Single Shot Sweepstakes 2006

[denverdoc]

Not sure were ever going to get 26k or whatever it was back, but like NCR we have a plan. The large majority of active members are L3 and EXmen, we’ve got some great dev’t work going on between Brad and John B in terms of solids, and Ed W is fine tuning his instant-on and thoroughly outrageous M hybrids. The statics on these have been absolutely hair raising. The meetings are very informative (held in Englewood) and the mixing parties a lot of fun–if you want to see how EX its done, or just cop a small motor, come on out (arvada)!

And a great group besides. The club is definitely rising up from the ashes and I expect will be sponsoring some very ambitious projects in the coming years.

JS

[Anonymous]

Warren wrote:on the other hand, that 3000′ of additional altitude at the launch site definitely added at least 500′ and maybe as much as 800′ to his altitude, despite the cold temperature, maybe even more.

I got curious about the “Hartsel effect” and did some sims using my G record rocket regarding Hartsel vs. the N. site. I was quite surprised by what I found. I simmed for Hartsel, at 49 degrees (actual temp when I launched) vs. the N. site and 85 degrees. Last Saturday, I had to fly before it warmed up, as the window was open and I felt like it was getting windier by the minute. At any rate, the difference between those two sims? A paltry 51′.

Taking that one step further, comparing that with a 4400′, 95 degree, 20% humidity site — typical of, say, a Las Vegas area lakebed… the Hartsel site offered a 101′ advantage….

[Bruce R. Schaefer]

I agree, John. From my limited experience, altitude DOES have an effect, but it is limited and not what one would think.

My altitude in Illinois was consistently 212 feet. In Colorado Springs 213 feet.

[Warren B. MusselmanModerator]

Keep in mind the issue isn’t altitude, but air density.

Warren

[Anonymous]

Keep in mind the issue isn’t altitude, but air density.

Warren

Very correct. 70 Deg F @ Hartsel, and you have something. I bring all this up because your earlier post suggested a 500-800′ advantage in recorded altitude… Perhaps on a PERFECT day in Hartsel vs. a marginal day down here, but certainly not the case last week.

What was a real bummer is that right after I flew, the winds died and it warmed up nicely. Had I waited, I’d have been far better off. It is always a crapshoot….

[Bruce R. Schaefer]

Keep in mind the issue isn’t altitude, but air density.

Absolutely. My apologies. Environmental conditions determine how high she’ll fly, given optimum weight, finish, design, etc. Put it this way, same rocket flown in different air densities (humidity, temperature, etc. factors varying) will achieve different altitudes. Correcto mundo. Du hast recht. Yep.

[Bruce R. Schaefer]

Best laid plans… got my rocket to an acceptable finish in case the conditions are right tomorrow (by the way, I always carry a temp and relative humidity meter with me, in case someone needs to know those conditions), just one tiny paint zit left, had lots of bubbling this time, because I experimented with different coverings, almost to my ideal weight–about an ounce (or so) light, gonna have to do something about that… anyway, loaded in the MAWD, tested the electronics, a-ok, stuffed the 10′ 1/4″ Kevlar harness in, along with the empty ejection can, then the parachute… (grunt) then the parachute… I’ll be… I didn’t leave enough room… the basics, right? 🙄 Even old NAR guys screw up… but there are always work-arounds, alternatives are to add a 4″ body tube section, no problem, have the coupler and tube, maybe I shouldn’t have gone min diameter… oh, well… have to paint THAT now… or, buy some elastic… hate elastic, breaks–only has to work once though–but it can slam things together; however, it can be crammed in… I can cut the harness down and use Kevlar thread, have that, even though it’s rated to take the stress, it’s so thin and more likely to tangle… hmmm… this is what happens when you get in a hurry… you end up have to make more trade-offs than you intended… one thing I did rediscover though… WAX and RUBBING/POLISHING COMPOUND… haven’t used it since the late 60’s. I’d forgotten how effective it is in getting a really smooth finish. I really think I’ll wax all my rockets from now on. Okay, there’s always good coming out of a challenging experience. All this has really brought back some good, old memories. I’m in this contest just to have fun and compete–at this point, mostly against myself. 😀

[Author]

Posts