Lexan Inspection Port Covers?

[tinman]

Is there a structural reason to not use a lexan cover over the aft fuselage elevator inspection ports? Seems like this is an important area and not inspected due to the difficulty of getting the covers off.

[RickWoodall]

I asked the same a while back after seeing all the clear covers on the acros. Didnt really get any good answers. Needs to be strong, then etc but that should not be a problem with the polycarbonates etc available. It would look great, be very easy to inspect quickly and i am in if someone can suggest a suitable material.

[N520TX]

I've been flying with lexan inspection covers since day one (July 4 2004) without any problems what so ever. I got the idea to do this from the DA20 Katana aircraft that I first learned to fly.

[pazmanyflyer]

Originally Posted by N520TX

I've been flying with lexan inspection covers since day one (July 4 2004) without any problems what so ever. I got the idea to do this from the DA20 Katana aircraft that I first learned to fly.

Can you post some pictures of this?

[rvbuilder2002]

The inspection covers on RV's should be considered a structural component (as well as the baggage bulkhead panel and tunnel covers).

I'm not saying that a clear cover can not be made that is equal to the aluminum ones, but "mine have been ok since day one" is not a good reason that everyone should do it.

If someone makes a mod that reduces their wing strength to 2.5 g"s (I'm not saying that this one does that), then in all of their flying they never pull more than two G's, does that make it appropriate to say "the mod has worked fine on my airplane"....I don't think so.

My suggestion...Think very carefully about what the true value of a mod like this will be...and what the consequences might be.

[John Clark]

My concern is that just looking at a component isn't an inspection. On my last condition inspection I found a questionable rod end only because I did a "tactile inspection," tough to do through lexan.

John Clark
RV8 N18U "Sunshine"
KSBA

[boom3]

I don't have a picture of them, but a guy I know has approx 2" round plexi windows in the elevator inspection covers. It looks great and is easy to look through. I plan on doing the same thing.

[RickWoodall]

I believe some of the polycarbonates are way stronger then thin aluminum. I do agree that viewing is not as good as touching, but the point is that a quick inspection as part of the walk around would provide much more info then waiting for the annual and removing the panels. At annual, certainly remove and inspect fully(metal or lexan). Finding a thin strong and transparent plastic that would not scratch easily is the issue i believe.

[the_other_dougreeves]

FWIW, our CT uses 3" diameter plexi inspection ports at pushrod joints on the underside of the wings. Works great for making sure that the nyloc nuts are still snug and witness marks still line up. It's only used during preflight to make sure that nothing bad has happened; it's still removed for the annual and 100 hr inspection (we are required to perform a 100 hr even though we're not operating for hire....).

TODR

[John Clark]

Originally Posted by RickWoodall

I believe some of the polycarbonates are way stronger then thin aluminum. I do agree that viewing is not as good as touching, but the point is that a quick inspection as part of the walk around would provide much more info then waiting for the annual and removing the panels. At annual, certainly remove and inspect fully(metal or lexan). Finding a thin strong and transparent plastic that would not scratch easily is the issue i believe.

The tensile strength of aluminum is around 70,000 PSI, the tensile strength of polycarbonate (Lexan) is 9,500 PSI. Engineer carefully. I really like the idea of a "window" in an existing aluminum cover. With a little thought, that could be just as strong as the original plate and easier to make aerodynamically correct.

John Clark
RV8 N18U "Sunshine"
KSBA