RE: Building a built-up pattern stab and wing
 

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RE: Building a built-up pattern stab and wing
 

Last of stab.

RE: Building a built-up pattern stab and wing
 

Hi Dave,

Stab weights of 100 grams is more than I expected. My Spark Dynamic composite stabs weigh 105 grams each without servo. Having said that, 19/20 grams for a sheet of 1/16" balsa is heavy. Half that weight would be the norm for skinning foam cores.

What is the best weight you have achieved with light wood?

What is the average weight of the wood used to cut your wing/stab kits?

Regards,
Jason.

RE: Building a built-up pattern stab and wing
 

Hi Jason, the plans indicate 1/16" wood for sheeting but I need to remove that, my mistake, the 1/16" wood sheeting is very fragile so I've been doing all my sheeting with 3/32" wood. The ribs are spaced about 2-1/2” apart and if you sheet a wing with the ultra-light balsa you use with foam cores the sheeting will fail, the foam is bracing the wood.

The kits are 3/32" wood too, some say this could be 1/16" but at times it's hard to assemble the wing with the thicker wood due to the deep, relative to thickness, cutouts in the ribs, I would hate to try 1/16” for ribs. If you can get 14 to 16 gram 4”x36” long sheets the wings and stabs will be light, I finished my elliptical wing several weeks ago and they weigh 8 oz each, 226 grams and 229 grams, I'm anticipating 12 oz ready to fly panels when finished with servo. As an experiment I have sheeted several stabs and one wing with 1/16" wood, they are prone to damage before monokoting but hold up well after the finish is on. When I did sheet with 1/16" wood I used the same weight per sheet as the 3/32", this way the wing/stab is sheeted with denser wood and will resist any handling damage.

Earlier in the thread Colin indicated his stab panels finished with servo were 3.5 oz, he used very good wood to achieve that weight. At times it’s very difficult to find the light wood and the cutter this time had two stab rib sheets on the heavier side. This is why I state the finished ready to fly weight without servo should weigh about 3.5 oz, at this weight Colin would have save about an once per panel, 3.5 oz + 1 oz for servo, not his great results of 2 oz per panel.

Hope that helps.

Dave

RE: Building a built-up pattern stab and wing
 

It sure does Dave.

Looking at your picture I thought it was thicker than 1/16"....

12 ounce (340 grams) wing panels sound great. The wings on my Spark are 400 grams without a servo and extension etc.

Cheers,
Jason.

RE: Building a built-up pattern stab and wing
 

Thanks for posting this build. I am getting ready to build a Starcraft Addiction 110, and the details about how to sheet the wing are very helpful. Thanks!

RE: Building a built-up pattern stab and wing
 

Thanks for the build thread Dave.

Vince

RE: Building a built-up pattern stab and wing
 

I was able to start the wing today with the first step in making skins and gluing one panel frame together. I've included the plan for the wing and the first group of pictures, please let me know if there are any questions.

Dave Snow

RE: Building a built-up pattern stab and wing
 

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RE: Building a built-up pattern stab and wing
 

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RE: Building a built-up pattern stab and wing
 

Hello Dave,
very nice project,
which airfoil did you choose ?
Jérôme

RE: Building a built-up pattern stab and wing
 

It's from the Spark Evo wing.

Dave

RE: Building a built-up pattern stab and wing
 

How did you get the parts (ribs and jigs) cut? Did you copy a kit or copy the airfoil on CAD to produce the parts?
GREAT looking build!!
Thanks for sharing!

RE: Building a built-up pattern stab and wing
 

The kits prior to this one are copies, almost identical to the original, of a wing; I make a tracing of the wing outline with aileron location / tube / adjuster / hold on locations...., make a tracing of the root rib and then transfer the information into AutoCAD. After that is drawn I then locate the ribs and spars and draw all the pieces for the wing and jig. I then repackage the ribs and spars for the laser cutter, AK Models in Iowa, and he cuts the kits for me.

Dave

RE: Building a built-up pattern stab and wing
 

Hi Dave,
Thanks for the informative response. If I contact AK Models would I be able to purchase a 'kit' from them. I assume they only have the parts information; so could I get a copy of the plans from you?
Thanks,
Will

RE: Building a built-up pattern stab and wing
 

You can buy the kit through me, [email protected], once I receive an order I send the request to AK Models and they cut the kit and I have them either send it directly to the buyer or to me. If the buyer can plot the PDF plan then sending it direct saves some on shipping otherwise when I receive the kit I add the plan when sending it to the buyer. It usually takes about a week for the cutter to make the kit but around holidays it could take longer. I do not keep any kits in stock but I can tailor the dihedral root rib slightly if the wing is to be mounted on an existing airplane.

Dave

RE: Building a built-up pattern stab and wing
 

For the panels I built I used 4-6lb sheets and screened all the sheets used for a maximum weight of 18gms. I ordered a box of 10 sheets and got only 4 that were 18gms or less. I'm also not using a hardwood dowel for the horn....instead I'm going with a carbon horn glued into the balsa block.


Colin.

RE: Building a built-up pattern stab and wing
 

Gluing in the shear webbing, cutting the sheets and adding the leading edge sheet, setup and gluing the socket in the panel.

One of the pictures shows how much material needs to be removed at times to straighten the sheet edge.

The jigs have all the rib centerlines the same distance from the table top so to set the dihedral the tip is blocked up and the tube is set parallel to the table. The frame/jig is placed over the plan to verify the real tube is aligned with the plans tube. After the dry fit the pieces can be glued together, I used the Poly-U this time but I've also used 30 minute epoxy at times.

One issue that I've had is with the plans; they are never printed to the exact full size, with the jig this is not a big problem because the jigs are the full size and the plan is used as a reference when building the jigs to get the proper geometry.

Dave

RE: Building a built-up pattern stab and wing
 

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RE: Building a built-up pattern stab and wing
 

Dave,

Your design is an engineering masterpiece. Thank you for sharing with all of us.

Jeff

RE: Building a built-up pattern stab and wing
 

Hi Dave,

Beautiful work! I may have to order a set for myPassport. Do they have the SFG?

Check your plotters calibration they can drift. Plotting directly from CAD is much more accurate than PDF.

Anthony

RE: Building a built-up pattern stab and wing
 

Just curious why you didn't tie the socket doublers to the shear web or wing skin? I think you are missing an oppertunity for a good strength increase with vitually no weight gain. Been enjoying the thread so for though.

RE: Building a built-up pattern stab and wing
 

Thanks Jeff.

No SFG's, I was thinking the wing kit would be a direct replacement for an existing wing. The last rib has holes for blind nuts that should line-up with the holes/screws for the tips from CA Models. Here’s the plan for the PassPort/Visa wing.

Anthony we've tried several plotters and all have the same issues, I think it could be the plans are 84" long and the distortion may be within the plotters tolerances.

The doublers will actually make contact with the skin after the glue for the doubler is set, I have a picture in the next group that shows the glue needs to be ground down flush with the ribs. I could have extended them to the shear webbing but 1) so far there has not been a failure that I know of in this area, 2) in foam wings there is usually less structure at the end of the tube than the built-up wings have so I did not think there would be a need, 3) this makes construction easier when installing the socket - some flexibility in make the rib holes larger if needed to get the exact dihedral and placement of the socket.

Dave

RE: Building a built-up pattern stab and wing
 

Cleaning up ribs after socket glued in, finished sanding / sizing and matching weights of skins, gluing second socket and clean-up, pinning frame and skin to top and bottom jigs, gluing ribs and pressing.

The top of each panel will be completed first, some internal work then attach bottom skin.

Dave

RE: Building a built-up pattern stab and wing
 

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