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Old May 03, 2009, 09:24 PM
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I think tomorrow I'll go to the LHS and see what their strongest micro is. I'll try that first. In any case, even if it doesn't work perfectly, I'm sure it will work better than the DS-929MG.

I don't think the weather will cooperate until Wednesday though
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Old May 04, 2009, 06:34 AM
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I used a Futaba S3003 and it works fine. Are you sure the servo arm wire link isn't catching?
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Old May 04, 2009, 09:36 AM
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electriceye, that Futaba has tons of torque! 44/57oz 5/6v. The Corona 929MG only has 30oz @6v. The build is fine, this appears to be a wing loading issue while in the air. Do you have any photos of how you fit the full-size servo?

What is your AUW and can you open/close at speed?
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Old May 04, 2009, 10:16 AM
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As stated earlier ...
Mike designed this bird to be built Light ! Mine is ~ 12 oz
Those wings have to be slippery on the INSIDE !
There are comments in this thread regarding plastic "bearings" around the wing boss's
plus the use of Slippery tapes between the wings and the matching fuse parts.

I have mentioned some of the very slippery UHMW tape used on Table Saw Fences.
It's a self sticking plastic film ( akin to slipper milk bottle plastic).

When you add up the frustration, shipping costs and unknowns
it's almost not worth the effort to use a cheaper UH servo as opposed to
a nice reliable HS85mg .

FWIW

CU L8r , Bob
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Old May 04, 2009, 10:43 AM
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Yeah, I know the 20oz AUW isn't recommended but here in Nebraska I need the weight if I want to fly. We seldom have calm days and most days get 12mph winds on average. My lighter planes get thrown around a lot. I've found that 19-20oz is ideal.

I'm going to put in an HS85MG and will look into the UHMW.

The HS85MG may not let me open/close like normal but I'm sure it will work better than the Corona 929MG.
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Old May 04, 2009, 12:39 PM
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wing loading

All of mine 6 but one has been in the 19 to 24 oz weight with very hot motors and 2100 3 cells and 2200 4 cell packs..i have found that building these in the 20 oz range. and useing the good servos ie HS85mg ..even putting the plastic on the wing bosses as BirdOfPlay has said and i use the very very slick UHMW tape . you can find at lowis or home depo..with the design of the pivot area, you will still have to unload the wing a bit with a touch of down elev for the wings to sweep forward in high speed flight..i have also found that you need a very small amount up & down play at the wing root. just what works for me...

check out
http://www.rcgroups.com/forums/showt...0#post10937366
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Old May 04, 2009, 12:44 PM
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I bought a Futaba S3102 MG at the LHS which has 57 oz of torque at 6v!

I went to Lowes but they don't have the UHMW. I called Home Depot and they don't either. One Menards said they carry it but are out of stock. I'm going to call the other.
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Old May 04, 2009, 03:03 PM
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Quote:
Originally Posted by sgf323
electriceye, that Futaba has tons of torque! 44/57oz 5/6v. The Corona 929MG only has 30oz @6v. The build is fine, this appears to be a wing loading issue while in the air. Do you have any photos of how you fit the full-size servo?

What is your AUW and can you open/close at speed?
I can't remeber of hand but Ithink AUW is around the 20oz to 21oz
I just fitted as per plans. I just made sure everything moved before finally gluing the top on permanently-To access any of the wing sweep gear I would have to cut the model and I don't really want to do that, and I would hope I wouldn't need access, unless something drastic happens!
By luck, more than judgement, the depth of the servo was right just fitting it as per the plans/build guide (I think as it was a while ago I built it, but I can't remember any problems). If you look side on at the swing pivot whilst lying a flat object like a rule across the pivot point and the fuselage you can move the wings to see if everything is clear. Then try with the top plate. You could tape and/or pin the top plate just to make sure the wing swing works fine before gluing. And I'm sure this is obvious, but I'd be really careful how much glue you use on the pivot points and surrounding areas when you do finally glue the swing cover top plate on using an adhesive that does swell or foam up. Shims on pivot points is the other thing? How tight a fit are the wings over the pivot points? I have quite a lot, about 0.4mm with thin plastic shims fitted until I was happy with the compromise between easy movement and sloppiness.You can also 'adjust the pivot spacers, using a thicker or thinner material disc until ,again you have the compromise between easy opening without too much slop. I have a fair amount of slop at the wing tips but I think this is inevitable, and it flies fine with wings out and when the wings were required to swing. It was definately an 'Oh Wow!!' moment when I saw the wings changing position in flight
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Old May 04, 2009, 03:18 PM
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Hey Randy ! ya Back for a while now :-) ?

