Skybolt CLoc Cowling Fasteners

[NBowers]

Skybolt innovated and developed Vans RV cowling fasteners in the early 1990s while we constructed our RV4. Actually, we did not invent the fastener, we simply adapted proven technology to a new market. Yes, we did make it better with several features you can see and many you can't. It was through that Vans RV project that I designed (somewhere between Nat Track 20W and 30W) and eventually perfected the US patented (5,795,122) adjustable receptacle. (Since that project was completed, we have been very active at Oshkosh and Sun N Fun meeting face to face with hundreds (thousands?) of builders). This year, Skybolt will establish hands on forums to better interact with the builder. We have teamed with cowling builders Sam and Will James to obtain a wealth of information on cowlings specific to the Vans RV (and other) kit designs. I discovered, by flying our RV4, the first bulging issue that has caught a lot of attention on these forums. Working with James Aircraft, we resolved the bulging issue, not unlike every manufacturer of any type of external panels or cowlings that fly. That includes commercial jets that tend to exceed airspeeds greater than the common RV aircraft. I built internal doublers that were a work of art, but, like Sam James warned me, they would be too pricey to sell to the average builder. So, together, we came up with "Skybeam" as a very lightweight and extremely structural material that is a simple lay-up application. Skybeam is very cost effective and resolves the structural problem for older generation cowlings. Over the years, Skybolt has worked directly with countless builders to successfully develop a fastener kit that is user friendly at a reasonable cost relative to the average RV investment. It will never compete with hinge pricing for obvious reasons.

I have noted quite a bit of discussion on the forum about proper stud lengths. Our kits use the CLoc -2 stud. We have even used -O length studs in some applications (with modifications). The problem with common stud lengths less than -2 is the unique grommet required. 99.9% of every project I have been involved in, the -2 studs work perfectly. Unfortunately, a competitor was distributing -3 studs using (might I suggest copying) our old instructions that were designed for early 1990 fiberglass (tank) cowlings like we used on our RV4. I also noted the resolve while they attempt to re-invent the wheel at a cost to the builder. I find that unfortunate. Notching a standard grommet will work for short studs; unfortunately, they will not meet our strength requirements. The specific Camloc grommet designed for those short studs do not have a flush appearance. Just because it is experimental does not relieve good common sense. Remember, we pride ourselves on airplanes that cruise at 200mph.

Another sad item I noted in pictures of one of the nicest RV7 projects I've seen, are holes drilled off center. Skybolt kits include simple drill templates that would have prevented that.

As far as the movement of the "floating" receptacles (we also make an adjustable SK215-4 that is rigid): In a properly designed cowling (such as a Beech Baron, Cessna 210, Aerostar.....all aircraft that see similar airspeeds as a Vans aircraft), if the float were an issue, those aircraft would never fly. When we talk about 3-4 inches of spacing, they use 8 and 10 inches of spacing. How? Look at the internal structure. When properly installed, a CLoc cowling (using flaoting receptacles) will perform flawlessly.

Finally, the group buy programs. I will yield to our competitor. That is (was) a great marketing tool. While Skybolt will always provide a more up to date kit with extensive hands on experience built into our kits (we simply walk through a door into our own maintenance hangar), it is our goal to actively compete in the very market we developed. Our 2007 kits are completely revised for the new generation cowling that takes into account a balance between structural requirements (hole spacing) and economic flexibility. Skybolt offers several kit versions from complete to a very economical kit that simply does the upper firewall. Every builder has their own idea of a balance between fully functional and economics. We can supply those requirements. Skybolt kits include required fastening hardware for the nose section, and the required drill templates to drill perfect holes. We also provide options for oil doors and other exterior and interior panels utilizing lightweight "Skytanium" fasteners. (The all stainless receptacle option accomplishes nothing but adding weight (and cost) and will not add any notable performance advantage over our standard receptacle).

