Covering the razor back.

[aviator79]

I'm going to do this tomorrow, hopefully with the one-piece method. I have heard that with a 225 iron and patience, it can be heat formed to follow the contour. Does anyone have any tips or lessons learned to share before I dive into the breach?

[Esser]

Lessons learned: do it in the two piece method especially if you are short on fabric.

I tried to do it in one and wish I had gone to two from the get go. The only difference I would do is make each of the two pieces be the side pieces of the fuselage at the same time.

If you want to try it, go for it! I know people have pulled it off. I wasn’t one of them.

[AirFox]

Hay Brian, I did a write up on how I did it with 1 piece on my build page. Looks nice without all pie shapes cut into the seam on the razor back. I'm still really happy with it after 4 years. Good luck.

http://www.teamkitfox.com/Forums/showthread.php?t=4013&page=6

Scott

If the link doesn't work go to page 6 of Noble Build.

[aviator79]

Hey Scott, did you heat-form at all, or just pull through fabric back to the corners once the top, front, and partial sides were glued? Did your first two attempts result in scrapped fabric? I might have enough for two attempts.

[aviator79]

I'm going for it. Only the super-hard part left to go! It looks to me like it's going to work though. I hope so, because I may not have enough fabric to try again.

It is definitely too soon to spike the football. I'll post again when the fabric is either shrunk or torn off and burned.

https://lh3.googleusercontent.com/Uls9dWzckilG0fhqSLBm2P6l6_IBDKIjg-iD_aLn_3Yc_IWi8acTGPKmYjjulMQ6wkCqMw-cddtB7FiGnPBvA_ur6qbAVqGCJ-jk8slsbKW_gYSpdc-mErJDu1Dbn3Gk37w5TrffuiU=w600

https://lh3.googleusercontent.com/j5xJA_q3ydwVpQu-kTod0bxGYdQKg6nwZfrFmloFc6aUb9W4L6UpVwGB4bB9jmt6bh IbygFfBubpzvpOIDBg9WDC1VHywbwTq30q1MBQfACtxzPY0d70 Ly0zBuGCEbm1bH8PZYIVXUI=w600

https://lh3.googleusercontent.com/GdePHmg59EHydwiM9fDT7yqF3ptNb1qlEnyvb6xLEQOJQ7DTNB lrpLja6AuPb-r8CVmJcglDqAL490QzeQM0tQev9qEP0dp1iJfbmEU-glXvVElA9mrIj9LEeKJL70DZMNjS87FZ3-U=w600

[Tom Waid]

My pictures are here. (http://tropicaltuba.com/Kitfox%20Project/Kitfox11.htm#Covering%20the%20Fuselage%20Continued )

When heat shrinking the razorback remember that ever square inch of the fabric has to be touched with the iron. This means working it into all the folds. With patience the folds will disappear.

[efwd]

I can already tell your going to be fine. Your even going to like the way it turned out.
Eddie

[aviator79]

Well, I don't know.

It looks fine, but it took all the shrink to get the slack out, and the fabric feels looser than it should in the curve. Has anyone else experience this? I'm thinking about getting some more fabric and trying again. I don't want it to flutter in the slipstream.

Before shrinking:
https://lh3.googleusercontent.com/hu4MqpC_832Bi7eEr0hT9b9sRUKbzRFVppmAcnhUoGmJ8c55Un NuiPlz2q5ZhqbCGP0lllvAn04sMMfOQkU5WQwvs8wXVoTGuY0u wvKacloRoGhVf-dgBf1q4FcOxmr-g53Ourx-ujQ=w800

https://lh3.googleusercontent.com/xdNauMi-iQw0jpkYO0TOC3ghrMxqjgK6uPD3BRRMkKoAz8wxBPnalcMXZF Ra8J2rBJk1ZXSd957AtSeW7zCmnFhWN28tglvq7g_a6SDUwXpK x8Snt0spLmvy_MGLT1hzA8zXxRJNxqw=w800

https://lh3.googleusercontent.com/xdNauMi-iQw0jpkYO0TOC3ghrMxqjgK6uPD3BRRMkKoAz8wxBPnalcMXZF Ra8J2rBJk1ZXSd957AtSeW7zCmnFhWN28tglvq7g_a6SDUwXpK x8Snt0spLmvy_MGLT1hzA8zXxRJNxqw=w800

After shrinking:
https://lh3.googleusercontent.com/4HQPBXgeYonJ9L00DvfZc6T5da6OB-O05Qf1fmBT1r3PANJyTnZzTNsrNseakqKSdS0IAlTIgNS1iqqX y5Wdh2bJOeDPsBNb01TYc3-oxSnuy57KsMjoaycwWWRvor-CHrDJD2OCI8g=w800

[Esser]

I didn’t like the “feel” of the tension on mine either when I was trying it. Looks like you had a good first try!

[AirFox]

Nice work Brian! Don't forget to order some Bias tape for that transition. You will also use it for the top of the Vert, Horiz and Elevator. You are going to be happy with those results.

Scott

[aviator79]

Actually Scott, I think I'm going to redo it. I don't like the lack of tension in the fabric right up by the wing holdback tube. There are no wrinkles, but there is very little tension. The bummer is that I don't have a piece of fabric big enough to try the one-piece method. I need to either get some more fabric or settle for the two-piece installation.


I do have some bias tape. My horizontal stab, rudder, and elevator are done and painted!

[Tom Waid]

Mine also had a "looser" feel but, after the application of bias tape and paint, it feels fine. Not to say that your experience will be the same. I'm relating my experience.

[jmodguy]

try a little more heat....

[rosslr]

What temp was your final shrink?? there is a temp at which the fabric looses it 'tension' and therefore will never regain the tension achieved at the optimal final temp. It looks good though - I too ended up with extra fabric and the two piece method - looks fine.

good luck and don't settle for not being happy with the result or it will bug you for a long time!

r

[PaulSS]

I have to agree with Jeff. IF you're going to strip the fabric off anyway, why not give it a bit more heat and see if it tightens up a bit more. You've got nothing to lose......IF you're going to remove it.

Something about Young's Modulus rings true in Ross' statement but them's fancy fizics, so get the iron out and see if it goes tighter before you tear it off.

[rosslr]

The polyfibre manual says something like "....above 350' the fabric becomes permanently looser...'

I found that is true.....!

cheers

ross

[David47]

Agree with Ross. Tested at 390’ on a test piece and the fabric went slack. Be careful going beyond manual limits of 350’.

[aviator79]

I did the final heat shrink to 350, and even if I could have pushed it to 375 without damaging it, the addtional shrink would not have been enough to get the tension correct. Also, there's not a household iron out there that maintains temperature well enough to skirt the line that close. The lack of tension was one of those things that would have bothered me, even it it turned out to be no big deal. So I tore it off, and re-did it with two pieces, and I'm very happy with it. I'm more than happy to compromise on a minor aesthetic consideration to feel comfortable that the fabric is at the correct tension. It may not seem like it until you try it, but the compound curve there is such that you're really making a big demand of the fabric to conform to it.