6 of them ?!?! geez you must be supplying the Whole Club !

sgf : Yeah I remember those "Plains Winds" when I was in Wichita 14 mpg Avg
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Old May 04, 2009, 03:36 PM
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Mine moves very freely with the top deck glued down. I used CA so no foaming going on. The wings moved very well with the Corona's on the ground. I even got the smacking sound as they closed against the rear foam pieces. The issue definitely is from wing loading since it works perfectly fine (and fast) in the air when I do a maneuver to remove the load from the wings. It really wasn't a speed issue either. I could do a full speed loop and at the top I could open/close the wings.

I've got the Futaba S3102 servo in and with the 57oz I shouldn't have any issues based on your S3003 working. Still, I'm heading to Westlake's to get some UHMW tape. I'm going to do all I can to reduce friction so hopefully it will have no problem operating in the air.
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Old May 04, 2009, 05:05 PM
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still at work

BirdOfPlay
i'm still over here in Saudi intill the 15th..think i will spend my time home this time to finish my CNC. getting tired cutting things out by hand..LOL..I have a lot more done on it than the pictures show.the pictures are a month old..ready for the steppers and getting it all dialed in..spending my spare time over here converting my stuff to g code to be ready..my stepper package should be waitting on me when i get home..all ready got the plans for the next one..the Joe's 4 x 4..this one was a great learning tool..and another habit to pick up..but my wife thinks it's cool. so that helps

sgf323.. going to be very hard to do a refit with the tape if you are flying it now..you did make poster board templates of all the parts before you assembled the bird..Right??..so you could cut out another one.LOL. for the tape to help it needs to be top and bottom on the wing and under the top plate..in everyone of the one's i have done. you had to unload the wing to get a good forward sweep in flight..but still way too cool in flight..the 58" wing span one is freaky cool, it wows everyone everytime i fly it. big as it is a gentle hand toss and she is off..
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Old May 04, 2009, 06:09 PM
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Are you kidding? Of course I didn't take time to trace anything! I figure if I need to I'll have kinkos print me up the PDF.

I had no problems opening up the top though. I just used a thin metal ruler to break the glue joints by sliding it between the wing and the deck. I also used wood spacers which made it easier.

I'm putting poly tape on top and bottom decks as well as on the top and bottom of the wings.

If it can't open and close without unloading I'll be ok with it, I just want to do everything I can along with going to the stronger servo.
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Old May 04, 2009, 06:25 PM
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tape

sounds like you have it well under control..one other thing i do is i always run a external BEC .. even thro it's a small plane, the reason is i can program it to suppy 6 volts to the servos..most speed controls only supply around 4.8..you can almost double your servos torque..like on the HS85MG that i love in this bird.. that 7 oz makes a world of diff..my 2 cents anyway

4.8 volts is 42 oz of torque
6.0 volts is 49 oz of torque

On the pdf file my local Kinkos has a large format printer that will print right on heavy posterboard..really nice saves spray glueing the print and sticking it on your self.. they charge like $ 2.25 more to print on posterboard to me it's worth it..
but in a month with my CNC finished, just load the foam and hit start..LOL..going to love it..

enjoy the bird, like others in here you will be building a lot more and souping them up..so far the fastest has been the one with the JustGoFly 450TH...4.5 X 4.5 prop and 2400 4 cell pack..got to fly to beleave..so fast and at the same time goes so slow in high Alfa with a nice breeze..i try to keep mine in the 19 to 22 oz range works for me..
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Old May 04, 2009, 06:42 PM
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Yeah, I bought several HXT UBEC's from HC last year and finally have a reason to use one! I put it in and ended up burning up one of my Corona DS929MG's because I left the switch in the open position and it only opened mid-way. I kept it like that for the whole flight and when it got down it was dead.

I replaced it from the bottom with another 929 which worked well after I learned the unloading tip.

Next time I go out it will be with the 57oz S3102 and the poly tape so hopefully it's at least a little easier! Less friction and nearly twice the torque has got to get me somewhere!
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Old May 04, 2009, 07:49 PM
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Looking good Randy !

My original Shopbot was on a wooden table.
I eventually went to a metal Fab shop and simply had them cut for me.
Then I converted teh Cable drive to Rack and Pinion and , well ...
So far so good :-)))

If I wanted stronger capability I could upgrade the Steppers.
I have some BIG Nema34's but since I mostly do Foam now, it hardly seems worth it.
Especially when Speeds and Feeds for foam are in my current capability.
I'm already way over kill for foam with a 3.25Hp router.

Practice a bunch with CAD, Conversions and on screen simulations.
Then just go for it :-)


-----


Oh and IF I hadnt bent TWO (2ea) 5mm shafts already on another bigbird
I might consider getting my BIG F-14 out of the closet and finishing it.

Sorry if I already asked but,
Whats your AUW on that BigBoy ?
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