[NSRCA-discussion] Fwd: Electric Weight Proposal Logic andRationale

[Richard Strickland]

For most guys, myself included, just want to use the existing airframes and
not have to sweat being super-light and it costing up the wazoo to get
there.  Plus the very light airframes don't stand up to much abuse to where
one little prang puts you over the limit.  You certainly have a good point
about the unintended consequences of a change--but how many guys would go
for it?--you don't see that many bipes out there now primarily because they
are a pain in the ass to deal with when in heavy practice mode for a guy
after work...

Richard
  -----Original Message-----
  From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of
Davel322 at comcast.net
  Sent: Thursday, June 21, 2007 12:36 PM
  To: NSRCA Mailing List
  Subject: Re: [NSRCA-discussion] Fwd: Electric Weight Proposal Logic
andRationale


  Richard,

  I think in many respects trying to compare electric / glow is like
comparing apples and oranges.....so having a blanket set of rules that is
absolutely equal (and fair) for both is not going to happen.

  The "most fair" methods are going to be too complex - ie, calculate
average power loading and wingloading for average electric and glow models
over the course of an average flight...and then structure the rules to
ensure equality of the averages for glow and electric.  And as technology
and equipment changes....the rules would have to continually change to
maintain parity.

  My electric Prestige is 7.5 lbs without batteries.....for another 2.5 lbs
of airframe, .5 lb of motor, and .5 lb of radio gear, I could easily build a
bigger (but still 2M) plane with performance that would absolutely obsolete
any of the current day 2M stuff (and probably double the pricetag as well).

  Dave
    -------------- Original message --------------
    From: "Richard Strickland" <richard.s at allied-callaway.com>

    I know I sound like a broken record, but: The IC airplanes are weighed
without fuel--the electrics should be weighed with out their fuel.  Give or
take a little for the tank and not splitting hairs--but it simply is not
fair the way it is set up now.  I'd still like to know how that decision was
made--so they could just un-make it...seemed pretty arbitrary to me...no
rule change involved--it appears someone just said this is so.  Somebody
straighten me out, please.

    Richard Strickland
      -----Original Message-----
      From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Ron Van Putte
      Sent: Thursday, June 21, 2007 11:09 AM
      To: NSRCA Mailing List
      Subject: [NSRCA-discussion] Fwd: Electric Weight Proposal Logic and
Rationale


      I got the following from John Fuqua.  He is going to submit a proposal
to increase the weight limit for electric-powered airplanes to 11.5 lbs.  I
suggested to him that he "float" his rationale by the NSRCA Discussion List,
to get some feedback.  Here is his response.


      Ron Van Putte



      Begin forwarded message:


        Date: June 21, 2007 10:40:36 AM CDT
        To: "Ron Van Putte" <vanputte at cox.net>
        Subject: Electric Weight Proposal Logic and Rationale


        Now that I am flying electrics I have come to realize the penalty
that electric planes have when being built that gas planes to not have.
That building penalty is significant under the current rules.  Electrics
must be built lighter, to include paranoid attention to everything used -
wood, paint, fittings, etc., - all to make weight.  Much more of a concern
than gas planes.  Also I remember many instances at the NATs when we were
weighing airplanes, when the contestant was doing all he could do to meet
weight with a gas plane to include cleaning the fuel residue inside and out.
A lot of gas planes were weighing in at 10lb 11oz, 10lb 11.9 oz, even one
that was only a few grams under 5 kilos.   Then they get to add a minimum of
16 to 20 ozs of weight by fueling up (and there is no limit to fuel
capacity).  Takeoff weights are 12 lbs or more.   This situation seems
bizarre and illogical when yo! u put s ome thought into it.  Electrics have
a finite weight and gas planes are open ended at Takeoff.   Even though the
2005 NSRCA survey did not support an electric weight increase it occurred to
me that the survey did not offer any logic or rationale as to why some
increase would be justified or not.  I have attempted below to come up with
a reasonable compromise on electric weight allowance.  I believe the
rationale supports an increase but it would be nice to have NSRCA membership
look at it to find the fatal flaw in the rationale before it gets submitted.
The two paras below are taken from the proposed change.   Lets put it out
and see what the discussion list comes up with.

        John

        Change paragraph 4.3 Weight and Size page RCA-2 to read:  No model
may weigh more than 5 kilograms (11 pounds) gross, but excluding fuel, ready
for takeoff.  Electric models are weighed with batteries and are allowed an
additional 8 ounces for a total of 11.5 pounds ready for takeoff.   No model
may have a wingspan or total length longer than two (2) meters (78.74
inches).



        Logic behind proposed change, including alleged shortcomings of the
present rules.  State intent for future reference.

        Today's 2 meter RC Aerobatics fuel powered aircraft typically use
fuel tanks with a 20 fluid ounce capacity.  A 20 fluid ounce Crank Tank
containing 25% Cool Power Pro Pattern fuel was tested.  The fuel weighed
17.3 ounces.  Allowing for variation in tank sizes and fuel type a
conservative weight of 16 ounces of fuel on average seems appropriate.  This
means that an allowable takeoff weight for fuel powered aircraft is at least
12 pounds.   Assuming that all fuel is consumed during the flight, the
average weight for the aircraft is 11.5 pounds.  By restricting electric
powered aircraft to the takeoff weight of unfueled aircraft an unfair weight
penalty is being arbitrarily imposed against the electric model.  By
allowing electric aircraft an AVERAGE flying weight of the fuel powered
aircraft, flying weight equity is restored.


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