After reviewing the group buy program, Skybolt 2007 RV Kits were specifically designed for better value while adding fasteners for those applications leaning toward 3 versus 4 inch spacing. Our group buy program is simple: Call us (its on our dime) 1-800-223-1963. Order your kit on your terms for delivery now, next month, or the month after that. Have a question? It?s on our dime and we welcome questions and give answers that are real time, hands on. Through Sun N Fun, we are also including other valuable packages on complete kits! We invite you to review our website, www.skybolt.com for the most up to date kit lists and pricing.

As an active aviator, builder, and designer: know your product, know your source, build the best and be safe.

Ned Bowers,
Skybolt

[Caveman]

Guys, I just took Mr. Bowers up on his offer. I called the toll free # & I talked to two very accomodating & helpful ladies. I won't spoil the surprise but let's just say I have a smile on my face after dealing with Skybolt. I am not affiliated with them in any manner and this may be a bit premature as I haven't received my parts yet. However, if your in the market, I encourage you to give them a call.

[Radomir]

Originally Posted by NBowers

As far as the movement of the "floating" receptacles (we also make an adjustable SK215-4 that is rigid): In a properly designed cowling (such as a Beech Baron, Cessna 210, Aerostar.....all aircraft that see similar airspeeds as a Vans aircraft), if the float were an issue, those aircraft would never fly. When we talk about 3-4 inches of spacing, they use 8 and 10 inches of spacing. How? Look at the internal structure. When properly installed, a CLoc cowling (using flaoting receptacles) will perform flawlessly.

Ned Bowers,
Skybolt

Ned, would you go in more detail about this point? What about the internal structure makes 8-10 inches work? What is this internal structure and why is it not the same on RV's? Cirrus uses 4 camlocs on the horizontal cowl split (and it's a longer cowl too!).. we're suggested to use 12 (since kit contains 24 fasteners)... why? Also, what does "properly installed" refer to?

I'm just not too excited about popping off 50+ fasteners every time I want to take the cowl off.

Thanks!

[RV_7A]

What prices are you offering on your group purchases Ned?

-Jeff

[sprucemoose]

Originally Posted by Radomir

I'm just not too excited about popping off 50+ fasteners every time I want to take the cowl off.

Would you be excited about taking out the hinge pins every time?

I've been happily flying for 3 years with 46 Skybolts holding my cowl on. They are $ compared to piano hinges, but so very much worth it. I consider them the second best expensive option on my -6.

[Radomir]

Jeff, I've done it enough times w/ hinges and you know the answer

I just haven't been able to get a good answer regarding spacing.. and discrepancy between rv kit vs certified world..

[NBowers]

The Skybolt Group Buy is simple: There is none.

We re-designed our 2007 Kits specifically for new generation cowlings provided by James or Vans. Our previous kits included our Skybeam material that we now offer as an option. We added fastener sets to most kits. I preferred the Skybeam route, but to function in the discount world, we feel compelled to compare fastener counts and leave the material as an option. Skybeam can be added to any kit at any time. In fact, it can be added to the inner structure of a cowling even after the aircraft has flown. The nice thing about current generation cowlings, they are designed to carry fastener loads at 4" spacing. 3.5" spacing is fine, however, 4" works just as fine. The Skybolt 2007 kits assume 3.5" to 4" spacing.

The Skybolt 2007 Vans RV Kits are being placed on our website as we speak. We offer 15% discount to any builder kind enough to call us (on our dime), 1-800-223-1963. When we factor price only, we may be anywhere from a few dollars less to $50 or $60 more (after their 30% discount). If we compare fastener sets, hardare, and some cases, tooling, Skybolt may just be the better value. Part of this value is the hands on experience we create each and every day in our own shop working on our own airplanes. When we send you a set of instructions, they are instructions we wrote. And when you call, remember our name, Skybolt. We stock an enormous inventory of AN-MS-NAS fasteners. Our catalog is posted on our website, www.skybolt.com.

Our group buy is an everyday buy.

Regards,

Ned Bowers,
Skybolt

[RV_7A]

Looks kinda pricey comparatively speaking. I'm happy with my MilSpec purchase and service.

