How do YOU do iron on fabric undercambered wings ?
06-19-2002, 07:30 AM
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How do YOU do iron on fabric undercambered wings ?
Calling all "early flyer" fans !
How do you ensure good, lasting adhesion when covering an undercambered wing with iron on fabric coverings ?
Please respond - is there an alternative to stitching ?
fiery
How do you ensure good, lasting adhesion when covering an undercambered wing with iron on fabric coverings ?
Please respond - is there an alternative to stitching ?
fiery
06-19-2002, 06:44 PM
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How do YOU do iron on fabric undercambered wings ?
I've used dope, Balsa rite, thinned glue etc. I've gotten it to stick and stay but not what I would call good, lasting adhesion.
06-19-2002, 09:23 PM
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How do YOU do iron on fabric undercambered wings ?
I haven't used iron-on fabric but with monokote I started by tacking the monokote piece to the middle of the chord on all ribs (helps if a spar is available.)
Then iron down the front of the mid span rib and then move out every other rib and do the same until you get to the root and tip. Then hit the ribs you missed. If you have tacked to a spar, you can shrink the front section.
After the front is done, do the same thing on the rear portion of the ribs.
Go over the entire thing again to make sure everything is stuck down then shrink as normal.
I covered a 120" sailplane wing with this method and didn't even disturb the built in washout. I was amazed as it was only the 3rd airplane I ever monokoted (I was a dope and tissue/fabric man for a long time)
With fabric, it would be about the same but if you're unsure, I would say dope and silk would be an easier way to do it. Just make sure the ribs are sanded smooth for max adhesionand that the dope used to tack the silk down is dry and every rib is stuck down well (use a piece of tape to try to lift the material). Then dope the entire surface to shrink.
Don
Then iron down the front of the mid span rib and then move out every other rib and do the same until you get to the root and tip. Then hit the ribs you missed. If you have tacked to a spar, you can shrink the front section.
After the front is done, do the same thing on the rear portion of the ribs.
Go over the entire thing again to make sure everything is stuck down then shrink as normal.
I covered a 120" sailplane wing with this method and didn't even disturb the built in washout. I was amazed as it was only the 3rd airplane I ever monokoted (I was a dope and tissue/fabric man for a long time)
With fabric, it would be about the same but if you're unsure, I would say dope and silk would be an easier way to do it. Just make sure the ribs are sanded smooth for max adhesionand that the dope used to tack the silk down is dry and every rib is stuck down well (use a piece of tape to try to lift the material). Then dope the entire surface to shrink.
Don
06-20-2002, 01:59 AM
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How do YOU do iron on fabric undercambered wings ?
I've used fabric on an Eppler 423 airfoil wing with a span of 118 inches. I started at the root of the wing and used the iron to tack down the covering to every point possible doing the best job I could until I reached the tip. As I moved out from the root of the wing, I started tacking the covering down at the center of the undercambered area and worked my way out to the LE and TE. After it was all tacked down, I got the wrinkles out with the heat gun. I used D-tube construction so the only hard part was the latter half of the wing. The wing came out great. It was easier than I thought it would be. The fabric can also take more heat which made it easy to remove the wrinkles on the bottom.
This process worked for me but someone else may have a better way.
Here is the wing on the plane after winning 3rd place in the SAE heavy lift cargo competition in Palmdale, CA two weeks ago. It lifted 25.2 pounds of steel for a total weight of 34 pounds with an OS 61 FX motor.
Sorry, just had to show it off.........
This process worked for me but someone else may have a better way.
Here is the wing on the plane after winning 3rd place in the SAE heavy lift cargo competition in Palmdale, CA two weeks ago. It lifted 25.2 pounds of steel for a total weight of 34 pounds with an OS 61 FX motor.
Sorry, just had to show it off.........
06-20-2002, 11:24 AM
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Re: How do YOU do iron on fabric undercambered wings ?
Originally posted by fiery
Calling all "early flyer" fans !
How do you ensure good, lasting adhesion when covering an undercambered wing with iron on fabric coverings ?
Please respond - is there an alternative to stitching ?
fiery
Calling all "early flyer" fans !
How do you ensure good, lasting adhesion when covering an undercambered wing with iron on fabric coverings ?
Please respond - is there an alternative to stitching ?
fiery
Butyrate is fine for fuel proofing and shrinkng but, Nitrate is the choice for gluing the fabric on.
With iron-ons, I sometimes use balsarite, works well too.
06-21-2002, 08:18 AM
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Iron on fabrics and undercambered wings
Hi 2 Piece!
Do you mean, just go over it (carefully) with the covering iron, and not use the heat gun, once it is "tacked" down to the ribs and spar which have had the "stix-it" treatment?
Do you just coat the bottom of the ribs and the spar? Or the adhesive side of the fabric as well?
More info. please!
Regards
fiery
Do you mean, just go over it (carefully) with the covering iron, and not use the heat gun, once it is "tacked" down to the ribs and spar which have had the "stix-it" treatment?
