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Thread: Weight

  1. #1
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    Default Weight

    (I posted this in another thread but have since thought that it would be better addressed here)

    I don't (yet) have a CC but DO have this question:

    In filling out the 'order form' I noticed that the empty weight is 885 and MAX empty weight is 900. It seems that to stay within SLSA limits you can't even add the 26" tundra tires or much of anything else.

    Also, I ran across this article which seems to refute the importance of 'empty weight' Your thoughts? (see below)

    Thanks

    Ron


    "Some commentators stated that lacking a definition of maximum take off weight, aircraft with fairly high performance characteristics could meet the definition of light-sport aircraft by limiting the approved weight and payload of the airplane. The FAA considers this a valid concern and has provided some additional constraints on the weight as detailed below.
    The maximum weight of a light-sport aircraft is the sum of :
    (1) Aircraft empty weight;
    (2) Weight of the passenger for each seat installed;
    (3) Baggage allowance for each passenger; and
    (4) Full fuel, including a minimum of the half hour fuel reserve required for day visual flight rules in FAR 91.151(a)(1)"


    This definitively states the definition of ”maximum takeoff weight” of a light-sport aircraft as is used to determine what may be considered a light sport eligible aircraft and no other definition, or use of the term “maximum weight” as found in the F.A.R’s or elsewhere may be substituted at will.
    Not Gross weight, Maximum Gross weight, Maximum gross takeoff weight, or any of the other terms that are tossed around. This weight, “maximum takeoff weight”, as defined specifically by the FAA for LSA issues, as the sum of (1), (2), (3), and (4),

  2. #2
    Member Steve Hamblin's Avatar
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    Default Re: Weight

    FAR 1.1 defines a light sport aircraft as having a gross weight of 1320 on wheels, 1430 on floats.

    FAR 1.1 defines nothing for empty weight or useful load, etc. This is where the ASTM rules come into play.

    An S-LSA is required to have a minimum useful load-this equation is found in ASTM F2245. This equation takes into account how many people and how thirsty the engine is.

    This formula is:
    Useful Load = # of seats x 190 lbs plus 1/2 the max continuous horsepower.

    Example: Carbon Cub=(2 x 190) + (1/2 x 80). The minimum useful load for the Carbon Cub is 420 pounds.

    Using the FAA's definition of an LSA of 1320 gross, subtract 420 from 1320 and you get 900. 900 lbs is the maximum empty weight of the aircraft.

    However, an S-LSA aircraft (already found to be in compliance with the S-LSA rules to get certified) can then be converted to E-LSA. Now, some of the limitations that come with the S-LSA rules (such as minimum useful load and the trickle down calculation of empty weight) no longer apply, you are now only bound by FAR 1.1 that defines gross weight maximums (and other things as well, but the topic is weight).

    I hope this helps-Do let me know if I can help clarify at all.

    Steve
    Last edited by Steve Hamblin; 10-21-2010 at 10:29 AM.

  3. #3
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    Default Re: Weight

    Quote Originally Posted by Steve Hamblin View Post
    FAR 1.1 defines a light sport aircraft as having a gross weight of 1320 on wheels, 1430 on floats.

    FAR 1.1 defines nothing for empty weight or useful load, etc. This is where the ASTM rules come into play.

    An S-LSA is required to have a minimum useful load-this equation is found in ASTM F2245. This equation takes into account how many people and how thirsty the engine is.

    This formula is:
    Useful Load = # of seats x 190 lbs plus 1/2 the max continuous horsepower.

    Example: Carbon Cub=(2 x 190) + (1/2 x 80). The minimum useful load for the Carbon Cub is 420 pounds.

    Using the FAA's definition of an LSA of 1320 gross, subtract 420 from 1320 and you get 900. 900 lbs is the maximum empty weight of the aircraft.

    However, an S-LSA aircraft (already found to be in compliance with the S-LSA rules to get certified) can then be converted to E-LSA. Now, some of the limitations that come with the S-LSA rules (such as minimum useful load and the trickle down calculation of empty weight) no longer apply, you are now only bound by FAR 1.1 that defines gross weight maximums (and other things as well, but the topic is weight).

    I hope this helps-Do let me know if I can help clarify at all.

    Steve
    Thanks Steve,
    Crystal clear explanation. Looks like I will 'convert' to ELSA. Now I am *REALLY* excited about a cc!

    Ron

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