Blasting into the unknown...
March 10, 2014 6:10 PM   Subscribe

DIY model rocket builders do it (YT) Just searching for cool things (COOL!) people do that I'd like to try.... Prev on the Blue... Steve Eves launched a 1:10 scale Saturn V.
Of course you can get just a lil creepy with this sort of thing.
then a 12 year old already.

Makes me feel like a 12 yr old... sheesh
posted by shockingbluamp (21 comments total) 10 users marked this as a favorite
What prevents that gigantic thing from just being called a "rocket"?
posted by rikschell at 6:25 PM on March 10, 2014

I had an Estes Saturn V like in the last link. It flew nice on a D engine (I never trusted my ability to cluster 3 C engines). I flew it 4 or 5 times. Most all of my rocket stuff got thrown out in the great move of '95. I still have a little bit of an urge to build and fly something, maybe go to a NARAM. The big rockets people build these days are awesome, but also feel wrong to me.
posted by DarkForest at 6:26 PM on March 10, 2014

What prevents that gigantic thing from just being called a "rocket"?

Looked about the size of a V2 to me.
posted by Meatbomb at 6:35 PM on March 10, 2014

Does it actually make it to space? I don't think so, it is pulled back to earth; but someone with more knowledge would know, right?

My husband and I have been arguing over whether or not it would be possible for amateurs to launch things into space. I have a dream of someday being able to launch thousands of tiny probes at objects in space... I think I even have an old ask me about it. But things are just getting lighter and the hack/maker community capable of more sophisticated builds, I keep thinking it's got to be possible.

I understand the issue with fuel and weight, but what about a balloon assisted launch?

Anyway, if this was actually space and not just really far outer atmosphere, then we're closer than I thought.
posted by [insert clever name here] at 7:02 PM on March 10, 2014 [1 favorite]

Homemade rockets get way creepier than that.
posted by The 10th Regiment of Foot at 7:34 PM on March 10, 2014

What prevents that gigantic thing from just being called a "rocket"?

IIRC, model rockets can't have any guidance or steering systems.

Does it actually make it to space? I don't think so, it is pulled back to earth

You can go into space without attaining orbital velocity. Space is just altitude.
posted by ROU_Xenophobe at 7:51 PM on March 10, 2014 [1 favorite]

One problem with amateurs launching things into space is that the technology to put a five pound probe on an accurate trajectory to Mars is pretty much exactly the same technology you need to put 50 pounds of high explosive anywhere on Earth. ICBMs don't have to carry nukes.
posted by Hatashran at 8:04 PM on March 10, 2014

First, when going over the video with a friend of mine, he noticed that this video is stolen from this video of an attempt for the Carmack Prize, built and launched by Derek Deville. Here's the project page for the actual rocket. The rocket only actually made it to 121,000 feet, which is about 207,000 feet shy of space.

Anyway, what ROU_Xenophobe said. Going to space is easy, relatively speaking. It's staying up there that's hard. Delta-V is the currency of the realm when it comes to rockets, it dictates how much velocity a given rocket can add in any given direction. A quick back of the envelope shows that getting to 100 km is requires 1400 m/s, plus a few hundred extra meters per second to punch through all that inconvenient air. Getting to 100 km and staying there takes about 9600 m/s. That's the 1400 m/s for altitude, ~1000 m/s for drag, and that leaves us with roughly 7200-7600 m/s, which is right about what further half-assed math says is orbital velocity at 100 km (square root of ((Mass of Earth*Newton's gravitational constant) / (100 km + average radius of the Earth) = 7844 m/s).

So, what if we wanted to get to space? Let's imagine that we rebuild Derek's Qu8k with a super-material that allows us to make the rocket arbitrarily large enough to hold as much propellant as we want with the same rocket mass. Looking over his plans shows that the rocket massed about 75 kg dry, and some more math gives an exhaust velocity of 1888 m/s (Total impulse/propellant mass).

