Improve your ARF: make a wing saddle
04-02-2006, 05:52 AM
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Improve your ARF: make a wing saddle
I just finished making a wing saddle for the Ultra Stick 60 that I am assembling. This seems to be standard procedure for me now. Here's my method and it works super. The plane will sound tighter in the air, there won't be wear on the wing dowels, etc., and the wing will fit the fuse like a glove. It takes a lot of strain off of things. Real slick. As someone quoted, a good wing saddle separates the men from the boys, lol.
Remove the covering from the wing saddle area on the fuse. (just where the wing contacts the fuse, nothing radical at all) With the wing off, lay a piece of Handy Wrap (not waxed paper, you want the real thin stuff) over the wing area where it contacts the fuse, and fasten it down with masking tape. It's a bit time consuming to get it on there without wrinkles.... kind of stretch it tight on there. Then mix up a bunch of 30' epoxy and add a LOT of micro ballons to it so it becomes real thick. Smear a little on the fuselage where you have removed the covering, then carefully bolt the wing onto the fuse being careful not to pull or wrinkle the Handy Wrap too much. Then with the plane sitting upside down (for a high wing plane for example) make a fillet with the epoxy mix all along the joint where the wing and fuse meet on both sides of the fuse. Then put a few drops of alcohol or acetone on your finger and swipe it along the joint to make a real pretty fillet on both sides. (Lots of ballons in the mix, so I don't worry about the weight too much)
Let it dry overnight, and then remove the wing bolts and crack the wing loose and remove it. You will have goofy looking flashing sticking out too far on both sides of the fillets you made. Take the fuse outside and put on your particle mask and hit that flashing with your sanding bar until the excess comes off, leaving you a perfect fitting wing saddle. (even after sanding the excess, sharp and ragged flasing off, there will still be a nice little radiused fillet on both sides where the wing and fuse meet) It looks so professional and people really take note of that.
After you removed the covering from the saddle area is the time to check for proper incidence, lateral alignment, etc., before continuing. Don't worry about any gaps between the wing and the fuse since they will be filled in with the epoxy mix anyway!
Ernie
Remove the covering from the wing saddle area on the fuse. (just where the wing contacts the fuse, nothing radical at all) With the wing off, lay a piece of Handy Wrap (not waxed paper, you want the real thin stuff) over the wing area where it contacts the fuse, and fasten it down with masking tape. It's a bit time consuming to get it on there without wrinkles.... kind of stretch it tight on there. Then mix up a bunch of 30' epoxy and add a LOT of micro ballons to it so it becomes real thick. Smear a little on the fuselage where you have removed the covering, then carefully bolt the wing onto the fuse being careful not to pull or wrinkle the Handy Wrap too much. Then with the plane sitting upside down (for a high wing plane for example) make a fillet with the epoxy mix all along the joint where the wing and fuse meet on both sides of the fuse. Then put a few drops of alcohol or acetone on your finger and swipe it along the joint to make a real pretty fillet on both sides. (Lots of ballons in the mix, so I don't worry about the weight too much)
Let it dry overnight, and then remove the wing bolts and crack the wing loose and remove it. You will have goofy looking flashing sticking out too far on both sides of the fillets you made. Take the fuse outside and put on your particle mask and hit that flashing with your sanding bar until the excess comes off, leaving you a perfect fitting wing saddle. (even after sanding the excess, sharp and ragged flasing off, there will still be a nice little radiused fillet on both sides where the wing and fuse meet) It looks so professional and people really take note of that.
After you removed the covering from the saddle area is the time to check for proper incidence, lateral alignment, etc., before continuing. Don't worry about any gaps between the wing and the fuse since they will be filled in with the epoxy mix anyway!
Ernie
04-02-2006, 11:09 AM
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RE: Improve your ARF: make a wing saddle
I've been doing this exact thing on my scratch built 1/2 A Pylon models for several years now.
I don't worry about an exact fit, balsa to balsa, in the wing saddle during construction, just that the froont and back of the wing is making contact with the fuse sides and all is aligned to set the incidence.
The area between the front and back is left as a small (or in some cases not so small, whoops!)gap.
Then after the wing is covered I do the same thing as you have described except instead of tape to hold the plastic wrap, I smear veener sleeder (Vasaline) on the wing and use it to hold the plastic wrap in place. Then apply the Miicro Ballons mix and make a fillet along the fuse side at the wing saddle.
The reason I started doing this was because in AMA's Q-500 rules a wing fillet is not allowed.
I said to myself, "self there's gotta be a reason for this drag wise", so I started doing it to my 1/2 A's.
Did this help my top speed? You got me but I build about a dozen a year and I'm not going to stop now.
I don't worry about an exact fit, balsa to balsa, in the wing saddle during construction, just that the froont and back of the wing is making contact with the fuse sides and all is aligned to set the incidence.
The area between the front and back is left as a small (or in some cases not so small, whoops!)gap.
Then after the wing is covered I do the same thing as you have described except instead of tape to hold the plastic wrap, I smear veener sleeder (Vasaline) on the wing and use it to hold the plastic wrap in place. Then apply the Miicro Ballons mix and make a fillet along the fuse side at the wing saddle.
The reason I started doing this was because in AMA's Q-500 rules a wing fillet is not allowed.
I said to myself, "self there's gotta be a reason for this drag wise", so I started doing it to my 1/2 A's.
Did this help my top speed? You got me but I build about a dozen a year and I'm not going to stop now.
04-02-2006, 06:10 PM
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RE: Improve your ARF: make a wing saddle
Here is a link to a website that that has the same step by step instructions and photos to go with them.
http://www.airfieldmodels.com/inform...dles/index.htm
[link]http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/construction/wing_saddles/index.htm[/link]
I used this technique for the wing saddle area of my UltraSport 40, and it turned out great.
Ryan
http://www.airfieldmodels.com/inform...dles/index.htm
[link]http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/construction/wing_saddles/index.htm[/link]
I used this technique for the wing saddle area of my UltraSport 40, and it turned out great.
Ryan
04-02-2006, 06:54 PM
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RE: Improve your ARF: make a wing saddle
Thanks for you interest. Getting it down is very worthwhile. Although I don't have any step by step photos, I would be glad to go over any part you don't quite understand.
Ernie
Ernie
