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great planes cub kit

Old 08-27-2015, 06:36 AM
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rye
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Default great planes cub kit

hi
i build a G-P cub 76 " wing it flys great and lands great, but when i take off i have to hold full left rudder to get it to go straight and it still want to go right before she take to the air is this a traded of this plane some say its a hand full to take off ,any thing i can do to fix this she running a satio 56 thanks
Old 08-27-2015, 03:23 PM
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Double check your engine OFF SET on the plans . Cubs are a pain to take off anyway and a lot of left rudder is pretty normal with most of them . Other wise " Practice, Practice , Practice . ENJOY !!! RED
Old 08-28-2015, 01:11 AM
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RBACONS
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It is normal to require "RIGHT" rudder on take off, not Left. If you are holding left rudder on take off then there is likely something wrong with the landing gear set up or the engine thrust.
Old 08-28-2015, 04:22 AM
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Originally Posted by RBACONS View Post
It is normal to require "RIGHT" rudder on take off, not Left. If you are holding left rudder on take off then there is likely something wrong with the landing gear set up or the engine thrust.

That's what I was thinking, too. If left rudder is required, the engine thrust, landing gear, or both, require adjustment.
Old 08-28-2015, 07:20 PM
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A Cub, and several other tail-dragger type planes will sometimes need a nudge of "RIGHT" rudder.. and sometimes more then a nudge... but its always right rudder.... so yeah... listen to these guys, and check your thrust alignment, and everything they said... as if its actually taking left rudder, you got something out of wack....

Either that or... maybe the original poster is confused on his "left/right" directions... as if he would have said it takes right-rudder... well ... thats pretty normal.. especially if one has no experience with a Cub.. They can be very tricky until you learn the timing/inputs of throttle/rudder/elev..etc.. Once you get the touch.. it gets easier.. they will still keep you on your toes though.
Old 08-29-2015, 02:40 AM
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Be sure and have some toe-in in the landing gear. Any toe-out almost guarantees a ground loop when you try to take off. Yes, you will definitely need some right and down thrust on the engine. On mine I needed about 3 degrees right and 5 degrees down thrust.

Last edited by Rodney; 08-29-2015 at 02:41 AM. Reason: correct toe in directions
Old 08-30-2015, 07:44 PM
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If you are needing left rudder, I'll give you 10 to 1 odds your landing gear isn't straight. You need to get your main wheels straight first, then get the tail wheel tracking right. I think the value of toe in is debatable. My Cub is set up perfectly straight, and I love how it handles. That plane was an absolute monster to take off with though when I first got it because the main gear wheels were turning a bit to the right. I had the tailwheel set to make the plane roll straight, but of course as the rudder gained authority during acceleration the plane would go all squirrely on me. Ground handling on Cubs is a multi page conversation for a lot of guys, but in my experience it's not really a big deal if your wheels are set up properly. An Ugly Stick taildragger will let you get away with a sloppy setup, but a Cub won't.
Old 08-31-2015, 11:04 AM
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My 2 cents worth of "wisdom" on Cub takeoffs is the incorrect slamming of the throttle from zero to full throttle in one micro second. This upsets the path the airplane will take even before you get started. You're chasing the plane right from the start. The correct way, especially with Cubs, is to gently feed in throttle to get the plane moving and continue to progressively feed in more throttle while controlling the direction of the plane with rudder. At the beginning of the takeoff roll hold a little up elevator to hold the tailwheel on the ground for steering control and as you began to pick up speed release the elevator to neutral or near neutral (maybe a very small bit of up elevator to prevent a nose over). Once the tail is up you are steering it with just the air passing over the rudder and by now you should be at full throttle waiting to gain enough airspeed for safe take off. Don't rush lift off, especially with a Cub, as you can easily stall on take off, and then you will have your hands full trying to recover from a stall when you are only 36" off the ground ! Been there and done that.

Last edited by 52larry52; 08-31-2015 at 11:48 AM. Reason: missing word
Old 08-31-2015, 02:24 PM
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Usually being too heavy with the throttle results in a ground loop to the left though. If a Cub turns right at all on takeoff it either has massive amounts of right thrust or the landing gear is wonky.
Old 08-31-2015, 06:43 PM
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Yes jester you are correct, the plane would go to the left. My "2 cents" was aimed at Cub and taildragger takeoffs in general not what may be the OP's problem with his plane going to the right. I agree his trouble is likely in the engine thrust angle and/or main gear alignment. The OP still has not come back on here to to clear up if his plane is going to the right or his "other right".
Old 09-01-2015, 02:46 PM
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jester_s1
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I really doubt it's the thrustline. I have 3 degrees IIRC of right thrust in my H9 Cub and it will still go hard left on takeoff if I let it. I think he'd need 5 degrees, maybe more to cause that kind of problem.
Old 09-01-2015, 03:55 PM
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The tried and true test of landing gear set up issues is to turn on the transmitter and plane, and give the plane a push by hand on a flat floor. If it doesn't roll straight, you have landing gear alignment issues to correct.
Old 09-01-2015, 05:57 PM
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jester_s1
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That's not conclusive though. If your main gear is crooked, you can adjust your tail wheel to compensate and make the plane roll straight. That was the issue I had on my Cub; it would roll straight and then go all crazy as I accelerated. I fixed the problem by taping a 4 foot long stick to each wheel so I could precisely measure the angle the main gear was at. I took measurements at both ends of the wobble too so I could get the actual angle right. It took about an hour of tweaking and measuring to get both axles perfectly straight with the fuselage. I was surprised the next time I taxied it how badly the tail wheel had been turned to compensate. So then I got the tailwheel aligned properly with the new landing gear setup, and the plane has handled beautifully on the ground ever since. It's still a Cub no doubt, but it's now predictable and easy to manage.

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