[NSRCA-discussion] Long - RE: Weight

Thu Jun 4 08:17:35 AKDT 2009

Honestly, I understand (and agree) with the intention to allow the "cheap
electric", but it is no different than trying to tweak the rules for the
"cheap gas engine" and won't (my opinion, with substantial history to back
it) work- 
- why should the rules be tweaked to essentially allow someone the latest
greatest (electric) without paying for it (either with time, or $$$, or
experience)?  The latest greatest always cost more - that is the nature of
competition.
- I truly believe the time spent researching, designing, crafting,
submitting, and implementing such a proposal will largely be wasted because
the process is relatively slow and can not possibly keep up with the rate of
change in electrics as technology advances.
- Anyone who wants to try electric - go right ahead - and fly a current day
design at a slight weight disadvantage at local comps (most guys don't go to
the NATs anyway) - no one is going to ask or care about a couple ounces over
11 lbs.  And if they do decide to go to the NATs, they can suck it up and
buy 1 expensive pack for official flights and the scale.

With the understanding of the intent to allow cheap electrics, the
unintended consequences of any rule change needs to be carefully evaluated
prior to submitting a proposal.  In this case, the unintended consequence
will be the opportunity for the TOP LEVEL electric designs to grow
substantially in size and weight, which will drive the cost up for all
competitors (glow and electric) to compete with the new performance
standard.  The average plane is influenced by whatever the TOP LEVEL stuff
is - that is why both electric and glow TOP LEVEL stuff has always been
right on the limit of whatever the rules are at the time, and that is the
way it will always be - again, it is the nature of competition.

The top level electrics right now weigh well under 11 lbs......10 lbs is
quite possible with electric monoplanes, which is why some are able to sneak
biplanes in under 11 lbs - of course this is by shaving every ounce off the
airframe (reducing it's lifespan and making it relatively fragile) and
pushing the lipos harder (also reducing it's lifespan).  So when you look at
8.7 lbs considering the weight of the electrics that are marginally
overweight (with the Zippy packs and AXI), the unintended consequence is the
guys that have 7.5 lb airframes now have 1.2 lbs of additional weight to add
to make the plane bigger - and you know it will be used, and probably along
the lines of - 
- 6-8 oz for structure
- 3-4 oz for more motor (more power)
- 4-5 oz for more lipo (which would still be rated the same 5300 mah, but be
heavier to allow more voltage under load, thus delivering more watts through
the course of the flight - and it will be called a "High Power Prolite", or
"High Power AEON", whatever.)
- 1-2 oz more for bigger servos and more RX battery

And 2 years after the 8.7 lb rule is introduced, there will be a cheap copy
of the "High Power Prolite" will be available and it will weigh 5 oz more,
and the desire will be to raise the 8.7 lbs to 9.2 lbs.

Allow 5.5 kg (12 lb) or 6 kg (14.3 kg) airframes, and yes, you will have
DA50 powered stuff that is competitive with current day designs, but it will
not be competitive with the YS built for 6 kg airframes for the same reason
gas is not competitive with glow now.

Allow 5.5 kg weight limit, and you instantly solve the problem of all the
guys that are a couple oz over the current 5 kg weight limit.  And the new
designs will grow, and in 1-2 years, the new designs will be showing up a
couple oz over the 5.5 kg limit.

It may be true that for the TOP LEVELs of competition that any airframe is
obsolete in 3 years......BUT.......changing the rules to allow 15 lbs
airframes will obsolete (immediately) not only the airframes, but the
powerplants and servos.....and up the horsepower requirements substantially
which will increase the noise (only measured at the NATs) and require
substantially more cost to reduce the noise (to achieve 94/96 db at the
NATs).

All of the above is escalation no different than what we've seen in the past
-
- "we" started with .61 cubic inch (10 CC) limit and 5 kg......the only
practical limit was the displacement.
- "we" allowed 120 4C (big mistake, short sighted, or should have been
continually adjusted as competition 4Cs developed).  Airframes grew and cost
went up....some airplanes actually exceeded 2M (which was not yet a limit).
- "we" allowed unlimited engines to, in part, cover up the mistake of the
120 4C, and, in part, to allow cheap gas engines (another big mistake, again
short sighted).  The 2M rule went into place because that was essentially
the "largest" plane in existence at the time.  The airframes got bigger
again (fuse volume), and cost went up again, and the practical limit to
airframe size became the 5 kg weight limit.

