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Cowl retaining pin

chevytoo

Member
I came back from a flight and there was a large puddle of oil under the engine. I opened the oil door on the upper cowl and saw the right hand pin that holds the cowl in place sitting on the battery. It turns out the pin had shorted between the battery and the oil pressure hose. The hose has a large leak. I obtained new hose and will assemble it and install it soon. Vans drawings do not show a retainer for the pins at the firewall. I know how I will make retainers for both top cowl pins and that will be done after I clean up the oil mess. I lost only 1/2 quart but that does make a big mess. I see the advantage of modifying the cowl attach to 1/4 turn fasteners. I am confident the vertical pins on the side of the firewall will not be a problem.
Ray
 
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You didn’t say what model of RV you have, but cowl pins work very well on all RV models that i have seen, even on the top cowl. You just need a cowl pin retainer bracket mounted on the firewall - very easy to make/install. If you have a side by side model, it may be easier to make a small access panel in the aft surface of the top cowl in the center, to access the pins and provide the locking mechanism, but that makes it even easier to remove/install your cowl. The hinge holds the cowling very securely, doesn’t pillow if done correctly, and is a fraction of the cost and weight of camlock fasteners.
I’ve used both methods, and I will be using hinges again on my current RV build.
 
I would question the installation of the "pin".

First, If a pin backed out, it would conflict with the left "pin" and would need to bend forward or down to continue to back out of the hinge.

Second, the "pin" is under tension due to the curve of the cowl and is difficult to install and remove by hand. I would say that the "pin" was not properly installed.

If your "pin" slid in and out with ease, then it was the wrong diameter. There is reason most all car manufacturers have a non metallic cover on the + terminal of the battery.

There is a reason Vans drawings do not show a retainer for the "pins" at the firewall.
 
Several months ago I inquired as to a Vans design of top pin retention…. someone shared this firewall top pin retainer. I believe this is a part in 14 kits.
 

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I've seen lots of migrated pins, retainers are a good idea especially over the battery.
That situation could have been much worse. A boot on leads also helps prevent this from happening.
 
Thanks for the feedback. I do have boots on the battery terminals. The pin slid under the boot when it fell out. The pin is the diameter per Vans drawings and was fully installed. I like the retainer in the photo and will make one similar. Ray
 
I don't have a good picture, but I just added a couple screwes to the firewall with a spacer and washer to for a T. The handle on the pin just goes behind the T under some tension. Easy peasy.
 
Easy retainer fix. Just a small section of aluminum angle riveted to the firewall. Notched out a little slot to hold the ends of the pins.

i-WrKtvfX-M.jpg
 
Great ideas here! My pins walk but then they run into each other and stop. My battery box is in the plans location (far left side of firewall) so not sure if there's a threat of a pin short.
 
Cowl retaining pin alternative solution

Here is an alternative solution, we added this about 100hrs in on our RV7 as the cowl pins would also migrate during flight.
 

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My pins can't walk

My solution on a flying plane I bought. Reason for the pop rivets. Same as the one I built.
Easy fool proof and quick.
Art
 

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no separate retainer piece

- pins are hooked at the ends to interlock.
 
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My take on a pin retainer (pin was trimmed after pic was taken). 800+ hours and no issues. Very low profile.

IMG_9423.JPG
 
Nite Ize Gear Ties

My cowl pins have finger loops on the end.

Recently I made a tool to pull and push them in place. Simplifies installing them. 10-seconds max each pin. Used to take longer, best part is my arm doesn't get stuck in the opening for the oil fill anymore when installing them.

The next issue was how to secure? Original answer took about an hour to hook both finger loops. It was a fishing lure snap wire assembly.

Took forever and a day in the small confined space to hook both finger loops. Couldn't see them; had to do everything by feel. Accidently only hook one, now add time to try and get the thing un-snapped, before trying to get both again.

A month ago I found a product called Nite Ize Gear Ties. The 6" version takes 30-seconds to secure these loops.

Bend into a hook shape, insert through both loops and twist a couple of wraps and you're done. Here is a photo of some 6" long black ones, pack of six, purchased yesterday from HDepot:
PICT1351.JPG

Rubber coated twist ties. The rubber coating protects from arcing out any electrical issues. Can't believe how well these work.

You can order direct from Nite Ize. I bought the bright yellow ones at first, now ordering the bright orange versions. Easy to verify secure on pre-flight inspections. The black ones above won't be as easy to see.

Might even work instead of zip ties to secure loose wires/cables FWF. These bend easy but feel durable. Designed to be used over and over.

Best regards,
Mike Bauer
 
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One more entry

Thanks to original builder. Works great.
 

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I can't take credit for these as I didn't make them, nor did the original builder. The guy who did the maintenance for the guy I bought it from came up with these. Really slick idea.

IMG_3889-L.jpg
 
Cowl pins

I’ve been moving those internally installed pins to the outside like the RV10 cowl pins are done. So much nicer and easier to remove and install. I’ve done this on 7s and 8s.
 

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upper cowl pin - self retaining

or something like this... you get the idea. compact and no extra pieces. 8 yrs operation and no issues.

cowl_pin.png


or more like this. install and pull them together to lock. they naturally want to migrate together during operation so they stay locked.

heat the wire red before you bend it.

pins.png
 
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I can't take credit for these as I didn't make them, nor did the original builder. The guy who did the maintenance for the guy I bought it from came up with these. Really slick idea.

IMG_3889-L.jpg

That's how mine are. It works great and is easy to release by feel.
 
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