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  • December 15, 2018, 01:11:40 AM

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Author Topic: Wing constructin tech  (Read 736 times)

Offline frank williams

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Wing constructin tech
« on: October 04, 2018, 08:27:21 AM »
There was a product review in this months MA that showed a wing construction technique that I thought was neat.  The process is to insert the rib through the spar and then rotate into position.  With laser cuttin now days, there are alot of new options that you would never attempt if you had to cut the parts with a #11.


Offline frank williams

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Re: Wing constructin tech
« Reply #1 on: October 04, 2018, 08:29:08 AM »
more pics

Online Ken Culbertson

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Re: Wing constructin tech
« Reply #2 on: October 04, 2018, 10:33:28 AM »
There was a product review in this months MA that showed a wing construction technique that I thought was neat.  The process is to insert the rib through the spar and then rotate into position.  With laser cuttin now days, there are alot of new options that you would never attempt if you had to cut the parts with a #11.
I agree if you build a "D" tube it would be great for a kit.  I don't like "D" tube so I would probably not use it.
Since it does give you the ability to literally build the entire internal structure before you glue anything, you could put it together and then put it on the jig for finishing, sheeting, etc.  If the kit main spar was not perfectly straight, you are screwed, not even a #2 would save you!

This would be a great time saver if you were mass producing laser cut ARF's.

Ken
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If it is not broke, don't fix it.

Offline MikeyPratt

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Re: Wing constructin tech
« Reply #3 on: October 04, 2018, 12:05:34 PM »
Hi Frank,
When we first received the laser cutter at Sig, Gretz and I looked at different ways to assemble wings and fuselage with this and various other methods.  While they are kind of cool because the laser can make many different shapes to easy construction process.  The main thing that keeps coming back to the both of us was the human and material factor.  We are not cutting metal, it’s balsa and plywood!  Sorting the wood can help this, but nothing down to zero.  Then take into count that many new builders can't get their left or right thing down no matter how good the instructions are.

What we were looking at was attaching the stab & rudder in an ARF fuselage with a cut notch that was basically shaped like that.  It seems really simple at first but let’s say we are using 1/4” balsa that's not a truce .250, thinner its loose, and thicker is Way to tight.  I'm sure that there are some ways this can be used like that, but I'm not sure of a wing and spar assembly.

Later,
Mikey
 

Offline frank williams

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Re: Wing constructin tech
« Reply #4 on: October 04, 2018, 12:45:52 PM »
Hi Mikey
I understand what you are saying.  Creating something for the masses has to be as simple as possible.  They always said that if you design a part that will go on more than one way, that eventually it will be put on incorrectly.  Best to keep it simple. 

By the way….. I have a picture of you that I keep on my cabinet door in the workshop.  Also, a picture of the fluorescent Magnum, pretty plane.

For some of you newer guys that don’t know Mike, there is no finer person in the hobby, and no one with his unique sense of humor.  The enclosed picture is from the ‘90,’91 (?) team trials.  The plane on the ground is mine shortly after I hit a “big bubble” The air was dead still, the flyer before me had put maneuvers on every quadrant of the circle.  I was just doing inside rounds and thought that I felt air behind me, but it wasn’t and the plane pancaked with some authority.

The one person who came to my support was Mike.  He jumped on the carcass like duck on a junebug. I was ready to head for the trashcan.  He had some Sig CA that was the hottest I’ve ever seen.  He also had popsicle sticks for support of the spars that were damaged.   Mike was there.  With his help I was able to make the next flight on time with a pretty good score. 

I’ve always been in great debt to Mike for his support that afternoon. 
Thanks Mikey.

Offline john e. holliday

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Re: Wing constructin tech
« Reply #5 on: October 04, 2018, 01:55:49 PM »
Yes, Mikey is one of the best  Can't remember when I first met him.  Had to have been at the Swope Park Annual meets. H^^
John E. "DOC" Holliday
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Offline MikeyPratt

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Re: Wing constructin tech
« Reply #6 on: October 04, 2018, 09:59:58 PM »
Hi Frank,
Yes it was pretty screwed up, but we had to get you back in the air, you were flying really good until that happened LOL.  I have very few photos of the Magnum Force so if you have the time would you sent me a copy of that photo?  Our small group of stunt flyers that went to many Nat's and Team Trials together always had time to help each other.  We were all very competitive and focused at the Nat's and TT, but if anyone needed help there was always time to help them out.  That is one of the reasons I miss those times and the friendships, I really hope to be able to that again soon.

Later,
Mikey

P.S. Thanks Doc I think it was Topeka.

Offline Dan Berry

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Re: Wing constructin tech
« Reply #7 on: October 05, 2018, 07:27:51 AM »
I would be very leery of the stress-risers at all those square corners.

Offline TDM

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Re: Wing constructin tech
« Reply #8 on: October 05, 2018, 07:44:51 AM »
Frank this is an interesting idea.
There are a few details I am worried about.
1. Difficulty of manufacturing even if you laser cut this. Even though those machines are very precise they a precise pending the material is stable and doesn't move but as soon as you cut balsa it stress relieves and you get misalignment. I had parts laser cut and was wondering why they where not straight.
2. There are a lot of open spaces that eventually catch air and do nothing in the finished wing. They are neither sheer webs nor spars, that go along for the ride unless they are filled in which it adds weight yet again.

The same can be achieved following your original idea by different approach. Make a spar that has notches in it  which interlocks with notches in the ribs. More over I would add .5in legs on the bottom of the ribs so that when you place the ribs on a flat table the legs will keep the wing in perfect flat plane (these legs can be placed behind the main spar and in front of the rear sheeting). The idea is that you build a puzzle ribs main spars (one top one bottom trailing edge maybe then place on a flat table and check for squareness and tack the legs on the rib right on the table. From that point on you are golden because the frame is level you have access to everything and potentially build the whole wing in a one hour session. After the frame is on the table glue all joints then add the bottom sheeting and trailing edge sheeting on bottom then you add the sheer webs followed by top sheeting. the only thing missing at this point is the tips and center sheeting.
Each goal you meet is a moment of happiness
Happiness is the harmony between what you think and what you do. Mahatma Gandhi

Offline frank williams

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Re: Wing constructin tech
« Reply #9 on: October 05, 2018, 08:54:46 AM »
Actually I went back to the MA  article and saw that the kit in question was a BMJR kit.

TDM - Actually the wing that I have been building for the last decade or so has interlocking notches in the spars and in the ribs also.  This automatically locates the ribs.  The spars are built with 1/16x1/4 spruce tops and balsa webs with notches.  The wing is built on a flat surface with 1x2 hardwood supports for the wing build.  Leading and trailing edges that sit on the lip of the 1x2's are also notched to locate the ribs fore and aft.  The wing is quick and easy to build and turns out very torsionally stiff.  See att.

Offline Howard Rush

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Re: Wing constructin tech
« Reply #10 on: October 05, 2018, 12:56:43 PM »
After you laser cut your first project, you wish you had a laser head that rotates to cut angled spar slots. 
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