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Thread: EX3 Lite

  1. #1
    Senior Member turbopilot's Avatar
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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, CC11-00316, N382RA

  2. #2
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    Default Re: EX3 Lite

    Bob, Iím not really big personally on weight shaving, etc as Iím building and playing around with my EX3ís and not doing any STOL stuff or competition but..... Iíll pitch in what I know.

    First, (and this is a question)....... would not the 30 extra lbs for the constant speed prop be more than offset in takeoff wt penalty due to the ability to have it jump off the ground in the fine pitch setting? I think the take off distance would be much shorter with the fine pitch vs the fixed pitch (plus you cruise faster and burn less gas.....seems like a win win?)

    All my carbon cubs have had all the options and the Ex2 weighted about 1020 with 29Ē tires. The EXí3ís have both weighed about 1140 with 31ís.

    Also note the 7 more horsepower in the EX3 with the 187 (listed.... I think itís more than that) hp vs. 180 hp.

    just a couple thoughts.

    Quote Originally Posted by turbopilot View Post
    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.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  3. #3
    Senior Member turbopilot's Avatar
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    Default Re: EX3 Lite

    Quote Originally Posted by Daveembry View Post
    Bob, Iím not really big personally on weight shaving, etc as Iím building and playing around with my EX3ís and not doing any STOL stuff or competition but..... Iíll pitch in what I know.

    First, (and this is a question)....... would not the 30 extra lbs for the constant speed prop be more than offset in takeoff wt penalty due to the ability to have it jump off the ground in the fine pitch setting? I think the take off distance would be much shorter with the fine pitch vs the fixed pitch (plus you cruise faster and burn less gas.....seems like a win win?)

    All my carbon cubs have had all the options and the Ex2 weighted about 1020 with 29Ē tires. The EXí3ís have both weighed about 1140 with 31ís.

    Also note the 7 more horsepower in the EX3 with the 187 (listed.... I think itís more than that) hp vs. 180 hp.

    just a couple thoughts.
    Appreciate the thoughts. Don't know if anyone has put a fix pitched climb prop on an FX/EX3. Would be interesting to see the difference in climb against the constant speed prop. Since I rarely go long distances with my Carbon Cubs, cruise performance is not a big deal for me. The obvious advantage about not having a constant speed prop (aside from weigh savings) would be to keep the aircraft certifiable as an LSA. Should the LSA regulations change one could always add it later.

    Other than 31" tires what other "heavy" options did you have on the EX3's that weighed 1,140 lbs empty?
    Bob Anderson, CC11-00316, N382RA

  4. #4
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    Default Re: EX3 Lite

    Bob,

    I attached a spec sheet here that list all the items on this last plane. Biggest items probably extended fuel; extended baggage with carpet; oregon aero seats front and. Back; G3X touch with transponders, radios, autopilot with servos; tires; 1.75 brakes; stainless steel brake lines; Baby bushwheel, etc.


    Quote Originally Posted by turbopilot View Post
    Appreciate the thoughts. Don't know if anyone has put a fix pitched climb prop on an FX/EX3. Would be interesting to see the difference in climb against the constant speed prop. Since I rarely go long distances with my Carbon Cubs, cruise performance is not a big deal for me. The obvious advantage about not having a constant speed prop (aside from weigh savings) would be to keep the aircraft certifiable as an LSA. Should the LSA regulations change one could always add it later.

    Other than 31" tires what other "heavy" options did you have on the EX3's that weighed 1,140 lbs empty?
    Attached Files Attached Files
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  5. #5
    Senior Member turbopilot's Avatar
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    Default Re: EX3 Lite

    Quote Originally Posted by Daveembry View Post
    Bob,

    I attached a spec sheet here that list all the items on this last plane. Biggest items probably extended fuel; extended baggage with carpet; oregon aero seats front and. Back; G3X touch with transponders, radios, autopilot with servos; tires; 1.75 brakes; stainless steel brake lines; Baby bushwheel, etc.
    Thanks Dave. That is a loaded EX3. Your empty weight squares with the empty weights of a couple of loaded FX3's coming down the line in Yakima. Pretty clear a well equipped EX3/FX3 is going to come in around 1,140 lbs empty. So 117 lbs over base empty weight. The 31" tires and G3X/autopilot must account for about 75 lbs over base airplane.
    Bob Anderson, CC11-00316, N382RA

  6. #6
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    Default Re: EX3 Lite

    Bob, sent you a PM.

    Andrew

  7. #7
    Senior Member turbopilot's Avatar
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    Default Re: EX3 Lite

    Been getting off line questions about the Beringer ALG system I have on my 2014 CC SS.

    Here is a thread documenting my experience.
    Bob Anderson, CC11-00316, N382RA

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