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Old May 10, 2012, 08:05 AM
Registered User
Amsterdam
Joined Sep 2005
143 Posts
im planting the wing-tip-twist-mechanism inside the wings..

first i wanted to put the servo's inside the tips, and attach the servoarm to the fixed wingspar, so the servo's body would twist the wings.. But the tips were too thin so i decided to turn that around. But it was kinda tricky to make such a long servo arm rigid enought to trasport that rotating force to the tips, yet still very light and small... again, TEFLON tape came to the rescue!


I could mount a 2 mm carbon rod on top af a servo arm, and secure it with superglue and TEFLON tape:



Then I used a dremel to make a small groove in the end. did the same with a shorter piece, so they would interlock at an angle. fixed them with a hair-sized metal wire (from a electricity cable) and superglue, and sealed it with TEFLON tape. fixed like a rock!




..I'm particulary proud of the fact that i made both spars just on the eye, without measuring anything, and they came out EXACTLY the same...



and Im loving TEFLON tape. it doesn't weigh anything, it expremely thin, its not sticky except to itself, it doesnt react with anything, it insulates electricity and can resist high temperatures, and its extremely strong..

anyway, this is how I hope to make the wings twist..:



I only attached the rod to the wing at the end, the long part can rotate freely inside -again- a drinking straw.

..BUT I'm a bit worried that the servo's won't have enough torque for the job...
actually i was thinking about some gear reduction for the servo. the wings dont have to twist 30 or anything, just 10 on both sides would be enough to make the bird roll i guess.

maybe some micro planetry 3:1 reduction gearbox on the servo's head would be good,
something like this:


http://www.micromark.com/motorized-p...rbox,8179.html

..does anyone know where i could get something like that for servo's..?
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Old May 10, 2012, 10:10 AM
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CoolerByTheLake's Avatar
United States, MN, Hermantown
Joined Dec 2008
5,628 Posts
I would say to just get stronger servos. That would be the simpliest to do, minimal weight penalty, and less to go wrong. Have you tried out these servos yet?
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Old May 10, 2012, 10:19 AM
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hanzie's Avatar
Nederland, GE, Wageningen
Joined Nov 2011
288 Posts
Whoa! Moving tail/wings, silent edf, bird shape... It'll be just like a real bird from a distance! Now if only you could make it fly by flapping its wings, it would be perfect!

Where do you plan on flying it? You should go to the shore and annoy some real seaguls, just to see how they react. A friend of mine once did that with a 'Killer Hai' and it ended up in a real dogfight between one plane and more than six birds that were trying to bring it down, feathers everywhere! If you attach a camera to it, it'll be like a real birds eye view.

Doesn't that Hema glue add a lot of weight? If not, I now have a new technique when building foamies.
Keep building,
Hanzie
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Old May 10, 2012, 11:45 AM
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Amsterdam
Joined Sep 2005
143 Posts
I havent tried the servo's yet, still waiting for for some connectors to be able to connect them to the MIG's reciever.. but stronger servo's is a last resort, I allready bought these because they were stronger than the MIG's stock servos. and I wouldn't mind if they made a smaller movement, with more force..!

and I didn't measure it, but the hema glue doesnt seem to add a lot of weight! when you apply a really thick layer, it dries up like a thin hard skin. that means most of the volume of the glue is just water. so when deluded with water and applied in a thin layer, it dries up invisibly... but you can FEEL the difference..! go ahead and try!
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Old May 13, 2012, 06:30 AM
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Amsterdam
Joined Sep 2005
143 Posts
OK, I need help..!

couldn't wait anymore for the right connector cables, so i just stripped the wires, attached the connectors from the old stock servo's and I've connected all the electronics for testing.

at first it all seemed to work fine! but this coded-beeping ESC was still a mystery for me (didn't have or know about a manual..) and after a first flawless run, now the motor has stopped responding. the sevo's still work though..! I've found the manual, which is supposed to also work for the HK 18-20A ESC I got.

..But my ESC doesn't do what the manual sais it should do. it just gives those "1,2,3" beeps that mean "voltage OK", and then silence.. anyone know what to do?

My last hope is fully charging the thunderpower 3S LIPO I got, but (again..) it appears to hava a different charging connector then the stock 2s LIPO from the MIG.. (the charger is a 2s/3s charger..)

And finally, the wing-twisting servo is doing it's job, and twisting the wings...a inimini tiny bit! it seemes to have enought torque to fully rotate the spar, but the wing is too rigid to allow enough twisting. So I'm thinking about ways to make the wing more 'twist-sensitive'...

