2185Re: [GPSL] The mystery of the near constant ascent speed
- Apr 1, 2006I tried looking at the drag equation and seeing if I could show the
balloon's speed should be constant. But I kept coming up with a speed
that was not constant. I'll see if I can find my notes and show my
>>> manes@... 3/24/2006 9:57:24 pm >>>Hi Hank,
Well, like so much other technology that's been once well-understood
and slowly forgotten (like the MIT Series), I'd be not surprised if
somewhere lurking out there is a paper which precisely describes
latex balloon ascent behavior.
Sounds like a great topic for an aero engineer's master's thesis!
73 de Mike W5VSI
Hank Riley wrote:
>>We were deep in to Reynolds and--
>>Grashof numbers and finally decided that the only way that this
>>phenomenon can be explained is to allow the shape of the balloon
>>to deviate from a sphere over the ascent course.
> I guess that it just has to remain a mystery with a plausible
> but not rock solid explanation if you guys didn't solve it.
> Also my derivation that had the balloon either speeding up
> or slowing down with increasing height (guessing it was the
> former) was okay as far as it went, making the usual
> assumptions. It's just that the basic model is missing
> something, like the variable shape factor you mention.
> It still amazes me that the ascent speed seems to adhere as
> well as it does to a constant. There are a good number of
> anomalous amateur flight logs, but I believe the vast majority
> are really pretty steady from liftoff until burst.
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> Yahoo! Groups Links
Mike Manes manes@... Tel: 303-979-4899
"Things should be made as simple as possible, but not more so." A.
Yahoo! Groups Links
- << Previous post in topic Next post in topic >>