Electric Airframes

[J.Oddino]

Chad,
Thanks for the info.  I wish everyone would appreciate what you pioneers are
doing instead of badmouthing the fact that the bad news is not reported.  It
is interesting that the human seems to like bad news as long as it is
happening to someone else and justifies their opinions.

As far as I am concerned it is our rules, that drive us to glow engines,
that has retarded the expansion of pattern competition while IMAC keeps
growing.  Look at this list and see what is the most popular (problematic?)
subject.  Engines, mounts, headers, pipes, pumps, fuel regulators, tanks,
etc., etc. What is the real life cycle cost of a competitive pattern engine
and how many do you need per season?  Anyone got that data?

I'm particularly interested in the lighter feel.  Does that mean light on
the controls or bouncing around light?  I would think the faster flying
plane would be more responsive to the stick and more stable but maybe it has
something to do with the larger slipstream off the electric prop.
You didn't say if the Twister would be electric?  It will be interesting to
see how many folks go back to glow after flying electric.

Jim O

----- Original Message ----- 
From: "Chad Northeast" <chad at f3acanada.org>
To: <discussion at nsrca.org>
Sent: Thursday, September 22, 2005 8:16 PM
Subject: Re: Electric Airframes


> Over the years I have had 3 ZN Enigmas, 2 of them electric (both weighed
> 4670 grams - 10.3 lbs) and 1 glow ( 4600 grams - 10.1 lbs dry).
>
> None were built any different than the others, all used the stock kit
> parts and all were built to take glow in case the electric didnt work
> out and they needed to be switched.  The glow model has survived around
> 1500 flights on it over a number of years, so I suspect the electric
> models would last for 10,000 if given the opportunity!
>
> Now, the electric could be made a bit lighter, mostly in the wings/stab
> as the fuse is already very light and I would be concerned with losing
> rigidty should it be made much lighter (less cloth/resin).  The big
> problem in doing this is that the wingloading is all wrong for the model
> now.  My electric Enigma's feel noticably lighter in the air than the
> glow one and I would not want them any lighter than they are.  I toyed
> with the idea of increasing the weight but decided to just leave them
> alone and get used to it.  In very smooth calm air a light airplane is
> great, but they dont make for good all around models that need to deal
> with turbulence and wind that is usually common!
>
> I will be getting ZN's new Twister as my plane for next year and the
> wings are slightly smaller than the Enigma's so I will shoot for
> somewhere between 10.25-10.5 lbs as a target weight RTF.
>
> Thats my take on it anyways!
>
> Chad
>
> Chuck Hochhalter wrote:
>
> > Alright now, going beyond the motor setup, how about the actual
> > airframe itself.  For certain the weight of the airframe is a huge
> > factor.  Lighter is better esp for electrics as you can run a
> > potentially different battery setup as current, watts etc are
> > decreased (?).
> >
> >
> >
> > Do the stresses on the basic internal structure change enough to allow
> > a plane to be built significantly differently and lighter in areas
> > that were OVER built for the stresses of large vibrating IC motors?
> >
> >
> >
> > Let take for instance a light wooden plane such as Mark Hunts
> > Insight.  I think it weighs like 9lbs 8 oz with a 140 sport in it.
> > Guessing at the conversion straight to electric it would now weigh
> > around 9 lbs 14 ozs running 5s4p dual packs and an AXI setup.  If the
> > air frame was reengineered in a way to allow it to be built around 9
> > lbs and remain as strong but because of the lower overall weight go to
> > a smaller battery say the 5s3p packs and still see the same
> > performance and duration?
> >
> >
> >
> > I may be changing too many variables for a straight answer but the
> > general idea I think you get.  Just some thoughts (how about an all
> > depron 2 meter) hmm.
> >
> >
> >
> > Thanks for your thoughts positive or negative.
> >
> >
> >
> > Chuck
> >
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