I think I'm gonna cut out a big compartment, and leave some ribs in the direction of where feathers should be, and then cover it again with 2 mm depron which i won't glue stuck completely, in such a way that it will be able to 'twist & slide' a bit.. but well see. for now im still too reluctant to cut up those beautiful wings..

first the ESC problem. to clarify all this text, a VIDEO:
Seagull TEST; Electr Speed controller + wing twisting servo. (2 min 1 sec)


..any advice would be much appreciated!!
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Old May 14, 2012, 09:37 AM
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bobbyhigh's Avatar
Singapore, Singapore
Joined Oct 2011
31 Posts
Johannez,

May i offer the following tips:

1. ESC programming -
a) If you have another RX, re-bind with the transmitter before connecting the ESC. It somehow worked for me.
b) Otherwise, try power up the transmitter with throttle up. Power up the rx & ESC. Wait about 10s, bring throttle stick down, wait anther 10s, bring throttle stick up again. If the ESC responds, then you are in luck!

2. Thunderpower connector -
If you get your ESC from HK, then purchase this connector converter for charging your TP lipo. http://www.hobbyking.com/hobbyking/s...idProduct=9733 (Male JST-XH <-> Female Thunderpower 3S 5cm (5pcs/bag))

3. "Twisty" Wing -
You may have to sand down the trailing edge of the wing near the wing tip to reduce the rigidity of the wing. The other option is to use a larger servo for more torque.

Cheers

Quote:
Originally Posted by Johannez View Post
OK, I need help..!

couldn't wait anymore for the right connector cables, so i just stripped the wires, attached the connectors from the old stock servo's and I've connected all the electronics for testing.

at first it all seemed to work fine! but this coded-beeping ESC was still a mystery for me (didn't have or know about a manual..) and after a first flawless run, now the motor has stopped responding. the sevo's still work though..! I've found the manual, which is supposed to also work for the HK 18-20A ESC I got.

..But my ESC doesn't do what the manual sais it should do. it just gives those "1,2,3" beeps that mean "voltage OK", and then silence.. anyone know what to do?

My last hope is fully charging the thunderpower 3S LIPO I got, but (again..) it appears to hava a different charging connector then the stock 2s LIPO from the MIG.. (the charger is a 2s/3s charger..)

And finally, the wing-twisting servo is doing it's job, and twisting the wings...a inimini tiny bit! it seemes to have enought torque to fully rotate the spar, but the wing is too rigid to allow enough twisting. So I'm thinking about ways to make the wing more 'twist-sensitive'...

I think I'm gonna cut out a big compartment, and leave some ribs in the direction of where feathers should be, and then cover it again with 2 mm depron which i won't glue stuck completely, in such a way that it will be able to 'twist & slide' a bit.. but well see. for now im still too reluctant to cut up those beautiful wings..

first the ESC problem. to clarify all this text, a VIDEO:
http://www.youtube.com/watch?v=Julj_...ature=youtu.be

..any advice would be much appreciated!!
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Old May 14, 2012, 04:50 PM
Registered User
Amsterdam
Joined Sep 2005
143 Posts
Bobbyhigh, thank you for your elaborate advice! I wish more people would be thinking along like you..!

I've tried your tips on the esc, but ...with no luck.

1; -I have two other 2.4 ghz transmitters, one from the kyosho minium series, and one from the nine eagles sky runner. there's a reset-binding button on the MIG's tiny reciever, (well, thats what i assume it is) but it doesnt seem to bind with any of those other transmitters.. (is there a special way to bind 2.4 ghz systems..?)

-also the 10 second wait -sequence had no effect..

I could maby buy a programming card for that esc, or just hope that fully recharging the lipo will work... which bring us to point 2;

2; -I've found those JST -> TP 3s connectors, on ebay in germany, it's on its way! THANKS!

3; The wings. before I even starting doing something, I'm always building ahead in my head, and then testflying it. when i considered the sanding option, what happened was this; the wings are coated. so i had to remove all the coating and then sand it a lot, and still keep an eye on profile and symmetry, which was a lot of difficult work. then in order to make them twistable enough, the wings became so flimsy, they lost all rigidity and thus became more unstable. AND very vulnerable.. the tips broke off at the first unhappy landing. SO instead i took (indeed) a stronger servo, aswel as a stronger spar. this worked, but it was expensive (2 new servos) and heavy (+two new bulkier spars) and drawing a lot more current from my battery... Ideally I had to find a way to make those wings twistable, without losing rigidity over the other two axis, and without losing profile or gaining weight...

so now im thinking about removing some sections (in white on the attached photo), and to cover the wing with a two 2mm-thin sheets of depron, top and bottom, leaving those ribs (for support of the spar and profile-rigidity) to move freely inside the chamber, allowing the wing to twist!

..Im just still seeing those wing-tips break of at the first unhappy landing... (but it will look nice against the SUN!
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Old May 15, 2012, 11:37 AM
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bobbyhigh's Avatar
Singapore, Singapore
Joined Oct 2011
31 Posts
Just to confirm it is not my English...

1. I'm not saying that you bind the Rx on the MIG (Seagull) to the other Tx but rather, take the ESC and connect it to another set of Tx/Rx pair. As 2.4Ghz systems are implemented differently, you just can't bind a Skyangel Rx with Kyosho minium nor Nine Eagles system. Try using another Skyangel Rx or borrow a Tx & Rx from a fellow hobbyist to reinitialise your ESC. Based on your description, the ESC probably "stuck" in a Program Mode rather than a lipo LVC.

