[avee8tor13]

Is one preferred over the other?

 

[danielhv]

Depends where they are being used...

 

[Greg Arehart]

I would use the grommets in places where you don't want the wire or tube to shift laterally (through the hole) - i.e., where you want to actually hold the wire/tube. Snap bushings provide protection from chafing also, but allow the wire/tube to move laterally. Of course, you can always RTV the snap bushings to keep things from moving or to seal things up (such as on the firewall).

my 2c worth

greg

 

[Jim Percy]

I used a lot more snap bushings than grommets mostly because they take up less of the hole. You can use a smaller hole in the structure to carry more wire. They're lighter weight, and I'm guessing they'd be less prone to degrade over time due to heat, ozone, etc. I did use a few grommets, mostly the small ones where I only had a wire or two, or I didn't have enough clearance for the extra length of the snap bushing.

 

[sglynn]

dissolve

The rubber ones dissolve pretty fast in fuel. So for in the wing, they just don't seem airplane worthy to me.

 

[avee8tor13]

Gentlemen, thank you for your responses.

I noticed Vans used grommets to hold the fuel lines under the seat, my guess is to keep them from moving around and maybe to absorb vibration?

 

[kcameron]

I used silicone rubber grommets

In my recent refit of my RV-4, I replaced a bunch of old cracked black rubber grommets with red silicone grommets from McMaser-Carr: http://www.mcmaster.com/#1061t63/=19brcw

I expect these to last as long as the plane.

 

[Jamie]

I noticed Vans used grommets to hold the fuel lines under the seat, my guess is to keep them from moving around and maybe to absorb vibration?

You have to be more specific. Which model are you talking about?

Per the plans, the -7/-7A has a large rubber grommet to allow the fuel line to penetrate the fuselage sides but nowhere under the seat.