-Jeff

[RV7Guy]

Skybolt is offering a deal that people can either do or not do. This is not the place to start bashing them or recommending another company. Do that in another thread.

Regarding spacing, I flew in my neighbors 8 with 4" spacing and observed considerable puckering at cruise speed. I went with 3.5" spacing and don't have any buckling.

From my experience, I wouldn't do any less than 3.5". Installation is obviously more time consuming than the hinge but they look great. Also I can have my cowl off in approximately 2 minutes.

I would definitely do Skybolts again. I would do them down the sides as well.

[NBowers]

Regarding the question as to why kit plane cowlings bulge with fasteners and certified aircraft do not: All Beech, Cessna, Piper, aircraft have fabricated inner structure riveted adjacent to or in conjunction (as a doubler at the fastener hole itself) with the fastener The Cessna cowls that use a rubber platemount around the firewall use a U channel all the way around the cowling and add to the thickness fastened. This is not practical in the case of an RV cowling. Therefore a doubler adjacent to the fastener line (cowling split) will serve to carry the concentrated load between fasteners. Remember, Vans, and most kit aircraft were designed for hinge and hinge is like a zipper with a constant load bearing along the seem (hinge pin). If we construct an extruded doubler, say along the sides, that doubler can carry the concentrated fastener load, even if the fasteners are 6, 8, or even 10 inches apart.

I built an RV8 cowling that was a previous James cowling constructed as a skin only cowl. In other words, there was no internal structure. All the new generation cowlings have lay-up structure built in. With the older RV8 cowling, I took a 3" metal strip and clamped it along the lower side. I then took a cut strip of plywood 10" wide and 60" long and scribed a line along the contour of the cowling. I then cut along this line, added 3/4" and made a parallel cut thus I had a ? inch wide curved strip of wood that followed the contour of the lower cowl along the side (where the hinge would mount). I then screwed the wood strip to the metal strip. Finally, I shaved and sanded the strip into a curved edge. The finished piece became the tool from which I fabricated a mold to fabricate the finished composite doubler, just like the side double on any C172, or C182 would have in extruded aluminum. The fabricated piece is symmetrical to either side, so I made two parts. With this strip bonded and riveted into place, I had a cowling that only required, say 6? spacing between fasteners. I used 4? anyway, but that was overkill. That cowling has been to Oshkosh 3 times and SunNFun 6 times. As part of our display, I bet I took that cowling off and on 4,000 times and it works perfectly (it never flew because it was a stand display). Point is, the fasteners worked perfectly. Now fabricating doublers requires a small allotment of time, but it resolves any and all bulging issues and looks very professional. (As soon as I figure out how to paste pictures, I?ll do so. The pictures show the doubler I made and the Skybeam.

The RV8 that was mentioned in the forum with 4? spacing that bulged, was probably a pre-new generation re-enforced cowling. Even so, doublers can be added after the aircraft is flown.

The other solution that Skybolt has had in all our previous kits is Skybeam (it is an option in our current kits, as you may or may not need it as we followed the trend towards 3.5 inch spacing). It is the no brainer way to add structure along the firewall, adjacent (forward) to the fastener line, and along the sides, adjacent to the seam.

To comment on floating receptacles, they are designed to float enough to aid in fastener engagement and they work quite well. When the CLoc studs are locked, the assembly is functionally clamped and any cowling movement should be a non-issue once the cowling is completely installed. Having worked on thousands of cowlings (Skybolt manufactured composite Cessna cowlings for 10 years and sold that division), hundreds of STC fastener conversions, I can see no difference in the RV cowling going 180 mph and, say a 210 going 180 mph. All of those cowlings use floating receptacles.

The Camloc and CLoc design have been around for decades with millions of flight hours. What I designed for the RV series follows the best designs I know in certified designs. The secret is the internal load carrying structure and I have described a couple of ways to achieve that. The Sam James cowlings, I know, are specifically designed for load carrying capability via the internal doubler structure that is super lightweight but very strong. James places the material as close to the edge as possible without adding to the overlap thickness.

Keep the questions coming.

Ned Bowers,
Skybolt