3. Removing sections of the wing is a neat idea, however reinforcing with depron may not be ideal as it is still fragile. Perhaps Blenderm tape may help? It's tough, flexible, translucent and will certainly survive a crash! :-)

Cheers
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Last edited by bobbyhigh; May 15, 2012 at 11:44 AM.
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Old May 15, 2012, 03:46 PM
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Amsterdam
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"Blenderm tape"..? I've never heard of it before..! sounds very interesting! I've looked it up and it seems pretty handy.. is it light as well? and how flexible? well, I'll just get my hand on it somehow, and see. Thank you again!

the 2mm depron wasnt intended as reinforcement though, but simply as a mildly flexible cover. coating it with hobbyglue was going to make it a bit more impact-resistant.
today, while walking outside, i thought; when (and IF) i cut those sections out, i might just reinforce that thin part on the leading edge by superglue-ing some corbon fibers from a crushed carbon rod to it, that should make it quite strong again, while keeping the gained flexiblillity.. right?

and about the ESC, indeed I misunderstood. I'd try but I dont have any other friends with gear like this.. in fact, most of my friends don't even have a clue I do this stuff..! and most of the time, I dont. but now I'm immersed, addicted and hopelessly lost in this project.. I'll just pay a visit to the RC modelshop some day, and try your advice.

more GOOD news: postman came, delibered the EAGLE A3 flight controller!

I hooked all it up and it works like a breeze..! (well, at least inside my livingroom it does)
check it out:


EAGLE A3 flight controller -test on model seagull (3 min 18 sec)
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Old May 16, 2012, 10:41 AM
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Singapore, Singapore
Joined Oct 2011
31 Posts
Blenderm tape is like scotch tape but stretchable. If you need a stronger covering material, carbon fiber cloth may be the answer instead of using crushed CF rod & glue. In any case you probably get more kick out of trying new ideas. Keep those creative juices flowing! :-)

The eagle A3 is certainly an interesting device. Hopefully we'll get to see the gull in flight soon!
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Old May 16, 2012, 11:07 AM
Fear me, I'm a space-duck.
hanzie's Avatar
Nederland, GE, Wageningen
Joined Nov 2011
288 Posts
If your servos work, you do have connection with the transmitter. Since the esc does startup, but does not arm, it could be your throttle trim is causing trouble. Try trim it down completely. If that doesn't work, check if the fase wire (The white one) is properly soldered to the esc board. I once had the same problem with a HK esc and after I removed the cover (The shrinktube) I found the fase wire hanging loose. That way the esc does power the receiver and servos, but doesn't get any signal back so it ussumes there is no connection with the transmitter, Which causes it not to arm. Maybe that helps?
Hanzie
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Old May 18, 2012, 01:41 AM
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Amsterdam
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well, crushing carbon rods produced just that; crushed corbon rods.. so getting my hands on some carbon fibers seemd like a better idea indeed.

I ordered some carbon thread, and then came across this stuff


..it weighs only 40 gr/m2, so covering my complete leading edge would add only around 0.8 gram and make it virtually BULLETPROOF..!
(just too bad i discovered afterwards you need a pair of $100,-scissors just to be able to cut it.. well, we'll just see what magical present santa drops in my mailbox this time

@ hanzie, thank you! i tried the trimming thing allready, and the white wire seems to be attached fine. but i'll take it to the shop soon, and hook it up to a programming card. see if that helps.
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Old May 18, 2012, 10:48 AM
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Singapore, Singapore
Joined Oct 2011
31 Posts
A suggestion is to get yourself a new ESC instead of wasting time or a trip to the local hobby shop (if it is far away). It'll probably cost just a fraction of your time & effort (trying to find a prog card for it). Tempting it may be, perhaps You may want to get the bird airborne first before investing more $$$, time & effort perfecting the build? :-)

Bob
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Old May 18, 2012, 04:12 PM
"Take Off" eh!
vettster's Avatar
Canada, ON, Beeton
Joined Aug 2008
3,171 Posts
Your ESC is not arming because it thinks the throttle is up. Its called fail safe and prevents the motor from turning accidently when the battery is plugged in.

Set your Throttle and Trim to ZERO then bind your Rx. Remove the bind plug BEFORE you unplug the battery, and you should be good to go. If your throttle or trim is even the slightest bit advanced..the ESC will not arm when you plug in the battery.

Give it a go.
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Old May 19, 2012, 02:38 AM
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Amsterdam
Joined Sep 2005
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Wingerons!!
Multiplex Fox glider power conversion wingeron & a P-51 crash in the background (4 min 5 sec)

..why didn't i think of that before? might be a bit less innovative but it's much easier construction and there's no need to cut up my wings..!

anayway, thanks for the advice on the ESC! I dont have a 'Bind plug'. it's easy to fix as i understand it, but i wouldn't know in which of the 4 channels on the reciever to plug it into.. or is the ESC itself also the 'bind plug'..?
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