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
> <mailto:Indoor_Construction%40yahoogroups.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
> <mailto:Indoor_Construction%40yahoogroups.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
> <mailto:Indoor_Construction%40yahoogroups.com>
> > > From: leop_at_
> > > Date: Sun, 21 Apr 2013 02:38:57 +0000
> > > Subject: [Indoor_Construction] Re: F1M Design
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > 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
> <mailto:Indoor_Construction%40yahoogroups.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
> <mailto:Indoor_Construction%40yahoogroups.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
> <mailto:Indoor_Construction%40yahoogroups.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 - 19:12:40 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:47 CET