Question about the AukXXXI/Miss Riley rocket

Hi Chuck.

I know nothing other then seeing the movie.

My wild guess just for grins would be a medium J motor.

Way too low. They were aiming for 20-30000' and didn't exactly build them light!

Hi Darren,

They would have had to get an O motor to get to 30k would they not ?

a high ISP N 4" rocket will do about 22K in ideal situations with fiberglass weights.

back then the isp was real low was it not.

what was the rocket/motor diameter of the Miss Riley ?

Anyway, Homer posted on this list a few times in the years past, I wonder if he will again ?

Pretty sure they weren't using fibreglass!

If it was APs ISP it would be say a full L maybe 2% M at 54mm. but they would have been using heavy steal pipe not 6061, the inside would be maybe 38mm

but is that not way over what an AP motor could be in length and not cato at that diameter ?

Pure wild guess they were using cored/end burners back in those days.

Were they were using Zinc/Sulpher propellent ?

It's been a number of years since Homer spoke at my office but I believe he told us that flight was Zinc/Sulfur.

Dave

David Bacque wrote:

Just found this post from Homer Hickam by Googling rec.pyrotechnics:

Homer Hickam Oct 21 2004, 12:48 pm Newsgroups: rec.pyrotechnics From: snipped-for-privacy@hiwaay.net (Homer Hickam) Date: 21 Oct 2004 10:48:36 -0700 Local: Thurs, Oct 21 2004 12:48 pm Subject: Re: Rocket Manual For Amateurs and Zinc/Sulfur Rockets

I was recently apprised of this thread. It's true that the Coalwood Rocket Boys of my memoir Rocket Boys/October Sky preceded Brinley's manual. I wish we'd had it as it would have saved us some work! Principles of Guided Missile Design, an advanced graduate school-level text, was provided by our teacher, Miss Riley, and taught us how to do the calculations necessary for the design of DeLaval nozzles. Propellant, however, was a different story. This was mostly made up as we went along. We progressed from a crude black powder mix (never very successful) to melted potassium nitrate and sugar which we called Rocket Candy. "Candy" was difficult to make and cast but did allow us to reach some significant altitudes. We then progressed to the big Zincoshine Auks (we named our rockets after the Great Auk which couldn't fly - a sense of humor when working in the arena of rocket propulsion is always a good idea). These supersonic rockets utilized zinc dust and sulfur with pure alcohol as a binder which we called Zincoshine (the 200 proof stuff came from a moonshine still). Although we ruined more than one bathroom scale, we finally devised a static test stand and thrust measuring device to provide the numbers necessary to accomplish our designs. Our last rocket went over six miles high. How we did it is all in the original memoir and the follow-on titled The Coalwood Way. The movie, October Sky, based on my memoirs is mostly made up and nearly all the science (and very definitely the propellants shown) is wrong. For more information, check out

Thanks, Homer Hickam

Thanks Rick.

Looks like I need to pick up the book, the movies all wrong ;)

I'll have to read to find out how they tracked it to 6 miles, it's got my interest now unless someone here knows.

in a composite airframe 2.25 rocket a K-250 holds the record at 25K.

Time of flight. The rockets had no recovery device and returned ballistically. By timing the flight from first motion to the sound of impact they could estimate the apogee.

have been using heavy steal pipe not 6061, the inside would be maybe 38mm

that diameter ?

When I did my own guesstimates I used the basic information from the book. A steel pipe rocket about 6 foot long and 2.25 inches in diameter. Since I have a similarly dimensioned rocket I designed, I adjusted the weight in Rocksim, slapped in the largest motor it'd hold (an L) and got about 3 miles in the sim. Since the Rocket Boys were estimating altitude with simple ballistic flight timing I set that as a minimum power required. I figure atmospheric drag likely skewed their calculations and the rocket actually flew lower. Assuming the AukXXXI got near 6 miles I figure the power requirements had to be at least an M, and more likely an N. Which is why I asked, wondering if anyone knew definatively on the subject.

The thread's been an interesting read. Especially since it hasn't degraded into anything but the original and related subjects.

Chuck