My new cub

[Dillzio]

Apr 28, 2010 4:57:42 GMT 1 Legot said:

So that's how it should work, it's the same concept as putting flaps on a y-harness with programable throws wit the servos facing the same direction.

Ah crap, I didn't get a Y-harness for flaps!

Oh well, at least I can buy SOMETHING from my LHS

[killioughtta]

Apr 28, 2010 11:33:01 GMT 1 Dillzio said:

Apr 28, 2010 4:57:42 GMT 1 Legot said:

So that's how it should work, it's the same concept as putting flaps on a y-harness with programable throws wit the servos facing the same direction.

Ah crap, I didn't get a Y-harness for flaps!

Oh well, at least I can buy SOMETHING from my LHS

just use one servo dude. why are you going to use 2 servos for flaps? it's one uniform movement up or down. got to go; im on vacation and the wife is somewhere around here.if she catches me on scc on the android she'll kill me! lol ps twitter.com/killerwin

[Dillzio]

I've been thinking about using just one servo for the flaps, but I don't have much experience in running push/pull cables and the like. You know of anywhere with some nice pics and a build log of how to do flaps off one servo?

[Dillzio]

I just went to the hobby shop in the city to buy a new super cub wing. The rest of the stuff is on the way from hobbyzone, but they couldn't send the wing because it was too big. I had a good long chat with the guy in the shop about carbon rod reinforcement options, and how to run my flaps off just one servo. Running the flaps off one servo, while certainly possible, and practical, is a somewhat complicated matter, and you end up with linkages and stuff coming out of your fuselage so it's just not as neat. We both agreed that just using two separate servos is a much tidier, and easier option.

With regard to the carbon spar, he ended up talking me into using three thin spars instead of just one. The spars are only about 3/4mm by 2.5mm and 1m long, and while they're thin and floppy one way, they're really strong when you try to bend them along their vertical, they just need some bracing to keep them from twisting. The guy in the shop told me that then can easily be installed by just putting a long cut in the foam, and sliding the spar down into the cut, no need to cut out a channel or remove any foam, just a single cut will do, and once the spar is sandwiched between the foam for some lateral support it should make it rock hard.

I'm planning on two spars in the top of the wing, as far forward and back as I can, and one on the bottom of the wing, roughly in the middle but it has to clear the servos too. I also got my red flashing bike light today, it turns out to be REALLY easy to strip away the casing, so you're just left with 5 LEDs on a tiny circuit board :-)

It's slowly all coming together...

[Dillzio]

BUMP!

So, is anyone able to recommend a relatively neat and easy single servo flaps setup, or is one servo per flap pretty much the way to go?

Also, do any of you chaps have experience with using the thin carbon spars, instead of the rod?

[Legot]

I used one thing spar, 7mm by 2mm or so, slotted verticaly on the CG. The spar itself only bends back and forwards,(not relivent) but can not bend up and down.

I'm working on my flaps with some single servo setup. lat time it was wire controlled, this time it will either be cable or wire or rope if I find a way.

[Dillzio]

The guy in the model shop recommended that I use a torque rod to run the flaps off one servo, you have a metal rod that is twisted/rotated by a servo, and at the ends of the rod, next to the flaps, you have control horns that move forwards and backwards as the rod is turned. The other way to do it is to have bell-horns (the L-shaped ones) by the flaps, and have them linked to a servo in the centre of the wing by pushrods. As the servo causes left and right movement on the pushrod that runs along the wing to the bell-horns, the bell horns change the movement around 90 degrees to push the flaps up and down.

I think the torque rod way would be the best if you could do it really well.

I'm adding the carbon spars and de-dihedraling the wing tonight, I've come up with a brilliant way of doing it, I'll post videos of how I did it. I'm making a video build log :-D

[badlands]

I have flaperons but never use them - didnt make much of a difference & a bit pointless IMHO.

[Dillzio]

Yes, BTW, thanks to all that gave me feedback on the flaperons. If it weren't for your advice I would have gone with them, only to ultimately be disappointed. Also, cheers to Erwin for convincing me to grab a couple of spare servos, this will enable me to install flaps now :-)

Removing the dihedral proved to be more difficult than I though, but in the end my thin carbon spars provided the solution for me. At first I tried to remove the dihedral with packing tape, to hold it in position while the glue dried, but this ended up making the bottom of the wings curved. You really need the pressure to flatten out the wing to be applied close to the centre to eliminate the 'bowing' effect. I achieved this with 1.25KG weights, I tried .5KG but it wasn't enough.

My 'brilliant' idea turned out that it wouldn't have worked, well it would have worked OK, but it wouldn't reduce the dihedral enough. That idea was to sticky tape three paddlepop sticks to the underside of each side of the wing where the wing strut holes were, then by adding weights to flatten it out the popsicle sticks could act as spacers to hold the wing in the position for the epoxy to dry. The problem with that seemed to be that after the weights were removed, the wing would spring back to some extent.

It turned out to be much easier once I got the carbon spars in. As I mentioned, they're less than 1mm thick so they can just slot down into a cut, so they sandwich into the foam really tightly. Once I had two carbon spars in the wing, I could bend the wing as flat as I wanted, or even bend it the other way, and it would stay there. As you bend the wing, you can hear the rods shifting as they bing to the foam and slip a little bit at a time. Whenever you bend it, it springs back it bit, so you just bend it more than you need to and it will spring back to where you want it. The only tricky bit is getting both sides even, as more than likely once you put the wing on a flat surface, you'll see that one wing tip is higher than the other.

