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Old May 21, 2009, 07:57 PM
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birdofplay's Avatar
United States, IN, Indianapolis
Joined Dec 2005
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Ok that got me thinking again - usually that means big trouble :-)

So here is the animation of my latest idea for wing movement.

The Center or RACK gear would be made out of hard plastic. ( GREEN )
I have some 1/4 Sintra - a foamed PVC sheet - although it could be wood too.

The wings would have the "Gears" on the inside end. ( RED )
The other part that would need to be changed would be that center fuse sheet
just behind the wings.
A single servo would move the Rack !

Just click on the image and it "Should" run an animation 4 times.
It's one of those gif animation thangs.
Sorry for poor quality but I havent used it in a long time.

Design considerations were to make BOTH WINGS identical.
"Guide Pins" may be necessary to keep the Rack centered - not a big deal.

I'm not sure IF I can fit them onto the current "CNC Layout".

IF there is any interest I will try.
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Last edited by birdofplay; May 21, 2009 at 08:23 PM.
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Old May 21, 2009, 08:28 PM
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birdofplay's Avatar
United States, IN, Indianapolis
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OOOPS !!!

The Rack has to move 2.8" from Open to Closed !

Dang thats too much to ask from a servo

Oh well ...

Back to the think tank :-(

OK OK OK

How about putting a Wing Servo at EACH WING PIVOT POINT
and gluing the Wing TO THE Servo ARM !

The servos would be hidden IN the Nacels

The ONLY PART change would be the Wings !
They would only have to have a SMALL hole and slot for the servo arm
as opposed to the Big Boss hole !
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Old May 21, 2009, 09:15 PM
Row 0, Seat A
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Savannah, GA
Joined Jan 2008
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Quote:
Originally Posted by birdofplay
OOOPS !!!

The Rack has to move 2.8" from Open to Closed !

Dang thats too much to ask from a servo

Oh well ...

Back to the think tank :-(

OK OK OK

How about putting a Wing Servo at EACH WING PIVOT POINT
and gluing the Wing TO THE Servo ARM !

The servos would be hidden IN the Nacels

The ONLY PART change would be the Wings !
They would only have to have a SMALL hole and slot for the servo arm
as opposed to the Big Boss hole !
BOP,

I've got to bump this thread just to get that gawdawful GIF out of view!!

I'm going to be having nightmares tonight of a wing flapping gruesome red and green gif gremlin chasing me through some bat cave or something.

On a more positive note, I got all of the depron parts for my F-14 cut out today. Wow, that's a lot of parts! Your price for a pizza box kit is a good deal.

I think the large pivot bearing of this design is probably the best way to go for this size model. You just have to concede that you're going to have to use a big honking servo to move the wings reliably, especially with any g on the plane. To quote Ed Heineman, the famous Douglas designer, "you must design in simplicity and add lightness" (as best that I recall).

KISS + big motor = fun airplane

Ted
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Old May 21, 2009, 09:35 PM
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United States, LA, Blanchard
Joined Jan 2006
790 Posts
rack system

Good idea there BirdOfPlay..you know to get the 2.8 " of travel there are many small hi torque boat winch servos on the market that wound fit. they turn 2 or 3 times would have to have like a long arm and use the end points in the radio to program the servo to only move in a certin range. or a small retract servo .. seems hobby lobby has some flat push / pull servos..

http://www.advantagehobby.com/produc...cat=321&page=1

or chain drive..LOL

http://www.servocity.com/html/servo_...s___chain.html

and for the heavy duty power

http://www.servocity.com/html/heavy_...vo__25__l.html


sorry could'nt help myself Bird.. the dual servos sound like the plan...

