New holes through main spar web RV-6

[JordanGrant]

I want to move my fire extinguisher to be securely mounted to the front of the main spar on the pilot side (easily accessible in flight). The easiest way for me to mount it would be to drill some new holes through the main spar webs for long AN3 bolts. I would need to be very careful to avoid touching the main heavy parts of the main spar (the heavy aluminum bar at the bottom at top), but there is plenty of area in the middle that is just the thin web that presumably is not carrying any load for the wing.

Before I go drilling on the spar, though - any gotchas I'm not thinking of? Any reason I shouldn't do it that way?

Thanks for your thoughts!

[BobTurner]

Originally Posted by JordanGrant

is just the thin web that presumably is not carrying any load for the wing.
Thanks for your thoughts!

That ?thin web? carries the shear load which, by connecting the upper and lower spar caps (think ?I beam?) makes the assembly much harder to bend. My rule is to contact Vans before drilling any non-plan holes in any part of the spar assembly.

[Bicyclops]

Originally Posted by JordanGrant

I want to move my fire extinguisher to be securely mounted to the front of the main spar on the pilot side (easily accessible in flight). The easiest way for me to mount it would be to drill some new holes through the main spar webs for long AN3 bolts. I would need to be very careful to avoid touching the main heavy parts of the main spar (the heavy aluminum bar at the bottom at top), but there is plenty of area in the middle that is just the thin web that presumably is not carrying any load for the wing.

Before I go drilling on the spar, though - any gotchas I'm not thinking of? Any reason I shouldn't do it that way?

Thanks for your thoughts!

Why not use some longer bolts through the existing holes? I'd be really leery about drilling the spar.

Ed Holyoke

[rocketman1988]

"...but there is plenty of area in the middle that is just the thin web that presumably is not carrying any load for the wing..."


TLAR engineering is not advised here...call Van's; as has been posted, that is a shear web and it is there for a reason...

[Scott Hersha]

Actually, that spar web is carrying some , if not most, of the load. You may see large holes in the outboard sections of the web in some RV types, but these are in lower stressed areas. Contact Vans before modifying this critical part of the design.

[JordanGrant]

Thanks for the thoughtful comments. I agree with the collective wisdom - time to consult the pros before drilling holes in that location. I have the question in with Van's to see what they say.

Cheers!

[noelf]

Some comments from a loooong time ago about drilling holes in the spar web:

This may have come from this forum or the matronics list server many years ago, but here goes...

The RV-6 has one factory provided hole in the left wing spar web to allow the manual pitch trim cable to pass through. It was desired by builders to drill an additional hole to allow wiring to pass from the front side to the aft side of the spar. After some years of "deliberation" I believer Van allowed a mirror image of the existing hole that was provided in the left wing spar web to be implemented in the right wing spar web.

As others have stated above, it is best to call Van's support.

[lr172]

Originally Posted by noelf

Some comments from a loooong time ago about drilling holes in the spar web:

This may have come from this forum or the matronics list server many years ago, but here goes...

The RV-6 has one factory provided hole in the left wing spar web to allow the manual pitch trim cable to pass through. It was desired by builders to drill an additional hole to allow wiring to pass from the front side to the aft side of the spar. After some years of "deliberation" I believer Van allowed a mirror image of the existing hole that was provided in the left wing spar web to be implemented in the right wing spar web.

As others have stated above, it is best to call Van's support.

I recall Van's adamantly stating that additional holes cannot be drilled in that piece, especially not in the middle of it. They were reluctant to allow another 5/8" hole at the extreme end of it. I feel pretty confidant they will not endorse any hole drilled in the middle of it.

Larry

[az_gila]

Originally Posted by lr172

I recall Van's adamantly stating that additional holes cannot be drilled in that piece, especially not in the middle of it. They were reluctant to allow another 5/8" hole at the extreme end of it. I feel pretty confidant they will not endorse any hole drilled in the middle of it.

Larry

rvbuilder2002 says -

Since it hasn't been mentioned....
It is acceptable to make a second hole in the right side spar stub, mirror image of the one on the left side originally intended for the manual pitch trim cable.

[alpinelakespilot2000]

Just attach the extinguisher to the front spar covers over the fuel lines using the screw holes going into the z brackets. (Assuming the 6 has those like the 7 and 9 do... apologies in advance if this is a misassumption.) That’s where mine is. Going into the spar itself seems like overkill to me.