Of course we also have the noise limit - that is really a separate issue -
but - it is worth noting that larger airplanes require more power, and more
power is more noise (or more expense to keep the noise from increasing).

"Wouldn't it be nice if"........is a dangerous lead in to rule changes with
unintended consequences.  The gas engine, the heavier lipo, the heavier
motor, the heavier airframe, etc.....will all forever be less competitive
because the limits will always be pushed by the airframe/powerplant that has
the best power to weight ratio, and that will always cost more, and always
be more sensitive to weight conscious building techniques.  No change in the
rules will ever allow parity for equipment that does not have the best power
to weight ratio.

Someone else made the point that they perceived the less the rules change,
the more available airframes and equipment are (2nd hand) - I couldn't agree
more.  Stop changing the rules to allow (intended or not) higher performance
airframes, and the "old" ones won't be obsolete so quickly.

Personally, after a lot of research and planning, I switched to electric in
2006....and the expense was big.....especially because I had perfectly good
glow stuff, and maintained glow and electric for about 1 year.  To date,
I've built 3 electric airframes (1 Abbra, 2 Prestige), and between them I
have run 12 different motors of different brands, weights, in/out runners,
and just about every mounting configuration you can think of.  The majority
of the motors have been < $300, and I've always used the Castle 85HV (which
I think has always been and still is the least expensive ESC available for
the job).  My planes have weighed anywhere between 9 lbs 13 oz and 10 lbs 14
depending on the configuration.  If I had the time, $$$, resources, etc, I'd
design and build my own stuff right up to the limit, whatever that limit
might be.  As I do have limits (as most of us do), I'll get as close to what
I think optimum performance is, and it may or may not be pushing the limits
(for whatever reasons). 

In the past 3 years, I've spent a huge amount of time on email, phone,
forums, in my shop, in others shops, etc....working with people on how to
assemble electric pattern stuff....and most are not using the most expensive
airframes or equipment, and all are under 11 lbs.  Bottom line is that you
can not take the largest, cheapest, and heaviest of each respective
component and have a sub 11 lb electric OR glow plane.  Nor do you need to
have the most expensive and lightest example of each component to be
competitive.  You do need to research, plan, and make educated decisions.
No offense to anyone with an 10 lb 18 oz plane....they do exist....and most
are being happily flown, and most can make weight for the NATs if the time
is spent in advanced.

Regards,

Dave

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
verne at twmi.rr.com
Sent: Wednesday, June 03, 2009 1:53 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Weight

Derek,
We've discussed raising the weight before and it's always been voted down. I
believe for good reason. Dave Lockhart has steadfastly argued that raising
the weight limit will inevitably increase the size of our planes, obsoleting
anything that preceded it. I agree with him. 

What I'm trying to do is make it more feasible for someone wanting to try
electric to be able to do so without having to buy the most expensive
equipment available. For example, at a contest last weekend, a friend and
fellow pattern pilot had a set of Zippy packs that weighed roughly 5.5
ounces more than my FlightPower packs. Pretty much the same difference when
compared to Andrew's TP packs. The Zippy's as we all know, were less than
half the cost. I know for sure that my friend would have made weight with my
FP's or Andrew's TP's, but he couldn't afford that after all the other
"electric" purchases. 

What I'm going to propose once I have it all worked out, is that electric
airplanes weigh LESS than glow planes and be weighed without their "fuel",
just like glow. The Rx battery will have to be in the plane, just like glow.
Yes, I realize that there are UBEC's out there but I don't know of anyone
who trusts them with the kind of current we're running. In any event, my
preliminary research indicates that roughly 8.7 pounds should be just about
right, but I want to make sure before I submit the proposal.

