turtledeck

[Rynoth]

I have seen on a lot of builder blogs/websites where they rivet the spine of the turtledeck before doing any fitting of the formers. I did not do this (and don't see where it's called for in the plans, not to mention it makes riveting the spine angles much more difficult) and I wonder if this method is more likely to cause these dimples/waviness.

I did not modify my formers in any way, I did not use spacers or shims. I used light pressure when riveting (all of the rivets turned out good both sides) and I have pictures of my completed turtledeck here: http://www.rynoth.com/wordpress/waiex/2 ... ompletion/

I might have been lucky. I do recognize some subtle indentations around each rivet hole on the turtledeck, but would expect no less of a pressure point spaced inches from other pressure points around a curving structure.

[sonex892]

I have seen on a lot of builder blogs/websites where they rivet the spine of the turtledeck before doing any fitting of the formers. I did not do this (and don't see where it's called for in the plans, not to mention it makes riveting the spine angles much more difficult) and I wonder if this method is more likely to cause these dimples/waviness.

This may well be the way to go for a matched hole kit. For an older kit, Pre matched hole kit or a plansbuilt, I would Not recommend fitting the turtledeck formers first.

First put the turtledeck in place, then the aft former, then the forward formers, then the ones in between, this way you'll be able to position them correctly in order to have minimal bumps and waves.

For older kits or plans I agree with Micheal's sequence.

Steve
Sonex 892
VH-ZSX 3300 TD 140hrs

[Rynoth]

First put the turtledeck in place, then the aft former, then the forward formers, then the ones in between, this way you'll be able to position them correctly in order to have minimal bumps and waves.

For older kits or plans I agree with Micheal's sequence.

I agree with that sequence as well for all kits, maybe I wasn't clear... I'm not sure why one would rivet (versus cleco) the spine before fitting the turtledeck to the fuselage, then adding the formers and pilot drilling. As a result, you can updrill the spine AFTER the formers are in position. I left the spine clecoed and riveted it last after everything else (including former riveting) was done. Again, this might not actually have anything to do with the dimpling some people get, just something to consider.

Here is how I initially mounted the skin and the formers. http://www.rynoth.com/wordpress/waiex/2 ... eck-cleco/

Another factor will be the overlap the turtledeck skins have where it joins the side skins at the upper longerons. Making sure you have full overlap should have the effect of snugging up the skin to the formers. I do remember having to use a fair bit of pressure to slide my formers into position, which probably helped fill the air gaps.

[Area 51%]

I am currently having the same issues with my formers. Not dimpling of the skin ,as I have not yet gotten to that point, but the flanges in the #5 former are flat and will undoubtedly cause the skin to pucker. Puckering aside, I'm even wondering if the skin can be distorted enough to get the gap closed for effective riveting. Draw a 9" diameter circle, then try to match the inside of that circle using toothpics and you'll see the gaps I'm dealing with.

I looked in the Sonex web store, and the picture of the former seems to have flutes rather than cutouts like mine, and also looks to have an actual curve to it instead of being made up of a series of straight lines. I ordered it. We'll see.

Another issue with the #5, is the first flange on each side of center doesn't co-exist with the hole lasered into the skin. Not quite sure how the engineers could miss that flange by 1/4".

As long as I'm whining about that former, the "matched holes" that line up with the holes on the shear web stiffener, do not allow for any movement side to side of the former to even out any gap between said former and the skins.

If anyone still has nothing better to do than to read this, my #1 formers are also keeping me up nights. The bend angle of the formers need to change as you go from the bottom to the top. Mine are all the same (100 deg. or so) and won't allow the formers front edge to contact the skin at the bottom without readjustment. Readjusting causes a nasty curve in the former that I don't have the tools or talent to remove.

With all the trouble I've had with "hidden hole construction" (sorry......matched hole construction), I really envy you builders that had the opportunity to drill your own holes.

F.Y.I., page WIX-F19, general construction order #2 says to assemble the -02 skin assembly.

Thanks for playing along with Area 51%. Randy.

[Bryan Cotton]

Randy,
Pictures would be good. On all the bulkheads you push them up for a tight fit after the skin is clecoed to the fuselage. The last one you should be able to get pretty good, though I needed a couple shims on the lower tabs.

Regarding the non-uniform bends on the forward bulkhead, the important skills are patience and perseverance. Make small adjustments, check fit, rinse and repeat as necessary. You'll get it.

[garyb]

I talked to someone with a scratchbuilt Sonex with no waviness on the turtledeck. He said he took a dowel and tapped from the inside of the fuselage on the turtledeck formers that were giving him waviness. I believe he said he drilled a hole in the end of the dowel that fit around the rivet.

I haven't tried the technique--my skin isn't perfect, but I pushed the formers into position from the inside and they fit pretty well.

I also used this technique with great results no dents at all.

[Area 51%]

So........the way I'm reading this is the dowel tapping happens after the formers and rivets are installed? With my shaking hands and uncertainty of the process, I'm quite likely to have dents going toward the outside of the skin instead of a light distortion going inward.

Pictures........ah.........pictures. I wish I had the computer skills to upload pictures. I still can't get the time to quit blinking on the VCR. Any pics I've had to send to Sonex were taken and sent by a friend. Very effective as Kerry and I speak different forms of the English language. I've got a whole camera full of pics of the project. I suppose it would be in my best interest to learn how to do it.

I did manage to coax the LH #1 former into my way of thinking. While trying to get Mr. RH into position, I noticed a crack around one of the flutes. Thinking I wouldn't be too happy with a crack that size in the windshield of a new $30,000 car, I ordered , at my own expence, a replacement and received it in the mail yesterday. ( I figured I would have to sacrifice the original in the name of learning flange adjustment......I didn't) It was crack-free, however the fluting "guy" got a little overzealous with his task, and installed, along with the flutes, three nice sized dents at the top of the former. Not in some obscure un-seen location, but right at the top in the front. Not sure how I feel about three large dents in the hood of the mythical $30,000 car. No structural issue to be sure, but having to view them with every entrance and explaining to onlookers that it wasn't my fault doesn't sit well. Guess it's time to bother Kerry again.
They say, "third time's the charm".

#5 has yet to show up, but is on it's way. The person in shipping, Ryan I think his name is, is really on top of things.

Area 51% signing off.