What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Seat Panel Screws have a structural importance?

Upon reinstalling the seat panels after conditional, a fair amount of screws are not tightening(stripped) I am going to repair because it appears they are part of the wing to fuselage structure but I am wondering if anyone can either confirm or deny?
 
I think you are correct in your assessment....replace all damaged screws so they can be secured properly.

Application of BoeLube or wax to the screws will make them thread into the plate nuts easier.
 
Upon reinstalling the seat panels after conditional, a fair amount of screws are not tightening(stripped) I am going to repair because it appears they are part of the wing to fuselage structure but I am wondering if anyone can either confirm or deny?

Do you mean that the threads are stripped, or that the phillips head is stripped? As I've removed my floor for some avionics work and will be reinstalling, I've noticed that many of the heads are stripped and lately have been buying those MS-35206 screws by the handful. I also try to be diligent about using a new bit for removing or installing and making sure that the clutch on the screwdriver is set low.
 
JIS screwdriver or bit

Phillips head screws/screwdrivers are designed to "cam out", so in a non-production environment the screw head will strip with high torque, which is often required with platenuts. One solution that I have found works well is to use a JIS screwdriver or bit with Phillips screws. JIS screws are used on Japanese motorcycles - they are not designed to cam out, and a JIS bit or screwdriver works very well on a Phillips head screw, is not designed to cam out and so will not strip the head.
 
Anti cam out

I’m sort of surprised no one has mentioned the anti cam out screwdriver bits - been using them for years. A web search will find them.;)
 
JIS Rocks

The JIS bit mentioned earlier changed my life. Cad plate and normal phillips do not get along well.
 
I was under the impression that both the Wera PosiDriv bits and the JIS bits were designed for proprietary PosiDriv screws and JIS-specific screws. Not true?

I've been using high-quality Milwaukee or Bosch #2 bits and pitch them out frequently. Seems to work pretty well so far.
 
structure? yes.

To answer the OP's question, the answer is yes. In a monocoque structure, just about every panel contributes to torsional stiffness in one way or another. Every bulkhead cover, seat pan, baggage floor, that sort of thing, closes out bays that create torsional stiffness.

Torsional stiffness is especially challenging in the cockpit area where the main fuselage 'tube' is cut open to create the cockpit. If you want to visualize this, take an empty paper towel tube, and cut a rectangular hole in it roughly in proportion to what your RV-6,7,8,9 cockpit opening is. Now twist the tube and watch.

Lots of modifications can reduce or even cripple torsional strength. A common one is the access panel that people put in the bulkhead of RV-8s between the instrument panel area and the baggage compartment. If that access panel closes with lots of screws along the perimeter of the cut-out, great. If it just has a latch or two along one edge, not good. Another approach besides lots of screws around the perimeter would be to put a heavy doubler around it -- the bulkhead contributes to torsional stiffness by maintaining the cross section shape. A doubler will help do that - it basically prevents the compromised bulkhead from buckling.
 
Thanks Steve for the analogy. After looking at how everything is put together and thinking it through, I could only conclude they were critical to the structure. However, I was thinking it was more critical to the wing to fuselage assembly. Your description certainly makes sense as well. However does not the latched canopy also contribute to creating torsional stiffness? Or not so much?

The problem I was having was a few of the screw threads had stripped out. Easy fix. I am happy to report the assembly was put together better than how I found it!
Piece of Mind.
 
However does not the latched canopy also contribute to creating torsional stiffness? Or not so much?

The contribution of these latched canopies (talking about an RV), to overall fuselage torsional stiffness, is exceptionally small. I would be surprised if Vans engineers even considered it seriously in their margin calculations.
 
Seat Panel Screws

I bought the Vessel brand of JIS screwdrivers on Amazon, cheaper and appears to be the same one McMasters sells. My whole wall of Philips screwdrivers are now just collecting dust. Has definitely changed my view of Philips screws!
 
I bought the Vessel brand of JIS screwdrivers on Amazon, cheaper and appears to be the same one McMasters sells. My whole wall of Philips screwdrivers are now just collecting dust. Has definitely changed my view of Philips screws!

so...a question:

It appears that JIS screwdrivers are designed to work with JIS screws. It also appears that using a US Phillips screwdriver in a JIS screw will have a higher potential for damaging the screw. What about using a JIS screwdriver or bit with US Phillips screws? Does that allow more torque with less potential for damage to the Phillips screw?
 
so...a question:

It appears that JIS screwdrivers are designed to work with JIS screws. It also appears that using a US Phillips screwdriver in a JIS screw will have a higher potential for damaging the screw. What about using a JIS screwdriver or bit with US Phillips screws? Does that allow more torque with less potential for damage to the Phillips screw?

This is exactly what everyone is doing - using the JIS screwdriver with their standard Phillips head screws....and it works great!

I think I have four JIS drivers scattered about the shop[ now, and the Phillips drivers are put away.
 
Back
Top