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  1. #1
    Senior Member turbopilot's Avatar
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    Feb 2010
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    Lightbulb EX3 Lite

    I have owned a Carbon Cub SS ELSA since 2010. My typical mission is me and half fuel (12 gallons) (fun mode). My current CC SS empty weight is 948 lbs with full Dynon HDX panel, 26" tires and full Beringer brake/landing gear system. In the "fun mode" this machine has a power to weight ratio of 6.7 lbs/hp, significantly lower than a P51 at 7.1 lbs/hp. So for the last 9 years I have come to truly appreciated the joy of flying a CC at very low weights.

    I would like to move up to the FX3/EX3. The fuel injected engine and G-Series controls are a very attractive enhancements. So I am considering building an EX3 Lite. I can do without the constant speed prop (estimated to weight net 30 lbs less if substituted with a Catto fixed pitch prop) and 44 gallons of fuel (each 10 gallon tank estimated to weigh 8 lbs in tankage before calculating unusable fuel, saving 16 lbs over 44 gallon tank). So to begin building an EX3 Lite it would appear it could start 46 lbs lighter without the CS prop and extra fuel. In addition I would put the Beringer brakes, wheels and Alaska Landing Gear System on the EX3 Lite saving an additional net 10 lbs of weight.

    So all up it would appear that I could build an EX3 Lite with an empty weight about 56 lbs lighter the listed empty weight on the web site. But here is the mischief. I am getting conflicting information as to whether the web site listed empty weights are near reality. I have heard some estimates suggesting the base empty weight of the FX3/EX3 could be up to 100 lbs more than the listed weight of 1023.

    Just for comparison the web listed empty weights for each CC model are 892 lbs for the SS, 982 lbs for the FX2/FX3 and 1023 lbs for the EX3/FX3. So on paper the FX3/EX3 base empty weight is +140 lbs over my current CC SS ELSA. Using these numbers it would appear I could build an EX3 Lite with a base empty weight of 976 lbs, just 84 lbs more than the base empty weight of a SS. Of course this is all before adding back the significant weight of bush tires and avionics. By adding "light" avionics and 26" tire there is a chance of getting an EX3 Lite built at around 1,000 lbs empty weight.

    An 84 lb weight addition sounds like a worthwhile trade off to get the fuel injected engine and G-Series controls. A EX3 Lite could even be reasonably certified as an ELSA, ready to be flown at higher weights if the LSA regulations change to allow added weight and speed.

    My problem is that I am having a hard time verifying whether the listed empty weights on the web site are real. In theory the FX3 and EX3 empty weights should be the same at 1,023 lbs and that is how they are listed on the web site. However, the EX kit shows it delivered without avionics or the 44 gallon fuel option while the FX3 comes the "World VFR" panel as standard equipment along with 44 gallons of fuel as standard. So as delivered, before options, the FX3 and EX3 base empty weights must be different.

    The other problem in the mix is that CubCrafters no longer publishes the weights associated with various options. When I ordered my last two Carbon Cub SS's the web site contained detailed information about option weights. So far I cannot get that information for the current options offered on the Carbon Cub models.

    I doubt anyone (including CubCrafters) has actually built and FX3/EX3 without any options, so the actual base empty weight has to be an estimate.

    There is now a fair amount of experience in the builder community. Is 1,023 lbs a good estimate of base empty weight of an EX-3? If not, what are the guesses as to the actual base empty weight? Thanks for your help.
    Last edited by turbopilot; 07-09-2019 at 08:12 AM.
    Bob Anderson, CC11-00435, N94RA

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