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Thread: New EX first few flights and a few questions.

  1. #1
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    Default New EX first few flights and a few questions.

    Good day all. I have had the privelage of flying a beautifully made Carbon Cub EX for the owner down here in South Africa. It is one of only three in South Africa and the first I have flown, needless to say I think it is a stunning machine and am loving flying her! This EX was built by a fastidious local pilot who has done a stunning job with the build, the attention to detail and care is amazing. In the initial flying phase I have picked up a few niggles and wanted to see what y'all thought about them:

    1. The controls seem very stiff (uncomfortably so), is this normal or is it possible that the control cables are over tight?
    2. The back windows seem to rattle rather a lot and make a racket when flying, is there a mod to secure them slightly better?
    3. The aircraft is quite drafty without any seals on the windows or doors, I see that there is a STC for sealing the doors and windows, is this very efffective?
    4. The stick seems uncomfortably short, I have to cock my wrist at an unusual angle to get a full grip on it and if I want to adjust the trim it is a odd wiggle about to get my thumb to activate the trim, not much fun when popping the first notch of flaps. This is probably the biggest issue I have with the aeri and am wondering if this isn't why the controls feel so stiff?
    5. The stall warning seems to come on at too high a airspeed, (+-20mph above the stall)

    Thanks in advance for the help!

  2. #2
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    Default Re: New EX first few flights and a few questions.

    Quote Originally Posted by Iain View Post
    Good day all. I have had the privelage of flying a beautifully made Carbon Cub EX for the owner down here in South Africa. It is one of only three in South Africa and the first I have flown, needless to say I think it is a stunning machine and am loving flying her! This EX was built by a fastidious local pilot who has done a stunning job with the build, the attention to detail and care is amazing. In the initial flying phase I have picked up a few niggles and wanted to see what y'all thought about them:

    1. The controls seem very stiff (uncomfortably so), is this normal or is it possible that the control cables are over tight?
    2. The back windows seem to rattle rather a lot and make a racket when flying, is there a mod to secure them slightly better?
    3. The aircraft is quite drafty without any seals on the windows or doors, I see that there is a STC for sealing the doors and windows, is this very efffective?
    4. The stick seems uncomfortably short, I have to cock my wrist at an unusual angle to get a full grip on it and if I want to adjust the trim it is a odd wiggle about to get my thumb to activate the trim, not much fun when popping the first notch of flaps. This is probably the biggest issue I have with the aeri and am wondering if this isn't why the controls feel so stiff?
    5. The stall warning seems to come on at too high a airspeed, (+-20mph above the stall)

    Thanks in advance for the help!
    Hi Ian.

    I'll see if I can pitch in and help out with some of the "niggles".....

    1. Most likely the stiff controls are from the torque tube being too tight in the clamps that hold it (2 of them). I know there were some issues since the tolerances on that material was .005 and some were a little on the large side and needed to be sanded. Here is a link to a thread about that http://forum.cubcrafters.com/showthr...ht=torque+tube. What you can do for now is to shim up the 2 clamps holding the torque tube down. You can use some thin material like a beer/soft drink can cut down to a small piece and just place the shims on either side of the clamps, then retorque. Keep shimming until loosens up. Later as that tube wears in some, you can remove those shims if need be.

    2. Window rattle fix here http://forum.cubcrafters.com/showthr...ght=chuck+ryan. see post #134. My windows didn't rattle do I didn't do it.

    3. CubCrafters does have a seal kit available. It's just some foam weatherstrip material (the sell it at Home Depot as well). You can seal around the windows where they meet the frame (would have to remove the plexi).

    4. Buy an XCub (or FX/EX3). They have the big sticks. :-)

    5. You adjust where the stall switch activates by loosening the 2 screws on either side and then slide the entire switch and cover UPWARDS (towards the top of the wing) to make it activate at a slower airspeed.

    Good luck!
    Last edited by Daveembry; 11-07-2017 at 05:14 AM.