Randy
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Old May 21, 2009, 10:50 PM
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Yep I figure that a couple of HS755MG's on your ( our ) 150% sized F-14's
would swing the wings good enough so we wouldnt even NEED the motor ! :-)

Sorry 'bout that gif !

you can STOP it by hitting esc , at least it works for me using Firefox !
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Old May 21, 2009, 11:31 PM
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United States, LA, Blanchard
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wing sweep

You know we really don't need to redesign anything.. even on the 150% bird one servo works just fine..i have never had any problum once i set it up right.. but hey ,, our hobby is all about trying new things.. myself i will stick with has worked fine for me..getting ready to cut out 150% #2 this one will be heavly modded. hotwired foam wing cores.airfoil.sheeted w/ailerons.full fuse...retracts...will spend sometime on this one .. will be going with a e-flite power 90 on this one.fins will be 4 inches farther apart so i can run a larger prop.
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Old May 22, 2009, 12:52 AM
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Wouldn't it work relatively easily to have one servo in the current location, maybe a bit further back, then a second directly in front of it facing the opposite direction? It could be setup to basically operate similar to how the one large horn pulls the wing wires to opposite sides and you could then easily adjust wing positions, which for me was the biggest headache.

Even without any wing modding though, this plane flies incredibly well with a good servo once you get it setup and the rudder is something that I think everyone should do!
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Old May 22, 2009, 06:35 PM
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Quote:
Originally Posted by sgf323
I wouldn't bother with doing that. Poly tape and a strong S3102 servo works extremely well for me. I think the ease of doing it that way outways the added problems with trying to figure out a rubberband solution let alone the additional stress there would be on the servo.
I wouldn't be trying it if I had the larger servo. Pretty new to the hobby and all I have are the cheapy HXT900 servos from hobby city (about a dozen), but I guess I can just hook one to each wing instead of the rubber band idea (or pen spring...).
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Old May 22, 2009, 10:23 PM
INDORUS EXPARAMINTO
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Springfield, Missouri, United States
Joined Jul 2002
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OK Brothers,
If you had your pick of motors, which one would you use.
An Axi 2212/20 or a Komodo 2208/8

Larry
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Old May 23, 2009, 12:07 AM
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Mine is built Light and uses the Komodo 257 ( ~ 12 oz )

I dunno about the motors you mentioned.
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Old May 23, 2009, 12:43 AM
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I had my battery door open up today while doing a super fast roll with the wings swept! Luckily the piece of wood I have on the front of the door is tight enough with the front of the battery that it didn't come off and the battery didn't fall out.

On my first landing attempt I dropped throttle as usual but the door was acting like a brake and I almost went in to some trees! I recovered it and this time brought it in hot since my stall speed had increased from the door.

Once I got it low enough I killed the engines to land it but it glid further than I thought it would and hit a small tree! The trunk of the tree smashed the right portion next to the cockpit enough to break the glue joint but not enough to warrant any repairs. It was a very small tree, like the size of my wrist around or so. One of the wires attached to the tree sliced off a portion of one wing tip.

I glued the wing back together, added some velcro straps to the middle of the battery door so that wouldn't happen again and went out for 2 more flights.

Still flies great!
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Old May 27, 2009, 02:09 PM
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USA, FL, Green Cove Springs
Joined Jul 2008
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I'm in the process of building mine - it is my first depron build ever, so we'll see how it goes. I have most of the fuse done, and the wings are together (although a little ugly).

I am using an HS82MG for the wing sweep and I have a quick question - should I cut the mount tabs off of the servo or just open the hole up in the depron mount piece?

Thanks
UJ
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Old May 27, 2009, 02:12 PM
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Neither. You glue those two pieces of foam together then, making sure to have the servo orientation correct you drop it down into the square whole (which you can enlarge if it doesn't fit your servo). When you glue this to the fuse you are basically sandwiching the servo mounting tabs between the fuse and the two foam pieces you just glued together.
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Last edited by sgf323; May 27, 2009 at 02:24 PM.
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Old May 27, 2009, 05:06 PM
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Quote:
Originally Posted by sgf323
Neither. You glue those two pieces of foam together then, making sure to have the servo orientation correct you drop it down into the square whole (which you can enlarge if it doesn't fit your servo). When you glue this to the fuse you are basically sandwiching the servo mounting tabs between the fuse and the two foam pieces you just glued together.

I'm a bit confused. Does this work even with the HS-82? It looks different from the picture from the build. It seems that this would be up too high for the top deck...
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Old May 27, 2009, 05:13 PM
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You can countersink the servo a bit in the foam if you need to so the top is the same, or you can add some foam strips next to the servo so that when you install it the top of it comes up like in the pictures.

IIRC, when I retrofitted my S3102 servo into the plane I added some foam spacers on either side of the servo so that it didn't stick up too high above the deck.
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