Saturday, June 22, 2013

The largest rocket I'll ever build

Non-operational, unfortunately.

The body tube is a 6 foot length of 30" diameter concrete column form from a construction supply place (Whitecap). The fins are two layers of corrugated cardboard, laminated with corrugation in perpendicular directions, lined and attached with black duct tape. The nose cone has a frame built of 2-by-2's, then is made with cardboard and covered in a mylar. It was painted with Rustoleum indoor/outdoor latex using a roller. It is kept from tipping by lashings to the playset behind with long, thick zip-ties.

Perhaps the most impressive part is that I had only three days to acquire parts, assemble, and paint it. So most of the work was done late at night, in unusually high winds. No time to smooth out body tube spirals on this beast.

The very top was meant to look like the escape tower of the Saturn V, but most of it was broken off by a rambunctious young guest at the birthday party the day before. Given more time, my idea was to make this part into an actual rocket that could launch off of the top, just as the actual escape tower was meant to do. Alas, the whole thing has found a permanent position elsewhere in our yard, under a big tree, so that won't happen.

As always, I learned something about materials and techniques during the build. My big lesson on this one? Duck brand tape is far superior to the Scotch brand duct tape.

Tuesday, June 11, 2013

How High?

I'm horrible at judging distances. I like to blame this on the fact that I've got great vision in one eye, and am very nearsighted in the other, effectively leaving my brain with no parallax to work with. After a rocket lands, I'm the guy searching for it in bushes twice as far from the pad as it actually landed.

I figure that I'm probably the same way about height, but I have another excuse there. I've run 1000 feet, or 2000 or 3000, but I've never jumped that high. But on a recent vacation to Arizona, it occurred to me that it might be interesting to compare the heights of some familiar things to the heights of some familiar model rockets. So here we go:

   14 ft - Robert Goddard's first liquid fuel rocket
  154 ft - Space Shuttle external tank
  305 ft - Statue of Liberty
  363 ft - Saturn V rocket
  455 ft - Great Pyramid at Giza
  500 ft - Estes Big Bertha (C6-5)
  564 ft - Highest baseball pop fly (Ted Williams, 1941)
  570 ft - Depth of Meteor Crater in Flagstaff, AZ
  630 ft - St. Louis Arch
  698 ft - Denver "Cash Register" building
  900 ft - Estes Mean Machine max height (E9-6)
 1100 ft - Estes Alpha III max height (C6-7)
 1454 ft - Empire State Building
 1463 ft - Eiffel Tower
 1600 ft - Estes Mongoose (C6-0 + C6-7)
 1771 ft - My personal height record - Estes Magician (E9-6)
 2722 ft - Burj Khalifa (Dubai)
 2887 ft - NAR altitude record for a D engine flight
 4030 dt - Snowmass ski resort "True-Up Vertical Descent"
 6000 ft - Grand Canyon (depth)
 8664 ft - NAR altitude record for a G engine flight
14,509 ft - Kite AGL record
20,000 ft - NCR standing FAA waiver ACL height
6 miles - Homer Hickam's final BCMA launch, June 1960 - Auk XXX1

There you have it. Your "typical" BP model rocket will go around as high a big skyscraper, but you need a G engine and a good design to fly out of the Grand Canyon.

As a rocketeer, I find the NAR records and Homer Hickam's launches (detailed in the very readable Rocket Boys) pretty darn impressive.

Looking for record heights on more advanced amateur rockets becomes a pretty divergent (but interesting) task because you start to consider clusters, multiple stages, and even experimental rockets. So I didn't include anything from that realm. The amateur record height is 72 miles - technically in outer space - so we'll just leave it at that.