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Thread: Down-wind takeoffs

  1. #1
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    Default Down-wind takeoffs

    Ok, y'all did a great job on the landings...

    Now, how about down-wind takeoffs? My little strip out here (which isn't all that little) looks to be pretty much usually a downwind takeoff. The choice is either takeoff down wind...or take off up hill...and we are talking a height gain of probably 90 feet in 1500 feet...or pretty darn steep. My VW bug will get up to around 30 mph coasting down the hill.

    So, the POH says that at 70 degrees and 7200 feet, with a 15 mph tailwind, the takeoff run at gross is right at 600-650 feet. I've got 1500 feet with no important obstacles beyond that (the junipers are probably 10-15 feet high...and they continue to "fall off" into the valley. Add the down hill aspect, and I betcha I will beat that.

    Based on the numbers, it looks like a no-brainer. I would plan on keeping the tail down and doing the "soft field" takeoff...to keep directional control early in the run, but of course, given the gobs of power we have (even at this altitude) that is probably a meaningless concern.

    Comments? There are no CC instructors out here...and our airplane is sufficiently unique that a typical SuperCub guy is not all that useful.

    Thanks in advance.

    Jim

  2. #2
    Senior Member Dan L's Avatar
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    Default Re: Down-wind takeoffs

    Hi Jim,

    I like the idea of asking about take-off's too.

    I don't have experience with your downwind - downhill scenario. It sounds like the situation often seen with glacier take-off's. I've been a back seater for a few of those.

    With normal take-off's I always pull two notches of flaps and get the tail up quickly. I'd be interested in what others use for this type of take-off as well; one notch, two, three, none?
    Flying Carbon Cub EX #11 since 2011

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    Default Re: Down-wind takeoffs

    Great addition, there. Hell, I never use more'n one notch of flaps on takeoff. Do tell, folks...

    Jim

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    Senior Member Clay Hammond's Avatar
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    Default Re: Down-wind takeoffs

    With a 1500 feet, clear departure, and terrain that falls away...I don't see any problem. You should be airborne long before it is an issue, depending on load and wind of course. My only concern, and one you might just have to embrace as unanswerable, is whether during an aborted takeoff you'll be able to get it stopped before running off the end. Chance for a brake induced nose over might be higher too due to the downhill lie also, depending on speed, load and braking power. When you go to takeoff just make sure you are fully committed with no factors present potentially leading to an abort.

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    Default Re: Down-wind takeoffs

    Quote Originally Posted by Clay Hammond View Post
    With a 1500 feet, clear departure, and terrain that falls away...I don't see any problem. You should be airborne long before it is an issue, depending on load and wind of course. My only concern, and one you might just have to embrace as unanswerable, is whether during an aborted takeoff you'll be able to get it stopped before running off the end. Chance for a brake induced nose over might be higher too due to the downhill lie also, depending on speed, load and braking power. When you go to takeoff just make sure you are fully committed with no factors present potentially leading to an abort.
    Thanks, Clay. Probably answerable...the "runway" levels off for the last about 300 feet. Could do most of the stopping then. Otherwise, gonna be running through the junipers off the end. Probably survivable, but gonna need to truck the airplane out of there.

    Overhead photo of the layout. Runway proper runs from left to right...really uphill in the last 2/3rds.
    Attached Images Attached Images

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    Senior Member randylervold's Avatar
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    Default Re: Down-wind takeoffs

    You might consider trying it both ways and see what feels better and allows the greatest margin for errors or the unexpected. Under normal circumstances the Carbon Cub should be able to do either way with no problem, but as we all know it's all about "the unexpected". ;-)
    Randy Lervold

  7. #7
    Senior Member Dan L's Avatar
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    Default Re: Down-wind takeoffs

    Quote Originally Posted by Jim Harper View Post
    Great addition, there. Hell, I never use more'n one notch of flaps on takeoff. Do tell, folks...

    Jim
    I too would like to hear what technique others use for takeoff.

    As I've mentioned before I roll in full forward trim for landing. I leave all of that trim for takeoff and pull two notches of flaps. I try to leave neutral stick until the tail starts to rise on its own and then push a little forward stick for better visibility. About this time it wants to fly.

    For me this seems to offer the quickest takeoff from any surface.

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    Default Re: Down-wind takeoffs

    I've been playing more and more with 2notch takeoffs...and three notch takeoffs. I like the two notchers...not so much the three. The airplane flies so quickly, its hard to tell which is better. I think it is off faster with two notches. One of these days I'll try to get scientific.

    As an aside, Dan L, I owe you a huge vote of thanks. Using the three notch/tail low/wheel landing techniqe you have suggested has revolutionized my landings. Last couple-three landings using that technique have been tremendous...control, nice touchdown, easy stopping. Just revolutionary for me. I used to hate three notches on landings...doing a full stall landing I really didn't know when the landing was over...don't know how to better express it...seemed like I was down, but it danced a lot. Now I pin it down and brake with the flaps going up...smooth and very satisfying.

    Thank you very much!! I love this forum.

    Jim

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    Senior Member Dan L's Avatar
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    Default Re: Down-wind takeoffs

    Jim, glad to read that the tail-low wheel landing technique is working for you. In my opinion it is much, much easier to spot land by wheel landing too.

    I know not everyone will agree but for me, especially off-airport landings are shorter landing like this. I keep some weighty items in my extended baggage so braking can be heavy without the tail wanting to come up.

    When it is gusty though I like a flatter AOA and higher airspeed at touchdown. You don't want to get behind the power curve when the conditions are unstable.

    But this thread was about takeoffs. Any other opinions?

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    Wink Re: Down-wind takeoffs

    I love the picture of your runway.
    You are very lucky to have such an isolated area to live and play in.
    Where are you exactly, if you don't mind saying?
    Bill

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