Skybolt Experience ?? Floaters vs Fixed
 

I am fitting my cowling and have an old Skybolt set (2004ish never opened) with all floating receptacles. The Skybolt instructions imply that they now only recommend 6 floaters on the firewall. I don't know what is used along the cowl sides.

Skybolt (mil spec too) users with some hours on, what is your experience with all floaters? If not favorable, where should fixed be used vs the floaters?

Your help is appreciated.

Thanks

I am installing skybolts on my cowling as well, and their instructions for the floaters seems vague. I guess I don't understand what they will do for me.

The floaters were recommended to be installed around the firewall.


Glenn Wilkinson

This is what the instructions say, and the second photo is what they recommend. Maybe when done it will make sense, but to just read it something gets lost in the reasons:
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OK, as stated in the OP I have ALL floating receptacles - ALL 48 of them, NO fixed at all.

Historically, when the Skybolt kits were first (to my knowledge) used in early 2000's all floaters were used. Apparently, there were a lot of people that had trouble with all of them as there was cowl movement when fastened. Skybolt kindly swapped out for existing customers, and changed the kits to have much fewer floaters ( down to 6??) and the remainder became fixed (real facts needed here).

I am trying to get direct connection with owners with skybolt fasteners, of all combinations, to come to a conclusion about what to do as I believe it is universal that all floaters will not result in a sufficiently rigid cowl.

I would think it would allow that portion of the cowl to mount differently each time if all were used.
I wonder if they want them used on the ends of the bottom cowl as well? I am using them all around on my cowl.

They should
 

Ned is good people. I'm sure he will swap out as needed. They've been great to me and easy to work with.

I used all floaters on the firewall. When I replace the bottom cowling, I simply fasten only two or so at the split line so I can get the front baffling in position. Then I attach the upper cowling with two fasteners attached. Next, I insert my side pins into the hinges. I stand in front and wriggle/seat the cowling in its "natural" spot and then proceed to secure all the fasteners.

It simply doesn't move after that. Remember that the fasteners are adjustable in depth and that allows you to set a comfortable yet firm grip. With 25 or so fasteners and the hinge pins it simply is not going to move.

At least that has been my experience so far.

Don

I am using Skybolts for connecting the two halves, as well as to the firewall

Floaters
 

I am using the Skybolt system on my RV-8 for 135 hrs now and have No Problems with them . I have Floaters on the Firewall and Non Floaters on the seam between the upper cowl and lower cowl . I also have one #8 screw on each air in let outer and 3ea. #8 screws to the spinner side . It works well for me . :) That being said ------ if I were to do it again I think I would not use the Floaters on the Lower cowl verticle lt. & rt. Sides , I would use Vans Hinges and pins here only ! I think it would be easier to put the lower cowl in place drop the the pins streight down and it is all firmly in place ! Then use the Skybolt fasteners to finish the attachment of the cowl , butta bing / butta bang !:D

An all-floating setup may be fine, but it's not necessary. In the photo, three floaters in each upper corner allow the fasteners to self-enter the receptacles when the cowl is set into place. All the others are solid mounts.

BTW, if done over I would not scallop the mounting strip for the lowest two of those three. The last scallop can catch the corner of the cowl and chip paint. Same for the straight sections along the sides of the lower cowl...no scallops.

Why floaters are bad
 

When you install the floaters on a new install, everything seems fine. And it is for the first 500 hours or so. What you find is that since the floaters float, they wear out the holes in the fiberglass as your engine moves around. The result is that over time the holes wear larger and larger to the point that the paint wears, holes enlarge, screws fall out when removing the cowl, and eventually its a mess. Ask me how I know.
All of my holes in the cowl are completely wore out. All the male screws fall out when you unlatch to remover the cowl, and the cowl moves A LOT now. I can lift on the fwd cowl when attached and move my entire cowl around. The fix for this is AWFUL. Means a new cowl.

One fix they had to keep the screws in was a larger c-clip. I went to those about 1k hours ago. Worked for a few hundred hours but eventually it wore beyond what the larger clips could retain. ARGH!