Basically, it then became a process of coating the carbon in some slow setting epoxy using butchers/baking paper, pushing it down into the slots, then bending the wing into the right shape. Once the rods are in position, and are holding the wing in about the right position, I put some .5kg weights either side of the middle, to encorage the end to bend in the right place, and now bow. I also put 4 popsicle sticks under each wingtip to remove the bow in the bottom of the wing. 8 hours later and it turns out I can still make find adjustments to it, I just saw one side ended up a bit higher than the other, so I put a .5kg weight one side, two .5 kg weights the other side, and it evened things out.

After a bit more tweaking, and I got it all just right, I ran along the CF channels with some super (CA) glue, the thin runny fast setting stuff. I've now got each wing tip 12mm above the surface.

[john66]

May 3, 2010 5:35:46 GMT 1 Dillzio said:

I've now got each wing tip 12mm above the surface.

S'cuse my ignorance, why the 12mm on the wing tips? I presume that means leaving some dehidral, if so why?

I liked the look of the way Ellis removes his with the cuts tape n glue filler/sealer..... supercubclub.proboards.com/index.cgi?board=sccgeneral&action=display&thread=1758 4th post down by Ellis.

Im guessing Ellis's method leaves no dehidral. I understand that lack cof dehidral will not affect climb, only stability and the planes ease of righting itself. I was also under the impression that dehidral and ailerons were a no no from reading other threads?

Any light anyone can shed would be great

Yours confused, John

[flydiver]

Rudders need dihedral to work well for scale type plane (it's different on 3D types). Rudder alone on a flat wing is mostly awkward to awful. It certainly is on the Cub. New fliers that get part of the info and flatten the wing but don't put ailerons in expecting the rudder to work are going to get a rude surprise.

Flat wings want ailerons. A little dihedral will not detract too much. A lot of war birds have a little dihedral still to put some stability back into a low wing.
Full dihedral may negate some of the aileron authority. It'll work, but not as well, but the rudder will still work.

Dillzio want's 'training wheels', with flaps, flapperons, ailerons, crow, buzzard, lisp, limp, and tassels.
(maybe fuzzy dice, and chrome wheels too--- ;D)

If he doesn't get some plane parts soon he's going to carve one out of soap.

[Dillzio]

LMAO, you called it Fly! You know me suprisingly well. Luckily, I have really slow setting epoxy to put the carbon spars in my wing with so that's keeping my occupied for a while. The only frustrating things is I need to know how long my stryker pushrods will be, so I know where to put my servos, so I know where to put the carbon spar on the bottom of the wing.

I'm now going flaps instead of flapperons, and while I don't plan to use tassels, I am considering towing a ping pong ball with a super bright led inside it behind my plane.

I'm leaving a little dihedral so that the plane will still like to stay the right way up all on it's own, and so it will still fly like a cub if I use rudder. If I'm going to use it for night flying I'll need it to still have some stability. I've got my dihedral down to 10-11mm now, it looks really good. I think the two carbon spars in the top of the wing may not have been glued in ideally, it took a lot of shifting and adjusting to get the angle right so I doubt the glue to to set ideally.

Now that it's in shape, I'm thinking about putting another spar in the top, using lots of epoxy and leaving it to set properly. I was planning on using my third spar for under the wing, to offer it some strength to prevent the wings from bending down, but I'm not sure. - it seems to me that I only really need supports on the top, not the bottom, any thoughts?

Oh, one more thing about the ailerons, I'm making them in metric (45mmx400mm), should make the plane much more efficient, using more modern technology and all that sort of thing :-)
It will also be balanced with the proper centre of gravity (not the center of gravity) for better aerobatic maneuverability (CRAP, I just remembered, I always set my CG to 2&3/8 of an inch, I'd better check what that is in mm).

Edit:
Actually, I think I will put another spar in the top of the wing, bed it in perfectly with plenty of epoxy and give it a good while to set. I believe it was fly that once said "struts? I don't want no stinkin' struts!". I guess now I can join the club :-)

So far, with the two struts in the top, it stops the wing from bending up, but not so much down. Another firmly bedded spar in the top and nothing will be bending that wing upwards, struts will be a thing of the past ;D

[vroom]

The easiest way to make a Cub wing flat is to tape the center of the wing down to your work surface and make 2 slits in the top of the wing along the creases where the dihedral starts. Slice through 95% of the wing and just leave the very bottom surface uncut. The wing will lay down nice and flat on its own as you make your cuts.

Tape the wing tips down so the wing is laying flat across your work surface. Fill the gaps in the top side of the wing with Gorilla Glue and some spare pieces of Depron or other foam. Just monitor the expansion of the glue till its dried. Dremil it smooth and you have a solid wing that is as straight as you could ever want.

[Dillzio]

ah crap, I just realised, I might not have a spare channel for my nav lights :-( I'm getting a 6-ch radio, that's throttle, elevator, rudder, two channels for ailerons and flaps, that's 6. If I want my receiver controlled switch, I'll have to either put both ailerons on a single channel and sacrifice my computer differential and individual sub trim for each servo, or I can give up on my flaps.

What do you think would be the best to go without, the receiver controlled switch, the flaps, or individual channels for each aileron? Any input appreciated, cheers.

[ginginho]

May 3, 2010 21:37:42 GMT 1 flydiver said:

[Snipped]
Dillzio want's 'training wheels', with flaps, flapperons, ailerons, crow, buzzard, lisp, limp, and tassels.
(maybe fuzzy dice, and chrome wheels too--- ;D)

If he doesn't get some plane parts soon he's going to carve one out of soap.

Tee-hee at that Fly. I'm wondering that if Dillz makes it ever-so pretty that he might get start getting the guys who hangout where he lost he previous SC interested in him again! ;D

If he's going to make one out of soap, he'd better not drop it when they are around. I've heard things about that when jailbirds drop theirs in the showers!

Oh and Dillz, if the motor you have is half as good as the 35-36 I put in my Gemini, you be a very happy bunny.