HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 14, 2013, 07:19 AM
Registered User
sroge's Avatar
Germany
Joined Sep 2010
88 Posts
Question
Basic concepts of building a wood sheeted wing?

Hi,

I recently wondered if there are any comprehensive surces on the internet on how to build a balsa or abachi sheeted wing based on ribs.

I got some experiences with standard wings covered with Koverall or Oracover. But as I am going to build a 3D plane with a rather sophisticated airfoil geometry, I want to make sure that the shape of the whole wing is exactly as intended and there are no inaccuracies which usually appear when convex sufaces are being covered by fabric or foil.

So I will build ribs of balsa and/or plywood and cover them with wood. I have been looking around but I did not find really good sources of information.

Who can help me?

Thanks,
Stefan
sroge is offline Find More Posts by sroge
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 14, 2013, 08:32 AM
What, Me Worry?
edbu1's Avatar
United States, FL, Sanford
Joined Feb 2007
261 Posts
I'm not sure I understand what you're not sure of, but yes, you frame up the wing using spars, accurately cut ribs, leading edge and trailing edge. Typically, you will have the framework pinned to your flat building board and then sheet the top of the wing. Butt glue the sheeting pieces to each other. You want to take your time to sand the edges that will be butt glued together to ensure a snug fit with no gaps. I use a 36 inch sanding bar and check for alignment of the pieces before gluing together. You may need to glue 2, 3 or 4 pieces together depending on the width of your wing and the width of the wing skin pieces. Glue the skin pieces together with the grain going lengthwise. The grain will also be lengthwise along the wing. You want the grain to be perpendicular to the ribs, so if the wing leading edge is tapered, cut and sand the skin that you have just created to match this taper. Then you can glue the top skin to the leading edge and to the ribs. Keep the framework pinned to the building board until after the skin is attached to help ensure the wing stays true. Then you can remove the wing from the building board and trim any excess wing skin. Glue together wing skin pieces for the underside of the wing and glue to the underside being sure to glue to the entiire length of the ribs so that the skin follows the contour of the underside of the wing, particularly with convex airfoils. Here's where you need to be gentle so as not to cause wing distortion. As for glue, I typically use a slow CA and first glue the skin to the leading edge. Then add glue to each rib about 2 inches each using a CA glue tip and then press the skin down with the long sanding bar until set and continue. You can catch any missed spots when you remove the wing from the building board. Can't do that when the bottom skin is in place, though!
edbu1 is offline Find More Posts by edbu1
RCG Plus Member
Old Jan 14, 2013, 09:06 AM
The Prez....... again
kenh3497's Avatar
United States, IA, Rockwell
Joined Jul 2011
4,321 Posts
I wish I could fine it again but I saw a build thread of a 2M pattern plane. In the kit was a wing jig/cradle that was a built up of "ribs" that matched the ribs of the wing. You built the base structure, ribs and spars, then sheeted the wing in the cradle. It looked almost foolproof. Here is a good tutorial on building wood wings. http://www.airfieldmodels.com/inform...tion/index.htm

Ken
kenh3497 is offline Find More Posts by kenh3497
Last edited by kenh3497; Jan 14, 2013 at 09:13 AM.
Reply With Quote
Old Jan 14, 2013, 12:03 PM
Scale Builder
United States, AZ, Litchfield Park
Joined Jul 2002
2,606 Posts
Here is how I build the outer wing panels on my 1/8 scale Hellcat. It uses jig tabs while assembling the basic structure and sheeting the top surfaces. The panels are then put into a saddle to hold them in correct alignment while all the "innards" are installed and the bottom sheeting is applied. It's one way of skinning the cat anyway.

http://www.hellcat.cwvmodels.com/panel.html
Chad Veich is offline Find More Posts by Chad Veich
Reply With Quote
Old Jan 14, 2013, 01:50 PM
An itch?. Scratch build.
eflightray's Avatar
South Wales U.K.
Joined Mar 2003
13,805 Posts
Quote:
Originally Posted by sroge View Post
Hi,
.................................................. .