Note: Im certain that the type of aggressive flying I do, exacerbates the problem. If your pulling positive and negative G's a lot, your stressing these cams on the fiberglass forcing a lot of joint movement. I would NOT do floaters again anywhere on my cowl.

Thanks for that information. Of course if I flew my 12 as you do your airplane, the tail would fall off long before my cowling was worn out :D
I am thinking on using my floaters as they recommend as of now.

Even the fixed receptacles are not very tight and allow some movement. My rocket has hinges for the cowling sides and the fixed Skybolt receptacles around the firewall. There is some movement of the cowling that can occur as Kahuna points out and I have considered adding 2 regular screws and nutplates to stop the movement. Which kind of defeats the purpose of camlocks. If I had to do it over again I would just go with #10 flush screws and tinnerman washers. Cheap, much easier to install, easier to replace. Most of the time I use an electric screwdriver to remove screws so the time savings and convenience of camlocs isn't all that that much better.

Funny that there doesn't seem to be a universally preferred setup after all these years. I've grown weary of my installation with ten #6 screws across the top of the firewall plus eight #6's and two #8's across the bottom of the firewall. There are 40 individual pieces of hardware along the firewall (20 screws plus 20 tinnermans), the side hinges, and the screws at the inlets every time I pull the cowl.

I will say that my setup has held up well.

I wonder if anyone makes industrial strength Velcro. ;-)

SkyBolt
 

I have floaters all the way on the top. Doing it again, I would probably use screws.
I have had 2 issues with the floaters.
1. I have had several of the self adjusting mechanisms fail even after making sure the ball is aligned in its slot.
2. I have had several of the floaters fall out of their retainers.

Thanks Dan, I called Skybolt and they will swap my package for a new one with only 6 floaters, just like you recommend. I will make the cowl split straight with fiberglass, like you and a previous poster recommend.

Thanks Kahuna, I remembered someone from a few years ago that said this, it must have been you. I asked the SB people about shear vibration testing and they said none was done. Thanks for your experience.

Thanks Bob, I plan to use the nut-plate method on the nose section to get better coverage. Good to hear it may be actually better.
Thanks for adding to the collective knowledge.

Thanks ALL for helping to get this documented. It is great to learn from the experience of others. I just hope my plane turns out half as good as yours.

Floaters and Worn Holes
 

Skybolt just introduced our new adjusting floating receptacle that uses a clip retained cage versus our old fold over ear cage. We now perform a variety of tests on everything we make that goes far beyond Mil 5591 or NASM5591 that includes push out tests (200% over the minimum) and vibratory fatigue tests, to name a few.

We also have introduced our new DiamondHead Phillips fastener with a 42Rc hardness. What this means is that these studs will not gall, something that has been on my radar for years to resolve. In the process, we pushed the performance ratings for 300 stainless beyond the steel ratings.

The timing of this forum is great in that we are working on a grommet revision that surfaced in another application. We discovered some design limits that have been part of industry standard grommets for decades. Some work I have done with Cessna also focuses on worn holes and how we can eliminate or substantially subdue wear. Part of it has to do with the tiny radius on the ledge associated with the retainer and the retainer itself. And part of it has to do with the grommet undercut. We just solved all of this and I can immediately revise our Vans kits to take advantage of this. We are running these parts as we speak and will revise our kits in the next week. If you have a previous kit and want to swap grommets, email me at nedcbowers@yahoo.com and I will take care of it. In summary, I think we are are a good track to address cowling float and worn holes.

More innovations are on the way........Skybolt installation instructions are posted on our website. Call or email me with suggestions or questions. On another post, I want to talk about installation of flanges prior to engine installation.

Ned Bowers, Skybolt

Maybe too late for the original post, but for posterity, what I did was use hinges everywhere except on the firewall part of the top cowl. This makes taking off the top cowl very easy (a few screws for the hinge pin keepers and behind the spinner, and the floating skybolts on the firewall). Has worked well for almost 700 hours and 5.5 years now with little sign of excessive hole wear or slop in the cowl.

That's my experience anyway.

Greg

On a Viking cowl for an RV12, that little dogleg at the firewall gets to be pretty busy with the Skybolts!
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Email sent, Ned.