Thanks for sharing that dik,
I remember my Estes model days, too.

It was a little 'dry' but extremely well done. I wish I had have known that 60 years back... used to mix 2 to 1 by volume. I didn't do Estes... Aluminum alloy tube, oak nose cones turned down by my uncle and nozzles made by a neighbour, from fired clay. My first one was a real disappointment... front ignition using my electric train transformer, and pffft... it was gone in the 'blink of an eye'. I was expecting it to lift off like the rockets on TV.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

We built model rockets in 8th grade science class and shot them off from the football field. Students were stationed around the school grounds to retrieve as many rockets as we could find, although several ended up on the school roof.

Later on, I was in college and my younger brother wanted to build a rocket for a 4-H project. We built a couple from Estes kits and launched them from a semi-hidden spot at the extreme back of a county park. Retrieved the rockets and launched again. My brother kept his for display, but I didn't mind sacrificing mine for an "experiment". For the third launch I loaded up an engine that was far more powerful than was recommended for my rocket. We fired it off and it completely disappeared into the sky. We never saw either the parachute or the free-falling rocket body.

Leaving the park, we passed a ranger driving in a hurry in the opposite direction. We chose to get out of Dodge promptly.

Quote (We fired it off and it completely disappeared into the sky. We never saw either the parachute or the free-falling rocket body.)

That's what happened to my first one... was little shy of 4' long and 1-1/2"dia with 2' of 'rocket motor'; it was gone in the blink of an eye and never recovered. Oak nose cone and no parachute. When I touched it off... I was a bit of a kid, working on my own, and had no idea if it would work or if it would detonate.

I never used a parachute... thought about it using a battery, mercury switch and small explosive charge to free the nose cone, but never tried it.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Very cool. I started with Estes kits as a kid and then built everything but the engine from scratch for a bit. I'm not sure why I didn't think to try building those too.

Now I'm eying those speakers he built in another video...

I don't know what kids would do today... back then, I called the cops to see where I could set it off... they told me to check with the airport. The airport told me I couldn't...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Used to build hundreds of the Estes powered ones, but that was how it was in Houston in the 60s. We
were all in the race to space back then. I got my pilot's licence 3 weeks after I got my driver's license. Would have been the other way around, except the weather was horrible that month and couldn't get any VFR conditions to take the flight exam.

Had this poster taped to my bedroom wall.



All you see these days is some rapper's face surrounded by tattooed ladies.

A black swan to a turkey is a white swan to the butcher.

My first rocket experience was in the playground of a nearby elementary school. I was probably 10 years old and a family was launching their rocket and I was interested so they offered to let me assemble the rocket and push the button. It was amazing, I had never experienced anything so thrilling. But the wad caught fire and melted the parachute. The rocket was coming down fast and the dad tried to catch it. It hit him in the face. They were immediately unhappy with me so I decided it was best to leave. The event did spark an interest. I built a few badly painted rockets that are probably still sitting on rooftops today.

I was about 10 or 12 when I build my first rocket... I was in grade school, Gd 5 or 6... but had access to all sorts of stuff and uncles with all sorts of equipment. We were 'dirt poor', but had 'stuff'. My one uncle had a heating business and my grandfather was a tinsmith.

At that age, I helped by dad solder eavestroughing on weekends. He worked with CP Express, but did part time work installing eavestrough... it was soldered together back then, not rolled. I often cut and soldered mitres for corners. It was a propane tank and pot with copper irons, back then. My birth certificate lists my dad's occupation as a 'tinsmith', and often used my dad's table saw... got my first 22 about the same time... just different times, and brings back fond memories.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Yes, I got my first 22 when I was nine years old. I still have it, locked away in my gun safe.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

Neat...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

"just different times"
My brother and I used to travel alone on the SantaFe RR Chief between Houston and Chicago in the 50s. We were 6 and 8yrs old and it was a 2-day trip. You probably have to carry an assault rifle to do it today, but heck, even 9yr olds have them.

A black swan to a turkey is a white swan to the butcher.

A bad sign of the times... I still feel safe... back then it was never a concern.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

I used to do Estes rockets also. I used to take my kids to Mile Square Park and let them catch them as they parachute down. Bummer that park turned into another gold course.

ctopher, CSWP
SolidWorks '19
ctophers home
SolidWorks Legion

Yes, I had friends who used to go to Mile Square Park when the 'runways' were still there to fly model airplanes.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

I never got into rockets. I did help some friends build motors for theirs.
For a while I was into kites, double boxes and tetragonal ones.
Used to use 80# and 100# Trilene as kite string. Nice 500yd spools so you only needed a couple of them.
Flew them in central IN where it is flat and you see for miles.
Even played with running cameras up the line for arial photos.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

When I grew older (didn't grow up, yet) each spring I used to build box kites for the kids... we'd put them up several hundred yards with braided nylon string... Lift was such that often the kids couldn't handle it. When we were kids, we used to make kites and have kite 'fights'.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Rocket science

A black swan to a turkey is a white swan to the butcher.

• https://files.engineering.com/getfile.aspx?folder=21bd8480-f72f-4938-8485-2

And

A black swan to a turkey is a white swan to the butcher.

• https://files.engineering.com/getfile.aspx?folder=aedbc83c-7709-4e31-a312-9

Thanks for the link...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Now with some dreamed up model data and these Estes rocket engine performance charts,
Thrust vs time chart links for each model, click the little picture upper left,
Some ambitious soul could probably write a Python or Excel-VBA flight simulator.

https://estesrockets.com/product-category/engines/
Or these
https://www.thrustcurve.org

Of course there are some already written
https://duckduckgo.com/?q=model+rocket+flight+simu...

A black swan to a turkey is a white swan to the butcher.

Thanks 1503...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Happy contrails.

A black swan to a turkey is a white swan to the butcher.

I have a question about missils, I guess you can define them as a rocket.
There are a lot of photos of missils sent of from Russia or Russian occupied land.
In many of them it looks like this.





It doesn't look like they have a very good guidance or what you might call it, going a bit here and there, how precise can a missil like that be?
When it looks like, it can't fly straight?

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

Depends on the type. Some guided missiles will follow a target. The contrails you see can also be blowing around from winds.

ctopher, CSWP
SolidWorks '19
ctophers home
SolidWorks Legion

Even orbital rockets/missiles are often seen leaving odd-looking contrails.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

Hmm okey just something a reflected over..

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

Wind speeds change drastically at certain altitudes

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

It probably looked a lot straighter five minutes previously.

I think it may have some to do with exhaust temperature, velocity and generstion of trailing vorticies, as it accelerates. Seems to be some axial rotational, corkscrew trail, more pronounced towards the higher the altitudes, until about 80% -90% length, as we'll as wind shears. But really just a guess. I think wind over flat terrain generally increases Velocity@10m_Height * Height^(1/7). Doubling the height increases velocity by 10%.

Anything useful here?
https://elib.dlr.de/83242/1/ATILA.pdf
https://duckduckgo.com/?q=rocket+exhaust+cfd&t...

A black swan to a turkey is a white swan to the butcher ... and to Boeing.