[NSRCA-discussion] Fwd: Electric Weight Proposal Logic and Rationale

[John Pavlick]

Ron, 
 What's he worried about, doesn't he have a Black Magic? <VBG>

John Pavlick
http://www.idseng.com
  ----- Original Message ----- 
  From: Ron Van Putte 
  To: NSRCA Mailing List 
  Sent: Thursday, June 21, 2007 12:08 PM
  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 you put some 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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