But as I am going to build a 3D plane with a rather sophisticated airfoil geometry,
.................................................. ....

Thanks,
Stefan
I always ask the awkward question, sorry.

Why do you need a 'sophisticated airfoil' for 3D, when much of the time a 3D model is flying very slow.
There are also many 'flat sheet' airfoil 3D models that seem to fly quite well.

Plus adding sheeting to a wing is also adding weight, not always a good thing if trying to hover.

But as a slight help, (well I do try at times, ( some people even say I am 'very trying' )), there is a - Balsa Builders forum - that may have all the infoormation you need.
Also a quite good - 3D Flying forum - that may be worth looking in if you haven't already.
eflightray is offline Find More Posts by eflightray
Reply With Quote
Old Jan 14, 2013, 01:57 PM
An itch?. Scratch build.
eflightray's Avatar
South Wales U.K.
Joined Mar 2003
13,805 Posts
Woops!, sorry, I forgot some people still fly those old IC powered models.

Here's the - 3D / Fun Fly Fuel Planes forum
eflightray is offline Find More Posts by eflightray
Reply With Quote
Old Jan 14, 2013, 07:20 PM
KE your cub.
Curare's Avatar
in the gutter, again....
Joined Jun 2005
4,217 Posts
Quote:
Originally Posted by kenh3497 View Post
I wish I could fine it again but I saw a build thread of a 2M pattern plane. In the kit was a wing jig/cradle that was a built up of "ribs" that matched the ribs of the wing. You built the base structure, ribs and spars, then sheeted the wing in the cradle. It looked almost foolproof. Here is a good tutorial on building wood wings. http://www.airfieldmodels.com/inform...tion/index.htm

Ken

Look up the Bob hunt lost foam method of building wings, it's pretty much the best and lightest way to go. He still does open panel, but you can easily fully sheet the wing.


I also tend to agree with eflightray, about your airfoil selection. What are you hoping to acheive? Also, there are better ways to get good fidelity to the airfoil shape (if it's that complex, changes in airfoils of .003" can effect performance) than balsa and ply.

Are you sure you're not making a big rod for your own back?
Curare is offline Find More Posts by Curare
Reply With Quote
Old Jan 18, 2013, 09:38 AM
Registered User
Florida
Joined Dec 2001
390 Posts
Sroge - I haven't done the math but if you actually measure the sag of the covering between ribs your actual airfoil will probably be close to the average of the rib thickness and thickness at the greatest amount of sag (the mid-point between two ribs).

Instead of fully sheeting the wing you could make the rib thicker so that the average airfoil is the airfoil you want. I don't know how that would work exactly because I never worried about it before and haven't tested it.

The other option is to just use more ribs. Make them from contest balsa. You'll add maybe an ounce of weight to the plane - insignificant.

Take a look at this article on my website. If you pick your wood properly ribs weigh just about nothing unless the rib has something else it has to do like support landing gear mounts.
CafeenMan is offline Find More Posts by CafeenMan
Reply With Quote
Old Jan 18, 2013, 02:21 PM
Registered User
Florida
Joined Dec 2001
390 Posts
Oops. Forgot the link:

http://www.airfieldmodels.com/inform...ircraft/03.htm
CafeenMan is offline Find More Posts by CafeenMan
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Fixing a delam on a wood sheeted, film covered wing? Brian Courtice Slope 13 Jul 26, 2006 09:43 PM
Question Is there a wood-sheeted DLG wing? will_newton Hand Launch 4 May 07, 2006 10:17 PM
Vacuum bag, wing press, or contact cement for sheeting wings with wood? surfimp Slope 53 Dec 13, 2004 01:00 PM
Question bagging wood sheeted wings kevin kavaney Composites Fabrication 2 Jun 26, 2004 02:49 PM
Obechi wood wing sheeting droydx Slope 2 Mar 01, 2004 12:40 PM