  3. #3
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    Default Re: New EX first few flights and a few questions.

    Thanks very much for the help. We will have a look at the torque tube and see what happens.

    Is there really no mods/adjusmtments one can make to the stick? I just feel that it really is far to low!
    Thanks again

  4. #4
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    Default Re: New EX first few flights and a few questions.

    Quote Originally Posted by Iain View Post
    Thanks very much for the help. We will have a look at the torque tube and see what happens.

    Is there really no mods/adjusmtments one can make to the stick? I just feel that it really is far to low!
    Thanks again
    I agree. Aperantly CC does too since it’s longer in all current Cubs

  5. #5
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    Default Re: New EX first few flights and a few questions.

    Can one install a new ex-3 stick in a origional ex cub?

  6. #6
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    Default Re: New EX first few flights and a few questions.

    Iain... in addition to Dave’s suggestions, here is what I experienced with overly tight control forces. Once tightened to recommend tension, the ailerons were extremely stiff. We traced the cables and found one in the left wing had been routed under a rib lace. We rerouted the cable which helped, but still too stiff. I orginally tightened the aileron cables on the high side of recommended anticipating some stretch (40 +/- 5lb). I reduced the tension to the low side and got significant improvement. Still stiff, but much more manageable.

    regarding stick height... hopefully you are following the Infinity Grip postings. I’m going with Pete’s recommendation and a Ray Allen G205. Peters hanger is near mine so I can learn from his install. I did have to order a new EX stick as it’s nearly impossible to remove the existing trim without destroying it.

    Hope this helps.

  7. #7
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    Default Re: New EX first few flights and a few questions.

    Thanks Chip, all info is most welcome. I was concerned about how stiff the aileron control cables were and I suspect that the chap who has built this one has done something similar to the situation you have described. I haven't been following the thread but will try dig it up as I feel a longer stick would make a world of difference.
    Cheers
    Iain

  8. #8
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    Default Re: New EX first few flights and a few questions.

    Some caution here folks. Please be aware that lengthening a pilot control stick, even just a little by using added grip length, can significantly increase the loads in the flight control system as was confirmed on the Xcub design/certification effort. The EX & EX-2 control systems are designed and tested for the stick length provided with the kit. Xcub & our new EX-3 / FX-3 models include longer sticks/grips and the flight control structure was strengthened to accommodate this, and structurally tested for validation.

    XCub-LaunchEdition-21.jpg
    Last edited by Pat Horgan; 11-14-2017 at 09:38 AM.
    Patrick Horgan
    President
    CubCrafters | Yakima WA

  9. #9
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    Default Re: New EX first few flights and a few questions.

    Thanks Pat, surely the extra control forces would only be an issue above Va or if slaming into the stops?

  10. #10
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    Default Re: New EX first few flights and a few questions.

    Quote Originally Posted by Iain View Post
    Thanks Pat, surely the extra control forces would only be an issue above Va or if slaming into the stops?
    Thanks for your question, Iain. At CubCrafters, whether a certified aircraft or experimental kits, we analyze and test all of our airframes and systems to proven standards.

    Control system structure (including: controls, mounts, pulleys, cables, rods, hinges, stops, etc.) is evaluated to withstand various load inputs from the control stick. Yes, load cases include being against the stops but we also look at many other conditions, such as: pilots acting together, pilots opposing each other, additive autopilot loads, hinge moments, and many other conditions. Any added control stick length will increase the load inputs (it's a lever arm) and the totality of possible affects on all the related structure.

    We really look forward to sharing with you (very soon...) all of the engineering changes made to make our newest generation Carbon Cub, the FX-3 & EX-3. This aircraft has higher gross weight and an expanded flight envelope. In the case of Xcub and FX-3/EX-3, which both have longer pilot control sticks, control system structure was "beefed-up" in several places to accommodate the length change.
    Patrick Horgan
    President
    CubCrafters | Yakima WA

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