Re: my analysis: Kibbie Dome times vs. Johnson City
A couple of weeks ago, I found the density of the air at Johnson City and Moscow. Johnson City came out at 90.94% while Moscow was 92.31%--a mere 1.37% difference. I took the data required from the national weather service's website.
So, the air density doesn't account for the differences in times given the two very different heights. At Lakehurst however, I talked to Larry Coslick who said that the temperature difference in Moscow between the ceiling and floor was about .2 degrees. This is quite odd seeing that the difference at Lakehurst is about 10 degrees. Anyone who walks to the top of the bleachers at Johnson City can notice a difference in the temperature; thus, there must be some sort of difference between the floor and ceiling--at least .2 degrees. I think that the Kibbie Dome is heated in some way to give an even temperature and that this is the reason for the comparable times even with the higher ceiling.
Brett
----- Original Message -----
From: Mark
To: Indoor_Construction_at_yahoogroups.com
Sent: Monday, July 17, 2006 4:59 PM
Subject: [Indoor_Construction] my analysis: Kibbie Dome times vs. Johnson City
11 duration rubber events had higher winning times at JC than at
KD. One duration rubber event (F1L) had higher KD winning time than
JC. UCLG and SCLG had slightly higher KD times.
The 11 rubber duration events with higher JC times had the following
% higher times, averaging out to 9% higher across these 11 events.
Intermediate Stick (12%)
35cm (10%)
Bostonian (27%)
F1D (5.5%)
AROG (4%)
WS (7.6%)
Ministick (2.1%)
EZB (4.8%)
OPP (4.6%)
A6 (28%)
LPP (3.3%)
The question, of course, is attribution. How much of the above is
attributable to better flyERS or better models versus better site
and/or conditions? In many cases (A6, Bostonian) some difference is
obviously due to a modeler who specializes or excels in the event vs
a flyers at KD who does not. IOW, more high level competition at JC
in a some events. In other cases, a few winning KD times probably
could have been higher had some multiple-event flyers needed to do
so. For example, in ministick, I landed with maybe 500(?) turns left
out of 4000. I could have shortened motor for another try, but the
first flight held on for first place, so I didn't bother with a
second flight. Similarly, in OPP, my second flight held on for
first, but I didn't get too near ceiling, and didn't bother to try
improve it.
JC elevation is listed per Google as 1635 ft, and Moscow 2560 ft.
That's less than 1000 ft difference. Is altitude-density so
different within 1000 ft--enough to account for 9% difference? I
think temperature dispersion may explain more. KD contains so many
more cubic ft. that thermals and warmer layers disperse before
providing much benefit for very long. Of course, that's given an
indoor space which doesn't interact so much with outdoor weather, as
opposed to say, Lakehurst Hangar 1.
Also, I think the bottom-beam height at JC is more easily pegged than
at KD due to ease of visibility and judgement about just where the
model is. Consider how often we hear "I only reached the curtain"
at KD. (Often) Or how 'bout, "I got close to ceiling tiles,
but..." (Often). This could very easily mean 10 or 15 ft below the
tiles at KD, since it's hard to judge just how close you are unless
you walk to other end of building, and view from different angle.
Besides, at KD, a flight all the way to the top is much more likely
to be something risky (thanks to curtain wires) than a similar just-
to-beams flight at JC. This discourages risk taking, except by the
risk takers!
Take away the thermal gifts either site can offer, and I suppose
there would be about a minute difference between a good F1d flight at
JC vs. KD. That's only 3% difference.
We really should remember to now n then send a thermometer up to
ceiling with a balloon at both sites.
I'll be glad to do so at Kibbie 2007! (Provided we still have modern
civilization intact come July 2007.)
Mark Bennett
[Non-text portions of this message have been removed]
Received on Mon Jul 17 2006 - 14:47:41 CEST
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