That gives us all we need to fill in the gaps of our friend and enemy, Tsiolkovsky's rocket equation. Algebra and plugging things in gives us a rocket mass of 157.4 kg to reach 100 km, but not stay there. If you want to stay there with our imaginary rocket, you need to take our humble 75 kg rocket and stack 12 metric tons of propellant onto it. That might be a little difficult.
posted by Punkey at 9:49 PM on March 10, 2014 [4 favorites]

When I was in my jr. high school's model rocket club, one guy's dad ponied up for one of those 3.5-ft-tall Saturn V rockets. It was HUMONGOUS compared to the little one-engine deals most of us were bringing. Unfortunately this kid was not the most meticulous of people in either building or in prepping the firing mechanisms. When he launched the monster only two or three of the five engines lit up, so the rocket ponderously rose maybe 20 feet, tilted over on its side, dropped and SA-MASHED onto the asphalt, shattering into a zillion plastic pieces. It was definitely impressive, but not in the way he had hoped.

Is model rocketry still a thing days? Now I'm tempted to get back into it.
posted by Greg_Ace at 9:56 PM on March 10, 2014

"thing days"?? thing these days...
posted by Greg_Ace at 10:23 PM on March 10, 2014

Is model rocketry still a thing days?

Yes. Check out Tripoli Rocketry Association and NAR. TRA is the more advanced stuff. NAR includes the small stuff. They overlap to include "high power" sport rocketry.
posted by neuron at 10:23 PM on March 10, 2014

Even at 1:10 scale, a Saturn V is pretty damn big.
posted by MtDewd at 5:26 AM on March 11, 2014

our friend and enemy, Tsiolkovsky's rocket equation [..] 12 metric tons of propellant

If you're interested in the physics and chemistry of rocket propellants, you should read Ignition! An Informal History of Liquid Rocket Propellants [200 page PDF].

Ignition! discusses the researchers, labs, chemistry, and history of American rocket research in the mid-20th century. You get a good sense of the technical barriers to high performance rockets as you read about the goals and setbacks of the various research projects. Note that this book is a first-person account account of an exciting period of scientific discovery; it's not an engineering textbook.
posted by ryanrs at 6:08 AM on March 11, 2014 [2 favorites]

Yup, I did model rocketry as a kid. And that, my friend, is an Evel Knievel X2 Skycycle made by Centuri. That picture was taken at an abandoned Nike missile base in the Watchung Reservation in Summit, New Jersey.

My dad and me and my brothers did all manner of model rocketry that usually included some spectacular failures, but I loved building them.

Failures included:
1. Not checking that the engine going into the rocket was a booster engine. Said rocket exploded into a ball of flame about 20 feet up
2. The payload rocket carrying a salamander that failed to eject the nose cone (likely it was too tight) and went straight down in to the mud. The salamander was liquified.
3. The Estes Mini Mosquito rocket that completely vanished off the face of the earth.
4. Dad borrowed an expensive Camroc nose cone from a peer at work. He returned it in several pieces with a check.
5. The Estes Flying Model R2D2 Rocket (disclaimer - doesn't so much fly as present a spinning land-based hazard)
6. Countless rockets left hanging in high tree branches.
posted by plinth at 7:30 AM on March 11, 2014

The Estes Mini Mosquito rocket that completely vanished off the face of the earth.

Yeah, as I recall they tended to do that often. One brief "PFT" and they were gone forever. Didn't stop us from getting more, because hey, the sight of that amazingly fast takeoff was worth the price of admission!
posted by Greg_Ace at 10:05 AM on March 11, 2014 [1 favorite]

This is a pretty neat rocket, but yeah the into space claim is specious. I couldn't find an altitude reported in the video. But if as claimed above they reached 121,000 feet, that is not even half way into space. Also far from the real challenge of orbit.

Model rocketry is a lot of fun tho, I'd like to get back into it as my daughter gets older so I can teach her.
posted by MrBobaFett at 10:48 AM on March 11, 2014

Pfft, real men launch anvils.
posted by entropicamericana at 2:05 PM on March 11, 2014

Pfft, real men launch anvils.

They do it for the sound mostly.
posted by The 10th Regiment of Foot at 2:20 PM on March 11, 2014

Listen for it at 3:25 in this video.
posted by The 10th Regiment of Foot at 2:24 PM on March 11, 2014

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