Verne

---- Derek Koopowitz <derekkoopowitz at gmail.com> wrote: 
> Verne,
> 
> When I was at the CIAM meeting in March one of the proposals which was
> passed by the helicopter guys (F3C) was to modify the weight limit for
their
> helicopters effective 1/1/2010.  Here is the new wording:
> 
> a) WEIGHT: The weight of the model aircraft (*with *fuel *or *batteries)
> must not exceed *6.5 *kg.
> 
> Unanimously approved by the Plenary Meeting. Effective 01/01/10.
> 
> I'm going to feel out the rest of the F3A sub-committee members to see if
> there is interest in raising the F3A weight limit to 5.5kg.  What does
> everyone think about this?
> 
> -Derek
> On Wed, Jun 3, 2009 at 7:51 AM, <verne at twmi.rr.com> wrote:
> 
> > Bill,
> > I've been working up an AMA rules proposal to address that very issue.
> > Unfortunately, it won't be up for vote by the contest board anytime
soon. In
> > the meantime, there's one area you didn't mention in the glow to
electric
> > comparison and that's that an electric plane doesn't need as much
internal
> > reinforcement because there's virtually no vibrational effects to
contend
> > with that you do with glow. That equates to lighter airframes being
> > acceptable as well as small, light, lipo packs to power the Rx and
servos.
> > An 8 minute e-flight typically uses about 50 mah. The same flight in
glow is
> > typically 200+ mah. All that aside, most electric pilots will tell you
that
> > making weight in electric is generally a pretty expensive proposition
with a
> > limited number of 2 meter planes available that are usually
vacuum-bagged
> > composite affairs. In addition, your best chances for making weight will
> > also necessitate the lightest and generally most expensive motors and
> > batteries. There are exceptio
> >  ns, and I'm sure we're about to hear about most of them, but I'll be
able
> > to point to just as many examples of guys that fly overweight at local
> > contests where they know they won't be weighed and the only thing
they're
> > really guilty of is not spending the extra money that the lightest
batteries
> > and motors cost. In every other way, the planes they're flying are the
same
> > as the ones they're competing against. The proposal I'm working on is
not
> > self-serving because my planes make weight, but getting there is both
too
> > expensive and unreasonable, in my opinion. My proposal won't be to allow
> > electric planes to weigh more, it'll require that they weigh less, but
> > without the "fuel". The proposal will take into account that electric
motors
> > are inherently lighter than their glow counterparts as well as the
reduced
> > structural requirements. It will limit the mah of permissible packs to
> > control that end of the equation and there's already a voltage limit on
the
> > books which is fine as it
> >  stands. I'm currently doing survey work at the contests I go to to see
> > where everybody is at weight-wise and will post my proposal on this list
> > soon. After that, it's up to all concerned to voice their opinions to
their
> > respective Contest Board reps.
> >
> > Verne Koester
> > AMA District 7
> > Contest Board
> >  ---- Bill's Email <wemodels at cox.net> wrote:
> > >  I am certain this has been beaten to death while I was off doing
other
> > > things, but can anyone explain this:
> > >
> > >
> > > Rule 4.3: Weight and Size. No model may weigh more than five (5)
> > > kilograms (11 pounds) gross, but excluding fuel, ready for takeoff.
> > > Electric models are weighed with batteries.
> > >
> > > Why can't an electric "deduct" the equivalent of 16 ounces of fuel??
Is
> > > a plane without fuel rally "ready for takeoff"??
> > >
> > > I know it is likely a direct copy of the FAI rule, but it makes no
> > > logical sense. IC powered planes are weighed without fuel and can
weigh
> > > right at 11 pounds. Add fuel and it could add another 10 to 12 ounces
of
> > > weight. That's OK. But if an electric with batteries weight
> > > 11.0000000000000001 pounds it is overweight by the rules.
> > >
> > > Put another way, what does a YS and full fuel weigh compared to a
> > > motor+ESC+batteries?
> > >
> > > Hacker C50 14XL = 18.2 ounces
> > > Hacker Spin 99 ESC = 3.7 ounces
> > > 10S packs = +/- 43 to 46 ounces
> > >
> > > Weight w/o batteries = 21.9
> > > AUW w/batteries = 66.9 ounces
> > >
> > > YS 1.70 = 33.6 ounces (955 grams)
> > > AUW with tank and fuel = 45 ounces +/-
> > >
> > >  So I can see an argument that the electrics have a weight advantage
> > > when it comes to just the motor and ESC. But with "fuel" electric is
at
> > > a 20 ounce disadvantage.
> > >
> > > So if I build a plane for electric I need to build it 20 plus ounces
> > > lighter than if I was going to put a nitro motor in it. How does that
> > > make sense. I know I am missing something important here, so educate
me.
> > >
> > >
> > >
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