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Skybolt installation

sahrens

Well Known Member
For those of you that have installed Skybolt fasteners along the firewall I have a question. The instructions tell you to drill the through the cowling in alignment with the installed skybolt flanges to 15/32". I am shortened the instructions but if you have done it you know what I am talking about.

To my question. You can cleco the cowling in place but as you drilll more and more openings for the Skybolts fasteners the clecos need to be removed. So....did you stop and install retainers and Skybolt fasteners periodically, then resume making drilling openings.

I am concerned about keeping the cowling from moving as I work from the top down both sides. What am I missing from the instructions or the process?

Thanks for you assistance.
 
skybolt

I ran into this problem myself when I did mine not so long ago. the mistake I made was that I did the skybolts across the top first before I did the piano hinge along the side. I had the gaps perfect, better then perfect and if I would of done the piano hinge on the sides first then nothing would of moved.
so doing it again I would of done the sides first and then the top. That way nothing would of moved as I did the skybolts on top.
 
Did you clamp the upper and lower in place with a strap like a cargo strap? Or did you just rely on clecos to hold the upper and lower in place?

I had been waiting to make that cut along the lower cowling until I had installed the firewall Skylocks.

Thanks for you advice.
 
after I mounted the flanges, I drilled through the cowl and into the skybolt flange and clecoed . I will have a couple holes in the flanges but I did not want it moving....at all.
 
skybolt

installation can be simple, I think. Once you have the receptacle support (either sheet metal or the available sky bolt nesting supports) installed you can find an area that is not "busy" and install a couple of clecos. They never change positions, so you can take the cowl on and off several (hundred) times and it returns to the same position.

My only caution is to make sure that your receptacle spacing allows clearance between the upper engine mount and the nearest skybolt receptacle. I would make sure that the skybolt spacing puts those two receptacles far enough away from the upper engine mount to allow the full depth of the receptacle to be used. There are ways around this issue, but it is best to avoid it to begin with.

Seriously, good luck, it was fun for me...
 
I have some posts you can find on this very subject. I don't know how you can do the sides first but like a lot of things, it depends.

Meanwhile, Yes you can certainly drill for a cleco through the "adapter" then move to the next one. In my opinion, it is hard to cinch down the cowl tight without deforming it and causing other issues. So - i drilled, installed a cleco top center and alternated outward. I found it hard to hit the holes exactly, but had a workaround to fix them before drilling. Lots more special tools, but very happy with a precise fit. I suggest having a cleco in each position for the full fitting. Maybe your cowl is more rigid, but mine was not, so they all were used.

Here is how I did it : http://www.vansairforce.com/community/showthread.php?t=114861
 
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Skybolts as you go

The answer to your question is yes.

I installed the Skybolts as I went to prevent movement of the cowl. I started by doing every third or fourth hole. I also had a steel weldment attached to the front two cylinders so the cowl inlets were positioned exactly the same each time the cowl went on and off.

I did not have any perceptible movement during the install of the Skybolts but doing it this way is a fairly slow process.
 
I am jumping in here to get some information from those that have been there and done that.
My problem is that the fairly thin cowling is being depressed in the area of the skybolt. I think this will really look bad after shiny paint is applied. I have experimented with raising the under cowling portion of the skybolt, does not seem to work very well. It appears that maybe a washer between the two parts might be in order, or perhaps actually putting some fiberglass on the inside part of the cowling to thicken and strengthen that portion. None of my ideas really seem like good ones, what have others used to solve this problem?
 
The answer to your question is yes.

I installed the Skybolts as I went to prevent movement of the cowl. I started by doing every third or fourth hole. I also had a steel weldment attached to the front two cylinders so the cowl inlets were positioned exactly the same each time the cowl went on and off.

I did not have any perceptible movement during the install of the Skybolts but doing it this way is a fairly slow process.

I would rather be slow and have the results that I want. I will use your technique.

Thanks
 
My only caution is to make sure that your receptacle spacing allows clearance between the upper engine mount and the nearest skybolt receptacle. I would make sure that the skybolt spacing puts those two receptacles far enough away from the upper engine mount to allow the full depth of the receptacle to be used. There are ways around this issue, but it is best to avoid it to begin with.

Seriously, good luck, it was fun for me...

I installed the tabs for the skybolt fasteners (homemade) before I had the engine mount on. And guess what - I don't have enough clearance with it on. So I need 2 low profile recepticals to clear the top engine mounting pads, one on each side. If you know ways around this issue I would very much appreciate any wisdom on the subject. I am currently looking for a low profile camlock receptical.
 
Did you get the cleco adapters? They made that task very straight forward. I got all the flanges installed, used clear tape to temporarily attach the cleco adapters into the large hole on the flanges, and then installed the cowling. I used a flashlight to shine through the underside of the cowling through the oil door and that allowed me to drill a 1/8 hole through the top and bottom cowling and secure a cleco. This process was problem free for me.
Here is a link to my build log showing the process.
http://www.n781td.com/logindex/FWF/2014.12.02.htm

http://www.n781td.com/logindex/FWF/2014.12.03.htm
 
First, I marked on the forward skin, where the fasteners should go, so there was no guessing on the spacing.

