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Old Mar 04, 2015, 03:42 PM
Flying Object Crash Tester
United States, WA, Tacoma
Joined Jun 2013
337 Posts
Try this one, flaps should work
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Old Mar 11, 2015, 03:47 PM
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Skyepuncher's Avatar
United States, OH, Zanesville
Joined Sep 2012
391 Posts
Flew one batt Mon after work. Warm, but breezy. All good. Landed, & taxied over
to My truck. All good. Go home, put stuff in the garage. It`s warm enough, now.
Got to lookin`. Rudder is way off center. Long story short. Bottom hinge pulled
clear out of the fuse, & off to the side. Hmmm. straightened the hinge material,
& got it back in place. Now what? Didn`t want to glue it. Ran a straight-pin
thru it, & installed the smallest screw I could find in My bins. Doubt it would even
register on scales that We use. Had to use magnification/w/lights to do it, &
My tiniest phillips head.
Scott
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Old Mar 22, 2015, 03:38 PM
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isle of man
Joined Aug 2003
181 Posts
late to the game here, but I had a CC and want another but!! my previous one would climb horribly above half throttle and needed a lot of down elevator to keep level. CG was as far forward as the battery bay allows and still it wanted to climb. did I have a duff one??
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Old Mar 22, 2015, 04:53 PM
Registered User
United States, MD, California
Joined Jan 2014
156 Posts
Where was your CG relative to spec? Are you sure you haven't got the CG too far forward?

It's counterintuitive but with forward CG the plane will require up elevator trim for level flight at, say, half throttle. Therefore, as you go above half throttle the up elevator trim will become more pronounced and require down elevator input to counter it.
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Old Mar 22, 2015, 05:32 PM
Gopher huntin' stick jockey
turboparker's Avatar
East Bethel, MN USA
Joined Jul 2009
13,222 Posts
Quote:
Originally Posted by locoworks View Post
late to the game here, but I had a CC and want another but!! my previous one would climb horribly above half throttle and needed a lot of down elevator to keep level. CG was as far forward as the battery bay allows and still it wanted to climb. did I have a duff one??
Nope. As Woody noted, you had the CG too far forward in the first place, which is why it nosed-up under power. Moving the CG even further forward simply made the problem much worse. Balance the plane & adjust the CG to the factory recommended starting point of 18mm aft from the LE. Take her up & trim for level fight @ 75% power. That will solve your problem. BTW - you can't use a cradle-type balancer that's designed for larger planes to balance these UMs, unless it has a means of balancing the cradles - as it only takes a few grams of cradle imbalance to throw the reading way off at this scale. See the pic below for a simple way to make a UM plane balancer.

Also, be sure to thoroughly read my CC handling checklist & flight-trimming guide - including the tips on flying a scale Cub & proper use of flaps: http://www.rcgroups.com/forums/showp...29&postcount=1

Joel
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Old Mar 22, 2015, 06:37 PM
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Skyepuncher's Avatar
United States, OH, Zanesville
Joined Sep 2012
391 Posts
Quote:
Originally Posted by turboparker View Post
Nope. As Woody noted, you had the CG too far forward in the first place, which is why it nosed-up under power. Moving the CG even further forward simply made the problem much worse. Balance the plane & adjust the CG to the factory recommended starting point of 18mm aft from the LE. Take her up & trim for level fight @ 75% power. That will solve your problem. BTW - you can't use a cradle-type balancer that's designed for larger planes to balance these UMs, unless it has a means of balancing the cradles - as it only takes a few grams of cradle imbalance to throw the reading way off at this scale. See the pic below for a simple way to make a UM plane balancer.

Also, be sure to thoroughly read my CC handling checklist & flight-trimming guide - including the tips on flying a scale Cub & proper use of flaps: http://www.rcgroups.com/forums/showp...29&postcount=1

Joel
Thats a lot of reading Joel. Please point out the part about the CG.
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Old Mar 22, 2015, 07:01 PM
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Kryton's Avatar
Canada, BC, Delta
Joined Feb 2013
192 Posts
E-Flite UMX Carbon Cub SS

You really need to read the whole thing there's a lot of really good information in there.
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Last edited by Kryton; Mar 22, 2015 at 07:13 PM.
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Old Mar 22, 2015, 10:17 PM
Gopher huntin' stick jockey
turboparker's Avatar
East Bethel, MN USA
Joined Jul 2009
13,222 Posts
As Kryton noted, you need to read all of it, as everything I wrote is important if you wish to experience the true potential of this impeccable little Cub. Besides, it's not actually all that much to read. Takes less than 30 minutes. That's nothing compared to most of the technical manuals I have to read. Many of 'em are well-over 500 pages of fairly small text.

