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Old Sep 07, 2012, 04:31 PM
Magic Valley Airforce
United States, TN, Jackson
Joined Feb 2008
19 Posts
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J3 Cub takeoffs - 76" Goldberg about 20 yrs old

I have searched as best I can and can't find any info on this subject.

I recently purchased a Goldberg J3 76" wingspan and installed an OS 61 with 12-6 prop it flys great once in the air but is all over the runway to get there. I have set all control throws per the book and have almost 100% neg expo [Futaba Trans] and still can't control it. Just have to point it and jump on the throttle to get it airborne I have plenty of toe in on main gear and she is balanced per manual.

Any suggestion would be appreciated.

Gary
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Old Sep 07, 2012, 05:28 PM
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United States, SD
Joined Aug 2010
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Cubs tend to be very touchy on the rudder, it might be that you need to get used to it, or you can move the clevis to control horn hole farthest from the rudder.
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Old Sep 07, 2012, 08:23 PM
Magic Valley Airforce
United States, TN, Jackson
Joined Feb 2008
19 Posts
Quote:
Originally Posted by kylerdinger View Post
Cubs tend to be very touchy on the rudder, it might be that you need to get used to it, or you can move the clevis to control horn hole farthest from the rudder.
kylerdinger,

Good suggestion, I will try it next flight.

Gary
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Old Sep 07, 2012, 10:14 PM
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Fla.
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If you can, use " Hi & Low " rates on your rudder. Most people try to use to much rudder when taxiing. I've found that practice your taxi is also really needed. Try to not taxi to fast and just keep it in a straight line. Practice, practice, practice .

I like to start slow with full up elevator for a few feet , get straight and add throttle slowly letting the elevator out so the tail wheel comes up and the plane gets level. Keep it level for a few feet then slowly pull a little elevator in and make a slow scale TO.

There's nothing as Pretty as a scale Cub take off . Practice and it will come, just DON'T rush it and ENJOY the results. Good Luck, ENJOY !!! RED
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Old Sep 07, 2012, 11:13 PM
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Joined May 2012
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I built the same plane last summer for a friend. He also has floats for it. Only engine he has is a OS .91FS. Serious over kill, even for a float plane!
All Cubs want to ground loop, just the nature of the beast. After you have taken off a few times you get it figured out. Not really a trick to it, low rate rudder so you can't over control it, about 10% up elevator to keep the tail wheel on the ground and roll out slowly so you can steer it. Once it's up on step you should be OK.
Food for thought, if a Cub is such a ground looping fool on land, why does it make such a good float plane??
Just something to think about.
The toe in is a big help!!
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Old Sep 07, 2012, 11:49 PM
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United States, SD
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I had my H9 cub on floats, and it was ground looping (or water looping) alot. I think I got that taken care of, but I have some other issues with it no though.
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Old Sep 09, 2012, 12:58 AM
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United States, CA, Clovis
Joined Mar 2004
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Yep... what they said. Its a matter of finding your timing and touch between throttle/rudder and everything else. Its just a plane that has a bit more of a learning curve then some others. Its easy to take the "high-wing" Cub for granted.. although a very nice smooth flying plane for sure.. there are a few different things about it. Good luck.
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Old Sep 09, 2012, 02:47 PM
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Originally Posted by DGrant View Post
Yep... what they said. Its a matter of finding your timing and touch between throttle/rudder and everything else. Its just a plane that has a bit more of a learning curve then some others. Its easy to take the "high-wing" Cub for granted.. although a very nice smooth flying plane for sure.. there are a few different things about it. Good luck.
A Fresno pilot!! I sure miss your field, loved the IMAA and racing events they held there.
A word about the Cub. If you just can't get the take off with the plane then you can bend some wire and make up a wider gear of your own. The gear is narrow and it has that long wing so it wants to ground loop, just the nature of the beast. The toe in helps but it took me several take offs to get the feel of the cub. Hammering the throttle and lifting off is what most of us did to get them off the ground but it's just asking for a stall. I got mine!! Then I learned to control it but I had a lot of aborted take offs. Every time it started to get ahead of me I cut power and started over until I had it figured out. I also had those plastic tabs on the end of the wing to save the covering and wore the left one almost off. Either make up a wider gear or relax and spend some time getting the feel of the plane. The one I built for my friend looks so real in the air the way he flys it. Makes me want another one.
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Old Sep 09, 2012, 06:51 PM
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Quote:
Originally Posted by Roo man View Post
I have searched as best I can and can't find any info on this subject.

I recently purchased a Goldberg J3 76" wingspan and installed an OS 61 with 12-6 prop it flys great once in the air but is all over the runway to get there. I have set all control throws per the book and have almost 100% neg expo [Futaba Trans] and still can't control it. Just have to point it and jump on the throttle to get it airborne I have plenty of toe in on main gear and she is balanced per manual.

Any suggestion would be appreciated.

Gary
I have a Goldberg Cub with a 91. If I give full throttle on takeoff it'll do a nasty ugly ground loop. I give half throttle and it takes off smoothly - easy as pie. Once airborne I punch it. With a 61 try 1/2 throttle or perhaps a bit more. Have patience (don't use full throttle) and it'll take off on it's own.
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Old Sep 09, 2012, 06:54 PM
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United States, MN, Brooklyn Center
Joined May 2009
746 Posts
My experience with the Goldberg Cub and the Sig Smith Miniplane are the same as Gene's....

After you have been flying it for a while you will find the "technique" that will work for you.

It is cool when you figure it out.

The Goldberg Cub is a blast to fly, by the way. You're in for a real treat!

Brian
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Old Sep 09, 2012, 11:51 PM
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United States, CA, Clovis
Joined Mar 2004
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Quote:
Originally Posted by Gray Beard View Post
A Fresno pilot!! I sure miss your field, loved the IMAA and racing events they held there.
Yep... I would be one of those... thanks Gray Beard... I've flown a few Cubs out of there.. haha.. We've been fortunate to hold many different activities over the years.. its been kind of slow the last few years though. Still a strong club though.. without a doubt.. There's alot of people to thank for the facilities.. but thank you for noticing.. I'll share the kind words with the guys. ..

Back to topic.. there is some very good info here.. I think he's going to do fine with this Cub.. Just a matter of the "touch".. thats all.
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Old Sep 10, 2012, 12:22 AM
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I had a heck of a time with the Smith!! Understatement!
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Old Sep 10, 2012, 10:37 PM
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USA, OK, Warr Acres
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Have you tried full right aileron to get it up un one wheel? JUST KIDDING
You didn't say if you're flying off grass or pavement, if you have some grass to fly from it will help slow things down a bit
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Old Sep 11, 2012, 06:46 AM
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Florida
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You definitely need to have toe in on the gear. If not, it will wander all over the runway on take off.
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Old Sep 12, 2012, 10:05 PM
rvlevy7
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United States, NJ, Clinton Township
Joined Sep 2012
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Quote:
Originally Posted by Roo man View Post
I recently purchased a Goldberg J3 76" wingspan and installed an OS 61 with 12-6 prop it flys great once in the air
Gary
I have 1988 Cub J3 Goldberg 76" wingspan. Yes it was nice fly but elevator sensitive control because long wing as weight.
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