Then I put a trouble light in the engine compartment, shining up. This allowed me to see the tabs.

I drilled the top center one first and installed the fastener.

After replacing the top cowl, I snugged it down with ratchet straps and drilled the left and right holes. I used a cleco to hold the first hole while I drilled the second one.

The cowl was then removed, fasteners added, and reinstalled the cowl. I repeated those steps until I was finished.

When it came time for the bottom cowl, I started at the bottom edge and worked towards the center.

Then I moved to the bottom and worked up the side. This allowed me to finish sand the bottom cowl to match the top one.

Next up was the side fasteners. I started at the firewall and moved forward.

Good luck!
 
When to dimple/rivet.

I know this is an old thread but relavent to where I?m at in the process. I?m riveting up the remaining side and bottom skins before flipping the canoe. Obviously the side and bottom skins have to be dimple counter sunk at this point around the firewall. Later when installing the sky bolt fasteners around the firewall flange won?t the dimples interfere with the interlocking Skybolt flanges?
 
If I?m understanding you?re question correctly, you should be able to countersink the flanges to account for the dimples. The skybolt flanges are either .040 or .063 so you have enough thickness to countersink.
 
I know this is an old thread but relavent to where I?m at in the process. I?m riveting up the remaining side and bottom skins before flipping the canoe. Obviously the side and bottom skins have to be dimple counter sunk at this point around the firewall. Later when installing the sky bolt fasteners around the firewall flange won?t the dimples interfere with the interlocking Skybolt flanges?

Having dimples done before the skyloc's definitely adds some challenge. You will likely need a spacer too and the drill and dimple process for a long spacer under around a curve requires progressive drilling and dimpling. You might make a couple of thicknesses of spacers before you dimple. That might make the task easier. To your question, I found no particular issues with the existing dimples specific to the skylocs. And I was picky.
 
I dimpled the side skins and firewall flanges when I was preparing that area for riveting. The dimples did not make it a lot more difficult when I was adding the Skybolt flanges. But it did add to the challenge. Once I located and drilled the Skybolt flanges to match the side and top skins, I countersunk the Skybolt flanges so they would nest correctly.

I felt that was a better method than attempting to dimple the skin and the firewall flange together after riveting the side skins. Here is my build log

http://www.mykitlog.com/users/category.php?user=sdahrens&project=248&category=11167

While on the topic I used Don Jones technique for laying out the Skybolt flanges.

http://www.vansairforce.com/community/showthread.php?t=74619&highlight=skybolt
 
Bill, do you have a build site that I might be able to reference?

No, sorry Max. PM/Email if you have questions and I will gladly send photos that are available.

I dimpled the side skins and firewall flanges when I was preparing that area for riveting. The dimples did not make it a lot more difficult when I was adding the Skybolt flanges. But it did add to the challenge. Once I located and drilled the Skybolt flanges to match the side and top skins, I countersunk the Skybolt flanges so they would nest correctly.

I felt that was a better method than attempting to dimple the skin and the firewall flange together after riveting the side skins. Here is my build log

http://www.mykitlog.com/users/category.php?user=sdahrens&project=248&category=11167

While on the topic I used Don Jones technique for laying out the Skybolt flanges.

http://www.vansairforce.com/community/showthread.php?t=74619&highlight=skybolt

I did find that attempting to rivet all the layers together, that a final squeeze with the dimple dies to compress and finally align each hole just before setting the rivet yielded a nicely compressed stack and a straight/flat fuse skin. Dimple squeeze, rivet set, repeat.

You might want to consider adding your fire barrier in the riveting process and the nooks and crannies are hard to access afterward. I did not :(.
As always, YMMV

PS I used a single piece straight top rail for the cowl split not the skylocs. All those jagged pieces sticking up just make the upper cowl installation more difficult (per DanH).
 
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Very helpful all. I just wanted to see how hard the skylocks would be before I got too happy with the dimple dies. Also do y?all recommend 100% fasteners or just firewall with the hinges along the sides of the cowling. Thanks!
 
Very helpful all. I just wanted to see how hard the skylocks would be before I got too happy with the dimple dies. Also do y?all recommend 100% fasteners or just firewall with the hinges along the sides of the cowling. Thanks!

It is very much a personal preference.

On my RV-6 I have vertical hinges along the firewall and the horizontal hinges between the cowl halves. I have #6 screws along the bottom and top of the firewall. That's been a great setup for me except for the time it takes to remove and reinstall all of the screws.

On the RV-10, I'm going with hinges in the same places, but Milspec fasteners along the top and bottom of the firewall to eliminate the time I currently spend on the screws.
 
I used the hinge pin method along the sides of the cowling and Skybolt fasteners around the firewall, including the bottom. I like the clean line of the hinge pin, but that is strictly a personal choice.

I second Bill's recommendation about the fire seal around the firewall while riveting the side skins.
 
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