Joel
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Last edited by turboparker; Mar 22, 2015 at 10:31 PM.
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Old Mar 23, 2015, 09:20 AM
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isle of man
Joined Aug 2003
181 Posts
Quote:
Originally Posted by WoodyInMD View Post
Where was your CG relative to spec? Are you sure you haven't got the CG too far forward?

It's counterintuitive but with forward CG the plane will require up elevator trim for level flight at, say, half throttle. Therefore, as you go above half throttle the up elevator trim will become more pronounced and require down elevator input to counter it.

thanks for the response. it does make sense. I assumed ( quite wrongly perhaps ) that with the battery in its little pocket would set the CG correctly. there isn't the room to move the battery for and aft like with the pitts and geebee where there is lots of space. and if there was room I'd need scale hands to position it down the hole. I also tried a 240mah battery ( heavier ) which may have added to my issues. I wrote it off big time trying to tow the little ASK21, it was rather funny for everyone that didn't have $$ invested . in short I gave it full power and it took off smartish and started to climb fast, the glider was barely off the floor so in a very short space of time the towline was pressing down on the tail plane and at that point all the down elevator on the planet was having no effect. we ended up in the position where the cub was stalled/prop hanging with the glider hanging like a caught fish about 8 feet AGL. the glider released and ended up nosing in at around a 40 degree angle onto asphalt with no damage. the cub still on full power ( my fault ) was now coming back inverted above me at whatever height and instead of rolling out of it I thought I'd have the height to just hold in up elevator and do half a loop out of it. I was wrong. in a matter of seconds it hit the asphalt at about the same 40 degrees but full power. the motor mount snapped, the right wing snapped at a previous fix by the canopy and the left wing sheared in half ripping the wires from the servo and leaving it hanging by the lighting wires only. the turtle deck let go and the whole nose area looked like an accordion for the second time. the struts were also ripped out of the fixing points on the fuse and that itself was ripped apart. I just removed what was left that worked and the rest received a memorial service.

I will get another as I so want to see the glider towed succesfully, I will just have to check the CG and will also read the checklist linky and do what needs doing for a happy flight. I might try towing the glider with my night visionaire in the meanwhile.
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Old Mar 24, 2015, 08:00 PM
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Canada, BC, Delta
Joined Feb 2013
192 Posts
E-Flite UMX Carbon Cub SS

Quote:
Originally Posted by turboparker View Post
As Kryton noted, you need to read all of it, as everything I wrote is important if you wish to experience the true potential of this impeccable little Cub. Besides, it's not actually all that much to read. Takes less than 30 minutes. That's nothing compared to most of the technical manuals I have to read. Many of 'em are well-over 500 pages of fairly small text.

Joel

1985. I started investing $1000.00's in this hobby thinking I was smart enough to fly right out of the box. (My dumb a$$.) My firstborn was a 3 cannel trainer with the option to make a 4 channel, so me thinking I'm smarter than the average bear. I make her a 4 channel 40 size glo power to crash and that's exactly what I did. Built crash Rebuild crash rebuild crash. Rebuild fly crash again I can't land yet. Next I buy a Goldberg cub with floats & flaps and spend 3&1/2 months building, (what a beautiful model) only to put in on the lake and taxi around get the feel of her when the wind picks up and I'm in the air, panic and cut the throttle, bang into the steep bank off the lake, rekitting my beautiful cub. Now I could go on an on an on about learning the hard way. So what I'm saying in a long winded way, is no matter what plane you buy read Joel's checklist, it will save you time, grief and $$$$$$
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Last edited by Kryton; Mar 24, 2015 at 10:02 PM.
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Old Mar 24, 2015, 09:57 PM
Diverted by planks
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South Florida
Joined Dec 2010
5,746 Posts
Flew my CC for the first time in a long time this morning. Quiet field, no wind, just doing lazy slow circuits... good fun.
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