Thanks! Great info. Very helpful to have some solid ranges for the cg as I design my first F1M.
James Alderson
To: Indoor_Construction_at_yahoogroups.com
From: wdgowen_at_gmail.com
Date: Mon, 22 Apr 2013 22:12:37 -0400
Subject: Re: [Indoor_Construction] Re: F1M Design
An F1M will fly (and fly well) with a wide range
of CG locations. My 2009 model had the CG (w/motor) at about 3/4"
in front of the TE. My current one has the CG (w/motor) at
about 1 1/2" behind the TE. Both have been extremely stable. I made
9 flights in a Cat 1 site last Saturday with launch torques up to
1.08 in-oz and had no stability problems on any of the flights.
On 4/21/2013 5:50 PM, aldershine wrote:
I'm catching on that getting the CG rearward enough is
important with F1M. I may plan to go with a built-up prop
to help reduce nose weight and I guess I can plan on a
rather large stab.
To assist with design planning I guess my next step is to
calculate moment weights for the models various components
so that I will not have to put a stinger behind the tail
to get the CG right.
I suppose I can just multiply distances in mm by weight in
grams to determine what my component weights need to be?
Any thoughts?
James Alderson
--- In Indoor_Construction_at_yahoogroups.com,
"Leo Pilachowski" <leop_at_...> wrote:
>
> Let me say that Bill's wing spars using 0.010" carbon
rod on the top and bottom of 0.040" square balsa are about
50% stiffer than using 0.004" boron on the top and bottom
of 0.062" x 0.040" balsa. Increasing the spar height to
0.070" for the boroned spar gives about the same stiffness
for both. This boroned spar will weigh about 70% of Bill's
spar but this amounts to only 90mg difference for two
spars (using 5# wood). Bill's spars may a bit more durable
than boroned spars as boron fibers can pop off. So, you
should use whatever you are comfortable with.
>
> LP
>
> --- In Indoor_Construction_at_yahoogroups.com,
James Alderson <aldershine_at_> wrote:
> >
> > Thanks. Sounds like a good way to get by with my
current supply of wood.
> >
> > Good luck in all your flying. May all the
bounces go your way.
> >
> > James Alderson
> >
> > To: Indoor_Construction_at_yahoogroups.com
> > From: leop_at_
> > Date: Sun, 21 Apr 2013 02:38:57 +0000
> > Subject: [Indoor_Construction] Re: F1M Design
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
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> >
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> >
> >
> > I am not an F1M builder but I have found that if
one uses boron fibers on the top and bottom of the wing
spars, average, but light, balsa can be used effectively
to make stiff wings on similar planes.
> >
> >
> >
> > Leo P
> >
> >
> >
> > --- In Indoor_Construction_at_yahoogroups.com,
William Gowen <wdgowen_at_> wrote:
> >
> > >
> >
> > > My model is 32.5" OA. I think 30" would be
fine. I've used .030" carbon
> >
> > > tubes for wing spars and had pretty good
luck with them. My current
> >
> > > model uses balsa spars about 040" x 040"
with a .010" carbon rod glued
> >
> > > to the balsa top and bottom. These are
stiffer and lighter than the
> >
> > > carbon tubes.
> >
> > >
> >
> > > Aki (3 world records) and Larry Coslick (2
AMA National records) use
> >
> > > built-up props and do well with them. I use
sheet balsa blades.
> >
> > >
> >
> > > On 4/20/2013 6:18 PM, James Alderson wrote:
> >
> > > >
> >
> > > > Thanks for your quick response! I am
rather new to duration events.
> >
> > > > Actually, I'd like to keep the length
shorter so I can allow more
> >
> > > > weight for the flying surfaces. I do
not have the best wood to work
> >
> > > > with so getting sufficient wing spars
to weight is challenging for
> >
> > > > me. I did that with my recent F1L and
it seemed to work out okay.
> >
> > > >
> >
> > > > I will go with a fixed prop for
starters. What about a built-up prop
> >
> > > > rather than sheet blades to reduce
nose weight?
> >
> > > >
> >
> > > > Thanks,
> >
> > > >
> >
> > > > James
> >
> > > >
> >
> > > >
----------------------------------------------------------
> >
> > > > To: Indoor_Construction_at_yahoogroups.com
> >
> > > > From: grrd_moore_at_
> >
> > > > Date: Sat, 20 Apr 2013 21:18:13 +0100
> >
> > > > Subject: Re: [Indoor_Construction] F1M
Design
> >
> > > >
> >
> > > > I'm guessing that the length
restriction is for practical
> >
> > > > transportation reasons? There is no
limit other than span and weight
> >
> > > > for F1m.
> >
> > > > Also I guess you will be using a vp
prop?
> >
> > > > You can easily build the model
underweight and ballast the tailboom to
> >
> > > > get the cg in the right place then
ballast on the cg if necessary to
> >
> > > > get the model weight correct.
> >
> > > > You could also make the model longer
by using an additional tail
> >
> > > > stinger to the end to the end of the
tailboom. This would require less
> >
> > > > ballast and allow more strength to be
built into the structure.
> >
> > > >
> >
> > > >
> >
> > > > --- On *Sat, 20/4/13, aldershine
/<aldershine_at_>/* wrote:
> >
> > > >
> >
> > > >
> >
> > > > From: aldershine <aldershine_at_>
> >
> > > > Subject: [Indoor_Construction] F1M
Design
> >
> > > > To: Indoor_Construction_at_yahoogroups.com
> >
> > > > Date: Saturday, 20 April, 2013, 16:51
> >
> > > >
> >
> > > > I just read the thread of posts for
F1M on Hip Pocket. Our club
> >
> > > > will be adding that event for next
indoor season at our Cat II
> >
> > > > site in Albany, OR. We plan to fly 1/4
motors, no touch.
> >
> > > >
> >
> > > > Is there a way to keep the overall
fuselage length under 30" and
> >
> > > > keep the CG rearward enough? For my
first model I am thinking of a
> >
> > > > traditional design with dihedral, no
tip plates and single fin.
> >
> > > >
> >
> > > > Thanks,
> >
> > > >
> >
> > > > James Alderson
> >
> > > > Willamette Modeler's Club
> >
> > > >
> >
> > > >
> >
> > > >
> >
> > >
> >
>
Received on Mon Apr 22 2013 - 21:16:38 CEST