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Post by higgsbosonman on Feb 16, 2011 23:01:03 GMT 1
I don't know what happened. i just maidened my plane, and was having a good time. my cub will go full vertical with the 480 brushless ;D , but i lost control not even half way through the pack. my wings are unreenforced, and at one point i saw them warp like they were made of noodles. than it just started to bank right uncontrollably, and i ended up putting it down into a snowbank. nothing broke, but the aileron servo on the left wing was loose (note to self: don't use tape to hold your servos in even three layers won't do it.) i think this is one of the reasons for the crash, but it doesn't explain the fact that when going WOT the plane would pull it's nose up and spiral like a corkscrew. can anybody explane what forces are messing with my plane? I'm grounded till i get this bug resolved.  |
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Post by pauliepilot on Feb 17, 2011 20:57:46 GMT 1
Do u use the struts???
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Post by toff on Feb 17, 2011 21:31:28 GMT 1
Ooh...Ooh.....( Hand in the air), 'Please sir, Please sir!' "Yes, Toff, Go ahead.."
'Well sir, is it because the wings have no support, from the sound of it the aileron servos are not affixed properly, the angle of attack on the wing is designed for lift, which, coupled with a powerful motor just pulls the aircraft up and over unless enough downthrust/ down trim is applied, in short, some of the problems I and a few others have had with the brushless uprade?'
"No Toff, it isn't - but good try! B+ for you!"
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Post by higgsbosonman on Feb 25, 2011 21:44:43 GMT 1
i have wing struts, yes. my servos were held in with a layer of scotch tape (tore loose on the left wing!), and are now held in with a generous helping of hot glue. no wing fortification untill a little while ago, added two 1/4 inch square hardwood dowels to the wing, because i didn't have carbon fiber and didn't know how to bend that so i still had some dihedral. the wing lift thingy is probably right. what angle do you have your mount at toff? i just used the factory angle. i totally forgot i made a thread.  |
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Post by toff on Feb 26, 2011 0:20:44 GMT 1
I used a coupla popsicle ( Is that spelled right?) sticks under the rear rear of the wing. this reduces the wings angle of attack ( and therefore lift), and helps to stop the plane doing the up'n'over with a brushless motor ( worked for me anyhoo!)
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Post by higgsbosonman on Feb 27, 2011 17:49:31 GMT 1
Ok. i'll try that. how many sticks did you use? my dad's got a whole box of tongue depressors, which are just big popsicle sticks (7/8 inch instead of 3/8 inch wide). does this make the plane nose over on take off more often? pics.  you can see the wooden reinforcements and my odd ESC location. it gets really, really good cooling though.  |
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Post by toff on Feb 27, 2011 22:09:17 GMT 1
Hit'n'miss for me. I use 2. I'd advise using 1 at a time just to see the effect, instead of using lots at once just 'cos I said so.
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Post by higgsbosonman on Mar 2, 2011 0:06:55 GMT 1
the following pictures are what happens if your wing breaks in half and detaches from the plane at three hundred feet.  the thing crumpled to bits.  the impact was so hard, it tore the elevator off because the steel geared servo wouldn't shift foreward as the rest of the tail broke off. the pushrod has a 30 degree bend in it, too.  what is this buisness of the cowls being so flimsy? i havn't broken mine yet (knock on wood), and it just survived hitting asphalt at over seventy miles per hour.  the nice gaping crack in the side of the fucelage. Epoxy is being used to fix it (used half of a syringe already), and 5/8 inch hardwood dowels are going into the wings. the 1/4 inch ones just couldn't handle it. no, this wasn't pilot error. the ailerons stayed in place where they had been when the leads tore loose from the reciever, and they had less than five millimeters of control throw. i was basically flying level when it happened, at 50% throttle. |
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Post by SCC on Mar 2, 2011 0:43:42 GMT 1
Supercub wings do not break at 50% throttle unless you had a defective wing before it went up. or your brushless set up does a 100mph at 50%.  Looks like you had a similar break on the other side of the wing, how did that happen? Edit: I have read the rest of the thread. |
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Post by Dillzio on Mar 2, 2011 4:49:48 GMT 1
