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Post by hghost on Feb 6, 2014 0:55:27 GMT 1
SC came stock tail heavy if that is what you are asking ? That's what I was asking. Seems improbable. In general they come a tad nose heavy which is more suitable for a trainer. I'm puzzled what would do that. I added larger wheels, re-inforced the battery box area and LG area with balsa wood and still had to add weight in the nose to get it level I think it was 11 cents...2 Nickels and 1 penny....I taped them into the nose to get it level I even added screen wire to cover the openings in the cowl ( for looks ) taped the inside of the cowl for strength, taped leading and trailing edges, taped the body and even the Rear stab areas. Took me awhile to get it level, it was either tail heavy or I added weight and the nose dropped...but who would have thought 11 cents worth, levels it out perfectly. I tried several things at first weights, small batteries...to heavy one way or then the other...took a little change out of my pocket and that cured that... It was odd. Flies great tho. |
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Post by flydiver on Feb 6, 2014 16:36:19 GMT 1
Ahh, not stock. You added reinforcements, therefore weight to various places.
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Post by hghost on Feb 6, 2014 21:29:20 GMT 1
Ahh, not stock. You added reinforcements, therefore weight to various places. Fly I had hoped adding Larger wheels and some thin balsa wood around the battery box-LG area would have leveled the plane out, but it still didn't. In fact I thought the Mods were done not only for strength , but to help bring COG more foreword, cause i thought the plane came tail heavy naturally ? By reading what you have said guess that is not always the case. I did add a larger tail wheel, but that wasn't until after first CG check, it made it more tail heavy, why I thought I had to add weight in the cowl, later. I struggled with it back and forth for a couple days till i got it perfect. Seems a piece of tape one way or the other threw it off, some slightly, some more. But come to think of it while I am typing this I did add clear tape to the rear stab and on most of the plane before I checked the CG the first time , I did do that, now that i remember. Cause I started not to Modify it at all, then changed my mind, to add larger wheels and strengthen around the batt-box and LG area. That may have caused it to be tail heavy at first most likely.....gee...never thought of that until now. So yeah not real stock after all. In fact I covered the Horizontal and vertical stab first and the wing edges. figuring they would be first to get damage in a crash ? Hummm....did not think of that till now....LOL Fly ya knew all along something was up....wish my memory was better, would save me allot of headaches and others reading my ramblin about it. |
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Post by flydiver on Feb 6, 2014 21:45:34 GMT 1
I did add clear tape to the rear stab and on most of the plane before I checked the CG the first time.......In fact I covered the Horizontal and vertical stab first.
Take a look at where the CG point is. Then remember your basic lever physics. You put a LOT more weight behind the CG than in front of it on a MUCH longer lever arm. A gram in the tail probably needs 3-5 grams in the nose to compensate.
The battery box mod and larger wheels are essentially ON the CG so will have little balancing effect beyond adding weight. You can't affect a teeter-totter much by sitting on the fulcrum point.
FWIW the stabs are not worth covering at all. They are already plastic coated foam. More won't help much and as you see can cause a different kind of problem. A couple bits of carbon or bamboo embedded across the weak spot in the tail is about all you should do back there. A larger tail wheel won't hurt much as long as you go light.
I don't know where people get the idea that they need to mummify the Cub in tape before they fly it. It simply is not really useful and can be detrimental. It's now heavier, must fly faster to stay up making control more difficult for the newbie, and will crash harder due to more weight.
Just like I told the guy with the "Taxi Cub" he just painted....even paint can mess up the CG.
Reinforcements are best placed judiciously for max effect and minimum weight. I've seen people reinforce their planes until they literally would not fly.
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Post by Knackered Sailor on Feb 6, 2014 23:22:05 GMT 1
Mine came nose heavy, had to trim to maximum and take a couple of turns in on the control rod to achieve level flight on half throttle.
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Post by hghost on Feb 7, 2014 2:15:46 GMT 1
You can see by these Pics how it was tail heavy and then level These were taken at final CG adjustments, so they do not tell the entire story It was after all Mods were done . This one shows tail-heavy  And this one shows the few cents setting on the nose ( actually 12 cents -I think i stated 11 before? couldn't remember.)  This one shows plane level  |
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Post by hghost on Feb 7, 2014 2:25:33 GMT 1
Strange how you do something and not realize the effect it has. I know better, ( made those mistakes years ago ) mind doesn't work as well, but still I know better. I keep notes or try to most times.Also why i ask so many times over and over.
I did not know about CG back then, built it, tried to fly it, results many shattered dreams. After continued building and getting more information over the years I saw some issues and mistakes I made and learned from my mistakes ( i thought ).....now i know to check and recheck and not assume .I also ask and re ask to make sure.
After getting back into the Hobby, swore would not make those mistakes. So far so good. Can't remember everything, but i do go back and read and re-ask whatever it takes to ensure it is right before I continue.( when i remember...lol )
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Post by flydiver on Feb 7, 2014 3:01:56 GMT 1
Mine came nose heavy, had to trim to maximum and take a couple of turns in on the control rod to achieve level flight on half throttle. You don't want to approach it that way. CG first > then trim and adjust as necessary. |
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