wings that were held in place by the engine body. At or near apogee, the engine would eject and the tabs would snap into position, and the shop would descend with a pretty rapid spin rate that slowed it down considerably. Cool looking rocket, cool recovery mode. It got launched often.
Click to expand...

I had that same rocket! Only it was under Centuri brand I think.

I was big on spray painting my rockets for visibility. I would use model airplane dope as a filler for the balsa fins, then spray paint them either white, or day glow orange.
 
I was just looking at the Estes catalog. So many are snap together plastic and decals.

As a kid, those rockets were my introduction to x-acto knives, balsa woodworking, spray paint (and the importance of using newspapers on the garage floor to prevent being yelled at), different wood glues, and all sorts of reasons to ride the bike to the local hobby shop and spend my allowance and lawn mower money.
 
Estes rockets led me to dope...


...airplane dope, that is.
 
Sac Arrow said:
I had that same rocket! Only it was under Centuri brand I think.

I was big on spray painting my rockets for visibility. I would use model airplane dope as a filler for the balsa fins, then spray paint them either white, or day glow orange.
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Ah-hah! Gyroc, that was the name. https://www.rocketryforum.com/threads/estes-astron-gyroc-k-24-or-1224-gallery.19885/

Plenty of mine got International Orange paint for ease of finding them. Same with the airplanes. All the fins and nose cones got sanding sealer and either dips or spray paint.

I do miss Ambroid. Sort of.
 
I probably built 25 Estes rockets as a kid. Anything from the 1/4 A motor stuff to D motor stuff. Multi stage, boost gliders, featherweight recovery, everything under the sun.

My favorite was (IIRC) the SST, which was a delta wing SST boost glider. I flew it once (only once, ever). It launched beautifully, the separation of the motor tube and ballast weights was perfect, and the glider flew a beautiful 3/4 loop from its vertical orientation to gliding in circles. Out over the nearby forest, which claimed it. Me and my buddies looked for it for a long, long time and were certain of the general area where it had to come down, but it must have been way up in a tree somewhere. I can still picture that magnificent 3/4 loop...
 
I don't know anybody who successfully launched a Gyroc ("successfully" meaning the wings not ripping off).

Later on we got tired of making fancy rockets just to lose them so we just hot glued fins directly to the engine.
 
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