I used a coupla popsicle ( Is that spelled right?) sticks under the rear rear of the wing. this reduces the wings angle of attack ( and therefore lift), and helps to stop the plane doing the up'n'over with a brushless motor ( worked for me anyhoo!) Nice mod, I never would have thought of that. I've accomplished the same thing by making my plane a bit more nose heavy than usual. I can change how nose heavy my plane is with the GPS, I can either not use it at all, mount it under the nose (behind the cowl) or on top of the cowl. I find that without the GPS it flies much more like the stock super cub, in that at full throttle it just wants to nose up, so much so that it will stall unless you give it some down elevator. With it set on top of the cowl, i find that it's a much faster plane, and will only very slowly gain altitude at WOT unless I you pull up a bit with some elevator trim, FANTASTIC for low-altitude high-speed fly bys :-). With it mounted under the nose, I find it's a nice mixture of the two. Any tendency to nose down while coming in for a landing is more than compensated for by the flaps (I still have some down elevator mixed in on the flaps channel). I strongly suspect that your wing was fractured in a previous crash, as SCC mentioned, probably during the same thing that broke the other side of the wing. Fractures in thick foam can be difficult to detect as they may look like nothing at the surface, but it's actually a very deep crack. Sometimes the only way to find them is by bending the foam to see if any cracks open up. I'm quite sure that I must have some fractures in my plane, particularly the tail-area of the fuselage, but everything is still wrapped tight in profilm so it prevents it from getting any worse. I actually broke my wing in half a few months ago, including two of the carbon spars running through it (did I forget to tell you guys about that one?)  I had to take the profilm off to fix that, as well as replacing some servos and lights, and I found a bunch of cracks in the foam I never new were there. |
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Post by higgsbosonman on Mar 3, 2011 0:02:52 GMT 1
it looked totally fine, and the wood spars were added only a week before. the crack on the other side of the wing was from a failed take off, it went up, and dropped a wing and crashed, snapping the wing in half. the side that didn't break hadn't hit the ground, so i don't know how a crack could have formed than. it hit a tree, but again, the wing was fine. may explain the flutter of the wings on the flight before this but after the tree.
my motor is a power up 480 brushless, with a 10x5 prop. i did some lazy aerobatics before hand, but other than that, yeah, it broke at fifty percent throttle.
repairs have started. i broke the little plastic battery box, and am attempting a fix, but what's a better alternative than the wire set up? how do people repair the gear after that breaks? besides the landing gear, it needs a new motor mount, and i already replaced the horizontal and vertical stabilizers. the wing may get carbon fiber, since my wooden spars are being STUPID and not bending to the contour of the wing, even after soaking in water for a few hours.
when did your wing break, dillzio? mid-flight or on landing?
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Post by toff on Mar 3, 2011 0:12:52 GMT 1
Higgs, fix the wing up with epoxy, and then, your just going to have to do it...
" Hey Dad, buddy, pal'o'mine... I REALLY need some carbon spars. PLEEZE!!!"
Walking round on your knees at this point, whilst begging might also help!
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Post by renard80 on Mar 3, 2011 0:29:54 GMT 1
. i broke the little plastic battery box, and am attempting a fix . . . I have broken the battery box a few times and discovered the best glue to mend its "waxy" plastic is epoxy. Do you have "Araldite" over there? That's what I use now for battery box repairs. |
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Post by Dillzio on Mar 3, 2011 11:04:17 GMT 1
when did your wing break, dillzio? mid-flight or on landing? Neither, while crashing. If you want to keep your dihedral, you need to cut the channel for the spars deep towards the wing tips, and shallow in the middle. |
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Post by higgsbosonman on Mar 3, 2011 22:43:51 GMT 1
actually, i've now got some leverage with my mom because she wreaked one of my hand drawn comic books (last one was 17 pages, with HiggsBoson Man ), so i think i'll force her into buying all the new parts for my cub. i'm really @#%%$ off about it, because they take like 20 hours of work. we don't have Araldite here. there's nothing but epoxy and superglue at my hardware store, and it's all other brands. my dad isn't exactly a pal. he's been so busy his boat hasn't gotten off the trailer in 2 years. the only time we talk is at the dinner table, and i try during TV shows, but he tells me he's watching the TV. he'll ocassionally drive me out to the high school to fly my cub, but that hasn't been for a couple months. i think i'll just ditch the dihedral. my wing can't take much more mutilation. it already looks like crap. |
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Looks like you had a similar break on the other side of the wing, how did that happen? Edit: I have read the rest of the thread.
I had to take the profilm off to fix that, as well as replacing some servos and lights, and I found a bunch of cracks in the foam I never new were there.