Re: F1D CG poll

From: Mark <f1diddler_at_yahoo.com>
Date: Fri, 14 Dec 2007 15:53:16 -0000

--- In Indoor_Construction_at_yahoogroups.com, Tapio Linkosalo
<tapio.linkosalo_at_...> wrote:
.
>
> But now, are there no comments on the CG location? Is this
classified
> information?
> -tapio-
>


No, not "classified info" in a selfish sense, but perhaps combination
of other factors. 1. There are few F1d flyers to start with. 2. We
may not be so confident about *our* current CG set up, unless we won
the last big contest we attended! 3. Our not having anything better
to say than recent comments of Mr. Bailey, brief but good, IMO. 4.
The Limbo stick effect--how low can you go? AS tail volume
increases, seems you can go further and further back, sometimes with
impunity, in good conditions. Maybe no one wants to suggest "the
limit" as it may be personal style of how much instability to
tolerate, in hoping for a perfect flight in perfect condition.. 5.
Wariness of suggesting anything "advanced" to someone building F1ds
to 1.75 g or some such unecessary weight, which suggests more
important problems than CG, (perhaps which also affects "best" CG for
your case.) I believe you reported B Hunt's suggestion of 75% for
the Big Square, but I also recall something like "move back to 85%
with experience" or something like that.

But a poll is a poll, and fairly asked. I bump around from 85% to
90%, but don't measure it often. It's not easy to change CG on F1d
unless you're underweight and can mess with CG using ballast,
meaning, some of us merely build to a preferred nose-to-wingpost
length to clear steering line by a certain amount, and that pretty
much sets CG. If I don't like the apprearance of how in flies (sink,
or instability) then I'll think about messing with wing position.
But usually "it is what it is." I may try a flight with ballast on
tail post, then one with ballast on nose, but usually that experiment
is inconclusive on any of my good models. With proper component
weights, CG should come out pretty close to "good."
Mark F1diddler
Received on Fri Dec 14 2007 - 07:53:19 CET

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