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Control Line Forum => CL Building Tips and Problem Solving => Topic started by: billdennis747 on March 06, 2019, 08:11:10 AM



Title: Building a symmetrical-section wing
Post by: billdennis747 on March 06, 2019, 08:11:10 AM
Experts, is there a smart way of building a Peacemaker-type wing? Pin down the spar and jig up the TE? Pin down the TE and have the ribs waving about? Or cut it all in half, build two flat-section wings and glue together?!
Bill


Title: Re: Building a symmetrical-section wing
Post by: Konrad on March 06, 2019, 10:31:32 AM
Don't know what is a Peacemaker.

If only building one of a type I like the pin down the spar and use  thick pieces of balsa to shim the chord  level after marking the chord center line.

I don't like the split in half method as it introduces a joint with its glue weight and potential joint weakness. It also has the same issues with finding the true center line. (In short it gains me nothing).

If building  more than one, I often cut a foam bed  on which to build the wooden wing.

All the best,
Konrad


Title: Re: Building a symmetrical-section wing
Post by: cvasecuk on March 06, 2019, 11:00:05 AM
The Peacemaker build article implies that it is not pinned down at all but just built "in hand". I would at least pin down the lower TE when glueing that, add the upper TE, and possibly do the same for the LE but that would put the ribs well up in the air. I can't remember what I did when I built mine but that was along time ago!!!!!!
Ron


Title: Re: Building a symmetrical-section wing
Post by: billdennis747 on March 06, 2019, 11:12:26 AM
Thanks Ron. I'm doing the similar Firebird (as you know) and yes, I think pinning down the TE first is best and a wide piece of 1/2" to prop up the fronts of the ribs, then the top spar, then flip it over. Sorted!


Title: Re: Building a symmetrical-section wing
Post by: Konrad on March 06, 2019, 12:52:22 PM
http://www.hippocketaeronautics.com/hpa_plans/details.php?image_id=9736

I see George Aldrich didn’t put his name on the plans.

This is real helpful, NOT!!!
"Assemble components in your own favorite manner (on your knee, workbench, or dinning table but keep structure straight , square & warp free).”

With that wing I’d pin the TE down (I actually use light contact spray and build on glass). I’d then slide the ribs on the “Main Spar” (assembly aid) so that the assembly looks like a fish bone. Shim the main spar so that the TE sheet is flat. Align over the plan.  Tack glue the ribs to the TE sheet. Pin one of the LE sheets to the front of the ribs. Make sure all looks aligned. Solidly glue the ribs to the main spar. Glue the ribs to the TE. Install second TE sheet keeping good pressure on the very back of the TE.  Glue top cap to main spar.  Unpin LE bevel LE part line. Apply glue and reinstall LE. When dry flip wing over. Shim again so TE is flat on table. Glue remainder bottom cap to main spar. Prep second LE sheet part line and glue in place.

Then sand away what doesn’t look like a wing.  ::)

All the best,
Konrad


Title: Re: Building a symmetrical-section wing
Post by: tom arnold on March 06, 2019, 01:26:44 PM
While this was written for rubber scale, this might be helpful and worked for me:
http://www.flyingacesclub.com/PFFT/AirfoilSymmetricalDefense.pdf


Title: Re: Building a symmetrical-section wing
Post by: greggles47 on March 21, 2019, 06:49:36 PM
I us in then the topually pin the spar to the plan glue in the ribs, then block up the TE and glue in. Then glue in the top spar, followed by the LE.

This gives me straight wings without any tensions built in.

Alternatively you could build a Peacemaker with a modern construct wing.  Build in your hand with CA.


Title: Re: Building a symmetrical-section wing
Post by: Jez Wilkins on March 22, 2019, 12:21:05 PM
Hi all.

I have a .pdf of the build article for the Peacemaker. Not one of the allowed file types on this Forum and also 58KB too large!! I'll send it to Ratz (Forum Admin) and see what he can do with it for us. :)

Cheers,

Jez Wilkins


Title: Re: Building a symmetrical-section wing
Post by: Indoorflyer on March 22, 2019, 12:31:59 PM
Can you upload it to the plan gallery? The plan is already there.


Title: Re: Building a symmetrical-section wing
Post by: Jez Wilkins on March 23, 2019, 06:52:22 AM
Can you upload it to the plan gallery? The plan is already there.

Hi Indoorflyer.

I've uploaded it into the Combat, Carrier section of the Plans Gallery.  It appears to have uploaded OK and I can currently see a message in the 'Control Panel' section, which says 'Your image will be validated once it has been reviewed.'

Cheers,

Jez Wilkins

Plan with Article http://www.hippocketaeronautics.com/hpa_plans/details.php?image_id=10733


Title: Re: Building a symmetrical-section wing
Post by: EI1638 on March 23, 2019, 08:41:48 AM
Hi Bill,

These days I would ignore the build notes and use a jig. If you've got some larger diameter carbon rod/tube I would use these as guides to hold the ribs in position (2 holes to fit rod/tube in each rib) and 8  to 10 mm OD is fine.

I started using this technique on 40/60 sized CL stunters and its now my default jigging system (unless the wing is too thin or flat bottomed). The rods are supported at their ends to provide clearance for the wing ribs.

Once the rods are  aligned you're almost guaranteed a straight wing. For a peacemaker wing this this would be really easy to set up on the building bench. As ever the hard part is getting the jig aligned correctly in the first place.
As the peacemaker wing (excluding tips) is less than 36 inches (less than one rod/tube length) the alignment should be straightforward. I find its more 'fun' when the span requires two rods to get the length.
The real challenge would then be keeping the fixed flaps straight.

As its a constant chord you could try a traditional "I" beam construction, but this would deviate from the original structure.

No photos I'm afraid as my workbench has disappeared under too many projects (car/house/aeromuddling) at the moment.

Chris


Title: Re: Building a symmetrical-section wing
Post by: Glenn (gravitywell) Reach on March 23, 2019, 09:55:01 PM
I build all my c/l wings on simple two rod wing jig.  Just stack all your ribs together and drill a hole front and back.  Slide them onto arrow shafts (or something else that straight), support them on blocks, and build away.


Title: Re: Building a symmetrical-section wing
Post by: Jez Wilkins on March 25, 2019, 06:14:43 AM
Thanks for the edit to my last post, Ratz, to include a link to the Article for the Peacemaker. :)

Cheers,

Jez Wilkins


Title: Re: Building a symmetrical-section wing
Post by: Sundance12 on March 25, 2019, 12:35:20 PM
I have been using a Jig-stand system for wings that are Symmetrical for a number of years. This works great.
Links for a build here.
http://northof49tech.com/model-aviation/wing-jig-its-wing-building-system/
Here
http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=23972.0