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

[Ron Van Putte]

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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