Do you just coat the bottom of the ribs and the spar? Or the adhesive side of the fabric as well?
More info. please!
Regards
fiery
06-21-2002, 12:11 PM
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How do YOU do iron on fabric undercambered wings ?
fiery, two coats Stiks-It or Balsa Right to bottom of ribs. I do not put the Stiks It on the covering itself. The WWI, under cambered, wings I've built all had cap strips on ribs so I cannot comment on weather or not you would apply it to the spar. Thin/ reduce the first coat about 25% with dope thiner-this helps it soak in the wood. Second coat straight out of the can.
Using an adhesive backed fabric covering, ie. Solartex, Worldtex, Coverite, Nelson Lite Fab, lay fabric on bottom of wing. When working with an under camber wing I do not tack any of the covering on the bottom of the wing, iron it directly to ribs. Start with the rib in the center of the wing and begin to iron the covering down just to the rib. Work your way to both ends of wing ironing the covering down to just the ribs. Do not shrink/ iron the fabric between the ribs at this time. Then iron down the leading and trailing edges along with the root and wing tip. Then take the iron and carefully iron/ shrink the fabric in between the ribs, avoid ironing over the ribs. Use a low heat setting to shrink the covering in between the ribs- say 250-275 degrees Fahrenheit- sorry I don't know Celsius equivalent. You want to shrink the covering between the ribs without re-activating the heat sensitive adhesive already ironed down to the ribs. Do not use a heat gun. In fact I wouldn't even use a heat gun when shrinking the covering on the top of the wing. All the under cambered wings I've built are quite thin, and using a heat gun to shrink the covering on top of the wing could produce enough heat to soften the adhesive on the bottom ribs. Thus pulling the covering away from the rib. When done this will produce a very strong bond, the wood will break before the covering comes loose.
I also put a coat of Stiks It down where ever I over lap the fabric coverings. Along leading, trailing edges and wing tips where the top piece overlaps the bottom piece. This helps fill the weave and provides a good base to iron the top piece to.
2Piece
Using an adhesive backed fabric covering, ie. Solartex, Worldtex, Coverite, Nelson Lite Fab, lay fabric on bottom of wing. When working with an under camber wing I do not tack any of the covering on the bottom of the wing, iron it directly to ribs. Start with the rib in the center of the wing and begin to iron the covering down just to the rib. Work your way to both ends of wing ironing the covering down to just the ribs. Do not shrink/ iron the fabric between the ribs at this time. Then iron down the leading and trailing edges along with the root and wing tip. Then take the iron and carefully iron/ shrink the fabric in between the ribs, avoid ironing over the ribs. Use a low heat setting to shrink the covering in between the ribs- say 250-275 degrees Fahrenheit- sorry I don't know Celsius equivalent. You want to shrink the covering between the ribs without re-activating the heat sensitive adhesive already ironed down to the ribs. Do not use a heat gun. In fact I wouldn't even use a heat gun when shrinking the covering on the top of the wing. All the under cambered wings I've built are quite thin, and using a heat gun to shrink the covering on top of the wing could produce enough heat to soften the adhesive on the bottom ribs. Thus pulling the covering away from the rib. When done this will produce a very strong bond, the wood will break before the covering comes loose.
I also put a coat of Stiks It down where ever I over lap the fabric coverings. Along leading, trailing edges and wing tips where the top piece overlaps the bottom piece. This helps fill the weave and provides a good base to iron the top piece to.
2Piece
06-21-2002, 02:41 PM
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How do YOU do iron on fabric undercambered wings ?
Sorry, when I said tack I should have said ironed. I ironed the covering to every available rib. Starting in the middle of the rib and working out to the LE and TE. Same process, just different words. I used coverite on both wings. Tack everywhere, iron - same thing. Stik it would be worth using as mentioned above.
2 piece, what you said would work wonderfully. I don't want to argue, but I've used heat guns on undercambered airfoils with coverite a lot without any problems. I've had one of the wings warp on me sitting in 110 degree weather in the sun. I went over it three times with the heat gun to remove the warp with semi-high heat without any of the covering coming loose, even without the stik it. I'm not saying do it, but it does work without pulling the covering loose. Maybe other materials would handle it differently. I found Covertie user friendly. If in doubt, don't use the heat gun. Maybe, I just got lucky (4 times).
2 piece, what you said would work wonderfully. I don't want to argue, but I've used heat guns on undercambered airfoils with coverite a lot without any problems. I've had one of the wings warp on me sitting in 110 degree weather in the sun. I went over it three times with the heat gun to remove the warp with semi-high heat without any of the covering coming loose, even without the stik it. I'm not saying do it, but it does work without pulling the covering loose. Maybe other materials would handle it differently. I found Covertie user friendly. If in doubt, don't use the heat gun. Maybe, I just got lucky (4 times).
